From 78aa89d1dfba1e3cf4a2e053afa3b4c4ec622371 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Mon, 12 Feb 2024 10:06:15 +0100 Subject: [PATCH] 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 Reviewed-by: Javier Martinez Canillas Link: https://patchwork.freedesktop.org/patch/msgid/20240212090736.11464-8-tzimmermann@suse.de --- drivers/firmware/sysfb.c | 2 + drivers/video/screen_info_pci.c | 88 +++++++++++++++++++++++++++++++++ include/linux/screen_info.h | 16 ++++++ 3 files changed, 106 insertions(+) diff --git a/drivers/firmware/sysfb.c b/drivers/firmware/sysfb.c index 170b7cd0cfcb..a6b48703dc9e 100644 --- a/drivers/firmware/sysfb.c +++ b/drivers/firmware/sysfb.c @@ -118,6 +118,8 @@ static __init int sysfb_init(void) bool compatible; int ret = 0; + screen_info_apply_fixups(); + mutex_lock(&disable_lock); if (disabled) goto unlock_mutex; 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 +#include #include +#include + +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) { diff --git a/include/linux/screen_info.h b/include/linux/screen_info.h index 0eae08e3c6f9..75303c126285 100644 --- a/include/linux/screen_info.h +++ b/include/linux/screen_info.h @@ -4,6 +4,8 @@ #include +#include + /** * SCREEN_INFO_MAX_RESOURCES - maximum number of resources per screen_info */ @@ -27,6 +29,17 @@ static inline u64 __screen_info_lfb_base(const struct screen_info *si) return lfb_base; } +static inline void __screen_info_set_lfb_base(struct screen_info *si, u64 lfb_base) +{ + si->lfb_base = lfb_base & GENMASK_ULL(31, 0); + si->ext_lfb_base = (lfb_base & GENMASK_ULL(63, 32)) >> 32; + + if (si->ext_lfb_base) + si->capabilities |= VIDEO_CAPABILITY_64BIT_BASE; + else + si->capabilities &= ~VIDEO_CAPABILITY_64BIT_BASE; +} + static inline u64 __screen_info_lfb_size(const struct screen_info *si, unsigned int type) { u64 lfb_size = si->lfb_size; @@ -106,8 +119,11 @@ static inline unsigned int screen_info_video_type(const struct screen_info *si) ssize_t screen_info_resources(const struct screen_info *si, struct resource *r, size_t num); #if defined(CONFIG_PCI) +void screen_info_apply_fixups(void); struct pci_dev *screen_info_pci_dev(const struct screen_info *si); #else +static inline void screen_info_apply_fixups(void) +{ } static inline struct pci_dev *screen_info_pci_dev(const struct screen_info *si) { return NULL;