[V2,1/4] cpufreq: exynos: Adding cpufreq driver for exynos5440
diff mbox

Message ID 1362216854-6633-1-git-send-email-amit.daniel@samsung.com
State New, archived
Headers show

Commit Message

Amit Kachhap March 2, 2013, 9:34 a.m. UTC
This patch adds dvfs support for exynos5440 SOC. This soc has 4 cores and
they run at same frequency. The nature of exynos5440 clock controller is
different from previous exynos controllers so not using the common exynos
cpufreq framework. The major difference being interrupt notfication for
frequency change. Also, OPP library is used for device tree parsing to get
different parameters like frequency, voltage etc. Since the opp library sorts
the frequency table in ascending order so they are again re-arranged in
descending order. This will have one-to-one mapping with the clock controller
state management logic.

Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
---
Changes in V2:
* Added OPP library support to parse DT parameters.
* Removed a hack to handle interrupts in bootup.
* Added many review comments from Viresh and Inder.

All these patches are dependent on Thomas Abraham common clock patches.
http://www.mail-archive.com/linux-samsung-soc@vger.kernel.org/msg15860.html
 
 .../bindings/cpufreq/cpufreq-exynos5440.txt        |   32 ++
 drivers/cpufreq/Kconfig.arm                        |    9 +
 drivers/cpufreq/Makefile                           |    1 +
 drivers/cpufreq/exynos5440-cpufreq.c               |  450 ++++++++++++++++++++
 4 files changed, 492 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
 create mode 100644 drivers/cpufreq/exynos5440-cpufreq.c

Comments

Viresh Kumar March 5, 2013, 1:18 a.m. UTC | #1
On 2 March 2013 15:04, Amit Daniel Kachhap <amit.daniel@samsung.com> wrote:
> This patch adds dvfs support for exynos5440 SOC. This soc has 4 cores and
> they run at same frequency. The nature of exynos5440 clock controller is
> different from previous exynos controllers so not using the common exynos
> cpufreq framework. The major difference being interrupt notfication for
> frequency change. Also, OPP library is used for device tree parsing to get
> different parameters like frequency, voltage etc. Since the opp library sorts
> the frequency table in ascending order so they are again re-arranged in
> descending order. This will have one-to-one mapping with the clock controller
> state management logic.
>
> Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
> ---
> Changes in V2:
> * Added OPP library support to parse DT parameters.
> * Removed a hack to handle interrupts in bootup.
> * Added many review comments from Viresh and Inder.

Added? Thanks :)

>
> All these patches are dependent on Thomas Abraham common clock patches.
> http://www.mail-archive.com/linux-samsung-soc@vger.kernel.org/msg15860.html
>
>  .../bindings/cpufreq/cpufreq-exynos5440.txt        |   32 ++
>  drivers/cpufreq/Kconfig.arm                        |    9 +
>  drivers/cpufreq/Makefile                           |    1 +
>  drivers/cpufreq/exynos5440-cpufreq.c               |  450 ++++++++++++++++++++
>  4 files changed, 492 insertions(+), 0 deletions(-)
>  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..caa3f8d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
> @@ -0,0 +1,32 @@
> +
> +Exynos5440 cpufreq driver
> +-------------------
> +
> +Exynos5440 SoC cpufreq driver for CPU frequency scaling.
> +
> +Required properties:
> +- interrupts: Interrupt to know the completion of cpu frequency change.
> +- operating-points: 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.
> +- clocks: phandle of the clock from common clock binding. More description can
> +       be found in Documentation/devicetree/bindings/clock/clock-bindings.txt.
> +
> +Optional properties:
> +- clock-latency: Clock transition latency in microsecond.
> +
> +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>;
> +               operating-points = <
> +                               1000000 975000
> +                               800000  925000>;
> +               clocks = <&clock 2>;
> +               clock-latency = <100000>;
> +       };
> +
> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> index 030ddf6..7ed9c4a 100644
> --- a/drivers/cpufreq/Kconfig.arm
> +++ b/drivers/cpufreq/Kconfig.arm
> @@ -77,6 +77,15 @@ config ARM_EXYNOS5250_CPUFREQ
>           This adds the CPUFreq driver for Samsung EXYNOS5250
>           SoC.
>
> +config ARM_EXYNOS5440_CPUFREQ
> +       def_bool SOC_EXYNOS5440
> +       depends on HAVE_CLK && PM_OPP && OF
> +       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_KIRKWOOD_CPUFREQ
>         def_bool ARCH_KIRKWOOD && OF
>         help
> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
> index 863fd18..c841438 100644
> --- a/drivers/cpufreq/Makefile
> +++ b/drivers/cpufreq/Makefile
> @@ -52,6 +52,7 @@ 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_KIRKWOOD_CPUFREQ)     += kirkwood-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..2dc43b1
> --- /dev/null
> +++ b/drivers/cpufreq/exynos5440-cpufreq.c
> @@ -0,0 +1,450 @@
> +/*
> + * 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.
> +*/

