[PATCH v4 0/4] Create Intel PMC SSRAM Telemetry driver

[PATCH v4 0/4] Create Intel PMC SSRAM Telemetry driver

[Xi Pardee]

This patch series removes the SSRAM support from Intel PMC Core driver
and creates a separate PCI driver for SSRAM device. The new Intel PMC
SSRAM driver provides the following functionalities:
1. Search and store the PMC information in a structure, including PWRMBASE
address and devid for each available PMC. Then Intel PMC Core driver
achieves the PMC information using the API provided by the new driver.
2. Search and register Intel Platform Monitoring Techology telemetry
regions so they would by available for read through sysfs and Intel PMT
API. Intel PMC Core driver can achieve Low Power Mode requirement
information from a telemetry region registered by the new driver.
 
The above functionalities was previously handled by Intel PMC Core
driver. Intel PMC Core driver returns -EPROBE_DEFER when trying to read
data from a telem region that is not available yet. This setup may
result in an infinite loop of .probe() calls as Intel PMC Core driver
creates child devices. Creating a separate PCI driver avoids the infinite
loop possibility.

V4->v3:
- Remove the first six patches that are accepted.
- Add a patch to change the return type of intel_vsec_registeri() from
  void to int.
- Change the return type of pmc_ssram_telemetry_get_pmc() so the probe
  function of Intel PMC SSRAM Telemetry driver will fail if
  intel_vsec_register() fails. The previous implementation hides the
  failure.
- Use __free(pci_dev_put) in core.c.
- Move pmc_ssram_telemetry_get_pmc_info() function comment to c file
  from h file.
- Add a patch to improve pmc_core_get_lpm_req() suggested by comment
  from last version.

v3->v2:
- Add memory barriers to the new driver to ensure write/read order of
  device_probed variable.
- Minor grammar changes: add needed white space and end of life new line.
- Add patch to move error handling to init function.
- Remove patch to enable SSRAM support of LNL platforms. This patch will be
  included in a separate series.
 
v2->v1:
- Rearrange and restructure patches completely based on feedback from v1

Xi Pardee (4):
  platform/x86:intel/vsec: Change return type of intel_vsec_register
  platform/x86:intel/pmc: Create Intel PMC SSRAM Telemetry driver
  platform/x86:intel/pmc: Move error handling to init function
  platform/x86:intel/pmc: Improve pmc_core_get_lpm_req()

 drivers/platform/x86/intel/pmc/Kconfig        |   4 +
 drivers/platform/x86/intel/pmc/Makefile       |   8 +-
 drivers/platform/x86/intel/pmc/core.c         | 191 +++++++++++-------
 drivers/platform/x86/intel/pmc/core.h         |   7 -
 .../platform/x86/intel/pmc/ssram_telemetry.c  | 147 +++++++++-----
 .../platform/x86/intel/pmc/ssram_telemetry.h  |  24 +++
 drivers/platform/x86/intel/vsec.c             |   9 +-
 include/linux/intel_vsec.h                    |   5 +-
 8 files changed, 261 insertions(+), 134 deletions(-)
 create mode 100644 drivers/platform/x86/intel/pmc/ssram_telemetry.h

-- 
2.43.0

[PATCH v4 1/4] platform/x86:intel/vsec: Change return type of intel_vsec_register

[Xi Pardee]

Change return type of intel_vsec_register() to int. The current
implementation does not indicate if the register fail or not.
Change to return error code if it fails or if INTEL_VSEC config
is not set. This is a preparation step to introduce a new SSRAM
Telemetry driver that will be using this API.

Signed-off-by: Xi Pardee <xi.pardee@linux.intel.com>
---
 drivers/platform/x86/intel/vsec.c | 9 ++++++---
 include/linux/intel_vsec.h        | 5 +++--
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/platform/x86/intel/vsec.c b/drivers/platform/x86/intel/vsec.c
index db3c031d1757..055ca9f48fb4 100644
--- a/drivers/platform/x86/intel/vsec.c
+++ b/drivers/platform/x86/intel/vsec.c
@@ -332,13 +332,16 @@ static bool intel_vsec_walk_vsec(struct pci_dev *pdev,
 	return have_devices;
 }
 
-void intel_vsec_register(struct pci_dev *pdev,
+int intel_vsec_register(struct pci_dev *pdev,
 			 struct intel_vsec_platform_info *info)
 {
 	if (!pdev || !info || !info->headers)
-		return;
+		return -EINVAL;
 
-	intel_vsec_walk_header(pdev, info);
+	if (!intel_vsec_walk_header(pdev, info))
+		return -ENODEV;
+	else
+		return 0;
 }
 EXPORT_SYMBOL_NS_GPL(intel_vsec_register, "INTEL_VSEC");
 
diff --git a/include/linux/intel_vsec.h b/include/linux/intel_vsec.h
index b94beab64610..bc95821f1bfb 100644
--- a/include/linux/intel_vsec.h
+++ b/include/linux/intel_vsec.h
@@ -139,12 +139,13 @@ static inline struct intel_vsec_device *auxdev_to_ivdev(struct auxiliary_device
 }
 
 #if IS_ENABLED(CONFIG_INTEL_VSEC)
-void intel_vsec_register(struct pci_dev *pdev,
+int intel_vsec_register(struct pci_dev *pdev,
 			 struct intel_vsec_platform_info *info);
 #else
-static inline void intel_vsec_register(struct pci_dev *pdev,
+static inline int intel_vsec_register(struct pci_dev *pdev,
 				       struct intel_vsec_platform_info *info)
 {
+	return -ENODEV;
 }
 #endif
 #endif
-- 
2.43.0

[PATCH v4 2/4] platform/x86:intel/pmc: Create Intel PMC SSRAM Telemetry driver

[Xi Pardee]

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>
---
 drivers/platform/x86/intel/pmc/Kconfig        |   4 +
 drivers/platform/x86/intel/pmc/Makefile       |   8 +-
 drivers/platform/x86/intel/pmc/core.c         |  79 +++++++---
 drivers/platform/x86/intel/pmc/core.h         |   7 -
 .../platform/x86/intel/pmc/ssram_telemetry.c  | 147 ++++++++++++------
 .../platform/x86/intel/pmc/ssram_telemetry.h  |  24 +++
 6 files changed, 188 insertions(+), 81 deletions(-)
 create mode 100644 drivers/platform/x86/intel/pmc/ssram_telemetry.h

