[PATCH RFC 2/4] ALSA: hda: Make CEA channel allocation interfaces const

[Cássio Gabriel]

The CEA channel allocation descriptors are initialized once and only
read by the HDA channel-map helpers and codec-specific callbacks.

Qualify the pointers passed through these interfaces as const. This
makes their read-only contract explicit and prepares the interfaces for
using an immutable common allocation table.

Signed-off-by: Cássio Gabriel <cassiogabrielcontato@xxxxxxxxx>
---
 include/sound/hda_chmap.h         |  8 +++++---
 sound/hda/codecs/hdmi/atihdmi.c   |  6 +++---
 sound/hda/codecs/hdmi/nvhdmi.c    |  3 ++-
 sound/hda/codecs/hdmi/tegrahdmi.c |  3 ++-
 sound/hda/core/hdmi_chmap.c       | 12 +++++++-----
 5 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/include/sound/hda_chmap.h b/include/sound/hda_chmap.h
index e508f3192294..b539595fd5cd 100644
--- a/include/sound/hda_chmap.h
+++ b/include/sound/hda_chmap.h
@@ -28,9 +28,10 @@ struct hdac_chmap_ops {
 	 * for devices that have non-standard mapping requirements.
 	 */
 	int (*chmap_cea_alloc_validate_get_type)(struct hdac_chmap *chmap,
-		struct hdac_cea_channel_speaker_allocation *cap, int channels);
+		const struct hdac_cea_channel_speaker_allocation *cap,
+		int channels);
 	void (*cea_alloc_to_tlv_chmap)(struct hdac_chmap *hchmap,
-		struct hdac_cea_channel_speaker_allocation *cap,
+		const struct hdac_cea_channel_speaker_allocation *cap,
 		unsigned int *chmap, int channels);
 
 	/* check that the user-given chmap is supported */
@@ -71,7 +72,8 @@ void snd_hdac_setup_channel_mapping(struct hdac_chmap *chmap,
 		       int channels, unsigned char *map,
 		       bool chmap_set);
 void snd_hdac_print_channel_allocation(int spk_alloc, char *buf, int buflen);
-struct hdac_cea_channel_speaker_allocation *snd_hdac_get_ch_alloc_from_ca(int ca);
+const struct hdac_cea_channel_speaker_allocation *
+snd_hdac_get_ch_alloc_from_ca(int ca);
 int snd_hdac_chmap_to_spk_mask(unsigned char c);
 int snd_hdac_spk_to_chmap(int spk);
 int snd_hdac_add_chmap_ctls(struct snd_pcm *pcm, int pcm_idx,
diff --git a/sound/hda/codecs/hdmi/atihdmi.c b/sound/hda/codecs/hdmi/atihdmi.c
index 44366f75de33..9afdbf44b6f0 100644
--- a/sound/hda/codecs/hdmi/atihdmi.c
+++ b/sound/hda/codecs/hdmi/atihdmi.c
@@ -262,7 +262,7 @@ static int atihdmi_paired_swap_fc_lfe(int pos)
 static int atihdmi_paired_chmap_validate(struct hdac_chmap *chmap,
 			int ca, int chs, unsigned char *map)
 {
-	struct hdac_cea_channel_speaker_allocation *cap;
+	const struct hdac_cea_channel_speaker_allocation *cap;
 	int i, j;
 
 	/* check that only channel pairs need to be remapped on old pre-rev3 ATI/AMD */
@@ -377,7 +377,7 @@ static int atihdmi_pin_get_slot_channel(struct hdac_device *hdac,
 
 static int atihdmi_paired_chmap_cea_alloc_validate_get_type(
 		struct hdac_chmap *chmap,
-		struct hdac_cea_channel_speaker_allocation *cap,
+		const struct hdac_cea_channel_speaker_allocation *cap,
 		int channels)
 {
 	int c;
@@ -406,7 +406,7 @@ static int atihdmi_paired_chmap_cea_alloc_validate_get_type(
 }
 
