diff mbox

[2/5] ARM: vexpress/TC2: add support for CPU DVFS

Message ID 1381931563-16785-3-git-send-email-Sudeep.KarkadaNagesha@arm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Sudeep KarkadaNagesha Oct. 16, 2013, 1:52 p.m. UTC
From: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>

SPC(Serial Power Controller) on TC2 also controls the CPU performance
operating points which is essential to provide CPU DVFS. The M3
microcontroller provides two sets of eight performance values, one set
for each cluster (CA15 or CA7). Each of this value contains the
frequency(kHz) and voltage(mV) at that performance level. It expects
these performance level to be passed through the SPC PERF_LVL registers.

This patch adds support to populate these performance levels from M3,
build the mapping to CPU OPPs at the boot and then use it to get and
set the CPU performance level runtime.

Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Cc: Pawel Moll <Pawel.Moll@arm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
---
 arch/arm/mach-vexpress/Kconfig  |   2 +
 arch/arm/mach-vexpress/spc.c    | 240 +++++++++++++++++++++++++++++++++++++++-
 arch/arm/mach-vexpress/spc.h    |   2 +-
 arch/arm/mach-vexpress/tc2_pm.c |   7 +-
 4 files changed, 247 insertions(+), 4 deletions(-)

Comments

Nicolas Pitre Oct. 18, 2013, 6:27 p.m. UTC | #1
On Wed, 16 Oct 2013, Sudeep KarkadaNagesha wrote:

> From: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
> 
> SPC(Serial Power Controller) on TC2 also controls the CPU performance
> operating points which is essential to provide CPU DVFS. The M3
> microcontroller provides two sets of eight performance values, one set
> for each cluster (CA15 or CA7). Each of this value contains the
> frequency(kHz) and voltage(mV) at that performance level. It expects
> these performance level to be passed through the SPC PERF_LVL registers.
> 
> This patch adds support to populate these performance levels from M3,
> build the mapping to CPU OPPs at the boot and then use it to get and
> set the CPU performance level runtime.
> 
> Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
> Cc: Pawel Moll <Pawel.Moll@arm.com>
> Cc: Viresh Kumar <viresh.kumar@linaro.org>

Minor comments below.  With those addressed, you may add

Acked-by: Nicolas Pitre <nico@linaro.org>

> ---
>  arch/arm/mach-vexpress/Kconfig  |   2 +
>  arch/arm/mach-vexpress/spc.c    | 240 +++++++++++++++++++++++++++++++++++++++-
>  arch/arm/mach-vexpress/spc.h    |   2 +-
>  arch/arm/mach-vexpress/tc2_pm.c |   7 +-
>  4 files changed, 247 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm/mach-vexpress/Kconfig b/arch/arm/mach-vexpress/Kconfig
> index 3657954..5989187 100644
> --- a/arch/arm/mach-vexpress/Kconfig
> +++ b/arch/arm/mach-vexpress/Kconfig
> @@ -1,5 +1,7 @@
>  config ARCH_VEXPRESS
>  	bool "ARM Ltd. Versatile Express family" if ARCH_MULTI_V7
> +	select ARCH_HAS_CPUFREQ
> +	select ARCH_HAS_OPP
>  	select ARCH_REQUIRE_GPIOLIB
>  	select ARM_AMBA
>  	select ARM_GIC

This is probably a bit too wide a selection for all CONFIG_ARCH_VEXPRESS 
targets.

I'd suggest creating a new CONFIG_VEXPRESS_SPC entry, making the build 
of spc.o depend on it, and that config entry could select
ARCH_HAS_CPUFREQ, ARCH_HAS_OPP and (as discussed in private) PM_OPP.  

Then this VEXPRESS_SPC would be selected by ARCH_VEXPRESS_TC2_PM.

Also the config dependency for ARM_VEXPRESS_SPC_CPUFREQ (in the later 
patch) would be better represented by VEXPRESS_SPC rather than 
ARCH_VEXPRESS_TC2_PM.

