[PATCH v1 0/5] Enable SSRAM support in PTL and LNL

[PATCH v1 0/5] Enable SSRAM support in PTL and LNL

[Xi Pardee]

This series enables SSRAM support, including achieving PMC information
and low power mode substate requirements from telemetry region, in Lunar
Lake and Panther Lake platforms for Intel PMC Core driver. 

The first patch enables SSRAM support for Lunar Lake. The next three
patches introduces a new table in telemetry region to get substate
requirement information for platforms starting from Panther Lake. The
last patch enables SSRAM support for Panther Lake.

Xi Pardee (5):
  platform/x86:intel/pmc: Enable SSRAM support for Lunar Lake
  platform/x86:intel/pmc: Move telemetry endpoint register handling
  platform/x86:intel/pmc: Improve function to show substate header
  platform/x86:intel/pmc: Show substate requirement for S0ix blockers
  platform/x86:intel/pmc: Enable SSRAM support for Panther Lake

 drivers/platform/x86/intel/pmc/arl.c  |   1 +
 drivers/platform/x86/intel/pmc/core.c | 163 +++++++++++++++++++++-----
 drivers/platform/x86/intel/pmc/core.h |  14 +++
 drivers/platform/x86/intel/pmc/lnl.c  |  17 +++
 drivers/platform/x86/intel/pmc/mtl.c  |   1 +
 drivers/platform/x86/intel/pmc/ptl.c  |  30 +++++
 6 files changed, 194 insertions(+), 32 deletions(-)

-- 
2.43.0

[PATCH v1 1/5] platform/x86:intel/pmc: Enable SSRAM support for Lunar Lake

[Xi Pardee]

Enable Lunar Lake platforms to achieve PMC information from
Intel PMC SSRAM Telemetry driver and substate requirements data
from telemetry region.

Signed-off-by: Xi Pardee <xi.pardee@linux.intel.com>
---
 drivers/platform/x86/intel/pmc/lnl.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/platform/x86/intel/pmc/lnl.c b/drivers/platform/x86/intel/pmc/lnl.c
index da513c234714b..e08a77c778c2c 100644
--- a/drivers/platform/x86/intel/pmc/lnl.c
+++ b/drivers/platform/x86/intel/pmc/lnl.c
@@ -13,6 +13,10 @@
 
 #include "core.h"
 
+#define SOCM_LPM_REQ_GUID	0x15099748
+
+static const u8 LNL_LPM_REG_INDEX[] = {0, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 20};
+
 static const struct pmc_bit_map lnl_ltr_show_map[] = {
 	{"SOUTHPORT_A",		CNP_PMC_LTR_SPA},
 	{"SOUTHPORT_B",		CNP_PMC_LTR_SPB},
@@ -528,6 +532,16 @@ static const struct pmc_reg_map lnl_socm_reg_map = {
 	.lpm_live_status_offset = MTL_LPM_LIVE_STATUS_OFFSET,
 	.s0ix_blocker_maps = lnl_blk_maps,
 	.s0ix_blocker_offset = LNL_S0IX_BLOCKER_OFFSET,
+	.lpm_reg_index = LNL_LPM_REG_INDEX,
+};
+
+static struct pmc_info lnl_pmc_info_list[] = {
+	{
+		.guid	= SOCM_LPM_REQ_GUID,
+		.devid	= PMC_DEVID_LNL_SOCM,
+		.map	= &lnl_socm_reg_map,
+	},
+	{}
 };
 
 #define LNL_NPU_PCI_DEV		0x643e
@@ -557,6 +571,8 @@ static int lnl_core_init(struct pmc_dev *pmcdev, struct pmc_dev_info *pmc_dev_in
 }
 
 struct pmc_dev_info lnl_pmc_dev = {
+	.pci_func = 2,
+	.regmap_list = lnl_pmc_info_list,
 	.map = &lnl_socm_reg_map,
 	.suspend = cnl_suspend,
 	.resume = lnl_resume,
-- 
2.43.0

[PATCH v1 2/5] platform/x86:intel/pmc: Move telemetry endpoint register handling

[Xi Pardee]

Move telemetry endpoint handling to pmc_core_get_telem_info(). This
is a preparation patch to introduce a new table to obtain Low Power
Mode substate requirement data for platforms starting from Panther
Lake.

Signed-off-by: Xi Pardee <xi.pardee@linux.intel.com>
---
 drivers/platform/x86/intel/pmc/core.c | 51 +++++++++++++--------------
 1 file changed, 25 insertions(+), 26 deletions(-)

diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
index 540cd2fb0673b..a1dd80bdbd413 100644
--- a/drivers/platform/x86/intel/pmc/core.c
+++ b/drivers/platform/x86/intel/pmc/core.c
@@ -1399,36 +1399,23 @@ static u32 pmc_core_find_guid(struct pmc_info *list, const struct pmc_reg_map *m
  * +----+---------------------------------------------------------+
  *
  */
-static int pmc_core_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc, struct pci_dev *pcidev)
+static int pmc_core_pmt_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc,
+				    struct telem_endpoint *ep)
 {
-	struct telem_endpoint *ep;
 	const u8 *lpm_indices;
 	int num_maps, mode_offset = 0;
 	int ret, mode;
 	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(pcidev, guid, 0);
-	if (IS_ERR(ep)) {
-		dev_dbg(&pmcdev->pdev->dev, "couldn't get telem endpoint %pe", 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;
-	}
+	if (!pmc->lpm_req_regs)
+		return -ENOMEM;
 
 	mode_offset = LPM_HEADER_OFFSET + LPM_MODE_OFFSET;
 	pmc_for_each_mode(mode, pmcdev) {
@@ -1442,23 +1429,21 @@ static int pmc_core_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc, struct
 			if (ret) {
 				dev_err(&pmcdev->pdev->dev,
 					"couldn't read Low Power Mode requirements: %d\n", ret);
-				goto unregister_ep;
+				return ret;
 			}
 			++req_offset;
 		}
 		mode_offset += LPM_REG_COUNT + LPM_MODE_OFFSET;
 	}
-
-unregister_ep:
-	pmt_telem_unregister_endpoint(ep);
-
 	return ret;
 }
 
-static int pmc_core_ssram_get_lpm_reqs(struct pmc_dev *pmcdev, int func)
+static int pmc_core_get_telem_info(struct pmc_dev *pmcdev, int func)
 {
 	struct pci_dev *pcidev __free(pci_dev_put) = NULL;
+	struct telem_endpoint *ep;
 	unsigned int i;
+	u32 guid;
 	int ret;
 
 	pcidev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(20, func));
@@ -1466,10 +1451,24 @@ static int pmc_core_ssram_get_lpm_reqs(struct pmc_dev *pmcdev, int func)
 		return -ENODEV;
 
 	for (i = 0; i < ARRAY_SIZE(pmcdev->pmcs); ++i) {
-		if (!pmcdev->pmcs[i])
+		struct pmc *pmc;
+
+		pmc = pmcdev->pmcs[i];
+		if (!pmc)
 			continue;
 
