drivers/video/screen_info_pci.c

Source file repositories/reference/linux-study-clean/drivers/video/screen_info_pci.c

File Facts

System
Linux kernel
Corpus path
drivers/video/screen_info_pci.c
Extension
.c
Size
4088 bytes
Lines
159
Domain
Driver Families
Bucket
drivers/video
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (pr->start != screen_info_lfb_res_start) {
			if (__screen_info_relocation_is_valid(si, pr)) {
				/*
				 * Only update base if we have an actual
				 * relocation to a valid I/O range.
				 */
				__screen_info_set_lfb_base(si, pr->start + screen_info_lfb_offset);
				pr_info("Relocating firmware framebuffer to offset %pa[d] within %pr\n",
					&screen_info_lfb_offset, pr);
			} else {
				pr_warn("Invalid relocating, disabling firmware framebuffer\n");
			}
		}
	}
}

static int __screen_info_lfb_pci_bus_region(const struct screen_info *si, unsigned int type,
					    struct pci_bus_region *r)
{
	u64 base, size;

	base = __screen_info_lfb_base(si);
	if (!base)
		return -EINVAL;

	size = __screen_info_lfb_size(si, type);
	if (!size)
		return -EINVAL;

	r->start = base;
	r->end = base + size - 1;

	return 0;
}

static void screen_info_fixup_lfb(struct pci_dev *pdev)
{
	unsigned int type;
	struct pci_bus_region bus_region;
	int ret;
	struct resource r = {
		.flags = IORESOURCE_MEM,
	};
	const struct resource *pr;
	const struct screen_info *si = &sysfb_primary_display.screen;

	if (screen_info_lfb_pdev)
		return; // already found

	type = screen_info_video_type(si);
	if (!__screen_info_has_lfb(type))
		return; // only applies to EFI; maybe VESA

	ret = __screen_info_lfb_pci_bus_region(si, type, &bus_region);
	if (ret < 0)
		return;

	/*
	 * Translate the PCI bus address to resource. Account
	 * for an offset if the framebuffer is behind a PCI host
	 * bridge.
	 */
	pcibios_bus_to_resource(pdev->bus, &r, &bus_region);

	pr = pci_find_resource(pdev, &r);
	if (!pr)
		return;

	/*
	 * We've found a PCI device with the framebuffer
	 * resource. Store away the parameters to track
	 * relocation of the framebuffer aperture.
	 */
	screen_info_lfb_pdev = pdev;
	screen_info_lfb_bar = pr - pdev->resource;
	screen_info_lfb_offset = r.start - pr->start;
	screen_info_lfb_res_start = bus_region.start;
}
DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_ANY_ID, PCI_ANY_ID, PCI_BASE_CLASS_DISPLAY, 16,
			       screen_info_fixup_lfb);

static struct pci_dev *__screen_info_pci_dev(struct resource *res)
{
	struct pci_dev *pdev = NULL;
	const struct resource *r = NULL;

	if (!(res->flags & IORESOURCE_MEM))
		return NULL;

	while (!r && (pdev = pci_get_base_class(PCI_BASE_CLASS_DISPLAY, pdev))) {

Annotation

Implementation Notes