platform/x86/intel/pmc: Cleanup SSRAM discovery

Clean up the code handling SSRAM discovery. Handle all resource allocation
and cleanup in pmc_core_ssram_get_pmc(). Return the error status from this
function but only fail the init if we fail to discover the primary PMC.

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20231129222132.2331261-14-david.e.box@linux.intel.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Author: debox1

drivers/platform/x86/intel/pmc/core_ssram.c

@@ -8,6 +8,7 @@
  *
  */
 
+#include <linux/cleanup.h>
 #include <linux/pci.h>
 #include <linux/io-64-nonatomic-lo-hi.h>
 
@@ -21,6 +22,8 @@
 #define SSRAM_IOE_OFFSET	0x68
 #define SSRAM_DEVID_OFFSET	0x70
 
+DEFINE_FREE(pmc_core_iounmap, void __iomem *, iounmap(_T));
+
 static const struct pmc_reg_map *pmc_core_find_regmap(struct pmc_info *list, u16 devid)
 {
 	for (; list->map; ++list)
@@ -65,44 +68,49 @@ pmc_core_pmc_add(struct pmc_dev *pmcdev, u64 pwrm_base,
 	return 0;
 }
 
-static void
-pmc_core_ssram_get_pmc(struct pmc_dev *pmcdev, void __iomem *ssram, u32 offset,
-		       int pmc_idx)
+static int
+pmc_core_ssram_get_pmc(struct pmc_dev *pmcdev, int pmc_idx, u32 offset)
 {
-	u64 pwrm_base;
+	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;
+	u64 ssram_base, pwrm_base;
 	u16 devid;
 
-	if (pmc_idx != PMC_IDX_SOC) {
-		u64 ssram_base = get_base(ssram, offset);
+	if (!pmcdev->regmap_list)
+		return -ENOENT;
 
-		if (!ssram_base)
-			return;
+	ssram_base = ssram_pcidev->resource[0].start;
+	tmp_ssram = ioremap(ssram_base, SSRAM_HDR_SIZE);
 
+	if (pmc_idx != PMC_IDX_MAIN) {
+		/*
+		 * The secondary PMC BARS (which are behind hidden PCI devices)
+		 * are read from fixed offsets in MMIO of the primary PMC BAR.
+		 */
+		ssram_base = get_base(tmp_ssram, offset);
 		ssram = ioremap(ssram_base, SSRAM_HDR_SIZE);
 		if (!ssram)
-			return;
+			return -ENOMEM;
+
+	} else {
+		ssram = no_free_ptr(tmp_ssram);
 	}
 
 	pwrm_base = get_base(ssram, SSRAM_PWRM_OFFSET);
 	devid = readw(ssram + SSRAM_DEVID_OFFSET);
 
-	if (pmcdev->regmap_list) {
-		const struct pmc_reg_map *map;
-
-		map = pmc_core_find_regmap(pmcdev->regmap_list, devid);
-		if (map)
-			pmc_core_pmc_add(pmcdev, pwrm_base, map, pmc_idx);
-	}
+	map = pmc_core_find_regmap(pmcdev->regmap_list, devid);
+	if (!map)
+		return -ENODEV;
 
-	if (pmc_idx != PMC_IDX_SOC)
-		iounmap(ssram);
+	return pmc_core_pmc_add(pmcdev, pwrm_base, map, PMC_IDX_MAIN);
 }
 
 int pmc_core_ssram_init(struct pmc_dev *pmcdev)
 {
-	void __iomem *ssram;
 	struct pci_dev *pcidev;
-	u64 ssram_base;
 	int ret;
 
 	pcidev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(20, 2));
@@ -113,18 +121,14 @@ int pmc_core_ssram_init(struct pmc_dev *pmcdev)
 	if (ret)
 		goto release_dev;
 
-	ssram_base = pcidev->resource[0].start;
-	ssram = ioremap(ssram_base, SSRAM_HDR_SIZE);
-	if (!ssram)
-		goto disable_dev;
-
 	pmcdev->ssram_pcidev = pcidev;
 
-	pmc_core_ssram_get_pmc(pmcdev, ssram, 0, PMC_IDX_SOC);
-	pmc_core_ssram_get_pmc(pmcdev, ssram, SSRAM_IOE_OFFSET, PMC_IDX_IOE);
-	pmc_core_ssram_get_pmc(pmcdev, ssram, SSRAM_PCH_OFFSET, PMC_IDX_PCH);
+	ret = pmc_core_ssram_get_pmc(pmcdev, PMC_IDX_MAIN, 0);
+	if (ret)
+		goto disable_dev;
 
-	iounmap(ssram);
+	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;