Merge branch 'pci/controller/mediatek'

- Add support for DT 'max-link-speed' and 'num-lanes' properties to
  restrict the link speed and width (AngeloGioacchino Del Regno)

* pci/controller/mediatek:
  PCI: mediatek-gen3: Remove unneeded semicolon
  PCI: mediatek-gen3: Add support for restricting link width
  PCI: mediatek-gen3: Add support for setting max-link-speed limit

Author: bjorn-helgaas

drivers/pci/controller/pcie-mediatek-gen3.c

@@ -28,7 +28,12 @@
 
 #include "../pci.h"
 
+#define PCIE_BASE_CFG_REG		0x14
+#define PCIE_BASE_CFG_SPEED		GENMASK(15, 8)
+
 #define PCIE_SETTING_REG		0x80
+#define PCIE_SETTING_LINK_WIDTH		GENMASK(11, 8)
+#define PCIE_SETTING_GEN_SUPPORT	GENMASK(14, 12)
 #define PCIE_PCI_IDS_1			0x9c
 #define PCI_CLASS(class)		(class << 8)
 #define PCIE_RC_MODE			BIT(0)
@@ -125,6 +130,9 @@
 
 struct mtk_gen3_pcie;
 
+#define PCIE_CONF_LINK2_CTL_STS		(PCIE_CFG_OFFSET_ADDR + 0xb0)
+#define PCIE_CONF_LINK2_LCR2_LINK_SPEED	GENMASK(3, 0)
+
 /**
  * struct mtk_gen3_pcie_pdata - differentiate between host generations
  * @power_up: pcie power_up callback
@@ -160,6 +168,8 @@ struct mtk_msi_set {
  * @phy: PHY controller block
  * @clks: PCIe clocks
  * @num_clks: PCIe clocks count for this port
+ * @max_link_speed: Maximum link speed (PCIe Gen) for this port
+ * @num_lanes: Number of PCIe lanes for this port
  * @irq: PCIe controller interrupt number
  * @saved_irq_state: IRQ enable state saved at suspend time
  * @irq_lock: lock protecting IRQ register access
@@ -180,6 +190,8 @@ struct mtk_gen3_pcie {
 	struct phy *phy;
 	struct clk_bulk_data *clks;
 	int num_clks;
+	u8 max_link_speed;
+	u8 num_lanes;
 
 	int irq;
 	u32 saved_irq_state;
@@ -381,11 +393,35 @@ static int mtk_pcie_startup_port(struct mtk_gen3_pcie *pcie)
 	int err;
 	u32 val;
 
-	/* Set as RC mode */
+	/* Set as RC mode and set controller PCIe Gen speed restriction, if any */
 	val = readl_relaxed(pcie->base + PCIE_SETTING_REG);
 	val |= PCIE_RC_MODE;
+	if (pcie->max_link_speed) {
+		val &= ~PCIE_SETTING_GEN_SUPPORT;
+
+		/* Can enable link speed support only from Gen2 onwards */
+		if (pcie->max_link_speed >= 2)
+			val |= FIELD_PREP(PCIE_SETTING_GEN_SUPPORT,
+					  GENMASK(pcie->max_link_speed - 2, 0));
+	}
+	if (pcie->num_lanes) {
+		val &= ~PCIE_SETTING_LINK_WIDTH;
+
+		/* Zero means one lane, each bit activates x2/x4/x8/x16 */
+		if (pcie->num_lanes > 1)
+			val |= FIELD_PREP(PCIE_SETTING_LINK_WIDTH,
+					  GENMASK(fls(pcie->num_lanes >> 2), 0));
+	}
 	writel_relaxed(val, pcie->base + PCIE_SETTING_REG);
 
+	/* Set Link Control 2 (LNKCTL2) speed restriction, if any */
+	if (pcie->max_link_speed) {
+		val = readl_relaxed(pcie->base + PCIE_CONF_LINK2_CTL_STS);
+		val &= ~PCIE_CONF_LINK2_LCR2_LINK_SPEED;
+		val |= FIELD_PREP(PCIE_CONF_LINK2_LCR2_LINK_SPEED, pcie->max_link_speed);
+		writel_relaxed(val, pcie->base + PCIE_CONF_LINK2_CTL_STS);
+	}
+
 	/* Set class code */
 	val = readl_relaxed(pcie->base + PCIE_PCI_IDS_1);
 	val &= ~GENMASK(31, 8);
@@ -813,6 +849,7 @@ static int mtk_pcie_parse_port(struct mtk_gen3_pcie *pcie)
 	struct device *dev = pcie->dev;
 	struct platform_device *pdev = to_platform_device(dev);
 	struct resource *regs;
+	u32 num_lanes;
 
 	regs = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcie-mac");
 	if (!regs)
@@ -858,6 +895,14 @@ static int mtk_pcie_parse_port(struct mtk_gen3_pcie *pcie)
 		return pcie->num_clks;
 	}
 
+       ret = of_property_read_u32(dev->of_node, "num-lanes", &num_lanes);
+       if (ret == 0) {
+	       if (num_lanes == 0 || num_lanes > 16 || (num_lanes != 1 && num_lanes % 2))
+			dev_warn(dev, "invalid num-lanes, using controller defaults\n");
+	       else
+			pcie->num_lanes = num_lanes;
+       }
+
 	return 0;
 }
 
@@ -1004,9 +1049,21 @@ static void mtk_pcie_power_down(struct mtk_gen3_pcie *pcie)
 	reset_control_bulk_assert(pcie->soc->phy_resets.num_resets, pcie->phy_resets);
 }
 
+static int mtk_pcie_get_controller_max_link_speed(struct mtk_gen3_pcie *pcie)
+{
+	u32 val;
+	int ret;
+
+	val = readl_relaxed(pcie->base + PCIE_BASE_CFG_REG);
+	val = FIELD_GET(PCIE_BASE_CFG_SPEED, val);
+	ret = fls(val);
+
+	return ret > 0 ? ret : -EINVAL;
+}
+
 static int mtk_pcie_setup(struct mtk_gen3_pcie *pcie)
 {
-	int err;
+	int err, max_speed;
 
 	err = mtk_pcie_parse_port(pcie);
 	if (err)
@@ -1031,6 +1088,20 @@ static int mtk_pcie_setup(struct mtk_gen3_pcie *pcie)
 	if (err)
 		return err;
 
+	err = of_pci_get_max_link_speed(pcie->dev->of_node);
+	if (err) {
+		/* Get the maximum speed supported by the controller */
+		max_speed = mtk_pcie_get_controller_max_link_speed(pcie);
+
+		/* Set max_link_speed only if the controller supports it */
+		if (max_speed >= 0 && max_speed <= err) {
+			pcie->max_link_speed = err;
+			dev_info(pcie->dev,
+				 "maximum controller link speed Gen%d, overriding to Gen%u",
+				 max_speed, pcie->max_link_speed);
+		}
+	}
+
 	/* Try link up */
 	err = mtk_pcie_startup_port(pcie);
 	if (err)