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1// SPDX-License-Identifier: GPL-2.02 3#include <linux/pci.h>4#include <linux/printk.h>5#include <linux/screen_info.h>6#include <linux/string.h>7 8static struct pci_dev *screen_info_lfb_pdev;9static size_t screen_info_lfb_bar;10static resource_size_t screen_info_lfb_offset;11static struct resource screen_info_lfb_res = DEFINE_RES_MEM(0, 0);12 13static bool __screen_info_relocation_is_valid(const struct screen_info *si, struct resource *pr)14{15 u64 size = __screen_info_lfb_size(si, screen_info_video_type(si));16 17 if (screen_info_lfb_offset > resource_size(pr))18 return false;19 if (size > resource_size(pr))20 return false;21 if (resource_size(pr) - size < screen_info_lfb_offset)22 return false;23 24 return true;25}26 27void screen_info_apply_fixups(void)28{29 struct screen_info *si = &screen_info;30 31 if (screen_info_lfb_pdev) {32 struct resource *pr = &screen_info_lfb_pdev->resource[screen_info_lfb_bar];33 34 if (pr->start != screen_info_lfb_res.start) {35 if (__screen_info_relocation_is_valid(si, pr)) {36 /*37 * Only update base if we have an actual38 * relocation to a valid I/O range.39 */40 __screen_info_set_lfb_base(si, pr->start + screen_info_lfb_offset);41 pr_info("Relocating firmware framebuffer to offset %pa[d] within %pr\n",42 &screen_info_lfb_offset, pr);43 } else {44 pr_warn("Invalid relocating, disabling firmware framebuffer\n");45 }46 }47 }48}49 50static void screen_info_fixup_lfb(struct pci_dev *pdev)51{52 unsigned int type;53 struct resource res[SCREEN_INFO_MAX_RESOURCES];54 size_t i, numres;55 int ret;56 const struct screen_info *si = &screen_info;57 58 if (screen_info_lfb_pdev)59 return; // already found60 61 type = screen_info_video_type(si);62 if (type != VIDEO_TYPE_EFI)63 return; // only applies to EFI64 65 ret = screen_info_resources(si, res, ARRAY_SIZE(res));66 if (ret < 0)67 return;68 numres = ret;69 70 for (i = 0; i < numres; ++i) {71 struct resource *r = &res[i];72 const struct resource *pr;73 74 if (!(r->flags & IORESOURCE_MEM))75 continue;76 pr = pci_find_resource(pdev, r);77 if (!pr)78 continue;79 80 /*81 * We've found a PCI device with the framebuffer82 * resource. Store away the parameters to track83 * relocation of the framebuffer aperture.84 */85 screen_info_lfb_pdev = pdev;86 screen_info_lfb_bar = pr - pdev->resource;87 screen_info_lfb_offset = r->start - pr->start;88 memcpy(&screen_info_lfb_res, r, sizeof(screen_info_lfb_res));89 }90}91DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_ANY_ID, PCI_ANY_ID, PCI_BASE_CLASS_DISPLAY, 16,92 screen_info_fixup_lfb);93 94static struct pci_dev *__screen_info_pci_dev(struct resource *res)95{96 struct pci_dev *pdev = NULL;97 const struct resource *r = NULL;98 99 if (!(res->flags & IORESOURCE_MEM))100 return NULL;101 102 while (!r && (pdev = pci_get_base_class(PCI_BASE_CLASS_DISPLAY, pdev))) {103 r = pci_find_resource(pdev, res);104 }105 106 return pdev;107}108 109/**110 * screen_info_pci_dev() - Return PCI parent device that contains screen_info's framebuffer111 * @si: the screen_info112 *113 * Returns:114 * The screen_info's parent device or NULL on success, or a pointer-encoded115 * errno value otherwise. The value NULL is not an error. It signals that no116 * PCI device has been found.117 */118struct pci_dev *screen_info_pci_dev(const struct screen_info *si)119{120 struct resource res[SCREEN_INFO_MAX_RESOURCES];121 ssize_t i, numres;122 123 numres = screen_info_resources(si, res, ARRAY_SIZE(res));124 if (numres < 0)125 return ERR_PTR(numres);126 127 for (i = 0; i < numres; ++i) {128 struct pci_dev *pdev = __screen_info_pci_dev(&res[i]);129 130 if (pdev)131 return pdev;132 }133 134 return NULL;135}136EXPORT_SYMBOL(screen_info_pci_dev);137