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Message-ID: <27751c8ff02d98cabd512472b29078b11f4bdf0e.camel@linux.intel.com>
Date: Sat, 24 Jul 2021 12:49:01 -0700
From: "David E. Box" <david.e.box@...ux.intel.com>
To: Andy Shevchenko <andy.shevchenko@...il.com>,
Michael Bottini <michael.a.bottini@...ux.intel.com>
Cc: "rjw@...ysocki.net" <rjw@...ysocki.net>,
"lenb@...nel.org" <lenb@...nel.org>,
"irenic.rajneesh@...il.com" <irenic.rajneesh@...il.com>,
"hdegoede@...hat.com" <hdegoede@...hat.com>,
"mgross@...ux.intel.com" <mgross@...ux.intel.com>,
"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"platform-driver-x86@...r.kernel.org"
<platform-driver-x86@...r.kernel.org>
Subject: Re: [PATCH 2/2] platform/x86/intel/pmc: Add PSON residency counter
On Sat, 2021-07-24 at 11:29 +0300, Andy Shevchenko wrote:
>
>
> On Friday, July 23, 2021, Michael Bottini
> <michael.a.bottini@...ux.intel.com> wrote:
> > Tiger Lake devices have the capability to track the duration
> > of time that their Power Supply Units (PSUs) are turned off during
> > S0ix.
> > This patch adds a debugfs file `pson_residency_usec` to provide
> > access to this counter.
> >
> > In order to determine whether the device is capable of PSON,
> > use acpi_init_properties() to reevaluate _DSD.
> >
> >
>
> It’s direct abuse of ACPI specification as I read it:
>
> “_DSD must return the same data each time it is evaluated. Firmware
> should not expect it to be evaluated every time (in case it is
> implemented as a method).”
>
>
> NAK to the series.
Okay, we'll check with the BIOS folks. They are setting this property
from _STA. They may not expect OSPM to reevaluate _DSD. But they may
have expected that OSPM doesn't attempt to read _DSD until after _STA
is executed.
David
>
>
>
>
>
> > Signed-off-by: Michael Bottini <michael.a.bottini@...ux.intel.com>
> > ---
> > drivers/platform/x86/intel/pmc/core.c | 46
> > +++++++++++++++++++++++++++
> > drivers/platform/x86/intel/pmc/core.h | 7 ++++
> > 2 files changed, 53 insertions(+)
> >
> > diff --git a/drivers/platform/x86/intel/pmc/core.c
> > b/drivers/platform/x86/intel/pmc/core.c
> > index 7c4bf7d22fd5..6cf06aecf368 100644
> > --- a/drivers/platform/x86/intel/pmc/core.c
> > +++ b/drivers/platform/x86/intel/pmc/core.c
> > @@ -595,6 +595,8 @@ static const struct pmc_reg_map tgl_reg_map = {
> > .lpm_sts = tgl_lpm_maps,
> > .lpm_status_offset = TGL_LPM_STATUS_OFFSET,
> > .lpm_live_status_offset = TGL_LPM_LIVE_STATUS_OFFSET,
> > + .pson_residency_offset = TGL_PSON_RESIDENCY_OFFSET,
> > + .pson_residency_counter_step = TGL_PSON_RES_COUNTER_STEP,
> > .etr3_offset = ETR3_OFFSET,
> > };
> >
> > @@ -1084,6 +1086,20 @@ static int pmc_core_dev_state_get(void
> > *data,
> > u64 *val)
> >
> > DEFINE_DEBUGFS_ATTRIBUTE(pmc_core_dev_state,
> > pmc_core_dev_state_get,
> > NULL, "%llu\n");
> >
> > +static int pmc_core_pson_residency_get(void *data, u64 *val)
> > +{
> > + struct pmc_dev *pmcdev = data;
> > + const struct pmc_reg_map *map = pmcdev->map;
> > + u32 value;
> > +
> > + value = pmc_core_reg_read(pmcdev, map-
> > > pson_residency_offset);
