ASoC: sh: fsi: tidyup unclear variable naming

Some variables on this driver were a unclear naming,
and were different unit (byte, frame, sample).
And some functions had wrong name
(ex. it returned "sample width" but name was "fsi_get_frame_width").
This patch tidy-up this issue, and the minimum unit become "sample".
Special thanks to Takashi YOSHII.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 100 insertions, 82 deletions

diff --git a/sound/soc/sh/fsi.c b/sound/soc/sh/fsi.c
index 643d256e13c8..fec1a7dcf90b 100644
--- a/sound/soc/sh/fsi.c
+++ b/sound/soc/sh/fsi.c
@@ -118,10 +118,38 @@ typedef int (*set_rate_func)(struct device *dev, int is_porta, int rate, int ena
 /*
  * FSI driver use below type name for variable
  *
- * xxx_len      : data length
- * xxx_width    : data width
- * xxx_offset   : data offset
  * xxx_num      : number of data
+ * xxx_pos      : position of data
+ * xxx_capa     : capacity of data
+ */
+
+/*
+ *      period/frame/sample image
+ *
+ * ex) PCM (2ch)
+ *
+ * period pos                                      period pos
+ *   [n]                                             [n + 1]
+ *   |<-------------------- period--------------------->|
+ * ==|============================================ ... =|==
+ *   |                                                  |
+ *   ||<-----  frame ----->|<------ frame ----->|  ...  |
+ *   |+--------------------+--------------------+- ...  |
+ *   ||[ sample ][ sample ]|[ sample ][ sample ]|  ...  |
+ *   |+--------------------+--------------------+- ...  |
+ * ==|============================================ ... =|==
+ */
+
+/*
+ *      FSI FIFO image
+ *
+ *      |            |
+ *      |            |
+ *      | [ sample ] |
+ *      | [ sample ] |
+ *      | [ sample ] |
+ *      | [ sample ] |
+ *              --> go to codecs
  */
 
 /*
@@ -131,12 +159,11 @@ typedef int (*set_rate_func)(struct device *dev, int is_porta, int rate, int ena
 struct fsi_stream {
         struct snd_pcm_substream *substream;
 
-        int fifo_max_num;
-
-        int buff_offset;
-        int buff_len;
-        int period_len;
-        int period_num;
+        int fifo_sample_capa;   /* sample capacity of FSI FIFO */
+        int buff_sample_capa;   /* sample capacity of ALSA buffer */
+        int buff_sample_pos;    /* sample position of ALSA buffer */
+        int period_samples;     /* sample number / 1 period */
+        int period_pos;         /* current period position */
 
         int uerr_num;
         int oerr_num;
@@ -342,6 +369,16 @@ static u32 fsi_get_port_shift(struct fsi_priv *fsi, int is_play)
         return shift;
 }
 
+static int fsi_frame2sample(struct fsi_priv *fsi, int frames)
+{
+        return frames * fsi->chan_num;
+}
+
+static int fsi_sample2frame(struct fsi_priv *fsi, int samples)
+{
+        return samples / fsi->chan_num;
+}
+
 static void fsi_stream_push(struct fsi_priv *fsi,
                             int is_play,
                             struct snd_pcm_substream *substream)
@@ -350,10 +387,10 @@ static void fsi_stream_push(struct fsi_priv *fsi,
         struct snd_pcm_runtime *runtime = substream->runtime;
 
         io->substream   = substream;
-        io->buff_len    = frames_to_bytes(runtime, runtime->buffer_size);
-        io->buff_offset = 0;
-        io->period_len  = frames_to_bytes(runtime, runtime->period_size);
-        io->period_num  = 0;
+        io->buff_sample_capa    = fsi_frame2sample(fsi, runtime->buffer_size);
+        io->buff_sample_pos     = 0;
+        io->period_samples      = fsi_frame2sample(fsi, runtime->period_size);
+        io->period_pos          = 0;
         io->oerr_num    = -1; /* ignore 1st err */
         io->uerr_num    = -1; /* ignore 1st err */
 }
@@ -371,47 +408,26 @@ static void fsi_stream_pop(struct fsi_priv *fsi, int is_play)
                 dev_err(dai->dev, "under_run = %d\n", io->uerr_num);
 
         io->substream   = NULL;
-        io->buff_len    = 0;
-        io->buff_offset = 0;
-        io->period_len  = 0;
-        io->period_num  = 0;
+        io->buff_sample_capa    = 0;
+        io->buff_sample_pos     = 0;
+        io->period_samples      = 0;
+        io->period_pos          = 0;
         io->oerr_num    = 0;
         io->uerr_num    = 0;
 }
 