Add following here to get better prints from the driver:

#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt

> +
> +#include <linux/clk.h>
> +#include <linux/cpu.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>

Probably include of.h instead of above two?

> +#include <linux/opp.h>
> +#include <linux/slab.h>
> +

> +struct exynos_dvfs_data {
> +       void __iomem *base;
> +       struct resource *mem;
> +       int irq;
> +       struct clk *cpu_clk;
> +       unsigned int cur_frequency;
> +       unsigned int latency;
> +       struct cpufreq_frequency_table *freq_table;
> +       unsigned int freq_count;
> +       struct device *dev;
> +       struct work_struct irq_work;
> +};
> +
> +static struct exynos_dvfs_data *dvfs_info;
> +static DEFINE_MUTEX(cpufreq_lock);
> +static struct cpufreq_freqs freqs;
> +
> +static int init_div_table(void)
> +{
> +       struct cpufreq_frequency_table *freq_tbl = dvfs_info->freq_table;
> +       unsigned int tmp, clk_div, ema_div, freq, volt_id;
> +       int i = 0;
> +       struct opp *opp;
> +
> +       for (i = 0; freq_tbl[i].frequency != CPUFREQ_TABLE_END; i++) {
> +
> +               opp = opp_find_freq_exact(dvfs_info->dev,
> +                                       freq_tbl[i].frequency * 1000, true);
> +               if (IS_ERR(opp)) {
> +                       pr_err("failed to find valid OPP for %u KHZ\n",
> +                                       freq_tbl[i].frequency);
> +                       return PTR_ERR(opp);
> +               }
> +
> +               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 = opp_get_voltage(opp);
> +               volt_id = (MAX_VOLTAGE - volt_id) / 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);
> +       }
> +
> +       return 0;
> +}
> +
> +void exynos_enable_dvfs(void)
> +{
> +       unsigned int tmp, i, cpu;
> +       struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
> +       /*Disable DVFS*/

Please give space after /* and before */ all over your driver.

> +       __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 performance 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");
> +               /*Assign the highest frequency*/
> +               i = 0;
> +               dvfs_info->cur_frequency = freq_table[i].frequency;
> +       }
> +
> +       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, 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 (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;
> +
> +       if (policy == NULL)
> +               goto skip_work;

How can that be true? And if it can be, you will miss POSTCHANGE notifications
too.

> +       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 < dvfs_info->freq_count) {

What if index is greater than count? That's a problem, isn't it?

> +               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);
> +skip_work:
> +       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);
> +               disable_irq_nosync(irq);
> +               schedule_work(&dvfs_info->irq_work);
> +       }
> +       return IRQ_HANDLED;
> +}
> +
> +static void exynos_sort_descend_freq_table(void)
> +{
> +       struct cpufreq_frequency_table *freq_tbl = dvfs_info->freq_table;
> +       int i = 0, index;
> +       unsigned int tmp_freq;
> +
> +       /*
> +        *Freq table is already in ascending order as it is created from

You need space after * here too :)

> +        *OPP library, so just swap the elements to make it descending.
> +        */
> +       for (i = 0; i < dvfs_info->freq_count / 2; i++) {
> +               index = dvfs_info->freq_count - i - 1;
> +               tmp_freq = freq_tbl[i].frequency;
> +               freq_tbl[i].frequency = freq_tbl[index].frequency;
> +               freq_tbl[index].frequency = tmp_freq;
> +       }
> +}
> +
> +static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
> +{
> +
> +       policy->cur = dvfs_info->cur_frequency;
> +       cpufreq_frequency_table_get_attr(dvfs_info->freq_table, policy->cpu);
> +
> +       /* set the transition latency value */
> +       policy->cpuinfo.transition_latency = dvfs_info->latency;
> +
> +       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)

probably calling it probe might make more sense?

> +{
> +       int ret = -EINVAL;
> +       struct device_node *np;
> +
> +       np =  of_find_compatible_node(NULL, NULL, "samsung,exynos5440-cpufreq");
> +       if (IS_ERR(np))

!np ??

