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authorThomas Zimmermann <tzimmermann@suse.de>2024-02-12 10:06:15 +0100
committerThomas Zimmermann <tzimmermann@suse.de>2024-02-14 10:09:21 +0100
commit78aa89d1dfba1e3cf4a2e053afa3b4c4ec622371 (patch)
tree5329f0fbf2d241600d9d4b46ca57c13a54e1dcbd /drivers/video/screen_info_pci.c
parent784e27f2811884ab78edc713a4ef0d4deca9b668 (diff)
firmware/sysfb: Update screen_info for relocated EFI framebuffers
On ARM PCI systems, the PCI hierarchy might be reconfigured during boot and the firmware framebuffer might move as a result of that. The values in screen_info will then be invalid. Work around this problem by tracking the framebuffer's initial location before it get relocated; then fix the screen_info state between reloaction and creating the firmware framebuffer's device. This functionality has been lifted from efifb. See the commit message of commit 55d728a40d36 ("efi/fb: Avoid reconfiguration of BAR that covers the framebuffer") for more information. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20240212090736.11464-8-tzimmermann@suse.de
Diffstat (limited to 'drivers/video/screen_info_pci.c')
-rw-r--r--drivers/video/screen_info_pci.c88
1 files changed, 88 insertions, 0 deletions
diff --git a/drivers/video/screen_info_pci.c b/drivers/video/screen_info_pci.c
index d8985a54ce71..6c5833517141 100644
--- a/drivers/video/screen_info_pci.c
+++ b/drivers/video/screen_info_pci.c
@@ -1,7 +1,95 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/pci.h>
+#include <linux/printk.h>
#include <linux/screen_info.h>
+#include <linux/string.h>
+
+static struct pci_dev *screen_info_lfb_pdev;
+static size_t screen_info_lfb_bar;
+static resource_size_t screen_info_lfb_offset;
+static struct resource screen_info_lfb_res = DEFINE_RES_MEM(0, 0);
+
+static bool __screen_info_relocation_is_valid(const struct screen_info *si, struct resource *pr)
+{
+ u64 size = __screen_info_lfb_size(si, screen_info_video_type(si));
+
+ if (screen_info_lfb_offset > resource_size(pr))
+ return false;
+ if (size > resource_size(pr))
+ return false;
+ if (resource_size(pr) - size < screen_info_lfb_offset)
+ return false;
+
+ return true;
+}
+
+void screen_info_apply_fixups(void)
+{
+ struct screen_info *si = &screen_info;
+
+ if (screen_info_lfb_pdev) {
+ struct resource *pr = &screen_info_lfb_pdev->resource[screen_info_lfb_bar];
+
+ 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 void screen_info_fixup_lfb(struct pci_dev *pdev)
+{
+ unsigned int type;
+ struct resource res[SCREEN_INFO_MAX_RESOURCES];
+ size_t i, numres;
+ int ret;
+ const struct screen_info *si = &screen_info;
+
+ if (screen_info_lfb_pdev)
+ return; // already found
+
+ type = screen_info_video_type(si);
+ if (type != VIDEO_TYPE_EFI)
+ return; // only applies to EFI
+
+ ret = screen_info_resources(si, res, ARRAY_SIZE(res));
+ if (ret < 0)
+ return;
+ numres = ret;
+
+ for (i = 0; i < numres; ++i) {
+ struct resource *r = &res[i];
+ const struct resource *pr;
+
+ if (!(r->flags & IORESOURCE_MEM))
+ continue;
+ pr = pci_find_resource(pdev, r);
+ if (!pr)
+ continue;
+
+ /*
+ * 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;
+ memcpy(&screen_info_lfb_res, r, sizeof(screen_info_lfb_res));
+ }
+}
+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)
{