| From 19b0b30b590b3f5317e90be0c1aa881746c36186 Mon Sep 17 00:00:00 2001 |
| From: Eizan Miyamoto <eizan@chromium.org> |
| Date: Thu, 6 Aug 2020 15:34:04 +1000 |
| Subject: [PATCH] CHROMIUM: firmware/psci: Delay in psci_system_suspend |
| |
| Add a delay before calling PSCI SYSTEM_SUSPEND. This is a temporary hack |
| until we can get a fix into firmware. |
| |
| On MT8173, we have found that some of the other (non cpu-0) cores may |
| not have been powered down by the time that the SYSTEM_SUSPEND call is |
| made. When this happens, the device will hang when trying to enter S3 |
| suspend. |
| |
| The kernel disables non-boot CPUs by calling PSCI CPU_OFF, and then |
| polls the CPU status by calling PSCI AFFINITY_INFO. However, |
| AFFINITY_INFO only indicates the logical state of the CPU, and not the |
| full power off state as required to ensure a successful SYSTEM_SUSPEND |
| on MT8173. The delay has been inserted to give the hardware time to |
| fully reach power off state. |
| |
| The fix in firmware will poll the SPM_PWR_STATUS and SPM_PWR_STATUS_2ND |
| registers waiting for all the CPUs to go offline before going into |
| suspend. |
| |
| BUG=b:159288905, b:237033919 |
| TEST=stop_ui; suspend_stress_test -i spi32766 --noerrors_fatal |
| |
| Signed-off-by: Eizan Miyamoto <eizan@chromium.org> |
| Change-Id: I8fb733165fdb1a21562295b55f75ca76efeee442 |
| Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/2340938 |
| Reviewed-by: Daniel Kurtz <djkurtz@chromium.org> |
| Reviewed-by: Nicolas Boichat <drinkcat@chromium.org> |
| (cherry picked from commit 095e39dd03f7f279d51edab3b58c11deacde0c07) |
| Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3863207 |
| Commit-Queue: Pin-yen Lin <treapking@chromium.org> |
| Tested-by: Pin-yen Lin <treapking@chromium.org> |
| --- |
| drivers/firmware/psci/psci.c | 9 +++++++++ |
| 1 file changed, 9 insertions(+) |
| |
| diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c |
| index e7bcfca4159f603317660d8525e6eafd4488ec94..29c9ca321d8bae42b2b5994d741106cf6e612364 100644 |
| --- a/drivers/firmware/psci/psci.c |
| +++ b/drivers/firmware/psci/psci.c |
| @@ -10,6 +10,7 @@ |
| #include <linux/arm-smccc.h> |
| #include <linux/cpuidle.h> |
| #include <linux/debugfs.h> |
| +#include <linux/delay.h> |
| #include <linux/errno.h> |
| #include <linux/linkage.h> |
| #include <linux/of.h> |
| @@ -476,6 +477,14 @@ int psci_cpu_suspend_enter(u32 state) |
| static int psci_system_suspend(unsigned long unused) |
| { |
| phys_addr_t pa_cpu_resume = __pa_symbol(cpu_resume); |
| + /* |
| + * TODO(b/159288905): remove this sleep. It's a hack, specifically for |
| + * MT8173, giving CPUs time to be fully powered off before the PSCI call |
| + * for SYSTEM_SUSPEND is made. A real fix will be coming in the ARM |
| + * trusted firmware that waits for the cores to power down by reading |
| + * the SPM_PWR_STATUS[_2ND] registers inside the CPU_SUSPEND handler. |
| + */ |
| + mdelay(1); |
| |
| return invoke_psci_fn(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND), |
| pa_cpu_resume, 0, 0); |
| -- |
| 2.38.1.584.g0f3c55d4c2-goog |
| |