> diff --git a/arch/arm/mach-vexpress/spc.c b/arch/arm/mach-vexpress/spc.c
> index eefb029..ef7e652 100644
> --- a/arch/arm/mach-vexpress/spc.c
> +++ b/arch/arm/mach-vexpress/spc.c
> @@ -17,14 +17,26 @@
>   * GNU General Public License for more details.
>   */
>  
> +#include <linux/delay.h>
>  #include <linux/err.h>
> +#include <linux/interrupt.h>
>  #include <linux/io.h>
> +#include <linux/opp.h>
>  #include <linux/slab.h>
> +#include <linux/semaphore.h>
>  
>  #include <asm/cacheflush.h>
>  
>  #define SPCLOG "vexpress-spc: "
>  
> +#define PERF_LVL_A15		0x00
> +#define PERF_REQ_A15		0x04
> +#define PERF_LVL_A7		0x08
> +#define PERF_REQ_A7		0x0c
> +#define COMMS			0x10
> +#define COMMS_REQ		0x14
> +#define PWC_STATUS		0x18
> +#define PWC_FLAG		0x1c

Maybe a blank line here?

>  /* SPC wake-up IRQs status and mask */
>  #define WAKE_INT_MASK		0x24
>  #define WAKE_INT_RAW		0x28
> @@ -35,6 +47,18 @@
>  /* SPC per-CPU mailboxes */
>  #define A15_BX_ADDR0		0x68
>  #define A7_BX_ADDR0		0x78

Ditto.

> +/* SPC system config interface registers */
> +#define SYSCFG_WDATA		0x70
> +#define SYSCFG_RDATA		0x74
> +
> +/* A15/A7 OPP virtual register base */
> +#define A15_PERFVAL_BASE	0xC10
> +#define A7_PERFVAL_BASE		0xC30
> +
> +/* Config interface control bits */
> +#define SYSCFG_START		(1 << 31)
> +#define SYSCFG_SCC		(6 << 20)
> +#define SYSCFG_STAT		(14 << 20)
>  
>  /* wake-up interrupt masks */
>  #define GBL_WAKEUP_INT_MSK	(0x3 << 10)
> @@ -42,6 +66,26 @@
>  /* TC2 static dual-cluster configuration */
>  #define MAX_CLUSTERS		2
>  
> +/*
> + * Even though the SPC takes max 3-5 ms to complete any OPP/COMMS
> + * operation, the operation could start just before jiffie is about
> + * to be incremented. So setting timeout value of 20ms = 2jiffies@100Hz
> + */
> +#define TIMEOUT_US	20000
> +
> +#define MAX_OPPS	8
> +#define CA15_DVFS	0
> +#define CA7_DVFS	1
> +#define SPC_SYS_CFG	2
> +#define STAT_COMPLETE(type)	((1 << 0) << (type << 2))
> +#define STAT_ERR(type)		((1 << 1) << (type << 2))
> +#define RESPONSE_MASK(type)	(STAT_COMPLETE(type) | STAT_ERR(type))
> +
> +struct ve_spc_opp {
> +	unsigned long freq;
> +	unsigned long u_volt;
> +};
> +
>  struct ve_spc_drvdata {
>  	void __iomem *baseaddr;
>  	/*
> @@ -49,6 +93,12 @@ struct ve_spc_drvdata {
>  	 * It corresponds to A15 processors MPIDR[15:8] bitfield
>  	 */
>  	u32 a15_clusid;
> +	uint32_t cur_rsp_mask;
> +	uint32_t cur_rsp_stat;
> +	struct semaphore sem;
> +	struct completion done;
> +	struct ve_spc_opp *opps[MAX_CLUSTERS];
> +	int num_opps[MAX_CLUSTERS];
>  };
>  
>  static struct ve_spc_drvdata *info;
> @@ -157,8 +207,177 @@ void ve_spc_powerdown(u32 cluster, bool enable)
>  	writel_relaxed(enable, info->baseaddr + pwdrn_reg);
>  }
>  
> -int __init ve_spc_init(void __iomem *baseaddr, u32 a15_clusid)
> +static int ve_spc_get_performance(int cluster, u32 *freq)
> +{
> +	struct ve_spc_opp *opps = info->opps[cluster];
> +	u32 perf_cfg_reg = 0;
> +	int perf;
> +
> +	perf_cfg_reg = cluster_is_a15(cluster) ? PERF_LVL_A15 : PERF_LVL_A7;
> +
> +	perf = readl_relaxed(info->baseaddr + perf_cfg_reg);
> +	opps += perf;

This might be a good idea to validate the hardware returned index before 
dereferencing memory i.e "if (perf >= info->num_opps[cluster]) ..." with 
perf declared as an unsigned int.

