ARM: EXYNOS: Add support for firmware-assisted suspend/resume

On a numer of Exynos-based boards Linux kernel is running in non-secure
mode under a secure firmware. This means that certain operations need to
be handled in special way, with firmware assistance. System-wide
suspend/resume is an example of such operations.

This patch adds support for firmware-assisted suspend/resume by
leveraging recently introduced suspend and resume firmware operations
and modifying existing suspend/resume paths to account for presence of
secure firmware.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
[kgene.kim@samsung.com: rebased]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

1 files changed, 45 insertions, 0 deletions

diff --git a/arch/arm/mach-exynos/firmware.c b/arch/arm/mach-exynos/firmware.c
index e8797bb78871..f5e626d55951 100644
--- a/arch/arm/mach-exynos/firmware.c
+++ b/arch/arm/mach-exynos/firmware.c
@@ -14,13 +14,20 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 
+#include <asm/cacheflush.h>
+#include <asm/cputype.h>
 #include <asm/firmware.h>
+#include <asm/suspend.h>
 
 #include <mach/map.h>
 
 #include "common.h"
 #include "smc.h"
 
+#define EXYNOS_SLEEP_MAGIC	0x00000bad
+#define EXYNOS_BOOT_ADDR	0x8
+#define EXYNOS_BOOT_FLAG	0xc
+
 static int exynos_do_idle(void)
 {
 	exynos_smc(SMC_CMD_SLEEP, 0, 0, 0);
@@ -69,10 +76,48 @@ static int exynos_set_cpu_boot_addr(int cpu, unsigned long boot_addr)
 	return 0;
 }
 
+static int exynos_cpu_suspend(unsigned long arg)
+{
+	flush_cache_all();
+	outer_flush_all();
+
+	exynos_smc(SMC_CMD_SLEEP, 0, 0, 0);
+
+	pr_info("Failed to suspend the system\n");
+	writel(0, sysram_ns_base_addr + EXYNOS_BOOT_FLAG);
+	return 1;
+}
+
+static int exynos_suspend(void)
+{
+	if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A9) {
+		/* Save Power control and Diagnostic registers */
+		asm ("mrc p15, 0, %0, c15, c0, 0\n"
+			"mrc p15, 0, %1, c15, c0, 1\n"
+			: "=r" (cp15_save_power), "=r" (cp15_save_diag)
+			: : "cc");
+	}
+
+	writel(EXYNOS_SLEEP_MAGIC, sysram_ns_base_addr + EXYNOS_BOOT_FLAG);
+	writel(virt_to_phys(exynos_cpu_resume_ns),
+		sysram_ns_base_addr + EXYNOS_BOOT_ADDR);
+
+	return cpu_suspend(0, exynos_cpu_suspend);
+}
+
+static int exynos_resume(void)
+{
+	writel(0, sysram_ns_base_addr + EXYNOS_BOOT_FLAG);
+
+	return 0;
+}
+
 static const struct firmware_ops exynos_firmware_ops = {
 	.do_idle		= exynos_do_idle,
 	.set_cpu_boot_addr	= exynos_set_cpu_boot_addr,
 	.cpu_boot		= exynos_cpu_boot,
+	.suspend		= exynos_suspend,
+	.resume			= exynos_resume,
 };
 
 void __init exynos_firmware_init(void)