[RFC PATCH 0/6] Boot logo supplied by the device tree

[RFC PATCH 0/6] Boot logo supplied by the device tree

[Max Pedraza]

Embedded products routinely need their own boot logo. Today the only way to
get one is to replace one of the logo_*_clut224.ppm files in the kernel
source tree, which bakes the image into the kernel image. Two products that
share a board support package but differ in branding therefore need two
kernel builds, and rebranding an existing product means rebuilding and
requalifying a kernel for what is purely a cosmetic change.

This series lets the logo be described by the device tree instead: a node
compatible with "linux,boot-logo-clut224" supplies the image in the same
paletted format the built-in CLUT224 logos already use, and the kernel
prefers it over the built-in ones when it is present and enabled. If the
node is absent or disabled, nothing changes.

The image can come from the node itself (patches 1-2) or from a reserved
memory region the bootloader filled in (patches 4-5), because the image and
its placement are independent axes of variation. One board sold to several
customers wants several device trees differing in the logo. One customer
with several products built on that board, with different panels, wants the
same logo placed differently on each: there the image belongs in a shared
binary and only the placement belongs in the device tree. Patch 3 adds that
placement.

We have been carrying a cruder version of this downstream on an AM335x
product since 2020, across a handful of board revisions, and it has removed
a real maintenance burden for us. This is an attempt to find out whether
something along these lines is wanted upstream, and if so in what shape --
hence RFC.

I am aware of the contentious part: a bitmap is not hardware, and the device
tree is not an obvious place to put one. The argument for it is that the
logo identifies the board in the same way the model property does, it is
available before any filesystem is mounted, and it is per board rather than
per kernel. The argument against is presumably that this is policy and
belongs in userspace or in the bootloader. I would rather hear that
explicitly than keep the patch downstream on a guess, and if the concept is
rejected I would still like to know whether a smaller subset -- say the
placement properties driven from the fbcon command line, without any image
in the device tree -- would be worth submitting separately.

Patches 4 and 5 are separable; the series is useful without them if the
reserved memory path is thought to be one mechanism too many.

Not included, though it exists in our downstream version: a hook in
drm_fb_helper so the logo is drawn when CONFIG_FRAMEBUFFER_CONSOLE is
disabled, which is the common case for a product that only wants a splash
screen. Today fb_show_logo() is reached from fbcon alone. That is a DRM
question rather than an fbdev one and deserves a separate posting.

Notes on the binding:

  - The palette size is derived from the length of the "clut" property
    instead of being a separate property, so it cannot disagree with the
    palette actually supplied.
  - "data" holds plain palette indices. The 32 entry offset the frame
    buffer layer reserves for the console is an implementation detail and
    is applied by the kernel.
  - "logo-position" and "logo-offset" are spelled with the prefix because
    plain "position" and "offset" are already used elsewhere in the tree
    with an incompatible type, which dtschema rejects.
  - "logo-centered" overlaps with the existing fb_center_logo, but it is
    per device tree rather than per fbcon command line, and it composes
    with "logo-offset". That combination is what panels with a partially
    visible area need, where the usable region is not the centre of the
    mode; the hardware this came from is an 800x480 panel of which only the
    bottom 320 rows are visible.
  - The reserved memory path takes a "memory-region" phandle rather than a
    bare address. The reservation is what makes the memory safe to read at
    all, and it is what gives the kernel a size to bounds check against.

The byte arrays are not written by hand: patch 6 adds ppmtodtlogo, a host
tool along the lines of the existing pnmtologo -- plain C, no dependencies,
no quantization of its own -- that turns a PPM image into the node or into
the memory region blob. It is what produced everything tested below.

Testing: build tested for arm with CONFIG_LOGO_DT_CLUT224 both enabled and
disabled, W=1 clean, checkpatch --strict clean, dt_binding_check clean. The
schema was also checked against deliberately malformed nodes, including
supplying both image sources at once and neither.

Boot tested under qemu-system-arm -M versatilepb with PL111 and fbcon, at
16bpp. A 160x120 logo placed with "logo-centered" plus a "logo-offset" of
<0 120> lands at exactly the expected coordinates, and every pixel matches
the source image once the source is truncated to RGB565, with identical
per-colour pixel counts. Supplying the same image through a reserved region
loaded at boot produces a bit for bit identical screen. Blobs with a bad
magic, a geometry larger than the reservation, an out of range pixel and an
oversized palette are each rejected with a warning and fall back to the
built-in logo, with no crash.

That boot test earned its keep: the first version of patch 3 drew the logo
correctly and then had it erased, because fb_prepare_logo() still reserved
only the logo's own height while the logo itself had been moved further
down. Nothing in the build or the static checks catches that.

Also boot tested on real hardware: an AM335x board (tilcdc) with an 800x480
panel, migrated from the 4.19 product kernel this derives from. Both image
sources show the product logo where expected -- embedded in the device tree,
and in a bootloader-loaded reserved memory region at the same address the
4.19 system already used. That system builds without
CONFIG_FRAMEBUFFER_CONSOLE, so the drawing there goes through the separate
drm_fb_helper hook mentioned above as not included; the parsing, validation
and placement exercised are those of this series.

Max Pedraza (6):
  dt-bindings: display: add a device tree supplied boot logo
  video: logo: allow the boot logo to come from the device tree
  fbdev: honour the device tree boot logo placement properties
  dt-bindings: display: allow the boot logo in a reserved memory region
  video: logo: allow the boot logo to come from a reserved memory region
  video: logo: add ppmtodtlogo host tool

 .../display/linux,boot-logo-clut224.yaml      | 152 +++++++
 MAINTAINERS                                   |   1 +
 drivers/video/fbdev/core/fb_logo.c            | 174 ++++++++
 drivers/video/logo/Kconfig                    |  13 +
 drivers/video/logo/Makefile                   |   6 +-
 drivers/video/logo/logo.c                     | 256 +++++++++++
 drivers/video/logo/ppmtodtlogo.c              | 402 ++++++++++++++++++
 7 files changed, 1003 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/display/linux,boot-logo-clut224.yaml
 create mode 100644 drivers/video/logo/ppmtodtlogo.c

-- 
2.39.5

[RFC PATCH 1/6] dt-bindings: display: add a device tree supplied boot logo

[Max Pedraza]

Embedded products frequently need a product specific boot logo. Today the
only way to get one is to replace one of the logo_*_clut224.ppm files in
the kernel source tree, which bakes the image into the kernel image: a
change of branding, or a second product sharing the same board support,
requires a separate kernel build.

Add a binding for a "linux,boot-logo-clut224" node, which carries the logo
in the same paletted format the built-in CLUT224 logos already use, plus a
few optional properties describing where on the screen it is drawn.

