[U-Boot] [PATCH 15/18] dm: video: Add an EFI framebuffer driver

[Bin Meng]

This adds a DM video driver for U-Boot as the EFI payload. The driver
makes use of all necessary information from the passed EFI GOP info
to create a linear framebuffer device, as if it were initialized by
U-Boot itself.

Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
---

 drivers/video/Kconfig  |   9 +++
 drivers/video/Makefile |   1 +
 drivers/video/efi.c    | 146 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 156 insertions(+)
 create mode 100644 drivers/video/efi.c

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 4c4d286..5ee9032 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -156,6 +156,15 @@ config VIDEO_COREBOOT
 	  coreboot already. This can in principle be used with any platform
 	  that coreboot supports.
 
+config VIDEO_EFI
+	bool "Enable EFI framebuffer driver support"
+	depends on EFI_STUB
+	help
+	  Turn on this option to enable a framebuffeer driver when U-Boot is
+	  loaded as a payload (see README.u-boot_on_efi) by an EFI BIOS where
+	  the graphics device is configured by the EFI BIOS already. This can
+	  in principle be used with any platform that has an EFI BIOS.
+
 config VIDEO_VESA
 	bool "Enable VESA video driver support"
 	default n
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index cf7ad28..7c89c67 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -32,6 +32,7 @@ obj-$(CONFIG_LD9040) += ld9040.o
 obj-$(CONFIG_VIDEO_BCM2835) += bcm2835.o
 obj-$(CONFIG_VIDEO_COREBOOT) += coreboot.o
 obj-$(CONFIG_VIDEO_DA8XX) += da8xx-fb.o videomodes.o
+obj-$(CONFIG_VIDEO_EFI) += efi.o
 obj-$(CONFIG_VIDEO_LCD_ANX9804) += anx9804.o
 obj-$(CONFIG_VIDEO_LCD_HITACHI_TX18D42VM) += hitachi_tx18d42vm_lcd.o
 obj-$(CONFIG_VIDEO_LCD_SSD2828) += ssd2828.o
diff --git a/drivers/video/efi.c b/drivers/video/efi.c
new file mode 100644
index 0000000..653cb47
--- /dev/null
+++ b/drivers/video/efi.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Bin Meng <bmeng.cn at gmail.com>
+ *
+ * EFI framebuffer driver based on GOP
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <efi_api.h>
+#include <vbe.h>
+#include <video.h>
+
+struct pixel {
+	u8 pos;
+	u8 size;
+};
+
+static const struct efi_framebuffer {
+	struct pixel red;
+	struct pixel green;
+	struct pixel blue;
+	struct pixel rsvd;
+} efi_framebuffer_format_map[] = {
+	[EFI_GOT_RGBA8] = { {0, 8}, {8, 8}, {16, 8}, {24, 8} },
+	[EFI_GOT_BGRA8] = { {16, 8}, {8, 8}, {0, 8}, {24, 8} },
+};
+
+static void efi_find_pixel_bits(u32 mask, u8 *pos, u8 *size)
+{
+	u8 first, len;
+
+	first = 0;
+	len = 0;
+
+	if (mask) {
+		while (!(mask & 0x1)) {
+			mask = mask >> 1;
+			first++;
+		}
+
+		while (mask & 0x1) {
+			mask = mask >> 1;
+			len++;
+		}
+	}
+
+	*pos = first;
+	*size = len;
+}
+
+static int save_vesa_mode(struct vesa_mode_info *vesa)
+{
+	struct efi_entry_gopmode *mode;
+	const struct efi_framebuffer *fbinfo;
+	int size;
+	int ret;
+
+	ret = efi_info_get(EFIET_GOP_MODE, (void **)&mode, &size);
+	if (ret == -ENOENT) {
+		debug("efi graphics output protocol mode not found\n");
+		return -ENXIO;
+	}
+
+	vesa->phys_base_ptr = mode->fb_base;
+	vesa->x_resolution = mode->info->width;
+	vesa->y_resolution = mode->info->height;
+
+	if (mode->info->pixel_format < EFI_GOT_BITMASK) {
+		fbinfo = &efi_framebuffer_format_map[mode->info->pixel_format];
+		vesa->red_mask_size = fbinfo->red.size;
+		vesa->red_mask_pos = fbinfo->red.pos;
+		vesa->green_mask_size = fbinfo->green.size;
+		vesa->green_mask_pos = fbinfo->green.pos;
+		vesa->blue_mask_size = fbinfo->blue.size;
+		vesa->blue_mask_pos = fbinfo->blue.pos;
+		vesa->reserved_mask_size = fbinfo->rsvd.size;
+		vesa->reserved_mask_pos = fbinfo->rsvd.pos;
+
+		vesa->bits_per_pixel = 32;
+		vesa->bytes_per_scanline = mode->info->pixels_per_scanline * 4;
+	} else if (mode->info->pixel_format == EFI_GOT_BITMASK) {
+		efi_find_pixel_bits(mode->info->pixel_bitmask[0],
+				    &vesa->red_mask_pos,
+				    &vesa->red_mask_size);
+		efi_find_pixel_bits(mode->info->pixel_bitmask[1],
+				    &vesa->green_mask_pos,
+				    &vesa->green_mask_size);
+		efi_find_pixel_bits(mode->info->pixel_bitmask[2],
+				    &vesa->blue_mask_pos,
+				    &vesa->blue_mask_size);
+		efi_find_pixel_bits(mode->info->pixel_bitmask[3],
+				    &vesa->reserved_mask_pos,
+				    &vesa->reserved_mask_size);
+		vesa->bits_per_pixel = vesa->red_mask_size +
+				       vesa->green_mask_size +
+				       vesa->blue_mask_size +
+				       vesa->reserved_mask_size;
+		vesa->bytes_per_scanline = (mode->info->pixels_per_scanline *
+					    vesa->bits_per_pixel) / 8;
+	} else {
+		debug("efi set unknown framebuffer format: %d\n",
+		      mode->info->pixel_format);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int efi_video_probe(struct udevice *dev)
+{
+	struct video_uc_platdata *plat = dev_get_uclass_platdata(dev);
+	struct video_priv *uc_priv = dev_get_uclass_priv(dev);
+	struct vesa_mode_info *vesa = &mode_info.vesa;
+	int ret;
+
+	/* Initialize vesa_mode_info structure */
+	ret = save_vesa_mode(vesa);
+	if (ret)
+		goto err;
+
+	ret = vbe_setup_video_priv(vesa, uc_priv, plat);
+	if (ret)
+		goto err;
+
+	printf("Video: %dx%dx%d\n", uc_priv->xsize, uc_priv->ysize,
+	       vesa->bits_per_pixel);
+
+	return 0;
+
+err:
+	printf("No video mode configured in EFI!\n");
+	return ret;
+}
+
+static const struct udevice_id efi_video_ids[] = {
+	{ .compatible = "efi-fb" },
+	{ }
+};
+
+U_BOOT_DRIVER(efi_video) = {
+	.name	= "efi_video",
+	.id	= UCLASS_VIDEO,
+	.of_match = efi_video_ids,
+	.probe	= efi_video_probe,
+};
-- 
2.7.4