diff --git a/drivers/platform/x86/intel/pmc/Kconfig b/drivers/platform/x86/intel/pmc/Kconfig
index d2f651fbec2c..c6ef0bcf76af 100644
--- a/drivers/platform/x86/intel/pmc/Kconfig
+++ b/drivers/platform/x86/intel/pmc/Kconfig
@@ -8,6 +8,7 @@ config INTEL_PMC_CORE
 	depends on PCI
 	depends on ACPI
 	depends on INTEL_PMT_TELEMETRY
+	select INTEL_PMC_SSRAM_TELEMETRY
 	help
 	  The Intel Platform Controller Hub for Intel Core SoCs provides access
 	  to Power Management Controller registers via various interfaces. This
@@ -24,3 +25,6 @@ config INTEL_PMC_CORE
 		- SLPS0 Debug registers (Cannonlake/Icelake PCH)
 		- Low Power Mode registers (Tigerlake and beyond)
 		- PMC quirks as needed to enable SLPS0/S0ix
+
+config INTEL_PMC_SSRAM_TELEMETRY
+	tristate
diff --git a/drivers/platform/x86/intel/pmc/Makefile b/drivers/platform/x86/intel/pmc/Makefile
index e842647d3ced..5f68c8503a56 100644
--- a/drivers/platform/x86/intel/pmc/Makefile
+++ b/drivers/platform/x86/intel/pmc/Makefile
@@ -3,8 +3,12 @@
 # Intel x86 Platform-Specific Drivers
 #
 
-intel_pmc_core-y			:= core.o ssram_telemetry.o spt.o cnp.o \
-					   icl.o tgl.o adl.o mtl.o arl.o lnl.o ptl.o
+intel_pmc_core-y			:= core.o spt.o cnp.o icl.o \
+					   tgl.o adl.o mtl.o arl.o lnl.o ptl.o
 obj-$(CONFIG_INTEL_PMC_CORE)		+= intel_pmc_core.o
 intel_pmc_core_pltdrv-y			:= pltdrv.o
 obj-$(CONFIG_INTEL_PMC_CORE)		+= intel_pmc_core_pltdrv.o
+
+# Intel PMC SSRAM driver
+intel_pmc_ssram_telemetry-y		+= ssram_telemetry.o
+obj-$(CONFIG_INTEL_PMC_SSRAM_TELEMETRY)	+= intel_pmc_ssram_telemetry.o
diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
index a53a7677122c..042b60c1185f 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));
@@ -1455,27 +1456,29 @@ static int pmc_core_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc)
 	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;
+	int ret = 0;
 
-	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;
+			break;
 	}
 
-	return 0;
+	return ret;
 }
 
-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;
 
-	if (!pwrm_base)
+	ret = pmc_ssram_telemetry_get_pmc_info(pmc_index, &pmc_ssram_telemetry);
+	if (ret)
+		return ret;
+
+	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);
 
diff --git a/drivers/platform/x86/intel/pmc/core.h b/drivers/platform/x86/intel/pmc/core.h
index c3b07075d017..e136d18b1d38 100644
--- a/drivers/platform/x86/intel/pmc/core.h
+++ b/drivers/platform/x86/intel/pmc/core.h
@@ -413,7 +413,6 @@ struct pmc {
  * struct pmc_dev - pmc device structure
  * @devs:		pointer to an array of pmc pointers
  * @pdev:		pointer to platform_device struct
- * @ssram_pcidev:	pointer to pci device struct for the PMC SSRAM
  * @crystal_freq:	crystal frequency from cpuid
  * @dbgfs_dir:		path to debugfs interface
  * @pmc_xram_read_bit:	flag to indicate whether PMC XRAM shadow registers
@@ -433,7 +432,6 @@ struct pmc_dev {
 	struct pmc *pmcs[MAX_NUM_PMC];
 	struct dentry *dbgfs_dir;
 	struct platform_device *pdev;
-	struct pci_dev *ssram_pcidev;
 	unsigned int crystal_freq;
 	int pmc_xram_read_bit;
 	struct mutex lock; /* generic mutex lock for PMC Core */
@@ -510,12 +508,7 @@ void pmc_core_get_low_power_modes(struct pmc_dev *pmcdev);
 void pmc_core_punit_pmt_init(struct pmc_dev *pmcdev, u32 guid);
 void pmc_core_set_device_d3(unsigned int device);
 
-int pmc_core_ssram_init(struct pmc_dev *pmcdev, int func);
-
 int generic_core_init(struct pmc_dev *pmcdev, struct pmc_dev_info *pmc_dev_info);
-const struct pmc_reg_map *pmc_core_find_regmap(struct pmc_info *list, u16 devid);
-int pmc_core_pmc_add(struct pmc_dev *pmcdev, u64 pwrm_base,
-		     const struct pmc_reg_map *reg_map, unsigned int pmc_index);
 
 extern struct pmc_dev_info spt_pmc_dev;
 extern struct pmc_dev_info cnp_pmc_dev;
diff --git a/drivers/platform/x86/intel/pmc/ssram_telemetry.c b/drivers/platform/x86/intel/pmc/ssram_telemetry.c
index 7b8443092b20..cc2c195f2b74 100644
--- a/drivers/platform/x86/intel/pmc/ssram_telemetry.c
+++ b/drivers/platform/x86/intel/pmc/ssram_telemetry.c
@@ -1,19 +1,18 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * This file contains functions to handle discovery of PMC metrics located
- * in the PMC SSRAM PCI device.
+ * Intel PMC SSRAM TELEMETRY PCI Driver
  *
  * Copyright (c) 2023, Intel Corporation.
- * All Rights Reserved.
- *
  */
 
 #include <linux/cleanup.h>
 #include <linux/intel_vsec.h>
 #include <linux/pci.h>
+#include <linux/types.h>
 #include <linux/io-64-nonatomic-lo-hi.h>
 
 #include "core.h"
+#include "ssram_telemetry.h"
 
 #define SSRAM_HDR_SIZE		0x100
 #define SSRAM_PWRM_OFFSET	0x14
@@ -23,12 +22,14 @@
 #define SSRAM_IOE_OFFSET	0x68
 #define SSRAM_DEVID_OFFSET	0x70
 
-DEFINE_FREE(pmc_core_iounmap, void __iomem *, if (_T) iounmap(_T))
+DEFINE_FREE(pmc_ssram_telemetry_iounmap, void __iomem *, if (_T) iounmap(_T))
+
+static struct pmc_ssram_telemetry *pmc_ssram_telems;
+static bool device_probed;
 
-static void
-pmc_add_pmt(struct pmc_dev *pmcdev, u64 ssram_base, void __iomem *ssram)
+static int
+pmc_ssram_telemetry_add_pmt(struct pci_dev *pcidev, u64 ssram_base, void __iomem *ssram)
 {
-	struct pci_dev *pcidev = pmcdev->ssram_pcidev;
 	struct intel_vsec_platform_info info = {};
 	struct intel_vsec_header *headers[2] = {};
 	struct intel_vsec_header header;
@@ -39,7 +40,7 @@ pmc_add_pmt(struct pmc_dev *pmcdev, u64 ssram_base, void __iomem *ssram)
 	dvsec_offset = readl(ssram + SSRAM_DVSEC_OFFSET);
 	dvsec = ioremap(ssram_base + dvsec_offset, SSRAM_DVSEC_SIZE);
 	if (!dvsec)
-		return;
+		return -ENOMEM;
 
 	hdr = readl(dvsec + PCI_DVSEC_HEADER1);
 	header.id = readw(dvsec + PCI_DVSEC_HEADER2);
@@ -57,9 +58,9 @@ pmc_add_pmt(struct pmc_dev *pmcdev, u64 ssram_base, void __iomem *ssram)
 	info.caps = VSEC_CAP_TELEMETRY;
 	info.headers = headers;
 	info.base_addr = ssram_base;
-	info.parent = &pmcdev->pdev->dev;
+	info.parent = &pcidev->dev;
 
