diff mbox

[2/3] cpufreq: exynos: Adding cpufreq driver for exynos5440

Message ID 1360179562-19950-2-git-send-email-amit.daniel@samsung.com
State New, archived
Headers show

Commit Message

Amit Kachhap Feb. 6, 2013, 7:39 p.m. UTC
This patch adds dvfs support for exynos5440 SOC. The nature of exynos5440
clock controller is different from previous exynos controllers so not using
the common exynos cpufreq framework. Also, the device tree parsing is added
to get different parameters like frequency, voltage etc.

Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
---
 .../bindings/cpufreq/cpufreq-exynos5440.txt        |   24 ++
 drivers/cpufreq/Kconfig.arm                        |    8 +
 drivers/cpufreq/Makefile                           |    1 +
 drivers/cpufreq/exynos5440-cpufreq.c               |  448 ++++++++++++++++++++
 4 files changed, 481 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
 create mode 100644 drivers/cpufreq/exynos5440-cpufreq.c

Comments

Inderpal Singh Feb. 7, 2013, 5:09 a.m. UTC | #1
On 7 February 2013 01:09, Amit Daniel Kachhap <amit.daniel@samsung.com> wrote:
> This patch adds dvfs support for exynos5440 SOC. The nature of exynos5440
> clock controller is different from previous exynos controllers so not using
> the common exynos cpufreq framework. Also, the device tree parsing is added
> to get different parameters like frequency, voltage etc.
>
> Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
> ---
>  .../bindings/cpufreq/cpufreq-exynos5440.txt        |   24 ++
>  drivers/cpufreq/Kconfig.arm                        |    8 +
>  drivers/cpufreq/Makefile                           |    1 +
>  drivers/cpufreq/exynos5440-cpufreq.c               |  448 ++++++++++++++++++++
>  4 files changed, 481 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
>  create mode 100644 drivers/cpufreq/exynos5440-cpufreq.c
>
> diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
> new file mode 100644
> index 0000000..96cb0ed
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
> @@ -0,0 +1,24 @@
> +
> +Exynos5440 cpufreq driver
> +-------------------
> +
> +Exynos5440 SoC cpufreq driver for CPU frequency scaling.
> +
> +Required properties:
> +- interrupts: Interrupt to know the completion of cpu frequency change.
> +- cpufreq_tbl: Table of frequencies and voltage CPU could be transitioned into,
> +       in the decreasing order. Frequency should be in KHZ units and voltage
> +       should be in microvolts.
> +
> +All the required listed above must be defined under node cpufreq.
> +
> +Example:
> +--------
> +       cpufreq@160000 {
> +               compatible = "samsung,exynos5440-cpufreq";
> +               reg = <0x160000 0x1000>;
> +               interrupts = <0 57 0>;
> +               cpufreq_tbl = < 1200000 1025000
> +                               1000000 975000
> +                               800000  925000 >;
> +       };
> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> index a0b3661..554756f 100644
> --- a/drivers/cpufreq/Kconfig.arm
> +++ b/drivers/cpufreq/Kconfig.arm
> @@ -77,6 +77,14 @@ config ARM_EXYNOS5250_CPUFREQ
>           This adds the CPUFreq driver for Samsung EXYNOS5250
>           SoC.
>
> +config ARM_EXYNOS5440_CPUFREQ
> +       def_bool SOC_EXYNOS5440
> +       help
> +         This adds the CPUFreq driver for Samsung EXYNOS5440
> +         SoC. The nature of exynos5440 clock controller is
> +         different than previous exynos controllers so not using
> +         the common exynos framework.
> +
>  config ARM_SPEAR_CPUFREQ
>         bool "SPEAr CPUFreq support"
>         depends on PLAT_SPEAR
> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
> index fadc4d4..5159ba4 100644
> --- a/drivers/cpufreq/Makefile
> +++ b/drivers/cpufreq/Makefile
> @@ -50,6 +50,7 @@ obj-$(CONFIG_ARM_EXYNOS_CPUFREQ)      += exynos-cpufreq.o
>  obj-$(CONFIG_ARM_EXYNOS4210_CPUFREQ)   += exynos4210-cpufreq.o
>  obj-$(CONFIG_ARM_EXYNOS4X12_CPUFREQ)   += exynos4x12-cpufreq.o
>  obj-$(CONFIG_ARM_EXYNOS5250_CPUFREQ)   += exynos5250-cpufreq.o
> +obj-$(CONFIG_ARM_EXYNOS5440_CPUFREQ)   += exynos5440-cpufreq.o
>  obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ)     += omap-cpufreq.o
>  obj-$(CONFIG_ARM_SPEAR_CPUFREQ)                += spear-cpufreq.o
>
> diff --git a/drivers/cpufreq/exynos5440-cpufreq.c b/drivers/cpufreq/exynos5440-cpufreq.c
> new file mode 100644
> index 0000000..41d39e2
> --- /dev/null
> +++ b/drivers/cpufreq/exynos5440-cpufreq.c
> @@ -0,0 +1,448 @@
> +/*
> + * Copyright (c) 2013 Samsung Electronics Co., Ltd.
> + *             http://www.samsung.com
> + *
> + * Amit Daniel Kachhap <amit.daniel@samsung.com>
> + *
> + * EXYNOS5440 - CPU frequency scaling support
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> +*/
> +
> +#include <linux/clk.h>
> +#include <linux/cpufreq.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/slab.h>
> +
> +/*Register definations*/
> +#define XMU_DVFS_CTRL          0x0060
> +#define XMU_PMU_P0_7           0x0064
> +#define XMU_C0_3_PSTATE        0x0090
> +#define XMU_P_LIMIT            0x00A0
> +#define XMU_P_STATUS           0x00A4
> +#define XMU_PMUEVTEN           0x00D0
> +#define XMU_PMUIRQEN           0x00D4
> +#define XMU_PMUIRQ             0x00D8
> +
> +/*PMU mask and shift definations*/
> +#define P_VALUE_MASK           0x7
> +
> +#define XMU_DVFS_CTRL_EN_SHIFT 0
> +
> +#define P0_7_CPUCLKDEV_SHIFT   21
> +#define P0_7_CPUCLKDEV_MASK    0x7
> +#define P0_7_ATBCLKDEV_SHIFT   18
> +#define P0_7_ATBCLKDEV_MASK    0x7
> +#define P0_7_CSCLKDEV_SHIFT    15
> +#define P0_7_CSCLKDEV_MASK     0x7
> +#define P0_7_CPUEMA_SHIFT      28
> +#define P0_7_CPUEMA_MASK       0xf
> +#define P0_7_L2EMA_SHIFT       24
> +#define P0_7_L2EMA_MASK        0xf
> +#define P0_7_VDD_SHIFT         8
> +#define P0_7_VDD_MASK          0x7f
> +#define P0_7_FREQ_SHIFT                0
> +#define P0_7_FREQ_MASK         0xff
> +
> +#define C0_3_PSTATE_VALID_SHIFT        8
> +#define C0_3_PSTATE_CURR_SHIFT 4
> +#define C0_3_PSTATE_NEW_SHIFT  0
> +
> +#define PSTATE_CHANGED_EVTEN_SHIFT     0
> +
> +#define PSTATE_CHANGED_IRQEN_SHIFT     0
> +
> +#define PSTATE_CHANGED_SHIFT           0
> +
> +/*some constant values for clock divider calculation*/
> +#define CPU_DIV_FREQ_MAX       500
> +#define CPU_DBG_FREQ_MAX       375
> +#define CPU_ATB_FREQ_MAX       500
> +
> +#define PMIC_LOW_VOLT          0x30
> +#define PMIC_HIGH_VOLT         0x28
> +
> +#define CPUEMA_HIGH            0x2
> +#define CPUEMA_MID             0x4
> +#define CPUEMA_LOW             0x7
> +
> +#define L2EMA_HIGH             0x1
> +#define L2EMA_MID              0x3
> +#define L2EMA_LOW              0x4
> +
> +#define DIV_TAB_MAX    2
> +/*frequency unit is 20MHZ*/
> +#define FREQ_UNIT      20
> +#define MAX_VOLTAGE    1550000 /*In micro volt*/
> +#define VOLTAGE_STEP   12500   /*In micro volt*/
> +
> +#define DRIVER_NAME            "exynos5440_dvfs"
> +#define DEF_TRANS_LATENCY      100000
> +
> +enum cpufreq_level_index {
> +       L0, L1, L2, L3, L4,
> +       L5, L6, L7, L8, L9,
> +};
> +#define CPUFREQ_LEVEL_END      (L7 + 1)
> +
> +struct exynos_dvfs_data {
> +       void __iomem *base;
> +       struct resource *mem;
> +       int irq;
> +       struct clk *cpu_clk;
> +       unsigned int cur_frequency;
> +       bool dvfs_init;
> +       struct cpufreq_frequency_table *freq_table;
> +       struct work_struct irq_work;
> +};
> +
> +static struct exynos_dvfs_data *dvfs_info;
> +static DEFINE_MUTEX(cpufreq_lock);
> +static struct cpufreq_freqs freqs;
> +static struct cpufreq_frequency_table exynos_freq_table[CPUFREQ_LEVEL_END + 1];
> +static unsigned int exynos_volt_table[CPUFREQ_LEVEL_END + 1];
> +
> +static void init_div_table(void)
> +{
> +       struct cpufreq_frequency_table *freq_tbl = exynos_freq_table;
> +       unsigned int *volt_tbl = exynos_volt_table;
> +       unsigned int tmp, clk_div, ema_div, freq, volt_id;
> +       int i = 0;
> +
> +       for (i = 0; freq_tbl[i].frequency != CPUFREQ_TABLE_END; i++) {
> +
> +               freq = freq_tbl[i].frequency / 1000; /*In MHZ*/
> +               clk_div = ((freq / CPU_DIV_FREQ_MAX) & P0_7_CPUCLKDEV_MASK)
> +                                       << P0_7_CPUCLKDEV_SHIFT;
> +               clk_div |= ((freq / CPU_ATB_FREQ_MAX) & P0_7_ATBCLKDEV_MASK)
> +                                       << P0_7_ATBCLKDEV_SHIFT;
> +               clk_div |= ((freq / CPU_DBG_FREQ_MAX) & P0_7_CSCLKDEV_MASK)
> +                                       << P0_7_CSCLKDEV_SHIFT;
> +
> +               /*Calculate EMA*/
> +               volt_id = (MAX_VOLTAGE - volt_tbl[i]) / VOLTAGE_STEP;
> +               if (volt_id < PMIC_HIGH_VOLT) {
> +                       ema_div = (CPUEMA_HIGH << P0_7_CPUEMA_SHIFT) |
> +                               (L2EMA_HIGH << P0_7_L2EMA_SHIFT);
> +               } else if (volt_id > PMIC_LOW_VOLT) {
> +                       ema_div = (CPUEMA_LOW << P0_7_CPUEMA_SHIFT) |
> +                               (L2EMA_LOW << P0_7_L2EMA_SHIFT);
> +               } else {
> +                       ema_div = (CPUEMA_MID << P0_7_CPUEMA_SHIFT) |
> +                               (L2EMA_MID << P0_7_L2EMA_SHIFT);
> +               }
> +
> +               tmp = (clk_div | ema_div | (volt_id << P0_7_VDD_SHIFT)
> +                       | ((freq / FREQ_UNIT) << P0_7_FREQ_SHIFT));
> +
> +               __raw_writel(tmp, dvfs_info->base + XMU_PMU_P0_7 + 4 * i);
> +       }
> +}
> +
> +void exynos_enable_dvfs(void)
> +{
> +       unsigned int tmp, i, cpu;
> +       struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
> +       /*Disable DVFS*/
> +       __raw_writel(0, dvfs_info->base + XMU_DVFS_CTRL);
> +
> +       /*Enable PSTATE Change Event*/
> +       tmp = __raw_readl(dvfs_info->base + XMU_PMUEVTEN);
> +       tmp |= (1 << PSTATE_CHANGED_EVTEN_SHIFT);
> +        __raw_writel(tmp, dvfs_info->base + XMU_PMUEVTEN);
> +
> +       /*Enable PSTATE Change IRQ*/
> +       tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQEN);
> +       tmp |= (1 << PSTATE_CHANGED_IRQEN_SHIFT);
> +        __raw_writel(tmp, dvfs_info->base + XMU_PMUIRQEN);
> +
> +       /*Set initial perfromance index*/
> +       for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
> +               if (freq_table[i].frequency == dvfs_info->cur_frequency)
> +                       break;
> +
> +       if (freq_table[i].frequency == CPUFREQ_TABLE_END) {
> +               pr_crit("Boot up frequency not supported\n");
> +               if (i) {
> +                       /*Assign the highest frequency*/
> +                       i = 0;
> +                       dvfs_info->cur_frequency = freq_table[i].frequency;
> +               } else {
> +                       return;
> +               }
> +       }
> +       pr_info("Setting dvfs initial frequency = %u",
> +                                               dvfs_info->cur_frequency);
> +
> +       for (cpu = 0; cpu < CONFIG_NR_CPUS; cpu++) {
> +               tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
> +               tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
> +               tmp |= (i << C0_3_PSTATE_NEW_SHIFT);
> +               __raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
> +       }
> +
> +       /*Enable DVFS*/
> +       __raw_writel(1 << XMU_DVFS_CTRL_EN_SHIFT,
> +                               dvfs_info->base + XMU_DVFS_CTRL);
> +}
> +
> +static int exynos_verify_speed(struct cpufreq_policy *policy)
> +{
> +       return cpufreq_frequency_table_verify(policy,
> +                                             dvfs_info->freq_table);
> +}
> +
> +static unsigned int exynos_getspeed(unsigned int cpu)
> +{
> +       return dvfs_info->cur_frequency;
> +}
> +
> +static int exynos_target(struct cpufreq_policy *policy,
> +                         unsigned int target_freq,
> +                         unsigned int relation)
> +{
> +       unsigned int index, old_index, tmp;
> +       int ret = 0, i;
> +       struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
> +
> +       mutex_lock(&cpufreq_lock);
> +
> +       freqs.old = dvfs_info->cur_frequency;
> +
> +       if (dvfs_info->dvfs_init == false) {
> +               ret = -EAGAIN;
> +               goto out;
> +       }
> +
> +       /*
> +        * The policy max have been changed so that we cannot get proper
> +        * old_index with cpufreq_frequency_table_target(). Thus, ignore
> +        * policy and get the index from the raw freqeuncy table.
> +        */
> +       for (old_index = 0;
> +               freq_table[old_index].frequency != CPUFREQ_TABLE_END;
> +               old_index++)
> +               if (freq_table[old_index].frequency == freqs.old)
> +                       break;
> +
> +       if (freq_table[old_index].frequency == CPUFREQ_TABLE_END) {
> +               ret = -EINVAL;
> +               goto out;
> +       }
> +
> +       if (cpufreq_frequency_table_target(policy, freq_table,
> +                                          target_freq, relation, &index)) {
> +               ret = -EINVAL;
> +               goto out;
> +       }
> +
> +       freqs.new = freq_table[index].frequency;
> +       freqs.cpu = policy->cpu;
> +
> +       for_each_cpu(freqs.cpu, policy->cpus)
> +               cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
> +
> +       /*Set the target frequency in all C0_3_PSTATE register*/
> +       for_each_cpu(i, policy->cpus) {
> +               tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
> +               tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
> +               tmp |= (index << C0_3_PSTATE_NEW_SHIFT);
> +
> +               __raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
> +       }
> +out:
> +       mutex_unlock(&cpufreq_lock);
> +       return ret;
> +}
> +
> +static void exynos_cpufreq_work(struct work_struct *work)
> +{
> +       unsigned int cur_pstate, index;
> +       struct cpufreq_policy *policy = cpufreq_cpu_get(0); /* boot CPU */
> +       struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
> +
> +       mutex_lock(&cpufreq_lock);
> +
> +       freqs.old = dvfs_info->cur_frequency;
> +
> +       cur_pstate = __raw_readl(dvfs_info->base + XMU_P_STATUS);
> +       if (cur_pstate >> C0_3_PSTATE_VALID_SHIFT & 0x1)
> +               index = (cur_pstate >> C0_3_PSTATE_CURR_SHIFT) & P_VALUE_MASK;
> +       else
> +               index = (cur_pstate >> C0_3_PSTATE_NEW_SHIFT) & P_VALUE_MASK;
> +
> +       if (index < CPUFREQ_LEVEL_END)
> +               freqs.new = freq_table[index].frequency;
> +
> +       for_each_cpu(freqs.cpu, policy->cpus)
> +               cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
> +
> +       dvfs_info->cur_frequency = freqs.new;
> +
> +       cpufreq_cpu_put(policy);
> +       mutex_unlock(&cpufreq_lock);
> +       enable_irq(dvfs_info->irq);
> +}
> +
> +static irqreturn_t exynos_cpufreq_irq(int irq, void *id)
> +{
> +       unsigned int tmp;
> +
> +       tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQ);
> +       if (tmp >> PSTATE_CHANGED_SHIFT & 0x1) {
> +               __raw_writel(tmp, dvfs_info->base + XMU_PMUIRQ);
> +
> +               if (dvfs_info->dvfs_init == true) {
> +                       disable_irq_nosync(irq);
> +                       schedule_work(&dvfs_info->irq_work);
> +               }
> +       }
> +       return IRQ_HANDLED;
> +}
> +
> +static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
> +{
> +       policy->cur = policy->min = policy->max = dvfs_info->cur_frequency;
> +
> +       cpufreq_frequency_table_get_attr(dvfs_info->freq_table, policy->cpu);
> +
> +       /* set the transition latency value */
> +       policy->cpuinfo.transition_latency = DEF_TRANS_LATENCY;

