Commit 9a45ac23 authored by Alex Deucher's avatar Alex Deucher
Browse files

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: default avatarAlex Deucher <alexander.deucher@amd.com>
parent eaa09053

drivers/video/fbdev/core/fbmem.c

+47 −0
Original line number Diff line number Diff line
@@ -1762,6 +1762,53 @@ 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

include/linux/fb.h

+1 −0
Original line number Diff line number Diff line
@@ -610,6 +610,7 @@ extern int remove_conflicting_pci_framebuffers(struct pci_dev *pdev, 
					       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);