[PATCH v2 4/4] drm/format-helper: Add drm_fb_build_fourcc_list() helper
Thomas Zimmermann
tzimmermann at suse.de
Tue Aug 16 13:48:53 UTC 2022
Add drm_fb_build_fourcc_list() function that builds a list of supported
formats from native and emulated ones. Helpful for all drivers that do
format conversion as part of their plane updates. Update current caller.
v2:
* use u32 instead of uint32_t (Sam)
* print a warning if output array is too small (Sam)
* comment fixes (Sam)
Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
Reviewed-by: Sam Ravnborg <sam at ravnborg.org>
---
drivers/gpu/drm/drm_format_helper.c | 103 ++++++++++++++++++++++++++++
drivers/gpu/drm/tiny/simpledrm.c | 47 ++-----------
include/drm/drm_format_helper.h | 11 ++-
3 files changed, 118 insertions(+), 43 deletions(-)
diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index 56642816fdff..fe1db7dbda3f 100644
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -793,3 +793,106 @@ void drm_fb_xrgb8888_to_mono(struct iosys_map *dst, const unsigned int *dst_pitc
kfree(src32);
}
EXPORT_SYMBOL(drm_fb_xrgb8888_to_mono);
+
+static bool is_listed_fourcc(const uint32_t *fourccs, size_t nfourccs, uint32_t fourcc)
+{
+ const uint32_t *fourccs_end = fourccs + nfourccs;
+
+ while (fourccs < fourccs_end) {
+ if (*fourccs == fourcc)
+ return true;
+ ++fourccs;
+ }
+ return false;
+}
+
+/**
+ * drm_fb_build_fourcc_list - Filters a list of supported color formats against
+ * the device's native formats
+ * @dev: DRM device
+ * @native_fourccs: 4CC codes of natively supported color formats
+ * @native_nfourccs: The number of entries in @native_fourccs
+ * @extra_fourccs: 4CC codes of additionally supported color formats
+ * @extra_nfourccs: The number of entries in @extra_fourccs
+ * @fourccs_out: Returns 4CC codes of supported color formats
+ * @nfourccs_out: The number of available entries in @fourccs_out
+ *
+ * This function create a list of supported color format from natively
+ * supported formats and the emulated formats.
+ * At a minimum, most userspace programs expect at least support for
+ * XRGB8888 on the primary plane. Devices that have to emulate the
+ * format, and possibly others, can use drm_fb_build_fourcc_list() to
+ * create a list of supported color formats. The returned list can
+ * be handed over to drm_universal_plane_init() et al. Native formats
+ * will go before emulated formats. Other heuristics might be applied
+ * to optimize the order. Formats near the beginning of the list are
+ * usually preferred over formats near the end of the list.
+ *
+ * Returns:
+ * The number of color-formats 4CC codes returned in @fourccs_out.
+ */
+size_t drm_fb_build_fourcc_list(struct drm_device *dev,
+ const u32 *native_fourccs, size_t native_nfourccs,
+ const u32 *extra_fourccs, size_t extra_nfourccs,
+ u32 *fourccs_out, size_t nfourccs_out)
+{
+ u32 *fourccs = fourccs_out;
+ const u32 *fourccs_end = fourccs_out + nfourccs_out;
+ bool found_native = false;
+ size_t nfourccs, i;
+
+ /*
+ * The device's native formats go first.
+ */
+
+ nfourccs = min_t(size_t, native_nfourccs, nfourccs_out);
+
+ for (i = 0; i < nfourccs; ++i) {
+ u32 fourcc = native_fourccs[i];
+
+ drm_dbg_kms(dev, "adding native format %p4cc\n", &fourcc);
+
+ if (!found_native)
+ found_native = is_listed_fourcc(extra_fourccs, extra_nfourccs, fourcc);
+ *fourccs = fourcc;
+ ++fourccs;
+ }
+
+ /*
+ * The plane's atomic_update helper converts the framebuffer's color format
+ * to a native format when copying to device memory.
+ *
+ * If there is not a single format supported by both, device and
+ * driver, the native formats are likely not supported by the conversion
+ * helpers. Therefore *only* support the native formats and add a
+ * conversion helper ASAP.
+ */
+ if (!found_native) {
+ drm_warn(dev, "Format conversion helpers required to add extra formats.\n");
+ goto out;
+ }
+
+ /*
+ * The extra formats, emulated by the driver, go second.