> +	*freq = opps->freq;
> +
> +	return 0;
> +}
> +
> +/* find closest match to given frequency in OPP table */
> +static int ve_spc_round_performance(int cluster, u32 freq)
> +{
> +	int idx, max_opp = info->num_opps[cluster];
> +	struct ve_spc_opp *opps = info->opps[cluster];
> +	u32 fmin = 0, fmax = ~0, ftmp;
> +
> +	freq /= 1000; /* OPP entries in kHz */
> +	for (idx = 0; idx < max_opp; idx++, opps++) {
> +		ftmp = opps->freq;
> +		if (ftmp >= freq) {
> +			if (ftmp <= fmax)
> +				fmax = ftmp;
> +		} else {
> +			if (ftmp >= fmin)
> +				fmin = ftmp;
> +		}
> +	}
> +	if (fmax != ~0)
> +		return fmax * 1000;
> +	else
> +		return fmin * 1000;
> +}
> +
> +static int ve_spc_find_performance_index(int cluster, u32 freq)
> +{
> +	int idx, max_opp = info->num_opps[cluster];
> +	struct ve_spc_opp *opps = info->opps[cluster];
> +
> +	for (idx = 0; idx < max_opp; idx++, opps++)
> +		if (opps->freq == freq)
> +			break;
> +	return (idx == max_opp) ? -EINVAL : idx;
> +}
> +
> +static int ve_spc_waitforcompletion(int req_type)
> +{
> +	int ret = wait_for_completion_interruptible_timeout(
> +			&info->done, usecs_to_jiffies(TIMEOUT_US));
> +	if (ret == 0)
> +		ret = -ETIMEDOUT;
> +	else if (ret > 0)
> +		ret = info->cur_rsp_stat & STAT_COMPLETE(req_type) ? 0 : -EIO;
> +	return ret;
> +}
> +
> +static int ve_spc_set_performance(int cluster, u32 freq)
> +{
> +	u32 perf_cfg_reg, perf_stat_reg;
> +	int ret, perf, req_type;
> +
> +	if (cluster_is_a15(cluster)) {
> +		req_type = CA15_DVFS;
> +		perf_cfg_reg = PERF_LVL_A15;
> +		perf_stat_reg = PERF_REQ_A15;
> +	} else {
> +		req_type = CA7_DVFS;
> +		perf_cfg_reg = PERF_LVL_A7;
> +		perf_stat_reg = PERF_REQ_A7;
> +	}
> +
> +	perf = ve_spc_find_performance_index(cluster, freq);
> +
> +	if (perf < 0)
> +		return perf;
> +
> +	if (down_timeout(&info->sem, usecs_to_jiffies(TIMEOUT_US)))
> +		return -ETIME;
> +
> +	init_completion(&info->done);
> +	info->cur_rsp_mask = RESPONSE_MASK(req_type);
> +
> +	writel(perf, info->baseaddr + perf_cfg_reg);
> +	ret = ve_spc_waitforcompletion(req_type);
> +
> +	info->cur_rsp_mask = 0;
> +	up(&info->sem);
> +
> +	return ret;
> +}
> +
> +static int ve_spc_read_sys_cfg(int func, int offset, uint32_t *data)
> +{
> +	int ret;
> +
> +	if (down_timeout(&info->sem, usecs_to_jiffies(TIMEOUT_US)))
> +		return -ETIME;
> +
> +	init_completion(&info->done);
> +	info->cur_rsp_mask = RESPONSE_MASK(SPC_SYS_CFG);
> +
> +	/* Set the control value */
> +	writel(SYSCFG_START | func | offset >> 2, info->baseaddr + COMMS);
> +	ret = ve_spc_waitforcompletion(SPC_SYS_CFG);
> +
> +	if (ret == 0)
> +		*data = readl(info->baseaddr + SYSCFG_RDATA);
> +
> +	info->cur_rsp_mask = 0;
> +	up(&info->sem);
> +
> +	return ret;
> +}
> +
> +static irqreturn_t ve_spc_irq_handler(int irq, void *data)
> +{
> +	struct ve_spc_drvdata *drv_data = data;
> +	uint32_t status = readl_relaxed(drv_data->baseaddr + PWC_STATUS);
> +
> +	if (info->cur_rsp_mask & status) {
> +		info->cur_rsp_stat = status;
> +		complete(&drv_data->done);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +/*
> + *  +--------------------------+
> + *  | 31      20 | 19        0 |
> + *  +--------------------------+
> + *  |   u_volt   |  freq(kHz)  |
> + *  +--------------------------+
> + */
> +#define MULT_FACTOR	20
> +#define VOLT_SHIFT	20
> +#define FREQ_MASK	(0xFFFFF)
> +static int ve_spc_populate_opps(uint32_t cluster)
> +{
> +	uint32_t data = 0, off, ret, idx;