-		ret = pmc_core_get_lpm_req(pmcdev, pmcdev->pmcs[i], pcidev);
+		guid = pmc_core_find_guid(pmcdev->regmap_list, pmc->map);
+		if (!guid)
+			return -ENXIO;
+
+		ep = pmt_telem_find_and_register_endpoint(pcidev, guid, 0);
+		if (IS_ERR(ep)) {
+			dev_dbg(&pmcdev->pdev->dev, "couldn't get telem endpoint %pe", ep);
+			return -EPROBE_DEFER;
+		}
+
+		ret = pmc_core_pmt_get_lpm_req(pmcdev, pmc, ep);
+		pmt_telem_unregister_endpoint(ep);
 		if (ret)
 			return ret;
 	}
@@ -1583,7 +1582,7 @@ 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) {
-		ret = pmc_core_ssram_get_lpm_reqs(pmcdev, pmc_dev_info->pci_func);
+		ret = pmc_core_get_telem_info(pmcdev, pmc_dev_info->pci_func);
 		if (ret)
 			goto unmap_regbase;
 	}
-- 
2.43.0

[PATCH v1 3/5] platform/x86:intel/pmc: Improve function to show substate header

[Xi Pardee]

Refactor pmc_core_substate_req_header_show() to accept a new argument.
This is a preparation patch to introduce a new way to show Low Power
Mode substate requirement data for platforms starting from Panther
Lake. Increased the size for the name column as the Low Power Mode
requirement register name is longer in newer platforms.

Signed-off-by: Xi Pardee <xi.pardee@linux.intel.com>
---
 drivers/platform/x86/intel/pmc/core.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
index a1dd80bdbd413..47cc5120e7dd6 100644
--- a/drivers/platform/x86/intel/pmc/core.c
+++ b/drivers/platform/x86/intel/pmc/core.c
@@ -828,17 +828,20 @@ static int pmc_core_substate_l_sts_regs_show(struct seq_file *s, void *unused)
 }
 DEFINE_SHOW_ATTRIBUTE(pmc_core_substate_l_sts_regs);
 
-static void pmc_core_substate_req_header_show(struct seq_file *s, int pmc_index)
+static void pmc_core_substate_req_header_show(struct seq_file *s, int pmc_index, char *name)
 {
 	struct pmc_dev *pmcdev = s->private;
 	int mode;
 
-	seq_printf(s, "%30s |", "Element");
+	seq_printf(s, "%40s |", "Element");
 	pmc_for_each_mode(mode, pmcdev)
 		seq_printf(s, " %9s |", pmc_lpm_modes[mode]);
 
-	seq_printf(s, " %9s |", "Status");
-	seq_printf(s, " %11s |\n", "Live Status");
+	if (!strcmp(name, "Status")) {
+		seq_printf(s, " %9s |", name);
+		seq_printf(s, " %11s |\n", "Live Status");
+	} else
+		seq_printf(s, " %9s |\n", name);
 }
 
 static int pmc_core_substate_req_regs_show(struct seq_file *s, void *unused)
@@ -872,7 +875,7 @@ static int pmc_core_substate_req_regs_show(struct seq_file *s, void *unused)
 			continue;
 
 		/* Display the header */
-		pmc_core_substate_req_header_show(s, pmc_index);
+		pmc_core_substate_req_header_show(s, pmc_index, "Status");
 
 		/* Loop over maps */
 		for (mp = 0; mp < num_maps; mp++) {
@@ -910,7 +913,7 @@ static int pmc_core_substate_req_regs_show(struct seq_file *s, void *unused)
 				}
 
 				/* Display the element name in the first column */
-				seq_printf(s, "pmc%d: %26s |", pmc_index, map[i].name);
+				seq_printf(s, "pmc%d: %34s |", pmc_index, map[i].name);
 
 				/* Loop over the enabled states and display if required */
 				pmc_for_each_mode(mode, pmcdev) {
-- 
2.43.0

[PATCH v1 4/5] platform/x86:intel/pmc: Show substate requirement for S0ix blockers

[Xi Pardee]

Add support to read and show S0ix blocker substate requirements.
Starting from Panther Lake, substate requirement data is provided
based on S0ix blockers instead of all low power mode requirements.
For platforms that support this new feature, add support to display
substate requirements based on S0ix blockers.
Change the "substate_requirements" attribute of Intel PMC Core
driver to show the substate requirements for each S0ix blocker
and the corresponding S0ix blocker value.

Signed-off-by: Xi Pardee <xi.pardee@linux.intel.com>
---
 drivers/platform/x86/intel/pmc/arl.c  |   1 +
 drivers/platform/x86/intel/pmc/core.c | 109 ++++++++++++++++++++++++--
 drivers/platform/x86/intel/pmc/core.h |  12 +++
 drivers/platform/x86/intel/pmc/lnl.c  |   1 +
 drivers/platform/x86/intel/pmc/mtl.c  |   1 +
 5 files changed, 118 insertions(+), 6 deletions(-)

diff --git a/drivers/platform/x86/intel/pmc/arl.c b/drivers/platform/x86/intel/pmc/arl.c
index 9d66d65e75779..f04c67738d721 100644
--- a/drivers/platform/x86/intel/pmc/arl.c
+++ b/drivers/platform/x86/intel/pmc/arl.c
@@ -732,6 +732,7 @@ struct pmc_dev_info arl_pmc_dev = {
 
 struct pmc_dev_info arl_h_pmc_dev = {
 	.pci_func = 2,
+	.telem_info = SUB_REQ_LPM,
 	.dmu_guid = ARL_PMT_DMU_GUID,
 	.regmap_list = arl_pmc_info_list,
 	.map = &mtl_socm_reg_map,
diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
index 47cc5120e7dd6..026a28bb7509c 100644
--- a/drivers/platform/x86/intel/pmc/core.c
+++ b/drivers/platform/x86/intel/pmc/core.c
@@ -844,6 +844,56 @@ static void pmc_core_substate_req_header_show(struct seq_file *s, int pmc_index,
 		seq_printf(s, " %9s |\n", name);
 }
 
