DRM uses FOURCC constants to describe pixel formats, fbdev uses a
per-component bitfield structure. The functions in this patch convert
between the two.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
drivers/gpu/drm/drm_fbconv_helper.c | 435 ++++++++++++++++++++++++++++
include/drm/drm_fbconv_helper.h | 23 ++
2 files changed, 458 insertions(+)
create mode 100644 include/drm/drm_fbconv_helper.h
diff --git a/drivers/gpu/drm/drm_fbconv_helper.c b/drivers/gpu/drm/drm_fbconv_helper.c
index 0cb46d2c98c3..af45358a156a 100644
--- a/drivers/gpu/drm/drm_fbconv_helper.c
+++ b/drivers/gpu/drm/drm_fbconv_helper.c
@@ -1 +1,436 @@
// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <asm/byteorder.h>
+
+#include <linux/fb.h>
+
+#include <drm/drm_fbconv_helper.h>
+
+/*
+ * Format conversion helpers
+ */
+
+static bool is_c8(const struct fb_var_screeninfo *fb_var)
+{
+ return fb_var->bits_per_pixel == 8;
+}
+
+static bool is_rgb565(const struct fb_var_screeninfo *fb_var)
+{
+ return (fb_var->bits_per_pixel == 16) &&
+ (fb_var->red.offset == 11) &&
+ (fb_var->red.length == 5) &&
+ (fb_var->green.offset == 5) &&
+ (fb_var->green.length == 6) &&
+ (fb_var->blue.offset == 0) &&
+ (fb_var->blue.length == 5);
+}
+
+static bool is_bgr565(const struct fb_var_screeninfo *fb_var)
+{
+ return (fb_var->bits_per_pixel == 16) &&
+ (fb_var->red.offset == 0) &&
+ (fb_var->red.length == 5) &&
+ (fb_var->green.offset == 5) &&
+ (fb_var->green.length == 6) &&
+ (fb_var->blue.offset == 11) &&
+ (fb_var->blue.length == 5);
+}
+
+static bool is_rgb888(const struct fb_var_screeninfo *fb_var)
+{
+ return (fb_var->bits_per_pixel == 24) &&
+ (fb_var->red.offset == 16) &&
+ (fb_var->red.length == 8) &&
+ (fb_var->green.offset == 8) &&
+ (fb_var->green.length == 8) &&
+ (fb_var->blue.offset == 0) &&
+ (fb_var->blue.length == 8);
+}
+
+static bool is_bgr888(const struct fb_var_screeninfo *fb_var)
+{
+ return (fb_var->bits_per_pixel == 24) &&
+ (fb_var->red.offset == 0) &&
+ (fb_var->red.length == 8) &&
+ (fb_var->green.offset == 8) &&
+ (fb_var->green.length == 8) &&
+ (fb_var->blue.offset == 16) &&
+ (fb_var->blue.length == 8);
+}
+
+static bool is_xrgb8888(const struct fb_var_screeninfo *fb_var)
+{
+ return (fb_var->bits_per_pixel == 32) &&
+ (fb_var->red.offset == 16) &&
+ (fb_var->red.length == 8) &&
+ (fb_var->green.offset == 8) &&
+ (fb_var->green.length == 8) &&
+ (fb_var->blue.offset == 0) &&
+ (fb_var->blue.length == 8) &&
+ (fb_var->transp.length == 0);
+}
+
+static bool is_xbgr8888(const struct fb_var_screeninfo *fb_var)
+{
+ return (fb_var->bits_per_pixel == 32) &&
+ (fb_var->red.offset == 0) &&
+ (fb_var->red.length == 8) &&
+ (fb_var->green.offset == 8) &&
