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authorTal Gilboa <talgi@mellanox.com>2018-03-30 07:44:05 -0500
committerBjorn Helgaas <bhelgaas@google.com>2018-03-30 15:33:38 -0500
commit6cf57be0f78e289aaf236f8bc55c40ea6c422c75 (patch)
tree6a139948424dfd0d349b2baf06bdcd4370285427 /drivers/pci
parent1acfb9b7ee0b1881bb8e875b6757976e48293ec4 (diff)
downloadlinux-6cf57be0f78e289aaf236f8bc55c40ea6c422c75.tar.bz2
PCI: Add pcie_get_speed_cap() to find max supported link speed
Add pcie_get_speed_cap() to find the max link speed supported by a device. Change max_link_speed_show() to use pcie_get_speed_cap(). Signed-off-by: Tal Gilboa <talgi@mellanox.com> [bhelgaas: return speed directly instead of error and *speed, don't export outside drivers/pci] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/pci-sysfs.c28
-rw-r--r--drivers/pci/pci.c44
-rw-r--r--drivers/pci/pci.h10
3 files changed, 56 insertions, 26 deletions
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 7dc5be545d18..c2ea05fbbf1d 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -158,33 +158,9 @@ static DEVICE_ATTR_RO(resource);
static ssize_t max_link_speed_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- struct pci_dev *pci_dev = to_pci_dev(dev);
- u32 linkcap;
- int err;
- const char *speed;
-
- err = pcie_capability_read_dword(pci_dev, PCI_EXP_LNKCAP, &linkcap);
- if (err)
- return -EINVAL;
-
- switch (linkcap & PCI_EXP_LNKCAP_SLS) {
- case PCI_EXP_LNKCAP_SLS_16_0GB:
- speed = "16 GT/s";
- break;
- case PCI_EXP_LNKCAP_SLS_8_0GB:
- speed = "8 GT/s";
- break;
- case PCI_EXP_LNKCAP_SLS_5_0GB:
- speed = "5 GT/s";
- break;
- case PCI_EXP_LNKCAP_SLS_2_5GB:
- speed = "2.5 GT/s";
- break;
- default:
- speed = "Unknown speed";
- }
+ struct pci_dev *pdev = to_pci_dev(dev);
- return sprintf(buf, "%s\n", speed);
+ return sprintf(buf, "%s\n", PCIE_SPEED2STR(pcie_get_speed_cap(pdev)));
}
static DEVICE_ATTR_RO(max_link_speed);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index f6a4dd10d9b0..b29d3436ee9f 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5147,6 +5147,50 @@ int pcie_get_minimum_link(struct pci_dev *dev, enum pci_bus_speed *speed,
EXPORT_SYMBOL(pcie_get_minimum_link);
/**
+ * pcie_get_speed_cap - query for the PCI device's link speed capability
+ * @dev: PCI device to query
+ *
+ * Query the PCI device speed capability. Return the maximum link speed
+ * supported by the device.
+ */
+enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev)
+{
+ u32 lnkcap2, lnkcap;
+
+ /*
+ * PCIe r4.0 sec 7.5.3.18 recommends using the Supported Link
+ * Speeds Vector in Link Capabilities 2 when supported, falling
+ * back to Max Link Speed in Link Capabilities otherwise.
+ */
+ pcie_capability_read_dword(dev, PCI_EXP_LNKCAP2, &lnkcap2);
+ if (lnkcap2) { /* PCIe r3.0-compliant */
+ if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_16_0GB)
+ return PCIE_SPEED_16_0GT;
+ else if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_8_0GB)
+ return PCIE_SPEED_8_0GT;
+ else if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_5_0GB)
+ return PCIE_SPEED_5_0GT;
+ else if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_2_5GB)
+ return PCIE_SPEED_2_5GT;
+ return PCI_SPEED_UNKNOWN;
+ }
+
+ pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &lnkcap);
+ if (lnkcap) {
+ if (lnkcap & PCI_EXP_LNKCAP_SLS_16_0GB)
+ return PCIE_SPEED_16_0GT;
+ else if (lnkcap & PCI_EXP_LNKCAP_SLS_8_0GB)
+ return PCIE_SPEED_8_0GT;
+ else if (lnkcap & PCI_EXP_LNKCAP_SLS_5_0GB)
+ return PCIE_SPEED_5_0GT;
+ else if (lnkcap & PCI_EXP_LNKCAP_SLS_2_5GB)
+ return PCIE_SPEED_2_5GT;
+ }
+
+ return PCI_SPEED_UNKNOWN;
+}
+
+/**
* pci_select_bars - Make BAR mask from the type of resource
* @dev: the PCI device for which BAR mask is made
* @flags: resource type mask to be selected
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index fcd81911b127..1186d8be6055 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -253,6 +253,16 @@ bool pci_bus_clip_resource(struct pci_dev *dev, int idx);
void pci_reassigndev_resource_alignment(struct pci_dev *dev);
void pci_disable_bridge_window(struct pci_dev *dev);
+/* PCIe link information */
+#define PCIE_SPEED2STR(speed) \
+ ((speed) == PCIE_SPEED_16_0GT ? "16 GT/s" : \
+ (speed) == PCIE_SPEED_8_0GT ? "8 GT/s" : \
+ (speed) == PCIE_SPEED_5_0GT ? "5 GT/s" : \
+ (speed) == PCIE_SPEED_2_5GT ? "2.5 GT/s" : \
+ "Unknown speed")
+
+enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev);
+
/* Single Root I/O Virtualization */
struct pci_sriov {
int pos; /* Capability position */