> +               return -ENODEV;
> +
> +       dvfs_info = kzalloc(sizeof(struct exynos_dvfs_data), GFP_KERNEL);

sizeof(*dvfs_info) ??

> +       if (IS_ERR(dvfs_info)) {

IS_ERR_OR_NULL? But i believe kzalloc only returns NULL to show error, so
you may end up using if(!dvfs_info)

> +               ret = -ENOMEM;
> +               goto err_mem_data;
> +       }
> +
> +       dvfs_info->base = of_iomap(np, 0);
> +       if (IS_ERR(dvfs_info->base)) {

same here too..

> +               pr_err("No cpufreq memory map found\n");
> +               ret = -ENODEV;
> +               goto err_map;
> +       }
> +
> +       dvfs_info->irq = irq_of_parse_and_map(np, 0);
> +

can remove blank line.

> +       if (dvfs_info->irq == 0) {
> +               pr_err("No cpufreq irq found\n");
> +               ret = -ENODEV;
> +               goto err_irq_parse;
> +       }
> +
> +       dvfs_info->dev = get_cpu_device(0);

What about using this dev instance to call devm_*** routines everywhere in init.

> +       if (IS_ERR(dvfs_info->dev)) {
> +               pr_err("failed to get cpu0 device\n");
> +               ret = -ENODEV;
> +               goto err_irq_parse;
> +       }
> +
> +       dvfs_info->dev->of_node = np;

So you are setting cpufreq node as node of cpu, I don't know if this is a
good idea. In that case it would be better to create the cpu node instead
and put the table into it.

> +       ret = of_init_opp_table(dvfs_info->dev);
> +       if (ret) {
> +               pr_err("failed to init OPP table: %d\n", ret);
> +               goto err_irq_parse;
> +       }
> +
> +       ret = opp_init_cpufreq_table(dvfs_info->dev, &dvfs_info->freq_table);
> +       if (ret) {
> +               pr_err("failed to init cpufreq table: %d\n", ret);
> +               goto err_irq_parse;
> +       }
> +       dvfs_info->freq_count = opp_get_opp_count(dvfs_info->dev);
> +       exynos_sort_descend_freq_table();
> +
> +       if (of_property_read_u32(np, "clock-latency", &dvfs_info->latency))
> +               dvfs_info->latency = DEF_TRANS_LATENCY;
> +
> +       dvfs_info->cpu_clk = of_clk_get(np, 0);
> +       if (IS_ERR(dvfs_info->cpu_clk)) {
> +               pr_err("Failed to get cpu clock\n");
> +               ret = PTR_ERR(dvfs_info->cpu_clk);
> +               goto err_clk_get;
> +       }
> +
> +       dvfs_info->cur_frequency = clk_get_rate(dvfs_info->cpu_clk);
> +       if (!dvfs_info->cur_frequency) {
> +               pr_err("Failed to get clock rate\n");
> +               ret = -EINVAL;
> +               goto err_clk_get_rate;
> +       }
> +       dvfs_info->cur_frequency /= 1000;
> +
> +       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_clk_get_rate;
> +       }
> +
> +       ret = init_div_table();
> +       if (ret) {
> +               pr_err("Failed to initialise div table\n");

s/initialise/initialize

> +               goto err_div_table;
> +       }
> +
> +       exynos_enable_dvfs();
> +       ret = cpufreq_register_driver(&exynos_driver);
> +       if (ret) {
> +               pr_err("%s: failed to register cpufreq driver\n", __func__);
> +               goto err_div_table;
> +       }
> +
> +       of_node_put(np);
> +
> +       pr_info("exynos5440 DVFS initialised.\n");
> +
> +       return 0;
> +
> +err_div_table:
> +       free_irq(dvfs_info->irq, dvfs_info);
> +err_clk_get_rate:
> +       clk_put(dvfs_info->cpu_clk);
> +err_clk_get:
> +       opp_free_cpufreq_table(dvfs_info->dev, &dvfs_info->freq_table);
> +err_irq_parse:
> +       iounmap(dvfs_info->base);
> +err_map:
> +       kfree(dvfs_info);
> +err_mem_data:
> +       of_node_put(np);
> +       pr_err("%s: failed initialization\n", __func__);
> +       return ret;
> +}
> +late_initcall(exynos_cpufreq_init);
> --
> 1.7.1
>
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amit kachhap March 6, 2013, 5:35 a.m. UTC | #2
Hi Viresh,

Again thanks for your review comments.