> +	struct ve_spc_opp *opps;
> +
> +	opps = kzalloc(sizeof(*opps) * MAX_OPPS, GFP_KERNEL);
> +	if (!opps)
> +		return -ENOMEM;
> +
> +	info->opps[cluster] = opps;
> +
> +	off = cluster_is_a15(cluster) ? A15_PERFVAL_BASE : A7_PERFVAL_BASE;
> +	for (idx = 0; idx < MAX_OPPS; idx++, off += 4, opps++) {
> +		ret = ve_spc_read_sys_cfg(SYSCFG_SCC, off, &data);
> +		if (!ret) {
> +			opps->freq = (data & FREQ_MASK) * MULT_FACTOR;
> +			opps->u_volt = data >> VOLT_SHIFT;
> +		} else {
> +			break;
> +		}
> +	}
> +	info->num_opps[cluster] = idx;
> +
> +	return ret;
> +}
> +
> +int __init ve_spc_init(void __iomem *baseaddr, u32 a15_clusid, int irq)
>  {
> +	int ret;
>  	info = kzalloc(sizeof(*info), GFP_KERNEL);
>  	if (!info) {
>  		pr_err(SPCLOG "unable to allocate mem\n");
> @@ -168,6 +387,25 @@ int __init ve_spc_init(void __iomem *baseaddr, u32 a15_clusid)
>  	info->baseaddr = baseaddr;
>  	info->a15_clusid = a15_clusid;
>  
> +	if (irq <= 0) {
> +		pr_err(SPCLOG "Invalid IRQ %d\n", irq);
> +		kfree(info);
> +		return -EINVAL;
> +	}
> +
> +	init_completion(&info->done);
> +
> +	readl_relaxed(info->baseaddr + PWC_STATUS);
> +
> +	ret = request_irq(irq, ve_spc_irq_handler, IRQF_TRIGGER_HIGH
> +				| IRQF_ONESHOT, "vexpress-spc", info);
> +	if (ret) {
> +		pr_err(SPCLOG "IRQ %d request failed\n", irq);
> +		kfree(info);
> +		return -ENODEV;
> +	}
> +
> +	sema_init(&info->sem, 1);
>  	/*
>  	 * Multi-cluster systems may need this data when non-coherent, during
>  	 * cluster power-up/power-down. Make sure driver info reaches main
> diff --git a/arch/arm/mach-vexpress/spc.h b/arch/arm/mach-vexpress/spc.h
> index 5f7e4a4..dbd44c3 100644
> --- a/arch/arm/mach-vexpress/spc.h
> +++ b/arch/arm/mach-vexpress/spc.h
> @@ -15,7 +15,7 @@
>  #ifndef __SPC_H_
>  #define __SPC_H_
>  
> -int __init ve_spc_init(void __iomem *base, u32 a15_clusid);
> +int __init ve_spc_init(void __iomem *base, u32 a15_clusid, int irq);
>  void ve_spc_global_wakeup_irq(bool set);
>  void ve_spc_cpu_wakeup_irq(u32 cluster, u32 cpu, bool set);
>  void ve_spc_set_resume_addr(u32 cluster, u32 cpu, u32 addr);
> diff --git a/arch/arm/mach-vexpress/tc2_pm.c b/arch/arm/mach-vexpress/tc2_pm.c
> index e6eb481..d38130a 100644
> --- a/arch/arm/mach-vexpress/tc2_pm.c
> +++ b/arch/arm/mach-vexpress/tc2_pm.c
> @@ -16,6 +16,7 @@
>  #include <linux/io.h>
>  #include <linux/kernel.h>
>  #include <linux/of_address.h>
> +#include <linux/of_irq.h>
>  #include <linux/spinlock.h>
>  #include <linux/errno.h>
>  #include <linux/irqchip/arm-gic.h>
> @@ -311,7 +312,7 @@ static void __naked tc2_pm_power_up_setup(unsigned int affinity_level)
>  
>  static int __init tc2_pm_init(void)
>  {
> -	int ret;
> +	int ret, irq;
>  	void __iomem *scc;
>  	u32 a15_cluster_id, a7_cluster_id, sys_info;
>  	struct device_node *np;
> @@ -336,13 +337,15 @@ static int __init tc2_pm_init(void)
>  	tc2_nr_cpus[a15_cluster_id] = (sys_info >> 16) & 0xf;
>  	tc2_nr_cpus[a7_cluster_id] = (sys_info >> 20) & 0xf;
>  
> +	irq = irq_of_parse_and_map(np, 0);
> +
>  	/*
>  	 * A subset of the SCC registers is also used to communicate
>  	 * with the SPC (power controller). We need to be able to
>  	 * drive it very early in the boot process to power up
>  	 * processors, so we initialize the SPC driver here.
>  	 */
> -	ret = ve_spc_init(scc + SPC_BASE, a15_cluster_id);
> +	ret = ve_spc_init(scc + SPC_BASE, a15_cluster_id, irq);
>  	if (ret)
>  		return ret;
>  
> -- 
> 1.8.1.2
>
diff mbox

