x86_64 EFI boot support: EFI frame buffer driver

This patch adds Graphics Output Protocol support to the kernel. UEFI2.0 spec
deprecates Universal Graphics Adapter (UGA) protocol and only Graphics Output
Protocol (GOP) is produced. Therefore, the boot loader needs to query the
UEFI firmware with appropriate Output Protocol and pass the video information
to the kernel. As a result of GOP protocol, an EFI framebuffer driver is
needed for displaying console messages. The patch adds a EFI framebuffer
driver. The EFI frame buffer driver in this patch is based on the Intel Mac
framebuffer driver.

The ELILO bootloader takes care of passing the video information as
appropriate for EFI firmware.

The framebuffer driver has been tested in i386 kernel and x86_64 kernel on EFI
platform.

Signed-off-by: Chandramouli Narayanan <[e-mail]>
Signed-off-by: Huang Ying <[e-mail]>
Cc: "H. Peter Anvin" <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Andi Kleen <[e-mail]>
Cc: "Antonino A. Daplas" <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/video/Kconfig

···
 	  You will get a boot time penguin logo at no additional cost. Please
 	  read <file:Documentation/fb/vesafb.txt>. If unsure, say Y.
 
+config FB_EFI
+	bool "EFI-based Framebuffer Support"
+	depends on (FB = y) && X86
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	help
+	  This is the EFI frame buffer device driver. If the firmware on
+	  your platform is UEFI2.0, select Y to add support for
+	  Graphics Output Protocol for early console messages to appear.
+
 config FB_IMAC
 	bool "Intel-based Macintosh Framebuffer Support"
 	depends on (FB = y) && X86 && EFI

drivers/video/Makefile

···
 obj-$(CONFIG_FB_UVESA)            += uvesafb.o
 obj-$(CONFIG_FB_VESA)             += vesafb.o
 obj-$(CONFIG_FB_IMAC)             += imacfb.o
+obj-$(CONFIG_FB_EFI)              += efifb.o
 obj-$(CONFIG_FB_VGA16)            += vga16fb.o
 obj-$(CONFIG_FB_OF)               += offb.o
 obj-$(CONFIG_FB_BF54X_LQ043)	  += bf54x-lq043fb.o

drivers/video/efifb.c

···
+/*
+ * Framebuffer driver for EFI/UEFI based system
+ *
+ * (c) 2006 Edgar Hucek <[e-mail]>
+ * Original efi driver written by Gerd Knorr <[e-mail]>
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/fb.h>
+#include <linux/platform_device.h>
+#include <linux/screen_info.h>
+
+#include <video/vga.h>
+
+static struct fb_var_screeninfo efifb_defined __initdata = {
+	.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 __initdata = {
+	.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   >>= 8;
+		green >>= 8;
+		blue  >>= 8;
+		((u32 *)(info->pseudo_palette))[regno] =
+			(red   << info->var.red.offset)   |
+			(green << info->var.green.offset) |
+			(blue  << info->var.blue.offset);
+	}
+	return 0;
+}
+
+static struct fb_ops efifb_ops = {
+	.owner		= THIS_MODULE,
+	.fb_setcolreg	= efifb_setcolreg,
+	.fb_fillrect	= cfb_fillrect,
+	.fb_copyarea	= cfb_copyarea,
+	.fb_imageblit	= cfb_imageblit,
+};
+
+static int __init efifb_probe(struct platform_device *dev)
+{
+	struct fb_info *info;
+	int err;
+	unsigned int size_vmode;
+	unsigned int size_remap;
+	unsigned int size_total;
+
+	efifb_fix.smem_start = screen_info.lfb_base;
+	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_vmode)
+		size_remap = size_vmode;
+	if (size_remap > size_total)
+		size_remap = size_total;
+	efifb_fix.smem_len = size_remap;
+
+	if (!request_mem_region(efifb_fix.smem_start, size_total, "efifb"))
+		/* We cannot make this fatal. Sometimes this comes from magic
+		   spaces our resource handlers simply don't know about */
+		printk(KERN_WARNING
+		       "efifb: cannot reserve video memory at 0x%lx\n",
+			efifb_fix.smem_start);
+
+	info = framebuffer_alloc(sizeof(u32) * 16, &dev->dev);
+	if (!info) {
+		err = -ENOMEM;
+		goto err_release_mem;
+	}
+	info->pseudo_palette = info->par;
+	info->par = NULL;
+
+	info->screen_base = ioremap(efifb_fix.smem_start, efifb_fix.smem_len);
+	if (!info->screen_base) {
+		printk(KERN_ERR "efifb: abort, cannot ioremap video memory "
+				"0x%x @ 0x%lx\n",
+			efifb_fix.smem_len, efifb_fix.smem_start);
+		err = -EIO;
+		goto err_unmap;
+	}
+
+	printk(KERN_INFO "efifb: framebuffer at 0x%lx, mapped to 0x%p, "
+	       "using %dk, total %dk\n",
+	       efifb_fix.smem_start, info->screen_base,
+	       size_remap/1024, size_total/1024);
+	printk(KERN_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;
+	printk(KERN_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;
+
+	printk(KERN_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;
+
+	if (fb_alloc_cmap(&info->cmap, 256, 0) < 0) {
+		err = -ENOMEM;
+		goto err_unmap;
+	}
+	if (register_framebuffer(info) < 0) {
+		err = -EINVAL;
+		goto err_fb_dealoc;
+	}
+	printk(KERN_INFO "fb%d: %s frame buffer device\n",
+	       info->node, info->fix.id);
+	return 0;
+
+err_fb_dealoc:
+	fb_dealloc_cmap(&info->cmap);
+err_unmap:
+	iounmap(info->screen_base);
+	framebuffer_release(info);
+err_release_mem:
+	release_mem_region(efifb_fix.smem_start, size_total);
+	return err;
+}
+
+static struct platform_driver efifb_driver = {
+	.probe	= efifb_probe,
+	.driver	= {
+		.name	= "efifb",
+	},
+};
+
+static struct platform_device efifb_device = {
+	.name	= "efifb",
+};
+
+static int __init efifb_init(void)
+{
+	int ret;
+
+	if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
+		return -ENODEV;
+
+	ret = platform_driver_register(&efifb_driver);
+
+	if (!ret) {
+		ret = platform_device_register(&efifb_device);
+		if (ret)
+			platform_driver_unregister(&efifb_driver);
+	}
+	return ret;
+}
+module_init(efifb_init);
+
+MODULE_LICENSE("GPL");

include/linux/screen_info.h

···
 
 #define VIDEO_TYPE_PMAC		0x60	/* PowerMacintosh frame buffer. */
 
+#define VIDEO_TYPE_EFI		0x70	/* EFI graphic mode		*/
+
 #ifdef __KERNEL__
 extern struct screen_info screen_info;