video: simplefb

Not really qcom specific, but for now qcom/lk is the one firmware that
is (afaiu) setting up the appropriate dt node for pre-configured
display.  Uses the generic simple-framebuffer DT bindings so this should
be useful on other platforms.

Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/video/Kconfig

@@ -624,4 +624,14 @@ config VIDEO_DW_HDMI
 	  rather requires a SoC-specific glue driver to call it), it
 	  can not be enabled from the configuration menu.
 
+config VIDEO_SIMPLE
+	bool "Simple display driver for preconfigured display"
+	help
+	  Enables a simple generic display driver which utilizes the
+	  simple-framebuffer devicetree bindings.
+
+	  This driver assumes that the display hardware has been initialized
+	  before u-boot starts, and u-boot will simply render to the pre-
+	  allocated frame buffer surface.
+
 endmenu

drivers/video/Makefile

@@ -52,7 +52,7 @@ obj-$(CONFIG_FORMIKE) += formike.o
 obj-$(CONFIG_LG4573) += lg4573.o
 obj-$(CONFIG_AM335X_LCD) += am335x-fb.o
 obj-$(CONFIG_VIDEO_DW_HDMI) += dw_hdmi.o
-
+obj-$(CONFIG_VIDEO_SIMPLE) += simplefb.o
 obj-${CONFIG_VIDEO_TEGRA124} += tegra124/
 obj-${CONFIG_EXYNOS_FB} += exynos/
 obj-${CONFIG_VIDEO_ROCKCHIP} += rockchip/

drivers/video/simplefb.c

+/*
+ * (C) Copyright 2017 Rob Clark
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <fdtdec.h>
+#include <fdt_support.h>
+#include <video.h>
+
+static int simple_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);
+	const void *blob = gd->fdt_blob;
+	const int node = dev_of_offset(dev);
+	const char *format;
+	fdt_addr_t base;
+	fdt_size_t size;
+
+	base = fdtdec_get_addr_size_auto_parent(blob, dev_of_offset(dev->parent),
+			node, "reg", 0, &size, false);
+	if (base == FDT_ADDR_T_NONE) {
+		debug("%s: Failed to decode memory region\n", __func__);
+		return -EINVAL;
+	}
+
+	debug("%s: base=%llx, size=%llu\n", __func__, base, size);
+
+	/*
+	 * TODO is there some way to reserve the framebuffer
+	 * region so it isn't clobbered?
+	 */
+	plat->base = base;
+	plat->size = size;
+
+	video_set_flush_dcache(dev, true);
+
+	debug("%s: Query resolution...\n", __func__);
+
+	uc_priv->xsize = fdtdec_get_uint(blob, node, "width", 0);
+	uc_priv->ysize = fdtdec_get_uint(blob, node, "height", 0);
+	uc_priv->rot = 0;
+
+	format = fdt_getprop(blob, node, "format", NULL);
+	debug("%s: %dx%d@%s\n", __func__, uc_priv->xsize, uc_priv->ysize, format);
+
+	if (strcmp(format, "r5g6b5") == 0) {
+		uc_priv->bpix = VIDEO_BPP16;
+	} else if (strcmp(format, "a8b8g8r8") == 0) {
+		uc_priv->bpix = VIDEO_BPP32;
+	} else {
+		printf("%s: invalid format: %s\n", __func__, format);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct udevice_id simple_video_ids[] = {
+	{ .compatible = "simple-framebuffer" },
+	{ }
+};
+
+U_BOOT_DRIVER(simple_video) = {
+	.name	= "simple_video",
+	.id	= UCLASS_VIDEO,
+	.of_match = simple_video_ids,
+	.probe	= simple_video_probe,
+	.flags	= DM_FLAG_PRE_RELOC,
+};