transition_latency can be provided through DT.

> +
> +       /*
> +        * EXYNOS5440 multi-core processors has 4 cores
> +        * that the frequency cannot be set independently.
> +        * Each cpu is bound to the same speed.
> +        * So the affected cpu is all of the cpus.
> +        */
> +       if (num_online_cpus() == 1) {
> +               cpumask_copy(policy->related_cpus, cpu_possible_mask);
> +               cpumask_copy(policy->cpus, cpu_online_mask);
> +       } else {
> +               policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
> +               cpumask_setall(policy->cpus);
> +       }
> +
> +       return cpufreq_frequency_table_cpuinfo(policy, dvfs_info->freq_table);
> +}
> +
> +static struct cpufreq_driver exynos_driver = {
> +       .flags          = CPUFREQ_STICKY,
> +       .verify         = exynos_verify_speed,
> +       .target         = exynos_target,
> +       .get            = exynos_getspeed,
> +       .init           = exynos_cpufreq_cpu_init,
> +       .name           = DRIVER_NAME,
> +};
> +

Since this driver is only for exynos5440, having the same names as
common exynos-cpufreq is misleading.

> +static int __init exynos_cpufreq_init(void)
> +{
> +       int ret = -EINVAL, len, i;
> +       struct device_node *np;
> +       struct cpufreq_frequency_table *freq_tbl = exynos_freq_table;
> +       unsigned int *volt_tbl = exynos_volt_table;
> +       const struct property *prop;
> +       const __be32 *val;
> +
> +       np =  of_find_compatible_node(NULL, NULL, "samsung,exynos5440-cpufreq");
> +       if (!np)
> +               return -ENODEV;
> +
> +       dvfs_info = kzalloc(sizeof(struct exynos_dvfs_data), GFP_KERNEL);
> +       if (!dvfs_info) {
> +               of_node_put(np);
> +               return -ENOMEM;
> +       }
> +
> +       dvfs_info->base = of_iomap(np, 0);
> +       if (!dvfs_info->base) {
> +               pr_err("No cpufreq memory map found\n");
> +               ret = -ENODEV;
> +               goto err_map;
> +
> +       }
> +
> +       dvfs_info->irq = irq_of_parse_and_map(np, 0);
> +
> +       if (dvfs_info->irq == 0) {
> +               pr_err("No cpufreq irq found\n");
> +               ret = -ENODEV;
> +               goto err_irq_parse;
> +       }
> +
> +       prop = of_find_property(np, "cpufreq_tbl", NULL);
> +       if (!prop || !prop->value) {
> +               pr_err("No cpufreq table found\n");
> +               ret = -ENODEV;
> +               goto err_irq_parse;
> +       }
> +
> +       len = prop->length / sizeof(u32);
> +       val = prop->value;
> +
> +       if ((len == 0) || (len / 2 > CPUFREQ_LEVEL_END)) {
> +               pr_err("Invalid cpufreq table\n");
> +               ret = -ENODEV;
> +               goto err_irq_parse;
> +       }
> +
> +       for (i = 0; i < (len / 2); i++) {
> +               freq_tbl[i].index = i;
> +               freq_tbl[i].frequency = be32_to_cpup(val++);
> +               volt_tbl[i] = be32_to_cpup(val++);
> +       }
> +
> +       freq_tbl[i].index = i;
> +       freq_tbl[i].frequency = CPUFREQ_TABLE_END;

How about using OPP library to allocate and setup freqtable ? It will
clean up this code and you wont have to have a statically allocated
exynos_freq_table.

Thanks,
Inder

> +
> +       dvfs_info->freq_table = freq_tbl;
> +
> +       dvfs_info->cpu_clk = clk_get(NULL, "armclk");
> +       if (IS_ERR(dvfs_info->cpu_clk)) {
> +               pr_err("Failed to get cpu clock\n");
> +               ret = PTR_ERR(dvfs_info->cpu_clk);
> +               goto err_irq_parse;
> +       }
> +
> +       INIT_WORK(&dvfs_info->irq_work, exynos_cpufreq_work);
> +       if (request_irq(dvfs_info->irq, exynos_cpufreq_irq,
> +                               IRQF_TRIGGER_NONE, DRIVER_NAME, dvfs_info)) {
> +               pr_err("Failed to register IRQ\n");
> +               ret = -ENODEV;
> +               goto err_irq_req;
> +       }
> +
> +       dvfs_info->cur_frequency = clk_get_rate(dvfs_info->cpu_clk) / 1000;
> +       init_div_table();
> +       exynos_enable_dvfs();
> +
> +       if (cpufreq_register_driver(&exynos_driver)) {
> +               pr_err("%s: failed to register cpufreq driver\n", __func__);
> +               goto err_register;
> +       }
> +
> +       of_node_put(np);
> +       dvfs_info->dvfs_init = true;
> +       pr_info("exynos5440 DVFS initialised.\n");
> +
> +       return 0;
> +
> +err_register:
> +       free_irq(dvfs_info->irq, dvfs_info);
> +err_irq_req:
> +       clk_put(dvfs_info->cpu_clk);
> +err_irq_parse:
> +       iounmap(dvfs_info->base);
> +err_map:
> +       of_node_put(np);
> +       kfree(dvfs_info);
> +       pr_err("%s: failed initialization\n", __func__);
> +       return -EINVAL;
> +}
> +late_initcall(exynos_cpufreq_init);
> --
> 1.7.10.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Viresh Kumar Feb. 7, 2013, 11:17 a.m. UTC | #2
On Thu, Feb 7, 2013 at 1:09 AM, Amit Daniel Kachhap
<amit.daniel@samsung.com> wrote:
> This patch adds dvfs support for exynos5440 SOC. The nature of exynos5440
> clock controller is different from previous exynos controllers so not using
> the common exynos cpufreq framework. Also, the device tree parsing is added
> to get different parameters like frequency, voltage etc.

Some information about platform cpu configuration would be helpful.. cpus, type,
clock lines for cpus - shared/separate?

> Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
> ---
>  .../bindings/cpufreq/cpufreq-exynos5440.txt        |   24 ++
>  drivers/cpufreq/Kconfig.arm                        |    8 +
>  drivers/cpufreq/Makefile                           |    1 +
>  drivers/cpufreq/exynos5440-cpufreq.c               |  448 ++++++++++++++++++++
>  4 files changed, 481 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
>  create mode 100644 drivers/cpufreq/exynos5440-cpufreq.c
>
> diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
> new file mode 100644
> index 0000000..96cb0ed
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
> @@ -0,0 +1,24 @@
> +
> +Exynos5440 cpufreq driver
> +-------------------
> +
> +Exynos5440 SoC cpufreq driver for CPU frequency scaling.
> +
> +Required properties:
> +- interrupts: Interrupt to know the completion of cpu frequency change.
> +- cpufreq_tbl: Table of frequencies and voltage CPU could be transitioned into,

This has to be "operating-points" as in cpufreq-cpu0 driver.

> +       in the decreasing order. Frequency should be in KHZ units and voltage
> +       should be in microvolts.
> +
> +All the required listed above must be defined under node cpufreq.
> +
> +Example:
> +--------
> +       cpufreq@160000 {
> +               compatible = "samsung,exynos5440-cpufreq";
> +               reg = <0x160000 0x1000>;
> +               interrupts = <0 57 0>;
> +               cpufreq_tbl = < 1200000 1025000
> +                               1000000 975000
> +                               800000  925000 >;
> +       };

> diff --git a/drivers/cpufreq/exynos5440-cpufreq.c b/drivers/cpufreq/exynos5440-cpufreq.c
> new file mode 100644
> index 0000000..41d39e2
> --- /dev/null
> +++ b/drivers/cpufreq/exynos5440-cpufreq.c
> @@ -0,0 +1,448 @@
> +/*
> + * Copyright (c) 2013 Samsung Electronics Co., Ltd.
> + *             http://www.samsung.com
> + *
> + * Amit Daniel Kachhap <amit.daniel@samsung.com>
> + *
> + * EXYNOS5440 - CPU frequency scaling support
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> +*/
> +
> +#include <linux/clk.h>
> +#include <linux/cpufreq.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/slab.h>
> +
> +/*Register definations*/
> +#define XMU_DVFS_CTRL          0x0060
> +#define XMU_PMU_P0_7           0x0064
> +#define XMU_C0_3_PSTATE        0x0090
> +#define XMU_P_LIMIT            0x00A0
> +#define XMU_P_STATUS           0x00A4
> +#define XMU_PMUEVTEN           0x00D0
> +#define XMU_PMUIRQEN           0x00D4
> +#define XMU_PMUIRQ             0x00D8
> +
> +/*PMU mask and shift definations*/
> +#define P_VALUE_MASK           0x7
> +
> +#define XMU_DVFS_CTRL_EN_SHIFT 0
> +
> +#define P0_7_CPUCLKDEV_SHIFT   21
> +#define P0_7_CPUCLKDEV_MASK    0x7
> +#define P0_7_ATBCLKDEV_SHIFT   18
> +#define P0_7_ATBCLKDEV_MASK    0x7
> +#define P0_7_CSCLKDEV_SHIFT    15
> +#define P0_7_CSCLKDEV_MASK     0x7
> +#define P0_7_CPUEMA_SHIFT      28
> +#define P0_7_CPUEMA_MASK       0xf
> +#define P0_7_L2EMA_SHIFT       24
> +#define P0_7_L2EMA_MASK        0xf
> +#define P0_7_VDD_SHIFT         8
> +#define P0_7_VDD_MASK          0x7f
> +#define P0_7_FREQ_SHIFT                0
> +#define P0_7_FREQ_MASK         0xff
> +
> +#define C0_3_PSTATE_VALID_SHIFT        8
> +#define C0_3_PSTATE_CURR_SHIFT 4
> +#define C0_3_PSTATE_NEW_SHIFT  0
> +
> +#define PSTATE_CHANGED_EVTEN_SHIFT     0
> +
> +#define PSTATE_CHANGED_IRQEN_SHIFT     0
> +
> +#define PSTATE_CHANGED_SHIFT           0
> +
> +/*some constant values for clock divider calculation*/
> +#define CPU_DIV_FREQ_MAX       500
> +#define CPU_DBG_FREQ_MAX       375
> +#define CPU_ATB_FREQ_MAX       500
> +
> +#define PMIC_LOW_VOLT          0x30
> +#define PMIC_HIGH_VOLT         0x28
> +
> +#define CPUEMA_HIGH            0x2
> +#define CPUEMA_MID             0x4
> +#define CPUEMA_LOW             0x7
> +
> +#define L2EMA_HIGH             0x1
> +#define L2EMA_MID              0x3
> +#define L2EMA_LOW              0x4
> +
> +#define DIV_TAB_MAX    2
> +/*frequency unit is 20MHZ*/
> +#define FREQ_UNIT      20
> +#define MAX_VOLTAGE    1550000 /*In micro volt*/
> +#define VOLTAGE_STEP   12500   /*In micro volt*/
> +
> +#define DRIVER_NAME            "exynos5440_dvfs"
> +#define DEF_TRANS_LATENCY      100000
> +
> +enum cpufreq_level_index {
> +       L0, L1, L2, L3, L4,
> +       L5, L6, L7, L8, L9,
> +};
> +#define CPUFREQ_LEVEL_END      (L7 + 1)
> +
> +struct exynos_dvfs_data {
> +       void __iomem *base;
> +       struct resource *mem;
> +       int irq;
> +       struct clk *cpu_clk;
> +       unsigned int cur_frequency;
> +       bool dvfs_init;
> +       struct cpufreq_frequency_table *freq_table;
> +       struct work_struct irq_work;
> +};
> +
> +static struct exynos_dvfs_data *dvfs_info;
> +static DEFINE_MUTEX(cpufreq_lock);
> +static struct cpufreq_freqs freqs;
> +static struct cpufreq_frequency_table exynos_freq_table[CPUFREQ_LEVEL_END + 1];
> +static unsigned int exynos_volt_table[CPUFREQ_LEVEL_END + 1];
> +
> +static void init_div_table(void)
> +{
> +       struct cpufreq_frequency_table *freq_tbl = exynos_freq_table;
> +       unsigned int *volt_tbl = exynos_volt_table;
> +       unsigned int tmp, clk_div, ema_div, freq, volt_id;
> +       int i = 0;
> +
> +       for (i = 0; freq_tbl[i].frequency != CPUFREQ_TABLE_END; i++) {
> +
> +               freq = freq_tbl[i].frequency / 1000; /*In MHZ*/
> +               clk_div = ((freq / CPU_DIV_FREQ_MAX) & P0_7_CPUCLKDEV_MASK)
> +                                       << P0_7_CPUCLKDEV_SHIFT;
> +               clk_div |= ((freq / CPU_ATB_FREQ_MAX) & P0_7_ATBCLKDEV_MASK)
> +                                       << P0_7_ATBCLKDEV_SHIFT;
> +               clk_div |= ((freq / CPU_DBG_FREQ_MAX) & P0_7_CSCLKDEV_MASK)
> +                                       << P0_7_CSCLKDEV_SHIFT;
> +
> +               /*Calculate EMA*/
> +               volt_id = (MAX_VOLTAGE - volt_tbl[i]) / VOLTAGE_STEP;
> +               if (volt_id < PMIC_HIGH_VOLT) {
> +                       ema_div = (CPUEMA_HIGH << P0_7_CPUEMA_SHIFT) |
> +                               (L2EMA_HIGH << P0_7_L2EMA_SHIFT);
> +               } else if (volt_id > PMIC_LOW_VOLT) {
> +                       ema_div = (CPUEMA_LOW << P0_7_CPUEMA_SHIFT) |
> +                               (L2EMA_LOW << P0_7_L2EMA_SHIFT);
> +               } else {
> +                       ema_div = (CPUEMA_MID << P0_7_CPUEMA_SHIFT) |
> +                               (L2EMA_MID << P0_7_L2EMA_SHIFT);
> +               }
> +
> +               tmp = (clk_div | ema_div | (volt_id << P0_7_VDD_SHIFT)
> +                       | ((freq / FREQ_UNIT) << P0_7_FREQ_SHIFT));
> +
> +               __raw_writel(tmp, dvfs_info->base + XMU_PMU_P0_7 + 4 * i);
> +       }
> +}
> +
> +void exynos_enable_dvfs(void)
> +{
> +       unsigned int tmp, i, cpu;
> +       struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
> +       /*Disable DVFS*/
> +       __raw_writel(0, dvfs_info->base + XMU_DVFS_CTRL);
> +
> +       /*Enable PSTATE Change Event*/
> +       tmp = __raw_readl(dvfs_info->base + XMU_PMUEVTEN);
> +       tmp |= (1 << PSTATE_CHANGED_EVTEN_SHIFT);
> +        __raw_writel(tmp, dvfs_info->base + XMU_PMUEVTEN);
> +
> +       /*Enable PSTATE Change IRQ*/
> +       tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQEN);
> +       tmp |= (1 << PSTATE_CHANGED_IRQEN_SHIFT);
> +        __raw_writel(tmp, dvfs_info->base + XMU_PMUIRQEN);
> +
> +       /*Set initial perfromance index*/