Patch

diff --git a/arch/arm/mach-vexpress/Kconfig b/arch/arm/mach-vexpress/Kconfig
index 3657954..5989187 100644
--- a/arch/arm/mach-vexpress/Kconfig
+++ b/arch/arm/mach-vexpress/Kconfig
@@ -1,5 +1,7 @@ 
 config ARCH_VEXPRESS
 	bool "ARM Ltd. Versatile Express family" if ARCH_MULTI_V7
+	select ARCH_HAS_CPUFREQ
+	select ARCH_HAS_OPP
 	select ARCH_REQUIRE_GPIOLIB
 	select ARM_AMBA
 	select ARM_GIC
diff --git a/arch/arm/mach-vexpress/spc.c b/arch/arm/mach-vexpress/spc.c
index eefb029..ef7e652 100644
--- a/arch/arm/mach-vexpress/spc.c
+++ b/arch/arm/mach-vexpress/spc.c
@@ -17,14 +17,26 @@ 
  * GNU General Public License for more details.
  */
 
+#include <linux/delay.h>
 #include <linux/err.h>
+#include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/opp.h>
 #include <linux/slab.h>
+#include <linux/semaphore.h>
 
 #include <asm/cacheflush.h>
 
 #define SPCLOG "vexpress-spc: "
 
