[PATCH v8 1/3] PCI: mediatek: Use actual physical address instead of virt_to_phys()

[Caleb James DeLisle]

From: Manivannan Sadhasivam <manivannan.sadhasivam at oss.qualcomm.com>

The driver previously used virt_to_phys() on the ioremapped register base
(port->base) to compute the MSI message address. Using virt_to_phys() on an
IO mapped address is incorrect because it expects a kernel virtual address.

To fix it, store the physical start of the I/O register region in
mtk_pcie_port->phys_base and use it to build the MSI address. This replaces
the incorrect virt_to_phys() usage and ensures MSI addresses are generated
correctly.

Fixes: 43e6409db64d ("PCI: mediatek: Add MSI support for MT2712 and MT7622")
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam at oss.qualcomm.com>
Tested-by: Caleb James DeLisle <cjd at cjdns.fr>
---
 drivers/pci/controller/pcie-mediatek.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
index 75722524fe74..c503fbd774d0 100644
--- a/drivers/pci/controller/pcie-mediatek.c
+++ b/drivers/pci/controller/pcie-mediatek.c
@@ -175,6 +175,7 @@ struct mtk_pcie_soc {
 /**
  * struct mtk_pcie_port - PCIe port information
  * @base: IO mapped register base
+ * @phys_base: Physical address of the I/O register base region
  * @list: port list
  * @pcie: pointer to PCIe host info
  * @reset: pointer to port reset control
@@ -196,6 +197,7 @@ struct mtk_pcie_soc {
  */
 struct mtk_pcie_port {
 	void __iomem *base;
+	phys_addr_t phys_base;
 	struct list_head list;
 	struct mtk_pcie *pcie;
 	struct reset_control *reset;
@@ -405,7 +407,7 @@ static void mtk_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 	phys_addr_t addr;
 
 	/* MT2712/MT7622 only support 32-bit MSI addresses */
-	addr = virt_to_phys(port->base + PCIE_MSI_VECTOR);
+	addr = port->phys_base + PCIE_MSI_VECTOR;
 	msg->address_hi = 0;
 	msg->address_lo = lower_32_bits(addr);
 
@@ -520,7 +522,7 @@ static void mtk_pcie_enable_msi(struct mtk_pcie_port *port)
 	u32 val;
 	phys_addr_t msg_addr;
 
-	msg_addr = virt_to_phys(port->base + PCIE_MSI_VECTOR);
+	msg_addr = port->phys_base + PCIE_MSI_VECTOR;
 	val = lower_32_bits(msg_addr);
 	writel(val, port->base + PCIE_IMSI_ADDR);
 
@@ -953,6 +955,7 @@ static int mtk_pcie_parse_port(struct mtk_pcie *pcie,
 	struct mtk_pcie_port *port;
 	struct device *dev = pcie->dev;
 	struct platform_device *pdev = to_platform_device(dev);
+	struct resource *res;
 	char name[20];
 	int err;
 
@@ -961,7 +964,14 @@ static int mtk_pcie_parse_port(struct mtk_pcie *pcie,
 		return -ENOMEM;
 
 	snprintf(name, sizeof(name), "port%d", slot);
-	port->base = devm_platform_ioremap_resource_byname(pdev, name);
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
+	if (!res) {
+		dev_err(dev, "failed to get port%d base\n", slot);
+		return -EINVAL;
+	}
+
+	port->phys_base = res->start;
+	port->base = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(port->base)) {
 		dev_err(dev, "failed to map port%d base\n", slot);
 		return PTR_ERR(port->base);
-- 
2.39.5