diff options
| author | Alex Deucher <alexander.deucher@amd.com> | 2015-11-11 23:14:39 -0500 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2015-12-21 16:42:31 -0500 |
| commit | 60d8edd415e9da63599c7601707ca78ad74a927e (patch) | |
| tree | ba49fa9df13bde6909bda2a16ba1157bd2e6b995 /drivers/gpu/drm/drm_pci.c | |
| parent | 16881da6c0b9db5fca95b96b0f02720e94c92629 (diff) | |
drm: add drm_pcie_get_max_link_width helper (v2)
Add a helper to get the max link width of the port.
Similar to the helper to get the max link speed.
v2: fix typo in commit message
Reviewed-by: Jammy Zhou <Jammy.Zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers/gpu/drm/drm_pci.c')
| -rw-r--r-- | drivers/gpu/drm/drm_pci.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_pci.c b/drivers/gpu/drm/drm_pci.c index fcd2a86acd2c..a1fff1179a97 100644 --- a/drivers/gpu/drm/drm_pci.c +++ b/drivers/gpu/drm/drm_pci.c @@ -410,6 +410,26 @@ int drm_pcie_get_speed_cap_mask(struct drm_device *dev, u32 *mask) } EXPORT_SYMBOL(drm_pcie_get_speed_cap_mask); +int drm_pcie_get_max_link_width(struct drm_device *dev, u32 *mlw) +{ + struct pci_dev *root; + u32 lnkcap; + + *mlw = 0; + if (!dev->pdev) + return -EINVAL; + + root = dev->pdev->bus->self; + + pcie_capability_read_dword(root, PCI_EXP_LNKCAP, &lnkcap); + + *mlw = (lnkcap & PCI_EXP_LNKCAP_MLW) >> 4; + + DRM_INFO("probing mlw for device %x:%x = %x\n", root->vendor, root->device, lnkcap); + return 0; +} +EXPORT_SYMBOL(drm_pcie_get_max_link_width); + #else int drm_pci_init(struct drm_driver *driver, struct pci_driver *pdriver) |