xref: /linux-6.12.1/drivers/video/fbdev/efifb.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Framebuffer driver for EFI/UEFI based system
 *
 * (c) 2006 Edgar Hucek <gimli@dark-green.com>
 * Original efi driver written by Gerd Knorr <kraxel@goldbach.in-berlin.de>
 *
 */

#include <linux/aperture.h>
#include <linux/kernel.h>
#include <linux/efi.h>
#include <linux/efi-bgrt.h>
#include <linux/errno.h>
#include <linux/fb.h>
#include <linux/platform_device.h>
#include <linux/printk.h>
#include <linux/screen_info.h>
#include <video/vga.h>
#include <asm/efi.h>
#include <drm/drm_utils.h> /* For drm_get_panel_orientation_quirk */
#include <drm/drm_connector.h>  /* For DRM_MODE_PANEL_ORIENTATION_* */

struct bmp_file_header {
	u16 id;
	u32 file_size;
	u32 reserved;
	u32 bitmap_offset;
} __packed;

struct bmp_dib_header {
	u32 dib_header_size;
	s32 width;
	s32 height;
	u16 planes;
	u16 bpp;
	u32 compression;
	u32 bitmap_size;
	u32 horz_resolution;
	u32 vert_resolution;
	u32 colors_used;
	u32 colors_important;
} __packed;

static bool use_bgrt = true;
static bool request_mem_succeeded = false;
static u64 mem_flags = EFI_MEMORY_WC | EFI_MEMORY_UC;

struct efifb_par {
	u32 pseudo_palette[16];
	resource_size_t base;
	resource_size_t size;
};

static struct fb_var_screeninfo efifb_defined = {
	.activate		= FB_ACTIVATE_NOW,
	.height			= -1,
	.width			= -1,
	.right_margin		= 32,
	.upper_margin		= 16,
	.lower_margin		= 4,
	.vsync_len		= 4,
	.vmode			= FB_VMODE_NONINTERLACED,
};

static struct fb_fix_screeninfo efifb_fix = {
	.id			= "EFI VGA",
	.type			= FB_TYPE_PACKED_PIXELS,
	.accel			= FB_ACCEL_NONE,
	.visual			= FB_VISUAL_TRUECOLOR,
};

static int efifb_setcolreg(unsigned regno, unsigned red, unsigned green,
			   unsigned blue, unsigned transp,
			   struct fb_info *info)
{
	/*
	 *  Set a single color register. The values supplied are
	 *  already rounded down to the hardware's capabilities
	 *  (according to the entries in the `var' structure). Return
	 *  != 0 for invalid regno.
	 */

	if (regno >= info->cmap.len)
		return 1;

	if (regno < 16) {
		red   >>= 16 - info->var.red.length;
		green >>= 16 - info->var.green.length;
		blue  >>= 16 - info->var.blue.length;
		((u32 *)(info->pseudo_palette))[regno] =
			(red   << info->var.red.offset)   |
			(green << info->var.green.offset) |
			(blue  << info->var.blue.offset);
	}
	return 0;
}

/*
 * If fbcon deffered console takeover is configured, the intent is for the
 * framebuffer to show the boot graphics (e.g. vendor logo) until there is some
 * (error) message to display. But the boot graphics may have been destroyed by
 * e.g. option ROM output, detect this and restore the boot graphics.
 */
#if defined CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER && \
    defined CONFIG_ACPI_BGRT
static void efifb_copy_bmp(u8 *src, u32 *dst, int width, const struct screen_info *si)
{
	u8 r, g, b;

	while (width--) {
		b = *src++;
		g = *src++;
		r = *src++;
		*dst++ = (r << si->red_pos)   |
			 (g << si->green_pos) |
			 (b << si->blue_pos);
	}
}

