On Wed, Mar 13, 2019 at 03:21:24PM -0700, Rajat Jain wrote:
> Add a module parameter which when enabled, will check on resume, if the
> last S0ix attempt was successful. If not, the driver would provide
> helpful debug information (which gets latched during the failed suspend
> attempt) to debug the S0ix failure.
+ Srinivas and David.
>
> This information is very useful to debug S0ix failures. Specially since
> the latched debug information will be lost (over-written) if the system
> attempts to go into runtime (or imminent) S0ix again after that failed
> suspend attempt.
>
> Signed-off-by: Rajat Jain <raja...@google.com>
> ---
> drivers/platform/x86/intel_pmc_core.c | 86 +++++++++++++++++++++++++++
> drivers/platform/x86/intel_pmc_core.h | 7 +++
> 2 files changed, 93 insertions(+)
>
> diff --git a/drivers/platform/x86/intel_pmc_core.c
> b/drivers/platform/x86/intel_pmc_core.c
> index 55578d07610c..b1f4405a27ce 100644
> --- a/drivers/platform/x86/intel_pmc_core.c
> +++ b/drivers/platform/x86/intel_pmc_core.c
> @@ -20,6 +20,7 @@
> #include <linux/module.h>
> #include <linux/pci.h>
> #include <linux/platform_device.h>
> +#include <linux/suspend.h>
> #include <linux/uaccess.h>
>
> #include <asm/cpu_device_id.h>
> @@ -890,9 +891,94 @@ static int pmc_core_remove(struct platform_device *pdev)
> return 0;
> }
>
> +#ifdef CONFIG_PM_SLEEP
> +
> +static bool warn_on_s0ix_failures;
> +module_param(warn_on_s0ix_failures, bool, 0644);
> +MODULE_PARM_DESC(warn_on_s0ix_failures, "Check and warn for S0ix failures");
> +
> +static int pmc_core_suspend(struct device *dev)
> +{
> + struct pmc_dev *pmcdev = dev_get_drvdata(dev);
> +
> + /* Save PC10 and S0ix residency for checking later */
> + if (warn_on_s0ix_failures &&
> + !rdmsrl_safe(MSR_PKG_C10_RESIDENCY, &pmcdev->pc10_counter) &&
> + !pmc_core_dev_state_get(pmcdev, &pmcdev->s0ix_counter))
> + pmcdev->check_counters = true;
> + else
> + pmcdev->check_counters = false;
> +
> + return 0;
> +}
> +
> +static inline bool pc10_failed(struct pmc_dev *pmcdev)
> +{
> + u64 pc10_counter;
> +
> + if (!rdmsrl_safe(MSR_PKG_C10_RESIDENCY, &pc10_counter) &&
> + pc10_counter == pmcdev->pc10_counter)
> + return true;
> + else
> + return false;
> +}
> +
> +static inline bool s0ix_failed(struct pmc_dev *pmcdev)
> +{
> + u64 s0ix_counter;
> +
> + if (!pmc_core_dev_state_get(pmcdev, &s0ix_counter) &&
> + s0ix_counter == pmcdev->s0ix_counter)
> + return true;
> + else
> + return false;
> +}
> +
> +static int pmc_core_resume(struct device *dev)
> +{
> + struct pmc_dev *pmcdev = dev_get_drvdata(dev);
> +
> + if (!pmcdev->check_counters)
> + return 0;
> +
> + if (pc10_failed(pmcdev)) {
> + dev_info(dev, "PC10 entry had failed (PC10 cnt=0x%llx)\n",
> + pmcdev->pc10_counter);
> + } else if (s0ix_failed(pmcdev)) {
> +
> + const struct pmc_bit_map **maps = pmcdev->map->slps0_dbg_maps;
slps0_dbg feature is not available on Skylake and Kabylake. PCH IP power
gating status is available on all.
> + const struct pmc_bit_map *map;
> + int offset = pmcdev->map->slps0_dbg_offset;
> + u32 data;
> +
> + dev_warn(dev, "S0ix entry had failed (S0ix cnt=%llu)\n",
> + pmcdev->s0ix_counter);
I feel this dev_warn may be frowned upon and should be possible kept behind
something like pm_debug_messages_on though module param helps mitigate it.
> + while (*maps) {
> + map = *maps;
> + data = pmc_core_reg_read(pmcdev, offset);
> + offset += 4;
> + while (map->name) {
> + dev_warn(dev, "SLP_S0_DBG: %-32s\tState: %s\n",
> + map->name,
> + data & map->bit_mask ? "Yes" : "No");
> + ++map;
> + }
> + ++maps;
> + }
> + }
> + return 0;
> +}
> +
> +#endif
> +
> +const struct dev_pm_ops pmc_core_pm_ops = {
> + SET_LATE_SYSTEM_SLEEP_PM_OPS(pmc_core_suspend, pmc_core_resume)
> +};
> +
> static struct platform_driver pmc_core_driver = {
> .driver = {
> .name = "pmc_core",
> + .pm = &pmc_core_pm_ops
> },
> .probe = pmc_core_probe,
> .remove = pmc_core_remove,
> diff --git a/drivers/platform/x86/intel_pmc_core.h
> b/drivers/platform/x86/intel_pmc_core.h
> index 88d9c0653a5f..fdee5772e532 100644
> --- a/drivers/platform/x86/intel_pmc_core.h
> +++ b/drivers/platform/x86/intel_pmc_core.h
> @@ -241,6 +241,9 @@ struct pmc_reg_map {
> * @pmc_xram_read_bit: flag to indicate whether PMC XRAM shadow
> registers
> * used to read MPHY PG and PLL status are available
> * @mutex_lock: mutex to complete one transcation
> + * @check_counters: On resume, check if counters are getting incremented
> + * @pc10_counter: PC10 residency counter
> + * @s0ix_counter: S0ix residency (step adjusted)
> *
> * pmc_dev contains info about power management controller device.
> */
> @@ -253,6 +256,10 @@ struct pmc_dev {
> #endif /* CONFIG_DEBUG_FS */
> int pmc_xram_read_bit;
> struct mutex lock; /* generic mutex lock for PMC Core */
> +
> + bool check_counters; /* Check for counter increments on resume */
> + u64 pc10_counter;
> + u64 s0ix_counter;
> };
>
> #endif /* PMC_CORE_H */
> --
> 2.21.0.360.g471c308f928-goog
>
--
Best Regards,
Rajneesh
