Re: [PATCH V2 5/9] platform/x86: intel_pmc_core: Get LPM requirements for Tiger Lake

Hans de Goede
2021-04-17T08:52:53Z

Hi David,

On 4/17/21 5:12 AM, David E. Box wrote:
> From: Gayatri Kammela <gayatri.kammela@intel.com>
>
> 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@intel.com>
> Co-developed-by: David E. Box <david.e.box@linux.intel.com>
> Signed-off-by: David E. Box <david.e.box@linux.intel.com>
> Reviewed-by: Hans de Goede <hdegoede@redhat.com>

Erm, I did not give my "Reviewed-by: Hans de Goede <hdegoede@redhat.com>"
for this patch, because it still needed some work.

Next time please only add my Reviewed-by to patches where I
explicitly replied with a Reviewed-by.

The same goes for patch 7/9

Regards,

Hans

> ---
>
> 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;
> + 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;
> +
> + if (size != lpm_size) {
> + acpi_handle_debug(adev->handle,
> + "_DSM returned unexpected buffer size,"
> + " have %d, expect %ld\n", size, lpm_size);
> + 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) \
>