On 08/22/2014 07:02 AM, Nishanth Menon wrote:
From: Santosh Shilimkar <santosh.shilim...@ti.com>

Add OMAP5/DRA74/72 CPUIDLE support.

This patch adds MPUSS low power states in cpuidle.

         C1 - CPU0 WFI + CPU1 WFI + MPU ON
         C2 - CPU0 RET + CPU1 RET + MPU CSWR

Tested on DRA74/72-EVM for C1 and C2 states.

NOTE: DRA7 does not do voltage scaling as part of retention transition
and has Mercury which speeds up transition paths - Latency numbers are
based on measurements done by toggling GPIOs.

Signed-off-by: Santosh Shilimkar <santosh.shilim...@ti.com>
[ j-keer...@ti.com rework on 3.14]
Signed-off-by: Keerthy <j-keer...@ti.com>
[n...@ti.com: updates based on profiling, OMAP5 squashed]
Signed-off-by: Nishanth Menon <n...@ti.com>
---
  arch/arm/mach-omap2/cpuidle44xx.c |   82 ++++++++++++++++++++++++++++++++++++-
  arch/arm/mach-omap2/pm44xx.c      |    2 +-
  2 files changed, 82 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-omap2/cpuidle44xx.c 
b/arch/arm/mach-omap2/cpuidle44xx.c
index 2498ab0..8ad4f44 100644
--- a/arch/arm/mach-omap2/cpuidle44xx.c
+++ b/arch/arm/mach-omap2/cpuidle44xx.c
@@ -22,6 +22,7 @@
  #include "common.h"
  #include "pm.h"
  #include "prm.h"
+#include "soc.h"
  #include "clockdomain.h"

  #define MAX_CPUS      2
@@ -31,6 +32,7 @@ struct idle_statedata {
        u32 cpu_state;
        u32 mpu_logic_state;
        u32 mpu_state;
+       u32 mpu_state_vote;
  };

  static struct idle_statedata omap4_idle_data[] = {
@@ -51,12 +53,26 @@ static struct idle_statedata omap4_idle_data[] = {
        },
  };

+static struct idle_statedata dra7_idle_data[] = {
+       {
+               .cpu_state = PWRDM_POWER_ON,
+               .mpu_state = PWRDM_POWER_ON,
+               .mpu_logic_state = PWRDM_POWER_ON,
+       },
+       {
+               .cpu_state = PWRDM_POWER_RET,
+               .mpu_state = PWRDM_POWER_RET,
+               .mpu_logic_state = PWRDM_POWER_RET,
+       },
+};
+
  static struct powerdomain *mpu_pd, *cpu_pd[MAX_CPUS];
  static struct clockdomain *cpu_clkdm[MAX_CPUS];

  static atomic_t abort_barrier;
  static bool cpu_done[MAX_CPUS];
  static struct idle_statedata *state_ptr = &omap4_idle_data[0];
+static DEFINE_RAW_SPINLOCK(mpu_lock);

  /* Private functions */

@@ -78,6 +94,32 @@ static int omap_enter_idle_simple(struct cpuidle_device *dev,
        return index;
  }

+static int omap_enter_idle_smp(struct cpuidle_device *dev,
+                              struct cpuidle_driver *drv,
+                              int index)
+{
+       struct idle_statedata *cx = state_ptr + index;
+       unsigned long flag;
+
+       raw_spin_lock_irqsave(&mpu_lock, flag);

Why do you need this spin_lock_irqsave ? Aren't the local irqs already disabled ?

+       cx->mpu_state_vote++;
+       if (cx->mpu_state_vote == num_online_cpus()) {
+               pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state);
+               omap_set_pwrdm_state(mpu_pd, cx->mpu_state);
+       }
+       raw_spin_unlock_irqrestore(&mpu_lock, flag);
+
+       omap4_enter_lowpower(dev->cpu, cx->cpu_state);
+
+       raw_spin_lock_irqsave(&mpu_lock, flag);
+       if (cx->mpu_state_vote == num_online_cpus())
+               omap_set_pwrdm_state(mpu_pd, PWRDM_POWER_ON);
+       cx->mpu_state_vote--;
+       raw_spin_unlock_irqrestore(&mpu_lock, flag);

I am not sure that will work. What happens if a cpu exits idle and then re-enter idle immediately ?

Could you try a long run of this little program:

https://git.linaro.org/power/pm-qa.git/blob/HEAD:/cpuidle/cpuidle_killer.c

+       return index;
+}
+
  static int omap_enter_idle_coupled(struct cpuidle_device *dev,
                        struct cpuidle_driver *drv,
                        int index)
@@ -224,6 +266,34 @@ static struct cpuidle_driver omap4_idle_driver = {
        .safe_state_index = 0,
  };

+static struct cpuidle_driver dra7_idle_driver = {
+       .name                           = "dra7_idle",
+       .owner                          = THIS_MODULE,
+       .states = {
+               {
+                       /* C1 - CPU0 ON + CPU1 ON + MPU ON */
+                       .exit_latency = 2 + 2,
+                       .target_residency = 5,
+                       .flags = CPUIDLE_FLAG_TIME_VALID,
+                       .enter = omap_enter_idle_simple,
+                       .name = "C1",
+                       .desc = "CPUx WFI, MPUSS ON"
+               },
+               {
+                       /* C2 - CPU0 RET + CPU1 RET + MPU CSWR */
+                       .exit_latency = 48 + 60,
+                       .target_residency = 100,
+                       .flags = CPUIDLE_FLAG_TIME_VALID
+                                       | CPUIDLE_FLAG_TIMER_STOP,
+                       .enter = omap_enter_idle_smp,
+                       .name = "C2",
+                       .desc = "CPUx CSWR, MPUSS CSWR",
+               },
+       },
+       .state_count = ARRAY_SIZE(dra7_idle_data),
+       .safe_state_index = 0,
+};
+
  /* Public functions */

  /**
@@ -234,6 +304,16 @@ static struct cpuidle_driver omap4_idle_driver = {
   */
  int __init omap4_idle_init(void)
  {
+       struct cpuidle_driver *idle_driver;
+
+       if (soc_is_dra7xx() || soc_is_omap54xx()) {
+               state_ptr = &dra7_idle_data[0];
+               idle_driver = &dra7_idle_driver;
+       } else {
+               state_ptr = &omap4_idle_data[0];
+               idle_driver = &omap4_idle_driver;
+       }
+
        mpu_pd = pwrdm_lookup("mpu_pwrdm");
        cpu_pd[0] = pwrdm_lookup("cpu0_pwrdm");
        cpu_pd[1] = pwrdm_lookup("cpu1_pwrdm");
@@ -248,5 +328,5 @@ int __init omap4_idle_init(void)
        /* Configure the broadcast timer on each cpu */
        on_each_cpu(omap_setup_broadcast_timer, NULL, 1);

-       return cpuidle_register(&omap4_idle_driver, cpu_online_mask);
+       return cpuidle_register(idle_driver, cpu_online_mask);
  }
diff --git a/arch/arm/mach-omap2/pm44xx.c b/arch/arm/mach-omap2/pm44xx.c
index c063833..1d22162 100644
--- a/arch/arm/mach-omap2/pm44xx.c
+++ b/arch/arm/mach-omap2/pm44xx.c
@@ -293,7 +293,7 @@ int __init omap4_pm_init(void)
        /* Overwrite the default cpu_do_idle() */
        arm_pm_idle = omap_default_idle;

-       if (cpu_is_omap44xx())
+       if (cpu_is_omap44xx() || soc_is_dra7xx() || soc_is_omap54xx())
                omap4_idle_init();

  err2:



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