diff options
| author | Tal Gilboa <talgi@mellanox.com> | 2018-03-30 07:44:05 -0500 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2018-03-30 15:33:38 -0500 |
| commit | 6cf57be0f78e289aaf236f8bc55c40ea6c422c75 (patch) | |
| tree | 6a139948424dfd0d349b2baf06bdcd4370285427 /drivers/pci/pci.c | |
| parent | 1acfb9b7ee0b1881bb8e875b6757976e48293ec4 (diff) | |
| download | linux-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/pci.c')
| -rw-r--r-- | drivers/pci/pci.c | 44 |
1 files changed, 44 insertions, 0 deletions
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 |