+static int pmc_core_substate_blk_req_show(struct seq_file *s, void *unused)
+{
+	struct pmc_dev *pmcdev = s->private;
+	unsigned int pmc_index;
+	u32 *blk_sub_req_regs;
+
+	for (pmc_index = 0; pmc_index < ARRAY_SIZE(pmcdev->pmcs); pmc_index++) {
+		const struct pmc_bit_map **maps;
+		unsigned int arr_size, r_idx;
+		u32 offset, counter;
+		struct pmc *pmc;
+
+		pmc = pmcdev->pmcs[pmc_index];
+		if (!pmc || !pmc->blk_sub_req_regs)
+			continue;
+
+		blk_sub_req_regs = pmc->blk_sub_req_regs;
+		maps = pmc->map->s0ix_blocker_maps;
+		offset = pmc->map->s0ix_blocker_offset;
+		arr_size = pmc_core_lpm_get_arr_size(maps);
+
+		/* Display the header */
+		pmc_core_substate_req_header_show(s, pmc_index, "Value");
+
+		for (r_idx = 0; r_idx < arr_size; r_idx++) {
+			const struct pmc_bit_map *map;
+
+			for (map = maps[r_idx]; map->name; map++) {
+				int mode;
+
+				if (!map->blk)
+					continue;
+
+				counter = pmc_core_reg_read(pmc, offset);
+				seq_printf(s, "pmc%d: %34s |", pmc_index, map->name);
+				pmc_for_each_mode(mode, pmcdev) {
+					bool required = *blk_sub_req_regs & BIT(mode);
+
+					seq_printf(s, " %9s |", required ? "Required" : " ");
+				}
+				seq_printf(s, " %9d |\n", counter);
+				offset += map->blk * S0IX_BLK_SIZE;
+				blk_sub_req_regs++;
+			}
+		}
+	}
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(pmc_core_substate_blk_req);
+
 static int pmc_core_substate_req_regs_show(struct seq_file *s, void *unused)
 {
 	struct pmc_dev *pmcdev = s->private;
@@ -1335,7 +1385,10 @@ static void pmc_core_dbgfs_register(struct pmc_dev *pmcdev)
 		debugfs_create_file("substate_requirements", 0444,
 				    pmcdev->dbgfs_dir, pmcdev,
 				    &pmc_core_substate_req_regs_fops);
-	}
+	} else if (primary_pmc->blk_sub_req_regs)
+		debugfs_create_file("substate_requirements", 0444,
+				    pmcdev->dbgfs_dir, pmcdev,
+				    &pmc_core_substate_blk_req_fops);
 
 	if (primary_pmc->map->pson_residency_offset && pmc_core_is_pson_residency_enabled(pmcdev)) {
 		debugfs_create_file("pson_residency_usec", 0444,
@@ -1441,7 +1494,38 @@ static int pmc_core_pmt_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc,
 	return ret;
 }
 
-static int pmc_core_get_telem_info(struct pmc_dev *pmcdev, int func)
+static int pmc_core_pmt_get_blk_sub_req(struct pmc_dev *pmcdev, struct pmc *pmc,
+					struct telem_endpoint *ep)
+{
+	u32 num_blocker, sample_id;
+	unsigned int index;
+	u32 *req_offset;
+	int ret;
+
+	num_blocker = pmc->map->num_s0ix_blocker;
+	sample_id = pmc->map->blocker_req_offset;
+
+	pmc->blk_sub_req_regs = devm_kzalloc(&pmcdev->pdev->dev,
+					 num_blocker * sizeof(u32),
+					 GFP_KERNEL);
+	if (!pmc->blk_sub_req_regs)
+		ret = -ENOMEM;
+
+	req_offset = pmc->blk_sub_req_regs;
+	for (index = 0; index < num_blocker; index++) {
+		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);
+			return ret;
+		}
+		sample_id++;
+		req_offset++;
+	}
+	return ret;
+}
+
+static int pmc_core_get_telem_info(struct pmc_dev *pmcdev, int func, unsigned int telem_info)
 {
 	struct pci_dev *pcidev __free(pci_dev_put) = NULL;
 	struct telem_endpoint *ep;
@@ -1470,13 +1554,24 @@ static int pmc_core_get_telem_info(struct pmc_dev *pmcdev, int func)
 			return -EPROBE_DEFER;
 		}
 
-		ret = pmc_core_pmt_get_lpm_req(pmcdev, pmc, ep);
-		pmt_telem_unregister_endpoint(ep);
+		if (telem_info & SUB_REQ_LPM)
+			ret = pmc_core_pmt_get_lpm_req(pmcdev, pmc, ep);
 		if (ret)
-			return ret;
+			goto unregister_ep;
+
+		if (telem_info & SUB_REQ_BLK)
+			ret = pmc_core_pmt_get_blk_sub_req(pmcdev, pmc, ep);
+		if (ret)
+			goto unregister_ep;
+
+		pmt_telem_unregister_endpoint(ep);
 	}
 
 	return 0;
+
+unregister_ep:
+	pmt_telem_unregister_endpoint(ep);
+	return ret;
 }
 
 static const struct pmc_reg_map *pmc_core_find_regmap(struct pmc_info *list, u16 devid)
@@ -1585,7 +1680,9 @@ 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) {
-		ret = pmc_core_get_telem_info(pmcdev, pmc_dev_info->pci_func);
+		ret = pmc_core_get_telem_info(pmcdev,
+					      pmc_dev_info->pci_func,
+					      pmc_dev_info->telem_info);
 		if (ret)
 			goto unmap_regbase;
 	}
diff --git a/drivers/platform/x86/intel/pmc/core.h b/drivers/platform/x86/intel/pmc/core.h
index 4a94a4ee031e6..d8c7b28493055 100644
--- a/drivers/platform/x86/intel/pmc/core.h
+++ b/drivers/platform/x86/intel/pmc/core.h
@@ -29,6 +29,10 @@ struct telem_endpoint;
 #define LPM_REG_COUNT		28
 #define LPM_MODE_OFFSET		1
 
+/* Telemetry Endpoint Info bits */
+#define SUB_REQ_LPM		0x01	/* Substate requirement for low power mode requirements */
+#define SUB_REQ_BLK		0x02	/* Substate requirement for S0ix blockers */
+
 /* Sunrise Point Power Management Controller PCI Device ID */
 #define SPT_PMC_PCI_DEVICE_ID			0x9d21
 #define SPT_PMC_BASE_ADDR_OFFSET		0x48
@@ -344,6 +348,8 @@ struct pmc_bit_map {
  * @pm_read_disable_bit: Bit index to read PMC_READ_DISABLE
  * @slps0_dbg_offset:	PWRMBASE offset to SLP_S0_DEBUG_REG*
  * @s0ix_blocker_offset PWRMBASE offset to S0ix blocker counter
+ * @num_s0ix_blocker:	Number of S0ix blockers
+ * @blocker_req_offset:	Telemetry offset to S0ix blocker low power mode substate requirement table
  *
  * Each PCH has unique set of register offsets and bit indexes. This structure
  * captures them to have a common implementation.
@@ -369,6 +375,8 @@ struct pmc_reg_map {
 	const u32 ltr_ignore_max;
 	const u32 pm_vric1_offset;
 	const u32 s0ix_blocker_offset;
+	const u32 num_s0ix_blocker;
+	const u32 blocker_req_offset;
 	/* Low Power Mode registers */
 	const int lpm_num_maps;
 	const int lpm_num_modes;
@@ -404,6 +412,7 @@ struct pmc_info {
  * @map:		pointer to pmc_reg_map struct that contains platform
  *			specific attributes
  * @lpm_req_regs:	List of substate requirements
+ * @blk_sub_req_reqs:	List of registers showing substate requirements for S0ix blockers
  * @ltr_ign:		Holds LTR ignore data while suspended
  *
  * pmc contains info about one power management controller device.
@@ -413,6 +422,7 @@ struct pmc {
 	void __iomem *regbase;
 	const struct pmc_reg_map *map;
 	u32 *lpm_req_regs;
+	u32 *blk_sub_req_regs;
 	u32 ltr_ign;
 };
 