The palette size is derived from the length of the "clut" property rather
than spelled out separately, and "data" holds plain palette indices; the
32 entry offset the frame buffer layer reserves for the console is an
implementation detail and is applied by the kernel, not by the binding.

Signed-off-by: Max Pedraza <maximpedraza@gmail.com>
---
 .../display/linux,boot-logo-clut224.yaml      | 108 ++++++++++++++++++
 MAINTAINERS                                   |   1 +
 2 files changed, 109 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/linux,boot-logo-clut224.yaml

diff --git a/Documentation/devicetree/bindings/display/linux,boot-logo-clut224.yaml b/Documentation/devicetree/bindings/display/linux,boot-logo-clut224.yaml
new file mode 100644
index 000000000..10845378d
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/linux,boot-logo-clut224.yaml
@@ -0,0 +1,108 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/linux,boot-logo-clut224.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Boot logo supplied by the device tree
+
+maintainers:
+  - Max Pedraza <maximpedraza@gmail.com>
+
+description: |
+  Embedded systems commonly need a product specific boot logo. Today the only
+  way to get one is to replace one of the logo_*_clut224.ppm files in the
+  kernel source tree, which means the image is baked into the kernel image and
+  a new kernel has to be built and deployed to change it.
+
+  This node lets the boot logo be described by the device tree instead, so that
+  a single kernel image can serve several products, or several revisions of the
+  same product, that only differ in branding.
+
+  The image is stored in the same paletted format the in-kernel CLUT224 logos
+  use: a palette of at most 224 RGB entries plus one palette index per pixel.
+
+properties:
+  compatible:
+    const: linux,boot-logo-clut224
+
+  width:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Logo width in pixels.
+    minimum: 1
+    maximum: 65535
+
+  height:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Logo height in pixels.
+    minimum: 1
+    maximum: 65535
+
+  clut:
+    $ref: /schemas/types.yaml#/definitions/uint8-array
+    description:
+      Colour lookup table, as consecutive red, green and blue bytes per entry.
+      The number of entries is derived from the property length and must not
+      exceed 224.
+    minItems: 3
+    maxItems: 672
+
+  data:
+    $ref: /schemas/types.yaml#/definitions/uint8-array
+    description:
+      One byte per pixel, left to right and top to bottom, each byte being an
+      index into the colour lookup table. The property length must be equal to
+      width multiplied by height.
+
+  logo-position:
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    description:
+      X and Y coordinates, in pixels, of the top left corner of the logo.
+      Defaults to the top left corner of the screen.
+    items:
+      - description: X coordinate
+      - description: Y coordinate
+
+  logo-offset:
+    $ref: /schemas/types.yaml#/definitions/int32-array
+    description:
+      X and Y displacement, in pixels, applied after the logo has been placed.
+      Mostly useful together with logo-centered.
+    items:
+      - description: X displacement
+      - description: Y displacement
+
+  logo-centered:
+    type: boolean
+    description:
+      Centre the logo on the screen, overriding logo-position.
+
+  logo-rotation:
+    $ref: /schemas/types.yaml#/definitions/string
+    description: Rotation applied to the logo before it is drawn.
+    enum: [none, cw, ccw, ud]
+    default: none
+
+required:
+  - compatible
+  - width
+  - height
+  - clut
+  - data
+
+additionalProperties: false
+
+examples:
+  - |
+    // A 4x2 logo using three colours, centred on the screen.
+    logo {
+        compatible = "linux,boot-logo-clut224";
+        width = <4>;
+        height = <2>;
+        clut = /bits/ 8 <0xff 0x00 0x00
+                         0x00 0xff 0x00
+                         0x00 0x00 0xff>;
+        data = /bits/ 8 <0x00 0x01 0x01 0x00
+                         0x02 0x00 0x00 0x02>;
+        logo-centered;
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index e08767323..3f0ede165 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9951,6 +9951,7 @@ L:	dri-devel@lists.freedesktop.org
 S:	Maintained
 Q:	http://patchwork.kernel.org/project/linux-fbdev/list/
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev.git
+F:	Documentation/devicetree/bindings/display/linux,boot-logo-clut224.yaml
 F:	Documentation/fb/
 F:	drivers/video/
 F:	include/linux/fb.h
-- 
2.39.5

[RFC PATCH 2/6] video: logo: allow the boot logo to come from the device tree

[Max Pedraza]

With CONFIG_LOGO_DT_CLUT224 enabled, look for a node compatible with
"linux,boot-logo-clut224" and, when one is present and enabled, use the
image it carries in preference to the logos built into the kernel image.

This lets a single kernel image serve several products, or several
revisions of one product, that differ only in branding, at the cost of a
larger device tree blob.

The image is validated while it is parsed: the palette must be at most 224
entries, the pixel data length must match the declared geometry, and every
pixel must reference an existing palette entry. A malformed node is
reported and ignored, falling back to the built-in logo.

The two allocations live for as long as the built-in logos do; they are
released from fb_logo_late_init(), next to where the __initdata logos are
marked as freed.

If the node is absent or disabled, behaviour is unchanged.

Signed-off-by: Max Pedraza <maximpedraza@gmail.com>
---
 drivers/video/logo/Kconfig |  13 +++
 drivers/video/logo/logo.c  | 157 +++++++++++++++++++++++++++++++++++++
 2 files changed, 170 insertions(+)

diff --git a/drivers/video/logo/Kconfig b/drivers/video/logo/Kconfig
index ce6bb7535..4af349b20 100644
--- a/drivers/video/logo/Kconfig
+++ b/drivers/video/logo/Kconfig
@@ -70,4 +70,17 @@ config LOGO_SUPERH_CLUT224
 	depends on SUPERH
 	default y
 
+config LOGO_DT_CLUT224
+	bool "224-color logo supplied by the device tree"
+	depends on OF
+	help
+	  Look for a boot logo in the device tree, in a node compatible with
+	  "linux,boot-logo-clut224", instead of using one of the logos built
+	  into the kernel image. This allows a single kernel image to be used
+	  by several products that only differ in branding, at the cost of
+	  making the device tree blob larger.
+
+	  If no such node is present, or it is disabled, the built-in logo
+	  selected above is used, so saying Y here is safe. If unsure, say N.
+
 endif # LOGO
diff --git a/drivers/video/logo/logo.c b/drivers/video/logo/logo.c
index 141f15a9a..b4f533df0 100644
--- a/drivers/video/logo/logo.c
+++ b/drivers/video/logo/logo.c
@@ -11,6 +11,9 @@
  */
 
 #include <linux/linux_logo.h>
+#include <linux/of.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
 #include <linux/stddef.h>
 #include <linux/module.h>
 
@@ -22,6 +25,155 @@ static bool nologo;
 module_param(nologo, bool, 0);
 MODULE_PARM_DESC(nologo, "Disables startup logo");
 