+ (fb_var->green.length == 8) &&
+ (fb_var->blue.offset == 16) &&
+ (fb_var->blue.length == 8) &&
+ (fb_var->transp.length == 0);
+}
+
+static bool is_rgbx8888(const struct fb_var_screeninfo *fb_var)
+{
+ return (fb_var->bits_per_pixel == 32) &&
+ (fb_var->red.offset == 24) &&
+ (fb_var->red.length == 8) &&
+ (fb_var->green.offset == 16) &&
+ (fb_var->green.length == 8) &&
+ (fb_var->blue.offset == 8) &&
+ (fb_var->blue.length == 8) &&
+ (fb_var->transp.length == 0);
+}
+
+static bool is_bgrx8888(const struct fb_var_screeninfo *fb_var)
+{
+ return (fb_var->bits_per_pixel == 32) &&
+ (fb_var->red.offset == 8) &&
+ (fb_var->red.length == 8) &&
+ (fb_var->green.offset == 16) &&
+ (fb_var->green.length == 8) &&
+ (fb_var->blue.offset == 24) &&
+ (fb_var->blue.length == 8) &&
+ (fb_var->transp.length == 0);
+}
+
+static bool is_argb8888(const struct fb_var_screeninfo *fb_var)
+{
+ return (fb_var->bits_per_pixel == 32) &&
+ (fb_var->red.offset == 16) &&
+ (fb_var->red.length == 8) &&
+ (fb_var->green.offset == 8) &&
+ (fb_var->green.length == 8) &&
+ (fb_var->blue.offset == 0) &&
+ (fb_var->blue.length == 8) &&
+ (fb_var->transp.offset == 24) &&
+ (fb_var->transp.length == 8);
+}
+
+static bool is_abgr8888(const struct fb_var_screeninfo *fb_var)
+{
+ return (fb_var->bits_per_pixel == 32) &&
+ (fb_var->red.offset == 0) &&
+ (fb_var->red.length == 8) &&
+ (fb_var->green.offset == 8) &&
+ (fb_var->green.length == 8) &&
+ (fb_var->blue.offset == 16) &&
+ (fb_var->blue.length == 8) &&
+ (fb_var->transp.offset == 24) &&
+ (fb_var->transp.length == 8);
+}
+
+static bool is_rgba8888(const struct fb_var_screeninfo *fb_var)
+{
+ return (fb_var->bits_per_pixel == 32) &&
+ (fb_var->red.offset == 24) &&
+ (fb_var->red.length == 8) &&
+ (fb_var->green.offset == 16) &&
+ (fb_var->green.length == 8) &&
+ (fb_var->blue.offset == 8) &&
+ (fb_var->blue.length == 8) &&
+ (fb_var->transp.offset == 0) &&
+ (fb_var->transp.length == 8);
+}
+
+static bool is_bgra8888(const struct fb_var_screeninfo *fb_var)
+{
+ return (fb_var->bits_per_pixel == 32) &&
+ (fb_var->red.offset == 8) &&
+ (fb_var->red.length == 8) &&
+ (fb_var->green.offset == 16) &&
+ (fb_var->green.length == 8) &&
+ (fb_var->blue.offset == 24) &&
+ (fb_var->blue.length == 8) &&
+ (fb_var->transp.offset == 0) &&
+ (fb_var->transp.length == 8);
+}
+
+struct format_map {
+ bool (*is_format)(const struct fb_var_screeninfo *fb_var);
+ uint32_t format;
+};
+
+/**
+ * drm_fbconv_format_of_fb_var_screeninfo - Returns a DRM_FORMAT constant
+ * from an fb_var_screeninfo structure
+ * @fb_info: the fb_var_screeninfo structure
+ * Returns:
+ * A DRM_FORMAT constant on success, or
+ * DRM_FORMAT_INVALID otherwise.