On Tue, Mar 5, 2013 at 6:48 AM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> On 2 March 2013 15:04, Amit Daniel Kachhap <amit.daniel@samsung.com> wrote:
>> This patch adds dvfs support for exynos5440 SOC. This soc has 4 cores and
>> they run at same frequency. The nature of exynos5440 clock controller is
>> different from previous exynos controllers so not using the common exynos
>> cpufreq framework. The major difference being interrupt notfication for
>> frequency change. Also, OPP library is used for device tree parsing to get
>> different parameters like frequency, voltage etc. Since the opp library sorts
>> the frequency table in ascending order so they are again re-arranged in
>> descending order. This will have one-to-one mapping with the clock controller
>> state management logic.
>>
>> Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
>> ---
>> Changes in V2:
>> * Added OPP library support to parse DT parameters.
>> * Removed a hack to handle interrupts in bootup.
>> * Added many review comments from Viresh and Inder.
>
> Added? Thanks :)
typo error :)

>
>>
>> All these patches are dependent on Thomas Abraham common clock patches.
>> http://www.mail-archive.com/linux-samsung-soc@vger.kernel.org/msg15860.html
>>
>>  .../bindings/cpufreq/cpufreq-exynos5440.txt        |   32 ++
>>  drivers/cpufreq/Kconfig.arm                        |    9 +
>>  drivers/cpufreq/Makefile                           |    1 +
>>  drivers/cpufreq/exynos5440-cpufreq.c               |  450 ++++++++++++++++++++
>>  4 files changed, 492 insertions(+), 0 deletions(-)
>>  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..caa3f8d
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
>> @@ -0,0 +1,32 @@
>> +
>> +Exynos5440 cpufreq driver
>> +-------------------
>> +
>> +Exynos5440 SoC cpufreq driver for CPU frequency scaling.
>> +
>> +Required properties:
>> +- interrupts: Interrupt to know the completion of cpu frequency change.
>> +- operating-points: 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.
>> +- clocks: phandle of the clock from common clock binding. More description can
>> +       be found in Documentation/devicetree/bindings/clock/clock-bindings.txt.
>> +
>> +Optional properties:
>> +- clock-latency: Clock transition latency in microsecond.
>> +
>> +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>;
>> +               operating-points = <
>> +                               1000000 975000
>> +                               800000  925000>;
>> +               clocks = <&clock 2>;
>> +               clock-latency = <100000>;
>> +       };
>> +
>> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
>> index 030ddf6..7ed9c4a 100644
>> --- a/drivers/cpufreq/Kconfig.arm
>> +++ b/drivers/cpufreq/Kconfig.arm
>> @@ -77,6 +77,15 @@ config ARM_EXYNOS5250_CPUFREQ
>>           This adds the CPUFreq driver for Samsung EXYNOS5250
>>           SoC.
>>
>> +config ARM_EXYNOS5440_CPUFREQ
>> +       def_bool SOC_EXYNOS5440
>> +       depends on HAVE_CLK && PM_OPP && OF
>> +       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_KIRKWOOD_CPUFREQ
>>         def_bool ARCH_KIRKWOOD && OF
>>         help
>> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
>> index 863fd18..c841438 100644
>> --- a/drivers/cpufreq/Makefile
>> +++ b/drivers/cpufreq/Makefile
>> @@ -52,6 +52,7 @@ 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_KIRKWOOD_CPUFREQ)     += kirkwood-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..2dc43b1
>> --- /dev/null
>> +++ b/drivers/cpufreq/exynos5440-cpufreq.c
>> @@ -0,0 +1,450 @@
>> +/*
>> + * 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.
>> +*/
>
> Add following here to get better prints from the driver:
>
> #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
ok will add.
>
>> +
>> +#include <linux/clk.h>
>> +#include <linux/cpu.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>
>
> Probably include of.h instead of above two?
No both are needed . actually these two .h are superset of of.h
>
>> +#include <linux/opp.h>
>> +#include <linux/slab.h>
>> +
>
>> +struct exynos_dvfs_data {
>> +       void __iomem *base;
>> +       struct resource *mem;
>> +       int irq;
>> +       struct clk *cpu_clk;
>> +       unsigned int cur_frequency;
>> +       unsigned int latency;
>> +       struct cpufreq_frequency_table *freq_table;
>> +       unsigned int freq_count;
>> +       struct device *dev;
>> +       struct work_struct irq_work;
>> +};
>> +
>> +static struct exynos_dvfs_data *dvfs_info;
>> +static DEFINE_MUTEX(cpufreq_lock);
>> +static struct cpufreq_freqs freqs;
>> +
>> +static int init_div_table(void)
>> +{
>> +       struct cpufreq_frequency_table *freq_tbl = dvfs_info->freq_table;
>> +       unsigned int tmp, clk_div, ema_div, freq, volt_id;
>> +       int i = 0;
>> +       struct opp *opp;
>> +
>> +       for (i = 0; freq_tbl[i].frequency != CPUFREQ_TABLE_END; i++) {
>> +
>> +               opp = opp_find_freq_exact(dvfs_info->dev,
>> +                                       freq_tbl[i].frequency * 1000, true);
>> +               if (IS_ERR(opp)) {
>> +                       pr_err("failed to find valid OPP for %u KHZ\n",
>> +                                       freq_tbl[i].frequency);
>> +                       return PTR_ERR(opp);
>> +               }
>> +
>> +               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 = opp_get_voltage(opp);
>> +               volt_id = (MAX_VOLTAGE - volt_id) / 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);
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +void exynos_enable_dvfs(void)
>> +{
>> +       unsigned int tmp, i, cpu;
>> +       struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
>> +       /*Disable DVFS*/
>
> Please give space after /* and before */ all over your driver.
ok.
>