+#ifdef CONFIG_LOGO_DT_CLUT224
+
+#define LOGO_DT_COMPATIBLE	"linux,boot-logo-clut224"
+#define LOGO_DT_MAX_CLUT	224
+/*
+ * The first 32 palette entries are reserved for the console, so the logo
+ * colours start at index 32. That is an implementation detail of the frame
+ * buffer layer rather than a property of the image, so the device tree stores
+ * plain indices and the offset is applied here.
+ */
+#define LOGO_DT_CLUT_OFFSET	32
+/* Sanity limit on the image size, a device tree is not a good place for more */
+#define LOGO_DT_MAX_PIXELS	SZ_32M
+
+static struct linux_logo logo_dt_clut224 = {
+	.type		= LINUX_LOGO_CLUT224,
+};
+
+static unsigned char *logo_dt_clut;
+static unsigned char *logo_dt_data;
+
+static int logo_dt_parse(struct device_node *np)
+{
+	unsigned int clutsize, npixels, i;
+	unsigned char *clut, *data;
+	u32 width, height;
+	int len, ret;
+
+	ret = of_property_read_u32(np, "width", &width);
+	if (ret)
+		return ret;
+
+	ret = of_property_read_u32(np, "height", &height);
+	if (ret)
+		return ret;
+
+	if (!width || !height || (u64)width * height > LOGO_DT_MAX_PIXELS)
+		return -EINVAL;
+
+	npixels = width * height;
+
+	len = of_property_count_u8_elems(np, "clut");
+	if (len < 3 || len % 3)
+		return -EINVAL;
+
+	clutsize = len / 3;
+	if (clutsize > LOGO_DT_MAX_CLUT)
+		return -EINVAL;
+
+	ret = of_property_count_u8_elems(np, "data");
+	if (ret < 0)
+		return ret;
+	if ((unsigned int)ret != npixels)
+		return -EINVAL;
+
+	clut = kmalloc(len, GFP_KERNEL);
+	if (!clut)
+		return -ENOMEM;
+
+	data = kmalloc(npixels, GFP_KERNEL);
+	if (!data) {
+		ret = -ENOMEM;
+		goto err_free_clut;
+	}
+
+	ret = of_property_read_u8_array(np, "clut", clut, len);
+	if (ret)
+		goto err_free_data;
+
+	ret = of_property_read_u8_array(np, "data", data, npixels);
+	if (ret)
+		goto err_free_data;
+
+	for (i = 0; i < npixels; i++) {
+		if (data[i] >= clutsize) {
+			ret = -ERANGE;
+			goto err_free_data;
+		}
+		data[i] += LOGO_DT_CLUT_OFFSET;
+	}
+
+	logo_dt_clut = clut;
+	logo_dt_data = data;
+
+	logo_dt_clut224.width = width;
+	logo_dt_clut224.height = height;
+	logo_dt_clut224.clutsize = clutsize;
+	logo_dt_clut224.clut = clut;
+	logo_dt_clut224.data = data;
+
+	return 0;
+
+err_free_data:
+	kfree(data);
+err_free_clut:
+	kfree(clut);
+	return ret;
+}
+
+static const struct linux_logo *logo_dt_find(void)
+{
+	static bool probed;
+	struct device_node *np;
+	int ret;
+
+	if (probed)
+		return logo_dt_data ? &logo_dt_clut224 : NULL;
+
+	probed = true;
+
+	np = of_find_compatible_node(NULL, NULL, LOGO_DT_COMPATIBLE);
+	if (!np)
+		return NULL;
+
+	if (of_device_is_available(np)) {
+		ret = logo_dt_parse(np);
+		if (ret)
+			pr_warn("logo: ignoring malformed %pOF node (%d)\n",
+				np, ret);
+	}
+
+	of_node_put(np);
+
+	return logo_dt_data ? &logo_dt_clut224 : NULL;
+}
+
+static void logo_dt_free(void)
+{
+	logo_dt_clut224.clut = NULL;
+	logo_dt_clut224.data = NULL;
+
+	kfree(logo_dt_clut);
+	logo_dt_clut = NULL;
+
+	kfree(logo_dt_data);
+	logo_dt_data = NULL;
+}
+
+#else /* !CONFIG_LOGO_DT_CLUT224 */
+
+static inline const struct linux_logo *logo_dt_find(void)
+{
+	return NULL;
+}
+
+static inline void logo_dt_free(void) { }
+
+#endif /* CONFIG_LOGO_DT_CLUT224 */
+
 /*
  * Logos are located in the initdata, and will be freed in kernel_init.
  * Use late_init to mark the logos as freed to prevent any further use.
@@ -32,6 +184,7 @@ static bool logos_freed;
 static int __init fb_logo_late_init(void)
 {
 	logos_freed = true;
+	logo_dt_free();
 	return 0;
 }
 
@@ -71,6 +224,10 @@ const struct linux_logo * __ref fb_find_logo(int depth)
 	}
 	
 	if (depth >= 8) {
+		/* A logo supplied by the device tree wins over the built-in ones */
+		logo = logo_dt_find();
+		if (logo)
+			return logo;
 #ifdef CONFIG_LOGO_LINUX_CLUT224
 		/* Generic Linux logo */
 		logo = &logo_linux_clut224;
-- 
2.39.5

[RFC PATCH 3/6] fbdev: honour the device tree boot logo placement properties

[Max Pedraza]

A logo supplied by the device tree describes a specific product, so where
it lands on the panel matters in a way it does not for the built-in Tux.
Honour the optional "logo-position", "logo-offset", "logo-centered" and
"logo-rotation" properties of the "linux,boot-logo-clut224" node.

The rotation is folded into the rotate argument at the entry points, so
fb_prepare_logo() reserves the right amount of space and fb_do_show_logo()
tiles in the same direction the image was rotated in.

Placement is applied after fb_rotate_logo(), since a rotation swaps the
image width and height and centring needs the final dimensions.

fb_prepare_logo() has to grow its reservation to cover wherever the logo
ends up, the way fb_center_logo already does: fbcon only leaves the first
n rows alone, so a logo placed further down is drawn and then immediately
cleared by the console.

"logo-centered" is deliberately close to the existing fb_center_logo, but
it is per device tree rather than per fbcon command line, and it composes
with "logo-offset" so that a logo can be centred and then nudged. That
combination is what panels with a partially visible area need, where the
usable region is not the centre of the mode.