@@ -468,6 +478,7 @@ enum pmc_index {
 /**
  * struct pmc_dev_info - Structure to keep PMC device info
  * @pci_func:		Function number of the primary PMC
+ * @telem_info:		Bitmask to indicate which telemetry info is available
  * @dmu_guid:		Die Management Unit GUID
  * @regmap_list:	Pointer to a list of pmc_info structure that could be
  *			available for the platform. When set, this field implies
@@ -480,6 +491,7 @@ enum pmc_index {
  */
 struct pmc_dev_info {
 	u8 pci_func;
+	u8 telem_info;
 	u32 dmu_guid;
 	struct pmc_info *regmap_list;
 	const struct pmc_reg_map *map;
diff --git a/drivers/platform/x86/intel/pmc/lnl.c b/drivers/platform/x86/intel/pmc/lnl.c
index e08a77c778c2c..ec9e79f6cd913 100644
--- a/drivers/platform/x86/intel/pmc/lnl.c
+++ b/drivers/platform/x86/intel/pmc/lnl.c
@@ -572,6 +572,7 @@ static int lnl_core_init(struct pmc_dev *pmcdev, struct pmc_dev_info *pmc_dev_in
 
 struct pmc_dev_info lnl_pmc_dev = {
 	.pci_func = 2,
+	.telem_info = SUB_REQ_LPM,
 	.regmap_list = lnl_pmc_info_list,
 	.map = &lnl_socm_reg_map,
 	.suspend = cnl_suspend,
diff --git a/drivers/platform/x86/intel/pmc/mtl.c b/drivers/platform/x86/intel/pmc/mtl.c
index faa13a7ee688f..c58a871e2e0df 100644
--- a/drivers/platform/x86/intel/pmc/mtl.c
+++ b/drivers/platform/x86/intel/pmc/mtl.c
@@ -994,6 +994,7 @@ static int mtl_core_init(struct pmc_dev *pmcdev, struct pmc_dev_info *pmc_dev_in
 
 struct pmc_dev_info mtl_pmc_dev = {
 	.pci_func = 2,
+	.telem_info = SUB_REQ_LPM,
 	.dmu_guid = MTL_PMT_DMU_GUID,
 	.regmap_list = mtl_pmc_info_list,
 	.map = &mtl_socm_reg_map,
-- 
2.43.0

[PATCH v1 5/5] platform/x86:intel/pmc: Enable SSRAM support for Panther Lake

[Xi Pardee]

Enable Panther Lake platforms to achieve PMC information from
Intel PMC SSRAM Telemetry driver and substate requirements data
from telemetry region.

Signed-off-by: Xi Pardee <xi.pardee@linux.intel.com>
---
 drivers/platform/x86/intel/pmc/core.h |  2 ++
 drivers/platform/x86/intel/pmc/ptl.c  | 30 +++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/drivers/platform/x86/intel/pmc/core.h b/drivers/platform/x86/intel/pmc/core.h
index d8c7b28493055..cdb32f2203cff 100644
--- a/drivers/platform/x86/intel/pmc/core.h
+++ b/drivers/platform/x86/intel/pmc/core.h
@@ -301,6 +301,8 @@ enum ppfear_regs {
 #define PTL_PMC_LTR_CUR_ASLT			0x1C28
 #define PTL_PMC_LTR_CUR_PLT			0x1C2C
 #define PTL_PCD_PMC_MMIO_REG_LEN		0x31A8
+#define PTL_NUM_S0IX_BLOCKER			106
+#define PTL_BLK_REQ_OFFSET			55
 
 /* SSRAM PMC Device ID */
 /* LNL */
diff --git a/drivers/platform/x86/intel/pmc/ptl.c b/drivers/platform/x86/intel/pmc/ptl.c
index 394515af60d60..48be79b4e769f 100644
--- a/drivers/platform/x86/intel/pmc/ptl.c
+++ b/drivers/platform/x86/intel/pmc/ptl.c
@@ -10,6 +10,17 @@
 
 #include "core.h"
 
+/* PMC SSRAM PMT Telemetry GUIDS */
+#define PCDP_LPM_REQ_GUID 0x47179370
+
+/*
+ * Die Mapping to Product.
+ * Product PCDDie
+ * PTL-H   PCD-H
+ * PTL-P   PCD-P
+ * PTL-U   PCD-P
+ */
+
 static const struct pmc_bit_map ptl_pcdp_pfear_map[] = {
 	{"PMC_0",               BIT(0)},
 	{"FUSE_OSSE",           BIT(1)},
@@ -515,6 +526,22 @@ static const struct pmc_reg_map ptl_pcdp_reg_map = {
 	.lpm_live_status_offset = MTL_LPM_LIVE_STATUS_OFFSET,
 	.s0ix_blocker_maps = ptl_pcdp_blk_maps,
 	.s0ix_blocker_offset = LNL_S0IX_BLOCKER_OFFSET,
+	.num_s0ix_blocker = PTL_NUM_S0IX_BLOCKER,
+	.blocker_req_offset = PTL_BLK_REQ_OFFSET,
+};
+
+static struct pmc_info ptl_pmc_info_list[] = {
+	{
+		.guid	= PCDP_LPM_REQ_GUID,
+		.devid	= PMC_DEVID_PTL_PCDH,
+		.map	= &ptl_pcdp_reg_map,
+	},
+	{
+		.guid   = PCDP_LPM_REQ_GUID,
+		.devid  = PMC_DEVID_PTL_PCDP,
+		.map    = &ptl_pcdp_reg_map,
+	},
+	{}
 };
 
 #define PTL_NPU_PCI_DEV                0xb03e
@@ -543,6 +570,9 @@ static int ptl_core_init(struct pmc_dev *pmcdev, struct pmc_dev_info *pmc_dev_in
 }
 
 struct pmc_dev_info ptl_pmc_dev = {
+	.pci_func = 2,
+	.telem_info = SUB_REQ_BLK,
+	.regmap_list = ptl_pmc_info_list,
 	.map = &ptl_pcdp_reg_map,
 	.suspend = cnl_suspend,
 	.resume = ptl_resume,
-- 
2.43.0

Re: [PATCH v1 4/5] platform/x86:intel/pmc: Show substate requirement for S0ix blockers

[Dan Carpenter]

Hi Xi,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Xi-Pardee/platform-x86-intel-pmc-Enable-SSRAM-support-for-Lunar-Lake/20250622-050804
base:   linus/master
patch link:    https://lore.kernel.org/r/20250621210529.237964-5-xi.pardee%40linux.intel.com
patch subject: [PATCH v1 4/5] platform/x86:intel/pmc: Show substate requirement for S0ix blockers
config: i386-randconfig-141-20250623 (https://download.01.org/0day-ci/archive/20250624/202506241840.0POVt4tf-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202506241840.0POVt4tf-lkp@intel.com/

New smatch warnings:
drivers/platform/x86/intel/pmc/core.c:1525 pmc_core_pmt_get_blk_sub_req() error: uninitialized symbol 'ret'.
drivers/platform/x86/intel/pmc/core.c:1559 pmc_core_get_telem_info() error: uninitialized symbol 'ret'.