 static void atihdmi_paired_cea_alloc_to_tlv_chmap(struct hdac_chmap *hchmap,
-		struct hdac_cea_channel_speaker_allocation *cap,
+		const struct hdac_cea_channel_speaker_allocation *cap,
 		unsigned int *chmap, int channels)
 {
 	/* produce paired maps for pre-rev3 ATI/AMD codecs */
diff --git a/sound/hda/codecs/hdmi/nvhdmi.c b/sound/hda/codecs/hdmi/nvhdmi.c
index 94671ad24b5e..eaefa016cdec 100644
--- a/sound/hda/codecs/hdmi/nvhdmi.c
+++ b/sound/hda/codecs/hdmi/nvhdmi.c
@@ -24,7 +24,8 @@ enum {
  * - 0x10de0040
  */
 static int nvhdmi_chmap_cea_alloc_validate_get_type(struct hdac_chmap *chmap,
-		struct hdac_cea_channel_speaker_allocation *cap, int channels)
+		const struct hdac_cea_channel_speaker_allocation *cap,
+		int channels)
 {
 	if (cap->ca_index == 0x00 && channels == 2)
 		return SNDRV_CTL_TLVT_CHMAP_FIXED;
diff --git a/sound/hda/codecs/hdmi/tegrahdmi.c b/sound/hda/codecs/hdmi/tegrahdmi.c
index ebb6410a4831..751a50cd4b7d 100644
--- a/sound/hda/codecs/hdmi/tegrahdmi.c
+++ b/sound/hda/codecs/hdmi/tegrahdmi.c
@@ -205,7 +205,8 @@ static int tegra_hdmi_build_pcms(struct hda_codec *codec)
  * - 0x10de0040
  */
 static int nvhdmi_chmap_cea_alloc_validate_get_type(struct hdac_chmap *chmap,
-		struct hdac_cea_channel_speaker_allocation *cap, int channels)
+		const struct hdac_cea_channel_speaker_allocation *cap,
+		int channels)
 {
 	if (cap->ca_index == 0x00 && channels == 2)
 		return SNDRV_CTL_TLVT_CHMAP_FIXED;
diff --git a/sound/hda/core/hdmi_chmap.c b/sound/hda/core/hdmi_chmap.c
index c897fc443467..f76b5dcc6433 100644
--- a/sound/hda/core/hdmi_chmap.c
+++ b/sound/hda/core/hdmi_chmap.c
@@ -341,7 +341,7 @@ static void hdmi_std_setup_channel_mapping(struct hdac_chmap *chmap,
 				       bool non_pcm,
 				       int ca)
 {
-	struct hdac_cea_channel_speaker_allocation *ch_alloc;
+	const struct hdac_cea_channel_speaker_allocation *ch_alloc;
 	int i;
 	int err;
 	int order;
@@ -581,7 +581,8 @@ int snd_hdac_get_active_channels(int ca)
 }
 EXPORT_SYMBOL_GPL(snd_hdac_get_active_channels);
 
-struct hdac_cea_channel_speaker_allocation *snd_hdac_get_ch_alloc_from_ca(int ca)
+const struct hdac_cea_channel_speaker_allocation *
+snd_hdac_get_ch_alloc_from_ca(int ca)
 {
 	return &channel_allocations[get_channel_allocation_order(ca)];
 }
@@ -622,7 +623,8 @@ static int hdmi_chmap_ctl_info(struct snd_kcontrol *kcontrol,
 }
 
 static int hdmi_chmap_cea_alloc_validate_get_type(struct hdac_chmap *chmap,
-		struct hdac_cea_channel_speaker_allocation *cap, int channels)
+		const struct hdac_cea_channel_speaker_allocation *cap,
+		int channels)
 {
 	/* If the speaker allocation matches the channel count, it is OK.*/
 	if (cap->channels != channels)
@@ -633,7 +635,7 @@ static int hdmi_chmap_cea_alloc_validate_get_type(struct hdac_chmap *chmap,
 }
 
 static void hdmi_cea_alloc_to_tlv_chmap(struct hdac_chmap *hchmap,
-		struct hdac_cea_channel_speaker_allocation *cap,
+		const struct hdac_cea_channel_speaker_allocation *cap,
 		unsigned int *chmap, int channels)
 {
 	int count = 0;
@@ -690,7 +692,7 @@ static int hdmi_chmap_ctl_tlv(struct snd_kcontrol *kcontrol, int op_flag,
 
 	for (chs = 2; chs <= max_chs; chs++) {
 		int i;
-		struct hdac_cea_channel_speaker_allocation *cap;
+		const struct hdac_cea_channel_speaker_allocation *cap;
 
 		cap = channel_allocations;
 		for (i = 0; i < ARRAY_SIZE(channel_allocations); i++, cap++) {

-- 
2.54.0