#ifdef CONFIG_X86
/*
 * On x86 some firmwares use a low non native resolution for the display when
 * they have shown some text messages. While keeping the bgrt filled with info
 * for the native resolution. If the bgrt image intended for the native
 * resolution still fits, it will be displayed very close to the right edge of
 * the display looking quite bad. This function checks for this.
 */
static bool efifb_bgrt_sanity_check(const struct screen_info *si, u32 bmp_width)
{
	/*
	 * All x86 firmwares horizontally center the image (the yoffset
	 * calculations differ between boards, but xoffset is predictable).
	 */
	u32 expected_xoffset = (si->lfb_width - bmp_width) / 2;

	return bgrt_tab.image_offset_x == expected_xoffset;
}
#else
static bool efifb_bgrt_sanity_check(const struct screen_info *si, u32 bmp_width)
{
	return true;
}
#endif

static void efifb_show_boot_graphics(struct fb_info *info, const struct screen_info *si)
{
	u32 bmp_width, bmp_height, bmp_pitch, dst_x, y, src_y;
	struct bmp_file_header *file_header;
	struct bmp_dib_header *dib_header;
	void *bgrt_image = NULL;
	u8 *dst = info->screen_base;

	if (!use_bgrt)
		return;

	if (!bgrt_tab.image_address) {
		pr_info("efifb: No BGRT, not showing boot graphics\n");
		return;
	}

	if (bgrt_tab.status & 0x06) {
		pr_info("efifb: BGRT rotation bits set, not showing boot graphics\n");
		return;
	}

	/* Avoid flashing the logo if we're going to print std probe messages */
	if (console_loglevel > CONSOLE_LOGLEVEL_QUIET)
		return;

	/* bgrt_tab.status is unreliable, so we don't check it */

	if (si->lfb_depth != 32) {
		pr_info("efifb: not 32 bits, not showing boot graphics\n");
		return;
	}

	bgrt_image = memremap(bgrt_tab.image_address, bgrt_image_size,
			      MEMREMAP_WB);
	if (!bgrt_image) {
		pr_warn("efifb: Ignoring BGRT: failed to map image memory\n");
		return;
	}

	if (bgrt_image_size < (sizeof(*file_header) + sizeof(*dib_header)))
		goto error;

	file_header = bgrt_image;
	if (file_header->id != 0x4d42 || file_header->reserved != 0)
		goto error;

	dib_header = bgrt_image + sizeof(*file_header);
	if (dib_header->dib_header_size != 40 || dib_header->width < 0 ||
	    dib_header->planes != 1 || dib_header->bpp != 24 ||
	    dib_header->compression != 0)
		goto error;

	bmp_width = dib_header->width;
	bmp_height = abs(dib_header->height);
	bmp_pitch = round_up(3 * bmp_width, 4);

	if ((file_header->bitmap_offset + bmp_pitch * bmp_height) >
				bgrt_image_size)
		goto error;

	if ((bgrt_tab.image_offset_x + bmp_width) > si->lfb_width ||
	    (bgrt_tab.image_offset_y + bmp_height) > si->lfb_height)
		goto error;

	if (!efifb_bgrt_sanity_check(si, bmp_width))
		goto error;

	pr_info("efifb: showing boot graphics\n");

	for (y = 0; y < si->lfb_height; y++, dst += si->lfb_linelength) {
		/* Only background? */
		if (y < bgrt_tab.image_offset_y ||
		    y >= (bgrt_tab.image_offset_y + bmp_height)) {
			memset(dst, 0, 4 * si->lfb_width);
			continue;
		}

		src_y = y - bgrt_tab.image_offset_y;
		/* Positive header height means upside down row order */
		if (dib_header->height > 0)
			src_y = (bmp_height - 1) - src_y;

		memset(dst, 0, bgrt_tab.image_offset_x * 4);
		dst_x = bgrt_tab.image_offset_x;
		efifb_copy_bmp(bgrt_image + file_header->bitmap_offset +
					    src_y * bmp_pitch,
			       (u32 *)dst + dst_x, bmp_width, si);
		dst_x += bmp_width;
		memset((u32 *)dst + dst_x, 0, (si->lfb_width - dst_x) * 4);
	}

	memunmap(bgrt_image);
	return;

error:
	memunmap(bgrt_image);
	pr_warn("efifb: Ignoring BGRT: unexpected or invalid BMP data\n");
}
#else
static inline void efifb_show_boot_graphics(struct fb_info *info, const struct screen_info *si)
{ }
#endif

