video: add simplefb driver

barebox has support to fix up a framebuffer it has set up as simplefb
into the device tree of a kernel it boots. Add the counterpart to this,
so barebox itself can reuse an already set up frame buffer.

This is done to support the framebuffer device on the tinyemu RISC-V
machine.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

4 files changed, 158 insertions, 2 deletions

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index b6d468c63c..95d993dde8 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -101,8 +101,14 @@ source "drivers/video/imx-ipu-v3/Kconfig"
 
 source "drivers/video/bochs/Kconfig"
 
+config DRIVER_VIDEO_SIMPLEFB_CLIENT
+	bool "Simple framebuffer client support"
+	depends on OFTREE
+	help
+	  Add support for reusing a previously set up simple framebuffer.
+
 config DRIVER_VIDEO_SIMPLEFB
-	bool "Simple framebuffer support"
+	bool "Simple framebuffer fixup support"
 	depends on OFTREE
 	help
 	  Add support for setting up the kernel's simple framebuffer driver
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index 28d0fe205b..2c002f7e53 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -19,7 +19,8 @@ obj-$(CONFIG_DRIVER_VIDEO_PXA) += pxa.o
 obj-$(CONFIG_DRIVER_VIDEO_SDL) += sdl.o
 obj-$(CONFIG_DRIVER_VIDEO_OMAP) += omap.o
 obj-$(CONFIG_DRIVER_VIDEO_BCM283X) += bcm2835.o
-obj-$(CONFIG_DRIVER_VIDEO_SIMPLEFB) += simplefb.o
+obj-$(CONFIG_DRIVER_VIDEO_SIMPLEFB_CLIENT) += simplefb-client.o
+obj-$(CONFIG_DRIVER_VIDEO_SIMPLEFB) += simplefb-fixup.o
 obj-$(CONFIG_DRIVER_VIDEO_IMX_IPUV3) += imx-ipu-v3/
 obj-$(CONFIG_DRIVER_VIDEO_EFI_GOP) += efi_gop.o
 obj-$(CONFIG_DRIVER_VIDEO_FB_SSD1307) += ssd1307fb.o
diff --git a/drivers/video/simplefb-client.c b/drivers/video/simplefb-client.c
new file mode 100644
index 0000000000..2d0495f616
--- /dev/null
+++ b/drivers/video/simplefb-client.c
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Simplest possible simple frame-buffer driver, as a platform device
+ *
+ * Copyright (c) 2013, Stephen Warren
+ *
+ * Based on q40fb.c, which was:
+ * Copyright (C) 2001 Richard Zidlicky <rz@linux-m68k.org>
+ *
+ * Also based on offb.c, which was:
+ * Copyright (C) 1997 Geert Uytterhoeven
+ * Copyright (C) 1996 Paul Mackerras
+ */
+
+#include <common.h>
+#include <fb.h>
+#include <io.h>
+#include <linux/platform_data/simplefb.h>
+#include <driver.h>
+#include <of.h>
+
+static struct fb_ops simplefb_ops;
+
+static struct simplefb_format simplefb_formats[] = SIMPLEFB_FORMATS;
+
+struct simplefb_params {
+	u32 width;
+	u32 height;
+	u32 stride;
+	struct simplefb_format *format;
+};
+
+static int simplefb_parse_dt(struct device_d *dev,
+			   struct simplefb_params *params)
+{
+	struct device_node *np = dev->device_node;
+	int ret;
+	const char *format;
+	int i;
+
+	ret = of_property_read_u32(np, "width", &params->width);
+	if (ret) {
+		dev_err(dev, "Can't parse width property\n");
+		return ret;
+	}
+
+	ret = of_property_read_u32(np, "height", &params->height);
+	if (ret) {
+		dev_err(dev, "Can't parse height property\n");
+		return ret;
+	}
+
+	ret = of_property_read_u32(np, "stride", &params->stride);
+	if (ret) {
+		dev_err(dev, "Can't parse stride property\n");
+		return ret;
+	}
+
+	ret = of_property_read_string(np, "format", &format);
+	if (ret) {
+		dev_err(dev, "Can't parse format property\n");
+		return ret;
+	}
+	params->format = NULL;
+	for (i = 0; i < ARRAY_SIZE(simplefb_formats); i++) {
+		if (strcmp(format, simplefb_formats[i].name))
+			continue;
+		params->format = &simplefb_formats[i];
+		break;
+	}
+	if (!params->format) {
+		dev_err(dev, "Invalid format value\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int simplefb_probe(struct device_d *dev)
+{
+	int ret;
+	struct simplefb_params params;
+	struct fb_info *info;
+	struct resource *mem;
+
+	ret = -ENODEV;
+	if (dev->device_node)
+		ret = simplefb_parse_dt(dev, &params);
+
+	if (ret)
+		return ret;
+
+	mem = dev_request_mem_resource(dev, 0);
+	if (IS_ERR(mem)) {
+		dev_err(dev, "No memory resource\n");
+		return PTR_ERR(mem);
+	}
+
+	info = xzalloc(sizeof(*info));
+	dev->priv = info;
+
+	info->xres = params.width;
+	info->yres = params.height;
+	info->bits_per_pixel = params.format->bits_per_pixel;
+	info->red = params.format->red;
+	info->green = params.format->green;
+	info->blue = params.format->blue;
+	info->transp = params.format->transp;
+	info->line_length = params.stride;
+
+	info->screen_base = (void *)mem->start;
+	info->screen_size = resource_size(mem);
+
+
+	info->fbops = &simplefb_ops;
+
+	dev_info(dev, "framebuffer at 0x%p, 0x%lx bytes\n",
+		 info->screen_base, info->screen_size);
+	dev_info(dev, "format=%s, mode=%dx%dx%d, linelength=%d\n",
+		 params.format->name,
+		 info->xres, info->yres,
+		 info->bits_per_pixel, info->line_length);
+
+	ret = register_framebuffer(info);
+	if (ret < 0) {
+		dev_err(dev, "Unable to register simplefb: %d\n", ret);
+		return ret;
+	}
+
+	dev_info(dev, "simplefb registered!\n");
+
+	return 0;
+}
+
+static const struct of_device_id simplefb_of_match[] = {
+	{ .compatible = "simple-framebuffer", },
+	{ },
+};
+
+static struct driver_d simplefb_driver = {
+	.name = "simple-framebuffer",
+	.of_compatible = simplefb_of_match,
+	.probe = simplefb_probe,
+};
+device_platform_driver(simplefb_driver);
+
+MODULE_AUTHOR("Stephen Warren <swarren@wwwdotorg.org>");
+MODULE_DESCRIPTION("Simple framebuffer driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/video/simplefb.c b/drivers/video/simplefb-fixup.c
index a2c59de364..a2c59de364 100644
--- a/drivers/video/simplefb.c
+++ b/drivers/video/simplefb-fixup.c