ARM: OMAP4: suspend: Add MPUSS power domain RETENTION support

This patch adds MPUSS(MPU Sub System) power domain
CSWR(Close Switch Retention) support to system wide suspend.
For MPUSS power domain to hit retention(CSWR or OSWR), both
CPU0 and CPU1 power domains need to be in OFF or DORMANT state,
since CPU power domain CSWR is not supported by hardware

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Vishwanath BS <vishwanath.bs@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

arch/arm/mach-omap2/omap-mpuss-lowpower.c

@@ -66,6 +66,7 @@ struct omap4_cpu_pm_info {
 };
 
 static DEFINE_PER_CPU(struct omap4_cpu_pm_info, omap4_pm_info);
+static struct powerdomain *mpuss_pd;
 
 /*
  * Program the wakeup routine address for the CPU0 and CPU1
@@ -140,6 +141,13 @@ static void scu_pwrst_prepare(unsigned int cpu_id, unsigned int cpu_state)
  * of OMAP4 MPUSS subsystem
  * @cpu : CPU ID
  * @power_state: Low power state.
+ *
+ * MPUSS states for the context save:
+ * save_state =
+ *	0 - Nothing lost and no need to save: MPUSS INACTIVE
+ *	1 - CPUx L1 and logic lost: MPUSS CSWR
+ *	2 - CPUx L1 and logic lost + GIC lost: MPUSS OSWR
+ *	3 - CPUx L1 and logic lost + GIC + L2 lost: DEVICE OFF
  */
 int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state)
 {
@@ -169,6 +177,7 @@ int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state)
 		return -ENXIO;
 	}
 
+	pwrdm_clear_all_prev_pwrst(mpuss_pd);
 	clear_cpu_prev_pwrst(cpu);
 	set_cpu_next_pwrst(cpu, power_state);
 	set_cpu_wakeup_addr(cpu, virt_to_phys(omap4_cpu_resume));
@@ -268,6 +277,13 @@ int __init omap4_mpuss_init(void)
 	/* Initialise CPU1 power domain state to ON */
 	pwrdm_set_next_pwrst(pm_info->pwrdm, PWRDM_POWER_ON);
 
+	mpuss_pd = pwrdm_lookup("mpu_pwrdm");
+	if (!mpuss_pd) {
+		pr_err("Failed to lookup MPUSS power domain\n");
+		return -ENODEV;
+	}
+	pwrdm_clear_all_prev_pwrst(mpuss_pd);
+
 	/* Save device type on scratchpad for low level code to use */
 	if (omap_type() != OMAP2_DEVICE_TYPE_GP)
 		__raw_writel(1, sar_base + OMAP_TYPE_OFFSET);

arch/arm/mach-omap2/pm44xx.c

@@ -1,8 +1,9 @@
 /*
  * OMAP4 Power Management Routines
  *
- * Copyright (C) 2010 Texas Instruments, Inc.
+ * Copyright (C) 2010-2011 Texas Instruments, Inc.
  * Rajendra Nayak <rnayak@ti.com>
+ * Santosh Shilimkar <santosh.shilimkar@ti.com>
  *
  * 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
@@ -19,6 +20,7 @@
 #include "common.h"
 #include "clockdomain.h"
 #include "powerdomain.h"
+#include "pm.h"
 
 struct power_state {
 	struct powerdomain *pwrdm;
@@ -34,7 +36,47 @@ static LIST_HEAD(pwrst_list);
 #ifdef CONFIG_SUSPEND
 static int omap4_pm_suspend(void)
 {
-	do_wfi();
+	struct power_state *pwrst;
+	int state, ret = 0;
+	u32 cpu_id = smp_processor_id();
+
+	/* Save current powerdomain state */
+	list_for_each_entry(pwrst, &pwrst_list, node) {
+		pwrst->saved_state = pwrdm_read_next_pwrst(pwrst->pwrdm);
+	}
+
+	/* Set targeted power domain states by suspend */
+	list_for_each_entry(pwrst, &pwrst_list, node) {
+		omap_set_pwrdm_state(pwrst->pwrdm, pwrst->next_state);
+	}
+
+	/*
+	 * For MPUSS to hit power domain retention(CSWR or OSWR),
+	 * CPU0 and CPU1 power domains need to be in OFF or DORMANT state,
+	 * since CPU power domain CSWR is not supported by hardware
+	 * Only master CPU follows suspend path. All other CPUs follow
+	 * CPU hotplug path in system wide suspend. On OMAP4, CPU power
+	 * domain CSWR is not supported by hardware.
+	 * More details can be found in OMAP4430 TRM section 4.3.4.2.
+	 */
+	omap4_enter_lowpower(cpu_id, PWRDM_POWER_OFF);
+
+	/* Restore next powerdomain state */
+	list_for_each_entry(pwrst, &pwrst_list, node) {
+		state = pwrdm_read_prev_pwrst(pwrst->pwrdm);
+		if (state > pwrst->next_state) {
+			pr_info("Powerdomain (%s) didn't enter "
+			       "target state %d\n",
+			       pwrst->pwrdm->name, pwrst->next_state);
+			ret = -1;
+		}
+		omap_set_pwrdm_state(pwrst->pwrdm, pwrst->saved_state);
+	}
+	if (ret)
+		pr_crit("Could not enter target state in pm_suspend\n");
+	else
+		pr_info("Successfully put all powerdomains to target state\n");
+
 	return 0;
 }
 
@@ -97,14 +139,30 @@ static int __init pwrdms_setup(struct powerdomain *pwrdm, void *unused)
 	if (!pwrdm->pwrsts)
 		return 0;
 
+	/*
+	 * Skip CPU0 and CPU1 power domains. CPU1 is programmed
+	 * through hotplug path and CPU0 explicitly programmed
+	 * further down in the code path
+	 */
+	if (!strncmp(pwrdm->name, "cpu", 3))
+		return 0;
+
+	/*
+	 * FIXME: Remove this check when core retention is supported
+	 * Only MPUSS power domain is added in the list.
+	 */
+	if (strcmp(pwrdm->name, "mpu_pwrdm"))
+		return 0;
+
 	pwrst = kmalloc(sizeof(struct power_state), GFP_ATOMIC);
 	if (!pwrst)
 		return -ENOMEM;
+
 	pwrst->pwrdm = pwrdm;
-	pwrst->next_state = PWRDM_POWER_ON;
+	pwrst->next_state = PWRDM_POWER_RET;
 	list_add(&pwrst->node, &pwrst_list);
 
-	return pwrdm_set_next_pwrst(pwrst->pwrdm, pwrst->next_state);
+	return omap_set_pwrdm_state(pwrst->pwrdm, pwrst->next_state);
 }
 
 /**