> > + *val = (u64)value * pmcdev->map-
> > >pson_residency_counter_step;
> > +
> > + return 0;
> > +}
> > +
> > +DEFINE_DEBUGFS_ATTRIBUTE(pmc_core_pson_residency,
> > pmc_core_pson_residency_get, NULL, "%llu\n");
> > +
> > static int pmc_core_check_read_lock_bit(struct pmc_dev *pmcdev)
> > {
> > u32 value;
> > @@ -1788,6 +1804,30 @@ static void
> > pmc_core_get_low_power_modes(struct pmc_dev *pmcdev)
> > }
> > }
> >
> > +static bool pmc_core_is_pson_residency_enabled(struct pmc_dev
> > *pmcdev)
> > +{
> > + struct platform_device *pdev = pmcdev->pdev;
> > + struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
> > + acpi_status status;
> > + u8 val;
> > +
> > + if (!adev)
> > + return false;
> > +
> > + acpi_init_properties(adev);
> > + status = acpi_evaluate_object(adev->handle, "PSOP", NULL,
> > NULL);
> > +
> > + if (ACPI_FAILURE(status))
> > + return false;
> > +
> > + if (fwnode_property_read_u8(acpi_fwnode_handle(adev),
> > + "intel-cec-pson-switching-
> > enabled-in-s0",
> > + &val))
> > + return false;
> > +
> > + return val == 1;
> > +}
> > +
> > static void pmc_core_dbgfs_unregister(struct pmc_dev *pmcdev)
> > {
> > debugfs_remove_recursive(pmcdev->dbgfs_dir);
> > @@ -1856,6 +1896,11 @@ static void pmc_core_dbgfs_register(struct
> > pmc_dev *pmcdev)
> > pmcdev->dbgfs_dir, pmcdev,
> >
> > &pmc_core_substate_req_regs_fops);
> > }
> > +
> > + if (pmcdev->map->pson_residency_offset &&
> > pmc_core_is_pson_residency_enabled(pmcdev)) {
> > + debugfs_create_file("pson_residency_usec", 0444,
> > + pmcdev->dbgfs_dir, pmcdev,
> > &pmc_core_pson_residency);
> > + }
> > }
> >
> > static const struct x86_cpu_id intel_pmc_core_ids[] = {
> > @@ -1944,6 +1989,7 @@ static int pmc_core_probe(struct
> > platform_device *pdev)
> > return -ENOMEM;
> >
> > platform_set_drvdata(pdev, pmcdev);
> > + pmcdev->pdev = pdev;
> >
> > cpu_id = x86_match_cpu(intel_pmc_core_ids);
> > if (!cpu_id)
> > diff --git a/drivers/platform/x86/intel/pmc/core.h
> > b/drivers/platform/x86/intel/pmc/core.h
> > index 333e25981e8e..822d77f49861 100644
> > --- a/drivers/platform/x86/intel/pmc/core.h
> > +++ b/drivers/platform/x86/intel/pmc/core.h
> > @@ -214,6 +214,10 @@ enum ppfear_regs {
> > #define TGL_LPM_PRI_OFFSET 0x1C7C
> > #define TGL_LPM_NUM_MAPS 6
> >
> > +/* Tigerlake PSON residency register */
> > +#define TGL_PSON_RESIDENCY_OFFSET 0x18f8
> > +#define TGL_PSON_RES_COUNTER_STEP 0x7A
> > +
> > /* Extended Test Mode Register 3 (CNL and later) */
> > #define ETR3_OFFSET 0x1048
> > #define ETR3_CF9GR BIT(20)
> > @@ -301,6 +305,8 @@ struct pmc_reg_map {
> > const u32 lpm_residency_offset;
> > const u32 lpm_status_offset;
> > const u32 lpm_live_status_offset;
> > + const u32 pson_residency_offset;
> > + const u32 pson_residency_counter_step;
> > const u32 etr3_offset;
> > };
> >
> > @@ -337,6 +343,7 @@ struct pmc_dev {
> > int num_lpm_modes;
> > int lpm_en_modes[LPM_MAX_NUM_MODES];
> > u32 *lpm_req_regs;
> > + struct platform_device *pdev;
> > };
> >
> > #define pmc_for_each_mode(i, mode, pmcdev) \
> > --
> > 2.25.1
> >
> >
>
>
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