platform/x86:intel/pmc: Create Intel PMC SSRAM Telemetry driver

Convert ssram device related functionalities to a new driver named Intel
PMC SSRAM Telemetry driver. Modify PMC Core driver to use API exported by
the driver to discover and achieve devid and PWRMBASE address information
for each available PMC. PMC Core driver needs to get PCI device when
reading from telemetry regions.

The new SSRAM driver binds to the SSRAM device and provides the following
functionalities:
1. Look for and register telemetry regions available in SSRAM device.
2. Provide devid and PWRMBASE address information for the corresponding
   PMCs.

Signed-off-by: Xi Pardee <xi.pardee@linux.intel.com>
Link: https://lore.kernel.org/r/20250425195237.493129-3-xi.pardee@linux.intel.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

1 files changed, 51 insertions, 22 deletions

diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
index a53a7677122c..2028a769cddb 100644
--- a/drivers/platform/x86/intel/pmc/core.c
+++ b/drivers/platform/x86/intel/pmc/core.c
@@ -29,6 +29,7 @@
 #include <asm/tsc.h>
 
 #include "core.h"
+#include "ssram_telemetry.h"
 #include "../pmt/telemetry.h"
 
 /* Maximum number of modes supported by platfoms that has low power mode capability */
@@ -1354,7 +1355,7 @@ static u32 pmc_core_find_guid(struct pmc_info *list, const struct pmc_reg_map *m
 	return 0;
 }
 
-static int pmc_core_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc)
+static int pmc_core_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc, struct pci_dev *pcidev)
 {
 	struct telem_endpoint *ep;
 	const u8 *lpm_indices;
@@ -1371,7 +1372,7 @@ static int pmc_core_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc)
 	if (!guid)
 		return -ENXIO;
 
-	ep = pmt_telem_find_and_register_endpoint(pmcdev->ssram_pcidev, guid, 0);
+	ep = pmt_telem_find_and_register_endpoint(pcidev, guid, 0);
 	if (IS_ERR(ep)) {
 		dev_dbg(&pmcdev->pdev->dev, "couldn't get telem endpoint %ld",
 			PTR_ERR(ep));
@@ -1455,19 +1456,21 @@ unregister_ep:
 	return ret;
 }
 
-static int pmc_core_ssram_get_lpm_reqs(struct pmc_dev *pmcdev)
+static int pmc_core_ssram_get_lpm_reqs(struct pmc_dev *pmcdev, int func)
 {
+	struct pci_dev *pcidev __free(pci_dev_put) = NULL;
 	unsigned int i;
 	int ret;
 
-	if (!pmcdev->ssram_pcidev)
+	pcidev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(20, func));
+	if (!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]);
+		ret = pmc_core_get_lpm_req(pmcdev, pmcdev->pmcs[i], pcidev);
 		if (ret)
 			return ret;
 	}
@@ -1475,7 +1478,7 @@ static int pmc_core_ssram_get_lpm_reqs(struct pmc_dev *pmcdev)
 	return 0;
 }
 
-const struct pmc_reg_map *pmc_core_find_regmap(struct pmc_info *list, u16 devid)
+static const struct pmc_reg_map *pmc_core_find_regmap(struct pmc_info *list, u16 devid)
 {
 	for (; list->map; ++list)
 		if (devid == list->devid)
@@ -1484,23 +1487,32 @@ const struct pmc_reg_map *pmc_core_find_regmap(struct pmc_info *list, u16 devid)
 	return NULL;
 }
 
-int pmc_core_pmc_add(struct pmc_dev *pmcdev, u64 pwrm_base,
-		     const struct pmc_reg_map *reg_map, unsigned int pmc_index)
+static int pmc_core_pmc_add(struct pmc_dev *pmcdev, unsigned int pmc_index)
+
 {
-	struct pmc *pmc = pmcdev->pmcs[pmc_index];
+	struct pmc_ssram_telemetry pmc_ssram_telemetry;
+	const struct pmc_reg_map *map;
+	struct pmc *pmc;
+	int ret;
+
+	ret = pmc_ssram_telemetry_get_pmc_info(pmc_index, &pmc_ssram_telemetry);
+	if (ret)
+		return ret;
 