/*
 * fb_ops.fb_destroy is called by the last put_fb_info() call at the end
 * of unregister_framebuffer() or fb_release(). Do any cleanup here.
 */
static void efifb_destroy(struct fb_info *info)
{
	struct efifb_par *par = info->par;

	if (info->screen_base) {
		if (mem_flags & (EFI_MEMORY_UC | EFI_MEMORY_WC))
			iounmap(info->screen_base);
		else
			memunmap(info->screen_base);
	}

	if (request_mem_succeeded)
		release_mem_region(par->base, par->size);
	fb_dealloc_cmap(&info->cmap);

	framebuffer_release(info);
}

static const struct fb_ops efifb_ops = {
	.owner		= THIS_MODULE,
	FB_DEFAULT_IOMEM_OPS,
	.fb_destroy	= efifb_destroy,
	.fb_setcolreg	= efifb_setcolreg,
};

static int efifb_setup(struct screen_info *si, char *options)
{
	char *this_opt;

	if (options && *options) {
		while ((this_opt = strsep(&options, ",")) != NULL) {
			if (!*this_opt) continue;

			efifb_setup_from_dmi(si, this_opt);

			if (!strncmp(this_opt, "base:", 5))
				si->lfb_base = simple_strtoul(this_opt+5, NULL, 0);
			else if (!strncmp(this_opt, "stride:", 7))
				si->lfb_linelength = simple_strtoul(this_opt+7, NULL, 0) * 4;
			else if (!strncmp(this_opt, "height:", 7))
				si->lfb_height = simple_strtoul(this_opt+7, NULL, 0);
			else if (!strncmp(this_opt, "width:", 6))
				si->lfb_width = simple_strtoul(this_opt+6, NULL, 0);
			else if (!strcmp(this_opt, "nowc"))
				mem_flags &= ~EFI_MEMORY_WC;
			else if (!strcmp(this_opt, "nobgrt"))
				use_bgrt = false;
		}
	}

	return 0;
}

static inline bool fb_base_is_valid(struct screen_info *si)
{
	if (si->lfb_base)
		return true;

	if (!(si->capabilities & VIDEO_CAPABILITY_64BIT_BASE))
		return false;

	if (si->ext_lfb_base)
		return true;

	return false;
}

#define efifb_attr_decl(name, fmt)					\
static ssize_t name##_show(struct device *dev,				\
			   struct device_attribute *attr,		\
			   char *buf)					\
{									\
	struct screen_info *si = dev_get_drvdata(dev);			\
	if (!si)							\
		return -ENODEV;						\
	return sprintf(buf, fmt "\n", (si->lfb_##name));		\
}									\
static DEVICE_ATTR_RO(name)

efifb_attr_decl(base, "0x%x");
efifb_attr_decl(linelength, "%u");
efifb_attr_decl(height, "%u");
efifb_attr_decl(width, "%u");
efifb_attr_decl(depth, "%u");

static struct attribute *efifb_attrs[] = {
	&dev_attr_base.attr,
	&dev_attr_linelength.attr,
	&dev_attr_width.attr,
	&dev_attr_height.attr,
	&dev_attr_depth.attr,
	NULL
};
ATTRIBUTE_GROUPS(efifb);

static int efifb_probe(struct platform_device *dev)
{
	struct screen_info *si;
	struct fb_info *info;
	struct efifb_par *par;
	int err, orientation;
	unsigned int size_vmode;
	unsigned int size_remap;
	unsigned int size_total;
	char *option = NULL;
	efi_memory_desc_t md;

	/*
	 * If we fail probing the device, the kernel might try a different
	 * driver. We get a copy of the attached screen_info, so that we can
	 * modify its values without affecting later drivers.
	 */
	si = dev_get_platdata(&dev->dev);
	if (!si)
		return -ENODEV;
	si = devm_kmemdup(&dev->dev, si, sizeof(*si), GFP_KERNEL);
	if (!si)
		return -ENOMEM;

	dev_set_drvdata(&dev->dev, si);

	if (si->orig_video_isVGA != VIDEO_TYPE_EFI)
		return -ENODEV;

	if (fb_get_options("efifb", &option))
		return -ENODEV;
	efifb_setup(si, option);

	/* We don't get linelength from UGA Draw Protocol, only from
	 * EFI Graphics Protocol.  So if it's not in DMI, and it's not
	 * passed in from the user, we really can't use the framebuffer.
	 */
	if (!si->lfb_linelength)
		return -ENODEV;

	if (!si->lfb_depth)
		si->lfb_depth = 32;
	if (!si->pages)
		si->pages = 1;
	if (!fb_base_is_valid(si)) {
		printk(KERN_DEBUG "efifb: invalid framebuffer address\n");
		return -ENODEV;
	}
	printk(KERN_INFO "efifb: probing for efifb\n");

