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From:   "David E. Box" <david.e.box@linux.intel.com>
To:     linux-kernel@vger.kernel.org, platform-driver-x86@vger.kernel.org,
        ilpo.jarvinen@linux.intel.com, rajvi.jingar@linux.intel.com
Subject: [PATCH V3 09/16] platform/x86/intel/pmc: Allow pmc_core_ssram_init to fail
Date:   Wed, 11 Oct 2023 19:38:33 -0700
Message-Id: <20231012023840.3845703-10-david.e.box@linux.intel.com>
In-Reply-To: <20231012023840.3845703-1-david.e.box@linux.intel.com>
References: <20231012023840.3845703-1-david.e.box@linux.intel.com>
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Currently, if the PMC SSRAM initialization fails, no error is returned and
the only indication is that a PMC device has not been created.  Instead,
allow an error to be returned and handled directly by the caller.

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
---
V3 - New patch split from V2 PATCH 9
   - Add dev_warn on pmc_core_ssram_init fail

 drivers/platform/x86/intel/pmc/core.h       |  2 +-
 drivers/platform/x86/intel/pmc/core.h       |  2 +-
 drivers/platform/x86/intel/pmc/core_ssram.c | 21 +++++++++++++--------
 drivers/platform/x86/intel/pmc/mtl.c        | 12 ++++++++----
 3 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/drivers/platform/x86/intel/pmc/core.h b/drivers/platform/x86/intel/pmc/core.h
index ccf24e0f5e50..edaa70067e41 100644
--- a/drivers/platform/x86/intel/pmc/core.h
+++ b/drivers/platform/x86/intel/pmc/core.h
@@ -492,7 +492,7 @@ int pmc_core_resume_common(struct pmc_dev *pmcdev);
 int get_primary_reg_base(struct pmc *pmc);
 extern void pmc_core_get_low_power_modes(struct pmc_dev *pmcdev);
 
-extern void pmc_core_ssram_init(struct pmc_dev *pmcdev);
+extern int pmc_core_ssram_init(struct pmc_dev *pmcdev);
 
 int spt_core_init(struct pmc_dev *pmcdev);
 int cnp_core_init(struct pmc_dev *pmcdev);
diff --git a/drivers/platform/x86/intel/pmc/core_ssram.c b/drivers/platform/x86/intel/pmc/core_ssram.c
index 13fa16f0d52e..815950713e25 100644
--- a/drivers/platform/x86/intel/pmc/core_ssram.c
+++ b/drivers/platform/x86/intel/pmc/core_ssram.c
@@ -35,20 +35,20 @@ static inline u64 get_base(void __iomem *addr, u32 offset)
 	return lo_hi_readq(addr + offset) & GENMASK_ULL(63, 3);
 }
 
-static void
+static int
 pmc_core_pmc_add(struct pmc_dev *pmcdev, u64 pwrm_base,
 		 const struct pmc_reg_map *reg_map, int pmc_index)
 {
 	struct pmc *pmc = pmcdev->pmcs[pmc_index];
 
 	if (!pwrm_base)
-		return;
+		return -ENODEV;
 
 	/* Memory for primary PMC has been allocated in core.c */
 	if (!pmc) {
 		pmc = devm_kzalloc(&pmcdev->pdev->dev, sizeof(*pmc), GFP_KERNEL);
 		if (!pmc)
-			return;
+			return -ENOMEM;
 	}
 
 	pmc->map = reg_map;
@@ -57,10 +57,12 @@ pmc_core_pmc_add(struct pmc_dev *pmcdev, u64 pwrm_base,
 
 	if (!pmc->regbase) {
 		devm_kfree(&pmcdev->pdev->dev, pmc);
-		return;
+		return -ENOMEM;
 	}
 
 	pmcdev->pmcs[pmc_index] = pmc;
+
+	return 0;
 }
 
 static void
@@ -96,7 +98,7 @@ pmc_core_ssram_get_pmc(struct pmc_dev *pmcdev, void __iomem *ssram, u32 offset,
 		iounmap(ssram);
 }
 
-void pmc_core_ssram_init(struct pmc_dev *pmcdev)
+int pmc_core_ssram_init(struct pmc_dev *pmcdev)
 {
 	void __iomem *ssram;
 	struct pci_dev *pcidev;
@@ -105,7 +107,7 @@ void pmc_core_ssram_init(struct pmc_dev *pmcdev)
 
 	pcidev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(20, 2));
 	if (!pcidev)
-		goto out;
+		return -ENODEV;
 
 	ret = pcim_enable_device(pcidev);
 	if (ret)
@@ -123,11 +125,14 @@ void pmc_core_ssram_init(struct pmc_dev *pmcdev)
 	pmc_core_ssram_get_pmc(pmcdev, ssram, SSRAM_PCH_OFFSET, PMC_IDX_PCH);
 
 	iounmap(ssram);
-out:
-	return;
+
+	return 0;
 
 disable_dev:
+	pmcdev->ssram_pcidev = NULL;
 	pci_disable_device(pcidev);
 release_dev:
 	pci_dev_put(pcidev);
+
+	return ret;
 }
diff --git a/drivers/platform/x86/intel/pmc/mtl.c b/drivers/platform/x86/intel/pmc/mtl.c
index c3b5f4fe01d1..d1d3d33fb4b8 100644
--- a/drivers/platform/x86/intel/pmc/mtl.c
+++ b/drivers/platform/x86/intel/pmc/mtl.c
@@ -990,12 +990,16 @@ int mtl_core_init(struct pmc_dev *pmcdev)
 	mtl_d3_fixup();
 
 	pmcdev->resume = mtl_resume;
-
 	pmcdev->regmap_list = mtl_pmc_info_list;
-	pmc_core_ssram_init(pmcdev);
 
-	/* If regbase not assigned, set map and discover using legacy method */
-	if (!pmc->regbase) {
+	/*
+	 * If ssram init fails use legacy method to at least get the
+	 * primary PMC
+	 */
+	ret = pmc_core_ssram_init(pmcdev);
+	if (ret) {
+		dev_warn(&pmcdev->pdev->dev,
+			 "ssram init failed, %d, using legacy init\n", ret);
 		pmc->map = &mtl_socm_reg_map;
 		ret = get_primary_reg_base(pmc);
 		if (ret)
-- 
2.34.1