Signed-off-by: Max Pedraza <maximpedraza@gmail.com>
---
 drivers/video/fbdev/core/fb_logo.c | 174 +++++++++++++++++++++++++++++
 1 file changed, 174 insertions(+)

diff --git a/drivers/video/fbdev/core/fb_logo.c b/drivers/video/fbdev/core/fb_logo.c
index 0bab8352b..bfc1b72ce 100644
--- a/drivers/video/fbdev/core/fb_logo.c
+++ b/drivers/video/fbdev/core/fb_logo.c
@@ -2,12 +2,178 @@
 
 #include <linux/fb.h>
 #include <linux/linux_logo.h>
+#include <linux/of.h>
 
 #include "fb_internal.h"
 
 bool fb_center_logo __read_mostly;
 int fb_logo_count __read_mostly = -1;
 
+#ifdef CONFIG_LOGO_DT_CLUT224
+
+/*
+ * Placement of a logo supplied by the device tree. The image itself is parsed
+ * by drivers/video/logo/logo.c, here we only care about where it goes.
+ */
+struct fb_logo_dt_placement {
+	bool valid;
+	bool centered;
+	bool has_position;
+	int rotation;		/* FB_ROTATE_*, or -1 when unspecified */
+	u32 x, y;
+	s32 offset_x, offset_y;
+};
+
+static struct fb_logo_dt_placement fb_logo_dt;
+
+static int fb_logo_dt_parse_rotation(const char *rotation)
+{
+	if (!strcmp(rotation, "none"))
+		return FB_ROTATE_UR;
+	if (!strcmp(rotation, "cw"))
+		return FB_ROTATE_CW;
+	if (!strcmp(rotation, "ud"))
+		return FB_ROTATE_UD;
+	if (!strcmp(rotation, "ccw"))
+		return FB_ROTATE_CCW;
+
+	return -EINVAL;
+}
+
+static void fb_logo_dt_read(void)
+{
+	struct fb_logo_dt_placement *p = &fb_logo_dt;
+	static bool read_done;
+	struct device_node *np;
+	const char *rotation;
+	u32 val[2];
+	int rot;
+
+	if (read_done)
+		return;
+
+	read_done = true;
+
+	np = of_find_compatible_node(NULL, NULL, "linux,boot-logo-clut224");
+	if (!np)
+		return;
+
+	if (!of_device_is_available(np))
+		goto out;
+
+	p->valid = true;
+	p->rotation = -1;
+	p->centered = of_property_read_bool(np, "logo-centered");
+
+	if (!of_property_read_u32_array(np, "logo-position", val, 2)) {
+		p->has_position = true;
+		p->x = val[0];
+		p->y = val[1];
+	}
+
+	if (!of_property_read_u32_array(np, "logo-offset", val, 2)) {
+		p->offset_x = (s32)val[0];
+		p->offset_y = (s32)val[1];
+	}
+
+	if (!of_property_read_string(np, "logo-rotation", &rotation)) {
+		rot = fb_logo_dt_parse_rotation(rotation);
+		if (rot < 0)
+			pr_warn("fb: %pOF: unknown logo-rotation \"%s\"\n",
+				np, rotation);
+		else
+			p->rotation = rot;
+	}
+
+out:
+	of_node_put(np);
+}
+
+static int fb_logo_dt_rotation(int rotate)
+{
+	fb_logo_dt_read();
+
+	if (fb_logo_dt.valid && fb_logo_dt.rotation >= 0)
+		return fb_logo_dt.rotation;
+
+	return rotate;
+}
+
+/* Top edge of the logo, in the coordinate space the caller works in */
+static int fb_logo_dt_top(unsigned int yres, unsigned int logo_height)
+{
+	struct fb_logo_dt_placement *p = &fb_logo_dt;
+	int top;
+
+	if (p->centered)
+		top = ((int)yres - (int)logo_height) / 2;
+	else if (p->has_position)
+		top = p->y;
+	else
+		top = 0;
+
+	return max(top + p->offset_y, 0);
+}
+
+static void fb_logo_dt_place(struct fb_info *info, struct fb_image *image)
+{
+	struct fb_logo_dt_placement *p = &fb_logo_dt;
+	int dx;
+
+	fb_logo_dt_read();
+
+	if (!p->valid)
+		return;
+
+	if (p->centered)
+		dx = ((int)info->var.xres - (int)image->width) / 2;
+	else if (p->has_position)
+		dx = p->x;
+	else
+		dx = image->dx;
+
+	image->dx = max(dx + p->offset_x, 0);
+	image->dy = fb_logo_dt_top(info->var.yres, image->height);
+}
+
+/*
+ * fbcon only leaves the first @height rows of the screen alone, so a logo
+ * placed further down would be drawn and then immediately cleared. Grow the
+ * reservation to cover wherever the logo actually ends up, the same way
+ * fb_center_logo does.
+ */
+static int fb_logo_dt_reserve(unsigned int yres, unsigned int logo_height,
+			      int height)
+{
+	fb_logo_dt_read();
+
+	if (!fb_logo_dt.valid)
+		return height;
+
+	return max(height, fb_logo_dt_top(yres, logo_height) +
+			   (int)logo_height);
+}
+
+#else /* !CONFIG_LOGO_DT_CLUT224 */
+
+static inline int fb_logo_dt_rotation(int rotate)
+{
+	return rotate;
+}
+
+static inline void fb_logo_dt_place(struct fb_info *info,
+				    struct fb_image *image)
+{
+}
+
+static inline int fb_logo_dt_reserve(unsigned int yres,
+				     unsigned int logo_height, int height)
+{
+	return height;
+}
+
+#endif /* CONFIG_LOGO_DT_CLUT224 */
+
 static inline unsigned int safe_shift(unsigned int d, int n)
 {
 	return n < 0 ? d >> -n : d << n;
@@ -350,6 +516,9 @@ static int fb_show_logo_line(struct fb_info *info, int rotate,
 			fb_rotate_logo(info, logo_rotate, &image, rotate);
 	}
 
+	/* Done last, image dimensions are only final after the rotation */
+	fb_logo_dt_place(info, &image);
+
 	fb_do_show_logo(info, &image, rotate, n);
 
 	kfree(palette);
@@ -423,6 +592,8 @@ int fb_prepare_logo(struct fb_info *info, int rotate)
 
 	memset(&fb_logo, 0, sizeof(struct logo_data));
 
+	rotate = fb_logo_dt_rotation(rotate);
+
 	if (info->flags & FBINFO_MISC_TILEBLITTING ||
 	    info->fbops->owner || !fb_logo_count)
 		return 0;
@@ -483,6 +654,7 @@ int fb_prepare_logo(struct fb_info *info, int rotate)
 	height = fb_logo.logo->height;
 	if (fb_center_logo)
 		height += (yres - fb_logo.logo->height) / 2;
+	height = fb_logo_dt_reserve(yres, fb_logo.logo->height, height);
 #ifdef CONFIG_FB_LOGO_EXTRA
 	height = fb_prepare_extra_logos(info, height, yres);
 #endif
@@ -498,6 +670,8 @@ int fb_show_logo(struct fb_info *info, int rotate)
 	if (!fb_logo_count)
 		return 0;
 
+	rotate = fb_logo_dt_rotation(rotate);
+
 	count = fb_logo_count < 0 ? num_online_cpus() : fb_logo_count;
 	y = fb_show_logo_line(info, rotate, fb_logo.logo, 0, count);
 #ifdef CONFIG_FB_LOGO_EXTRA
-- 
2.39.5

[RFC PATCH 4/6] dt-bindings: display: allow the boot logo in a reserved memory region

[Max Pedraza]

Carrying the image in the device tree ties it to the device tree, but the
image and where it goes on screen are independent axes of variation. One
board sold to several customers wants several device trees that differ in
the logo; one customer with several products built on that board wants the
same logo placed differently on each panel. The second case would otherwise
mean duplicating the same image into every device tree.