performance.

> +       for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
> +               if (freq_table[i].frequency == dvfs_info->cur_frequency)
> +                       break;
> +
> +       if (freq_table[i].frequency == CPUFREQ_TABLE_END) {
> +               pr_crit("Boot up frequency not supported\n");
> +               if (i) {
> +                       /*Assign the highest frequency*/
> +                       i = 0;
> +                       dvfs_info->cur_frequency = freq_table[i].frequency;
> +               } else {
> +                       return;
> +               }
> +       }
> +       pr_info("Setting dvfs initial frequency = %u",
> +                                               dvfs_info->cur_frequency);
> +
> +       for (cpu = 0; cpu < CONFIG_NR_CPUS; cpu++) {
> +               tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
> +               tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
> +               tmp |= (i << C0_3_PSTATE_NEW_SHIFT);
> +               __raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
> +       }
> +
> +       /*Enable DVFS*/
> +       __raw_writel(1 << XMU_DVFS_CTRL_EN_SHIFT,
> +                               dvfs_info->base + XMU_DVFS_CTRL);
> +}
> +
> +static int exynos_verify_speed(struct cpufreq_policy *policy)
> +{
> +       return cpufreq_frequency_table_verify(policy,
> +                                             dvfs_info->freq_table);
> +}
> +
> +static unsigned int exynos_getspeed(unsigned int cpu)
> +{
> +       return dvfs_info->cur_frequency;
> +}
> +
> +static int exynos_target(struct cpufreq_policy *policy,
> +                         unsigned int target_freq,
> +                         unsigned int relation)
> +{
> +       unsigned int index, old_index, tmp;
> +       int ret = 0, i;
> +       struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
> +
> +       mutex_lock(&cpufreq_lock);
> +
> +       freqs.old = dvfs_info->cur_frequency;
> +
> +       if (dvfs_info->dvfs_init == false) {
> +               ret = -EAGAIN;
> +               goto out;
> +       }
> +
> +       /*
> +        * The policy max have been changed so that we cannot get proper
> +        * old_index with cpufreq_frequency_table_target(). Thus, ignore
> +        * policy and get the index from the raw freqeuncy table.
> +        */

What? Why ?

> +       for (old_index = 0;
> +               freq_table[old_index].frequency != CPUFREQ_TABLE_END;
> +               old_index++)
> +               if (freq_table[old_index].frequency == freqs.old)
> +                       break;
> +
> +       if (freq_table[old_index].frequency == CPUFREQ_TABLE_END) {

How can this be true?

> +               ret = -EINVAL;
> +               goto out;
> +       }
> +
> +       if (cpufreq_frequency_table_target(policy, freq_table,
> +                                          target_freq, relation, &index)) {
> +               ret = -EINVAL;
> +               goto out;
> +       }
> +
> +       freqs.new = freq_table[index].frequency;
> +       freqs.cpu = policy->cpu;
> +
> +       for_each_cpu(freqs.cpu, policy->cpus)
> +               cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
> +
> +       /*Set the target frequency in all C0_3_PSTATE register*/
> +       for_each_cpu(i, policy->cpus) {
> +               tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
> +               tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
> +               tmp |= (index << C0_3_PSTATE_NEW_SHIFT);
> +
> +               __raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
> +       }
> +out:
> +       mutex_unlock(&cpufreq_lock);

That's something new and interesting. So you are just configuring your
controller
for a new dvfs point and get back to work. Then you would get an
interrupt sometime
and work is queued and everybody notified.

@Rafael: You expect any issue with this technique ?

> +       return ret;
> +}
> +
> +static void exynos_cpufreq_work(struct work_struct *work)
> +{
> +       unsigned int cur_pstate, index;
> +       struct cpufreq_policy *policy = cpufreq_cpu_get(0); /* boot CPU */
> +       struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
> +
> +       mutex_lock(&cpufreq_lock);
> +
> +       freqs.old = dvfs_info->cur_frequency;
> +
> +       cur_pstate = __raw_readl(dvfs_info->base + XMU_P_STATUS);
> +       if (cur_pstate >> C0_3_PSTATE_VALID_SHIFT & 0x1)
> +               index = (cur_pstate >> C0_3_PSTATE_CURR_SHIFT) & P_VALUE_MASK;
> +       else
> +               index = (cur_pstate >> C0_3_PSTATE_NEW_SHIFT) & P_VALUE_MASK;
> +
> +       if (index < CPUFREQ_LEVEL_END)
> +               freqs.new = freq_table[index].frequency;
> +
> +       for_each_cpu(freqs.cpu, policy->cpus)
> +               cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
> +
> +       dvfs_info->cur_frequency = freqs.new;
> +
> +       cpufreq_cpu_put(policy);
> +       mutex_unlock(&cpufreq_lock);
> +       enable_irq(dvfs_info->irq);
> +}
> +
> +static irqreturn_t exynos_cpufreq_irq(int irq, void *id)
> +{
> +       unsigned int tmp;
> +
> +       tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQ);
> +       if (tmp >> PSTATE_CHANGED_SHIFT & 0x1) {
> +               __raw_writel(tmp, dvfs_info->base + XMU_PMUIRQ);
> +
> +               if (dvfs_info->dvfs_init == true) {
> +                       disable_irq_nosync(irq);
> +                       schedule_work(&dvfs_info->irq_work);
> +               }
> +       }
> +       return IRQ_HANDLED;
> +}
> +
> +static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
> +{
> +       policy->cur = policy->min = policy->max = dvfs_info->cur_frequency;

you don't have to fill min and max. its done by core when you call
cpufreq_frequency_table_cpuinfo().

> +
> +       cpufreq_frequency_table_get_attr(dvfs_info->freq_table, policy->cpu);
> +
> +       /* set the transition latency value */
> +       policy->cpuinfo.transition_latency = DEF_TRANS_LATENCY;
> +
> +       /*
> +        * EXYNOS5440 multi-core processors has 4 cores
> +        * that the frequency cannot be set independently.
> +        * Each cpu is bound to the same speed.
> +        * So the affected cpu is all of the cpus.
> +        */

Good. I understood it now :)

> +       if (num_online_cpus() == 1) {
> +               cpumask_copy(policy->related_cpus, cpu_possible_mask);
> +               cpumask_copy(policy->cpus, cpu_online_mask);
> +       } else {
> +               policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
> +               cpumask_setall(policy->cpus);
> +       }

Replace everything between "Good" and this line with:

cpumask_setall(policy->cpus);

http://www.spinics.net/lists/cpufreq/msg04091.html

> +       return cpufreq_frequency_table_cpuinfo(policy, dvfs_info->freq_table);
> +}
> +
> +static struct cpufreq_driver exynos_driver = {
> +       .flags          = CPUFREQ_STICKY,
> +       .verify         = exynos_verify_speed,
> +       .target         = exynos_target,
> +       .get            = exynos_getspeed,
> +       .init           = exynos_cpufreq_cpu_init,
> +       .name           = DRIVER_NAME,
> +};
> +
> +static int __init exynos_cpufreq_init(void)
> +{
> +       int ret = -EINVAL, len, i;
> +       struct device_node *np;
> +       struct cpufreq_frequency_table *freq_tbl = exynos_freq_table;
> +       unsigned int *volt_tbl = exynos_volt_table;

why do we need duplicate names for global variables here? remove exynos_
from globals and that would be enough (in case you don't want long names).

> +       const struct property *prop;
> +       const __be32 *val;
> +
> +       np =  of_find_compatible_node(NULL, NULL, "samsung,exynos5440-cpufreq");
> +       if (!np)
> +               return -ENODEV;
> +
> +       dvfs_info = kzalloc(sizeof(struct exynos_dvfs_data), GFP_KERNEL);

sizeof(*dvfs_info) ?? why don't make it static too, as you have other
stuff too.. ?
The better option for single image solution to allocate everything
dynamically, so that
unused drivers don't occupy any space.

> +       if (!dvfs_info) {
> +               of_node_put(np);
> +               return -ENOMEM;
> +       }
> +
> +       dvfs_info->base = of_iomap(np, 0);
> +       if (!dvfs_info->base) {
> +               pr_err("No cpufreq memory map found\n");
> +               ret = -ENODEV;
> +               goto err_map;
> +
> +       }
> +
> +       dvfs_info->irq = irq_of_parse_and_map(np, 0);
> +
> +       if (dvfs_info->irq == 0) {
> +               pr_err("No cpufreq irq found\n");
> +               ret = -ENODEV;
> +               goto err_irq_parse;
> +       }
> +
> +       prop = of_find_property(np, "cpufreq_tbl", NULL);
> +       if (!prop || !prop->value) {
> +               pr_err("No cpufreq table found\n");
> +               ret = -ENODEV;
> +               goto err_irq_parse;
> +       }
> +
> +       len = prop->length / sizeof(u32);
> +       val = prop->value;
> +
> +       if ((len == 0) || (len / 2 > CPUFREQ_LEVEL_END)) {

I really didn't like this limit you have put at the number of dvfs
points. Better
would be to use:

	ret = of_init_opp_table(cpu_dev);
	if (ret) {
		pr_err("failed to init OPP table: %d\n", ret);
		goto out_put_node;
	}

	ret = opp_init_cpufreq_table(cpu_dev, &freq_table);
	if (ret) {
		pr_err("failed to init cpufreq table: %d\n", ret);
		goto out_put_node;
	}

as used in cpufreq-cpu0 driver. Also please have a closer look at this driver,
you may not your driver at all :)

> +               pr_err("Invalid cpufreq table\n");
> +               ret = -ENODEV;
> +               goto err_irq_parse;
> +       }
> +
> +       for (i = 0; i < (len / 2); i++) {
> +               freq_tbl[i].index = i;
> +               freq_tbl[i].frequency = be32_to_cpup(val++);
> +               volt_tbl[i] = be32_to_cpup(val++);
> +       }
> +
> +       freq_tbl[i].index = i;
> +       freq_tbl[i].frequency = CPUFREQ_TABLE_END;
> +
> +       dvfs_info->freq_table = freq_tbl;
> +
> +       dvfs_info->cpu_clk = clk_get(NULL, "armclk");

devm_clk_get() ?

> +       if (IS_ERR(dvfs_info->cpu_clk)) {
> +               pr_err("Failed to get cpu clock\n");
> +               ret = PTR_ERR(dvfs_info->cpu_clk);
> +               goto err_irq_parse;
> +       }
> +
> +       INIT_WORK(&dvfs_info->irq_work, exynos_cpufreq_work);
> +       if (request_irq(dvfs_info->irq, exynos_cpufreq_irq,

devm_ ??

> +                               IRQF_TRIGGER_NONE, DRIVER_NAME, dvfs_info)) {
> +               pr_err("Failed to register IRQ\n");
> +               ret = -ENODEV;
> +               goto err_irq_req;
> +       }
> +
> +       dvfs_info->cur_frequency = clk_get_rate(dvfs_info->cpu_clk) / 1000;

what if clk_get_rate fails ? or returns zero.

> +       init_div_table();
> +       exynos_enable_dvfs();
> +
> +       if (cpufreq_register_driver(&exynos_driver)) {
> +               pr_err("%s: failed to register cpufreq driver\n", __func__);
> +               goto err_register;
> +       }
> +
> +       of_node_put(np);
> +       dvfs_info->dvfs_init = true;

why do you need this ?