-	intel_vsec_register(pcidev, &info);
+	return intel_vsec_register(pcidev, &info);
 }
 
 static inline u64 get_base(void __iomem *addr, u32 offset)
@@ -68,19 +69,14 @@ static inline u64 get_base(void __iomem *addr, u32 offset)
 }
 
 static int
-pmc_core_ssram_get_pmc(struct pmc_dev *pmcdev, unsigned int pmc_idx, u32 offset)
+pmc_ssram_telemetry_get_pmc(struct pci_dev *pcidev, unsigned int pmc_idx, u32 offset)
 {
-	struct pci_dev *ssram_pcidev = pmcdev->ssram_pcidev;
-	void __iomem __free(pmc_core_iounmap) *tmp_ssram = NULL;
-	void __iomem __free(pmc_core_iounmap) *ssram = NULL;
-	const struct pmc_reg_map *map;
+	void __iomem __free(pmc_ssram_telemetry_iounmap) * tmp_ssram = NULL;
+	void __iomem __free(pmc_ssram_telemetry_iounmap) * ssram = NULL;
 	u64 ssram_base, pwrm_base;
 	u16 devid;
 
-	if (!pmcdev->regmap_list)
-		return -ENOENT;
-
-	ssram_base = ssram_pcidev->resource[0].start;
+	ssram_base = pci_resource_start(pcidev, 0);
 	tmp_ssram = ioremap(ssram_base, SSRAM_HDR_SIZE);
 	if (!tmp_ssram)
 		return -ENOMEM;
@@ -106,46 +102,103 @@ pmc_core_ssram_get_pmc(struct pmc_dev *pmcdev, unsigned int pmc_idx, u32 offset)
 	pwrm_base = get_base(ssram, SSRAM_PWRM_OFFSET);
 	devid = readw(ssram + SSRAM_DEVID_OFFSET);
 
+	pmc_ssram_telems[pmc_idx].devid = devid;
+	pmc_ssram_telems[pmc_idx].base_addr = pwrm_base;
+
 	/* Find and register and PMC telemetry entries */
-	pmc_add_pmt(pmcdev, ssram_base, ssram);
+	return pmc_ssram_telemetry_add_pmt(pcidev, ssram_base, ssram);
+}
 
-	map = pmc_core_find_regmap(pmcdev->regmap_list, devid);
-	if (!map)
+/**
+ * pmc_ssram_telemetry_get_pmc_info() - Get a PMC devid and base_addr information
+ * @pmc_idx:               Index of the PMC
+ * @pmc_ssram_telemetry:   pmc_ssram_telemetry structure to store the PMC information
+ *
+ * Return:
+ * * 0           - Success
+ * * -EAGAIN     - Probe function has not finished yet. Try again.
+ * * -EINVAL     - Invalid pmc_idx
+ * * -ENODEV     - PMC device is not available
+ */
+int pmc_ssram_telemetry_get_pmc_info(unsigned int pmc_idx,
+				     struct pmc_ssram_telemetry *pmc_ssram_telemetry)
+{
+	/*
+	 * PMCs are discovered in probe function. If this function is called before
+	 * probe function complete, the result would be invalid. Use device_probed
+	 * variable to avoid this case. Return -EAGAIN to inform the consumer to call
+	 * again later.
+	 */
+	if (!device_probed)
+		return -EAGAIN;
+
+	/*
+	 * Memory barrier is used to ensure the correct read order between
+	 * device_probed variable and PMC info.
+	 */
+	smp_rmb();
+	if (pmc_idx >= MAX_NUM_PMC)
+		return -EINVAL;
+
+	if (!pmc_ssram_telems || !pmc_ssram_telems[pmc_idx].devid)
 		return -ENODEV;
 
-	return pmc_core_pmc_add(pmcdev, pwrm_base, map, pmc_idx);
+	pmc_ssram_telemetry->devid = pmc_ssram_telems[pmc_idx].devid;
+	pmc_ssram_telemetry->base_addr = pmc_ssram_telems[pmc_idx].base_addr;
+	return 0;
 }
+EXPORT_SYMBOL_GPL(pmc_ssram_telemetry_get_pmc_info);
 
-int pmc_core_ssram_init(struct pmc_dev *pmcdev, int func)
+static int intel_pmc_ssram_telemetry_probe(struct pci_dev *pcidev, const struct pci_device_id *id)
 {
-	struct pci_dev *pcidev;
 	int ret;
 
-	pcidev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(20, func));
-	if (!pcidev)
-		return -ENODEV;
+	pmc_ssram_telems = devm_kzalloc(&pcidev->dev, sizeof(*pmc_ssram_telems) * MAX_NUM_PMC,
+					GFP_KERNEL);
+	if (!pmc_ssram_telems) {
+		ret = -ENOMEM;
+		goto probe_finish;
+	}
 
 	ret = pcim_enable_device(pcidev);
-	if (ret)
-		goto release_dev;
-
-	pmcdev->ssram_pcidev = pcidev;
+	if (ret) {
+		dev_dbg(&pcidev->dev, "failed to enable PMC SSRAM device\n");
+		goto probe_finish;
+	}
 