+#define PERF_LVL_A15		0x00
+#define PERF_REQ_A15		0x04
+#define PERF_LVL_A7		0x08
+#define PERF_REQ_A7		0x0c
+#define COMMS			0x10
+#define COMMS_REQ		0x14
+#define PWC_STATUS		0x18
+#define PWC_FLAG		0x1c
 /* SPC wake-up IRQs status and mask */
 #define WAKE_INT_MASK		0x24
 #define WAKE_INT_RAW		0x28
@@ -35,6 +47,18 @@ 
 /* SPC per-CPU mailboxes */
 #define A15_BX_ADDR0		0x68
 #define A7_BX_ADDR0		0x78
+/* SPC system config interface registers */
+#define SYSCFG_WDATA		0x70
+#define SYSCFG_RDATA		0x74
+
+/* A15/A7 OPP virtual register base */
+#define A15_PERFVAL_BASE	0xC10
+#define A7_PERFVAL_BASE		0xC30
+
+/* Config interface control bits */
+#define SYSCFG_START		(1 << 31)
+#define SYSCFG_SCC		(6 << 20)
+#define SYSCFG_STAT		(14 << 20)
 
 /* wake-up interrupt masks */
 #define GBL_WAKEUP_INT_MSK	(0x3 << 10)
@@ -42,6 +66,26 @@ 
 /* TC2 static dual-cluster configuration */
 #define MAX_CLUSTERS		2
 
+/*
+ * Even though the SPC takes max 3-5 ms to complete any OPP/COMMS
+ * operation, the operation could start just before jiffie is about
+ * to be incremented. So setting timeout value of 20ms = 2jiffies@100Hz
+ */
+#define TIMEOUT_US	20000
+
+#define MAX_OPPS	8
+#define CA15_DVFS	0
+#define CA7_DVFS	1
+#define SPC_SYS_CFG	2
+#define STAT_COMPLETE(type)	((1 << 0) << (type << 2))
+#define STAT_ERR(type)		((1 << 1) << (type << 2))
+#define RESPONSE_MASK(type)	(STAT_COMPLETE(type) | STAT_ERR(type))
+
+struct ve_spc_opp {
+	unsigned long freq;
+	unsigned long u_volt;
+};
+
 struct ve_spc_drvdata {
 	void __iomem *baseaddr;
 	/*
@@ -49,6 +93,12 @@  struct ve_spc_drvdata {
 	 * It corresponds to A15 processors MPIDR[15:8] bitfield
 	 */
 	u32 a15_clusid;
+	uint32_t cur_rsp_mask;
+	uint32_t cur_rsp_stat;
+	struct semaphore sem;
+	struct completion done;
+	struct ve_spc_opp *opps[MAX_CLUSTERS];
+	int num_opps[MAX_CLUSTERS];
 };
 
 static struct ve_spc_drvdata *info;
@@ -157,8 +207,177 @@  void ve_spc_powerdown(u32 cluster, bool enable)
 	writel_relaxed(enable, info->baseaddr + pwdrn_reg);
 }
 
