From 51da5f1cd83444024db3f1d96eccf269e25a46bc Mon Sep 17 00:00:00 2001 From: Dmitry Osipenko Date: Tue, 25 Feb 2020 01:40:49 +0300 Subject: ARM: tegra: cpuidle: Handle case where secondary CPU hangs on entering LP2 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 Tested-by: Peter Geis Tested-by: Jasper Korten Tested-by: David Heidelberg Tested-by: Nicolas Chauvet Acked-by: Daniel Lezcano Signed-off-by: Dmitry Osipenko Signed-off-by: Thierry Reding --- arch/arm/mach-tegra/cpuidle-tegra20.c | 51 +++++++++++++++++++++++++++++++++-- 1 file changed, 49 insertions(+), 2 deletions(-) (limited to 'arch/arm/mach-tegra') diff --git a/arch/arm/mach-tegra/cpuidle-tegra20.c b/arch/arm/mach-tegra/cpuidle-tegra20.c index 3b61dd97bf3b..d6b9b4cf2635 100644 --- a/arch/arm/mach-tegra/cpuidle-tegra20.c +++ b/arch/arm/mach-tegra/cpuidle-tegra20.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include @@ -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(); -- cgit v1.2.3-59-g8ed1b