+ */
+uint32_t
+drm_fbconv_format_of_fb_var_screeninfo(const struct fb_var_screeninfo *fb_var)
+{
+ static const struct format_map map[] = {
+ { is_c8, DRM_FORMAT_C8 }, /* 256-color palette */
+ { is_rgb565, DRM_FORMAT_RGB565 },
+ { is_bgr565, DRM_FORMAT_BGR565 },
+ { is_rgb888, DRM_FORMAT_RGB888 },
+ { is_bgr888, DRM_FORMAT_BGR888 },
+ { is_xrgb8888, DRM_FORMAT_XRGB8888 },
+ { is_xbgr8888, DRM_FORMAT_XBGR8888 },
+ { is_rgbx8888, DRM_FORMAT_RGBX8888 },
+ { is_bgrx8888, DRM_FORMAT_BGRX8888 },
+ { is_argb8888, DRM_FORMAT_ARGB8888 },
+ { is_abgr8888, DRM_FORMAT_ABGR8888 },
+ { is_rgba8888, DRM_FORMAT_RGBA8888 },
+ { is_bgra8888, DRM_FORMAT_BGRA8888 }
+ };
+
+ size_t i;
+
+ if (fb_var->bits_per_pixel < 8)
+ goto err; /* at least 8-bit color required */
+ if (fb_var->grayscale == 1)
+ goto err; /* grayscale output is not supported */
+
+ for (i = 0; i < ARRAY_SIZE(map); ++i) {
+ if (map[i].is_format(fb_var))
+ return map[i].format;
+ }
+
+err:
+ return DRM_FORMAT_INVALID;
+}
+EXPORT_SYMBOL(drm_fbconv_format_of_fb_var_screeninfo);
+
+/**
+ * drm_fbconv_format_of_fb_info - Returns a DRM_FORMAT constant from
+ * an fb_info structure
+ * @fb_info: the fb_info structure
+ * Returns:
+ * A DRM_FORMAT constant on success, or
+ * DRM_FORMAT_INVALID otherwise.
+ */
+uint32_t drm_fbconv_format_of_fb_info(const struct fb_info *fb_info)
+{
+ if (fb_info->fix.type != FB_TYPE_PACKED_PIXELS)
+ return DRM_FORMAT_INVALID; /* no multi-plane formats */
+
+ return drm_fbconv_format_of_fb_var_screeninfo(&fb_info->var);
+}
+EXPORT_SYMBOL(drm_fbconv_format_of_fb_info);
+
+static void set_fb_bitfield(struct fb_bitfield *bits, __u32 offset,
+ __u32 length)
+{
+ bits->offset = offset;
+ bits->length = length;
+ bits->msb_right = 0;
+}
+
+static void set_c8(struct fb_var_screeninfo *fb_var)
+{
+ fb_var->bits_per_pixel = 8;
+ fb_var->grayscale = 0;
+ set_fb_bitfield(&fb_var->red, 0, 8);
+ set_fb_bitfield(&fb_var->green, 0, 8);
+ set_fb_bitfield(&fb_var->blue, 0, 8);
+ set_fb_bitfield(&fb_var->transp, 0, 0);
+ fb_var->nonstd = 0;
+}
+
+static void set_rgb565(struct fb_var_screeninfo *fb_var)
+{
+ fb_var->bits_per_pixel = 16;
+ fb_var->grayscale = 0;
+ set_fb_bitfield(&fb_var->red, 11, 5);
+ set_fb_bitfield(&fb_var->green, 5, 6);
+ set_fb_bitfield(&fb_var->blue, 0, 5);
+ set_fb_bitfield(&fb_var->transp, 0, 0);
+ fb_var->nonstd = 0;
+}
+
+static void set_bgr565(struct fb_var_screeninfo *fb_var)
+{
+ fb_var->bits_per_pixel = 16;
+ fb_var->grayscale = 0;
+ set_fb_bitfield(&fb_var->red, 0, 5);
+ set_fb_bitfield(&fb_var->green, 5, 6);
+ set_fb_bitfield(&fb_var->blue, 11, 5);
+ set_fb_bitfield(&fb_var->transp, 0, 0);