vim +/ret +1525 drivers/platform/x86/intel/pmc/core.c

f3435ca196060d Xi Pardee 2025-06-21  1497  static int pmc_core_pmt_get_blk_sub_req(struct pmc_dev *pmcdev, struct pmc *pmc,
f3435ca196060d Xi Pardee 2025-06-21  1498  					struct telem_endpoint *ep)
f3435ca196060d Xi Pardee 2025-06-21  1499  {
f3435ca196060d Xi Pardee 2025-06-21  1500  	u32 num_blocker, sample_id;
f3435ca196060d Xi Pardee 2025-06-21  1501  	unsigned int index;
f3435ca196060d Xi Pardee 2025-06-21  1502  	u32 *req_offset;
f3435ca196060d Xi Pardee 2025-06-21  1503  	int ret;
f3435ca196060d Xi Pardee 2025-06-21  1504  
f3435ca196060d Xi Pardee 2025-06-21  1505  	num_blocker = pmc->map->num_s0ix_blocker;
f3435ca196060d Xi Pardee 2025-06-21  1506  	sample_id = pmc->map->blocker_req_offset;
f3435ca196060d Xi Pardee 2025-06-21  1507  
f3435ca196060d Xi Pardee 2025-06-21  1508  	pmc->blk_sub_req_regs = devm_kzalloc(&pmcdev->pdev->dev,
f3435ca196060d Xi Pardee 2025-06-21  1509  					 num_blocker * sizeof(u32),

Use devm_kcalloc() so we don't have to check if num_blocker can be
greater than UINT_MAX / 4 on 32bit systems.

f3435ca196060d Xi Pardee 2025-06-21  1510  					 GFP_KERNEL);
f3435ca196060d Xi Pardee 2025-06-21  1511  	if (!pmc->blk_sub_req_regs)
f3435ca196060d Xi Pardee 2025-06-21  1512  		ret = -ENOMEM;

s/ret = /return /.  Otherwise it leads to a NULL pointer dereference.

f3435ca196060d Xi Pardee 2025-06-21  1513  
f3435ca196060d Xi Pardee 2025-06-21  1514  	req_offset = pmc->blk_sub_req_regs;
f3435ca196060d Xi Pardee 2025-06-21  1515  	for (index = 0; index < num_blocker; index++) {

smatch doesn't know if num_blocker can be zero.

f3435ca196060d Xi Pardee 2025-06-21  1516  		ret = pmt_telem_read32(ep, sample_id, req_offset, 1);
f3435ca196060d Xi Pardee 2025-06-21  1517  		if (ret) {
f3435ca196060d Xi Pardee 2025-06-21  1518  			dev_err(&pmcdev->pdev->dev,
f3435ca196060d Xi Pardee 2025-06-21  1519  				"couldn't read Low Power Mode requirements: %d\n", ret);
f3435ca196060d Xi Pardee 2025-06-21  1520  			return ret;
f3435ca196060d Xi Pardee 2025-06-21  1521  		}
f3435ca196060d Xi Pardee 2025-06-21  1522  		sample_id++;
f3435ca196060d Xi Pardee 2025-06-21  1523  		req_offset++;
f3435ca196060d Xi Pardee 2025-06-21  1524  	}
f3435ca196060d Xi Pardee 2025-06-21 @1525  	return ret;
f3435ca196060d Xi Pardee 2025-06-21  1526  }
f3435ca196060d Xi Pardee 2025-06-21  1527  
f3435ca196060d Xi Pardee 2025-06-21  1528  static int pmc_core_get_telem_info(struct pmc_dev *pmcdev, int func, unsigned int telem_info)
78a7491d5cba8b Xi Pardee 2025-04-09  1529  {
b5d46539626833 Xi Pardee 2025-04-25  1530  	struct pci_dev *pcidev __free(pci_dev_put) = NULL;
d7bc7e19147769 Xi Pardee 2025-06-21  1531  	struct telem_endpoint *ep;
052fabddeaa70b Xi Pardee 2025-04-09  1532  	unsigned int i;
d7bc7e19147769 Xi Pardee 2025-06-21  1533  	u32 guid;
052fabddeaa70b Xi Pardee 2025-04-09  1534  	int ret;
78a7491d5cba8b Xi Pardee 2025-04-09  1535  
b5d46539626833 Xi Pardee 2025-04-25  1536  	pcidev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(20, func));
b5d46539626833 Xi Pardee 2025-04-25  1537  	if (!pcidev)
78a7491d5cba8b Xi Pardee 2025-04-09  1538  		return -ENODEV;
78a7491d5cba8b Xi Pardee 2025-04-09  1539  
78a7491d5cba8b Xi Pardee 2025-04-09  1540  	for (i = 0; i < ARRAY_SIZE(pmcdev->pmcs); ++i) {
d7bc7e19147769 Xi Pardee 2025-06-21  1541  		struct pmc *pmc;
d7bc7e19147769 Xi Pardee 2025-06-21  1542  
d7bc7e19147769 Xi Pardee 2025-06-21  1543  		pmc = pmcdev->pmcs[i];
d7bc7e19147769 Xi Pardee 2025-06-21  1544  		if (!pmc)
78a7491d5cba8b Xi Pardee 2025-04-09  1545  			continue;
78a7491d5cba8b Xi Pardee 2025-04-09  1546  
d7bc7e19147769 Xi Pardee 2025-06-21  1547  		guid = pmc_core_find_guid(pmcdev->regmap_list, pmc->map);
d7bc7e19147769 Xi Pardee 2025-06-21  1548  		if (!guid)
d7bc7e19147769 Xi Pardee 2025-06-21  1549  			return -ENXIO;
d7bc7e19147769 Xi Pardee 2025-06-21  1550  
d7bc7e19147769 Xi Pardee 2025-06-21  1551  		ep = pmt_telem_find_and_register_endpoint(pcidev, guid, 0);
d7bc7e19147769 Xi Pardee 2025-06-21  1552  		if (IS_ERR(ep)) {
d7bc7e19147769 Xi Pardee 2025-06-21  1553  			dev_dbg(&pmcdev->pdev->dev, "couldn't get telem endpoint %pe", ep);
d7bc7e19147769 Xi Pardee 2025-06-21  1554  			return -EPROBE_DEFER;
d7bc7e19147769 Xi Pardee 2025-06-21  1555  		}
d7bc7e19147769 Xi Pardee 2025-06-21  1556  
f3435ca196060d Xi Pardee 2025-06-21  1557  		if (telem_info & SUB_REQ_LPM)
d7bc7e19147769 Xi Pardee 2025-06-21  1558  			ret = pmc_core_pmt_get_lpm_req(pmcdev, pmc, ep);

ret is uninitialized on else path.  I generally encourage developers
to set CONFIG_INIT_STACK_ALL_PATTERN=y for their testing.

