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authorAlex Deucher <alexander.deucher@amd.com>2021-12-22 22:41:18 -0500
committerAlex Deucher <alexander.deucher@amd.com>2021-12-31 08:57:45 -0500
commit9a45ac2320d0a6ae01880a30d4b86025fce4061b (patch)
tree99046d1e82c89d6ada5ba24bcd99bc44cbe544b6 /drivers/video/fbdev
parenteaa090538e8d21801c6d5f94590c3799e6a528b5 (diff)
downloadlinux-9a45ac2320d0a6ae01880a30d4b86025fce4061b.tar.bz2
fbdev: fbmem: add a helper to determine if an aperture is used by a fw fb
Add a function for drivers to check if the a firmware initialized fb is corresponds to their aperture. This allows drivers to check if the device corresponds to what the firmware set up as the display device. Bug: https://bugzilla.kernel.org/show_bug.cgi?id=215203 Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1840 Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers/video/fbdev')
-rw-r--r--drivers/video/fbdev/core/fbmem.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 826175ad88a2..0fa7ede94fa6 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1763,6 +1763,53 @@ int remove_conflicting_framebuffers(struct apertures_struct *a,
EXPORT_SYMBOL(remove_conflicting_framebuffers);
/**
+ * is_firmware_framebuffer - detect if firmware-configured framebuffer matches
+ * @a: memory range, users of which are to be checked
+ *
+ * This function checks framebuffer devices (initialized by firmware/bootloader)
+ * which use memory range described by @a. If @a matchesm the function returns
+ * true, otherwise false.
+ */
+bool is_firmware_framebuffer(struct apertures_struct *a)
+{
+ bool do_free = false;
+ bool found = false;
+ int i;
+
+ if (!a) {
+ a = alloc_apertures(1);
+ if (!a)
+ return false;
+
+ a->ranges[0].base = 0;
+ a->ranges[0].size = ~0;
+ do_free = true;
+ }
+
+ mutex_lock(&registration_lock);
+ /* check all firmware fbs and kick off if the base addr overlaps */
+ for_each_registered_fb(i) {
+ struct apertures_struct *gen_aper;
+
+ if (!(registered_fb[i]->flags & FBINFO_MISC_FIRMWARE))
+ continue;
+
+ gen_aper = registered_fb[i]->apertures;
+ if (fb_do_apertures_overlap(gen_aper, a)) {
+ found = true;
+ break;
+ }
+ }
+ mutex_unlock(&registration_lock);
+
+ if (do_free)
+ kfree(a);
+
+ return found;
+}
+EXPORT_SYMBOL(is_firmware_framebuffer);
+
+/**
* remove_conflicting_pci_framebuffers - remove firmware-configured framebuffers for PCI devices
* @pdev: PCI device
* @name: requesting driver name