ARM: EXYNOS: Use MCPM call-backs to support S2R on exynos5420

Use the MCPM layer to handle core suspend/resume on Exynos5420.
Also, restore the entry address setup code post-resume.

Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

3 files changed, 78 insertions, 15 deletions

diff --git a/arch/arm/mach-exynos/mcpm-exynos.c b/arch/arm/mach-exynos/mcpm-exynos.c
index dc9a764a7c37..b0d3c2e876fb 100644
--- a/arch/arm/mach-exynos/mcpm-exynos.c
+++ b/arch/arm/mach-exynos/mcpm-exynos.c
@@ -15,6 +15,7 @@
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/of_address.h>
+#include <linux/syscore_ops.h>
 
 #include <asm/cputype.h>
 #include <asm/cp15.h>
@@ -30,6 +31,8 @@
 #define EXYNOS5420_USE_ARM_CORE_DOWN_STATE      BIT(29)
 #define EXYNOS5420_USE_L2_COMMON_UP_STATE       BIT(30)
 
+static void __iomem *ns_sram_base_addr;
+
 /*
  * The common v7_exit_coherency_flush API could not be used because of the
  * Erratum 799270 workaround. This macro is the same as the common one (in
@@ -318,10 +321,26 @@ static const struct of_device_id exynos_dt_mcpm_match[] = {
         {},
 };
 
+static void exynos_mcpm_setup_entry_point(void)
+{
+        /*
+         * U-Boot SPL is hardcoded to jump to the start of ns_sram_base_addr
+         * as part of secondary_cpu_start().  Let's redirect it to the
+         * mcpm_entry_point(). This is done during both secondary boot-up as
+         * well as system resume.
+         */
+        __raw_writel(0xe59f0000, ns_sram_base_addr);     /* ldr r0, [pc, #0] */
+        __raw_writel(0xe12fff10, ns_sram_base_addr + 4); /* bx  r0 */
+        __raw_writel(virt_to_phys(mcpm_entry_point), ns_sram_base_addr + 8);
+}
+
+static struct syscore_ops exynos_mcpm_syscore_ops = {
+        .resume = exynos_mcpm_setup_entry_point,
+};
+
 static int __init exynos_mcpm_init(void)
 {
         struct device_node *node;
-        void __iomem *ns_sram_base_addr;
         unsigned int value, i;
         int ret;
 
@@ -387,16 +406,9 @@ static int __init exynos_mcpm_init(void)
                 pmu_raw_writel(value, EXYNOS_COMMON_OPTION(i));
         }
 
-        /*
-         * U-Boot SPL is hardcoded to jump to the start of ns_sram_base_addr
-         * as part of secondary_cpu_start().  Let's redirect it to the
-         * mcpm_entry_point().
-         */
-        __raw_writel(0xe59f0000, ns_sram_base_addr);     /* ldr r0, [pc, #0] */
-        __raw_writel(0xe12fff10, ns_sram_base_addr + 4); /* bx  r0 */
-        __raw_writel(virt_to_phys(mcpm_entry_point), ns_sram_base_addr + 8);
+        exynos_mcpm_setup_entry_point();
 
-        iounmap(ns_sram_base_addr);
+        register_syscore_ops(&exynos_mcpm_syscore_ops);
 
         return ret;
 }
diff --git a/arch/arm/mach-exynos/platsmp.c b/arch/arm/mach-exynos/platsmp.c
index adb36a8e8785..7a1ebfeeeeb8 100644
--- a/arch/arm/mach-exynos/platsmp.c
+++ b/arch/arm/mach-exynos/platsmp.c
@@ -126,6 +126,18 @@ static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
  */
 void exynos_cpu_power_down(int cpu)
 {
+        if (cpu == 0 && (of_machine_is_compatible("samsung,exynos5420") ||
+                of_machine_is_compatible("samsung,exynos5800"))) {
+                /*
+                 * Bypass power down for CPU0 during suspend. Check for
+                 * the SYS_PWR_REG value to decide if we are suspending
+                 * the system.
+                 */
+                int val = pmu_raw_readl(EXYNOS5_ARM_CORE0_SYS_PWR_REG);
+
+                if (!(val & S5P_CORE_LOCAL_PWR_EN))
+                        return;
+        }
         pmu_raw_writel(0, EXYNOS_ARM_CORE_CONFIGURATION(cpu));
 }
 
diff --git a/arch/arm/mach-exynos/suspend.c b/arch/arm/mach-exynos/suspend.c
index 8cef6141c408..cc8d2374f1b1 100644
--- a/arch/arm/mach-exynos/suspend.c
+++ b/arch/arm/mach-exynos/suspend.c
@@ -24,6 +24,7 @@
 #include <asm/cacheflush.h>
 #include <asm/hardware/cache-l2x0.h>
 #include <asm/firmware.h>
+#include <asm/mcpm.h>
 #include <asm/smp_scu.h>
 #include <asm/suspend.h>
 