-	if (!pwrm_base)
+	map = pmc_core_find_regmap(pmcdev->regmap_list, pmc_ssram_telemetry.devid);
+	if (!map)
 		return -ENODEV;
 
-	/* Memory for primary PMC has been allocated in core.c */
+	pmc = pmcdev->pmcs[pmc_index];
+	/* Memory for primary PMC has been allocated */
 	if (!pmc) {
 		pmc = devm_kzalloc(&pmcdev->pdev->dev, sizeof(*pmc), GFP_KERNEL);
 		if (!pmc)
 			return -ENOMEM;
 	}
 
-	pmc->map = reg_map;
-	pmc->base_addr = pwrm_base;
+	pmc->map = map;
+	pmc->base_addr = pmc_ssram_telemetry.base_addr;
 	pmc->regbase = ioremap(pmc->base_addr, pmc->map->regmap_length);
 
 	if (!pmc->regbase) {
@@ -1513,6 +1525,20 @@ int pmc_core_pmc_add(struct pmc_dev *pmcdev, u64 pwrm_base,
 	return 0;
 }
 
+static int pmc_core_ssram_get_reg_base(struct pmc_dev *pmcdev)
+{
+	int ret;
+
+	ret = pmc_core_pmc_add(pmcdev, PMC_IDX_MAIN);
+	if (ret)
+		return ret;
+
+	pmc_core_pmc_add(pmcdev, PMC_IDX_IOE);
+	pmc_core_pmc_add(pmcdev, PMC_IDX_PCH);
+
+	return 0;
+}
+
 /*
  * When supported, ssram init is used to achieve all available PMCs.
  * If ssram init fails, this function uses legacy method to at least get the
@@ -1530,10 +1556,18 @@ int generic_core_init(struct pmc_dev *pmcdev, struct pmc_dev_info *pmc_dev_info)
 	ssram = pmc_dev_info->regmap_list != NULL;
 	if (ssram) {
 		pmcdev->regmap_list = pmc_dev_info->regmap_list;
-		ret = pmc_core_ssram_init(pmcdev, pmc_dev_info->pci_func);
+		ret = pmc_core_ssram_get_reg_base(pmcdev);
+		/*
+		 * EAGAIN error code indicates Intel PMC SSRAM Telemetry driver
+		 * has not finished probe and PMC info is not available yet. Try
+		 * again later.
+		 */
+		if (ret == -EAGAIN)
+			return -EPROBE_DEFER;
+
 		if (ret) {
 			dev_warn(&pmcdev->pdev->dev,
-				 "ssram init failed, %d, using legacy init\n", ret);
+				 "Failed to get PMC info from SSRAM, %d, using legacy init\n", ret);
 			ssram = false;
 		}
 	}
@@ -1550,7 +1584,7 @@ int generic_core_init(struct pmc_dev *pmcdev, struct pmc_dev_info *pmc_dev_info)
 		pmc_core_punit_pmt_init(pmcdev, pmc_dev_info->dmu_guid);
 
 	if (ssram)
-		return pmc_core_ssram_get_lpm_reqs(pmcdev);
+		return pmc_core_ssram_get_lpm_reqs(pmcdev, pmc_dev_info->pci_func);
 
 	return 0;
 }
@@ -1639,15 +1673,10 @@ static void pmc_core_clean_structure(struct platform_device *pdev)
 	for (i = 0; i < ARRAY_SIZE(pmcdev->pmcs); ++i) {
 		struct pmc *pmc = pmcdev->pmcs[i];
 
-		if (pmc)
+		if (pmc && pmc->regbase)
 			iounmap(pmc->regbase);
 	}
 
-	if (pmcdev->ssram_pcidev) {
-		pci_dev_put(pmcdev->ssram_pcidev);
-		pci_disable_device(pmcdev->ssram_pcidev);
-	}
-
 	if (pmcdev->punit_ep)
 		pmt_telem_unregister_endpoint(pmcdev->punit_ep);