From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: [PATCH v9 09/17] arm: tegra20: cpuidle: Handle case where secondary CPU hangs on entering LP2 Date: Thu, 13 Feb 2020 02:51:26 +0300 Message-ID: <20200212235134.12638-10-digetx@gmail.com> References: <20200212235134.12638-1-digetx@gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200212235134.12638-1-digetx@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Thierry Reding , Jonathan Hunter , Peter De Schrijver , "Rafael J. Wysocki" , Daniel Lezcano , =?UTF-8?q?Micha=C5=82=20Miros=C5=82aw?= , Jasper Korten , David Heidelberg , Peter Geis Cc: linux-pm@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-tegra@vger.kernel.org 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 Signed-off-by: Dmitry Osipenko --- arch/arm/mach-tegra/cpuidle-tegra20.c | 47 +++++++++++++++++++++++++-- 1 file changed, 45 insertions(+), 2 deletions(-) diff --git a/arch/arm/mach-tegra/cpuidle-tegra20.c b/arch/arm/mach-tegra/cpuidle-tegra20.c index 9672c619f4bc..bcc158b72e67 100644 --- a/arch/arm/mach-tegra/cpuidle-tegra20.c +++ b/arch/arm/mach-tegra/cpuidle-tegra20.c @@ -83,14 +83,57 @@ 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--) { + 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)); + + 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