>> +       __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 performance 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");
>> +               /*Assign the highest frequency*/
>> +               i = 0;
>> +               dvfs_info->cur_frequency = freq_table[i].frequency;
>> +       }
>> +
>> +       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, 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 (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;
>> +
>> +       if (policy == NULL)
>> +               goto skip_work;
>
> How can that be true? And if it can be, you will miss POSTCHANGE notifications
> too.
This skip of POSTCHANGE notifications is needed in one case where
bootup frequency does not match with any elements of cpufreq table and
hence I simply assign the highest frequency. Also cpufreq driver is
not registered at this point.
>
>> +       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 < dvfs_info->freq_count) {
>
> What if index is greater than count? That's a problem, isn't it?
yes will check this.
>
>> +               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);
>> +skip_work:
>> +       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);
>> +               disable_irq_nosync(irq);
>> +               schedule_work(&dvfs_info->irq_work);
>> +       }
>> +       return IRQ_HANDLED;
>> +}
>> +
>> +static void exynos_sort_descend_freq_table(void)
>> +{
>> +       struct cpufreq_frequency_table *freq_tbl = dvfs_info->freq_table;
>> +       int i = 0, index;
>> +       unsigned int tmp_freq;
>> +
>> +       /*
>> +        *Freq table is already in ascending order as it is created from
>
> You need space after * here too :)
ok.
>
>> +        *OPP library, so just swap the elements to make it descending.
>> +        */
>> +       for (i = 0; i < dvfs_info->freq_count / 2; i++) {
>> +               index = dvfs_info->freq_count - i - 1;
>> +               tmp_freq = freq_tbl[i].frequency;
>> +               freq_tbl[i].frequency = freq_tbl[index].frequency;
>> +               freq_tbl[index].frequency = tmp_freq;
>> +       }
>> +}
>> +
>> +static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
>> +{
>> +
>> +       policy->cur = dvfs_info->cur_frequency;
>> +       cpufreq_frequency_table_get_attr(dvfs_info->freq_table, policy->cpu);
>> +
>> +       /* set the transition latency value */
>> +       policy->cpuinfo.transition_latency = dvfs_info->latency;
>> +
>> +       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)
>
> probably calling it probe might make more sense?
Yes I just checked the recent changes in cpu0-cpufreq driver. probe
makes more sense.
>
>> +{
>> +       int ret = -EINVAL;
>> +       struct device_node *np;
>> +
>> +       np =  of_find_compatible_node(NULL, NULL, "samsung,exynos5440-cpufreq");
>> +       if (IS_ERR(np))
>
> !np ??
ok.
>
>> +               return -ENODEV;
>> +
>> +       dvfs_info = kzalloc(sizeof(struct exynos_dvfs_data), GFP_KERNEL);
>
> sizeof(*dvfs_info) ??
Isn't both same?
>
>> +       if (IS_ERR(dvfs_info)) {
>
> IS_ERR_OR_NULL? But i believe kzalloc only returns NULL to show error, so
> you may end up using if(!dvfs_info)
yes right.
>
>> +               ret = -ENOMEM;
>> +               goto err_mem_data;
>> +       }
>> +
>> +       dvfs_info->base = of_iomap(np, 0);
>> +       if (IS_ERR(dvfs_info->base)) {
>
> same here too..
ok
>
>> +               pr_err("No cpufreq memory map found\n");
>> +               ret = -ENODEV;
>> +               goto err_map;
>> +       }
>> +
>> +       dvfs_info->irq = irq_of_parse_and_map(np, 0);
>> +
>
> can remove blank line.
>
>> +       if (dvfs_info->irq == 0) {
>> +               pr_err("No cpufreq irq found\n");
>> +               ret = -ENODEV;
>> +               goto err_irq_parse;
>> +       }
>> +
>> +       dvfs_info->dev = get_cpu_device(0);
>
> What about using this dev instance to call devm_*** routines everywhere in init.
ok, with probe changes all devm_ api's can be used.
>
>> +       if (IS_ERR(dvfs_info->dev)) {
>> +               pr_err("failed to get cpu0 device\n");
>> +               ret = -ENODEV;
>> +               goto err_irq_parse;
>> +       }
>> +
>> +       dvfs_info->dev->of_node = np;
>
> So you are setting cpufreq node as node of cpu, I don't know if this is a
> good idea. In that case it would be better to create the cpu node instead
> and put the table into it.
yes right.
>
>> +       ret = of_init_opp_table(dvfs_info->dev);
>> +       if (ret) {
>> +               pr_err("failed to init OPP table: %d\n", ret);
>> +               goto err_irq_parse;
>> +       }
>> +
>> +       ret = opp_init_cpufreq_table(dvfs_info->dev, &dvfs_info->freq_table);
>> +       if (ret) {
>> +               pr_err("failed to init cpufreq table: %d\n", ret);
>> +               goto err_irq_parse;
>> +       }
>> +       dvfs_info->freq_count = opp_get_opp_count(dvfs_info->dev);
>> +       exynos_sort_descend_freq_table();
>> +
>> +       if (of_property_read_u32(np, "clock-latency", &dvfs_info->latency))
>> +               dvfs_info->latency = DEF_TRANS_LATENCY;
>> +
>> +       dvfs_info->cpu_clk = of_clk_get(np, 0);
>> +       if (IS_ERR(dvfs_info->cpu_clk)) {
>> +               pr_err("Failed to get cpu clock\n");
>> +               ret = PTR_ERR(dvfs_info->cpu_clk);
>> +               goto err_clk_get;
>> +       }
>> +
>> +       dvfs_info->cur_frequency = clk_get_rate(dvfs_info->cpu_clk);
>> +       if (!dvfs_info->cur_frequency) {
>> +               pr_err("Failed to get clock rate\n");
>> +               ret = -EINVAL;
>> +               goto err_clk_get_rate;
>> +       }
>> +       dvfs_info->cur_frequency /= 1000;
>> +
>> +       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_clk_get_rate;
>> +       }
>> +
>> +       ret = init_div_table();
>> +       if (ret) {
>> +               pr_err("Failed to initialise div table\n");
>
> s/initialise/initialize
ok.