Let the node point at a reserved memory region filled in by the bootloader
instead, so one image can be shared by device trees that differ only in
placement. The region starts with a small header carrying a magic number
and the geometry, so the kernel can tell a logo from an empty or stale
region and bounds check everything against the reservation.

A phandle to a declared region is used rather than a bare address: the
reservation is what makes the memory safe to read and what gives the kernel
a size to validate against. The two ways of supplying the image are
mutually exclusive.

Signed-off-by: Max Pedraza <maximpedraza@gmail.com>
---
 .../display/linux,boot-logo-clut224.yaml      | 52 +++++++++++++++++--
 1 file changed, 48 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/linux,boot-logo-clut224.yaml b/Documentation/devicetree/bindings/display/linux,boot-logo-clut224.yaml
index 10845378d..c40683f3a 100644
--- a/Documentation/devicetree/bindings/display/linux,boot-logo-clut224.yaml
+++ b/Documentation/devicetree/bindings/display/linux,boot-logo-clut224.yaml
@@ -54,6 +54,23 @@ properties:
       index into the colour lookup table. The property length must be equal to
       width multiplied by height.
 
+  memory-region:
+    maxItems: 1
+    description: |
+      Reserved memory region holding the logo, as an alternative to carrying
+      it in the width, height, clut and data properties. The bootloader is
+      expected to have placed the image there before starting the kernel.
+
+      This lets one image be shared by several device trees that differ only
+      in where the logo goes, which is what a family of products built on the
+      same board but with different panels needs.
+
+      The region starts with a header of four little endian 32 bit words:
+      the magic number 0x4f474f4c ("LOGO"), the width, the height and the
+      number of palette entries. The palette follows, as consecutive red,
+      green and blue bytes per entry, and then one byte per pixel, each an
+      index into that palette.
+
   logo-position:
     $ref: /schemas/types.yaml#/definitions/uint32-array
     description:
@@ -85,10 +102,17 @@ properties:
 
 required:
   - compatible
-  - width
-  - height
-  - clut
-  - data
+
+# The image either lives in the device tree or in a reserved memory region,
+# never both.
+oneOf:
+  - required:
+      - width
+      - height
+      - clut
+      - data
+  - required:
+      - memory-region
 
 additionalProperties: false
 
@@ -106,3 +130,23 @@ examples:
                          0x02 0x00 0x00 0x02>;
         logo-centered;
     };
+  - |
+    // The same logo taken from a region the bootloader filled in, centred on
+    // a panel whose usable area is not the centre of the mode.
+    reserved-memory {
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges;
+
+        logo_mem: logo@9c000000 {
+            reg = <0x9c000000 0x100000>;
+            no-map;
+        };
+    };
+
+    logo {
+        compatible = "linux,boot-logo-clut224";
+        memory-region = <&logo_mem>;
+        logo-centered;
+        logo-offset = <0 120>;
+    };
-- 
2.39.5

[RFC PATCH 5/6] video: logo: allow the boot logo to come from a reserved memory region

[Max Pedraza]

Take the image from the region a "memory-region" phandle points at, when
the node has one, instead of from the width, height, clut and data
properties.

Only a declared region is accepted, never a bare physical address. That
matters for more than tidiness: the region is reserved before the allocator
starts, so the logo code can never be pointed at memory the kernel is using
for something else, and a size is known, so every field can be bounds
checked. The region is mapped with memremap(), which copes with a no-map
reservation and fails cleanly instead of handing back a bogus pointer the
way phys_to_virt() on an arbitrary address would.

The image is validated and copied out rather than used in place: the magic
number has to match, the geometry has to be sane, the palette and pixels
have to fit inside the reserved region, and every pixel has to reference an
existing palette entry. Anything else is reported and ignored, falling back
to the built-in logo. Copying also means nothing that happens to the region
afterwards can affect what has already been validated, and it keeps the
pixel data in the same shape both paths produce.

Signed-off-by: Max Pedraza <maximpedraza@gmail.com>
---
 drivers/video/logo/logo.c | 171 ++++++++++++++++++++++++++++++--------
 1 file changed, 135 insertions(+), 36 deletions(-)

diff --git a/drivers/video/logo/logo.c b/drivers/video/logo/logo.c
index b4f533df0..95d75b905 100644
--- a/drivers/video/logo/logo.c
+++ b/drivers/video/logo/logo.c
@@ -10,8 +10,10 @@
  *  Copyright (C) 2003 Geert Uytterhoeven <geert@linux-m68k.org>
  */
 
+#include <linux/io.h>
 #include <linux/linux_logo.h>
 #include <linux/of.h>
+#include <linux/of_reserved_mem.h>
 #include <linux/sizes.h>
 #include <linux/slab.h>
 #include <linux/stddef.h>
@@ -38,6 +40,15 @@ MODULE_PARM_DESC(nologo, "Disables startup logo");
 #define LOGO_DT_CLUT_OFFSET	32
 /* Sanity limit on the image size, a device tree is not a good place for more */
 #define LOGO_DT_MAX_PIXELS	SZ_32M
+/* "LOGO", little endian, at the start of a handed over memory region */
+#define LOGO_DT_MAGIC		0x4f474f4c
+
+struct logo_dt_header {
+	__le32 magic;
+	__le32 width;
+	__le32 height;
+	__le32 clutsize;
+};
 
 static struct linux_logo logo_dt_clut224 = {
 	.type		= LINUX_LOGO_CLUT224,
@@ -46,58 +57,41 @@ static struct linux_logo logo_dt_clut224 = {
 static unsigned char *logo_dt_clut;
 static unsigned char *logo_dt_data;
 
-static int logo_dt_parse(struct device_node *np)
+/* Reject geometries that cannot describe a sane image before using them */
+static int logo_dt_check_geometry(u32 width, u32 height, u32 clutsize)
 {
-	unsigned int clutsize, npixels, i;
-	unsigned char *clut, *data;
-	u32 width, height;
-	int len, ret;
-
-	ret = of_property_read_u32(np, "width", &width);
-	if (ret)
-		return ret;
-
-	ret = of_property_read_u32(np, "height", &height);
-	if (ret)
-		return ret;
-
 	if (!width || !height || (u64)width * height > LOGO_DT_MAX_PIXELS)
 		return -EINVAL;
 
