From 60d8edd415e9da63599c7601707ca78ad74a927e Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexander.deucher@amd.com>
Date: Wed, 11 Nov 2015 23:14:39 -0500
Subject: [PATCH] drm: add drm_pcie_get_max_link_width helper (v2)
Git-commit: 60d8edd415e9da63599c7601707ca78ad74a927e
Patch-mainline: 4.5-rc1
References: bsc#991038

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>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/drm_pci.c |   20 ++++++++++++++++++++
 include/drm/drmP.h        |    1 +
 2 files changed, 21 insertions(+)

--- 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 d
 }
 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)
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1117,6 +1117,7 @@ static inline int drm_pci_set_busid(stru
 #define DRM_PCIE_SPEED_80 4
 
 extern int drm_pcie_get_speed_cap_mask(struct drm_device *dev, u32 *speed_mask);
+extern int drm_pcie_get_max_link_width(struct drm_device *dev, u32 *mlw);
 
 /* platform section */
 extern int drm_platform_init(struct drm_driver *driver, struct platform_device *platform_device);
