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-rw-r--r--arch/arm/mach-vexpress/tc2_pm.c66
1 files changed, 61 insertions, 5 deletions
diff --git a/arch/arm/mach-vexpress/tc2_pm.c b/arch/arm/mach-vexpress/tc2_pm.c
index 05a364c5077..29e7785a54b 100644
--- a/arch/arm/mach-vexpress/tc2_pm.c
+++ b/arch/arm/mach-vexpress/tc2_pm.c
@@ -12,6 +12,7 @@
* published by the Free Software Foundation.
*/
+#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
@@ -32,11 +33,17 @@
#include "spc.h"
/* SCC conf registers */
+#define RESET_CTRL 0x018
+#define RESET_A15_NCORERESET(cpu) (1 << (2 + (cpu)))
+#define RESET_A7_NCORERESET(cpu) (1 << (16 + (cpu)))
+
#define A15_CONF 0x400
#define A7_CONF 0x500
#define SYS_INFO 0x700
#define SPC_BASE 0xb00
+static void __iomem *scc;
+
/*
* We can't use regular spinlocks. In the switcher case, it is possible
* for an outbound CPU to call power_down() after its inbound counterpart
@@ -190,6 +197,55 @@ static void tc2_pm_power_down(void)
tc2_pm_down(0);
}
+static int tc2_core_in_reset(unsigned int cpu, unsigned int cluster)
+{
+ u32 mask = cluster ?
+ RESET_A7_NCORERESET(cpu)
+ : RESET_A15_NCORERESET(cpu);
+
+ return !(readl_relaxed(scc + RESET_CTRL) & mask);
+}
+
+#define POLL_MSEC 10
+#define TIMEOUT_MSEC 1000
+
+static int tc2_pm_power_down_finish(unsigned int cpu, unsigned int cluster)
+{
+ unsigned tries;
+
+ pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+ BUG_ON(cluster >= TC2_CLUSTERS || cpu >= TC2_MAX_CPUS_PER_CLUSTER);
+
+ for (tries = 0; tries < TIMEOUT_MSEC / POLL_MSEC; ++tries) {
+ /*
+ * Only examine the hardware state if the target CPU has
+ * caught up at least as far as tc2_pm_down():
+ */
+ if (ACCESS_ONCE(tc2_pm_use_count[cpu][cluster]) == 0) {
+ pr_debug("%s(cpu=%u, cluster=%u): RESET_CTRL = 0x%08X\n",
+ __func__, cpu, cluster,
+ readl_relaxed(scc + RESET_CTRL));
+
+ /*
+ * We need the CPU to reach WFI, but the power
+ * controller may put the cluster in reset and
+ * power it off as soon as that happens, before
+ * we have a chance to see STANDBYWFI.
+ *
+ * So we need to check for both conditions:
+ */
+ if (tc2_core_in_reset(cpu, cluster) ||
+ ve_spc_cpu_in_wfi(cpu, cluster))
+ return 0; /* success: the CPU is halted */
+ }
+
+ /* Otherwise, wait and retry: */
+ msleep(POLL_MSEC);
+ }
+
+ return -ETIMEDOUT; /* timeout */
+}
+
static void tc2_pm_suspend(u64 residency)
{
unsigned int mpidr, cpu, cluster;
@@ -232,10 +288,11 @@ 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,
+ .power_up = tc2_pm_power_up,
+ .power_down = tc2_pm_power_down,
+ .power_down_finish = tc2_pm_power_down_finish,
+ .suspend = tc2_pm_suspend,
+ .powered_up = tc2_pm_powered_up,
};
static bool __init tc2_pm_usage_count_init(void)
@@ -269,7 +326,6 @@ static void __naked tc2_pm_power_up_setup(unsigned int affinity_level)
static int __init tc2_pm_init(void)
{
int ret, irq;
- void __iomem *scc;
u32 a15_cluster_id, a7_cluster_id, sys_info;
struct device_node *np;