Re: [PATCH V2 5/9] platform/x86: intel_pmc_core: Get LPM requirements for Tiger Lake
From: David E. Box
Date: Sat Apr 17 2021 - 21:43:55 EST
On Sat, 2021-04-17 at 11:00 +0200, Hans de Goede wrote:
> Hi,
>
> On 4/17/21 5:12 AM, David E. Box wrote:
> > From: Gayatri Kammela <gayatri.kammela@xxxxxxxxx>
> >
> > Platforms that support low power modes (LPM) such as Tiger Lake
> > maintain
> > requirements for each sub-state that a readable in the PMC.
> > However, unlike
> > LPM status registers, requirement registers are not memory mapped
> > but are
> > available from an ACPI _DSM. Collect the requirements for Tiger
> > Lake using
> > the _DSM method and store in a buffer.
> >
> > Signed-off-by: Gayatri Kammela <gayatri.kammela@xxxxxxxxx>
> > Co-developed-by: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
> > Signed-off-by: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
> > Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> > ---
> >
> > V2: - Move buffer allocation so that it does not need to be
> > freed
> > (which was missing anyway) when an error is encountered.
> > - Use label to free out_obj after errors
> > - Use memcpy instead of memcpy_fromio for ACPI memory
> >
> > drivers/platform/x86/intel_pmc_core.c | 56
> > +++++++++++++++++++++++++++
> > drivers/platform/x86/intel_pmc_core.h | 2 +
> > 2 files changed, 58 insertions(+)
> >
> > diff --git a/drivers/platform/x86/intel_pmc_core.c
> > b/drivers/platform/x86/intel_pmc_core.c
> > index 0e59a84b51bf..97efe9a6bd01 100644
> > --- a/drivers/platform/x86/intel_pmc_core.c
> > +++ b/drivers/platform/x86/intel_pmc_core.c
> > @@ -23,7 +23,9 @@
> > #include <linux/slab.h>
> > #include <linux/suspend.h>
> > #include <linux/uaccess.h>
> > +#include <linux/uuid.h>
> >
> > +#include <acpi/acpi_bus.h>
> > #include <asm/cpu_device_id.h>
> > #include <asm/intel-family.h>
> > #include <asm/msr.h>
> > @@ -31,6 +33,9 @@
> >
> > #include "intel_pmc_core.h"
> >
> > +#define ACPI_S0IX_DSM_UUID "57a6512e-3979-4e9d-9708-
> > ff13b2508972"
> > +#define ACPI_GET_LOW_MODE_REGISTERS 1
> > +
> > /* PKGC MSRs are common across Intel Core SoCs */
> > static const struct pmc_bit_map msr_map[] = {
> > {"Package C2", MSR_PKG_C2_RESIDENCY},
> > @@ -590,6 +595,53 @@ static const struct pmc_reg_map tgl_reg_map =
> > {
> > .etr3_offset = ETR3_OFFSET,
> > };
> >
> > +static void pmc_core_get_tgl_lpm_reqs(struct platform_device
> > *pdev)
> > +{
> > + struct pmc_dev *pmcdev = platform_get_drvdata(pdev);
> > + const int num_maps = pmcdev->map->lpm_num_maps;
> > + size_t lpm_size = LPM_MAX_NUM_MODES * num_maps * 4;
>
> The type of lpm_size should be an u32, so that it matches
> the type of out_obj->buffer.length.
>
> > + union acpi_object *out_obj;
> > + struct acpi_device *adev;
> > + guid_t s0ix_dsm_guid;
> > + u32 *lpm_req_regs, *addr;
> > +
> > + adev = ACPI_COMPANION(&pdev->dev);
> > + if (!adev)
> > + return;
> > +
> > + guid_parse(ACPI_S0IX_DSM_UUID, &s0ix_dsm_guid);
> > +
> > + out_obj = acpi_evaluate_dsm(adev->handle, &s0ix_dsm_guid,
> > 0,
> > + ACPI_GET_LOW_MODE_REGISTERS,
> > NULL);
> > + if (out_obj && out_obj->type == ACPI_TYPE_BUFFER) {
> > + int size = out_obj->buffer.length;
>
> out_obj->buffer.length is an u32, please make this an u32 too.
>
> > +
> > + if (size != lpm_size) {
> > + acpi_handle_debug(adev->handle,
> > + "_DSM returned unexpected buffer
> > size,"
> > + " have %d, expect %ld\n", size,
> > lpm_size);
>
> And use %u here (twice), this should also fix the warnings reported
> by the kernel test robot.
>
> If there are no objections against the suggested changes, then I can
> fix this up while merging this.
>
> Please let me know if the suggested changes are ok with you.
Changes are good with me. Thanks for the fixup.
David
>
> Regards,
>
> Hans
>
>
> > + goto free_acpi_obj;
> > + }
> > + } else {
> > + acpi_handle_debug(adev->handle,
> > + "_DSM function 0 evaluation
> > failed\n");
> > + goto free_acpi_obj;
> > + }
> > +
> > + addr = (u32 *)out_obj->buffer.pointer;
> > +
> > + lpm_req_regs = devm_kzalloc(&pdev->dev, lpm_size *
> > sizeof(u32),
> > + GFP_KERNEL);
> > + if (!lpm_req_regs)
> > + goto free_acpi_obj;
> > +
> > + memcpy(lpm_req_regs, addr, lpm_size);
> > + pmcdev->lpm_req_regs = lpm_req_regs;
> > +
> > +free_acpi_obj:
> > + ACPI_FREE(out_obj);
> > +}
> > +
> > static inline u32 pmc_core_reg_read(struct pmc_dev *pmcdev, int
> > reg_offset)
> > {
> > return readl(pmcdev->regbase + reg_offset);
> > @@ -1424,10 +1476,14 @@ static int pmc_core_probe(struct
> > platform_device *pdev)
> > return -ENOMEM;
> >
> > mutex_init(&pmcdev->lock);
> > +
> > pmcdev->pmc_xram_read_bit =
> > pmc_core_check_read_lock_bit(pmcdev);
> > pmc_core_get_low_power_modes(pmcdev);
> > pmc_core_do_dmi_quirks(pmcdev);
> >
> > + if (pmcdev->map == &tgl_reg_map)
> > + pmc_core_get_tgl_lpm_reqs(pdev);
> > +
> > /*
> > * On TGL, due to a hardware limitation, the GBE LTR blocks
> > PC10 when
> > * a cable is attached. Tell the PMC to ignore it.
> > diff --git a/drivers/platform/x86/intel_pmc_core.h
> > b/drivers/platform/x86/intel_pmc_core.h
> > index aa44fd5399cc..64fb368f40f6 100644
> > --- a/drivers/platform/x86/intel_pmc_core.h
> > +++ b/drivers/platform/x86/intel_pmc_core.h
> > @@ -294,6 +294,7 @@ struct pmc_reg_map {
> > * @s0ix_counter: S0ix residency (step adjusted)
> > * @num_lpm_modes: Count of enabled modes
> > * @lpm_en_modes: Array of enabled modes from lowest to
> > highest priority
> > + * @lpm_req_regs: List of substate requirements
> > *
> > * pmc_dev contains info about power management controller device.
> > */
> > @@ -310,6 +311,7 @@ struct pmc_dev {
> > u64 s0ix_counter;
> > int num_lpm_modes;
> > int lpm_en_modes[LPM_MAX_NUM_MODES];
> > + u32 *lpm_req_regs;
> > };
> >
> > #define pmc_for_each_mode(i, mode, pmcdev) \
> >
>