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.
Acked-by: Peter De Schrijver <pdeschrijver@xxxxxxxxxx>
Tested-by: Peter Geis <pgwipeout@xxxxxxxxx>
Tested-by: Jasper Korten <jja2000@xxxxxxxxx>
Tested-by: David Heidelberg <david@xxxxxxx>
Tested-by: Nicolas Chauvet <kwizart@xxxxxxxxx>
Acked-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
arch/arm/mach-tegra/cpuidle-tegra20.c | 51 +++++++++++++++++++++++++--
1 file changed, 49 insertions(+), 2 deletions(-)
diff --git a/arch/arm/mach-tegra/cpuidle-tegra20.c b/arch/arm/mach-tegra/cpuidle-tegra20.c
index a5b7d4e68f43..40566da25c6c 100644
--- a/arch/arm/mach-tegra/cpuidle-tegra20.c
+++ b/arch/arm/mach-tegra/cpuidle-tegra20.c
@@ -14,6 +14,7 @@
#include <linux/tick.h>
#include <linux/cpuidle.h>
#include <linux/cpu_pm.h>
+#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/module.h>
@@ -82,14 +83,60 @@ static inline void tegra20_wake_cpu1_from_reset(void)
}
#endif
+static void tegra20_report_cpus_state(void)
+{
+ unsigned long cpu, lcpu, csr;
+
+ for_each_cpu(lcpu, cpu_possible_mask) {
+ cpu = cpu_logical_map(lcpu);
+ csr = flowctrl_read_cpu_csr(cpu);
+
+ pr_err("cpu%lu: online=%d flowctrl_csr=0x%08lx\n",
+ cpu, cpu_online(lcpu), csr);
+ }
+}
+
+static int tegra20_wait_for_secondary_cpu_parking(void)
+{
+ unsigned int retries = 3;
+
+ while (retries--) {
+ unsigned int delay_us = 10;
+ unsigned int timeout_us = 500 * 1000 / delay_us;
+
+ /*
+ * 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;
+
+ udelay(delay_us);
+
+ } while (timeout_us--);
+
+ pr_err("secondary CPU taking too long to park\n");
+
+ 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