-int __init ve_spc_init(void __iomem *baseaddr, u32 a15_clusid)
+static int ve_spc_get_performance(int cluster, u32 *freq)
+{
+	struct ve_spc_opp *opps = info->opps[cluster];
+	u32 perf_cfg_reg = 0;
+	int perf;
+
+	perf_cfg_reg = cluster_is_a15(cluster) ? PERF_LVL_A15 : PERF_LVL_A7;
+
+	perf = readl_relaxed(info->baseaddr + perf_cfg_reg);
+	opps += perf;
+	*freq = opps->freq;
+
+	return 0;
+}
+
+/* find closest match to given frequency in OPP table */
+static int ve_spc_round_performance(int cluster, u32 freq)
+{
+	int idx, max_opp = info->num_opps[cluster];
+	struct ve_spc_opp *opps = info->opps[cluster];
+	u32 fmin = 0, fmax = ~0, ftmp;
+
+	freq /= 1000; /* OPP entries in kHz */
+	for (idx = 0; idx < max_opp; idx++, opps++) {
+		ftmp = opps->freq;
+		if (ftmp >= freq) {
+			if (ftmp <= fmax)
+				fmax = ftmp;
+		} else {
+			if (ftmp >= fmin)
+				fmin = ftmp;
+		}
+	}
+	if (fmax != ~0)
+		return fmax * 1000;
+	else
+		return fmin * 1000;
+}
+
+static int ve_spc_find_performance_index(int cluster, u32 freq)
+{
+	int idx, max_opp = info->num_opps[cluster];
+	struct ve_spc_opp *opps = info->opps[cluster];
+
+	for (idx = 0; idx < max_opp; idx++, opps++)
+		if (opps->freq == freq)
+			break;
+	return (idx == max_opp) ? -EINVAL : idx;
+}
+
+static int ve_spc_waitforcompletion(int req_type)
+{
+	int ret = wait_for_completion_interruptible_timeout(
+			&info->done, usecs_to_jiffies(TIMEOUT_US));
+	if (ret == 0)
+		ret = -ETIMEDOUT;
+	else if (ret > 0)
+		ret = info->cur_rsp_stat & STAT_COMPLETE(req_type) ? 0 : -EIO;
+	return ret;
+}
+
+static int ve_spc_set_performance(int cluster, u32 freq)
+{
+	u32 perf_cfg_reg, perf_stat_reg;
+	int ret, perf, req_type;
+
+	if (cluster_is_a15(cluster)) {
+		req_type = CA15_DVFS;
+		perf_cfg_reg = PERF_LVL_A15;
+		perf_stat_reg = PERF_REQ_A15;
+	} else {
+		req_type = CA7_DVFS;
+		perf_cfg_reg = PERF_LVL_A7;
+		perf_stat_reg = PERF_REQ_A7;
+	}
+
+	perf = ve_spc_find_performance_index(cluster, freq);
+
+	if (perf < 0)
+		return perf;
+
+	if (down_timeout(&info->sem, usecs_to_jiffies(TIMEOUT_US)))
+		return -ETIME;
+
+	init_completion(&info->done);
+	info->cur_rsp_mask = RESPONSE_MASK(req_type);
+
+	writel(perf, info->baseaddr + perf_cfg_reg);
+	ret = ve_spc_waitforcompletion(req_type);
+
+	info->cur_rsp_mask = 0;
+	up(&info->sem);
+
+	return ret;
+}
+
+static int ve_spc_read_sys_cfg(int func, int offset, uint32_t *data)
+{
+	int ret;
+
+	if (down_timeout(&info->sem, usecs_to_jiffies(TIMEOUT_US)))
+		return -ETIME;
+
+	init_completion(&info->done);
+	info->cur_rsp_mask = RESPONSE_MASK(SPC_SYS_CFG);
+
+	/* Set the control value */
+	writel(SYSCFG_START | func | offset >> 2, info->baseaddr + COMMS);
+	ret = ve_spc_waitforcompletion(SPC_SYS_CFG);
+
+	if (ret == 0)
+		*data = readl(info->baseaddr + SYSCFG_RDATA);
+
+	info->cur_rsp_mask = 0;
+	up(&info->sem);
+
+	return ret;
+}
+
+static irqreturn_t ve_spc_irq_handler(int irq, void *data)
+{
+	struct ve_spc_drvdata *drv_data = data;
+	uint32_t status = readl_relaxed(drv_data->baseaddr + PWC_STATUS);
+
+	if (info->cur_rsp_mask & status) {
+		info->cur_rsp_stat = status;
+		complete(&drv_data->done);
+	}
+
+	return IRQ_HANDLED;
+}
+
+/*
+ *  +--------------------------+
+ *  | 31      20 | 19        0 |
+ *  +--------------------------+
+ *  |   u_volt   |  freq(kHz)  |
+ *  +--------------------------+
+ */
+#define MULT_FACTOR	20
+#define VOLT_SHIFT	20
+#define FREQ_MASK	(0xFFFFF)
+static int ve_spc_populate_opps(uint32_t cluster)
+{
+	uint32_t data = 0, off, ret, idx;
+	struct ve_spc_opp *opps;
+
+	opps = kzalloc(sizeof(*opps) * MAX_OPPS, GFP_KERNEL);
+	if (!opps)
+		return -ENOMEM;
+
+	info->opps[cluster] = opps;
+
+	off = cluster_is_a15(cluster) ? A15_PERFVAL_BASE : A7_PERFVAL_BASE;
+	for (idx = 0; idx < MAX_OPPS; idx++, off += 4, opps++) {
+		ret = ve_spc_read_sys_cfg(SYSCFG_SCC, off, &data);
+		if (!ret) {
+			opps->freq = (data & FREQ_MASK) * MULT_FACTOR;
+			opps->u_volt = data >> VOLT_SHIFT;
+		} else {
+			break;
+		}
+	}
+	info->num_opps[cluster] = idx;
+
+	return ret;
+}
+
+int __init ve_spc_init(void __iomem *baseaddr, u32 a15_clusid, int irq)
 {
+	int ret;
 	info = kzalloc(sizeof(*info), GFP_KERNEL);
 	if (!info) {
 		pr_err(SPCLOG "unable to allocate mem\n");
@@ -168,6 +387,25 @@  int __init ve_spc_init(void __iomem *baseaddr, u32 a15_clusid)
 	info->baseaddr = baseaddr;
 	info->a15_clusid = a15_clusid;
 
