It is possible that something may go wrong with the secondary CPU, in that
case it is much nicer to get a dump of the flow-controller state before
hanging machine.
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
arch/arm/mach-tegra/cpuidle-tegra20.c | 46 +++++++++++++++++++++++++--
1 file changed, 44 insertions(+), 2 deletions(-)
diff --git a/arch/arm/mach-tegra/cpuidle-tegra20.c b/arch/arm/mach-tegra/cpuidle-tegra20.c
index 9672c619f4bc..f3a898f69a1d 100644
--- a/arch/arm/mach-tegra/cpuidle-tegra20.c
+++ b/arch/arm/mach-tegra/cpuidle-tegra20.c
@@ -83,14 +83,56 @@ static inline void tegra20_wake_cpu1_from_reset(void)
}
#endif
+static void tegra20_report_cpus_state(void)
+{
+ unsigned int cpu, lcpu;
+
+ pr_err("secondary CPU taking too long to park\n");
+
+ for_each_cpu(lcpu, cpu_possible_mask) {
+ cpu = cpu_logical_map(lcpu);
+
+ pr_err("cpu%u: online=%d flowctrl_csr=0x%08x\n",
+ cpu, cpu_online(lcpu), flowctrl_read_cpu_csr(cpu));
+ }
+}
+
+static int tegra20_wait_for_secondary_cpu_parking(void)
+{
+ unsigned int retries = 3;
+
+ while (retries--) {
+ ktime_t timeout = ktime_add_ms(ktime_get(), 500);
+
+ /*
+ * The primary CPU0 core shall wait for the secondaries
+ * shutdown in order to power-off CPU's cluster safely.
+ * The timeout value depends on the current CPU frequency,
+ * it takes about 40-150us in average and over 1000us in
+ * a worst case scenario.
+ */
+ do {
+ if (tegra_cpu_rail_off_ready())
+ return 0;
+
+ } while (ktime_before(ktime_get(), timeout));
+
+ tegra20_report_cpus_state();
+ }
+
+ pr_err("timed out waiting secondaries to park\n");
+
+ return -ETIMEDOUT;
+}
+
static bool tegra20_cpu_cluster_power_down(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
bool ret;
- while (!tegra_cpu_rail_off_ready())
- cpu_relax();
+ if (tegra20_wait_for_secondary_cpu_parking())
+ return false;
ret = !tegra_pm_enter_lp2();
--
2.24.0