	/* just assume they're all unset if any are */
	if (!si->blue_size) {
		si->blue_size = 8;
		si->blue_pos = 0;
		si->green_size = 8;
		si->green_pos = 8;
		si->red_size = 8;
		si->red_pos = 16;
		si->rsvd_size = 8;
		si->rsvd_pos = 24;
	}

	efifb_fix.smem_start = __screen_info_lfb_base(si);

	efifb_defined.bits_per_pixel = si->lfb_depth;
	efifb_defined.xres = si->lfb_width;
	efifb_defined.yres = si->lfb_height;
	efifb_fix.line_length = si->lfb_linelength;

	/*   size_vmode -- that is the amount of memory needed for the
	 *                 used video mode, i.e. the minimum amount of
	 *                 memory we need. */
	size_vmode = efifb_defined.yres * efifb_fix.line_length;

	/*   size_total -- all video memory we have. Used for
	 *                 entries, ressource allocation and bounds
	 *                 checking. */
	size_total = si->lfb_size;
	if (size_total < size_vmode)
		size_total = size_vmode;

	/*   size_remap -- the amount of video memory we are going to
	 *                 use for efifb.  With modern cards it is no
	 *                 option to simply use size_total as that
	 *                 wastes plenty of kernel address space. */
	size_remap  = size_vmode * 2;
	if (size_remap > size_total)
		size_remap = size_total;
	if (size_remap % PAGE_SIZE)
		size_remap += PAGE_SIZE - (size_remap % PAGE_SIZE);
	efifb_fix.smem_len = size_remap;

	if (request_mem_region(efifb_fix.smem_start, size_remap, "efifb")) {
		request_mem_succeeded = true;
	} else {
		/* We cannot make this fatal. Sometimes this comes from magic
		   spaces our resource handlers simply don't know about */
		pr_warn("efifb: cannot reserve video memory at 0x%lx\n",
			efifb_fix.smem_start);
	}

	info = framebuffer_alloc(sizeof(*par), &dev->dev);
	if (!info) {
		err = -ENOMEM;
		goto err_release_mem;
	}
	par = info->par;
	info->pseudo_palette = par->pseudo_palette;

	par->base = efifb_fix.smem_start;
	par->size = size_remap;

	if (efi_enabled(EFI_MEMMAP) &&
	    !efi_mem_desc_lookup(efifb_fix.smem_start, &md)) {
		if ((efifb_fix.smem_start + efifb_fix.smem_len) >
		    (md.phys_addr + (md.num_pages << EFI_PAGE_SHIFT))) {
			pr_err("efifb: video memory @ 0x%lx spans multiple EFI memory regions\n",
			       efifb_fix.smem_start);
			err = -EIO;
			goto err_release_fb;
		}
		/*
		 * If the UEFI memory map covers the efifb region, we may only
		 * remap it using the attributes the memory map prescribes.
		 */
		md.attribute &= EFI_MEMORY_UC | EFI_MEMORY_WC |
				EFI_MEMORY_WT | EFI_MEMORY_WB;
		if (md.attribute) {
			mem_flags |= EFI_MEMORY_WT | EFI_MEMORY_WB;
			mem_flags &= md.attribute;
		}
	}
	if (mem_flags & EFI_MEMORY_WC)
		info->screen_base = ioremap_wc(efifb_fix.smem_start,
					       efifb_fix.smem_len);
	else if (mem_flags & EFI_MEMORY_UC)
		info->screen_base = ioremap(efifb_fix.smem_start,
					    efifb_fix.smem_len);
	else if (mem_flags & EFI_MEMORY_WT)
		info->screen_base = memremap(efifb_fix.smem_start,
					     efifb_fix.smem_len, MEMREMAP_WT);
	else if (mem_flags & EFI_MEMORY_WB)
		info->screen_base = memremap(efifb_fix.smem_start,
					     efifb_fix.smem_len, MEMREMAP_WB);
	if (!info->screen_base) {
		pr_err("efifb: abort, cannot remap video memory 0x%x @ 0x%lx\n",
			efifb_fix.smem_len, efifb_fix.smem_start);
		err = -EIO;
		goto err_release_fb;
	}