@@ -72,6 +73,7 @@ struct exynos_pm_data {
         unsigned int *release_ret_regs;
 
         void (*pm_prepare)(void);
+        void (*pm_resume_prepare)(void);
         void (*pm_resume)(void);
         int (*pm_suspend)(void);
         int (*cpu_suspend)(unsigned long);
@@ -172,9 +174,28 @@ static int exynos_cpu_suspend(unsigned long arg)
 
 static int exynos5420_cpu_suspend(unsigned long arg)
 {
-        exynos_flush_cache_all();
+        /* MCPM works with HW CPU identifiers */
+        unsigned int mpidr = read_cpuid_mpidr();
+        unsigned int cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
+        unsigned int cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
+
         __raw_writel(0x0, sysram_base_addr + EXYNOS5420_CPU_STATE);
-        return exynos_cpu_do_idle();
+
+        if (IS_ENABLED(CONFIG_EXYNOS5420_MCPM)) {
+                mcpm_set_entry_vector(cpu, cluster, exynos_cpu_resume);
+
+                /*
+                 * Residency value passed to mcpm_cpu_suspend back-end
+                 * has to be given clear semantics. Set to 0 as a
+                 * temporary value.
+                 */
+                mcpm_cpu_suspend(0);
+        }
+
+        pr_info("Failed to suspend the system\n");
+
+        /* return value != 0 means failure */
+        return 1;
 }
 
 static void exynos_pm_set_wakeup_mask(void)
@@ -189,9 +210,6 @@ static void exynos_pm_enter_sleep_mode(void)
         /* Set value of power down register for sleep mode */
         exynos_sys_powerdown_conf(SYS_SLEEP);
         pmu_raw_writel(S5P_CHECK_SLEEP, S5P_INFORM1);
-
-        /* ensure at least INFORM0 has the resume address */
-        pmu_raw_writel(virt_to_phys(exynos_cpu_resume), S5P_INFORM0);
 }
 
 static void exynos_pm_prepare(void)
@@ -206,6 +224,9 @@ static void exynos_pm_prepare(void)
                                 pm_data->num_extra_save);
 
         exynos_pm_enter_sleep_mode();
+
+        /* ensure at least INFORM0 has the resume address */
+        pmu_raw_writel(virt_to_phys(exynos_cpu_resume), S5P_INFORM0);
 }
 
 static void exynos5420_pm_prepare(void)
@@ -230,6 +251,10 @@ static void exynos5420_pm_prepare(void)
 
         exynos_pm_enter_sleep_mode();
 
+        /* ensure at least INFORM0 has the resume address */
+        if (IS_ENABLED(CONFIG_EXYNOS5420_MCPM))
+                pmu_raw_writel(virt_to_phys(mcpm_entry_point), S5P_INFORM0);
+
         tmp = pmu_raw_readl(EXYNOS5_ARM_L2_OPTION);
         tmp &= ~EXYNOS5_USE_RETENTION;
         pmu_raw_writel(tmp, EXYNOS5_ARM_L2_OPTION);
@@ -318,10 +343,21 @@ early_wakeup:
         pmu_raw_writel(0x0, S5P_INFORM1);
 }
 
+static void exynos5420_prepare_pm_resume(void)
+{
+        if (IS_ENABLED(CONFIG_EXYNOS5420_MCPM))
+                WARN_ON(mcpm_cpu_powered_up());
+}
+
 static void exynos5420_pm_resume(void)
 {
         unsigned long tmp;
 
+        /* Restore the CPU0 low power state register */
+        tmp = pmu_raw_readl(EXYNOS5_ARM_CORE0_SYS_PWR_REG);
+        pmu_raw_writel(tmp | S5P_CORE_LOCAL_PWR_EN,
+                EXYNOS5_ARM_CORE0_SYS_PWR_REG);
+
         /* Restore the sysram cpu state register */
         __raw_writel(exynos5420_cpu_state,
                 sysram_base_addr + EXYNOS5420_CPU_STATE);
@@ -391,6 +427,8 @@ static int exynos_suspend_enter(suspend_state_t state)
         if (ret)
                 return ret;
 
+        if (pm_data->pm_resume_prepare)
+                pm_data->pm_resume_prepare();
         s3c_pm_restore_uarts();
 
         S3C_PMDBG("%s: wakeup stat: %08x\n", __func__,
@@ -448,6 +486,7 @@ static struct exynos_pm_data exynos5420_pm_data = {
         .wkup_irq       = exynos5250_wkup_irq,
         .wake_disable_mask = (0x7F << 7) | (0x1F << 1),
         .release_ret_regs = exynos5420_release_ret_regs,
+        .pm_resume_prepare = exynos5420_prepare_pm_resume,
         .pm_resume      = exynos5420_pm_resume,
         .pm_suspend     = exynos5420_pm_suspend,
         .pm_prepare     = exynos5420_pm_prepare,