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Commit f4297784 authored by Dave Airlie's avatar Dave Airlie
Browse files

drm/pci: add support for getting the supported link bw. 



This should work for PCIE3.0 as well.

Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent cdcac9cd

drivers/gpu/drm/drm_pci.c

+49 −0
Original line number Diff line number Diff line
@@ -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);

include/drm/drmP.h

+5 −0
Original line number Diff line number Diff line
@@ -1761,6 +1761,11 @@ extern int drm_get_pci_dev(struct pci_dev *pdev, 
			   const struct pci_device_id *ent,

			   struct drm_driver *driver);



#define DRM_PCIE_SPEED_25 1

#define DRM_PCIE_SPEED_50 2

#define DRM_PCIE_SPEED_80 4



extern int drm_pcie_get_speed_cap_mask(struct drm_device *dev, u32 *speed_mask);



/* platform section */

extern int drm_platform_init(struct drm_driver *driver, struct platform_device *platform_device);