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path: root/drivers/gpu/drm/drm_pci.c
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Diffstat (limited to 'drivers/gpu/drm/drm_pci.c')
-rw-r--r--drivers/gpu/drm/drm_pci.c49
1 files changed, 49 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_pci.c b/drivers/gpu/drm/drm_pci.c
index 13f3d936472..5320364582c 100644
--- a/drivers/gpu/drm/drm_pci.c
+++ b/drivers/gpu/drm/drm_pci.c
@@ -465,3 +465,52 @@ void drm_pci_exit(struct drm_driver *driver, struct pci_driver *pdriver)
DRM_INFO("Module unloaded\n");
}
EXPORT_SYMBOL(drm_pci_exit);
+
+int drm_pcie_get_speed_cap_mask(struct drm_device *dev, u32 *mask)
+{
+ struct pci_dev *root;
+ int pos;
+ u32 lnkcap, lnkcap2;
+
+ *mask = 0;
+ if (!dev->pdev)
+ return -EINVAL;
+
+ if (!pci_is_pcie(dev->pdev))
+ return -EINVAL;
+
+ root = dev->pdev->bus->self;
+
+ pos = pci_pcie_cap(root);
+ if (!pos)
+ return -EINVAL;
+
+ /* we've been informed via and serverworks don't make the cut */
+ if (root->vendor == PCI_VENDOR_ID_VIA ||
+ root->vendor == PCI_VENDOR_ID_SERVERWORKS)
+ return -EINVAL;
+
+ pci_read_config_dword(root, pos + PCI_EXP_LNKCAP, &lnkcap);
+ pci_read_config_dword(root, pos + PCI_EXP_LNKCAP2, &lnkcap2);
+
+ lnkcap &= PCI_EXP_LNKCAP_SLS;
+ lnkcap2 &= 0xfe;
+
+ if (lnkcap2) { /* PCIE GEN 3.0 */
+ if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_2_5GB)
+ *mask |= DRM_PCIE_SPEED_25;
+ if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_5_0GB)
+ *mask |= DRM_PCIE_SPEED_50;
+ if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_8_0GB)
+ *mask |= DRM_PCIE_SPEED_80;
+ } else {
+ if (lnkcap & 1)
+ *mask |= DRM_PCIE_SPEED_25;
+ if (lnkcap & 2)
+ *mask |= DRM_PCIE_SPEED_50;
+ }
+
+ DRM_INFO("probing gen 2 caps for device %x:%x = %x/%x\n", root->vendor, root->device, lnkcap, lnkcap2);
+ return 0;
+}
+EXPORT_SYMBOL(drm_pcie_get_speed_cap_mask);