-	npixels = width * height;
-
-	len = of_property_count_u8_elems(np, "clut");
-	if (len < 3 || len % 3)
+	if (!clutsize || clutsize > LOGO_DT_MAX_CLUT)
 		return -EINVAL;
 
-	clutsize = len / 3;
-	if (clutsize > LOGO_DT_MAX_CLUT)
-		return -EINVAL;
+	return 0;
+}
 
-	ret = of_property_count_u8_elems(np, "data");
-	if (ret < 0)
-		return ret;
-	if ((unsigned int)ret != npixels)
-		return -EINVAL;
+/*
+ * Take a private copy of an image that has already been range checked, so
+ * that nothing else can change it under us, and shift the pixels into the
+ * palette slots the frame buffer layer leaves to the logo.
+ */
+static int logo_dt_store(u32 width, u32 height, u32 clutsize,
+			 const u8 *clut_src, const u8 *data_src)
+{
+	unsigned int npixels = width * height;
+	unsigned char *clut, *data;
+	unsigned int i;
+	int ret;
 
-	clut = kmalloc(len, GFP_KERNEL);
+	clut = kmemdup(clut_src, clutsize * 3, GFP_KERNEL);
 	if (!clut)
 		return -ENOMEM;
 
-	data = kmalloc(npixels, GFP_KERNEL);
+	data = kmemdup(data_src, npixels, GFP_KERNEL);
 	if (!data) {
 		ret = -ENOMEM;
 		goto err_free_clut;
 	}
 
-	ret = of_property_read_u8_array(np, "clut", clut, len);
-	if (ret)
-		goto err_free_data;
-
-	ret = of_property_read_u8_array(np, "data", data, npixels);
-	if (ret)
-		goto err_free_data;
-
 	for (i = 0; i < npixels; i++) {
 		if (data[i] >= clutsize) {
 			ret = -ERANGE;
@@ -124,6 +118,111 @@ static int logo_dt_parse(struct device_node *np)
 	return ret;
 }
 
+static int logo_dt_parse_properties(struct device_node *np)
+{
+	const u8 *clut, *data;
+	u32 width, height;
+	int len, ret;
+
+	ret = of_property_read_u32(np, "width", &width);
+	if (ret)
+		return ret;
+
+	ret = of_property_read_u32(np, "height", &height);
+	if (ret)
+		return ret;
+
+	len = of_property_count_u8_elems(np, "clut");
+	if (len < 3 || len % 3)
+		return -EINVAL;
+
+	ret = logo_dt_check_geometry(width, height, len / 3);
+	if (ret)
+		return ret;
+
+	if (of_property_count_u8_elems(np, "data") != width * height)
+		return -EINVAL;
+
+	clut = of_get_property(np, "clut", NULL);
+	data = of_get_property(np, "data", NULL);
+	if (!clut || !data)
+		return -EINVAL;
+
+	return logo_dt_store(width, height, len / 3, clut, data);
+}
+
+/*
+ * Image handed over by the bootloader in a reserved memory region. Only a
+ * region the device tree declared is accepted, never a bare address, so the
+ * kernel can never be pointed at memory it is using for something else, and
+ * so that a size is known and every access can be bounds checked.
+ */
+static int logo_dt_parse_memory_region(struct device_node *np)
+{
+	u32 width, height, clutsize;
+	const struct logo_dt_header *hdr;
+	struct device_node *mem_np;
+	struct reserved_mem *rmem;
+	size_t clutlen, datalen;
+	const u8 *payload;
+	void *mem;
+	int ret;
+
+	mem_np = of_parse_phandle(np, "memory-region", 0);
+	if (!mem_np)
+		return -ENOENT;
+
+	rmem = of_reserved_mem_lookup(mem_np);
+	of_node_put(mem_np);
+	if (!rmem)
+		return -EINVAL;
+
+	if (rmem->size < sizeof(*hdr))
+		return -EINVAL;
+
+	mem = memremap(rmem->base, rmem->size, MEMREMAP_WB);
+	if (!mem)
+		return -ENOMEM;
+
+	hdr = mem;
+	if (le32_to_cpu(hdr->magic) != LOGO_DT_MAGIC) {
+		ret = -EINVAL;
+		goto out_unmap;
+	}
+
+	width = le32_to_cpu(hdr->width);
+	height = le32_to_cpu(hdr->height);
+	clutsize = le32_to_cpu(hdr->clutsize);
+
+	ret = logo_dt_check_geometry(width, height, clutsize);
+	if (ret)
+		goto out_unmap;
+
+	clutlen = (size_t)clutsize * 3;
+	datalen = (size_t)width * height;
+
+	/* Everything the header promises has to fit inside the region */
+	if (sizeof(*hdr) + clutlen + datalen > rmem->size) {
+		ret = -EINVAL;
+		goto out_unmap;
+	}
+
+	payload = (const u8 *)(hdr + 1);
+	ret = logo_dt_store(width, height, clutsize, payload, payload + clutlen);
+
+out_unmap:
+	memunmap(mem);
+	return ret;
+}
+
+static int logo_dt_parse(struct device_node *np)
+{
+	if (of_property_present(np, "memory-region"))
+		return logo_dt_parse_memory_region(np);
+
+	return logo_dt_parse_properties(np);
+}
+
 static const struct linux_logo *logo_dt_find(void)
 {
 	static bool probed;
-- 
2.39.5

[RFC PATCH 6/6] video: logo: add ppmtodtlogo host tool

[Max Pedraza]

The byte arrays a "linux,boot-logo-clut224" node carries are not meant to
be written by hand. Add a host tool that converts a PPM image into the
node, along the lines of the existing pnmtologo: plain C, no dependencies,
and no quantization of its own -- the image must already use at most 224
distinct colours, and the tool points at ImageMagick when it does not.

Three output flavours:

  ppmtodtlogo logo.ppm                  a complete overlay
  ppmtodtlogo -t dtsi logo.ppm          a bare node, for inclusion
  ppmtodtlogo -t bin -o logo.bin ...    the blob for a reserved memory
                                        region, header included

The devicetree outputs also carry the optional placement properties,
commented out unless requested on the command line, so the generated file
documents what can be tuned without regenerating the image.

The tool is built when CONFIG_LOGO_DT_CLUT224 is enabled but is not used
by the kernel build itself.