> +       pr_info("exynos5440 DVFS initialised.\n");
> +
> +       return 0;
> +
> +err_register:
> +       free_irq(dvfs_info->irq, dvfs_info);
> +err_irq_req:
> +       clk_put(dvfs_info->cpu_clk);
> +err_irq_parse:
> +       iounmap(dvfs_info->base);
> +err_map:
> +       of_node_put(np);
> +       kfree(dvfs_info);
> +       pr_err("%s: failed initialization\n", __func__);
> +       return -EINVAL;
> +}
> +late_initcall(exynos_cpufreq_init);
> --
> 1.7.10.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Viresh Kumar Feb. 7, 2013, 11:19 a.m. UTC | #3
On Thu, Feb 7, 2013 at 10:39 AM, Inderpal Singh
<inderpal.singh@linaro.org> wrote:
>> +#define DRIVER_NAME            "exynos5440_dvfs"

>> +static struct cpufreq_driver exynos_driver = {
>> +       .name           = DRIVER_NAME,
>> +};
>> +
>
> Since this driver is only for exynos5440, having the same names as
> common exynos-cpufreq is misleading.

Where is it same?
--
To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Inderpal Singh Feb. 7, 2013, 11:28 a.m. UTC | #4
On 7 February 2013 16:49, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> On Thu, Feb 7, 2013 at 10:39 AM, Inderpal Singh
> <inderpal.singh@linaro.org> wrote:
>>> +#define DRIVER_NAME            "exynos5440_dvfs"
>
>>> +static struct cpufreq_driver exynos_driver = {
>>> +       .name           = DRIVER_NAME,
>>> +};
>>> +
>>
>> Since this driver is only for exynos5440, having the same names as
>> common exynos-cpufreq is misleading.
>
> Where is it same?

I meant hooks names (verify/get/target and init)

Thanks,
Inder
--
To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
amit kachhap Feb. 7, 2013, 6:39 p.m. UTC | #5
Hi Inder,

Thanks for the review,
On Wed, Feb 6, 2013 at 9:09 PM, Inderpal Singh
<inderpal.singh@linaro.org> wrote:
> On 7 February 2013 01:09, Amit Daniel Kachhap <amit.daniel@samsung.com> wrote:
>> This patch adds dvfs support for exynos5440 SOC. The nature of exynos5440
>> clock controller is different from previous exynos controllers so not using
>> the common exynos cpufreq framework. Also, the device tree parsing is added
>> to get different parameters like frequency, voltage etc.
>>
>> Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
>> ---
>>  .../bindings/cpufreq/cpufreq-exynos5440.txt        |   24 ++
>>  drivers/cpufreq/Kconfig.arm                        |    8 +
>>  drivers/cpufreq/Makefile                           |    1 +
>>  drivers/cpufreq/exynos5440-cpufreq.c               |  448 ++++++++++++++++++++
>>  4 files changed, 481 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
>>  create mode 100644 drivers/cpufreq/exynos5440-cpufreq.c
>>
>> diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
>> new file mode 100644
>> index 0000000..96cb0ed
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
>> @@ -0,0 +1,24 @@
>> +
>> +Exynos5440 cpufreq driver
>> +-------------------
>> +
>> +Exynos5440 SoC cpufreq driver for CPU frequency scaling.
>> +
>> +Required properties:
>> +- interrupts: Interrupt to know the completion of cpu frequency change.
>> +- cpufreq_tbl: Table of frequencies and voltage CPU could be transitioned into,
>> +       in the decreasing order. Frequency should be in KHZ units and voltage
>> +       should be in microvolts.
>> +
>> +All the required listed above must be defined under node cpufreq.
>> +
>> +Example:
>> +--------
>> +       cpufreq@160000 {
>> +               compatible = "samsung,exynos5440-cpufreq";
>> +               reg = <0x160000 0x1000>;
>> +               interrupts = <0 57 0>;
>> +               cpufreq_tbl = < 1200000 1025000
>> +                               1000000 975000
>> +                               800000  925000 >;
>> +       };
>> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
>> index a0b3661..554756f 100644
>> --- a/drivers/cpufreq/Kconfig.arm
>> +++ b/drivers/cpufreq/Kconfig.arm
>> @@ -77,6 +77,14 @@ config ARM_EXYNOS5250_CPUFREQ
>>           This adds the CPUFreq driver for Samsung EXYNOS5250
>>           SoC.
>>
>> +config ARM_EXYNOS5440_CPUFREQ
>> +       def_bool SOC_EXYNOS5440
>> +       help
>> +         This adds the CPUFreq driver for Samsung EXYNOS5440
>> +         SoC. The nature of exynos5440 clock controller is
>> +         different than previous exynos controllers so not using
>> +         the common exynos framework.
>> +
>>  config ARM_SPEAR_CPUFREQ
>>         bool "SPEAr CPUFreq support"
>>         depends on PLAT_SPEAR
>> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
>> index fadc4d4..5159ba4 100644
>> --- a/drivers/cpufreq/Makefile
>> +++ b/drivers/cpufreq/Makefile
>> @@ -50,6 +50,7 @@ obj-$(CONFIG_ARM_EXYNOS_CPUFREQ)      += exynos-cpufreq.o
>>  obj-$(CONFIG_ARM_EXYNOS4210_CPUFREQ)   += exynos4210-cpufreq.o
>>  obj-$(CONFIG_ARM_EXYNOS4X12_CPUFREQ)   += exynos4x12-cpufreq.o
>>  obj-$(CONFIG_ARM_EXYNOS5250_CPUFREQ)   += exynos5250-cpufreq.o
>> +obj-$(CONFIG_ARM_EXYNOS5440_CPUFREQ)   += exynos5440-cpufreq.o
>>  obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ)     += omap-cpufreq.o
>>  obj-$(CONFIG_ARM_SPEAR_CPUFREQ)                += spear-cpufreq.o
>>
>> diff --git a/drivers/cpufreq/exynos5440-cpufreq.c b/drivers/cpufreq/exynos5440-cpufreq.c
>> new file mode 100644
>> index 0000000..41d39e2
>> --- /dev/null
>> +++ b/drivers/cpufreq/exynos5440-cpufreq.c
>> @@ -0,0 +1,448 @@
>> +/*
>> + * Copyright (c) 2013 Samsung Electronics Co., Ltd.
>> + *             http://www.samsung.com
>> + *
>> + * Amit Daniel Kachhap <amit.daniel@samsung.com>
>> + *
>> + * EXYNOS5440 - CPU frequency scaling support
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> +*/
>> +
>> +#include <linux/clk.h>
>> +#include <linux/cpufreq.h>
>> +#include <linux/err.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/io.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_irq.h>
>> +#include <linux/slab.h>
>> +
>> +/*Register definations*/
>> +#define XMU_DVFS_CTRL          0x0060
>> +#define XMU_PMU_P0_7           0x0064
>> +#define XMU_C0_3_PSTATE        0x0090
>> +#define XMU_P_LIMIT            0x00A0
>> +#define XMU_P_STATUS           0x00A4
>> +#define XMU_PMUEVTEN           0x00D0
>> +#define XMU_PMUIRQEN           0x00D4
>> +#define XMU_PMUIRQ             0x00D8
>> +
>> +/*PMU mask and shift definations*/
>> +#define P_VALUE_MASK           0x7
>> +
>> +#define XMU_DVFS_CTRL_EN_SHIFT 0
>> +
>> +#define P0_7_CPUCLKDEV_SHIFT   21
>> +#define P0_7_CPUCLKDEV_MASK    0x7
>> +#define P0_7_ATBCLKDEV_SHIFT   18
>> +#define P0_7_ATBCLKDEV_MASK    0x7
>> +#define P0_7_CSCLKDEV_SHIFT    15
>> +#define P0_7_CSCLKDEV_MASK     0x7
>> +#define P0_7_CPUEMA_SHIFT      28
>> +#define P0_7_CPUEMA_MASK       0xf
>> +#define P0_7_L2EMA_SHIFT       24
>> +#define P0_7_L2EMA_MASK        0xf
>> +#define P0_7_VDD_SHIFT         8
>> +#define P0_7_VDD_MASK          0x7f
>> +#define P0_7_FREQ_SHIFT                0
>> +#define P0_7_FREQ_MASK         0xff
>> +
>> +#define C0_3_PSTATE_VALID_SHIFT        8
>> +#define C0_3_PSTATE_CURR_SHIFT 4
>> +#define C0_3_PSTATE_NEW_SHIFT  0
>> +
>> +#define PSTATE_CHANGED_EVTEN_SHIFT     0
>> +
>> +#define PSTATE_CHANGED_IRQEN_SHIFT     0
>> +
>> +#define PSTATE_CHANGED_SHIFT           0
>> +
>> +/*some constant values for clock divider calculation*/
>> +#define CPU_DIV_FREQ_MAX       500
>> +#define CPU_DBG_FREQ_MAX       375
>> +#define CPU_ATB_FREQ_MAX       500
>> +
>> +#define PMIC_LOW_VOLT          0x30
>> +#define PMIC_HIGH_VOLT         0x28
>> +
>> +#define CPUEMA_HIGH            0x2
>> +#define CPUEMA_MID             0x4
>> +#define CPUEMA_LOW             0x7
>> +
>> +#define L2EMA_HIGH             0x1
>> +#define L2EMA_MID              0x3
>> +#define L2EMA_LOW              0x4
>> +
>> +#define DIV_TAB_MAX    2
>> +/*frequency unit is 20MHZ*/
>> +#define FREQ_UNIT      20
>> +#define MAX_VOLTAGE    1550000 /*In micro volt*/
>> +#define VOLTAGE_STEP   12500   /*In micro volt*/
>> +
>> +#define DRIVER_NAME            "exynos5440_dvfs"
>> +#define DEF_TRANS_LATENCY      100000
>> +
>> +enum cpufreq_level_index {
>> +       L0, L1, L2, L3, L4,
>> +       L5, L6, L7, L8, L9,
>> +};
>> +#define CPUFREQ_LEVEL_END      (L7 + 1)
>> +
>> +struct exynos_dvfs_data {
>> +       void __iomem *base;
>> +       struct resource *mem;
>> +       int irq;
>> +       struct clk *cpu_clk;
>> +       unsigned int cur_frequency;
>> +       bool dvfs_init;
>> +       struct cpufreq_frequency_table *freq_table;
>> +       struct work_struct irq_work;
>> +};
>> +
>> +static struct exynos_dvfs_data *dvfs_info;
>> +static DEFINE_MUTEX(cpufreq_lock);
>> +static struct cpufreq_freqs freqs;
>> +static struct cpufreq_frequency_table exynos_freq_table[CPUFREQ_LEVEL_END + 1];
>> +static unsigned int exynos_volt_table[CPUFREQ_LEVEL_END + 1];
>> +
>> +static void init_div_table(void)
>> +{
>> +       struct cpufreq_frequency_table *freq_tbl = exynos_freq_table;
>> +       unsigned int *volt_tbl = exynos_volt_table;
>> +       unsigned int tmp, clk_div, ema_div, freq, volt_id;
>> +       int i = 0;
>> +
>> +       for (i = 0; freq_tbl[i].frequency != CPUFREQ_TABLE_END; i++) {
>> +
>> +               freq = freq_tbl[i].frequency / 1000; /*In MHZ*/
>> +               clk_div = ((freq / CPU_DIV_FREQ_MAX) & P0_7_CPUCLKDEV_MASK)
>> +                                       << P0_7_CPUCLKDEV_SHIFT;
>> +               clk_div |= ((freq / CPU_ATB_FREQ_MAX) & P0_7_ATBCLKDEV_MASK)
>> +                                       << P0_7_ATBCLKDEV_SHIFT;
>> +               clk_div |= ((freq / CPU_DBG_FREQ_MAX) & P0_7_CSCLKDEV_MASK)
>> +                                       << P0_7_CSCLKDEV_SHIFT;
>> +
>> +               /*Calculate EMA*/
>> +               volt_id = (MAX_VOLTAGE - volt_tbl[i]) / VOLTAGE_STEP;
>> +               if (volt_id < PMIC_HIGH_VOLT) {
>> +                       ema_div = (CPUEMA_HIGH << P0_7_CPUEMA_SHIFT) |
>> +                               (L2EMA_HIGH << P0_7_L2EMA_SHIFT);
>> +               } else if (volt_id > PMIC_LOW_VOLT) {
>> +                       ema_div = (CPUEMA_LOW << P0_7_CPUEMA_SHIFT) |
>> +                               (L2EMA_LOW << P0_7_L2EMA_SHIFT);
>> +               } else {
>> +                       ema_div = (CPUEMA_MID << P0_7_CPUEMA_SHIFT) |
>> +                               (L2EMA_MID << P0_7_L2EMA_SHIFT);
>> +               }
>> +
>> +               tmp = (clk_div | ema_div | (volt_id << P0_7_VDD_SHIFT)
>> +                       | ((freq / FREQ_UNIT) << P0_7_FREQ_SHIFT));
>> +
>> +               __raw_writel(tmp, dvfs_info->base + XMU_PMU_P0_7 + 4 * i);
>> +       }
>> +}
>> +
>> +void exynos_enable_dvfs(void)
>> +{
>> +       unsigned int tmp, i, cpu;
>> +       struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
>> +       /*Disable DVFS*/
>> +       __raw_writel(0, dvfs_info->base + XMU_DVFS_CTRL);
>> +
>> +       /*Enable PSTATE Change Event*/
>> +       tmp = __raw_readl(dvfs_info->base + XMU_PMUEVTEN);
>> +       tmp |= (1 << PSTATE_CHANGED_EVTEN_SHIFT);
>> +        __raw_writel(tmp, dvfs_info->base + XMU_PMUEVTEN);
>> +
>> +       /*Enable PSTATE Change IRQ*/
>> +       tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQEN);
>> +       tmp |= (1 << PSTATE_CHANGED_IRQEN_SHIFT);
>> +        __raw_writel(tmp, dvfs_info->base + XMU_PMUIRQEN);
>> +
>> +       /*Set initial perfromance index*/
>> +       for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
>> +               if (freq_table[i].frequency == dvfs_info->cur_frequency)
>> +                       break;
>> +
>> +       if (freq_table[i].frequency == CPUFREQ_TABLE_END) {
>> +               pr_crit("Boot up frequency not supported\n");
>> +               if (i) {
>> +                       /*Assign the highest frequency*/
>> +                       i = 0;
>> +                       dvfs_info->cur_frequency = freq_table[i].frequency;
>> +               } else {
>> +                       return;
>> +               }
>> +       }
>> +       pr_info("Setting dvfs initial frequency = %u",
>> +                                               dvfs_info->cur_frequency);
>> +
>> +       for (cpu = 0; cpu < CONFIG_NR_CPUS; cpu++) {
>> +               tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
>> +               tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
>> +               tmp |= (i << C0_3_PSTATE_NEW_SHIFT);
>> +               __raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
>> +       }
>> +
>> +       /*Enable DVFS*/
>> +       __raw_writel(1 << XMU_DVFS_CTRL_EN_SHIFT,
>> +                               dvfs_info->base + XMU_DVFS_CTRL);
>> +}
>> +
>> +static int exynos_verify_speed(struct cpufreq_policy *policy)
>> +{
>> +       return cpufreq_frequency_table_verify(policy,
>> +                                             dvfs_info->freq_table);
>> +}
>> +
>> +static unsigned int exynos_getspeed(unsigned int cpu)
>> +{
>> +       return dvfs_info->cur_frequency;
>> +}
>> +
>> +static int exynos_target(struct cpufreq_policy *policy,
>> +                         unsigned int target_freq,
>> +                         unsigned int relation)
>> +{
>> +       unsigned int index, old_index, tmp;
>> +       int ret = 0, i;
>> +       struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
>> +
>> +       mutex_lock(&cpufreq_lock);
>> +
>> +       freqs.old = dvfs_info->cur_frequency;
>> +
>> +       if (dvfs_info->dvfs_init == false) {
>> +               ret = -EAGAIN;
>> +               goto out;
>> +       }
>> +
>> +       /*
>> +        * The policy max have been changed so that we cannot get proper
>> +        * old_index with cpufreq_frequency_table_target(). Thus, ignore
>> +        * policy and get the index from the raw freqeuncy table.
>> +        */
>> +       for (old_index = 0;
>> +               freq_table[old_index].frequency != CPUFREQ_TABLE_END;
>> +               old_index++)
>> +               if (freq_table[old_index].frequency == freqs.old)
>> +                       break;
>> +
>> +       if (freq_table[old_index].frequency == CPUFREQ_TABLE_END) {
>> +               ret = -EINVAL;
>> +               goto out;
>> +       }
>> +
>> +       if (cpufreq_frequency_table_target(policy, freq_table,
>> +                                          target_freq, relation, &index)) {
>> +               ret = -EINVAL;
>> +               goto out;
>> +       }
>> +
>> +       freqs.new = freq_table[index].frequency;
>> +       freqs.cpu = policy->cpu;
>> +
>> +       for_each_cpu(freqs.cpu, policy->cpus)
>> +               cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
>> +
>> +       /*Set the target frequency in all C0_3_PSTATE register*/
>> +       for_each_cpu(i, policy->cpus) {
>> +               tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
>> +               tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
>> +               tmp |= (index << C0_3_PSTATE_NEW_SHIFT);
>> +
>> +               __raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
>> +       }
>> +out:
>> +       mutex_unlock(&cpufreq_lock);
>> +       return ret;
>> +}
>> +
>> +static void exynos_cpufreq_work(struct work_struct *work)
>> +{
>> +       unsigned int cur_pstate, index;
>> +       struct cpufreq_policy *policy = cpufreq_cpu_get(0); /* boot CPU */
>> +       struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
>> +
>> +       mutex_lock(&cpufreq_lock);
>> +
>> +       freqs.old = dvfs_info->cur_frequency;
>> +
>> +       cur_pstate = __raw_readl(dvfs_info->base + XMU_P_STATUS);
>> +       if (cur_pstate >> C0_3_PSTATE_VALID_SHIFT & 0x1)
>> +               index = (cur_pstate >> C0_3_PSTATE_CURR_SHIFT) & P_VALUE_MASK;
>> +       else
>> +               index = (cur_pstate >> C0_3_PSTATE_NEW_SHIFT) & P_VALUE_MASK;
>> +
>> +       if (index < CPUFREQ_LEVEL_END)
>> +               freqs.new = freq_table[index].frequency;
>> +
>> +       for_each_cpu(freqs.cpu, policy->cpus)
>> +               cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
>> +
>> +       dvfs_info->cur_frequency = freqs.new;
>> +
>> +       cpufreq_cpu_put(policy);
>> +       mutex_unlock(&cpufreq_lock);
>> +       enable_irq(dvfs_info->irq);
>> +}
>> +
>> +static irqreturn_t exynos_cpufreq_irq(int irq, void *id)
>> +{
>> +       unsigned int tmp;
>> +
>> +       tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQ);
>> +       if (tmp >> PSTATE_CHANGED_SHIFT & 0x1) {
>> +               __raw_writel(tmp, dvfs_info->base + XMU_PMUIRQ);
>> +
>> +               if (dvfs_info->dvfs_init == true) {
>> +                       disable_irq_nosync(irq);
>> +                       schedule_work(&dvfs_info->irq_work);
>> +               }
>> +       }
>> +       return IRQ_HANDLED;
>> +}
>> +
>> +static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
>> +{
>> +       policy->cur = policy->min = policy->max = dvfs_info->cur_frequency;
>> +
>> +       cpufreq_frequency_table_get_attr(dvfs_info->freq_table, policy->cpu);
>> +
>> +       /* set the transition latency value */
>> +       policy->cpuinfo.transition_latency = DEF_TRANS_LATENCY;
>
> transition_latency can be provided through DT.
Yes I also thought but all previous exynos cpufreq driver uses the
same constant value so didn't create dt node.
>
>> +
>> +       /*
>> +        * EXYNOS5440 multi-core processors has 4 cores
>> +        * that the frequency cannot be set independently.
>> +        * Each cpu is bound to the same speed.
>> +        * So the affected cpu is all of the cpus.
>> +        */
>> +       if (num_online_cpus() == 1) {
>> +               cpumask_copy(policy->related_cpus, cpu_possible_mask);
>> +               cpumask_copy(policy->cpus, cpu_online_mask);
>> +       } else {
>> +               policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
>> +               cpumask_setall(policy->cpus);
>> +       }
>> +
>> +       return cpufreq_frequency_table_cpuinfo(policy, dvfs_info->freq_table);
>> +}
>> +
>> +static struct cpufreq_driver exynos_driver = {
>> +       .flags          = CPUFREQ_STICKY,
>> +       .verify         = exynos_verify_speed,
>> +       .target         = exynos_target,
>> +       .get            = exynos_getspeed,
>> +       .init           = exynos_cpufreq_cpu_init,
>> +       .name           = DRIVER_NAME,
>> +};
>> +
>
> Since this driver is only for exynos5440, having the same names as
> common exynos-cpufreq is misleading.
Yes your suggestion is good but the names like exynos5440_* looks very long.
>
>> +static int __init exynos_cpufreq_init(void)
>> +{
>> +       int ret = -EINVAL, len, i;
>> +       struct device_node *np;
>> +       struct cpufreq_frequency_table *freq_tbl = exynos_freq_table;
>> +       unsigned int *volt_tbl = exynos_volt_table;
>> +       const struct property *prop;
>> +       const __be32 *val;
>> +
>> +       np =  of_find_compatible_node(NULL, NULL, "samsung,exynos5440-cpufreq");
>> +       if (!np)
>> +               return -ENODEV;
>> +
>> +       dvfs_info = kzalloc(sizeof(struct exynos_dvfs_data), GFP_KERNEL);
>> +       if (!dvfs_info) {
>> +               of_node_put(np);
>> +               return -ENOMEM;
>> +       }
>> +
>> +       dvfs_info->base = of_iomap(np, 0);
>> +       if (!dvfs_info->base) {
>> +               pr_err("No cpufreq memory map found\n");
>> +               ret = -ENODEV;
>> +               goto err_map;
>> +
>> +       }
>> +
>> +       dvfs_info->irq = irq_of_parse_and_map(np, 0);
>> +
>> +       if (dvfs_info->irq == 0) {
>> +               pr_err("No cpufreq irq found\n");
>> +               ret = -ENODEV;
>> +               goto err_irq_parse;
>> +       }
>> +
>> +       prop = of_find_property(np, "cpufreq_tbl", NULL);
>> +       if (!prop || !prop->value) {
>> +               pr_err("No cpufreq table found\n");
>> +               ret = -ENODEV;
>> +               goto err_irq_parse;
>> +       }
>> +
>> +       len = prop->length / sizeof(u32);
>> +       val = prop->value;
>> +
>> +       if ((len == 0) || (len / 2 > CPUFREQ_LEVEL_END)) {
>> +               pr_err("Invalid cpufreq table\n");
>> +               ret = -ENODEV;
>> +               goto err_irq_parse;
>> +       }
>> +
>> +       for (i = 0; i < (len / 2); i++) {
>> +               freq_tbl[i].index = i;
>> +               freq_tbl[i].frequency = be32_to_cpup(val++);
>> +               volt_tbl[i] = be32_to_cpup(val++);
>> +       }
>> +
>> +       freq_tbl[i].index = i;
>> +       freq_tbl[i].frequency = CPUFREQ_TABLE_END;
>
> How about using OPP library to allocate and setup freqtable ? It will
> clean up this code and you wont have to have a statically allocated
> exynos_freq_table.