Thanks,
Amit D
>
>> +               goto err_div_table;
>> +       }
>> +
>> +       exynos_enable_dvfs();
>> +       ret = cpufreq_register_driver(&exynos_driver);
>> +       if (ret) {
>> +               pr_err("%s: failed to register cpufreq driver\n", __func__);
>> +               goto err_div_table;
>> +       }
>> +
>> +       of_node_put(np);
>> +
>> +       pr_info("exynos5440 DVFS initialised.\n");
>> +
>> +       return 0;
>> +
>> +err_div_table:
>> +       free_irq(dvfs_info->irq, dvfs_info);
>> +err_clk_get_rate:
>> +       clk_put(dvfs_info->cpu_clk);
>> +err_clk_get:
>> +       opp_free_cpufreq_table(dvfs_info->dev, &dvfs_info->freq_table);
>> +err_irq_parse:
>> +       iounmap(dvfs_info->base);
>> +err_map:
>> +       kfree(dvfs_info);
>> +err_mem_data:
>> +       of_node_put(np);
>> +       pr_err("%s: failed initialization\n", __func__);
>> +       return ret;
>> +}
>> +late_initcall(exynos_cpufreq_init);
>> --
>> 1.7.1
>>
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Viresh Kumar March 6, 2013, 6:21 a.m. UTC | #3
On 6 March 2013 13:35, amit kachhap <amit.kachhap@gmail.com> wrote:
> On Tue, Mar 5, 2013 at 6:48 AM, Viresh Kumar <viresh.kumar@linaro.org> wrote:

>>> +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;
>>> +
>>> +       if (policy == NULL)
>>> +               goto skip_work;
>>
>> How can that be true? And if it can be, you will miss POSTCHANGE notifications
>> too.
> This skip of POSTCHANGE notifications is needed in one case where
> bootup frequency does not match with any elements of cpufreq table and
> hence I simply assign the highest frequency. Also cpufreq driver is
> not registered at this point.

