[PATCH 2/2] ARM: vexpress/TC2: implement PM suspend method

[nicolas.pitre@linaro.org (Nicolas Pitre)]

From: Nicolas Pitre <nico@linaro.org>

This is simplistic for the moment as the expected residency is used to
prevent the shutting down of L2 and the cluster if the residency for
the last man is lower than 5 ms.  To make this right, the shutdown
latency for each CPU would need to be recorded and taken into account.

On a suspend, the firmware mailbox address has to be set prior entering
low power mode.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
---
 arch/arm/mach-vexpress/tc2_pm.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-vexpress/tc2_pm.c b/arch/arm/mach-vexpress/tc2_pm.c
index a3ea524372..7901528566 100644
--- a/arch/arm/mach-vexpress/tc2_pm.c
+++ b/arch/arm/mach-vexpress/tc2_pm.c
@@ -79,7 +79,7 @@ static int tc2_pm_power_up(unsigned int cpu, unsigned int cluster)
 	return 0;
 }
 
-static void tc2_pm_power_down(void)
+static void tc2_pm_down(u64 residency)
 {
 	unsigned int mpidr, cpu, cluster;
 	bool last_man = false, skip_wfi = false;
@@ -100,7 +100,8 @@ static void tc2_pm_power_down(void)
 		vexpress_spc_set_cpu_wakeup_irq(cpu, cluster, 1);
 		if (!tc2_pm_use_count[0][cluster] &&
 		    !tc2_pm_use_count[1][cluster] &&
-		    !tc2_pm_use_count[2][cluster]) {
+		    !tc2_pm_use_count[2][cluster] &&
+		    (!residency || residency > 5000)) {
 			vexpress_spc_powerdown_enable(cluster, 1);
 			vexpress_spc_set_global_wakeup_intr(1);
 			last_man = true;
@@ -161,6 +162,23 @@ static void tc2_pm_power_down(void)
 	/* Not dead at this point?  Let our caller cope. */
 }
 
+static void tc2_pm_power_down(void)
+{
+	tc2_pm_down(0);
+}
+
+static void tc2_pm_suspend(u64 residency)
+{
+	unsigned int mpidr, cpu, cluster;
+
+	mpidr = read_cpuid_mpidr();
+	cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
+	cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
+	vexpress_spc_write_resume_reg(cluster, cpu,
+				      virt_to_phys(mcpm_entry_point));
+	tc2_pm_down(residency);
+}
+
 static void tc2_pm_powered_up(void)
 {
 	unsigned int mpidr, cpu, cluster;
@@ -196,6 +214,7 @@ static void tc2_pm_powered_up(void)
 static const struct mcpm_platform_ops tc2_pm_power_ops = {
 	.power_up	= tc2_pm_power_up,
 	.power_down	= tc2_pm_power_down,
+	.suspend	= tc2_pm_suspend,
 	.powered_up	= tc2_pm_powered_up,
 };
 
-- 
1.8.1.2