Ok I will check for this.

Thanks,
Amit
>
> Thanks,
> Inder
>
>> +
>> +       dvfs_info->freq_table = freq_tbl;
>> +
>> +       dvfs_info->cpu_clk = clk_get(NULL, "armclk");
>> +       if (IS_ERR(dvfs_info->cpu_clk)) {
>> +               pr_err("Failed to get cpu clock\n");
>> +               ret = PTR_ERR(dvfs_info->cpu_clk);
>> +               goto err_irq_parse;
>> +       }
>> +
>> +       INIT_WORK(&dvfs_info->irq_work, exynos_cpufreq_work);
>> +       if (request_irq(dvfs_info->irq, exynos_cpufreq_irq,
>> +                               IRQF_TRIGGER_NONE, DRIVER_NAME, dvfs_info)) {
>> +               pr_err("Failed to register IRQ\n");
>> +               ret = -ENODEV;
>> +               goto err_irq_req;
>> +       }
>> +
>> +       dvfs_info->cur_frequency = clk_get_rate(dvfs_info->cpu_clk) / 1000;
>> +       init_div_table();
>> +       exynos_enable_dvfs();
>> +
>> +       if (cpufreq_register_driver(&exynos_driver)) {
>> +               pr_err("%s: failed to register cpufreq driver\n", __func__);
>> +               goto err_register;
>> +       }
>> +
>> +       of_node_put(np);
>> +       dvfs_info->dvfs_init = true;
>> +       pr_info("exynos5440 DVFS initialised.\n");
>> +
>> +       return 0;
>> +
>> +err_register:
>> +       free_irq(dvfs_info->irq, dvfs_info);
>> +err_irq_req:
>> +       clk_put(dvfs_info->cpu_clk);
>> +err_irq_parse:
>> +       iounmap(dvfs_info->base);
>> +err_map:
>> +       of_node_put(np);
>> +       kfree(dvfs_info);
>> +       pr_err("%s: failed initialization\n", __func__);
>> +       return -EINVAL;
>> +}
>> +late_initcall(exynos_cpufreq_init);
>> --
>> 1.7.10.4
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> --
> To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
amit kachhap Feb. 7, 2013, 7:08 p.m. UTC | #6
Hi Viresh,

