text: // 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/kernel.h>
  #include <linux/efi.h>
  #include <linux/errno.h>
  #include <linux/fb.h>
  #include <linux/pci.h>
  #include <linux/platform_device.h>
  #include <linux/screen_info.h>
  #include <video/vga.h>
  #include <asm/efi.h>
  
  static bool request_mem_succeeded = false;
  static bool nowc = false;
  
  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;
  }
  
  static void efifb_destroy(struct fb_info *info)
  {
  	if (info->screen_base)
  		iounmap(info->screen_base);
  	if (request_mem_succeeded)
  		release_mem_region(info->apertures->ranges[0].base,
  				   info->apertures->ranges[0].size);
  	fb_dealloc_cmap(&info->cmap);
  }
  
  static struct fb_ops efifb_ops = {
  	.owner		= THIS_MODULE,
  	.fb_destroy	= efifb_destroy,
  	.fb_setcolreg	= efifb_setcolreg,
  	.fb_fillrect	= cfb_fillrect,
  	.fb_copyarea	= cfb_copyarea,
  	.fb_imageblit	= cfb_imageblit,
  };
  
  static int efifb_setup(char *options)
  {
  	char *this_opt;
  
  	if (options && *options) {
  		while ((this_opt = strsep(&options, ",")) != NULL) {
  			if (!*this_opt) continue;
  
  			efifb_setup_from_dmi(&screen_info, this_opt);
  
  			if (!strncmp(this_opt, "base:", 5))
  				screen_info.lfb_base = simple_strtoul(this_opt+5, NULL, 0);
  			else if (!strncmp(this_opt, "stride:", 7))
  				screen_info.lfb_linelength = simple_strtoul(this_opt+7, NULL, 0) * 4;
  			else if (!strncmp(this_opt, "height:", 7))
  				screen_info.lfb_height = simple_strtoul(this_opt+7, NULL, 0);
  			else if (!strncmp(this_opt, "width:", 6))
  				screen_info.lfb_width = simple_strtoul(this_opt+6, NULL, 0);
  			else if (!strcmp(this_opt, "nowc"))
  				nowc = true;
  		}
  	}
  
  	return 0;
  }
  
  static inline bool fb_base_is_valid(void)
  {
  	if (screen_info.lfb_base)
  		return true;
  
  	if (!(screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE))
  		return false;
  
  	if (screen_info.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)					\
  {									\
  	return sprintf(buf, fmt "\n", (screen_info.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 bool pci_dev_disabled;	/* FB base matches BAR of a disabled device */
  
  static struct pci_dev *efifb_pci_dev;	/* dev with BAR covering the efifb */
  static struct resource *bar_resource;
  static u64 bar_offset;
  
  static int efifb_probe(struct platform_device *dev)
  {
  	struct fb_info *info;
  	int err;
  	unsigned int size_vmode;
  	unsigned int size_remap;
  	unsigned int size_total;
  	char *option = NULL;
  
  	if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI || pci_dev_disabled)
  		return -ENODEV;
  
  	if (fb_get_options("efifb", &option))
  		return -ENODEV;
  	efifb_setup(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 (!screen_info.lfb_linelength)
  		return -ENODEV;
  
  	if (!screen_info.lfb_depth)
  		screen_info.lfb_depth = 32;
  	if (!screen_info.pages)
  		screen_info.pages = 1;
  	if (!fb_base_is_valid()) {
  		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 (!screen_info.blue_size) {
  		screen_info.blue_size = 8;
  		screen_info.blue_pos = 0;
  		screen_info.green_size = 8;
  		screen_info.green_pos = 8;
  		screen_info.red_size = 8;
  		screen_info.red_pos = 16;
  		screen_info.rsvd_size = 8;
  		screen_info.rsvd_pos = 24;
  	}
  
  	efifb_fix.smem_start = screen_info.lfb_base;
  
  	if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) {
  		u64 ext_lfb_base;
  
  		ext_lfb_base = (u64)(unsigned long)screen_info.ext_lfb_base << 32;
  		efifb_fix.smem_start |= ext_lfb_base;
  	}
  
  	if (bar_resource &&
  	    bar_resource->start + bar_offset != efifb_fix.smem_start) {
  		dev_info(&efifb_pci_dev->dev,
  			 "BAR has moved, updating efifb address\n");
  		efifb_fix.smem_start = bar_resource->start + bar_offset;
  	}
  
  	efifb_defined.bits_per_pixel = screen_info.lfb_depth;
  	efifb_defined.xres = screen_info.lfb_width;
  	efifb_defined.yres = screen_info.lfb_height;
  	efifb_fix.line_length = screen_info.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 = screen_info.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(u32) * 16, &dev->dev);
  	if (!info) {
  		pr_err("efifb: cannot allocate framebuffer\n");
  		err = -ENOMEM;
  		goto err_release_mem;
  	}
  	platform_set_drvdata(dev, info);
  	info->pseudo_palette = info->par;
  	info->par = NULL;
  
  	info->apertures = alloc_apertures(1);
  	if (!info->apertures) {
  		err = -ENOMEM;
  		goto err_release_fb;
  	}
  	info->apertures->ranges[0].base = efifb_fix.smem_start;
  	info->apertures->ranges[0].size = size_remap;
  
  	if (nowc)
  		info->screen_base = ioremap(efifb_fix.smem_start, efifb_fix.smem_len);
  	else
  		info->screen_base = ioremap_wc(efifb_fix.smem_start, efifb_fix.smem_len);
  	if (!info->screen_base) {
  		pr_err("efifb: abort, cannot ioremap video memory 0x%x @ 0x%lx\n",
  			efifb_fix.smem_len, efifb_fix.smem_start);
  		err = -EIO;
  		goto err_release_fb;
  	}
  