Signed-off-by: Max Pedraza <maximpedraza@gmail.com>
---
 drivers/video/logo/Makefile      |   6 +-
 drivers/video/logo/ppmtodtlogo.c | 402 +++++++++++++++++++++++++++++++
 2 files changed, 407 insertions(+), 1 deletion(-)
 create mode 100644 drivers/video/logo/ppmtodtlogo.c

diff --git a/drivers/video/logo/Makefile b/drivers/video/logo/Makefile
index 895c60b84..e7c77bf7e 100644
--- a/drivers/video/logo/Makefile
+++ b/drivers/video/logo/Makefile
@@ -18,7 +18,11 @@ obj-$(CONFIG_SPU_BASE)			+= logo_spe_clut224.o
 
 # How to generate logo's
 
-hostprogs := pnmtologo
+hostprogs := pnmtologo ppmtodtlogo
+
+# Not used by the build itself: converts a user's image into the devicetree
+# node or memory blob the "linux,boot-logo-clut224" binding consumes.
+always-$(CONFIG_LOGO_DT_CLUT224) += ppmtodtlogo
 
 # Create commands like "pnmtologo -t mono -n logo_mac_mono -o ..."
 quiet_cmd_logo = LOGO    $@
diff --git a/drivers/video/logo/ppmtodtlogo.c b/drivers/video/logo/ppmtodtlogo.c
new file mode 100644
index 000000000..de823131a
--- /dev/null
+++ b/drivers/video/logo/ppmtodtlogo.c
@@ -0,0 +1,402 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Convert a PPM image into a devicetree boot logo node, or into the binary
+ * blob the "linux,boot-logo-clut224" binding reads from a reserved memory
+ * region.
+ *
+ * Like pnmtologo, this tool does not quantize: the image must already use
+ * at most 224 distinct colours. Reduce it first if needed, for instance:
+ *
+ *	magick logo.png -colors 224 logo.ppm
+ *
+ * The devicetree output stores plain palette indices; the 32 entry offset
+ * the frame buffer layer reserves for the console is applied by the kernel.
+ */
+
+#include <ctype.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define MAX_CLUT_COLORS	224
+#define MAX_PIXELS	(32U * 1024 * 1024)
+#define BLOB_MAGIC	0x4f474f4cU	/* "LOGO", little endian */
+#define BYTES_PER_LINE	12
+
+static const char *programname;
+static const char *filename;
+static const char *outputname;
+static FILE *out;
+
+enum output_type {
+	OUTPUT_DTS,	/* complete overlay */
+	OUTPUT_DTSI,	/* bare node, for inclusion */
+	OUTPUT_BIN,	/* blob for a reserved memory region */
+};
+
+static enum output_type output_type = OUTPUT_DTS;
+
+/* Placement options, emitted into the node */
+static int opt_centered;
+static char *opt_position;
+static char *opt_offset;
+static const char *opt_rotation;
+
+struct color {
+	unsigned char red;
+	unsigned char green;
+	unsigned char blue;
+};
+
+static unsigned int logo_width;
+static unsigned int logo_height;
+static unsigned char *logo_data;
+static struct color logo_clut[MAX_CLUT_COLORS];
+static unsigned int logo_clutsize;
+
+static void die(const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	vfprintf(stderr, fmt, ap);
+	va_end(ap);
+	exit(1);
+}
+
+static void usage(void)
+{
+	die("Usage: %s [options] <filename>\n"
+	    "\n"
+	    "Convert a PPM image into a \"linux,boot-logo-clut224\" node.\n"
+	    "The image must use at most %d distinct colours.\n"
+	    "\n"
+	    "    -o <output>     write to file instead of stdout\n"
+	    "    -t <type>       dts (default), dtsi or bin\n"
+	    "    -c              centre the logo (logo-centered)\n"
+	    "    -p <x>,<y>      logo-position\n"
+	    "    -f <dx>,<dy>    logo-offset\n"
+	    "    -r <rotation>   logo-rotation: cw, ccw, ud or none\n"
+	    "    -h              this help\n",
+	    programname, MAX_CLUT_COLORS);
+}
+
+static unsigned int get_number(FILE *fp)
+{
+	int c;
+	unsigned int val;
+
+	/* Skip leading whitespace */
+	do {
+		c = fgetc(fp);
+		if (c == EOF)
+			die("%s: end of file\n", filename);
+		if (c == '#') {
+			/* Ignore comments 'till end of line */
+			do {
+				c = fgetc(fp);
+				if (c == EOF)
+					die("%s: end of file\n", filename);
+			} while (c != '\n');
+		}
+	} while (isspace(c));
+
+	if (!isdigit(c))
+		die("%s: expected a number\n", filename);
+
+	/* Parse decimal number */
+	val = 0;
+	while (isdigit(c)) {
+		val = 10 * val + c - '0';
+		c = fgetc(fp);
+		if (c == EOF)
+			break;
+	}
+	return val;
+}
+
+static unsigned char get_byte(FILE *fp)
+{
+	int c = fgetc(fp);
+
+	if (c == EOF)
+		die("%s: end of file\n", filename);
+	return c;
+}
+
+static unsigned int find_clut_entry(struct color color)
+{
+	unsigned int i;
+
+	for (i = 0; i < logo_clutsize; i++)
+		if (logo_clut[i].red == color.red &&
+		    logo_clut[i].green == color.green &&
+		    logo_clut[i].blue == color.blue)
+			return i;
+
+	if (logo_clutsize == MAX_CLUT_COLORS)
+		die("%s: more than %d colors, reduce the image first, e.g.\n"
+		    "    magick %s -colors %d out.ppm\n",
+		    filename, MAX_CLUT_COLORS, filename, MAX_CLUT_COLORS);
+
+	logo_clut[logo_clutsize] = color;
+	return logo_clutsize++;
+}
+
+static void read_image(void)
+{
+	unsigned int i, npixels, maxval;
+	int magic, raw;
+	FILE *fp;
+
+	fp = fopen(filename, "rb");
+	if (!fp)
+		die("Cannot open file %s: %s\n", filename, strerror(errno));
+
+	if (fgetc(fp) != 'P')
+		die("%s is not a PPM file\n", filename);
+
+	magic = fgetc(fp);
+	switch (magic) {
+	case '3':
+		raw = 0;
+		break;
+	case '6':
+		raw = 1;
+		break;
+	default:
+		die("%s is not a PPM file (only P3 and P6 are supported)\n",
+		    filename);
+	}
+
+	logo_width = get_number(fp);
+	logo_height = get_number(fp);
+	maxval = get_number(fp);
+	if (maxval != 255)
+		die("%s: maximum color value must be 255\n", filename);