Thanks for the detailed review. Will try to handle them in the next version,

On Thu, Feb 7, 2013 at 3:17 AM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> On Thu, Feb 7, 2013 at 1:09 AM, Amit Daniel Kachhap
> <amit.daniel@samsung.com> wrote:
>> This patch adds dvfs support for exynos5440 SOC. The nature of exynos5440
>> clock controller is different from previous exynos controllers so not using
>> the common exynos cpufreq framework. Also, the device tree parsing is added
>> to get different parameters like frequency, voltage etc.
>
> Some information about platform cpu configuration would be helpful.. cpus, type,
> clock lines for cpus - shared/separate?
Ok.
>
>> Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
>> ---
>>  .../bindings/cpufreq/cpufreq-exynos5440.txt        |   24 ++
>>  drivers/cpufreq/Kconfig.arm                        |    8 +
>>  drivers/cpufreq/Makefile                           |    1 +
>>  drivers/cpufreq/exynos5440-cpufreq.c               |  448 ++++++++++++++++++++
>>  4 files changed, 481 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
>>  create mode 100644 drivers/cpufreq/exynos5440-cpufreq.c
>>
>> diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
>> new file mode 100644
>> index 0000000..96cb0ed
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
>> @@ -0,0 +1,24 @@
>> +
>> +Exynos5440 cpufreq driver
>> +-------------------
>> +
>> +Exynos5440 SoC cpufreq driver for CPU frequency scaling.
>> +
>> +Required properties:
>> +- interrupts: Interrupt to know the completion of cpu frequency change.
>> +- cpufreq_tbl: Table of frequencies and voltage CPU could be transitioned into,
>
> This has to be "operating-points" as in cpufreq-cpu0 driver.
Yes I will check if opp table is beneficial. In my case it is just one
time parsing of cpufreq table and those values(freq, volt) are not
used later so did not use opp libraries.
>
>> +       in the decreasing order. Frequency should be in KHZ units and voltage
>> +       should be in microvolts.
>> +
>> +All the required listed above must be defined under node cpufreq.
>> +
>> +Example:
>> +--------
>> +       cpufreq@160000 {
>> +               compatible = "samsung,exynos5440-cpufreq";
>> +               reg = <0x160000 0x1000>;
>> +               interrupts = <0 57 0>;
>> +               cpufreq_tbl = < 1200000 1025000
>> +                               1000000 975000
>> +                               800000  925000 >;
>> +       };
>
>> diff --git a/drivers/cpufreq/exynos5440-cpufreq.c b/drivers/cpufreq/exynos5440-cpufreq.c
>> new file mode 100644
>> index 0000000..41d39e2
>> --- /dev/null
>> +++ b/drivers/cpufreq/exynos5440-cpufreq.c
>> @@ -0,0 +1,448 @@
>> +/*
>> + * Copyright (c) 2013 Samsung Electronics Co., Ltd.
>> + *             http://www.samsung.com
>> + *
>> + * Amit Daniel Kachhap <amit.daniel@samsung.com>
>> + *
>> + * EXYNOS5440 - CPU frequency scaling support
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> +*/
>> +
>> +#include <linux/clk.h>
>> +#include <linux/cpufreq.h>
>> +#include <linux/err.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/io.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_irq.h>
>> +#include <linux/slab.h>
>> +
>> +/*Register definations*/
>> +#define XMU_DVFS_CTRL          0x0060
>> +#define XMU_PMU_P0_7           0x0064
>> +#define XMU_C0_3_PSTATE        0x0090
>> +#define XMU_P_LIMIT            0x00A0
>> +#define XMU_P_STATUS           0x00A4
>> +#define XMU_PMUEVTEN           0x00D0
>> +#define XMU_PMUIRQEN           0x00D4
>> +#define XMU_PMUIRQ             0x00D8
>> +
>> +/*PMU mask and shift definations*/
>> +#define P_VALUE_MASK           0x7
>> +
>> +#define XMU_DVFS_CTRL_EN_SHIFT 0
>> +
>> +#define P0_7_CPUCLKDEV_SHIFT   21
>> +#define P0_7_CPUCLKDEV_MASK    0x7
>> +#define P0_7_ATBCLKDEV_SHIFT   18
>> +#define P0_7_ATBCLKDEV_MASK    0x7
>> +#define P0_7_CSCLKDEV_SHIFT    15
>> +#define P0_7_CSCLKDEV_MASK     0x7
>> +#define P0_7_CPUEMA_SHIFT      28
>> +#define P0_7_CPUEMA_MASK       0xf
>> +#define P0_7_L2EMA_SHIFT       24
>> +#define P0_7_L2EMA_MASK        0xf
>> +#define P0_7_VDD_SHIFT         8
>> +#define P0_7_VDD_MASK          0x7f
>> +#define P0_7_FREQ_SHIFT                0
>> +#define P0_7_FREQ_MASK         0xff
>> +
>> +#define C0_3_PSTATE_VALID_SHIFT        8
>> +#define C0_3_PSTATE_CURR_SHIFT 4
>> +#define C0_3_PSTATE_NEW_SHIFT  0
>> +
>> +#define PSTATE_CHANGED_EVTEN_SHIFT     0
>> +
>> +#define PSTATE_CHANGED_IRQEN_SHIFT     0
>> +
>> +#define PSTATE_CHANGED_SHIFT           0
>> +
>> +/*some constant values for clock divider calculation*/
>> +#define CPU_DIV_FREQ_MAX       500
>> +#define CPU_DBG_FREQ_MAX       375
>> +#define CPU_ATB_FREQ_MAX       500
>> +
>> +#define PMIC_LOW_VOLT          0x30
>> +#define PMIC_HIGH_VOLT         0x28
>> +
>> +#define CPUEMA_HIGH            0x2
>> +#define CPUEMA_MID             0x4
>> +#define CPUEMA_LOW             0x7
>> +
>> +#define L2EMA_HIGH             0x1
>> +#define L2EMA_MID              0x3
>> +#define L2EMA_LOW              0x4
>> +
>> +#define DIV_TAB_MAX    2
>> +/*frequency unit is 20MHZ*/
>> +#define FREQ_UNIT      20
>> +#define MAX_VOLTAGE    1550000 /*In micro volt*/
>> +#define VOLTAGE_STEP   12500   /*In micro volt*/
>> +
>> +#define DRIVER_NAME            "exynos5440_dvfs"
>> +#define DEF_TRANS_LATENCY      100000
>> +
>> +enum cpufreq_level_index {
>> +       L0, L1, L2, L3, L4,
>> +       L5, L6, L7, L8, L9,
>> +};
>> +#define CPUFREQ_LEVEL_END      (L7 + 1)
>> +
>> +struct exynos_dvfs_data {
>> +       void __iomem *base;
>> +       struct resource *mem;
>> +       int irq;
>> +       struct clk *cpu_clk;
>> +       unsigned int cur_frequency;
>> +       bool dvfs_init;
>> +       struct cpufreq_frequency_table *freq_table;
>> +       struct work_struct irq_work;
>> +};
>> +
>> +static struct exynos_dvfs_data *dvfs_info;
>> +static DEFINE_MUTEX(cpufreq_lock);
>> +static struct cpufreq_freqs freqs;
>> +static struct cpufreq_frequency_table exynos_freq_table[CPUFREQ_LEVEL_END + 1];
>> +static unsigned int exynos_volt_table[CPUFREQ_LEVEL_END + 1];
>> +
>> +static void init_div_table(void)
>> +{
>> +       struct cpufreq_frequency_table *freq_tbl = exynos_freq_table;
>> +       unsigned int *volt_tbl = exynos_volt_table;
>> +       unsigned int tmp, clk_div, ema_div, freq, volt_id;
>> +       int i = 0;
>> +
>> +       for (i = 0; freq_tbl[i].frequency != CPUFREQ_TABLE_END; i++) {
>> +
>> +               freq = freq_tbl[i].frequency / 1000; /*In MHZ*/
>> +               clk_div = ((freq / CPU_DIV_FREQ_MAX) & P0_7_CPUCLKDEV_MASK)
>> +                                       << P0_7_CPUCLKDEV_SHIFT;
>> +               clk_div |= ((freq / CPU_ATB_FREQ_MAX) & P0_7_ATBCLKDEV_MASK)
>> +                                       << P0_7_ATBCLKDEV_SHIFT;
>> +               clk_div |= ((freq / CPU_DBG_FREQ_MAX) & P0_7_CSCLKDEV_MASK)
>> +                                       << P0_7_CSCLKDEV_SHIFT;
>> +
>> +               /*Calculate EMA*/
>> +               volt_id = (MAX_VOLTAGE - volt_tbl[i]) / VOLTAGE_STEP;
>> +               if (volt_id < PMIC_HIGH_VOLT) {
>> +                       ema_div = (CPUEMA_HIGH << P0_7_CPUEMA_SHIFT) |
>> +                               (L2EMA_HIGH << P0_7_L2EMA_SHIFT);
>> +               } else if (volt_id > PMIC_LOW_VOLT) {
>> +                       ema_div = (CPUEMA_LOW << P0_7_CPUEMA_SHIFT) |
>> +                               (L2EMA_LOW << P0_7_L2EMA_SHIFT);
>> +               } else {
>> +                       ema_div = (CPUEMA_MID << P0_7_CPUEMA_SHIFT) |
>> +                               (L2EMA_MID << P0_7_L2EMA_SHIFT);
>> +               }
>> +
>> +               tmp = (clk_div | ema_div | (volt_id << P0_7_VDD_SHIFT)
>> +                       | ((freq / FREQ_UNIT) << P0_7_FREQ_SHIFT));
>> +
>> +               __raw_writel(tmp, dvfs_info->base + XMU_PMU_P0_7 + 4 * i);
>> +       }
>> +}
>> +
>> +void exynos_enable_dvfs(void)
>> +{
>> +       unsigned int tmp, i, cpu;
>> +       struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
>> +       /*Disable DVFS*/
>> +       __raw_writel(0, dvfs_info->base + XMU_DVFS_CTRL);
>> +
>> +       /*Enable PSTATE Change Event*/
>> +       tmp = __raw_readl(dvfs_info->base + XMU_PMUEVTEN);
>> +       tmp |= (1 << PSTATE_CHANGED_EVTEN_SHIFT);
>> +        __raw_writel(tmp, dvfs_info->base + XMU_PMUEVTEN);
>> +
>> +       /*Enable PSTATE Change IRQ*/
>> +       tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQEN);
>> +       tmp |= (1 << PSTATE_CHANGED_IRQEN_SHIFT);
>> +        __raw_writel(tmp, dvfs_info->base + XMU_PMUIRQEN);
>> +
>> +       /*Set initial perfromance index*/
>
> performance.
yes
>
>> +       for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
>> +               if (freq_table[i].frequency == dvfs_info->cur_frequency)
>> +                       break;
>> +
>> +       if (freq_table[i].frequency == CPUFREQ_TABLE_END) {
>> +               pr_crit("Boot up frequency not supported\n");
>> +               if (i) {
>> +                       /*Assign the highest frequency*/
>> +                       i = 0;
>> +                       dvfs_info->cur_frequency = freq_table[i].frequency;
>> +               } else {
>> +                       return;
>> +               }
>> +       }
>> +       pr_info("Setting dvfs initial frequency = %u",
>> +                                               dvfs_info->cur_frequency);
>> +
>> +       for (cpu = 0; cpu < CONFIG_NR_CPUS; cpu++) {
>> +               tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
>> +               tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
>> +               tmp |= (i << C0_3_PSTATE_NEW_SHIFT);
>> +               __raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
>> +       }
>> +
>> +       /*Enable DVFS*/
>> +       __raw_writel(1 << XMU_DVFS_CTRL_EN_SHIFT,
>> +                               dvfs_info->base + XMU_DVFS_CTRL);
>> +}
>> +
>> +static int exynos_verify_speed(struct cpufreq_policy *policy)
>> +{
>> +       return cpufreq_frequency_table_verify(policy,
>> +                                             dvfs_info->freq_table);
>> +}
>> +
>> +static unsigned int exynos_getspeed(unsigned int cpu)
>> +{
>> +       return dvfs_info->cur_frequency;
>> +}
>> +
>> +static int exynos_target(struct cpufreq_policy *policy,
>> +                         unsigned int target_freq,
>> +                         unsigned int relation)
>> +{
>> +       unsigned int index, old_index, tmp;
>> +       int ret = 0, i;
>> +       struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
>> +
>> +       mutex_lock(&cpufreq_lock);
>> +
>> +       freqs.old = dvfs_info->cur_frequency;
>> +
>> +       if (dvfs_info->dvfs_init == false) {
>> +               ret = -EAGAIN;
>> +               goto out;
>> +       }
>> +
>> +       /*
>> +        * The policy max have been changed so that we cannot get proper
>> +        * old_index with cpufreq_frequency_table_target(). Thus, ignore
>> +        * policy and get the index from the raw freqeuncy table.
>> +        */
>
> What? Why ?
Invalid comment, ignore it.
>
>> +       for (old_index = 0;
>> +               freq_table[old_index].frequency != CPUFREQ_TABLE_END;
>> +               old_index++)
>> +               if (freq_table[old_index].frequency == freqs.old)
>> +                       break;
>> +
>> +       if (freq_table[old_index].frequency == CPUFREQ_TABLE_END) {
>
> How can this be true?
This is error scenario
>
>> +               ret = -EINVAL;
>> +               goto out;
>> +       }
>> +
>> +       if (cpufreq_frequency_table_target(policy, freq_table,
>> +                                          target_freq, relation, &index)) {
>> +               ret = -EINVAL;
>> +               goto out;
>> +       }
>> +
>> +       freqs.new = freq_table[index].frequency;
>> +       freqs.cpu = policy->cpu;
>> +
>> +       for_each_cpu(freqs.cpu, policy->cpus)
>> +               cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
>> +
>> +       /*Set the target frequency in all C0_3_PSTATE register*/
>> +       for_each_cpu(i, policy->cpus) {
>> +               tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
>> +               tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
>> +               tmp |= (index << C0_3_PSTATE_NEW_SHIFT);
>> +
>> +               __raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
>> +       }
>> +out:
>> +       mutex_unlock(&cpufreq_lock);
>
> That's something new and interesting. So you are just configuring your
> controller
> for a new dvfs point and get back to work. Then you would get an
> interrupt sometime
> and work is queued and everybody notified.
>
> @Rafael: You expect any issue with this technique ?
>
Yes you understood it correctly. So in this method  prechange and
postchange notifiers are called in a separate context. I guess it
should be fine.
>> +       return ret;
>> +}
>> +
>> +static void exynos_cpufreq_work(struct work_struct *work)
>> +{
>> +       unsigned int cur_pstate, index;
>> +       struct cpufreq_policy *policy = cpufreq_cpu_get(0); /* boot CPU */
>> +       struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
>> +
>> +       mutex_lock(&cpufreq_lock);
>> +
>> +       freqs.old = dvfs_info->cur_frequency;
>> +
>> +       cur_pstate = __raw_readl(dvfs_info->base + XMU_P_STATUS);
>> +       if (cur_pstate >> C0_3_PSTATE_VALID_SHIFT & 0x1)
>> +               index = (cur_pstate >> C0_3_PSTATE_CURR_SHIFT) & P_VALUE_MASK;
>> +       else
>> +               index = (cur_pstate >> C0_3_PSTATE_NEW_SHIFT) & P_VALUE_MASK;
>> +
>> +       if (index < CPUFREQ_LEVEL_END)
>> +               freqs.new = freq_table[index].frequency;
>> +
>> +       for_each_cpu(freqs.cpu, policy->cpus)
>> +               cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
>> +
>> +       dvfs_info->cur_frequency = freqs.new;
>> +
>> +       cpufreq_cpu_put(policy);
>> +       mutex_unlock(&cpufreq_lock);
>> +       enable_irq(dvfs_info->irq);
>> +}
>> +
>> +static irqreturn_t exynos_cpufreq_irq(int irq, void *id)
>> +{
>> +       unsigned int tmp;
>> +
>> +       tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQ);
>> +       if (tmp >> PSTATE_CHANGED_SHIFT & 0x1) {
>> +               __raw_writel(tmp, dvfs_info->base + XMU_PMUIRQ);
>> +
>> +               if (dvfs_info->dvfs_init == true) {
>> +                       disable_irq_nosync(irq);
>> +                       schedule_work(&dvfs_info->irq_work);
>> +               }
>> +       }
>> +       return IRQ_HANDLED;
>> +}
>> +
>> +static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
>> +{
>> +       policy->cur = policy->min = policy->max = dvfs_info->cur_frequency;
>
> you don't have to fill min and max. its done by core when you call
> cpufreq_frequency_table_cpuinfo().
Ok.
>
>> +
>> +       cpufreq_frequency_table_get_attr(dvfs_info->freq_table, policy->cpu);
>> +
>> +       /* set the transition latency value */
>> +       policy->cpuinfo.transition_latency = DEF_TRANS_LATENCY;
>> +
>> +       /*
>> +        * EXYNOS5440 multi-core processors has 4 cores
>> +        * that the frequency cannot be set independently.
>> +        * Each cpu is bound to the same speed.
>> +        * So the affected cpu is all of the cpus.
>> +        */
>
> Good. I understood it now :)
>
>> +       if (num_online_cpus() == 1) {
>> +               cpumask_copy(policy->related_cpus, cpu_possible_mask);
>> +               cpumask_copy(policy->cpus, cpu_online_mask);
>> +       } else {
>> +               policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
>> +               cpumask_setall(policy->cpus);
>> +       }
>
> Replace everything between "Good" and this line with:
>
> cpumask_setall(policy->cpus);
>
> http://www.spinics.net/lists/cpufreq/msg04091.html
Right. good suggestion
>
>> +       return cpufreq_frequency_table_cpuinfo(policy, dvfs_info->freq_table);
>> +}
>> +
>> +static struct cpufreq_driver exynos_driver = {
>> +       .flags          = CPUFREQ_STICKY,
>> +       .verify         = exynos_verify_speed,
>> +       .target         = exynos_target,
>> +       .get            = exynos_getspeed,
>> +       .init           = exynos_cpufreq_cpu_init,
>> +       .name           = DRIVER_NAME,
>> +};
>> +
>> +static int __init exynos_cpufreq_init(void)
>> +{
>> +       int ret = -EINVAL, len, i;
>> +       struct device_node *np;
>> +       struct cpufreq_frequency_table *freq_tbl = exynos_freq_table;
>> +       unsigned int *volt_tbl = exynos_volt_table;
>
> why do we need duplicate names for global variables here? remove exynos_
> from globals and that would be enough (in case you don't want long names).
Ok
>
>> +       const struct property *prop;
>> +       const __be32 *val;
>> +
>> +       np =  of_find_compatible_node(NULL, NULL, "samsung,exynos5440-cpufreq");
>> +       if (!np)
>> +               return -ENODEV;
>> +
>> +       dvfs_info = kzalloc(sizeof(struct exynos_dvfs_data), GFP_KERNEL);
>
> sizeof(*dvfs_info) ?? why don't make it static too, as you have other
> stuff too.. ?
> The better option for single image solution to allocate everything
> dynamically, so that
> unused drivers don't occupy any space.
>
>> +       if (!dvfs_info) {
>> +               of_node_put(np);
>> +               return -ENOMEM;
>> +       }
>> +
>> +       dvfs_info->base = of_iomap(np, 0);
>> +       if (!dvfs_info->base) {
>> +               pr_err("No cpufreq memory map found\n");
>> +               ret = -ENODEV;
>> +               goto err_map;
>> +
>> +       }
>> +
>> +       dvfs_info->irq = irq_of_parse_and_map(np, 0);
>> +
>> +       if (dvfs_info->irq == 0) {
>> +               pr_err("No cpufreq irq found\n");
>> +               ret = -ENODEV;
>> +               goto err_irq_parse;
>> +       }
>> +
>> +       prop = of_find_property(np, "cpufreq_tbl", NULL);
>> +       if (!prop || !prop->value) {
>> +               pr_err("No cpufreq table found\n");
>> +               ret = -ENODEV;
>> +               goto err_irq_parse;
>> +       }
>> +
>> +       len = prop->length / sizeof(u32);
>> +       val = prop->value;
>> +
>> +       if ((len == 0) || (len / 2 > CPUFREQ_LEVEL_END)) {
>
> I really didn't like this limit you have put at the number of dvfs
> points. Better
> would be to use:
>
>         ret = of_init_opp_table(cpu_dev);
>         if (ret) {
>                 pr_err("failed to init OPP table: %d\n", ret);
>                 goto out_put_node;
>         }
>
>         ret = opp_init_cpufreq_table(cpu_dev, &freq_table);
>         if (ret) {
>                 pr_err("failed to init cpufreq table: %d\n", ret);
>                 goto out_put_node;
>         }
>
> as used in cpufreq-cpu0 driver. Also please have a closer look at this driver,
> you may not your driver at all :)
Yes I thought of this but there are some different things needed in
this driver like
*) prechange and postchange out of context call.
*) some controller initialisations after parsing the cpufreq table.
*) no explicit set voltage call
>
>> +               pr_err("Invalid cpufreq table\n");
>> +               ret = -ENODEV;
>> +               goto err_irq_parse;
>> +       }
>> +
>> +       for (i = 0; i < (len / 2); i++) {
>> +               freq_tbl[i].index = i;
>> +               freq_tbl[i].frequency = be32_to_cpup(val++);
>> +               volt_tbl[i] = be32_to_cpup(val++);
>> +       }
>> +
>> +       freq_tbl[i].index = i;
>> +       freq_tbl[i].frequency = CPUFREQ_TABLE_END;
>> +
>> +       dvfs_info->freq_table = freq_tbl;
>> +
>> +       dvfs_info->cpu_clk = clk_get(NULL, "armclk");
>
> devm_clk_get() ?
Ok
>
>> +       if (IS_ERR(dvfs_info->cpu_clk)) {
>> +               pr_err("Failed to get cpu clock\n");
>> +               ret = PTR_ERR(dvfs_info->cpu_clk);
>> +               goto err_irq_parse;
>> +       }
>> +
>> +       INIT_WORK(&dvfs_info->irq_work, exynos_cpufreq_work);
>> +       if (request_irq(dvfs_info->irq, exynos_cpufreq_irq,
>
> devm_ ??
Ok.
>
>> +                               IRQF_TRIGGER_NONE, DRIVER_NAME, dvfs_info)) {
>> +               pr_err("Failed to register IRQ\n");
>> +               ret = -ENODEV;
>> +               goto err_irq_req;
>> +       }
>> +
>> +       dvfs_info->cur_frequency = clk_get_rate(dvfs_info->cpu_clk) / 1000;
>
> what if clk_get_rate fails ? or returns zero.
Ok.
>
>> +       init_div_table();
>> +       exynos_enable_dvfs();
>> +
>> +       if (cpufreq_register_driver(&exynos_driver)) {
>> +               pr_err("%s: failed to register cpufreq driver\n", __func__);
>> +               goto err_register;
>> +       }
>> +
>> +       of_node_put(np);
>> +       dvfs_info->dvfs_init = true;
>
> why do you need this ?
This is added to synchronize the interrupts.

