Merge branch 'pci/controller/max-link-speed'

- Add pcie_get_link_speed() to encapsulate and bounds-check
  pcie_link_speed[] accesses (Hans Zhang)

- Validate max-link-speed from DT in j721e, brcmstb, mediatek-gen3, rzg3s
  (where the actual controller constraints are known), and remove it from
  the generic OF DT accessor (Hans Zhang)

* pci/controller/max-link-speed:
  PCI: of: Remove max-link-speed generation validation
  PCI: controller: Validate max-link-speed
  PCI: j721e: Validate max-link-speed from DT
  PCI: dwc: Use pcie_get_link_speed() helper for safe array access
  PCI: Add pcie_get_link_speed() helper for safe array access

13 files changed, 41 insertions, 26 deletions

diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c
index 6f2501479c70..bfdfe98d5aba 100644
--- a/drivers/pci/controller/cadence/pci-j721e.c
+++ b/drivers/pci/controller/cadence/pci-j721e.c
@@ -202,7 +202,8 @@ static int j721e_pcie_set_link_speed(struct j721e_pcie *pcie,
 	int ret;
 
 	link_speed = of_pci_get_max_link_speed(np);
-	if (link_speed < 2)
+	if ((link_speed < 2) ||
+	    (pcie_get_link_speed(link_speed) == PCI_SPEED_UNKNOWN))
 		link_speed = 2;
 
 	val = link_speed - 1;
diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 6ae6189e9b8a..0e05c5280344 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -1081,7 +1081,7 @@ static void dw_pcie_program_presets(struct dw_pcie_rp *pp, enum pci_bus_speed sp
 static void dw_pcie_config_presets(struct dw_pcie_rp *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
-	enum pci_bus_speed speed = pcie_link_speed[pci->max_link_speed];
+	enum pci_bus_speed speed = pcie_get_link_speed(pci->max_link_speed);
 
 	/*
 	 * Lane equalization settings need to be applied for all data rates the
diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
index 5741c09dde7f..06792ba92aa7 100644
--- a/drivers/pci/controller/dwc/pcie-designware.c
+++ b/drivers/pci/controller/dwc/pcie-designware.c
@@ -861,7 +861,7 @@ static void dw_pcie_link_set_max_speed(struct dw_pcie *pci)
 	ctrl2 = dw_pcie_readl_dbi(pci, offset + PCI_EXP_LNKCTL2);
 	ctrl2 &= ~PCI_EXP_LNKCTL2_TLS;
 
-	switch (pcie_link_speed[pci->max_link_speed]) {
+	switch (pcie_get_link_speed(pci->max_link_speed)) {
 	case PCIE_SPEED_2_5GT:
 		link_speed = PCI_EXP_LNKCTL2_TLS_2_5GT;
 		break;
diff --git a/drivers/pci/controller/dwc/pcie-qcom-common.c b/drivers/pci/controller/dwc/pcie-qcom-common.c
index 01c5387e53bf..5aa73c628737 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-common.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-common.c
@@ -22,7 +22,7 @@ void qcom_pcie_common_set_equalization(struct dw_pcie *pci)
 	 * applied.
 	 */
 
-	for (speed = PCIE_SPEED_8_0GT; speed <= pcie_link_speed[pci->max_link_speed]; speed++) {
+	for (speed = PCIE_SPEED_8_0GT; speed <= pcie_get_link_speed(pci->max_link_speed); speed++) {
 		if (speed > PCIE_SPEED_32_0GT) {
 			dev_warn(dev, "Skipped equalization settings for unsupported data rate\n");
 			break;
diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c
index 8e8c58a42bc3..257c2bcb5f76 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-ep.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
@@ -152,7 +152,7 @@
 #define WAKE_DELAY_US				2000 /* 2 ms */
 
 #define QCOM_PCIE_LINK_SPEED_TO_BW(speed) \
-		Mbps_to_icc(PCIE_SPEED2MBS_ENC(pcie_link_speed[speed]))
+		Mbps_to_icc(PCIE_SPEED2MBS_ENC(pcie_get_link_speed(speed)))
 
 #define to_pcie_ep(x)				dev_get_drvdata((x)->dev)
 
