[PATCH v2 0/6] BCM2835 / simple framebuffer support
Sascha Hauer
s.hauer at pengutronix.de
Wed Nov 6 04:46:28 EST 2013
Hi Andre,
On Tue, Nov 05, 2013 at 12:00:58AM +0100, Andre Heider wrote:
> This is v2 of my patch set posted on 10/24.
> It adds framebuffer support for the RPi and provides an additional config
> knob to set up the kernel's simplefb driver. The active barebox framebuffer
> is basis for that feature, so that other platforms can make use of it.
>
> This simplefb option depends on the bcm2835 fb driver since drivers need
> to be aware of simplefb: framebuffers need to stay configured and cannot be
> teared down.
>
> The RPi case is rather simple in this regard. The allocated framebuffer lies
> within the memory range of the VideoCore of the ARM/VC memory split. Hence,
> there is no memory range that needs to be reserved as far as the ARM side
> of things is concerned.
> This likely needs to be added once other fb driver want to use simplefb.
>
> Changes since v1:
> * renamed "pitch" to "line_length" to match the kernel
> * the bcm2835 framebuffer driver is now standalone
> * configuring simplefb for the kernel is based on the active barebox
> framebuffer
I applied this series without the simplefb patch.
For the simplefb I'd like to use the following patch instead. It's your
patch with some adjustments:
- add a register_simplefb device parameter to make it configurable
whether a simplefb node should be created or not.
- register the OF fixup in register_framebuffer(). This way we always
have a simplefb node once a framebuffer is registered without getting
spurious warnings when there is no framebuffer present.
- check if the framebuffer is actually enabled. If it's not, we
shouldn't register a simplefb node.
Are you fine with this and if yes, could you give the patch a test?
It depends on the add-context-pointer-to-of_register_fixup patch I just
posted. Just try the current -next branch, it should contain all you
need for testing.
One oddity I just realized is that my patch will try and create a
/framebuffer node multiple times if multiple framebuffers exist.
I would have to fix this.
Sascha
8<----------------------------------------------------------
>From 97607e85cdc44824e9617c74325bc9bc6405c383 Mon Sep 17 00:00:00 2001
From: Andre Heider <a.heider at gmail.com>
Date: Tue, 5 Nov 2013 00:01:04 +0100
Subject: [PATCH] video: set up the kernel's simple framebuffer driver
Add support to configure the active framebuffer for the kernel through
device tree.
Signed-off-by: Andre Heider <a.heider at gmail.com>
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
drivers/video/Kconfig | 7 ++
drivers/video/Makefile | 1 +
drivers/video/fb.c | 7 ++
drivers/video/simplefb.c | 167 +++++++++++++++++++++++++++++++++++++++++++++++
include/fb.h | 7 ++
5 files changed, 189 insertions(+)
create mode 100644 drivers/video/simplefb.c
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index b532e7d..5539266 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -77,4 +77,11 @@ 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
+ 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/fb.c b/drivers/video/fb.c
index 0159994..4263027 100644
--- a/drivers/video/fb.c
+++ b/drivers/video/fb.c
@@ -163,6 +163,13 @@ int register_framebuffer(struct fb_info *info)
if (ret)
goto err_unregister;
+ if (IS_ENABLED(CONFIG_DRIVER_VIDEO_SIMPLEFB)) {
+ ret = fb_register_simplefb(info);
+ if (ret)
+ dev_err(&info->dev, "failed to register simplefb: %s\n",
+ strerror(-ret));
+ }
+
return 0;
err_unregister:
diff --git a/drivers/video/simplefb.c b/drivers/video/simplefb.c
new file mode 100644
index 0000000..834704b
--- /dev/null
+++ b/drivers/video/simplefb.c
@@ -0,0 +1,167 @@
+/*
+ * 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, void *ctx)
+{
+ struct fb_info *info = ctx;
+ const struct simplefb_mode *mode;
+ int ret;
+
+ /* only create node if we are requested to */
+ if (!info->register_simplefb)
+ return 0;
+
+ /* do not create node for disabled framebuffers */
+ if (!info->enabled)
+ return 0;
+
+ mode = simplefb_find_mode(info);
+ if (!mode) {
+ dev_err(&info->dev, "fb format is incompatible with simplefb\n");
+ return -EINVAL;
+ }
+
+ ret = simplefb_create_node(root, info, mode->format);
+ if (ret)
+ dev_err(&info->dev, "failed to create node: %d\n", ret);
+ else
+ dev_info(&info->dev, "created %s node\n", mode->format);
+
+ return ret;
+}
+
+int fb_register_simplefb(struct fb_info *info)
+{
+ dev_add_param_bool(&info->dev, "register_simplefb",
+ NULL, NULL, &info->register_simplefb, NULL);
+
+ return of_register_fixup(simplefb_of_fixup, info);
+}
diff --git a/include/fb.h b/include/fb.h
index cf9ffa0..98d5a03 100644
--- a/include/fb.h
+++ b/include/fb.h
@@ -105,6 +105,9 @@ struct fb_info {
int enabled;
int p_enable;
+ int register_simplefb; /* If true a simplefb device node will
+ * be created.
+ */
};
int register_framebuffer(struct fb_info *info);
@@ -115,5 +118,9 @@ int register_framebuffer(struct fb_info *info);
extern struct bus_type fb_bus;
+/* fb internal functions */
+
+int fb_register_simplefb(struct fb_info *info);
+
#endif /* __FB_H */
--
1.8.4.rc3
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