	efifb_show_boot_graphics(info, si);

	pr_info("efifb: framebuffer at 0x%lx, using %dk, total %dk\n",
	       efifb_fix.smem_start, size_remap/1024, size_total/1024);
	pr_info("efifb: mode is %dx%dx%d, linelength=%d, pages=%d\n",
	       efifb_defined.xres, efifb_defined.yres,
	       efifb_defined.bits_per_pixel, efifb_fix.line_length,
	       si->pages);

	efifb_defined.xres_virtual = efifb_defined.xres;
	efifb_defined.yres_virtual = efifb_fix.smem_len /
					efifb_fix.line_length;
	pr_info("efifb: scrolling: redraw\n");
	efifb_defined.yres_virtual = efifb_defined.yres;

	/* some dummy values for timing to make fbset happy */
	efifb_defined.pixclock     = 10000000 / efifb_defined.xres *
					1000 / efifb_defined.yres;
	efifb_defined.left_margin  = (efifb_defined.xres / 8) & 0xf8;
	efifb_defined.hsync_len    = (efifb_defined.xres / 8) & 0xf8;

	efifb_defined.red.offset    = si->red_pos;
	efifb_defined.red.length    = si->red_size;
	efifb_defined.green.offset  = si->green_pos;
	efifb_defined.green.length  = si->green_size;
	efifb_defined.blue.offset   = si->blue_pos;
	efifb_defined.blue.length   = si->blue_size;
	efifb_defined.transp.offset = si->rsvd_pos;
	efifb_defined.transp.length = si->rsvd_size;

	pr_info("efifb: %s: "
	       "size=%d:%d:%d:%d, shift=%d:%d:%d:%d\n",
	       "Truecolor",
	       si->rsvd_size,
	       si->red_size,
	       si->green_size,
	       si->blue_size,
	       si->rsvd_pos,
	       si->red_pos,
	       si->green_pos,
	       si->blue_pos);

	efifb_fix.ypanstep  = 0;
	efifb_fix.ywrapstep = 0;

	info->fbops = &efifb_ops;
	info->var = efifb_defined;
	info->fix = efifb_fix;

	orientation = drm_get_panel_orientation_quirk(efifb_defined.xres,
						      efifb_defined.yres);
	switch (orientation) {
	default:
		info->fbcon_rotate_hint = FB_ROTATE_UR;
		break;
	case DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP:
		info->fbcon_rotate_hint = FB_ROTATE_UD;
		break;
	case DRM_MODE_PANEL_ORIENTATION_LEFT_UP:
		info->fbcon_rotate_hint = FB_ROTATE_CCW;
		break;
	case DRM_MODE_PANEL_ORIENTATION_RIGHT_UP:
		info->fbcon_rotate_hint = FB_ROTATE_CW;
		break;
	}

	err = fb_alloc_cmap(&info->cmap, 256, 0);
	if (err < 0) {
		pr_err("efifb: cannot allocate colormap\n");
		goto err_unmap;
	}

	err = devm_aperture_acquire_for_platform_device(dev, par->base, par->size);
	if (err) {
		pr_err("efifb: cannot acquire aperture\n");
		goto err_fb_dealloc_cmap;
	}
	err = devm_register_framebuffer(&dev->dev, info);
	if (err < 0) {
		pr_err("efifb: cannot register framebuffer\n");
		goto err_fb_dealloc_cmap;
	}
	fb_info(info, "%s frame buffer device\n", info->fix.id);
	return 0;

err_fb_dealloc_cmap:
	fb_dealloc_cmap(&info->cmap);
err_unmap:
	if (mem_flags & (EFI_MEMORY_UC | EFI_MEMORY_WC))
		iounmap(info->screen_base);
	else
		memunmap(info->screen_base);
err_release_fb:
	framebuffer_release(info);
err_release_mem:
	if (request_mem_succeeded)
		release_mem_region(efifb_fix.smem_start, size_total);
	return err;
}

static struct platform_driver efifb_driver = {
	.driver = {
		.name = "efi-framebuffer",
		.dev_groups = efifb_groups,
	},
	.probe = efifb_probe,
};

builtin_platform_driver(efifb_driver);