drm/eld: add helpers to modify the SADs of an ELD

Occasionally it's necessary for drivers to modify the SADs of an ELD,
but it's not so cool to have drivers poke at the ELD buffer directly.

Using the helpers to translate between 3-byte SAD and struct cea_sad,
add ELD helpers to get/set the SADs from/to an ELD.

v2: s/i/sad_index/ (Mitul)

Cc: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/8e9a05f2b1e0dd184132d636e1e778e8917ec25d.1698747331.git.jani.nikula@intel.com

diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-kms-helpers.rst
index cfa8e6c399b649fc86c5713eccb30383238b6241..59cfe8a7a8bace8e24d2f032e59084e06ddca557 100644 (file)
--- a/Documentation/gpu/drm-kms-helpers.rst
+++ b/Documentation/gpu/drm-kms-helpers.rst
@@ -366,6 +366,9 @@ EDID Helper Functions Reference
 .. kernel-doc:: include/drm/drm_eld.h
    :internal:
 
+.. kernel-doc:: drivers/gpu/drm/drm_eld.c
+   :export:
+
 SCDC Helper Functions Reference
 ===============================
 

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 8e1bde059170ed4ad033ce97756a3570175ec665..cdbe91ac0bfc8f7e2ad7a1d4d1729738f9943499 100644 (file)
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -22,6 +22,7 @@ drm-y := \
        drm_drv.o \
        drm_dumb_buffers.o \
        drm_edid.o \
+       drm_eld.o \
        drm_encoder.o \
        drm_file.o \
        drm_fourcc.o \

diff --git a/drivers/gpu/drm/drm_eld.c b/drivers/gpu/drm/drm_eld.c
new file mode 100644 (file)
index 0000000..5177991
--- /dev/null
+++ b/drivers/gpu/drm/drm_eld.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2023 Intel Corporation
+ */
+
+#include <drm/drm_edid.h>
+#include <drm/drm_eld.h>
+
+#include "drm_internal.h"
+
+/**
+ * drm_eld_sad_get - get SAD from ELD to struct cea_sad
+ * @eld: ELD buffer
+ * @sad_index: SAD index
+ * @cta_sad: destination struct cea_sad
+ *
+ * @return: 0 on success, or negative on errors
+ */
+int drm_eld_sad_get(const u8 *eld, int sad_index, struct cea_sad *cta_sad)
+{
+       const u8 *sad;
+
+       if (sad_index >= drm_eld_sad_count(eld))
+               return -EINVAL;
+
+       sad = eld + DRM_ELD_CEA_SAD(drm_eld_mnl(eld), sad_index);
+
+       drm_edid_cta_sad_set(cta_sad, sad);
+
+       return 0;
+}
+EXPORT_SYMBOL(drm_eld_sad_get);
+
+/**
+ * drm_eld_sad_set - set SAD to ELD from struct cea_sad
+ * @eld: ELD buffer
+ * @sad_index: SAD index
+ * @cta_sad: source struct cea_sad
+ *
+ * @return: 0 on success, or negative on errors
+ */
+int drm_eld_sad_set(u8 *eld, int sad_index, const struct cea_sad *cta_sad)
+{
+       u8 *sad;
+
+       if (sad_index >= drm_eld_sad_count(eld))
+               return -EINVAL;
+
+       sad = eld + DRM_ELD_CEA_SAD(drm_eld_mnl(eld), sad_index);
+
+       drm_edid_cta_sad_get(cta_sad, sad);
+
+       return 0;
+}
+EXPORT_SYMBOL(drm_eld_sad_set);

diff --git a/include/drm/drm_eld.h b/include/drm/drm_eld.h
index 7b674256b9aa0e779e42b7d56e7af966e723d962..0a88d10b28b037a55ce31cd5fa700cd9cf038c7a 100644 (file)
--- a/include/drm/drm_eld.h
+++ b/include/drm/drm_eld.h
@@ -8,6 +8,8 @@
 
 #include <linux/types.h>
 
+struct cea_sad;
+
 /* ELD Header Block */
 #define DRM_ELD_HEADER_BLOCK_SIZE      4
 
@@ -75,6 +77,9 @@ static inline int drm_eld_mnl(const u8 *eld)
        return (eld[DRM_ELD_CEA_EDID_VER_MNL] & DRM_ELD_MNL_MASK) >> DRM_ELD_MNL_SHIFT;
 }
 
+int drm_eld_sad_get(const u8 *eld, int sad_index, struct cea_sad *cta_sad);
+int drm_eld_sad_set(u8 *eld, int sad_index, const struct cea_sad *cta_sad);
+
 /**
  * drm_eld_sad - Get ELD SAD structures.
  * @eld: pointer to an eld memory structure with sad_count set