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path: root/drivers/video/screen_info_pci.c
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Diffstat (limited to 'drivers/video/screen_info_pci.c')
-rw-r--r--drivers/video/screen_info_pci.c136
1 files changed, 136 insertions, 0 deletions
diff --git a/drivers/video/screen_info_pci.c b/drivers/video/screen_info_pci.c
new file mode 100644
index 0000000000..6c58335171
--- /dev/null
+++ b/drivers/video/screen_info_pci.c
@@ -0,0 +1,136 @@
+// 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)
+{
+ 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))) {
+ r = pci_find_resource(pdev, res);
+ }
+
+ return pdev;
+}
+
+/**
+ * screen_info_pci_dev() - Return PCI parent device that contains screen_info's framebuffer
+ * @si: the screen_info
+ *
+ * Returns:
+ * The screen_info's parent device or NULL on success, or a pointer-encoded
+ * errno value otherwise. The value NULL is not an error. It signals that no
+ * PCI device has been found.
+ */
+struct pci_dev *screen_info_pci_dev(const struct screen_info *si)
+{
+ struct resource res[SCREEN_INFO_MAX_RESOURCES];
+ ssize_t i, numres;
+
+ numres = screen_info_resources(si, res, ARRAY_SIZE(res));
+ if (numres < 0)
+ return ERR_PTR(numres);
+
+ for (i = 0; i < numres; ++i) {
+ struct pci_dev *pdev = __screen_info_pci_dev(&res[i]);
+
+ if (pdev)
+ return pdev;
+ }
+
+ return NULL;
+}
+EXPORT_SYMBOL(screen_info_pci_dev);