From: Alex Deucher alexander.deucher@amd.com
commit 9a45ac2320d0a6ae01880a30d4b86025fce4061b upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/video/fbdev/core/fbmem.c | 47 +++++++++++++++++++++++++++++++++++++++ include/linux/fb.h | 1 2 files changed, 48 insertions(+)
--- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1760,6 +1760,53 @@ int remove_conflicting_framebuffers(stru 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(®istration_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(®istration_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 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -610,6 +610,7 @@ extern int remove_conflicting_pci_frameb const char *name); extern int remove_conflicting_framebuffers(struct apertures_struct *a, const char *name, bool primary); +extern bool is_firmware_framebuffer(struct apertures_struct *a); extern int fb_prepare_logo(struct fb_info *fb_info, int rotate); extern int fb_show_logo(struct fb_info *fb_info, int rotate); extern char* fb_get_buffer_offset(struct fb_info *info, struct fb_pixmap *buf, u32 size);