Re: [PATCH V4 14/17] platform/x86/intel/pmc: Retrieve LPM information using Intel PMT

Ilpo Järvinen
2023-10-23T16:20:18Z

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On Wed, 18 Oct 2023, David E. Box wrote:

> From: Xi Pardee <xi.pardee@intel.com>
>
> On supported platforms, the low power mode (LPM) requirements for entering
> each idle substate are described in Platform Monitoring Technology (PMT)
> telemetry entries. Provide a function for platform code to attempt to find
> and read the requirements from the telemetry entries.
>
> Signed-off-by: Xi Pardee <xi.pardee@intel.com>
> Signed-off-by: David E. Box <david.e.box@linux.intel.com>
> ---
> V4 - no change
>
> V3 - no change
>
> V2 - remove extra parens
>
> drivers/platform/x86/intel/pmc/core.h | 3 +
> drivers/platform/x86/intel/pmc/core_ssram.c | 135 ++++++++++++++++++++
> 2 files changed, 138 insertions(+)
>
> diff --git a/drivers/platform/x86/intel/pmc/core.h b/drivers/platform/x86/intel/pmc/core.h
> index edaa70067e41..85b6f6ae4995 100644
> --- a/drivers/platform/x86/intel/pmc/core.h
> +++ b/drivers/platform/x86/intel/pmc/core.h
> @@ -320,6 +320,7 @@ struct pmc_reg_map {
> const u32 lpm_status_offset;
> const u32 lpm_live_status_offset;
> const u32 etr3_offset;
> + const u8 *lpm_reg_index;
> };
>
> /**
> @@ -329,6 +330,7 @@ struct pmc_reg_map {
> * specific attributes
> */
> struct pmc_info {
> + u32 guid;
> u16 devid;
> const struct pmc_reg_map *map;
> };
> @@ -486,6 +488,7 @@ extern const struct pmc_bit_map *mtl_ioem_lpm_maps[];
> extern const struct pmc_reg_map mtl_ioem_reg_map;
>
> extern void pmc_core_get_tgl_lpm_reqs(struct platform_device *pdev);
> +extern int pmc_core_ssram_get_lpm_reqs(struct pmc_dev *pmcdev);
> extern int pmc_core_send_ltr_ignore(struct pmc_dev *pmcdev, u32 value);
>
> int pmc_core_resume_common(struct pmc_dev *pmcdev);
> diff --git a/drivers/platform/x86/intel/pmc/core_ssram.c b/drivers/platform/x86/intel/pmc/core_ssram.c
> index 936aa0d5f452..f007964156bc 100644
> --- a/drivers/platform/x86/intel/pmc/core_ssram.c
> +++ b/drivers/platform/x86/intel/pmc/core_ssram.c
> @@ -24,6 +24,140 @@
> #define SSRAM_IOE_OFFSET 0x68
> #define SSRAM_DEVID_OFFSET 0x70
>
> +/* PCH query */
> +#define LPM_HEADER_OFFSET 1
> +#define LPM_REG_COUNT 28
> +#define LPM_MODE_OFFSET 1
> +
> +static u32 pmc_core_find_guid(struct pmc_info *list, const struct pmc_reg_map *map)
> +{
> + for (; list->map; ++list)
> + if (list->map == map)
> + return list->guid;
> +
> + return 0;
> +}
> +
> +static int pmc_core_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc)
> +{
> + struct telem_endpoint *ep;
> + const u8 *lpm_indices;
> + int num_maps, mode_offset = 0;
> + int ret, mode, i;
> + int lpm_size;
> + u32 guid;
> +
> + lpm_indices = pmc->map->lpm_reg_index;
> + num_maps = pmc->map->lpm_num_maps;
> + lpm_size = LPM_MAX_NUM_MODES * num_maps;
> +
> + guid = pmc_core_find_guid(pmcdev->regmap_list, pmc->map);
> + if (!guid)
> + return -ENXIO;
> +
> + ep = pmt_telem_find_and_register_endpoint(pmcdev->ssram_pcidev, guid, 0);
> + if (IS_ERR(ep)) {
> + dev_dbg(&pmcdev->pdev->dev, "couldn't get telem endpoint %ld",
> + PTR_ERR(ep));
> + return -EPROBE_DEFER;
> + }
> +
> + pmc->lpm_req_regs = devm_kzalloc(&pmcdev->pdev->dev,
> + lpm_size * sizeof(u32),
> + GFP_KERNEL);
> + if (!pmc->lpm_req_regs) {
> + ret = -ENOMEM;
> + goto unregister_ep;
