drivers: firmware: psci: add system suspend support

PSCI v1.0 introduces a new API called PSCI_SYSTEM_SUSPEND. This API
provides the mechanism by which the calling OS can request entry into
the deepest possible system sleep state.

It meets all the necessary preconditions for entering suspend to RAM
state in Linux. This patch adds support for PSCI_SYSTEM_SUSPEND in psci
firmware and registers a psci system suspend operation to implement the
suspend-to-RAM(s2r) in a generic way on all the platforms implementing
PSCI.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
(cherry picked from commit faf7ec4a92c0231d1079177095077c162eb9b466)
Signed-off-by: Alex Shi <alex.shi@linaro.org>

1 files changed, 33 insertions, 0 deletions

diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
index 662144d4a218..2b46b00e002e 100644
--- a/drivers/firmware/psci.c
+++ b/drivers/firmware/psci.c
@@ -20,12 +20,14 @@
 #include <linux/printk.h>
 #include <linux/psci.h>
 #include <linux/reboot.h>
+#include <linux/suspend.h>
 
 #include <uapi/linux/psci.h>
 
 #include <asm/cputype.h>
 #include <asm/system_misc.h>
 #include <asm/smp_plat.h>
+#include <asm/suspend.h>
 
 /*
  * While a 64-bit OS can make calls with SMC32 calling conventions, for some
@@ -223,6 +225,35 @@ static int __init psci_features(u32 psci_func_id)
 			      psci_func_id, 0, 0);
 }
 
+static int psci_system_suspend(unsigned long unused)
+{
+	return invoke_psci_fn(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND),
+			      virt_to_phys(cpu_resume), 0, 0);
+}
+
+static int psci_system_suspend_enter(suspend_state_t state)
+{
+	return cpu_suspend(0, psci_system_suspend);
+}
+
+static const struct platform_suspend_ops psci_suspend_ops = {
+	.valid          = suspend_valid_only_mem,
+	.enter          = psci_system_suspend_enter,
+};
+
+static void __init psci_init_system_suspend(void)
+{
+	int ret;
+
+	if (!IS_ENABLED(CONFIG_SUSPEND))
+		return;
+
+	ret = psci_features(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND));
+
+	if (ret != PSCI_RET_NOT_SUPPORTED)
+		suspend_set_ops(&psci_suspend_ops);
+}
+
 static void __init psci_init_cpu_suspend(void)
 {
 	int feature = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);
@@ -318,6 +349,8 @@ static int __init psci_probe(void)
 
 	psci_init_cpu_suspend();
 
+	psci_init_system_suspend();
+
 	return 0;
 }