Add support to configure the active framebuffer for the kernel through
device tree.
Signed-off-by: Andre Heider <a.heider@xxxxxxxxx>
---
drivers/video/Kconfig | 8 +++
drivers/video/Makefile | 1 +
drivers/video/simplefb.c | 171 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 180 insertions(+)
create mode 100644 drivers/video/simplefb.c
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index b532e7d..ccfaba8 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -77,4 +77,12 @@ config DRIVER_VIDEO_BCM2835
help
Add support for the BCM2835/VideoCore frame buffer device.
+config DRIVER_VIDEO_SIMPLEFB
+ bool "Simple framebuffer support"
+ depends on OFTREE
+ depends on DRIVER_VIDEO_BCM2835
+ help
+ Add support for setting up the kernel's simple framebuffer driver
+ based on the active barebox framebuffer.
+
endif
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index 244feab..31edfca 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -10,3 +10,4 @@ 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_BCM2835) += bcm2835.o
+obj-$(CONFIG_DRIVER_VIDEO_SIMPLEFB) += simplefb.o
diff --git a/drivers/video/simplefb.c b/drivers/video/simplefb.c
new file mode 100644
index 0000000..3ea4ad4
--- /dev/null
+++ b/drivers/video/simplefb.c
@@ -0,0 +1,171 @@
+/*
+ * SimpleFB driver
+ *
+ * Copyright (C) 2013 Andre Heider
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#define pr_fmt(fmt) "simplefb: " fmt
+
+#include <common.h>
+#include <errno.h>
+#include <fb.h>
+#include <fcntl.h>
+#include <fs.h>
+#include <init.h>
+#include <xfuncs.h>
+
+struct simplefb_mode {
+ const char *format;
+ u32 bpp;
+ struct fb_bitfield red;
+ struct fb_bitfield green;
+ struct fb_bitfield blue;
+ struct fb_bitfield transp;
+};
+
+/*
+ * These values have to match the kernel's simplefb driver.
+ * See Documentation/devicetree/bindings/video/simple-framebuffer.txt
+ */
+static const struct simplefb_mode simplefb_modes[] = {
+ {
+ .format = "r5g6b5",
+ .bpp = 16,
+ .red = { .length = 5, .offset = 11 },
+ .green = { .length = 6, .offset = 5 },
+ .blue = { .length = 5, .offset = 0 },
+ .transp = { .length = 0, .offset = 0 },
+ },
+};
+
+static bool simplefb_bitfield_cmp(const struct fb_bitfield *a,
+ const struct fb_bitfield *b)
+{
+ if (a->offset != b->offset)
+ return false;
+ if (a->length != b->length)
+ return false;
+ if (a->msb_right != b->msb_right)
+ return false;
+
+ return true;
+}
+
+static const struct simplefb_mode *simplefb_find_mode(const struct fb_info *fbi)
+{
+ const struct simplefb_mode *mode;
+ u32 i;
+
+ for (i = 0; i < ARRAY_SIZE(simplefb_modes); ++i) {
+ mode = &simplefb_modes[i];
+
+ if (fbi->bits_per_pixel != mode->bpp)
+ continue;
+ if (!simplefb_bitfield_cmp(&fbi->red, &mode->red))
+ continue;
+ if (!simplefb_bitfield_cmp(&fbi->green, &mode->green))
+ continue;
+ if (!simplefb_bitfield_cmp(&fbi->blue, &mode->blue))
+ continue;
+ if (!simplefb_bitfield_cmp(&fbi->transp, &mode->transp))
+ continue;
+
+ return mode;
+ }
+
+ return NULL;
+}
+
+static int simplefb_create_node(struct device_node *root,
+ const struct fb_info *fbi, const char *format)
+{
+ const char *compat = "simple-framebuffer";
+ const char *disabled = "disabled";
+ const char *okay = "okay";
+ struct device_node *node;
+ u32 cells[2];
+ int ret;
+
+ node = of_create_node(root, "/framebuffer");
+ if (!node)
+ return -ENOMEM;
+
+ ret = of_set_property(node, "status", disabled,
+ strlen(disabled) + 1, 1);
+ if (ret < 0)
+ return ret;
+
+ ret = of_set_property(node, "compatible", compat, strlen(compat) + 1, 1);
+ if (ret)
+ return ret;
+
+ cells[0] = cpu_to_be32((u32)fbi->screen_base);
+ cells[1] = cpu_to_be32(fbi->line_length * fbi->yres);
+ ret = of_set_property(node, "reg", cells, sizeof(cells[0]) * 2, 1);
+ if (ret < 0)
+ return ret;
+
+ cells[0] = cpu_to_be32(fbi->xres);
+ ret = of_set_property(node, "width", cells, sizeof(cells[0]), 1);
+ if (ret < 0)
+ return ret;
+
+ cells[0] = cpu_to_be32(fbi->yres);
+ ret = of_set_property(node, "height", cells, sizeof(cells[0]), 1);
+ if (ret < 0)
+ return ret;
+
+ cells[0] = cpu_to_be32(fbi->line_length);
+ ret = of_set_property(node, "stride", cells, sizeof(cells[0]), 1);
+ if (ret < 0)
+ return ret;
+
+ ret = of_set_property(node, "format", format, strlen(format) + 1, 1);
+ if (ret < 0)
+ return ret;
+
+ return of_set_property(node, "status", okay, strlen(okay) + 1, 1);
+}
+
+static int simplefb_of_fixup(struct device_node *root)
+{
+ struct fb_info fbi;
+ const struct simplefb_mode *mode;
+ int fd, ret;
+
+ fd = open("/dev/fb0", O_RDONLY);
+ if (fd < 0) {
+ pr_err("failed to open /dev/fb0: %d\n", fd);
+ return fd;
+ }
+
+ ret = ioctl(fd, FBIOGET_SCREENINFO, &fbi);
+ close(fd);
+
+ if (ret) {
+ pr_err("failed to get the framebuffer info: %d\n", ret);
+ return ret;
+ }
+
+ mode = simplefb_find_mode(&fbi);
+ if (!mode) {
+ pr_err("the framebuffer format is incompatible\n");
+ return -EINVAL;
+ }
+
+ ret = simplefb_create_node(root, &fbi, mode->format);
+ if (ret)
+ pr_err("failed to create node: %d\n", ret);
+ else
+ pr_info("created %s node\n", mode->format);
+
+ return ret;
+}
+
+static int simplefb_init(void) {
+ of_register_fixup(simplefb_of_fixup);
+ return 0;
+}
+late_initcall(simplefb_init);
--
1.8.3.2
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