I will keep a variable for that then, otherwise its misleading... So keep a
variable like cpufreq_enabled for it and set it to 1 as soon as this first
interrupt is gone... keep it in unlikely() too.

>>> +       dvfs_info = kzalloc(sizeof(struct exynos_dvfs_data), GFP_KERNEL);
>>
>> sizeof(*dvfs_info) ??
> Isn't both same?

You need to read Documentation/CodingStyle.
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Patch
diff mbox

diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
new file mode 100644
index 0000000..caa3f8d
--- /dev/null
+++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt
@@ -0,0 +1,32 @@ 
+
+Exynos5440 cpufreq driver
+-------------------
+
+Exynos5440 SoC cpufreq driver for CPU frequency scaling.
+
+Required properties:
+- interrupts: Interrupt to know the completion of cpu frequency change.
+- operating-points: 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.
+- clocks: phandle of the clock from common clock binding. More description can
+	be found in Documentation/devicetree/bindings/clock/clock-bindings.txt.
+
+Optional properties:
+- clock-latency: Clock transition latency in microsecond.
+
+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>;
+		operating-points = <
+				1000000 975000
+				800000  925000>;
+		clocks = <&clock 2>;
+		clock-latency = <100000>;
+	};
+
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index 030ddf6..7ed9c4a 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -77,6 +77,15 @@  config ARM_EXYNOS5250_CPUFREQ
 	  This adds the CPUFreq driver for Samsung EXYNOS5250
 	  SoC.
 