-	ret = pmc_core_ssram_get_pmc(pmcdev, PMC_IDX_MAIN, 0);
+	ret = pmc_ssram_telemetry_get_pmc(pcidev, PMC_IDX_MAIN, 0);
 	if (ret)
-		goto disable_dev;
-
-	pmc_core_ssram_get_pmc(pmcdev, PMC_IDX_IOE, SSRAM_IOE_OFFSET);
-	pmc_core_ssram_get_pmc(pmcdev, PMC_IDX_PCH, SSRAM_PCH_OFFSET);
-
-	return 0;
-
-disable_dev:
-	pmcdev->ssram_pcidev = NULL;
-	pci_disable_device(pcidev);
-release_dev:
-	pci_dev_put(pcidev);
-
+		goto probe_finish;
+
+	pmc_ssram_telemetry_get_pmc(pcidev, PMC_IDX_IOE, SSRAM_IOE_OFFSET);
+	pmc_ssram_telemetry_get_pmc(pcidev, PMC_IDX_PCH, SSRAM_PCH_OFFSET);
+
+probe_finish:
+	/*
+	 * Memory barrier is used to ensure the correct write order between PMC info
+	 * and device_probed variable.
+	 */
+	smp_wmb();
+	device_probed = true;
 	return ret;
 }
+
+static const struct pci_device_id intel_pmc_ssram_telemetry_pci_ids[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PMC_DEVID_MTL_SOCM) },
+	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PMC_DEVID_ARL_SOCS) },
+	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PMC_DEVID_ARL_SOCM) },
+	{ }
+};
+MODULE_DEVICE_TABLE(pci, intel_pmc_ssram_telemetry_pci_ids);
+
+static struct pci_driver intel_pmc_ssram_telemetry_driver = {
+	.name = "intel_pmc_ssram_telemetry",
+	.id_table = intel_pmc_ssram_telemetry_pci_ids,
+	.probe = intel_pmc_ssram_telemetry_probe,
+};
+module_pci_driver(intel_pmc_ssram_telemetry_driver);
+
 MODULE_IMPORT_NS("INTEL_VSEC");
+MODULE_AUTHOR("Xi Pardee <xi.pardee@intel.com>");
+MODULE_DESCRIPTION("Intel PMC SSRAM Telemetry driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/platform/x86/intel/pmc/ssram_telemetry.h b/drivers/platform/x86/intel/pmc/ssram_telemetry.h
new file mode 100644
index 000000000000..daf8aeeb2275
--- /dev/null
+++ b/drivers/platform/x86/intel/pmc/ssram_telemetry.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Intel PMC SSRAM Telemetry PCI Driver Header File
+ *
+ * Copyright (c) 2024, Intel Corporation.
+ */
+
+#ifndef PMC_SSRAM_H
+#define PMC_SSRAM_H
+
+/**
+ * struct pmc_ssram_telemetry - Structure to keep pmc info in ssram device
+ * @devid:		device id of the pmc device
+ * @base_addr:		contains PWRM base address
+ */
+struct pmc_ssram_telemetry {
+	u16 devid;
+	u64 base_addr;
+};
+
+int pmc_ssram_telemetry_get_pmc_info(unsigned int pmc_idx,
+				     struct pmc_ssram_telemetry *pmc_ssram_telemetry);
+
+#endif /* PMC_SSRAM_H */
-- 
2.43.0

[PATCH v4 3/4] platform/x86:intel/pmc: Move error handling to init function

[Xi Pardee]

Move error handling code to generic_core_init() function. The previous
implementation is that init function called for "full cleanup" function
when error occurs which is error prone. The init function should handle
the error path itself to improve code maintainability.

Signed-off-by: Xi Pardee <xi.pardee@linux.intel.com>
---
 drivers/platform/x86/intel/pmc/core.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
index 042b60c1185f..e09a97564398 100644
--- a/drivers/platform/x86/intel/pmc/core.c
+++ b/drivers/platform/x86/intel/pmc/core.c
@@ -1583,10 +1583,26 @@ int generic_core_init(struct pmc_dev *pmcdev, struct pmc_dev_info *pmc_dev_info)
 	if (pmc_dev_info->dmu_guid)
 		pmc_core_punit_pmt_init(pmcdev, pmc_dev_info->dmu_guid);
 
-	if (ssram)
-		return pmc_core_ssram_get_lpm_reqs(pmcdev, pmc_dev_info->pci_func);
+	if (ssram) {
+		ret = pmc_core_ssram_get_lpm_reqs(pmcdev, pmc_dev_info->pci_func);
+		if (ret)
+			goto unmap_regbase;
+	}
 
 	return 0;
+
+unmap_regbase:
+	for (unsigned int i = 0; i < ARRAY_SIZE(pmcdev->pmcs); ++i) {
+		struct pmc *pmc = pmcdev->pmcs[i];
+
+		if (pmc && pmc->regbase)
+			iounmap(pmc->regbase);
+	}
+
+	if (pmcdev->punit_ep)
+		pmt_telem_unregister_endpoint(pmcdev->punit_ep);
+
+	return ret;
 }
 
 static const struct x86_cpu_id intel_pmc_core_ids[] = {
@@ -1734,7 +1750,8 @@ static int pmc_core_probe(struct platform_device *pdev)
 		ret = generic_core_init(pmcdev, pmc_dev_info);
 
 	if (ret) {
-		pmc_core_clean_structure(pdev);
+		platform_set_drvdata(pdev, NULL);
+		mutex_destroy(&pmcdev->lock);
 		return ret;
 	}
 
-- 
2.43.0

[PATCH v4 4/4] platform/x86:intel/pmc: Improve pmc_core_get_lpm_req()

[Xi Pardee]

Minor improvements on pmc_core_get_lpm_req().
1. Move the long comment to be above the function
2. Use %pe to print error pointer
3. Remove unneeded devm_kfree call

These changes improves the code maintainability.

Signed-off-by: Xi Pardee <xi.pardee@linux.intel.com>
---
 drivers/platform/x86/intel/pmc/core.c | 91 +++++++++++++--------------
 1 file changed, 45 insertions(+), 46 deletions(-)

diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
index e09a97564398..6f092b00b030 100644
--- a/drivers/platform/x86/intel/pmc/core.c
+++ b/drivers/platform/x86/intel/pmc/core.c
@@ -1355,6 +1355,50 @@ static u32 pmc_core_find_guid(struct pmc_info *list, const struct pmc_reg_map *m
 	return 0;
 }
 
+/*
+ * This function retrieves low power mode requirement data from 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                          |
+ * +----+---------------------------------------------------------+
+ *
+ */
 static int pmc_core_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc, struct pci_dev *pcidev)
 {
 	struct telem_endpoint *ep;
@@ -1374,8 +1418,7 @@ static int pmc_core_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc, struct
 
 	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));
+		dev_dbg(&pmcdev->pdev->dev, "couldn't get telem endpoint %pe", ep);
 		return -EPROBE_DEFER;
 	}
 
@@ -1387,49 +1430,6 @@ static int pmc_core_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc, struct
 		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(mode, pmcdev) {
 		u32 *req_offset = pmc->lpm_req_regs + (mode * num_maps);
@@ -1442,7 +1442,6 @@ 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);
-				devm_kfree(&pmcdev->pdev->dev, pmc->lpm_req_regs);
 				goto unregister_ep;
 			}
 			++req_offset;
-- 
2.43.0

Re: [PATCH v4 2/4] platform/x86:intel/pmc: Create Intel PMC SSRAM Telemetry driver

[Ilpo Järvinen]

On Mon, 21 Apr 2025, Xi Pardee wrote:

> 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>
> ---
>  drivers/platform/x86/intel/pmc/Kconfig        |   4 +
>  drivers/platform/x86/intel/pmc/Makefile       |   8 +-
>  drivers/platform/x86/intel/pmc/core.c         |  79 +++++++---
>  drivers/platform/x86/intel/pmc/core.h         |   7 -
>  .../platform/x86/intel/pmc/ssram_telemetry.c  | 147 ++++++++++++------
>  .../platform/x86/intel/pmc/ssram_telemetry.h  |  24 +++
>  6 files changed, 188 insertions(+), 81 deletions(-)
>  create mode 100644 drivers/platform/x86/intel/pmc/ssram_telemetry.h
> 
> diff --git a/drivers/platform/x86/intel/pmc/Kconfig b/drivers/platform/x86/intel/pmc/Kconfig
> index d2f651fbec2c..c6ef0bcf76af 100644
> --- a/drivers/platform/x86/intel/pmc/Kconfig
> +++ b/drivers/platform/x86/intel/pmc/Kconfig
> @@ -8,6 +8,7 @@ config INTEL_PMC_CORE
>  	depends on PCI
>  	depends on ACPI
>  	depends on INTEL_PMT_TELEMETRY
> +	select INTEL_PMC_SSRAM_TELEMETRY
>  	help
>  	  The Intel Platform Controller Hub for Intel Core SoCs provides access
>  	  to Power Management Controller registers via various interfaces. This
> @@ -24,3 +25,6 @@ config INTEL_PMC_CORE
>  		- SLPS0 Debug registers (Cannonlake/Icelake PCH)
>  		- Low Power Mode registers (Tigerlake and beyond)
>  		- PMC quirks as needed to enable SLPS0/S0ix
> +
> +config INTEL_PMC_SSRAM_TELEMETRY
> +	tristate
> diff --git a/drivers/platform/x86/intel/pmc/Makefile b/drivers/platform/x86/intel/pmc/Makefile
> index e842647d3ced..5f68c8503a56 100644
> --- a/drivers/platform/x86/intel/pmc/Makefile
> +++ b/drivers/platform/x86/intel/pmc/Makefile
> @@ -3,8 +3,12 @@
>  # Intel x86 Platform-Specific Drivers
>  #
>  
> -intel_pmc_core-y			:= core.o ssram_telemetry.o spt.o cnp.o \
> -					   icl.o tgl.o adl.o mtl.o arl.o lnl.o ptl.o
> +intel_pmc_core-y			:= core.o spt.o cnp.o icl.o \
> +					   tgl.o adl.o mtl.o arl.o lnl.o ptl.o
>  obj-$(CONFIG_INTEL_PMC_CORE)		+= intel_pmc_core.o
>  intel_pmc_core_pltdrv-y			:= pltdrv.o
>  obj-$(CONFIG_INTEL_PMC_CORE)		+= intel_pmc_core_pltdrv.o
> +
> +# Intel PMC SSRAM driver
> +intel_pmc_ssram_telemetry-y		+= ssram_telemetry.o
> +obj-$(CONFIG_INTEL_PMC_SSRAM_TELEMETRY)	+= intel_pmc_ssram_telemetry.o
> diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
> index a53a7677122c..042b60c1185f 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));
> @@ -1455,27 +1456,29 @@ static int pmc_core_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc)
>  	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;
> +	int ret = 0;

After you remove the return changes below, this change is not needed 
either.

>  
> -	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;
> +			break;

These two return changes are unnecessary.

>  	}
>  
> -	return 0;
> +	return ret;

-- 
 i.