Thanks,
Amit Daniel
>
>> +       pr_info("exynos5440 DVFS initialised.\n");
>> +
>> +       return 0;
>> +
>> +err_register:
>> +       free_irq(dvfs_info->irq, dvfs_info);
>> +err_irq_req:
>> +       clk_put(dvfs_info->cpu_clk);
>> +err_irq_parse:
>> +       iounmap(dvfs_info->base);
>> +err_map:
>> +       of_node_put(np);
>> +       kfree(dvfs_info);
>> +       pr_err("%s: failed initialization\n", __func__);
>> +       return -EINVAL;
>> +}
>> +late_initcall(exynos_cpufreq_init);
>> --
>> 1.7.10.4
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-pm" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> --
> To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Viresh Kumar Feb. 8, 2013, 2:42 a.m. UTC | #7
On 8 February 2013 00:38, amit kachhap <amit.kachhap@gmail.com> wrote:
> Hi Viresh,
>
> Thanks for the detailed review. Will try to handle them in the next version,

np. I haven't seen reply to few questions, you missed them or accept them.

General tip: Leave a blank line before and after your comment, it makes it more
readable. :)

> On Thu, Feb 7, 2013 at 3:17 AM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
>> On Thu, Feb 7, 2013 at 1:09 AM, Amit Daniel Kachhap
>>> +Required properties:
>>> +- interrupts: Interrupt to know the completion of cpu frequency change.
>>> +- cpufreq_tbl: Table of frequencies and voltage CPU could be transitioned into,
>>
>> This has to be "operating-points" as in cpufreq-cpu0 driver.
> Yes I will check if opp table is beneficial. In my case it is just one
> time parsing of cpufreq table and those values(freq, volt) are not
> used later so did not use opp libraries.

Its one time parsing for everybody, nobody do it twice :)

>>> +       for (old_index = 0;
>>> +               freq_table[old_index].frequency != CPUFREQ_TABLE_END;
>>> +               old_index++)
>>> +               if (freq_table[old_index].frequency == freqs.old)
>>> +                       break;
>>> +
>>> +       if (freq_table[old_index].frequency == CPUFREQ_TABLE_END) {
>>
>> How can this be true?
> This is error scenario

We have given cpufreq core a valid table and it has to set frequency from
this table only. How can cpu have any other freq here ? And you have done
something similar in your init() too, where you check if cpu has freq from the
table or not.

>>> +       dvfs_info = kzalloc(sizeof(struct exynos_dvfs_data), GFP_KERNEL);
>>
>> sizeof(*dvfs_info) ?? why don't make it static too, as you have other
>> stuff too.. ?
>> The better option for single image solution to allocate everything
>> dynamically, so that
>> unused drivers don't occupy any space.

?

>>> +       if ((len == 0) || (len / 2 > CPUFREQ_LEVEL_END)) {
>>
>> I really didn't like this limit you have put at the number of dvfs
>> points. Better
>> would be to use:

>>> +       dvfs_info->dvfs_init = true;
>>
>> why do you need this ?
> This is added to synchronize the interrupts.

How? You are setting it once in init() and not touching it afterwards. :)
--
To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
amit kachhap Feb. 8, 2013, 3:26 a.m. UTC | #8
On Thu, Feb 7, 2013 at 6:42 PM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> On 8 February 2013 00:38, amit kachhap <amit.kachhap@gmail.com> wrote:
>> Hi Viresh,
>>
>> Thanks for the detailed review. Will try to handle them in the next version,
>
> np. I haven't seen reply to few questions, you missed them or accept them.

Many of your comments were apt so I agreed to most of them :)

>
> General tip: Leave a blank line before and after your comment, it makes it more
> readable. :)
>
>> On Thu, Feb 7, 2013 at 3:17 AM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
>>> On Thu, Feb 7, 2013 at 1:09 AM, Amit Daniel Kachhap
>>>> +Required properties:
>>>> +- interrupts: Interrupt to know the completion of cpu frequency change.
>>>> +- cpufreq_tbl: Table of frequencies and voltage CPU could be transitioned into,
>>>
>>> This has to be "operating-points" as in cpufreq-cpu0 driver.
>> Yes I will check if opp table is beneficial. In my case it is just one
>> time parsing of cpufreq table and those values(freq, volt) are not
>> used later so did not use opp libraries.
>
> Its one time parsing for everybody, nobody do it twice :)

By every time I mean like using the opp table and getting voltage from
there and then doing set_voltage. For me if I use opp table it is just
once during initializations so i didn't use it.

>
>>>> +       for (old_index = 0;
>>>> +               freq_table[old_index].frequency != CPUFREQ_TABLE_END;
>>>> +               old_index++)
>>>> +               if (freq_table[old_index].frequency == freqs.old)
>>>> +                       break;
>>>> +
>>>> +       if (freq_table[old_index].frequency == CPUFREQ_TABLE_END) {
>>>
>>> How can this be true?
>> This is error scenario
>
> We have given cpufreq core a valid table and it has to set frequency from
> this table only. How can cpu have any other freq here ? And you have done
> something similar in your init() too, where you check if cpu has freq from the
> table or not.

Yes agreed this is repetition.

>
>>>> +       dvfs_info = kzalloc(sizeof(struct exynos_dvfs_data), GFP_KERNEL);
>>>
>>> sizeof(*dvfs_info) ?? why don't make it static too, as you have other
>>> stuff too.. ?
>>> The better option for single image solution to allocate everything
>>> dynamically, so that
>>> unused drivers don't occupy any space.
>
> ?
>
>>>> +       if ((len == 0) || (len / 2 > CPUFREQ_LEVEL_END)) {
>>>
>>> I really didn't like this limit you have put at the number of dvfs
>>> points. Better
>>> would be to use:
>
>>>> +       dvfs_info->dvfs_init = true;
>>>
>>> why do you need this ?
>> This is added to synchronize the interrupts.
>
> How? You are setting it once in init() and not touching it afterwards. :)

Yes but during init also if interrupts starts arriving before complete
initialization so to protect that case it is there. I suppose there
are other ways. Will check them

Thanks,
Amit Daniel
--
To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Viresh Kumar Feb. 8, 2013, 4:23 a.m. UTC | #9
On 8 February 2013 08:56, amit kachhap <amit.kachhap@gmail.com> wrote:
>>>>> +       dvfs_info->dvfs_init = true;
>>>>
>>>> why do you need this ?
>>> This is added to synchronize the interrupts.
>>
>> How? You are setting it once in init() and not touching it afterwards. :)
>
> Yes but during init also if interrupts starts arriving before complete
> initialization so to protect that case it is there. I suppose there
> are other ways. Will check them

Then clear any pending interrupts from init ()
--
To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
new file mode 100644
index 0000000..96cb0ed
--- /dev/null
+++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
@@ -0,0 +1,24 @@ 
+
+Exynos5440 cpufreq driver
+-------------------
+
+Exynos5440 SoC cpufreq driver for CPU frequency scaling.
+
+Required properties:
+- interrupts: Interrupt to know the completion of cpu frequency change.
+- cpufreq_tbl: Table of frequencies and voltage CPU could be transitioned into,
+	in the decreasing order. Frequency should be in KHZ units and voltage
+	should be in microvolts.
+
+All the required listed above must be defined under node cpufreq.
+
+Example:
+--------
+	cpufreq@160000 {
+		compatible = "samsung,exynos5440-cpufreq";
+		reg = <0x160000 0x1000>;
+		interrupts = <0 57 0>;
+		cpufreq_tbl = <	1200000 1025000
+				1000000 975000
+				800000  925000 >;
+	};
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index a0b3661..554756f 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -77,6 +77,14 @@  config ARM_EXYNOS5250_CPUFREQ
 	  This adds the CPUFreq driver for Samsung EXYNOS5250
 	  SoC.
 
+config ARM_EXYNOS5440_CPUFREQ
+	def_bool SOC_EXYNOS5440
+	help
+	  This adds the CPUFreq driver for Samsung EXYNOS5440
+	  SoC. The nature of exynos5440 clock controller is
+	  different than previous exynos controllers so not using
+	  the common exynos framework.
+
 config ARM_SPEAR_CPUFREQ
 	bool "SPEAr CPUFreq support"
 	depends on PLAT_SPEAR
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index fadc4d4..5159ba4 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -50,6 +50,7 @@  obj-$(CONFIG_ARM_EXYNOS_CPUFREQ)	+= exynos-cpufreq.o
 obj-$(CONFIG_ARM_EXYNOS4210_CPUFREQ)	+= exynos4210-cpufreq.o
 obj-$(CONFIG_ARM_EXYNOS4X12_CPUFREQ)	+= exynos4x12-cpufreq.o
 obj-$(CONFIG_ARM_EXYNOS5250_CPUFREQ)	+= exynos5250-cpufreq.o
+obj-$(CONFIG_ARM_EXYNOS5440_CPUFREQ)	+= exynos5440-cpufreq.o
 obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ)     += omap-cpufreq.o
 obj-$(CONFIG_ARM_SPEAR_CPUFREQ)		+= spear-cpufreq.o
 