+ fb_var->nonstd = 0;
+}
+
+static void set_rgb888(struct fb_var_screeninfo *fb_var)
+{
+ fb_var->bits_per_pixel = 24;
+ fb_var->grayscale = 0;
+ set_fb_bitfield(&fb_var->red, 16, 8);
+ set_fb_bitfield(&fb_var->green, 8, 8);
+ set_fb_bitfield(&fb_var->blue, 0, 8);
+ set_fb_bitfield(&fb_var->transp, 0, 0);
+ fb_var->nonstd = 0;
+}
+
+static void set_bgr888(struct fb_var_screeninfo *fb_var)
+{
+ fb_var->bits_per_pixel = 24;
+ fb_var->grayscale = 0;
+ set_fb_bitfield(&fb_var->red, 0, 8);
+ set_fb_bitfield(&fb_var->green, 8, 8);
+ set_fb_bitfield(&fb_var->blue, 16, 8);
+ set_fb_bitfield(&fb_var->transp, 0, 0);
+ fb_var->nonstd = 0;
+}
+
+static void set_xrgb8888(struct fb_var_screeninfo *fb_var)
+{
+ fb_var->bits_per_pixel = 32;
+ fb_var->grayscale = 0;
+ set_fb_bitfield(&fb_var->red, 16, 8);
+ set_fb_bitfield(&fb_var->green, 8, 8);
+ set_fb_bitfield(&fb_var->blue, 0, 8);
+ set_fb_bitfield(&fb_var->transp, 24, 0);
+ fb_var->nonstd = 0;
+}
+
+static void set_xbgr8888(struct fb_var_screeninfo *fb_var)
+{
+ fb_var->bits_per_pixel = 32;
+ fb_var->grayscale = 0;
+ set_fb_bitfield(&fb_var->red, 0, 8);
+ set_fb_bitfield(&fb_var->green, 8, 8);
+ set_fb_bitfield(&fb_var->blue, 16, 8);
+ set_fb_bitfield(&fb_var->transp, 24, 0);
+ fb_var->nonstd = 0;
+}
+
+static void set_rgbx8888(struct fb_var_screeninfo *fb_var)
+{
+ fb_var->bits_per_pixel = 32;
+ fb_var->grayscale = 0;
+ set_fb_bitfield(&fb_var->red, 24, 8);
+ set_fb_bitfield(&fb_var->green, 16, 8);
+ set_fb_bitfield(&fb_var->blue, 8, 8);
+ set_fb_bitfield(&fb_var->transp, 0, 0);
+ fb_var->nonstd = 0;
+}
+
+static void set_bgrx8888(struct fb_var_screeninfo *fb_var)
+{
+ fb_var->bits_per_pixel = 32;
+ fb_var->grayscale = 0;
+ set_fb_bitfield(&fb_var->red, 8, 8);
+ set_fb_bitfield(&fb_var->green, 16, 8);
+ set_fb_bitfield(&fb_var->blue, 24, 8);
+ set_fb_bitfield(&fb_var->transp, 0, 0);
+ fb_var->nonstd = 0;
+}
+
+static void set_argb8888(struct fb_var_screeninfo *fb_var)
+{
+ fb_var->bits_per_pixel = 32;
+ fb_var->grayscale = 0;
+ set_fb_bitfield(&fb_var->red, 16, 8);
+ set_fb_bitfield(&fb_var->green, 8, 8);
+ set_fb_bitfield(&fb_var->blue, 0, 8);
+ set_fb_bitfield(&fb_var->transp, 24, 8);
+ fb_var->nonstd = 0;
+}
+
+static void set_abgr8888(struct fb_var_screeninfo *fb_var)
+{
+ fb_var->bits_per_pixel = 32;
+ fb_var->grayscale = 0;
+ set_fb_bitfield(&fb_var->red, 0, 8);
+ set_fb_bitfield(&fb_var->green, 8, 8);
+ set_fb_bitfield(&fb_var->blue, 16, 8);
+ set_fb_bitfield(&fb_var->transp, 24, 8);
+ fb_var->nonstd = 0;
+}
+
+static void set_rgba8888(struct fb_var_screeninfo *fb_var)
+{
+ fb_var->bits_per_pixel = 32;