>  }
>  
> -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;
>  
> -	if (!pwrm_base)
> +	ret = pmc_ssram_telemetry_get_pmc_info(pmc_index, &pmc_ssram_telemetry);
> +	if (ret)
> +		return ret;
> +
> +	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);
>  
> diff --git a/drivers/platform/x86/intel/pmc/core.h b/drivers/platform/x86/intel/pmc/core.h
> index c3b07075d017..e136d18b1d38 100644
> --- a/drivers/platform/x86/intel/pmc/core.h
> +++ b/drivers/platform/x86/intel/pmc/core.h
> @@ -413,7 +413,6 @@ struct pmc {
>   * struct pmc_dev - pmc device structure
>   * @devs:		pointer to an array of pmc pointers
>   * @pdev:		pointer to platform_device struct
> - * @ssram_pcidev:	pointer to pci device struct for the PMC SSRAM
>   * @crystal_freq:	crystal frequency from cpuid
>   * @dbgfs_dir:		path to debugfs interface
>   * @pmc_xram_read_bit:	flag to indicate whether PMC XRAM shadow registers
> @@ -433,7 +432,6 @@ struct pmc_dev {
>  	struct pmc *pmcs[MAX_NUM_PMC];
>  	struct dentry *dbgfs_dir;
>  	struct platform_device *pdev;
> -	struct pci_dev *ssram_pcidev;
>  	unsigned int crystal_freq;
>  	int pmc_xram_read_bit;
>  	struct mutex lock; /* generic mutex lock for PMC Core */
> @@ -510,12 +508,7 @@ void pmc_core_get_low_power_modes(struct pmc_dev *pmcdev);
>  void pmc_core_punit_pmt_init(struct pmc_dev *pmcdev, u32 guid);
>  void pmc_core_set_device_d3(unsigned int device);
>  
> -int pmc_core_ssram_init(struct pmc_dev *pmcdev, int func);
> -
>  int generic_core_init(struct pmc_dev *pmcdev, struct pmc_dev_info *pmc_dev_info);
> -const struct pmc_reg_map *pmc_core_find_regmap(struct pmc_info *list, u16 devid);
> -int pmc_core_pmc_add(struct pmc_dev *pmcdev, u64 pwrm_base,
> -		     const struct pmc_reg_map *reg_map, unsigned int pmc_index);
>  
>  extern struct pmc_dev_info spt_pmc_dev;
>  extern struct pmc_dev_info cnp_pmc_dev;
> diff --git a/drivers/platform/x86/intel/pmc/ssram_telemetry.c b/drivers/platform/x86/intel/pmc/ssram_telemetry.c
> index 7b8443092b20..cc2c195f2b74 100644
> --- a/drivers/platform/x86/intel/pmc/ssram_telemetry.c
> +++ b/drivers/platform/x86/intel/pmc/ssram_telemetry.c
> @@ -1,19 +1,18 @@
>  // SPDX-License-Identifier: GPL-2.0
>  /*
> - * This file contains functions to handle discovery of PMC metrics located
> - * in the PMC SSRAM PCI device.
> + * Intel PMC SSRAM TELEMETRY PCI Driver
>   *
>   * Copyright (c) 2023, Intel Corporation.
> - * All Rights Reserved.
> - *
>   */
>  
>  #include <linux/cleanup.h>
>  #include <linux/intel_vsec.h>
>  #include <linux/pci.h>
> +#include <linux/types.h>
>  #include <linux/io-64-nonatomic-lo-hi.h>
>  
>  #include "core.h"
> +#include "ssram_telemetry.h"
>  
>  #define SSRAM_HDR_SIZE		0x100
>  #define SSRAM_PWRM_OFFSET	0x14
> @@ -23,12 +22,14 @@
>  #define SSRAM_IOE_OFFSET	0x68
>  #define SSRAM_DEVID_OFFSET	0x70
>  
> -DEFINE_FREE(pmc_core_iounmap, void __iomem *, if (_T) iounmap(_T))
> +DEFINE_FREE(pmc_ssram_telemetry_iounmap, void __iomem *, if (_T) iounmap(_T))
> +
> +static struct pmc_ssram_telemetry *pmc_ssram_telems;
> +static bool device_probed;
>  
> -static void
> -pmc_add_pmt(struct pmc_dev *pmcdev, u64 ssram_base, void __iomem *ssram)
> +static int
> +pmc_ssram_telemetry_add_pmt(struct pci_dev *pcidev, u64 ssram_base, void __iomem *ssram)
>  {
> -	struct pci_dev *pcidev = pmcdev->ssram_pcidev;
>  	struct intel_vsec_platform_info info = {};
>  	struct intel_vsec_header *headers[2] = {};
>  	struct intel_vsec_header header;
> @@ -39,7 +40,7 @@ pmc_add_pmt(struct pmc_dev *pmcdev, u64 ssram_base, void __iomem *ssram)
>  	dvsec_offset = readl(ssram + SSRAM_DVSEC_OFFSET);
>  	dvsec = ioremap(ssram_base + dvsec_offset, SSRAM_DVSEC_SIZE);
>  	if (!dvsec)
> -		return;
> +		return -ENOMEM;
>  
>  	hdr = readl(dvsec + PCI_DVSEC_HEADER1);
>  	header.id = readw(dvsec + PCI_DVSEC_HEADER2);
> @@ -57,9 +58,9 @@ pmc_add_pmt(struct pmc_dev *pmcdev, u64 ssram_base, void __iomem *ssram)
>  	info.caps = VSEC_CAP_TELEMETRY;
>  	info.headers = headers;
>  	info.base_addr = ssram_base;
> -	info.parent = &pmcdev->pdev->dev;
> +	info.parent = &pcidev->dev;
>  
> -	intel_vsec_register(pcidev, &info);
> +	return intel_vsec_register(pcidev, &info);
>  }
>  
>  static inline u64 get_base(void __iomem *addr, u32 offset)
> @@ -68,19 +69,14 @@ static inline u64 get_base(void __iomem *addr, u32 offset)
>  }
>  
>  static int
> -pmc_core_ssram_get_pmc(struct pmc_dev *pmcdev, unsigned int pmc_idx, u32 offset)
> +pmc_ssram_telemetry_get_pmc(struct pci_dev *pcidev, unsigned int pmc_idx, u32 offset)
>  {
> -	struct pci_dev *ssram_pcidev = pmcdev->ssram_pcidev;
> -	void __iomem __free(pmc_core_iounmap) *tmp_ssram = NULL;
> -	void __iomem __free(pmc_core_iounmap) *ssram = NULL;
> -	const struct pmc_reg_map *map;
> +	void __iomem __free(pmc_ssram_telemetry_iounmap) * tmp_ssram = NULL;
> +	void __iomem __free(pmc_ssram_telemetry_iounmap) * ssram = NULL;
>  	u64 ssram_base, pwrm_base;
>  	u16 devid;
>  
> -	if (!pmcdev->regmap_list)
> -		return -ENOENT;
> -
> -	ssram_base = ssram_pcidev->resource[0].start;
> +	ssram_base = pci_resource_start(pcidev, 0);
>  	tmp_ssram = ioremap(ssram_base, SSRAM_HDR_SIZE);
>  	if (!tmp_ssram)
>  		return -ENOMEM;
> @@ -106,46 +102,103 @@ pmc_core_ssram_get_pmc(struct pmc_dev *pmcdev, unsigned int pmc_idx, u32 offset)
>  	pwrm_base = get_base(ssram, SSRAM_PWRM_OFFSET);
>  	devid = readw(ssram + SSRAM_DEVID_OFFSET);
>  
> +	pmc_ssram_telems[pmc_idx].devid = devid;
> +	pmc_ssram_telems[pmc_idx].base_addr = pwrm_base;
> +
>  	/* Find and register and PMC telemetry entries */
> -	pmc_add_pmt(pmcdev, ssram_base, ssram);
> +	return pmc_ssram_telemetry_add_pmt(pcidev, ssram_base, ssram);
> +}
>  
> -	map = pmc_core_find_regmap(pmcdev->regmap_list, devid);
> -	if (!map)
> +/**
> + * pmc_ssram_telemetry_get_pmc_info() - Get a PMC devid and base_addr information
> + * @pmc_idx:               Index of the PMC
> + * @pmc_ssram_telemetry:   pmc_ssram_telemetry structure to store the PMC information
> + *
> + * Return:
> + * * 0           - Success
> + * * -EAGAIN     - Probe function has not finished yet. Try again.
> + * * -EINVAL     - Invalid pmc_idx
> + * * -ENODEV     - PMC device is not available
> + */
> +int pmc_ssram_telemetry_get_pmc_info(unsigned int pmc_idx,
> +				     struct pmc_ssram_telemetry *pmc_ssram_telemetry)
> +{
> +	/*
> +	 * PMCs are discovered in probe function. If this function is called before
> +	 * probe function complete, the result would be invalid. Use device_probed
> +	 * variable to avoid this case. Return -EAGAIN to inform the consumer to call
> +	 * again later.
> +	 */
> +	if (!device_probed)
> +		return -EAGAIN;
> +
> +	/*
> +	 * Memory barrier is used to ensure the correct read order between
> +	 * device_probed variable and PMC info.
> +	 */
> +	smp_rmb();
> +	if (pmc_idx >= MAX_NUM_PMC)
> +		return -EINVAL;
> +
> +	if (!pmc_ssram_telems || !pmc_ssram_telems[pmc_idx].devid)
>  		return -ENODEV;
>  
> -	return pmc_core_pmc_add(pmcdev, pwrm_base, map, pmc_idx);
> +	pmc_ssram_telemetry->devid = pmc_ssram_telems[pmc_idx].devid;
> +	pmc_ssram_telemetry->base_addr = pmc_ssram_telems[pmc_idx].base_addr;
> +	return 0;
>  }
> +EXPORT_SYMBOL_GPL(pmc_ssram_telemetry_get_pmc_info);
>  
> -int pmc_core_ssram_init(struct pmc_dev *pmcdev, int func)
> +static int intel_pmc_ssram_telemetry_probe(struct pci_dev *pcidev, const struct pci_device_id *id)
>  {
> -	struct pci_dev *pcidev;
>  	int ret;
>  
> -	pcidev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(20, func));
> -	if (!pcidev)
> -		return -ENODEV;
> +	pmc_ssram_telems = devm_kzalloc(&pcidev->dev, sizeof(*pmc_ssram_telems) * MAX_NUM_PMC,
> +					GFP_KERNEL);
> +	if (!pmc_ssram_telems) {
> +		ret = -ENOMEM;
> +		goto probe_finish;
> +	}
>  
>  	ret = pcim_enable_device(pcidev);
> -	if (ret)
> -		goto release_dev;
> -
> -	pmcdev->ssram_pcidev = pcidev;
> +	if (ret) {
> +		dev_dbg(&pcidev->dev, "failed to enable PMC SSRAM device\n");
> +		goto probe_finish;
> +	}
>  
> -	ret = pmc_core_ssram_get_pmc(pmcdev, PMC_IDX_MAIN, 0);
> +	ret = pmc_ssram_telemetry_get_pmc(pcidev, PMC_IDX_MAIN, 0);
>  	if (ret)
> -		goto disable_dev;
> -
> -	pmc_core_ssram_get_pmc(pmcdev, PMC_IDX_IOE, SSRAM_IOE_OFFSET);
> -	pmc_core_ssram_get_pmc(pmcdev, PMC_IDX_PCH, SSRAM_PCH_OFFSET);
> -
> -	return 0;
> -
> -disable_dev:
> -	pmcdev->ssram_pcidev = NULL;
> -	pci_disable_device(pcidev);
> -release_dev:
> -	pci_dev_put(pcidev);
> -
> +		goto probe_finish;
> +
> +	pmc_ssram_telemetry_get_pmc(pcidev, PMC_IDX_IOE, SSRAM_IOE_OFFSET);
> +	pmc_ssram_telemetry_get_pmc(pcidev, PMC_IDX_PCH, SSRAM_PCH_OFFSET);
> +
> +probe_finish:
> +	/*
> +	 * Memory barrier is used to ensure the correct write order between PMC info
> +	 * and device_probed variable.
> +	 */
> +	smp_wmb();
> +	device_probed = true;
>  	return ret;
>  }
> +
> +static const struct pci_device_id intel_pmc_ssram_telemetry_pci_ids[] = {
> +	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PMC_DEVID_MTL_SOCM) },
> +	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PMC_DEVID_ARL_SOCS) },
> +	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PMC_DEVID_ARL_SOCM) },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(pci, intel_pmc_ssram_telemetry_pci_ids);
> +
> +static struct pci_driver intel_pmc_ssram_telemetry_driver = {
> +	.name = "intel_pmc_ssram_telemetry",
> +	.id_table = intel_pmc_ssram_telemetry_pci_ids,
> +	.probe = intel_pmc_ssram_telemetry_probe,
> +};
> +module_pci_driver(intel_pmc_ssram_telemetry_driver);
> +
>  MODULE_IMPORT_NS("INTEL_VSEC");
> +MODULE_AUTHOR("Xi Pardee <xi.pardee@intel.com>");
> +MODULE_DESCRIPTION("Intel PMC SSRAM Telemetry driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/platform/x86/intel/pmc/ssram_telemetry.h b/drivers/platform/x86/intel/pmc/ssram_telemetry.h
> new file mode 100644
> index 000000000000..daf8aeeb2275
> --- /dev/null
> +++ b/drivers/platform/x86/intel/pmc/ssram_telemetry.h
> @@ -0,0 +1,24 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Intel PMC SSRAM Telemetry PCI Driver Header File
> + *
> + * Copyright (c) 2024, Intel Corporation.
> + */
> +
> +#ifndef PMC_SSRAM_H
> +#define PMC_SSRAM_H
> +
> +/**
> + * struct pmc_ssram_telemetry - Structure to keep pmc info in ssram device
> + * @devid:		device id of the pmc device
> + * @base_addr:		contains PWRM base address
> + */
> +struct pmc_ssram_telemetry {
> +	u16 devid;
> +	u64 base_addr;
> +};
> +
> +int pmc_ssram_telemetry_get_pmc_info(unsigned int pmc_idx,
> +				     struct pmc_ssram_telemetry *pmc_ssram_telemetry);
> +
> +#endif /* PMC_SSRAM_H */
> 