+config ARM_EXYNOS5440_CPUFREQ
+	def_bool SOC_EXYNOS5440
+	depends on HAVE_CLK && PM_OPP && OF
+	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_KIRKWOOD_CPUFREQ
 	def_bool ARCH_KIRKWOOD && OF
 	help
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 863fd18..c841438 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -52,6 +52,7 @@  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_KIRKWOOD_CPUFREQ)	+= kirkwood-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..2dc43b1
--- /dev/null
+++ b/drivers/cpufreq/exynos5440-cpufreq.c
@@ -0,0 +1,450 @@ 
+/*
+ * 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/cpu.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/opp.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;
+	unsigned int latency;
+	struct cpufreq_frequency_table *freq_table;
+	unsigned int freq_count;
+	struct device *dev;
+	struct work_struct irq_work;
+};
+
+static struct exynos_dvfs_data *dvfs_info;
+static DEFINE_MUTEX(cpufreq_lock);
+static struct cpufreq_freqs freqs;
+
+static int init_div_table(void)
+{
+	struct cpufreq_frequency_table *freq_tbl = dvfs_info->freq_table;
+	unsigned int tmp, clk_div, ema_div, freq, volt_id;
+	int i = 0;
+	struct opp *opp;
+
+	for (i = 0; freq_tbl[i].frequency != CPUFREQ_TABLE_END; i++) {
+
+		opp = opp_find_freq_exact(dvfs_info->dev,
+					freq_tbl[i].frequency * 1000, true);
+		if (IS_ERR(opp)) {
+			pr_err("failed to find valid OPP for %u KHZ\n",
+					freq_tbl[i].frequency);
+			return PTR_ERR(opp);
+		}
+
+		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 = opp_get_voltage(opp);
+		volt_id = (MAX_VOLTAGE - volt_id) / 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);
+	}
+
+	return 0;
+}
+
+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 performance 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");
+		/*Assign the highest frequency*/
+		i = 0;
+		dvfs_info->cur_frequency = freq_table[i].frequency;
+	}
+
+	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, 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 (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;
+
+	if (policy == NULL)
+		goto skip_work;
+
+	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 < dvfs_info->freq_count) {
+		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);
+skip_work:
+	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);
+		disable_irq_nosync(irq);
+		schedule_work(&dvfs_info->irq_work);
+	}
+	return IRQ_HANDLED;
+}
+
+static void exynos_sort_descend_freq_table(void)
+{
+	struct cpufreq_frequency_table *freq_tbl = dvfs_info->freq_table;
+	int i = 0, index;
+	unsigned int tmp_freq;
+
+	/*
+	 *Freq table is already in ascending order as it is created from
+	 *OPP library, so just swap the elements to make it descending.
+	 */
+	for (i = 0; i < dvfs_info->freq_count / 2; i++) {
+		index = dvfs_info->freq_count - i - 1;
+		tmp_freq = freq_tbl[i].frequency;
+		freq_tbl[i].frequency = freq_tbl[index].frequency;
+		freq_tbl[index].frequency = tmp_freq;
+	}
+}
+
+static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
+{
+
+	policy->cur = dvfs_info->cur_frequency;
+	cpufreq_frequency_table_get_attr(dvfs_info->freq_table, policy->cpu);
+
+	/* set the transition latency value */
+	policy->cpuinfo.transition_latency = dvfs_info->latency;
+
+	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;
+	struct device_node *np;
+
+	np =  of_find_compatible_node(NULL, NULL, "samsung,exynos5440-cpufreq");
+	if (IS_ERR(np))
+		return -ENODEV;
+
+	dvfs_info = kzalloc(sizeof(struct exynos_dvfs_data), GFP_KERNEL);
+	if (IS_ERR(dvfs_info)) {
+		ret = -ENOMEM;
+		goto err_mem_data;
+	}
+
+	dvfs_info->base = of_iomap(np, 0);
+	if (IS_ERR(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;
+	}
+
+	dvfs_info->dev = get_cpu_device(0);
+	if (IS_ERR(dvfs_info->dev)) {
+		pr_err("failed to get cpu0 device\n");
+		ret = -ENODEV;
+		goto err_irq_parse;
+	}
+
+	dvfs_info->dev->of_node = np;
+
+	ret = of_init_opp_table(dvfs_info->dev);
+	if (ret) {
+		pr_err("failed to init OPP table: %d\n", ret);
+		goto err_irq_parse;
+	}
+
+	ret = opp_init_cpufreq_table(dvfs_info->dev, &dvfs_info->freq_table);
+	if (ret) {
+		pr_err("failed to init cpufreq table: %d\n", ret);
+		goto err_irq_parse;
+	}
+	dvfs_info->freq_count = opp_get_opp_count(dvfs_info->dev);
+	exynos_sort_descend_freq_table();
+
+	if (of_property_read_u32(np, "clock-latency", &dvfs_info->latency))
+		dvfs_info->latency = DEF_TRANS_LATENCY;
+
+	dvfs_info->cpu_clk = of_clk_get(np, 0);
+	if (IS_ERR(dvfs_info->cpu_clk)) {
+		pr_err("Failed to get cpu clock\n");
+		ret = PTR_ERR(dvfs_info->cpu_clk);
+		goto err_clk_get;
+	}
+
+	dvfs_info->cur_frequency = clk_get_rate(dvfs_info->cpu_clk);
+	if (!dvfs_info->cur_frequency) {
+		pr_err("Failed to get clock rate\n");
+		ret = -EINVAL;
+		goto err_clk_get_rate;
+	}
+	dvfs_info->cur_frequency /= 1000;
+
+	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_clk_get_rate;
+	}
+
+	ret = init_div_table();
+	if (ret) {
+		pr_err("Failed to initialise div table\n");
+		goto err_div_table;
+	}
+
+	exynos_enable_dvfs();
+	ret = cpufreq_register_driver(&exynos_driver);
+	if (ret) {
+		pr_err("%s: failed to register cpufreq driver\n", __func__);
+		goto err_div_table;
+	}
+
+	of_node_put(np);
+
+	pr_info("exynos5440 DVFS initialised.\n");
+
+	return 0;
+
+err_div_table:
+	free_irq(dvfs_info->irq, dvfs_info);
+err_clk_get_rate:
+	clk_put(dvfs_info->cpu_clk);
+err_clk_get:
+	opp_free_cpufreq_table(dvfs_info->dev, &dvfs_info->freq_table);
+err_irq_parse:
+	iounmap(dvfs_info->base);
+err_map:
+	kfree(dvfs_info);
+err_mem_data:
+	of_node_put(np);
+	pr_err("%s: failed initialization\n", __func__);
+	return ret;
+}
+late_initcall(exynos_cpufreq_init);