78a7491d5cba8b Xi Pardee 2025-04-09 @1559  		if (ret)
f3435ca196060d Xi Pardee 2025-06-21  1560  			goto unregister_ep;
f3435ca196060d Xi Pardee 2025-06-21  1561  
f3435ca196060d Xi Pardee 2025-06-21  1562  		if (telem_info & SUB_REQ_BLK)
f3435ca196060d Xi Pardee 2025-06-21  1563  			ret = pmc_core_pmt_get_blk_sub_req(pmcdev, pmc, ep);
f3435ca196060d Xi Pardee 2025-06-21  1564  		if (ret)
f3435ca196060d Xi Pardee 2025-06-21  1565  			goto unregister_ep;
f3435ca196060d Xi Pardee 2025-06-21  1566  
f3435ca196060d Xi Pardee 2025-06-21  1567  		pmt_telem_unregister_endpoint(ep);
78a7491d5cba8b Xi Pardee 2025-04-09  1568  	}
78a7491d5cba8b Xi Pardee 2025-04-09  1569  
78a7491d5cba8b Xi Pardee 2025-04-09  1570  	return 0;
f3435ca196060d Xi Pardee 2025-06-21  1571  
f3435ca196060d Xi Pardee 2025-06-21  1572  unregister_ep:
f3435ca196060d Xi Pardee 2025-06-21  1573  	pmt_telem_unregister_endpoint(ep);
f3435ca196060d Xi Pardee 2025-06-21  1574  	return ret;
78a7491d5cba8b Xi Pardee 2025-04-09  1575  }

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v1 4/5] platform/x86:intel/pmc: Show substate requirement for S0ix blockers

[Xi Pardee]

Hi Dan,

Thanks for reviewing. My responses are in line.

Xi

On 6/24/2025 7:45 AM, Dan Carpenter wrote:
> Hi Xi,
>
> kernel test robot noticed the following build warnings:
>
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Xi-Pardee/platform-x86-intel-pmc-Enable-SSRAM-support-for-Lunar-Lake/20250622-050804
> base:   linus/master
> patch link:    https://lore.kernel.org/r/20250621210529.237964-5-xi.pardee%40linux.intel.com
> patch subject: [PATCH v1 4/5] platform/x86:intel/pmc: Show substate requirement for S0ix blockers
> config: i386-randconfig-141-20250623 (https://download.01.org/0day-ci/archive/20250624/202506241840.0POVt4tf-lkp@intel.com/config)
> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> | Closes: https://lore.kernel.org/r/202506241840.0POVt4tf-lkp@intel.com/
>
> New smatch warnings:
> drivers/platform/x86/intel/pmc/core.c:1525 pmc_core_pmt_get_blk_sub_req() error: uninitialized symbol 'ret'.
> drivers/platform/x86/intel/pmc/core.c:1559 pmc_core_get_telem_info() error: uninitialized symbol 'ret'.
>
> vim +/ret +1525 drivers/platform/x86/intel/pmc/core.c
>
> f3435ca196060d Xi Pardee 2025-06-21  1497  static int pmc_core_pmt_get_blk_sub_req(struct pmc_dev *pmcdev, struct pmc *pmc,
> f3435ca196060d Xi Pardee 2025-06-21  1498  					struct telem_endpoint *ep)
> f3435ca196060d Xi Pardee 2025-06-21  1499  {
> f3435ca196060d Xi Pardee 2025-06-21  1500  	u32 num_blocker, sample_id;
> f3435ca196060d Xi Pardee 2025-06-21  1501  	unsigned int index;
> f3435ca196060d Xi Pardee 2025-06-21  1502  	u32 *req_offset;
> f3435ca196060d Xi Pardee 2025-06-21  1503  	int ret;
> f3435ca196060d Xi Pardee 2025-06-21  1504
> f3435ca196060d Xi Pardee 2025-06-21  1505  	num_blocker = pmc->map->num_s0ix_blocker;
> f3435ca196060d Xi Pardee 2025-06-21  1506  	sample_id = pmc->map->blocker_req_offset;
> f3435ca196060d Xi Pardee 2025-06-21  1507
> f3435ca196060d Xi Pardee 2025-06-21  1508  	pmc->blk_sub_req_regs = devm_kzalloc(&pmcdev->pdev->dev,
> f3435ca196060d Xi Pardee 2025-06-21  1509  					 num_blocker * sizeof(u32),
>
> Use devm_kcalloc() so we don't have to check if num_blocker can be
> greater than UINT_MAX / 4 on 32bit systems.
Will change to use devm_kcalloc() in next version.
>
> f3435ca196060d Xi Pardee 2025-06-21  1510  					 GFP_KERNEL);
> f3435ca196060d Xi Pardee 2025-06-21  1511  	if (!pmc->blk_sub_req_regs)
> f3435ca196060d Xi Pardee 2025-06-21  1512  		ret = -ENOMEM;
>
> s/ret = /return /.  Otherwise it leads to a NULL pointer dereference.
Will change to return in next version
>
> f3435ca196060d Xi Pardee 2025-06-21  1513
> f3435ca196060d Xi Pardee 2025-06-21  1514  	req_offset = pmc->blk_sub_req_regs;
> f3435ca196060d Xi Pardee 2025-06-21  1515  	for (index = 0; index < num_blocker; index++) {
>
> smatch doesn't know if num_blocker can be zero.
Will initialize ret to be 0 in next version.
>
> f3435ca196060d Xi Pardee 2025-06-21  1516  		ret = pmt_telem_read32(ep, sample_id, req_offset, 1);
> f3435ca196060d Xi Pardee 2025-06-21  1517  		if (ret) {
> f3435ca196060d Xi Pardee 2025-06-21  1518  			dev_err(&pmcdev->pdev->dev,
> f3435ca196060d Xi Pardee 2025-06-21  1519  				"couldn't read Low Power Mode requirements: %d\n", ret);
> f3435ca196060d Xi Pardee 2025-06-21  1520  			return ret;
> f3435ca196060d Xi Pardee 2025-06-21  1521  		}
> f3435ca196060d Xi Pardee 2025-06-21  1522  		sample_id++;
> f3435ca196060d Xi Pardee 2025-06-21  1523  		req_offset++;
> f3435ca196060d Xi Pardee 2025-06-21  1524  	}
> f3435ca196060d Xi Pardee 2025-06-21 @1525  	return ret;
> f3435ca196060d Xi Pardee 2025-06-21  1526  }
> f3435ca196060d Xi Pardee 2025-06-21  1527
> f3435ca196060d Xi Pardee 2025-06-21  1528  static int pmc_core_get_telem_info(struct pmc_dev *pmcdev, int func, unsigned int telem_info)
> 78a7491d5cba8b Xi Pardee 2025-04-09  1529  {
> b5d46539626833 Xi Pardee 2025-04-25  1530  	struct pci_dev *pcidev __free(pci_dev_put) = NULL;
> d7bc7e19147769 Xi Pardee 2025-06-21  1531  	struct telem_endpoint *ep;
> 052fabddeaa70b Xi Pardee 2025-04-09  1532  	unsigned int i;
> d7bc7e19147769 Xi Pardee 2025-06-21  1533  	u32 guid;
> 052fabddeaa70b Xi Pardee 2025-04-09  1534  	int ret;
> 78a7491d5cba8b Xi Pardee 2025-04-09  1535
> b5d46539626833 Xi Pardee 2025-04-25  1536  	pcidev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(20, func));
> b5d46539626833 Xi Pardee 2025-04-25  1537  	if (!pcidev)
> 78a7491d5cba8b Xi Pardee 2025-04-09  1538  		return -ENODEV;
> 78a7491d5cba8b Xi Pardee 2025-04-09  1539
> 78a7491d5cba8b Xi Pardee 2025-04-09  1540  	for (i = 0; i < ARRAY_SIZE(pmcdev->pmcs); ++i) {
> d7bc7e19147769 Xi Pardee 2025-06-21  1541  		struct pmc *pmc;
> d7bc7e19147769 Xi Pardee 2025-06-21  1542
> d7bc7e19147769 Xi Pardee 2025-06-21  1543  		pmc = pmcdev->pmcs[i];
> d7bc7e19147769 Xi Pardee 2025-06-21  1544  		if (!pmc)
> 78a7491d5cba8b Xi Pardee 2025-04-09  1545  			continue;
> 78a7491d5cba8b Xi Pardee 2025-04-09  1546
> d7bc7e19147769 Xi Pardee 2025-06-21  1547  		guid = pmc_core_find_guid(pmcdev->regmap_list, pmc->map);
> d7bc7e19147769 Xi Pardee 2025-06-21  1548  		if (!guid)
> d7bc7e19147769 Xi Pardee 2025-06-21  1549  			return -ENXIO;
> d7bc7e19147769 Xi Pardee 2025-06-21  1550
> d7bc7e19147769 Xi Pardee 2025-06-21  1551  		ep = pmt_telem_find_and_register_endpoint(pcidev, guid, 0);
> d7bc7e19147769 Xi Pardee 2025-06-21  1552  		if (IS_ERR(ep)) {
> d7bc7e19147769 Xi Pardee 2025-06-21  1553  			dev_dbg(&pmcdev->pdev->dev, "couldn't get telem endpoint %pe", ep);
> d7bc7e19147769 Xi Pardee 2025-06-21  1554  			return -EPROBE_DEFER;
> d7bc7e19147769 Xi Pardee 2025-06-21  1555  		}
> d7bc7e19147769 Xi Pardee 2025-06-21  1556
> f3435ca196060d Xi Pardee 2025-06-21  1557  		if (telem_info & SUB_REQ_LPM)
> d7bc7e19147769 Xi Pardee 2025-06-21  1558  			ret = pmc_core_pmt_get_lpm_req(pmcdev, pmc, ep);
>
> ret is uninitialized on else path.  I generally encourage developers
> to set CONFIG_INIT_STACK_ALL_PATTERN=y for their testing.