+ fb_var->grayscale = 0;
+ set_fb_bitfield(&fb_var->red, 24, 8);
+ set_fb_bitfield(&fb_var->green, 16, 8);
+ set_fb_bitfield(&fb_var->blue, 8, 8);
+ set_fb_bitfield(&fb_var->transp, 0, 8);
+ fb_var->nonstd = 0;
+}
+
+static void set_bgra8888(struct fb_var_screeninfo *fb_var)
+{
+ fb_var->bits_per_pixel = 32;
+ fb_var->grayscale = 0;
+ set_fb_bitfield(&fb_var->red, 8, 8);
+ set_fb_bitfield(&fb_var->green, 16, 8);
+ set_fb_bitfield(&fb_var->blue, 24, 8);
+ set_fb_bitfield(&fb_var->transp, 0, 8);
+ fb_var->nonstd = 0;
+}
+
+/**
+ * drm_fbconv_update_fb_var_screen_info_from_format - sets the pixel format
+ * of a fb_var_screeninfo structure from a DRM_FORMAT constant
+ * @fb_var: the fb_var_screeninfo structure to update
+ * @format: a DRM_FORMAT constant
+ * Returns:
+ * 0 on success, or
+ * a negative error code otherwise.
+ */
+int drm_fbconv_update_fb_var_screeninfo_from_format(
+ struct fb_var_screeninfo *fb_var, uint32_t format)
+{
+ switch (format) {
+ case DRM_FORMAT_C8:
+ set_c8(fb_var);
+ break;
+ case DRM_FORMAT_RGB565:
+ set_rgb565(fb_var);
+ break;
+ case DRM_FORMAT_BGR565:
+ set_bgr565(fb_var);
+ break;
+ case DRM_FORMAT_RGB888:
+ set_rgb888(fb_var);
+ break;
+ case DRM_FORMAT_BGR888:
+ set_bgr888(fb_var);
+ break;
+ case DRM_FORMAT_XRGB8888:
+ set_xrgb8888(fb_var);
+ break;
+ case DRM_FORMAT_XBGR8888:
+ set_xbgr8888(fb_var);
+ break;
+ case DRM_FORMAT_RGBX8888:
+ set_rgbx8888(fb_var);
+ break;
+ case DRM_FORMAT_BGRX8888:
+ set_bgrx8888(fb_var);
+ break;
+ case DRM_FORMAT_ARGB8888:
+ set_argb8888(fb_var);
+ break;
+ case DRM_FORMAT_ABGR8888:
+ set_abgr8888(fb_var);
+ break;
+ case DRM_FORMAT_RGBA8888:
+ set_rgba8888(fb_var);
+ break;
+ case DRM_FORMAT_BGRA8888:
+ set_bgra8888(fb_var);
+ break;
+ default:
+ return -EINVAL;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(drm_fbconv_update_fb_var_screeninfo_from_format);
diff --git a/include/drm/drm_fbconv_helper.h b/include/drm/drm_fbconv_helper.h
new file mode 100644
index 000000000000..6b2ed12b579a
--- /dev/null
+++ b/include/drm/drm_fbconv_helper.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef DRM_FBCONV_HELPER_H
+#define DRM_FBCONV_HELPER_H
+
+#include <drm/drm_fourcc.h>
+
+struct fb_info;
+struct fb_var_screeninfo;
+
+/*
+ * Format conversion helpers
+ */
+
+uint32_t
+drm_fbconv_format_of_fb_var_screeninfo(const struct fb_var_screeninfo *fb_var);
+
+uint32_t drm_fbconv_format_of_fb_info(const struct fb_info *fb_info);
+
+int drm_fbconv_update_fb_var_screeninfo_from_format(
+ struct fb_var_screeninfo *fb_var, uint32_t format);
+
+#endif
--
2.23.0
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