ALSA: pcm: More constifications

Apply const prefix to more possible places: the string tables for PCM
format and co, the table for the PCM type helpers, etc.

Just for minor optimization and no functional changes.

Link: https://lore.kernel.org/r/20200105144823.29547-6-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/pcm.c

@@ -163,7 +163,7 @@ static int snd_pcm_control_ioctl(struct snd_card *card,
 
 #define FORMAT(v) [SNDRV_PCM_FORMAT_##v] = #v
 
-static char *snd_pcm_format_names[] = {
+static const char * const snd_pcm_format_names[] = {
 	FORMAT(S8),
 	FORMAT(U8),
 	FORMAT(S16_LE),
@@ -237,12 +237,12 @@ EXPORT_SYMBOL_GPL(snd_pcm_format_name);
 #define START(v) [SNDRV_PCM_START_##v] = #v
 #define SUBFORMAT(v) [SNDRV_PCM_SUBFORMAT_##v] = #v 
 
-static char *snd_pcm_stream_names[] = {
+static const char * const snd_pcm_stream_names[] = {
 	STREAM(PLAYBACK),
 	STREAM(CAPTURE),
 };
 
-static char *snd_pcm_state_names[] = {
+static const char * const snd_pcm_state_names[] = {
 	STATE(OPEN),
 	STATE(SETUP),
 	STATE(PREPARED),
@@ -253,7 +253,7 @@ static char *snd_pcm_state_names[] = {
 	STATE(SUSPENDED),
 };
 
-static char *snd_pcm_access_names[] = {
+static const char * const snd_pcm_access_names[] = {
 	ACCESS(MMAP_INTERLEAVED), 
 	ACCESS(MMAP_NONINTERLEAVED),
 	ACCESS(MMAP_COMPLEX),
@@ -261,11 +261,11 @@ static char *snd_pcm_access_names[] = {
 	ACCESS(RW_NONINTERLEAVED),
 };
 
-static char *snd_pcm_subformat_names[] = {
+static const char * const snd_pcm_subformat_names[] = {
 	SUBFORMAT(STD), 
 };
 
-static char *snd_pcm_tstamp_mode_names[] = {
+static const char * const snd_pcm_tstamp_mode_names[] = {
 	TSTAMP(NONE),
 	TSTAMP(ENABLE),
 };

sound/core/pcm_lib.c

@@ -1452,7 +1452,7 @@ EXPORT_SYMBOL(snd_pcm_hw_constraint_step);
 
 static int snd_pcm_hw_rule_pow2(struct snd_pcm_hw_params *params, struct snd_pcm_hw_rule *rule)
 {
-	static unsigned int pow2_sizes[] = {
+	static const unsigned int pow2_sizes[] = {
 		1<<0, 1<<1, 1<<2, 1<<3, 1<<4, 1<<5, 1<<6, 1<<7,
 		1<<8, 1<<9, 1<<10, 1<<11, 1<<12, 1<<13, 1<<14, 1<<15,
 		1<<16, 1<<17, 1<<18, 1<<19, 1<<20, 1<<21, 1<<22, 1<<23,

sound/core/pcm_misc.c

@@ -42,7 +42,7 @@ struct pcm_format_data {
 /* we do lots of calculations on snd_pcm_format_t; shut up sparse */
 #define INT	__force int
 
-static struct pcm_format_data pcm_formats[(INT)SNDRV_PCM_FORMAT_LAST+1] = {
+static const struct pcm_format_data pcm_formats[(INT)SNDRV_PCM_FORMAT_LAST+1] = {
 	[SNDRV_PCM_FORMAT_S8] = {
 		.width = 8, .phys = 8, .le = -1, .signd = 1,
 		.silence = {},
@@ -415,7 +415,8 @@ EXPORT_SYMBOL(snd_pcm_format_silence_64);
 int snd_pcm_format_set_silence(snd_pcm_format_t format, void *data, unsigned int samples)
 {
 	int width;
-	unsigned char *dst, *pat;
+	unsigned char *dst;
+	const unsigned char *pat;
 
 	if ((INT)format < 0 || (INT)format > (INT)SNDRV_PCM_FORMAT_LAST)
 		return -EINVAL;