Re: [PATCH v4 3/4] platform/x86:intel/pmc: Move error handling to init function

[Ilpo Järvinen]

On Mon, 21 Apr 2025, Xi Pardee wrote:

> Move error handling code to generic_core_init() function. The previous
> implementation is that init function called for "full cleanup" function
> when error occurs which is error prone. The init function should handle
> the error path itself to improve code maintainability.
> 
> Signed-off-by: Xi Pardee <xi.pardee@linux.intel.com>
> ---
>  drivers/platform/x86/intel/pmc/core.c | 23 ++++++++++++++++++++---
>  1 file changed, 20 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
> index 042b60c1185f..e09a97564398 100644
> --- a/drivers/platform/x86/intel/pmc/core.c
> +++ b/drivers/platform/x86/intel/pmc/core.c
> @@ -1583,10 +1583,26 @@ int generic_core_init(struct pmc_dev *pmcdev, struct pmc_dev_info *pmc_dev_info)
>  	if (pmc_dev_info->dmu_guid)
>  		pmc_core_punit_pmt_init(pmcdev, pmc_dev_info->dmu_guid);
>  
> -	if (ssram)
> -		return pmc_core_ssram_get_lpm_reqs(pmcdev, pmc_dev_info->pci_func);
> +	if (ssram) {
> +		ret = pmc_core_ssram_get_lpm_reqs(pmcdev, pmc_dev_info->pci_func);
> +		if (ret)
> +			goto unmap_regbase;
> +	}
>  
>  	return 0;
> +
> +unmap_regbase:
> +	for (unsigned int i = 0; i < ARRAY_SIZE(pmcdev->pmcs); ++i) {
> +		struct pmc *pmc = pmcdev->pmcs[i];
> +
> +		if (pmc && pmc->regbase)
> +			iounmap(pmc->regbase);
> +	}
> +
> +	if (pmcdev->punit_ep)
> +		pmt_telem_unregister_endpoint(pmcdev->punit_ep);
> +
> +	return ret;
>  }
>  
>  static const struct x86_cpu_id intel_pmc_core_ids[] = {
> @@ -1734,7 +1750,8 @@ static int pmc_core_probe(struct platform_device *pdev)
>  		ret = generic_core_init(pmcdev, pmc_dev_info);
>  
>  	if (ret) {
> -		pmc_core_clean_structure(pdev);
> +		platform_set_drvdata(pdev, NULL);
> +		mutex_destroy(&pmcdev->lock);

Please change also the mutex init to use devm_mutex_init(), don't forget 
to include error handling for it as it devm_mutex_init() can fail.

>  		return ret;
>  	}
>  
> 

-- 
 i.

