OMAP3: PM: move device-specific special cases from PM core into CPUidle

In an effort to simplify the core idle path, move any device-specific
special case handling from the core PM idle path into the CPUidle
pre-idle checking path.

This keeps the core, interrupts-disabled idle path streamlined and
independent of any device-specific handling, and also allows CPUidle
to do the checking only for certain C-states as needed.  This patch
has the device checks in place for all states with the CHECK_BM flag,
namely all states >= C2.

This patch was inspired by a similar patch written by Tero Kristo as
part of a larger series to add INACTIVE state support.

NOTE: This is a baby-step towards decoupling device idle (or system
idle) from CPU idle.  Eventually, CPUidle should only manage the CPU,
and device/system idle should be managed elsewhere.

Cc: Tero Kristo <tero.kristo@nokia.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

2 files changed, 56 insertions, 16 deletions

diff --git a/arch/arm/mach-omap2/cpuidle34xx.c b/arch/arm/mach-omap2/cpuidle34xx.c
index 3d3d035db9a..8ea012ef0b5 100644
--- a/arch/arm/mach-omap2/cpuidle34xx.c
+++ b/arch/arm/mach-omap2/cpuidle34xx.c
@@ -60,7 +60,8 @@ struct omap3_processor_cx {
 
 struct omap3_processor_cx omap3_power_states[OMAP3_MAX_STATES];
 struct omap3_processor_cx current_cx_state;
-struct powerdomain *mpu_pd, *core_pd;
+struct powerdomain *mpu_pd, *core_pd, *per_pd;
+struct powerdomain *cam_pd;
 
 /*
  * The latencies/thresholds for various C states have
@@ -233,14 +234,62 @@ static int omap3_enter_idle_bm(struct cpuidle_device *dev,
                                struct cpuidle_state *state)
 {
         struct cpuidle_state *new_state = next_valid_state(dev, state);
+        u32 core_next_state, per_next_state = 0, per_saved_state = 0;
+        u32 cam_state;
+        struct omap3_processor_cx *cx;
+        int ret;
 
         if ((state->flags & CPUIDLE_FLAG_CHECK_BM) && omap3_idle_bm_check()) {
                 BUG_ON(!dev->safe_state);
                 new_state = dev->safe_state;
+                goto select_state;
+        }
+
+        cx = cpuidle_get_statedata(state);
+        core_next_state = cx->core_state;
+
+        /*
+         * FIXME: we currently manage device-specific idle states
+         *        for PER and CORE in combination with CPU-specific
+         *        idle states.  This is wrong, and device-specific
+         *        idle managment needs to be separated out into 
+         *        its own code.
+         */
+
+        /*
+         * Prevent idle completely if CAM is active.
+         * CAM does not have wakeup capability in OMAP3.
+         */
+        cam_state = pwrdm_read_pwrst(cam_pd);
+        if (cam_state == PWRDM_POWER_ON) {
+                new_state = dev->safe_state;
+                goto select_state;
+        }
+
+        /*
+         * Prevent PER off if CORE is not in retention or off as this
+         * would disable PER wakeups completely.
+         */
+        per_next_state = per_saved_state = pwrdm_read_next_pwrst(per_pd);
+        if ((per_next_state == PWRDM_POWER_OFF) &&
+            (core_next_state > PWRDM_POWER_RET)) {
+                per_next_state = PWRDM_POWER_RET;
+                pwrdm_set_next_pwrst(per_pd, per_next_state);
         }
 
+        /* Are we changing PER target state? */
+        if (per_next_state != per_saved_state)
+                pwrdm_set_next_pwrst(per_pd, per_next_state);
+
+select_state:
         dev->last_state = new_state;
-        return omap3_enter_idle(dev, new_state);
+        ret = omap3_enter_idle(dev, new_state);
+
+        /* Restore original PER state if it was modified */
+        if (per_next_state != per_saved_state)
+                pwrdm_set_next_pwrst(per_pd, per_saved_state);
+
+        return ret;
 }
 
 DEFINE_PER_CPU(struct cpuidle_device, omap3_idle_dev);
@@ -328,7 +377,8 @@ void omap_init_power_states(void)
                         cpuidle_params_table[OMAP3_STATE_C2].threshold;
         omap3_power_states[OMAP3_STATE_C2].mpu_state = PWRDM_POWER_ON;
         omap3_power_states[OMAP3_STATE_C2].core_state = PWRDM_POWER_ON;
-        omap3_power_states[OMAP3_STATE_C2].flags = CPUIDLE_FLAG_TIME_VALID;
+        omap3_power_states[OMAP3_STATE_C2].flags = CPUIDLE_FLAG_TIME_VALID |
+                                CPUIDLE_FLAG_CHECK_BM;
 
         /* C3 . MPU CSWR + Core inactive */
         omap3_power_states[OMAP3_STATE_C3].valid =
@@ -426,6 +476,8 @@ int __init omap3_idle_init(void)
 
         mpu_pd = pwrdm_lookup("mpu_pwrdm");
         core_pd = pwrdm_lookup("core_pwrdm");
+        per_pd = pwrdm_lookup("per_pwrdm");
+        cam_pd = pwrdm_lookup("cam_pwrdm");
 
         omap_init_power_states();
         cpuidle_register_driver(&omap3_idle_driver);
diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
index 429268eaf8b..bb2ba1e03d0 100644
--- a/arch/arm/mach-omap2/pm34xx.c
+++ b/arch/arm/mach-omap2/pm34xx.c
@@ -346,7 +346,6 @@ void omap_sram_idle(void)
         int core_next_state = PWRDM_POWER_ON;
         int core_prev_state, per_prev_state;
         u32 sdrc_pwr = 0;
-        int per_state_modified = 0;
 
         if (!_omap_sram_idle)
                 return;
@@ -391,19 +390,10 @@ void omap_sram_idle(void)
         if (per_next_state < PWRDM_POWER_ON) {
                 omap_uart_prepare_idle(2);
                 omap2_gpio_prepare_for_idle(per_next_state);
-                if (per_next_state == PWRDM_POWER_OFF) {
-                        if (core_next_state == PWRDM_POWER_ON) {
-                                per_next_state = PWRDM_POWER_RET;
-                                pwrdm_set_next_pwrst(per_pwrdm, per_next_state);
-                                per_state_modified = 1;
-                        } else
+                if (per_next_state == PWRDM_POWER_OFF)
                                 omap3_per_save_context();
-                }
         }
 
-        if (pwrdm_read_pwrst(cam_pwrdm) == PWRDM_POWER_ON)
-                omap2_clkdm_deny_idle(mpu_pwrdm->pwrdm_clkdms[0]);
-
         /* CORE */
         if (core_next_state < PWRDM_POWER_ON) {
                 omap_uart_prepare_idle(0);
@@ -470,8 +460,6 @@ void omap_sram_idle(void)
                 if (per_prev_state == PWRDM_POWER_OFF)
                         omap3_per_restore_context();
                 omap_uart_resume_idle(2);
-                if (per_state_modified)
-                        pwrdm_set_next_pwrst(per_pwrdm, PWRDM_POWER_OFF);
         }
 
         /* Disable IO-PAD and IO-CHAIN wakeup */