Will initialize ret to be 0 in next version. Thanks for your suggestion. 
Will try this option when testing.

Thanks!

Xi

> 78a7491d5cba8b Xi Pardee 2025-04-09 @1559  		if (ret)
> f3435ca196060d Xi Pardee 2025-06-21  1560  			goto unregister_ep;
> f3435ca196060d Xi Pardee 2025-06-21  1561
> f3435ca196060d Xi Pardee 2025-06-21  1562  		if (telem_info & SUB_REQ_BLK)
> f3435ca196060d Xi Pardee 2025-06-21  1563  			ret = pmc_core_pmt_get_blk_sub_req(pmcdev, pmc, ep);
> f3435ca196060d Xi Pardee 2025-06-21  1564  		if (ret)
> f3435ca196060d Xi Pardee 2025-06-21  1565  			goto unregister_ep;
> f3435ca196060d Xi Pardee 2025-06-21  1566
> f3435ca196060d Xi Pardee 2025-06-21  1567  		pmt_telem_unregister_endpoint(ep);
> 78a7491d5cba8b Xi Pardee 2025-04-09  1568  	}
> 78a7491d5cba8b Xi Pardee 2025-04-09  1569
> 78a7491d5cba8b Xi Pardee 2025-04-09  1570  	return 0;
> f3435ca196060d Xi Pardee 2025-06-21  1571
> f3435ca196060d Xi Pardee 2025-06-21  1572  unregister_ep:
> f3435ca196060d Xi Pardee 2025-06-21  1573  	pmt_telem_unregister_endpoint(ep);
> f3435ca196060d Xi Pardee 2025-06-21  1574  	return ret;
> 78a7491d5cba8b Xi Pardee 2025-04-09  1575  }
>

Re: [PATCH v1 4/5] platform/x86:intel/pmc: Show substate requirement for S0ix blockers

[Xi Pardee]

Hi Dan,

Thanks for your comments. Responses are in line.