+	if (irq <= 0) {
+		pr_err(SPCLOG "Invalid IRQ %d\n", irq);
+		kfree(info);
+		return -EINVAL;
+	}
+
+	init_completion(&info->done);
+
+	readl_relaxed(info->baseaddr + PWC_STATUS);
+
+	ret = request_irq(irq, ve_spc_irq_handler, IRQF_TRIGGER_HIGH
+				| IRQF_ONESHOT, "vexpress-spc", info);
+	if (ret) {
+		pr_err(SPCLOG "IRQ %d request failed\n", irq);
+		kfree(info);
+		return -ENODEV;
+	}
+
+	sema_init(&info->sem, 1);
 	/*
 	 * Multi-cluster systems may need this data when non-coherent, during
 	 * cluster power-up/power-down. Make sure driver info reaches main
diff --git a/arch/arm/mach-vexpress/spc.h b/arch/arm/mach-vexpress/spc.h
index 5f7e4a4..dbd44c3 100644
--- a/arch/arm/mach-vexpress/spc.h
+++ b/arch/arm/mach-vexpress/spc.h
@@ -15,7 +15,7 @@ 
 #ifndef __SPC_H_
 #define __SPC_H_
 
-int __init ve_spc_init(void __iomem *base, u32 a15_clusid);
+int __init ve_spc_init(void __iomem *base, u32 a15_clusid, int irq);
 void ve_spc_global_wakeup_irq(bool set);
 void ve_spc_cpu_wakeup_irq(u32 cluster, u32 cpu, bool set);
 void ve_spc_set_resume_addr(u32 cluster, u32 cpu, u32 addr);
diff --git a/arch/arm/mach-vexpress/tc2_pm.c b/arch/arm/mach-vexpress/tc2_pm.c
index e6eb481..d38130a 100644
--- a/arch/arm/mach-vexpress/tc2_pm.c
+++ b/arch/arm/mach-vexpress/tc2_pm.c
@@ -16,6 +16,7 @@ 
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/of_address.h>
+#include <linux/of_irq.h>
 #include <linux/spinlock.h>
 #include <linux/errno.h>
 #include <linux/irqchip/arm-gic.h>
@@ -311,7 +312,7 @@  static void __naked tc2_pm_power_up_setup(unsigned int affinity_level)
 
 static int __init tc2_pm_init(void)
 {
-	int ret;
+	int ret, irq;
 	void __iomem *scc;
 	u32 a15_cluster_id, a7_cluster_id, sys_info;
 	struct device_node *np;
@@ -336,13 +337,15 @@  static int __init tc2_pm_init(void)
 	tc2_nr_cpus[a15_cluster_id] = (sys_info >> 16) & 0xf;
 	tc2_nr_cpus[a7_cluster_id] = (sys_info >> 20) & 0xf;
 
+	irq = irq_of_parse_and_map(np, 0);
+
 	/*
 	 * A subset of the SCC registers is also used to communicate
 	 * with the SPC (power controller). We need to be able to
 	 * drive it very early in the boot process to power up
 	 * processors, so we initialize the SPC driver here.
 	 */
-	ret = ve_spc_init(scc + SPC_BASE, a15_cluster_id);
+	ret = ve_spc_init(scc + SPC_BASE, a15_cluster_id, irq);
 	if (ret)
 		return ret;