diff --git a/drivers/cpufreq/exynos5440-cpufreq.c b/drivers/cpufreq/exynos5440-cpufreq.c
new file mode 100644
index 0000000..41d39e2
--- /dev/null
+++ b/drivers/cpufreq/exynos5440-cpufreq.c
@@ -0,0 +1,448 @@ 
+/*
+ * Copyright (c) 2013 Samsung Electronics Co., Ltd.
+ *		http://www.samsung.com
+ *
+ * Amit Daniel Kachhap <amit.daniel@samsung.com>
+ *
+ * EXYNOS5440 - CPU frequency scaling support
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#include <linux/clk.h>
+#include <linux/cpufreq.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/slab.h>
+
+/*Register definations*/
+#define XMU_DVFS_CTRL		0x0060
+#define XMU_PMU_P0_7		0x0064
+#define XMU_C0_3_PSTATE	0x0090
+#define XMU_P_LIMIT		0x00A0
+#define XMU_P_STATUS		0x00A4
+#define XMU_PMUEVTEN		0x00D0
+#define XMU_PMUIRQEN		0x00D4
+#define XMU_PMUIRQ		0x00D8
+
+/*PMU mask and shift definations*/
+#define P_VALUE_MASK		0x7
+
+#define XMU_DVFS_CTRL_EN_SHIFT	0
+
+#define P0_7_CPUCLKDEV_SHIFT	21
+#define P0_7_CPUCLKDEV_MASK	0x7
+#define P0_7_ATBCLKDEV_SHIFT	18
+#define P0_7_ATBCLKDEV_MASK	0x7
+#define P0_7_CSCLKDEV_SHIFT	15
+#define P0_7_CSCLKDEV_MASK	0x7
+#define P0_7_CPUEMA_SHIFT	28
+#define P0_7_CPUEMA_MASK	0xf
+#define P0_7_L2EMA_SHIFT	24
+#define P0_7_L2EMA_MASK	0xf
+#define P0_7_VDD_SHIFT		8
+#define P0_7_VDD_MASK		0x7f
+#define P0_7_FREQ_SHIFT		0
+#define P0_7_FREQ_MASK		0xff
+
+#define C0_3_PSTATE_VALID_SHIFT	8
+#define C0_3_PSTATE_CURR_SHIFT	4
+#define C0_3_PSTATE_NEW_SHIFT	0
+
+#define PSTATE_CHANGED_EVTEN_SHIFT	0
+
+#define PSTATE_CHANGED_IRQEN_SHIFT	0
+
+#define PSTATE_CHANGED_SHIFT		0
+
+/*some constant values for clock divider calculation*/
+#define CPU_DIV_FREQ_MAX	500
+#define CPU_DBG_FREQ_MAX	375
+#define CPU_ATB_FREQ_MAX	500
+
+#define PMIC_LOW_VOLT		0x30
+#define PMIC_HIGH_VOLT		0x28
+
+#define CPUEMA_HIGH		0x2
+#define CPUEMA_MID		0x4
+#define CPUEMA_LOW		0x7
+
+#define L2EMA_HIGH		0x1
+#define L2EMA_MID		0x3
+#define L2EMA_LOW		0x4
+
+#define DIV_TAB_MAX	2
+/*frequency unit is 20MHZ*/
+#define FREQ_UNIT	20
+#define MAX_VOLTAGE	1550000 /*In micro volt*/
+#define VOLTAGE_STEP	12500	/*In micro volt*/
+
+#define DRIVER_NAME		"exynos5440_dvfs"
+#define DEF_TRANS_LATENCY	100000
+
+enum cpufreq_level_index {
+	L0, L1, L2, L3, L4,
+	L5, L6, L7, L8, L9,
+};
+#define CPUFREQ_LEVEL_END	(L7 + 1)
+
+struct exynos_dvfs_data {
+	void __iomem *base;
+	struct resource *mem;
+	int irq;
+	struct clk *cpu_clk;
+	unsigned int cur_frequency;
+	bool dvfs_init;
+	struct cpufreq_frequency_table *freq_table;
+	struct work_struct irq_work;
+};
+
+static struct exynos_dvfs_data *dvfs_info;
+static DEFINE_MUTEX(cpufreq_lock);
+static struct cpufreq_freqs freqs;
+static struct cpufreq_frequency_table exynos_freq_table[CPUFREQ_LEVEL_END + 1];
+static unsigned int exynos_volt_table[CPUFREQ_LEVEL_END + 1];
+
+static void init_div_table(void)
+{
+	struct cpufreq_frequency_table *freq_tbl = exynos_freq_table;
+	unsigned int *volt_tbl = exynos_volt_table;
+	unsigned int tmp, clk_div, ema_div, freq, volt_id;
+	int i = 0;
+
+	for (i = 0; freq_tbl[i].frequency != CPUFREQ_TABLE_END; i++) {
+
+		freq = freq_tbl[i].frequency / 1000; /*In MHZ*/
+		clk_div = ((freq / CPU_DIV_FREQ_MAX) & P0_7_CPUCLKDEV_MASK)
+					<< P0_7_CPUCLKDEV_SHIFT;
+		clk_div |= ((freq / CPU_ATB_FREQ_MAX) & P0_7_ATBCLKDEV_MASK)
+					<< P0_7_ATBCLKDEV_SHIFT;
+		clk_div |= ((freq / CPU_DBG_FREQ_MAX) & P0_7_CSCLKDEV_MASK)
+					<< P0_7_CSCLKDEV_SHIFT;
+
+		/*Calculate EMA*/
+		volt_id = (MAX_VOLTAGE - volt_tbl[i]) / VOLTAGE_STEP;
+		if (volt_id < PMIC_HIGH_VOLT) {
+			ema_div = (CPUEMA_HIGH << P0_7_CPUEMA_SHIFT) |
+				(L2EMA_HIGH << P0_7_L2EMA_SHIFT);
+		} else if (volt_id > PMIC_LOW_VOLT) {
+			ema_div = (CPUEMA_LOW << P0_7_CPUEMA_SHIFT) |
+				(L2EMA_LOW << P0_7_L2EMA_SHIFT);
+		} else {
+			ema_div = (CPUEMA_MID << P0_7_CPUEMA_SHIFT) |
+				(L2EMA_MID << P0_7_L2EMA_SHIFT);
+		}
+
+		tmp = (clk_div | ema_div | (volt_id << P0_7_VDD_SHIFT)
+			| ((freq / FREQ_UNIT) << P0_7_FREQ_SHIFT));
+
+		__raw_writel(tmp, dvfs_info->base + XMU_PMU_P0_7 + 4 * i);
+	}
+}
+
+void exynos_enable_dvfs(void)
+{
+	unsigned int tmp, i, cpu;
+	struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
+	/*Disable DVFS*/
+	__raw_writel(0,	dvfs_info->base + XMU_DVFS_CTRL);
+
+	/*Enable PSTATE Change Event*/
+	tmp = __raw_readl(dvfs_info->base + XMU_PMUEVTEN);
+	tmp |= (1 << PSTATE_CHANGED_EVTEN_SHIFT);
+	 __raw_writel(tmp, dvfs_info->base + XMU_PMUEVTEN);
+
+	/*Enable PSTATE Change IRQ*/
+	tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQEN);
+	tmp |= (1 << PSTATE_CHANGED_IRQEN_SHIFT);
+	 __raw_writel(tmp, dvfs_info->base + XMU_PMUIRQEN);
+
+	/*Set initial perfromance index*/
+	for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
+		if (freq_table[i].frequency == dvfs_info->cur_frequency)
+			break;
+
+	if (freq_table[i].frequency == CPUFREQ_TABLE_END) {
+		pr_crit("Boot up frequency not supported\n");
+		if (i) {
+			/*Assign the highest frequency*/
+			i = 0;
+			dvfs_info->cur_frequency = freq_table[i].frequency;
+		} else {
+			return;
+		}
+	}
+	pr_info("Setting dvfs initial frequency = %u",
+						dvfs_info->cur_frequency);
+
+	for (cpu = 0; cpu < CONFIG_NR_CPUS; cpu++) {
+		tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
+		tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
+		tmp |= (i << C0_3_PSTATE_NEW_SHIFT);
+		__raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
+	}
+
+	/*Enable DVFS*/
+	__raw_writel(1 << XMU_DVFS_CTRL_EN_SHIFT,
+				dvfs_info->base + XMU_DVFS_CTRL);
+}
+
+static int exynos_verify_speed(struct cpufreq_policy *policy)
+{
+	return cpufreq_frequency_table_verify(policy,
+					      dvfs_info->freq_table);
+}
+
+static unsigned int exynos_getspeed(unsigned int cpu)
+{
+	return dvfs_info->cur_frequency;
+}
+
+static int exynos_target(struct cpufreq_policy *policy,
+			  unsigned int target_freq,
+			  unsigned int relation)
+{
+	unsigned int index, old_index, tmp;
+	int ret = 0, i;
+	struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
+
+	mutex_lock(&cpufreq_lock);
+
+	freqs.old = dvfs_info->cur_frequency;
+
+	if (dvfs_info->dvfs_init == false) {
+		ret = -EAGAIN;
+		goto out;
+	}
+
+	/*
+	 * The policy max have been changed so that we cannot get proper
+	 * old_index with cpufreq_frequency_table_target(). Thus, ignore
+	 * policy and get the index from the raw freqeuncy table.
+	 */
+	for (old_index = 0;
+		freq_table[old_index].frequency != CPUFREQ_TABLE_END;
+		old_index++)
+		if (freq_table[old_index].frequency == freqs.old)
+			break;
+
+	if (freq_table[old_index].frequency == CPUFREQ_TABLE_END) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (cpufreq_frequency_table_target(policy, freq_table,
+					   target_freq, relation, &index)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	freqs.new = freq_table[index].frequency;
+	freqs.cpu = policy->cpu;
+
+	for_each_cpu(freqs.cpu, policy->cpus)
+		cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+	/*Set the target frequency in all C0_3_PSTATE register*/
+	for_each_cpu(i, policy->cpus) {
+		tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
+		tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
+		tmp |= (index << C0_3_PSTATE_NEW_SHIFT);
+
+		__raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
+	}
+out:
+	mutex_unlock(&cpufreq_lock);
+	return ret;
+}
+
+static void exynos_cpufreq_work(struct work_struct *work)
+{
+	unsigned int cur_pstate, index;
+	struct cpufreq_policy *policy = cpufreq_cpu_get(0); /* boot CPU */
+	struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
+
+	mutex_lock(&cpufreq_lock);
+
+	freqs.old = dvfs_info->cur_frequency;
+
+	cur_pstate = __raw_readl(dvfs_info->base + XMU_P_STATUS);
+	if (cur_pstate >> C0_3_PSTATE_VALID_SHIFT & 0x1)
+		index = (cur_pstate >> C0_3_PSTATE_CURR_SHIFT) & P_VALUE_MASK;
+	else
+		index = (cur_pstate >> C0_3_PSTATE_NEW_SHIFT) & P_VALUE_MASK;
+
+	if (index < CPUFREQ_LEVEL_END)
+		freqs.new = freq_table[index].frequency;
+
+	for_each_cpu(freqs.cpu, policy->cpus)
+		cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+
+	dvfs_info->cur_frequency = freqs.new;
+
+	cpufreq_cpu_put(policy);
+	mutex_unlock(&cpufreq_lock);
+	enable_irq(dvfs_info->irq);
+}
+
+static irqreturn_t exynos_cpufreq_irq(int irq, void *id)
+{
+	unsigned int tmp;
+
+	tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQ);
+	if (tmp >> PSTATE_CHANGED_SHIFT & 0x1) {
+		__raw_writel(tmp, dvfs_info->base + XMU_PMUIRQ);
+
+		if (dvfs_info->dvfs_init == true) {
+			disable_irq_nosync(irq);
+			schedule_work(&dvfs_info->irq_work);
+		}
+	}
+	return IRQ_HANDLED;
+}
+
+static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
+{
+	policy->cur = policy->min = policy->max = dvfs_info->cur_frequency;
+
+	cpufreq_frequency_table_get_attr(dvfs_info->freq_table, policy->cpu);
+
+	/* set the transition latency value */
+	policy->cpuinfo.transition_latency = DEF_TRANS_LATENCY;
+
+	/*
+	 * EXYNOS5440 multi-core processors has 4 cores
+	 * that the frequency cannot be set independently.
+	 * Each cpu is bound to the same speed.
+	 * So the affected cpu is all of the cpus.
+	 */
+	if (num_online_cpus() == 1) {
+		cpumask_copy(policy->related_cpus, cpu_possible_mask);
+		cpumask_copy(policy->cpus, cpu_online_mask);
+	} else {
+		policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
+		cpumask_setall(policy->cpus);
+	}
+
+	return cpufreq_frequency_table_cpuinfo(policy, dvfs_info->freq_table);
+}
+
+static struct cpufreq_driver exynos_driver = {
+	.flags		= CPUFREQ_STICKY,
+	.verify		= exynos_verify_speed,
+	.target		= exynos_target,
+	.get		= exynos_getspeed,
+	.init		= exynos_cpufreq_cpu_init,
+	.name		= DRIVER_NAME,
+};
+
+static int __init exynos_cpufreq_init(void)
+{
+	int ret = -EINVAL, len, i;
+	struct device_node *np;
+	struct cpufreq_frequency_table *freq_tbl = exynos_freq_table;
+	unsigned int *volt_tbl = exynos_volt_table;
+	const struct property *prop;
+	const __be32 *val;
+
+	np =  of_find_compatible_node(NULL, NULL, "samsung,exynos5440-cpufreq");
+	if (!np)
+		return -ENODEV;
+
+	dvfs_info = kzalloc(sizeof(struct exynos_dvfs_data), GFP_KERNEL);
+	if (!dvfs_info) {
+		of_node_put(np);
+		return -ENOMEM;
+	}
+
+	dvfs_info->base = of_iomap(np, 0);
+	if (!dvfs_info->base) {
+		pr_err("No cpufreq memory map found\n");
+		ret = -ENODEV;
+		goto err_map;
+
+	}
+
+	dvfs_info->irq = irq_of_parse_and_map(np, 0);
+
+	if (dvfs_info->irq == 0) {
+		pr_err("No cpufreq irq found\n");
+		ret = -ENODEV;
+		goto err_irq_parse;
+	}
+
+	prop = of_find_property(np, "cpufreq_tbl", NULL);
+	if (!prop || !prop->value) {
+		pr_err("No cpufreq table found\n");
+		ret = -ENODEV;
+		goto err_irq_parse;
+	}
+
+	len = prop->length / sizeof(u32);
+	val = prop->value;
+
+	if ((len == 0) || (len / 2 > CPUFREQ_LEVEL_END)) {
+		pr_err("Invalid cpufreq table\n");
+		ret = -ENODEV;
+		goto err_irq_parse;
+	}
+
+	for (i = 0; i < (len / 2); i++) {
+		freq_tbl[i].index = i;
+		freq_tbl[i].frequency = be32_to_cpup(val++);
+		volt_tbl[i] = be32_to_cpup(val++);
+	}
+
+	freq_tbl[i].index = i;
+	freq_tbl[i].frequency = CPUFREQ_TABLE_END;
+
+	dvfs_info->freq_table = freq_tbl;
+
+	dvfs_info->cpu_clk = clk_get(NULL, "armclk");
+	if (IS_ERR(dvfs_info->cpu_clk)) {
+		pr_err("Failed to get cpu clock\n");
+		ret = PTR_ERR(dvfs_info->cpu_clk);
+		goto err_irq_parse;
+	}
+
+	INIT_WORK(&dvfs_info->irq_work, exynos_cpufreq_work);
+	if (request_irq(dvfs_info->irq, exynos_cpufreq_irq,
+				IRQF_TRIGGER_NONE, DRIVER_NAME, dvfs_info)) {
+		pr_err("Failed to register IRQ\n");
+		ret = -ENODEV;
+		goto err_irq_req;
+	}
+
+	dvfs_info->cur_frequency = clk_get_rate(dvfs_info->cpu_clk) / 1000;
+	init_div_table();
+	exynos_enable_dvfs();
+
+	if (cpufreq_register_driver(&exynos_driver)) {
+		pr_err("%s: failed to register cpufreq driver\n", __func__);
+		goto err_register;
+	}
+
+	of_node_put(np);
+	dvfs_info->dvfs_init = true;
+	pr_info("exynos5440 DVFS initialised.\n");
+
+	return 0;
+
+err_register:
+	free_irq(dvfs_info->irq, dvfs_info);
+err_irq_req:
+	clk_put(dvfs_info->cpu_clk);
+err_irq_parse:
+	iounmap(dvfs_info->base);
+err_map:
+	of_node_put(np);
+	kfree(dvfs_info);
+	pr_err("%s: failed initialization\n", __func__);
+	return -EINVAL;
+}
+late_initcall(exynos_cpufreq_init);