@@ -388,6 +388,84 @@ static int mlx4_dev_cap(struct mlx4_dev *dev, struct mlx4_dev_cap *dev_cap)
return 0;
}
+
+static int mlx4_get_pcie_dev_link_caps(struct mlx4_dev *dev,
+ enum pci_bus_speed *speed,
+ enum pcie_link_width *width)
+{
+ u32 lnkcap1, lnkcap2;
+ int err1, err2;
+
+#define PCIE_MLW_CAP_SHIFT 4 /* start of MLW mask in link capabilities */
+
+ *speed = PCI_SPEED_UNKNOWN;
+ *width = PCIE_LNK_WIDTH_UNKNOWN;
+
+ err1 = pcie_capability_read_dword(dev->pdev, PCI_EXP_LNKCAP, &lnkcap1);
+ err2 = pcie_capability_read_dword(dev->pdev, PCI_EXP_LNKCAP2, &lnkcap2);
+ if (!err2 && lnkcap2) { /* PCIe r3.0-compliant */
+ if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_8_0GB)
+ *speed = PCIE_SPEED_8_0GT;
+ else if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_5_0GB)
+ *speed = PCIE_SPEED_5_0GT;
+ else if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_2_5GB)
+ *speed = PCIE_SPEED_2_5GT;
+ }
+ if (!err1) {
+ *width = (lnkcap1 & PCI_EXP_LNKCAP_MLW) >> PCIE_MLW_CAP_SHIFT;
+ if (!lnkcap2) { /* pre-r3.0 */
+ if (lnkcap1 & PCI_EXP_LNKCAP_SLS_5_0GB)
+ *speed = PCIE_SPEED_5_0GT;
+ else if (lnkcap1 & PCI_EXP_LNKCAP_SLS_2_5GB)
+ *speed = PCIE_SPEED_2_5GT;
+ }
+ }
+
+ if (*speed == PCI_SPEED_UNKNOWN || *width == PCIE_LNK_WIDTH_UNKNOWN) {
+ return err1 ? err1 :
+ err2 ? err2 : -EINVAL;
+ }
+ return 0;
+}
+
+static void mlx4_check_pcie_caps(struct mlx4_dev *dev)
+{
+ enum pcie_link_width width, width_cap;
+ enum pci_bus_speed speed, speed_cap;
+ int err;
+
+#define PCIE_SPEED_STR(speed) \
+ (speed == PCIE_SPEED_8_0GT ? "8.0GT/s" : \
+ speed == PCIE_SPEED_5_0GT ? "5.0GT/s" : \
+ speed == PCIE_SPEED_2_5GT ? "2.5GT/s" : \
+ "Unknown")
+
+ err = mlx4_get_pcie_dev_link_caps(dev, &speed_cap, &width_cap);
+ if (err) {
+ mlx4_warn(dev,
+ "Unable to determine PCIe device BW capabilities\n");
+ return;
+ }
+
+ err = pcie_get_minimum_link(dev->pdev, &speed, &width);
+ if (err || speed == PCI_SPEED_UNKNOWN ||
+ width == PCIE_LNK_WIDTH_UNKNOWN) {
+ mlx4_warn(dev,
+ "Unable to determine PCI device chain minimum BW\n");
+ return;
+ }
+
+ if (width != width_cap || speed != speed_cap)
+ mlx4_warn(dev,
+ "PCIe BW is different than device's capability\n");
+
+ mlx4_info(dev, "PCIe link speed is %s, device supports %s\n",
+ PCIE_SPEED_STR(speed), PCIE_SPEED_STR(speed_cap));
+ mlx4_info(dev, "PCIe link width is x%d, device supports x%d\n",
+ width, width_cap);
+ return;
+}
+
/*The function checks if there are live vf, return the num of them*/
static int mlx4_how_many_lives_vf(struct mlx4_dev *dev)
{
@@ -2292,6 +2370,12 @@ slave_start:
goto err_mfunc;
}
+ /* check if the device is functioning at its maximum possible speed.
+ * No return code for this call, just warn the user in case of PCI
+ * express device capabilities are under-satisfied by the bus.
+ */
+ mlx4_check_pcie_caps(dev);
+
/* In master functions, the communication channel must be initialized
* after obtaining its address from fw */
if (mlx4_is_master(dev)) {