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78aa89d1df
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 55d728a40d ("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
137 lines
3.5 KiB
C
137 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/pci.h>
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#include <linux/printk.h>
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#include <linux/screen_info.h>
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#include <linux/string.h>
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static struct pci_dev *screen_info_lfb_pdev;
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static size_t screen_info_lfb_bar;
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static resource_size_t screen_info_lfb_offset;
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static struct resource screen_info_lfb_res = DEFINE_RES_MEM(0, 0);
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static bool __screen_info_relocation_is_valid(const struct screen_info *si, struct resource *pr)
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{
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u64 size = __screen_info_lfb_size(si, screen_info_video_type(si));
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if (screen_info_lfb_offset > resource_size(pr))
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return false;
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if (size > resource_size(pr))
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return false;
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if (resource_size(pr) - size < screen_info_lfb_offset)
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return false;
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return true;
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}
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void screen_info_apply_fixups(void)
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{
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struct screen_info *si = &screen_info;
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if (screen_info_lfb_pdev) {
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struct resource *pr = &screen_info_lfb_pdev->resource[screen_info_lfb_bar];
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if (pr->start != screen_info_lfb_res.start) {
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if (__screen_info_relocation_is_valid(si, pr)) {
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/*
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* Only update base if we have an actual
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* relocation to a valid I/O range.
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*/
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__screen_info_set_lfb_base(si, pr->start + screen_info_lfb_offset);
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pr_info("Relocating firmware framebuffer to offset %pa[d] within %pr\n",
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&screen_info_lfb_offset, pr);
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} else {
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pr_warn("Invalid relocating, disabling firmware framebuffer\n");
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}
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}
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}
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}
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static void screen_info_fixup_lfb(struct pci_dev *pdev)
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{
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unsigned int type;
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struct resource res[SCREEN_INFO_MAX_RESOURCES];
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size_t i, numres;
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int ret;
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const struct screen_info *si = &screen_info;
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if (screen_info_lfb_pdev)
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return; // already found
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type = screen_info_video_type(si);
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if (type != VIDEO_TYPE_EFI)
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return; // only applies to EFI
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ret = screen_info_resources(si, res, ARRAY_SIZE(res));
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if (ret < 0)
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return;
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numres = ret;
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for (i = 0; i < numres; ++i) {
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struct resource *r = &res[i];
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const struct resource *pr;
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if (!(r->flags & IORESOURCE_MEM))
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continue;
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pr = pci_find_resource(pdev, r);
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if (!pr)
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continue;
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/*
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* We've found a PCI device with the framebuffer
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* resource. Store away the parameters to track
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* relocation of the framebuffer aperture.
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*/
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screen_info_lfb_pdev = pdev;
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screen_info_lfb_bar = pr - pdev->resource;
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screen_info_lfb_offset = r->start - pr->start;
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memcpy(&screen_info_lfb_res, r, sizeof(screen_info_lfb_res));
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}
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}
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DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_ANY_ID, PCI_ANY_ID, PCI_BASE_CLASS_DISPLAY, 16,
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screen_info_fixup_lfb);
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static struct pci_dev *__screen_info_pci_dev(struct resource *res)
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{
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struct pci_dev *pdev = NULL;
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const struct resource *r = NULL;
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if (!(res->flags & IORESOURCE_MEM))
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return NULL;
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while (!r && (pdev = pci_get_base_class(PCI_BASE_CLASS_DISPLAY, pdev))) {
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r = pci_find_resource(pdev, res);
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}
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return pdev;
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}
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/**
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* screen_info_pci_dev() - Return PCI parent device that contains screen_info's framebuffer
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* @si: the screen_info
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*
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* Returns:
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* The screen_info's parent device or NULL on success, or a pointer-encoded
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* errno value otherwise. The value NULL is not an error. It signals that no
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* PCI device has been found.
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*/
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struct pci_dev *screen_info_pci_dev(const struct screen_info *si)
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{
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struct resource res[SCREEN_INFO_MAX_RESOURCES];
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ssize_t i, numres;
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numres = screen_info_resources(si, res, ARRAY_SIZE(res));
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if (numres < 0)
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return ERR_PTR(numres);
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for (i = 0; i < numres; ++i) {
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struct pci_dev *pdev = __screen_info_pci_dev(&res[i]);
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if (pdev)
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return pdev;
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}
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return NULL;
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}
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EXPORT_SYMBOL(screen_info_pci_dev);
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