Xi

On 6/24/2025 7:45 AM, Dan Carpenter wrote:
> Hi Xi,
>
> kernel test robot noticed the following build warnings:
>
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Xi-Pardee/platform-x86-intel-pmc-Enable-SSRAM-support-for-Lunar-Lake/20250622-050804
> base:   linus/master
> patch link:    https://lore.kernel.org/r/20250621210529.237964-5-xi.pardee%40linux.intel.com
> patch subject: [PATCH v1 4/5] platform/x86:intel/pmc: Show substate requirement for S0ix blockers
> config: i386-randconfig-141-20250623 (https://download.01.org/0day-ci/archive/20250624/202506241840.0POVt4tf-lkp@intel.com/config)
> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> | Closes: https://lore.kernel.org/r/202506241840.0POVt4tf-lkp@intel.com/
>
> New smatch warnings:
> drivers/platform/x86/intel/pmc/core.c:1525 pmc_core_pmt_get_blk_sub_req() error: uninitialized symbol 'ret'.
> drivers/platform/x86/intel/pmc/core.c:1559 pmc_core_get_telem_info() error: uninitialized symbol 'ret'.
>
> vim +/ret +1525 drivers/platform/x86/intel/pmc/core.c
>
> f3435ca196060d Xi Pardee 2025-06-21  1497  static int pmc_core_pmt_get_blk_sub_req(struct pmc_dev *pmcdev, struct pmc *pmc,
> f3435ca196060d Xi Pardee 2025-06-21  1498  					struct telem_endpoint *ep)
> f3435ca196060d Xi Pardee 2025-06-21  1499  {
> f3435ca196060d Xi Pardee 2025-06-21  1500  	u32 num_blocker, sample_id;
> f3435ca196060d Xi Pardee 2025-06-21  1501  	unsigned int index;
> f3435ca196060d Xi Pardee 2025-06-21  1502  	u32 *req_offset;
> f3435ca196060d Xi Pardee 2025-06-21  1503  	int ret;
> f3435ca196060d Xi Pardee 2025-06-21  1504
> f3435ca196060d Xi Pardee 2025-06-21  1505  	num_blocker = pmc->map->num_s0ix_blocker;
> f3435ca196060d Xi Pardee 2025-06-21  1506  	sample_id = pmc->map->blocker_req_offset;
> f3435ca196060d Xi Pardee 2025-06-21  1507
> f3435ca196060d Xi Pardee 2025-06-21  1508  	pmc->blk_sub_req_regs = devm_kzalloc(&pmcdev->pdev->dev,
> f3435ca196060d Xi Pardee 2025-06-21  1509  					 num_blocker * sizeof(u32),
>
> Use devm_kcalloc() so we don't have to check if num_blocker can be
> greater than UINT_MAX / 4 on 32bit systems.
>
> f3435ca196060d Xi Pardee 2025-06-21  1510  					 GFP_KERNEL);
> f3435ca196060d Xi Pardee 2025-06-21  1511  	if (!pmc->blk_sub_req_regs)
> f3435ca196060d Xi Pardee 2025-06-21  1512  		ret = -ENOMEM;
>
> s/ret = /return /.  Otherwise it leads to a NULL pointer dereference.
>
> f3435ca196060d Xi Pardee 2025-06-21  1513
> f3435ca196060d Xi Pardee 2025-06-21  1514  	req_offset = pmc->blk_sub_req_regs;
> f3435ca196060d Xi Pardee 2025-06-21  1515  	for (index = 0; index < num_blocker; index++) {
>
> smatch doesn't know if num_blocker can be zero.
To avoid the warning, return 0 instead when function succeeds in version 2.
>
> f3435ca196060d Xi Pardee 2025-06-21  1516  		ret = pmt_telem_read32(ep, sample_id, req_offset, 1);
> f3435ca196060d Xi Pardee 2025-06-21  1517  		if (ret) {
> f3435ca196060d Xi Pardee 2025-06-21  1518  			dev_err(&pmcdev->pdev->dev,
> f3435ca196060d Xi Pardee 2025-06-21  1519  				"couldn't read Low Power Mode requirements: %d\n", ret);
> f3435ca196060d Xi Pardee 2025-06-21  1520  			return ret;
> f3435ca196060d Xi Pardee 2025-06-21  1521  		}
> f3435ca196060d Xi Pardee 2025-06-21  1522  		sample_id++;
> f3435ca196060d Xi Pardee 2025-06-21  1523  		req_offset++;
> f3435ca196060d Xi Pardee 2025-06-21  1524  	}
> f3435ca196060d Xi Pardee 2025-06-21 @1525  	return ret;
> f3435ca196060d Xi Pardee 2025-06-21  1526  }
> f3435ca196060d Xi Pardee 2025-06-21  1527
> f3435ca196060d Xi Pardee 2025-06-21  1528  static int pmc_core_get_telem_info(struct pmc_dev *pmcdev, int func, unsigned int telem_info)
> 78a7491d5cba8b Xi Pardee 2025-04-09  1529  {
> b5d46539626833 Xi Pardee 2025-04-25  1530  	struct pci_dev *pcidev __free(pci_dev_put) = NULL;
> d7bc7e19147769 Xi Pardee 2025-06-21  1531  	struct telem_endpoint *ep;
> 052fabddeaa70b Xi Pardee 2025-04-09  1532  	unsigned int i;
> d7bc7e19147769 Xi Pardee 2025-06-21  1533  	u32 guid;
> 052fabddeaa70b Xi Pardee 2025-04-09  1534  	int ret;
> 78a7491d5cba8b Xi Pardee 2025-04-09  1535
> b5d46539626833 Xi Pardee 2025-04-25  1536  	pcidev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(20, func));
> b5d46539626833 Xi Pardee 2025-04-25  1537  	if (!pcidev)
> 78a7491d5cba8b Xi Pardee 2025-04-09  1538  		return -ENODEV;
> 78a7491d5cba8b Xi Pardee 2025-04-09  1539
> 78a7491d5cba8b Xi Pardee 2025-04-09  1540  	for (i = 0; i < ARRAY_SIZE(pmcdev->pmcs); ++i) {
> d7bc7e19147769 Xi Pardee 2025-06-21  1541  		struct pmc *pmc;
> d7bc7e19147769 Xi Pardee 2025-06-21  1542
> d7bc7e19147769 Xi Pardee 2025-06-21  1543  		pmc = pmcdev->pmcs[i];
> d7bc7e19147769 Xi Pardee 2025-06-21  1544  		if (!pmc)
> 78a7491d5cba8b Xi Pardee 2025-04-09  1545  			continue;
> 78a7491d5cba8b Xi Pardee 2025-04-09  1546
> d7bc7e19147769 Xi Pardee 2025-06-21  1547  		guid = pmc_core_find_guid(pmcdev->regmap_list, pmc->map);
> d7bc7e19147769 Xi Pardee 2025-06-21  1548  		if (!guid)
> d7bc7e19147769 Xi Pardee 2025-06-21  1549  			return -ENXIO;
> d7bc7e19147769 Xi Pardee 2025-06-21  1550
> d7bc7e19147769 Xi Pardee 2025-06-21  1551  		ep = pmt_telem_find_and_register_endpoint(pcidev, guid, 0);
> d7bc7e19147769 Xi Pardee 2025-06-21  1552  		if (IS_ERR(ep)) {
> d7bc7e19147769 Xi Pardee 2025-06-21  1553  			dev_dbg(&pmcdev->pdev->dev, "couldn't get telem endpoint %pe", ep);
> d7bc7e19147769 Xi Pardee 2025-06-21  1554  			return -EPROBE_DEFER;
> d7bc7e19147769 Xi Pardee 2025-06-21  1555  		}
> d7bc7e19147769 Xi Pardee 2025-06-21  1556
> f3435ca196060d Xi Pardee 2025-06-21  1557  		if (telem_info & SUB_REQ_LPM)
> d7bc7e19147769 Xi Pardee 2025-06-21  1558  			ret = pmc_core_pmt_get_lpm_req(pmcdev, pmc, ep);
>
> ret is uninitialized on else path.  I generally encourage developers
> to set CONFIG_INIT_STACK_ALL_PATTERN=y for their testing.
Changed to only check ret value in the if condition in version 2.
> 78a7491d5cba8b Xi Pardee 2025-04-09 @1559  		if (ret)
> f3435ca196060d Xi Pardee 2025-06-21  1560  			goto unregister_ep;
> f3435ca196060d Xi Pardee 2025-06-21  1561
> f3435ca196060d Xi Pardee 2025-06-21  1562  		if (telem_info & SUB_REQ_BLK)
> f3435ca196060d Xi Pardee 2025-06-21  1563  			ret = pmc_core_pmt_get_blk_sub_req(pmcdev, pmc, ep);
> f3435ca196060d Xi Pardee 2025-06-21  1564  		if (ret)
> f3435ca196060d Xi Pardee 2025-06-21  1565  			goto unregister_ep;
> f3435ca196060d Xi Pardee 2025-06-21  1566
> f3435ca196060d Xi Pardee 2025-06-21  1567  		pmt_telem_unregister_endpoint(ep);
> 78a7491d5cba8b Xi Pardee 2025-04-09  1568  	}
> 78a7491d5cba8b Xi Pardee 2025-04-09  1569
> 78a7491d5cba8b Xi Pardee 2025-04-09  1570  	return 0;
> f3435ca196060d Xi Pardee 2025-06-21  1571
> f3435ca196060d Xi Pardee 2025-06-21  1572  unregister_ep:
> f3435ca196060d Xi Pardee 2025-06-21  1573  	pmt_telem_unregister_endpoint(ep);
> f3435ca196060d Xi Pardee 2025-06-21  1574  	return ret;
> 78a7491d5cba8b Xi Pardee 2025-04-09  1575  }
>