  	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,
  	       screen_info.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    = screen_info.red_pos;
  	efifb_defined.red.length    = screen_info.red_size;
  	efifb_defined.green.offset  = screen_info.green_pos;
  	efifb_defined.green.length  = screen_info.green_size;
  	efifb_defined.blue.offset   = screen_info.blue_pos;
  	efifb_defined.blue.length   = screen_info.blue_size;
  	efifb_defined.transp.offset = screen_info.rsvd_pos;
  	efifb_defined.transp.length = screen_info.rsvd_size;
  
  	pr_info("efifb: %s: "
  	       "size=%d:%d:%d:%d, shift=%d:%d:%d:%d\n",
  	       "Truecolor",
  	       screen_info.rsvd_size,
  	       screen_info.red_size,
  	       screen_info.green_size,
  	       screen_info.blue_size,
  	       screen_info.rsvd_pos,
  	       screen_info.red_pos,
  	       screen_info.green_pos,
  	       screen_info.blue_pos);
  
  	efifb_fix.ypanstep  = 0;
  	efifb_fix.ywrapstep = 0;
  
  	info->fbops = &efifb_ops;
  	info->var = efifb_defined;
  	info->fix = efifb_fix;
  	info->flags = FBINFO_FLAG_DEFAULT | FBINFO_MISC_FIRMWARE;
  
  	err = sysfs_create_groups(&dev->dev.kobj, efifb_groups);
  	if (err) {
  		pr_err("efifb: cannot add sysfs attrs\n");
  		goto err_unmap;
  	}
  	err = fb_alloc_cmap(&info->cmap, 256, 0);
  	if (err < 0) {
  		pr_err("efifb: cannot allocate colormap\n");
  		goto err_groups;
  	}
  	err = register_framebuffer(info);
  	if (err < 0) {
  		pr_err("efifb: cannot register framebuffer\n");
  		goto err_fb_dealoc;
  	}
  	fb_info(info, "%s frame buffer device\n", info->fix.id);
  	return 0;
  
  err_fb_dealoc:
  	fb_dealloc_cmap(&info->cmap);
  err_groups:
  	sysfs_remove_groups(&dev->dev.kobj, efifb_groups);
  err_unmap:
  	iounmap(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 int efifb_remove(struct platform_device *pdev)
  {
  	struct fb_info *info = platform_get_drvdata(pdev);
  
  	unregister_framebuffer(info);
  	sysfs_remove_groups(&pdev->dev.kobj, efifb_groups);
  	framebuffer_release(info);
  
  	return 0;
  }
  
  static struct platform_driver efifb_driver = {
  	.driver = {
  		.name = "efi-framebuffer",
  	},
  	.probe = efifb_probe,
  	.remove = efifb_remove,
  };
  
  builtin_platform_driver(efifb_driver);
  
  #if defined(CONFIG_PCI)
  
  static void record_efifb_bar_resource(struct pci_dev *dev, int idx, u64 offset)
  {
  	u16 word;
  
  	efifb_pci_dev = dev;
  
  	pci_read_config_word(dev, PCI_COMMAND, &word);
  	if (!(word & PCI_COMMAND_MEMORY)) {
  		pci_dev_disabled = true;
  		dev_err(&dev->dev,
  			"BAR %d: assigned to efifb but device is disabled!\n",
  			idx);
  		return;
  	}
  
  	bar_resource = &dev->resource[idx];
  	bar_offset = offset;
  
  	dev_info(&dev->dev, "BAR %d: assigned to efifb\n", idx);
  }
  
  static void efifb_fixup_resources(struct pci_dev *dev)
  {
  	u64 base = screen_info.lfb_base;
  	u64 size = screen_info.lfb_size;
  	int i;
  
  	if (efifb_pci_dev || screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
  		return;
  
  	if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
  		base |= (u64)screen_info.ext_lfb_base << 32;
  
  	if (!base)
  		return;
  
  	for (i = 0; i <= PCI_STD_RESOURCE_END; i++) {
  		struct resource *res = &dev->resource[i];
  
  		if (!(res->flags & IORESOURCE_MEM))
  			continue;
  
  		if (res->start <= base && res->end >= base + size - 1) {
  			record_efifb_bar_resource(dev, i, base - res->start);
  			break;
  		}
  	}
  }
  DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_ANY_ID, PCI_ANY_ID, PCI_BASE_CLASS_DISPLAY,
  			       16, efifb_fixup_resources);
  
  #endif
  