perf/smmuv3: Allow sharing MMIO registers with the SMMU driver

Some Arm SMMUv3 implementations, for example Arm CoreLink MMU-600, embed the PMCG registers into the SMMU MMIO regions. It currently causes probe failure because the PMU and SMMU drivers request overlapping resources. Avoid the conflict by calling devm_ioremap() directly from the PMU driver. We loose some sanity-checking of the memory map provided by firmware, which doesn't seem catastrophic. Backport from: https://lore.kernel.org/linux-arm-kernel/[email protected]/ Signed-off-by: Jean-Philippe Brucker <[email protected]> Signed-off-by: Tuan Phan <[email protected]> Signed-off-by: Tuan Phan <[email protected]>
AmpereComputing · Jun 30, 2020 · 1164351 · 1164351
1 parent 43046fc
commit 1164351
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Showing 2 changed files with 20 additions and 7 deletions.
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
@@ -2854,7 +2854,7 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
 	}
 	ioaddr = res->start;
 
-	smmu->base = devm_ioremap_resource(dev, res);
+	smmu->base = devm_ioremap(dev, res->start, resource_size(res));
 	if (IS_ERR(smmu->base))
 		return PTR_ERR(smmu->base);
 

diff --git a/drivers/perf/arm_smmuv3_pmu.c b/drivers/perf/arm_smmuv3_pmu.c
@@ -723,19 +723,32 @@ static int smmu_pmu_probe(struct platform_device *pdev)
 		.capabilities	= PERF_PMU_CAP_NO_EXCLUDE,
 	};
 
+	/*
+	 * If the PMCG registers are embedded into the SMMU regions, the
+	 * resources have to be shared with the SMMU driver. Use ioremap()
+	 * rather than ioremap_resource() to avoid conflicts.
+	 */
 	res_0 = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	smmu_pmu->reg_base = devm_ioremap_resource(dev, res_0);
-	if (IS_ERR(smmu_pmu->reg_base))
-		return PTR_ERR(smmu_pmu->reg_base);
+	if (!res_0)
+		return -ENXIO;
+
+	smmu_pmu->reg_base = devm_ioremap(dev, res_0->start,
+					  resource_size(res_0));
+	if (!smmu_pmu->reg_base)
+		return -ENOMEM;
 
 	cfgr = readl_relaxed(smmu_pmu->reg_base + SMMU_PMCG_CFGR);
 
 	/* Determine if page 1 is present */
 	if (cfgr & SMMU_PMCG_CFGR_RELOC_CTRS) {
 		res_1 = platform_get_resource(pdev, IORESOURCE_MEM, 1);
-		smmu_pmu->reloc_base = devm_ioremap_resource(dev, res_1);
-		if (IS_ERR(smmu_pmu->reloc_base))
-			return PTR_ERR(smmu_pmu->reloc_base);
+		if (!res_1)
+			return -ENXIO;
+
+		smmu_pmu->reloc_base = devm_ioremap(dev, res_1->start,
+						    resource_size(res_1));
+		if (!smmu_pmu->reloc_base)
+			return -ENOMEM;
 	} else {
 		smmu_pmu->reloc_base = smmu_pmu->reg_base;
 	}