@@ -531,7 +531,7 @@ skip_resources_enable:
 
 	qcom_pcie_common_set_equalization(pci);
 
-	if (pcie_link_speed[pci->max_link_speed] == PCIE_SPEED_16_0GT)
+	if (pcie_get_link_speed(pci->max_link_speed) == PCIE_SPEED_16_0GT)
 		qcom_pcie_common_set_16gt_lane_margining(pci);
 
 	/*
diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 67a16af69ddc..5c7c105bb745 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -170,7 +170,7 @@
 #define QCOM_PCIE_CRC8_POLYNOMIAL		(BIT(2) | BIT(1) | BIT(0))
 
 #define QCOM_PCIE_LINK_SPEED_TO_BW(speed) \
-		Mbps_to_icc(PCIE_SPEED2MBS_ENC(pcie_link_speed[speed]))
+		Mbps_to_icc(PCIE_SPEED2MBS_ENC(pcie_get_link_speed(speed)))
 
 struct qcom_pcie_resources_1_0_0 {
 	struct clk_bulk_data *clks;
@@ -320,7 +320,7 @@ static int qcom_pcie_start_link(struct dw_pcie *pci)
 
 	qcom_pcie_common_set_equalization(pci);
 
-	if (pcie_link_speed[pci->max_link_speed] == PCIE_SPEED_16_0GT)
+	if (pcie_get_link_speed(pci->max_link_speed) == PCIE_SPEED_16_0GT)
 		qcom_pcie_common_set_16gt_lane_margining(pci);
 
 	/* Enable Link Training state machine */
@@ -1579,7 +1579,7 @@ static void qcom_pcie_icc_opp_update(struct qcom_pcie *pcie)
 				ret);
 		}
 	} else if (pcie->use_pm_opp) {
-		freq_mbps = pcie_dev_speed_mbps(pcie_link_speed[speed]);
+		freq_mbps = pcie_dev_speed_mbps(pcie_get_link_speed(speed));
 		if (freq_mbps < 0)
 			return;
 
diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index ea7a6256450c..ab1a259fc763 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -310,7 +310,7 @@ static void tegra_pcie_icc_set(struct tegra_pcie_dw *pcie)
 	speed = FIELD_GET(PCI_EXP_LNKSTA_CLS, val);
 	width = FIELD_GET(PCI_EXP_LNKSTA_NLW, val);
 
-	val = width * PCIE_SPEED2MBS_ENC(pcie_link_speed[speed]);
+	val = width * PCIE_SPEED2MBS_ENC(pcie_get_link_speed(speed));
 
 	if (icc_set_bw(pcie->icc_path, Mbps_to_icc(val), 0))
 		dev_err(pcie->dev, "can't set bw[%u]\n", val);
diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 062f55690012..714bcab97b60 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -1442,7 +1442,7 @@ static int brcm_pcie_start_link(struct brcm_pcie *pcie)
 	cls = FIELD_GET(PCI_EXP_LNKSTA_CLS, lnksta);
 	nlw = FIELD_GET(PCI_EXP_LNKSTA_NLW, lnksta);
 	dev_info(dev, "link up, %s x%u %s\n",
-		 pci_speed_string(pcie_link_speed[cls]), nlw,
+		 pci_speed_string(pcie_get_link_speed(cls)), nlw,
 		 ssc_good ? "(SSC)" : "(!SSC)");
 
 	return 0;
@@ -2072,7 +2072,8 @@ static int brcm_pcie_probe(struct platform_device *pdev)
 		return PTR_ERR(pcie->clk);
 
 	ret = of_pci_get_max_link_speed(np);
-	pcie->gen = (ret < 0) ? 0 : ret;
+	if (pcie_get_link_speed(ret) == PCI_SPEED_UNKNOWN)
+		pcie->gen = 0;
 
 	pcie->ssc = of_property_read_bool(np, "brcm,enable-ssc");
 
diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
index 75ddb8bee168..3b903ef7d3cf 100644
--- a/drivers/pci/controller/pcie-mediatek-gen3.c
+++ b/drivers/pci/controller/pcie-mediatek-gen3.c
@@ -1150,7 +1150,7 @@ static int mtk_pcie_setup(struct mtk_gen3_pcie *pcie)
 		return err;
 