> + }
> +
> + /*
> + * PMC Low Power Mode (LPM) table
> + *
> + * In telemetry space, the LPM table contains a 4 byte header followed
> + * by 8 consecutive mode blocks (one for each LPM mode). Each block
> + * has a 4 byte header followed by a set of registers that describe the
> + * IP state requirements for the given mode. The IP mapping is platform
> + * specific but the same for each block, making for easy analysis.
> + * Platforms only use a subset of the space to track the requirements
> + * for their IPs. Callers provide the requirement registers they use as
> + * a list of indices. Each requirement register is associated with an
> + * IP map that's maintained by the caller.
> + *
> + * Header
> + * +----+----------------------------+----------------------------+
> + * | 0 | REVISION | ENABLED MODES |
> + * +----+--------------+-------------+-------------+--------------+
> + *
> + * Low Power Mode 0 Block
> + * +----+--------------+-------------+-------------+--------------+
> + * | 1 | SUB ID | SIZE | MAJOR | MINOR |
> + * +----+--------------+-------------+-------------+--------------+
> + * | 2 | LPM0 Requirements 0 |
> + * +----+---------------------------------------------------------+
> + * | | ... |
> + * +----+---------------------------------------------------------+
> + * | 29 | LPM0 Requirements 27 |
> + * +----+---------------------------------------------------------+
> + *
> + * ...
> + *
> + * Low Power Mode 7 Block
> + * +----+--------------+-------------+-------------+--------------+
> + * | | SUB ID | SIZE | MAJOR | MINOR |
> + * +----+--------------+-------------+-------------+--------------+
> + * | 60 | LPM7 Requirements 0 |
> + * +----+---------------------------------------------------------+
> + * | | ... |
> + * +----+---------------------------------------------------------+
> + * | 87 | LPM7 Requirements 27 |
> + * +----+---------------------------------------------------------+
> + *
> + */
> + mode_offset = LPM_HEADER_OFFSET + LPM_MODE_OFFSET;
> + pmc_for_each_mode(i, mode, pmcdev) {
> + u32 *req_offset = pmc->lpm_req_regs + (mode * num_maps);
> + int m;
> +
> + for (m = 0; m < num_maps; m++) {
> + u8 sample_id = lpm_indices[m] + mode_offset;
> +
> + ret = pmt_telem_read32(ep, sample_id, req_offset, 1);
> + if (ret) {
> + dev_err(&pmcdev->pdev->dev,
> + "couldn't read Low Power Mode requirements: %d\n", ret);
> + devm_kfree(&pmcdev->pdev->dev, pmc->lpm_req_regs);
> + goto unregister_ep;
> + }
> + ++req_offset;
> + }
> + mode_offset += LPM_REG_COUNT + LPM_MODE_OFFSET;
> + }
> +
> +unregister_ep:
> + pmt_telem_unregister_endpoint(ep);
> +
> + return ret;
> +}
> +
> +int pmc_core_ssram_get_lpm_reqs(struct pmc_dev *pmcdev)
> +{
> + int ret, i;
> +
> + if (!pmcdev->ssram_pcidev)
> + return -ENODEV;
> +
> + for (i = 0; i < ARRAY_SIZE(pmcdev->pmcs); ++i) {
> + if (!pmcdev->pmcs[i])
> + continue;
> +
> + ret = pmc_core_get_lpm_req(pmcdev, pmcdev->pmcs[i]);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> static void
> pmc_add_pmt(struct pmc_dev *pmcdev, u64 ssram_base, void __iomem *ssram)
> {
> @@ -215,3 +349,4 @@ int pmc_core_ssram_init(struct pmc_dev *pmcdev)
> return ret;
> }
> MODULE_IMPORT_NS(INTEL_VSEC);
> +MODULE_IMPORT_NS(INTEL_PMT_TELEMETRY);
>

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

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