+
+	if (!logo_width || !logo_height)
+		die("%s: zero sized image\n", filename);
+	if ((unsigned long long)logo_width * logo_height > MAX_PIXELS)
+		die("%s: image too large\n", filename);
+
+	npixels = logo_width * logo_height;
+	logo_data = malloc(npixels);
+	if (!logo_data)
+		die("%s\n", strerror(errno));
+
+	for (i = 0; i < npixels; i++) {
+		struct color color;
+
+		if (raw) {
+			color.red = get_byte(fp);
+			color.green = get_byte(fp);
+			color.blue = get_byte(fp);
+		} else {
+			color.red = get_number(fp);
+			color.green = get_number(fp);
+			color.blue = get_number(fp);
+		}
+		logo_data[i] = find_clut_entry(color);
+	}
+
+	fclose(fp);
+}
+
+static void write_bytes(const unsigned char *data, unsigned int len,
+			const char *indent)
+{
+	unsigned int i;
+
+	for (i = 0; i < len; i++) {
+		if (i % BYTES_PER_LINE == 0)
+			fprintf(out, "%s%s", i ? "\n" : "", indent);
+		else
+			fputc(' ', out);
+		fprintf(out, "0x%02x", data[i]);
+	}
+}
+
+static void write_placement(const char *indent)
+{
+	fprintf(out, "%s/* Placement. logo-centered and logo-position are exclusive;\n",
+		indent);
+	fprintf(out, "%s * logo-offset is added after either of the two. */\n",
+		indent);
+
+	fprintf(out, "%s%slogo-centered;\n", indent, opt_centered ? "" : "// ");
+	fprintf(out, "%s%slogo-position = <%s>;\n", indent,
+		opt_position ? "" : "// ", opt_position ? opt_position : "0 0");
+	fprintf(out, "%s%slogo-offset = <%s>;\n", indent,
+		opt_offset ? "" : "// ", opt_offset ? opt_offset : "0 0");
+	fprintf(out, "%s%slogo-rotation = \"%s\";\t/* cw, ccw, ud, none */\n",
+		indent, opt_rotation ? "" : "// ",
+		opt_rotation ? opt_rotation : "ccw");
+}
+
+static void write_node(const char *indent)
+{
+	char subindent[16];
+
+	snprintf(subindent, sizeof(subindent), "%s\t\t", indent);
+
+	fprintf(out, "%scompatible = \"linux,boot-logo-clut224\";\n", indent);
+	fprintf(out, "\n");
+	write_placement(indent);
+	fprintf(out, "\n");
+	fprintf(out, "%swidth = <%u>;\n", indent, logo_width);
+	fprintf(out, "%sheight = <%u>;\n", indent, logo_height);
+	fprintf(out, "\n");
+	fprintf(out, "%sclut = /bits/ 8 <", indent);
+	write_bytes((const unsigned char *)logo_clut, logo_clutsize * 3,
+		    subindent);
+	fprintf(out, ">;\n");
+	fprintf(out, "\n");
+	fprintf(out, "%sdata = /bits/ 8 <", indent);
+	write_bytes(logo_data, logo_width * logo_height, subindent);
+	fprintf(out, ">;\n");
+}
+
+static void write_header_comment(void)
+{
+	fprintf(out, "/*\n");
+	fprintf(out, " * Boot logo generated by ppmtodtlogo from %s\n",
+		filename);
+	fprintf(out, " * %ux%u pixels, %u colours.\n", logo_width, logo_height,
+		logo_clutsize);
+	fprintf(out, " */\n");
+}
+
+static void write_dts(void)
+{
+	fprintf(out, "/dts-v1/;\n/plugin/;\n\n");
+	write_header_comment();
+	fprintf(out, "\n");
+	fprintf(out, "/ {\n");
+	fprintf(out, "\tfragment@101 {\n");
+	fprintf(out, "\t\ttarget-path = \"/\";\n");
+	fprintf(out, "\n");
+	fprintf(out, "\t\t__overlay__ {\n");
+	fprintf(out, "\t\t\tlogo {\n");
+	write_node("\t\t\t\t");
+	fprintf(out, "\t\t\t};\n");
+	fprintf(out, "\t\t};\n");
+	fprintf(out, "\t};\n");
+	fprintf(out, "};\n");
+}
+
+static void write_dtsi(void)
+{
+	write_header_comment();
+	fprintf(out, "\n");
+	fprintf(out, "logo {\n");
+	write_node("\t");
+	fprintf(out, "};\n");
+}
+
+static void put_le32(unsigned int val)
+{
+	fputc(val & 0xff, out);
+	fputc((val >> 8) & 0xff, out);
+	fputc((val >> 16) & 0xff, out);
+	fputc((val >> 24) & 0xff, out);
+}
+
+static void write_bin(void)
+{
+	put_le32(BLOB_MAGIC);
+	put_le32(logo_width);
+	put_le32(logo_height);
+	put_le32(logo_clutsize);
+	fwrite(logo_clut, 3, logo_clutsize, out);
+	fwrite(logo_data, 1, logo_width * logo_height, out);
+}
+
+int main(int argc, char *argv[])
+{
+	int opt;
+	char *p;
+
+	programname = argv[0];
+
+	while ((opt = getopt(argc, argv, "o:t:cp:f:r:h")) != -1) {
+		switch (opt) {
+		case 'o':
+			outputname = optarg;
+			break;
+		case 't':
+			if (!strcmp(optarg, "dts"))
+				output_type = OUTPUT_DTS;
+			else if (!strcmp(optarg, "dtsi"))
+				output_type = OUTPUT_DTSI;
+			else if (!strcmp(optarg, "bin"))
+				output_type = OUTPUT_BIN;
+			else
+				usage();
+			break;
+		case 'c':
+			opt_centered = 1;
+			break;
+		case 'p':
+			opt_position = optarg;
+			break;
+		case 'f':
+			opt_offset = optarg;
+			break;
+		case 'r':
+			if (strcmp(optarg, "cw") && strcmp(optarg, "ccw") &&
+			    strcmp(optarg, "ud") && strcmp(optarg, "none"))
+				usage();
+			opt_rotation = optarg;
+			break;
+		default:
+			usage();
+		}
+	}
+	if (optind != argc - 1)
+		usage();
+	filename = argv[optind];
+
+	/* "10,20" and "10 20" are both accepted for -p and -f */
+	for (p = opt_position; p && *p; p++)
+		if (*p == ',')
+			*p = ' ';
+	for (p = opt_offset; p && *p; p++)
+		if (*p == ',')
+			*p = ' ';
+
+	read_image();
+
+	if (outputname) {
+		out = fopen(outputname,
+			    output_type == OUTPUT_BIN ? "wb" : "w");
+		if (!out)
+			die("Cannot create file %s: %s\n", outputname,
+			    strerror(errno));
+	} else {
+		out = stdout;
+	}
+
+	switch (output_type) {
+	case OUTPUT_DTS:
+		write_dts();
+		break;
+	case OUTPUT_DTSI:
+		write_dtsi();
+		break;
+	case OUTPUT_BIN:
+		write_bin();
+		break;
+	}
+
+	if (outputname)
+		fclose(out);
+
+	fprintf(stderr, "%s: %ux%u pixels, %u colours\n", filename, logo_width,
+		logo_height, logo_clutsize);
+
+	return 0;
+}
-- 
2.39.5