FROMLIST: PCI: qcom: Honor IOMMU provider's #iommu-cells in qcom_pcie_config_sid_1_9_0()

drivers/pci/controller/dwc/pcie-qcom.c

@@ -1143,50 +1143,90 @@ static void qcom_pcie_deinit_2_7_0(struct qcom_pcie *pcie)
 
 static int qcom_pcie_config_sid_1_9_0(struct qcom_pcie *pcie)
 {
-	/* iommu map structure */
-	struct {
-		u32 bdf;
-		u32 phandle;
-		u32 smmu_sid;
-		u32 smmu_sid_len;
-	} *map;
 	void __iomem *bdf_to_sid_base = pcie->parf + PARF_BDF_TO_SID_TABLE_N;
 	struct device *dev = pcie->pci->dev;
+	struct device_node *iommu_np;
 	u8 qcom_pcie_crc8_table[CRC8_TABLE_SIZE];
-	int i, nr_map, size = 0;
-	u32 smmu_sid_base;
+	const __be32 *map;
+	u32 iommu_cells, entry_cells, phandle, smmu_sid_base;
+	int i, nr_cells, nr_map, size = 0;
 	u32 val;
 
-	of_get_property(dev->of_node, "iommu-map", &size);
-	if (!size)
+	map = of_get_property(dev->of_node, "iommu-map", &size);
+	if (!map || !size)
 		return 0;
 
+	if (size % sizeof(*map)) {
+		dev_err(dev, "Malformed iommu-map property\n");
+		return -EINVAL;
+	}
+	nr_cells = size / sizeof(*map);
+
+	/*
+	 * Each iommu-map entry is: rid-base (1 cell), phandle (1 cell),
+	 * IOMMU specifier (#iommu-cells cells), length (1 cell). Read
+	 * #iommu-cells from the IOMMU provider referenced by the first
+	 * entry to compute the per-entry stride.
+	 */
+	phandle = be32_to_cpu(map[1]);
+	iommu_np = of_find_node_by_phandle(phandle);
+	if (!iommu_np) {
+		dev_err(dev, "Failed to find IOMMU node in iommu-map\n");
+		return -ENODEV;
+	}
+
+	if (of_property_read_u32(iommu_np, "#iommu-cells", &iommu_cells))
+		iommu_cells = 1;
+	of_node_put(iommu_np);
+
+	entry_cells = 3 + iommu_cells;
+
+	/*
+	 * Retain backward compatibility with DTs that describe iommu-map
+	 * with 4-cell entries against an IOMMU declaring #iommu-cells = 2,
+	 * matching the fallback in drivers/of/base.c::of_check_bad_map().
+	 */
+	if (iommu_cells == 2 && !(nr_cells % 4)) {
+		bool legacy = true;
+
+		for (i = 0; i < nr_cells; i += 4) {
+			if (be32_to_cpu(map[i + 1]) != phandle ||
+			    be32_to_cpu(map[i + 3]) != 1) {
+				legacy = false;
+				break;
+			}
+		}
+
+		if (legacy) {
+			dev_warn_once(dev, "iommu-map has 1-cell entries targeting 2-cell #iommu-cells, treating as 1-cell output\n");
+			entry_cells = 4;
+		}
+	}
+
+	if (nr_cells % entry_cells) {
+		dev_err(dev, "Malformed iommu-map property\n");
+		return -EINVAL;
+	}
+	nr_map = nr_cells / entry_cells;
+
 	/* Enable BDF to SID translation by disabling bypass mode (default) */
 	val = readl(pcie->parf + PARF_BDF_TO_SID_CFG);
 	val &= ~BDF_TO_SID_BYPASS;
 	writel(val, pcie->parf + PARF_BDF_TO_SID_CFG);
 
-	map = kzalloc(size, GFP_KERNEL);
-	if (!map)
-		return -ENOMEM;
-
-	of_property_read_u32_array(dev->of_node, "iommu-map", (u32 *)map,
-				   size / sizeof(u32));
-
-	nr_map = size / (sizeof(*map));
-
 	crc8_populate_msb(qcom_pcie_crc8_table, QCOM_PCIE_CRC8_POLYNOMIAL);
 
 	/* Registers need to be zero out first */
 	memset_io(bdf_to_sid_base, 0, CRC8_TABLE_SIZE * sizeof(u32));
 
 	/* Extract the SMMU SID base from the first entry of iommu-map */
-	smmu_sid_base = map[0].smmu_sid;
+	smmu_sid_base = be32_to_cpu(map[2]);
 
 	/* Look for an available entry to hold the mapping */
 	for (i = 0; i < nr_map; i++) {
-		__be16 bdf_be = cpu_to_be16(map[i].bdf);
-		u32 val;
+		u32 bdf = be32_to_cpu(map[i * entry_cells]);
+		u32 sid = be32_to_cpu(map[i * entry_cells + 2]);
+		__be16 bdf_be = cpu_to_be16(bdf);
 		u8 hash;
 
 		hash = crc8(qcom_pcie_crc8_table, (u8 *)&bdf_be, sizeof(bdf_be), 0);
@@ -1208,12 +1248,10 @@ static int qcom_pcie_config_sid_1_9_0(struct qcom_pcie *pcie)
 		}
 
 		/* BDF [31:16] | SID [15:8] | NEXT [7:0] */
-		val = map[i].bdf << 16 | (map[i].smmu_sid - smmu_sid_base) << 8 | 0;
+		val = bdf << 16 | (sid - smmu_sid_base) << 8 | 0;
 		writel(val, bdf_to_sid_base + hash * sizeof(u32));
 	}
 
-	kfree(map);
-
 	return 0;
 }