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

David E. Box
2023-10-18T23:16:54Z

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);
--
2.34.1