Re: [PATCH v4 2/4] platform/x86:intel/pmc: Create Intel PMC SSRAM Telemetry driver

[Xi Pardee]

On 4/24/2025 7:01 AM, Ilpo Järvinen wrote:
> On Mon, 21 Apr 2025, Xi Pardee wrote:
>
>> 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>
>> ---
>>   drivers/platform/x86/intel/pmc/Kconfig        |   4 +
>>   drivers/platform/x86/intel/pmc/Makefile       |   8 +-
>>   drivers/platform/x86/intel/pmc/core.c         |  79 +++++++---
>>   drivers/platform/x86/intel/pmc/core.h         |   7 -
>>   .../platform/x86/intel/pmc/ssram_telemetry.c  | 147 ++++++++++++------
>>   .../platform/x86/intel/pmc/ssram_telemetry.h  |  24 +++
>>   6 files changed, 188 insertions(+), 81 deletions(-)
>>   create mode 100644 drivers/platform/x86/intel/pmc/ssram_telemetry.h
>>
>> diff --git a/drivers/platform/x86/intel/pmc/Kconfig b/drivers/platform/x86/intel/pmc/Kconfig
>> index d2f651fbec2c..c6ef0bcf76af 100644
>> --- a/drivers/platform/x86/intel/pmc/Kconfig
>> +++ b/drivers/platform/x86/intel/pmc/Kconfig
>> @@ -8,6 +8,7 @@ config INTEL_PMC_CORE
>>   	depends on PCI
>>   	depends on ACPI
>>   	depends on INTEL_PMT_TELEMETRY
>> +	select INTEL_PMC_SSRAM_TELEMETRY
>>   	help
>>   	  The Intel Platform Controller Hub for Intel Core SoCs provides access
>>   	  to Power Management Controller registers via various interfaces. This
>> @@ -24,3 +25,6 @@ config INTEL_PMC_CORE
>>   		- SLPS0 Debug registers (Cannonlake/Icelake PCH)
>>   		- Low Power Mode registers (Tigerlake and beyond)
>>   		- PMC quirks as needed to enable SLPS0/S0ix
>> +
>> +config INTEL_PMC_SSRAM_TELEMETRY
>> +	tristate
>> diff --git a/drivers/platform/x86/intel/pmc/Makefile b/drivers/platform/x86/intel/pmc/Makefile
>> index e842647d3ced..5f68c8503a56 100644
>> --- a/drivers/platform/x86/intel/pmc/Makefile
>> +++ b/drivers/platform/x86/intel/pmc/Makefile
>> @@ -3,8 +3,12 @@
>>   # Intel x86 Platform-Specific Drivers
>>   #
>>   
>> -intel_pmc_core-y			:= core.o ssram_telemetry.o spt.o cnp.o \
>> -					   icl.o tgl.o adl.o mtl.o arl.o lnl.o ptl.o
>> +intel_pmc_core-y			:= core.o spt.o cnp.o icl.o \
>> +					   tgl.o adl.o mtl.o arl.o lnl.o ptl.o
>>   obj-$(CONFIG_INTEL_PMC_CORE)		+= intel_pmc_core.o
>>   intel_pmc_core_pltdrv-y			:= pltdrv.o
>>   obj-$(CONFIG_INTEL_PMC_CORE)		+= intel_pmc_core_pltdrv.o
>> +
>> +# Intel PMC SSRAM driver
>> +intel_pmc_ssram_telemetry-y		+= ssram_telemetry.o
>> +obj-$(CONFIG_INTEL_PMC_SSRAM_TELEMETRY)	+= intel_pmc_ssram_telemetry.o
>> diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
>> index a53a7677122c..042b60c1185f 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));
>> @@ -1455,27 +1456,29 @@ static int pmc_core_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc)
>>   	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;
>> +	int ret = 0;
> After you remove the return changes below, this change is not needed
> either.
>
>>   
>> -	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;
>> +			break;
> These two return changes are unnecessary.

Thanks for the comments.

Will remove these return changes in next version.

Xi

>>   	}
>>   
>> -	return 0;
>> +	return ret;

Re: [PATCH v4 3/4] platform/x86:intel/pmc: Move error handling to init function

[Xi Pardee]

On 4/24/2025 7:02 AM, Ilpo Järvinen wrote:
> On Mon, 21 Apr 2025, Xi Pardee wrote:
>
>> Move error handling code to generic_core_init() function. The previous
>> implementation is that init function called for "full cleanup" function
>> when error occurs which is error prone. The init function should handle
>> the error path itself to improve code maintainability.
>>
>> Signed-off-by: Xi Pardee <xi.pardee@linux.intel.com>
>> ---
>>   drivers/platform/x86/intel/pmc/core.c | 23 ++++++++++++++++++++---
>>   1 file changed, 20 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
>> index 042b60c1185f..e09a97564398 100644
>> --- a/drivers/platform/x86/intel/pmc/core.c
>> +++ b/drivers/platform/x86/intel/pmc/core.c
>> @@ -1583,10 +1583,26 @@ int generic_core_init(struct pmc_dev *pmcdev, struct pmc_dev_info *pmc_dev_info)
>>   	if (pmc_dev_info->dmu_guid)
>>   		pmc_core_punit_pmt_init(pmcdev, pmc_dev_info->dmu_guid);
>>   
>> -	if (ssram)
>> -		return pmc_core_ssram_get_lpm_reqs(pmcdev, pmc_dev_info->pci_func);
>> +	if (ssram) {
>> +		ret = pmc_core_ssram_get_lpm_reqs(pmcdev, pmc_dev_info->pci_func);
>> +		if (ret)
>> +			goto unmap_regbase;
>> +	}
>>   
>>   	return 0;
>> +
>> +unmap_regbase:
>> +	for (unsigned int i = 0; i < ARRAY_SIZE(pmcdev->pmcs); ++i) {
>> +		struct pmc *pmc = pmcdev->pmcs[i];
>> +
>> +		if (pmc && pmc->regbase)
>> +			iounmap(pmc->regbase);
>> +	}
>> +
>> +	if (pmcdev->punit_ep)
>> +		pmt_telem_unregister_endpoint(pmcdev->punit_ep);
>> +
>> +	return ret;
>>   }
>>   
>>   static const struct x86_cpu_id intel_pmc_core_ids[] = {
>> @@ -1734,7 +1750,8 @@ static int pmc_core_probe(struct platform_device *pdev)
>>   		ret = generic_core_init(pmcdev, pmc_dev_info);
>>   
>>   	if (ret) {
>> -		pmc_core_clean_structure(pdev);
>> +		platform_set_drvdata(pdev, NULL);
>> +		mutex_destroy(&pmcdev->lock);
> Please change also the mutex init to use devm_mutex_init(), don't forget
> to include error handling for it as it devm_mutex_init() can fail.

Will change to devm_mutex_init() in next version.

Thanks!

Xi

>>   		return ret;
>>   	}
>>   
>>