+ */
+
+ nfourccs = min_t(size_t, extra_nfourccs, fourccs_end - fourccs);
+
+ for (i = 0; i < nfourccs; ++i) {
+ u32 fourcc = extra_fourccs[i];
+
+ if (is_listed_fourcc(native_fourccs, native_nfourccs, fourcc))
+ continue; /* native formats already went first */
+ *fourccs = fourcc;
+ ++fourccs;
+ }
+
+ if (nfourccs < extra_nfourccs) {
+ drm_warn(dev, "Format buffer too small. %zu trailing formats dropped.\n",
+ extra_nfourccs - nfourccs);
+ }
+
+out:
+ return fourccs - fourccs_out;
+}
+EXPORT_SYMBOL(drm_fb_build_fourcc_list);
diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simpledrm.c
index 404290760c60..777ccd250871 100644
--- a/drivers/gpu/drm/tiny/simpledrm.c
+++ b/drivers/gpu/drm/tiny/simpledrm.c
@@ -644,45 +644,6 @@ static struct drm_display_mode simpledrm_mode(unsigned int width,
return mode;
}
-static const uint32_t *simpledrm_device_formats(struct simpledrm_device *sdev,
- size_t *nformats_out)
-{
- struct drm_device *dev = &sdev->dev;
- size_t i;
-
- if (sdev->nformats)
- goto out; /* don't rebuild list on recurring calls */
-
- /* native format goes first */
- sdev->formats[0] = sdev->format->format;
- sdev->nformats = 1;
-
- /* default formats go second */
- for (i = 0; i < ARRAY_SIZE(simpledrm_primary_plane_formats); ++i) {
- if (simpledrm_primary_plane_formats[i] == sdev->format->format)
- continue; /* native format already went first */
- sdev->formats[sdev->nformats] = simpledrm_primary_plane_formats[i];
- sdev->nformats++;
- }
-
- /*
- * TODO: The simpledrm driver converts framebuffers to the native
- * format when copying them to device memory. If there are more
- * formats listed than supported by the driver, the native format
- * is not supported by the conversion helpers. Therefore *only*
- * support the native format and add a conversion helper ASAP.
- */
- if (drm_WARN_ONCE(dev, i != sdev->nformats,
- "format conversion helpers required for %p4cc",
- &sdev->format->format)) {
- sdev->nformats = 1;
- }
-
-out:
- *nformats_out = sdev->nformats;
- return sdev->formats;
-}
-
static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv,
struct platform_device *pdev)
{
@@ -699,7 +660,6 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv,
struct drm_encoder *encoder;
struct drm_connector *connector;
unsigned long max_width, max_height;
- const uint32_t *formats;
size_t nformats;
int ret;
@@ -811,11 +771,14 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv,
/* Primary plane */
- formats = simpledrm_device_formats(sdev, &nformats);
+ nformats = drm_fb_build_fourcc_list(dev, &format->format, 1,
+ simpledrm_primary_plane_formats,
+ ARRAY_SIZE(simpledrm_primary_plane_formats),
+ sdev->formats, ARRAY_SIZE(sdev->formats));
primary_plane = &sdev->primary_plane;
ret = drm_universal_plane_init(dev, primary_plane, 0, &simpledrm_primary_plane_funcs,
- formats, nformats,
+ sdev->formats, nformats,
simpledrm_primary_plane_format_modifiers,
DRM_PLANE_TYPE_PRIMARY, NULL);
if (ret)
diff --git a/include/drm/drm_format_helper.h b/include/drm/drm_format_helper.h
index caa181194335..eb5c98cf82b8 100644
--- a/include/drm/drm_format_helper.h
+++ b/include/drm/drm_format_helper.h
@@ -6,11 +6,15 @@
#ifndef __LINUX_DRM_FORMAT_HELPER_H
#define __LINUX_DRM_FORMAT_HELPER_H
-struct iosys_map;
+#include <linux/types.h>
+
+struct drm_device;
struct drm_format_info;
struct drm_framebuffer;
struct drm_rect;
+struct iosys_map;
+
unsigned int drm_fb_clip_offset(unsigned int pitch, const struct drm_format_info *format,
const struct drm_rect *clip);
@@ -44,4 +48,9 @@ void drm_fb_xrgb8888_to_mono(struct iosys_map *dst, const unsigned int *dst_pitc
const struct iosys_map *src, const struct drm_framebuffer *fb,
const struct drm_rect *clip);
+size_t drm_fb_build_fourcc_list(struct drm_device *dev,
+ const u32 *native_fourccs, size_t native_nfourccs,
+ const u32 *extra_fourccs, size_t extra_nfourccs,
+ u32 *fourccs_out, size_t nfourccs_out);
+
#endif /* __LINUX_DRM_FORMAT_HELPER_H */
--
2.37.1
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