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authorTal Gilboa <talgi@mellanox.com>2018-03-30 15:24:36 +0200
committerBjorn Helgaas <bhelgaas@google.com>2018-03-30 22:33:38 +0200
commitc70b65fb7f121da7d01f62588ce6abb4741f513f (patch)
tree383cdda6cad94b1ef9b3f116382221c3a379089e /drivers/pci
parentPCI: Add pcie_get_speed_cap() to find max supported link speed (diff)
downloadlinux-c70b65fb7f121da7d01f62588ce6abb4741f513f.tar.xz
linux-c70b65fb7f121da7d01f62588ce6abb4741f513f.zip
PCI: Add pcie_get_width_cap() to find max supported link width
Add pcie_get_width_cap() to find the max link width supported by a device. Change max_link_width_show() to use pcie_get_width_cap(). Signed-off-by: Tal Gilboa <talgi@mellanox.com> [bhelgaas: return width directly instead of error and *width, 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.c10
-rw-r--r--drivers/pci/pci.c18
-rw-r--r--drivers/pci/pci.h1
3 files changed, 21 insertions, 8 deletions
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index c2ea05fbbf1d..63d0952684fb 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -167,15 +167,9 @@ static DEVICE_ATTR_RO(max_link_speed);
static ssize_t max_link_width_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- struct pci_dev *pci_dev = to_pci_dev(dev);
- u32 linkcap;
- int err;
-
- err = pcie_capability_read_dword(pci_dev, PCI_EXP_LNKCAP, &linkcap);
- if (err)
- return -EINVAL;
+ struct pci_dev *pdev = to_pci_dev(dev);
- return sprintf(buf, "%u\n", (linkcap & PCI_EXP_LNKCAP_MLW) >> 4);
+ return sprintf(buf, "%u\n", pcie_get_width_cap(pdev));
}
static DEVICE_ATTR_RO(max_link_width);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index b29d3436ee9f..43075be79388 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5191,6 +5191,24 @@ enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev)
}
/**
+ * pcie_get_width_cap - query for the PCI device's link width capability
+ * @dev: PCI device to query
+ *
+ * Query the PCI device width capability. Return the maximum link width
+ * supported by the device.
+ */
+enum pcie_link_width pcie_get_width_cap(struct pci_dev *dev)
+{
+ u32 lnkcap;
+
+ pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &lnkcap);
+ if (lnkcap)
+ return (lnkcap & PCI_EXP_LNKCAP_MLW) >> 4;
+
+ return PCIE_LNK_WIDTH_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 1186d8be6055..66738f1050c0 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -262,6 +262,7 @@ void pci_disable_bridge_window(struct pci_dev *dev);
"Unknown speed")
enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev);
+enum pcie_link_width pcie_get_width_cap(struct pci_dev *dev);
/* Single Root I/O Virtualization */
struct pci_sriov {