 	err = of_pci_get_max_link_speed(pcie->dev->of_node);
-	if (err) {
+	if (pcie_get_link_speed(err) != PCI_SPEED_UNKNOWN) {
 		/* Get the maximum speed supported by the controller */
 		max_speed = mtk_pcie_get_controller_max_link_speed(pcie);
 
diff --git a/drivers/pci/controller/pcie-rzg3s-host.c b/drivers/pci/controller/pcie-rzg3s-host.c
index 2809112e6317..00a11f986117 100644
--- a/drivers/pci/controller/pcie-rzg3s-host.c
+++ b/drivers/pci/controller/pcie-rzg3s-host.c
@@ -966,7 +966,7 @@ static int rzg3s_pcie_set_max_link_speed(struct rzg3s_pcie_host *host)
 	ls = readw_relaxed(host->pcie + pcie_cap + PCI_EXP_LNKSTA);
 	cs2 = readl_relaxed(host->axi + RZG3S_PCI_PCSTAT2);
 
-	switch (pcie_link_speed[host->max_link_speed]) {
+	switch (pcie_get_link_speed(host->max_link_speed)) {
 	case PCIE_SPEED_5_0GT:
 		max_supported_link_speeds = GENMASK(PCI_EXP_LNKSTA_CLS_5_0GB - 1, 0);
 		link_speed = PCI_EXP_LNKCTL2_TLS_5_0GT;
diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index 9f8eb5df279e..c216701c75dd 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -875,24 +875,19 @@ EXPORT_SYMBOL_GPL(of_pci_supply_present);
  * of_pci_get_max_link_speed - Find the maximum link speed of the given device node.
  * @node: Device tree node with the maximum link speed information.
  *
- * This function will try to find the limitation of link speed by finding
- * a property called "max-link-speed" of the given device node.
+ * This function will try to read the "max-link-speed" property of the given
+ * device tree node. It does NOT validate the value of the property.
  *
- * Return:
- * * > 0	- On success, a maximum link speed.
- * * -EINVAL	- Invalid "max-link-speed" property value, or failure to access
- *		  the property of the device tree node.
- *
- * Returns the associated max link speed from DT, or a negative value if the
- * required property is not found or is invalid.
+ * Return: Maximum link speed value on success, errno on failure.
  */
 int of_pci_get_max_link_speed(struct device_node *node)
 {
 	u32 max_link_speed;
+	int ret;
 
-	if (of_property_read_u32(node, "max-link-speed", &max_link_speed) ||
-	    max_link_speed == 0 || max_link_speed > 4)
-		return -EINVAL;
+	ret = of_property_read_u32(node, "max-link-speed", &max_link_speed);
+	if (ret)
+		return ret;
 
 	return max_link_speed;
 }
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 9540f1f1709a..4a14f88e543a 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -108,6 +108,8 @@ struct pcie_tlp_log;
 				 PCI_EXP_DEVCTL_FERE | PCI_EXP_DEVCTL_URRE)
 
 extern const unsigned char pcie_link_speed[];
+unsigned char pcie_get_link_speed(unsigned int speed);
+
 extern bool pci_early_dump;
 
 extern struct mutex pci_rescan_remove_lock;
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 675713548431..0cb6d9c35f1d 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -772,6 +772,22 @@ const unsigned char pcie_link_speed[] = {
 };
 EXPORT_SYMBOL_GPL(pcie_link_speed);
 
+/**
+ * pcie_get_link_speed - Get speed value from PCIe generation number
+ * @speed: PCIe speed (1-based: 1 = 2.5GT, 2 = 5GT, ...)
+ *
+ * Returns the speed value (e.g., PCIE_SPEED_2_5GT) if @speed is valid,
+ * otherwise returns PCI_SPEED_UNKNOWN.
+ */
+unsigned char pcie_get_link_speed(unsigned int speed)
+{
+	if (speed >= ARRAY_SIZE(pcie_link_speed))
+		return PCI_SPEED_UNKNOWN;
+
+	return pcie_link_speed[speed];
+}
+EXPORT_SYMBOL_GPL(pcie_get_link_speed);
+
 const char *pci_speed_string(enum pci_bus_speed speed)
 {
 	/* Indexed by the pci_bus_speed enum */