-static int fsi_get_fifo_data_num(struct fsi_priv *fsi, int is_play)
+static int fsi_get_current_fifo_samples(struct fsi_priv *fsi, int is_play)
 {
         u32 status;
-        int data_num;
+        int frames;
 
         status = is_play ?
                 fsi_reg_read(fsi, DOFF_ST) :
                 fsi_reg_read(fsi, DIFF_ST);
 
-        data_num = 0x1ff & (status >> 8);
-        data_num *= fsi->chan_num;
-
-        return data_num;
-}
-
-static int fsi_len2num(int len, int width)
-{
-        return len / width;
-}
+        frames = 0x1ff & (status >> 8);
 
-#define fsi_num2offset(a, b) fsi_num2len(a, b)
-static int fsi_num2len(int num, int width)
-{
-        return num * width;
-}
-
-static int fsi_get_frame_width(struct fsi_priv *fsi, int is_play)
-{
-        struct fsi_stream *io = fsi_get_stream(fsi, is_play);
-        struct snd_pcm_substream *substream = io->substream;
-        struct snd_pcm_runtime *runtime = substream->runtime;
-
-        return frames_to_bytes(runtime, 1) / fsi->chan_num;
+        return fsi_frame2sample(fsi, frames);
 }
 
 static void fsi_count_fifo_err(struct fsi_priv *fsi)
@@ -443,8 +459,10 @@ static u8 *fsi_dma_get_area(struct fsi_priv *fsi, int stream)
 {
         int is_play = fsi_stream_is_play(stream);
         struct fsi_stream *io = fsi_get_stream(fsi, is_play);
+        struct snd_pcm_runtime *runtime = io->substream->runtime;
 
-        return io->substream->runtime->dma_area + io->buff_offset;
+        return runtime->dma_area +
+                samples_to_bytes(runtime, io->buff_sample_pos);
 }
 
 static void fsi_dma_soft_push16(struct fsi_priv *fsi, int num)
@@ -683,13 +701,14 @@ static void fsi_fifo_init(struct fsi_priv *fsi,
         struct fsi_master *master = fsi_get_master(fsi);
         struct fsi_stream *io = fsi_get_stream(fsi, is_play);
         u32 shift, i;
+        int frame_capa;
 
         /* get on-chip RAM capacity */
         shift = fsi_master_read(master, FIFO_SZ);
         shift >>= fsi_get_port_shift(fsi, is_play);
         shift &= FIFO_SZ_MASK;
-        io->fifo_max_num = 256 << shift;
-        dev_dbg(dai->dev, "fifo = %d words\n", io->fifo_max_num);
+        frame_capa = 256 << shift;
+        dev_dbg(dai->dev, "fifo = %d words\n", frame_capa);
 
         /*
          * The maximum number of sample data varies depending
@@ -711,9 +730,11 @@ static void fsi_fifo_init(struct fsi_priv *fsi,
          * 8 channels:  32 ( 32 x 8 = 256)
          */
         for (i = 1; i < fsi->chan_num; i <<= 1)
-                io->fifo_max_num >>= 1;
+                frame_capa >>= 1;
         dev_dbg(dai->dev, "%d channel %d store\n",
-                fsi->chan_num, io->fifo_max_num);
+                fsi->chan_num, frame_capa);
+
+        io->fifo_sample_capa = fsi_frame2sample(fsi, frame_capa);
 
         /*
          * set interrupt generation factor
@@ -734,10 +755,10 @@ static int fsi_fifo_data_ctrl(struct fsi_priv *fsi, int stream)
         struct snd_pcm_substream *substream = NULL;
         int is_play = fsi_stream_is_play(stream);
         struct fsi_stream *io = fsi_get_stream(fsi, is_play);
-        int data_residue_num;
-        int data_num;
-        int data_num_max;
-        int ch_width;
+        int sample_residues;
+        int sample_width;
+        int samples;
+        int samples_max;
         int over_period;
         void (*fn)(struct fsi_priv *fsi, int size);
 
@@ -753,36 +774,35 @@ static int fsi_fifo_data_ctrl(struct fsi_priv *fsi, int stream)
         /* FSI FIFO has limit.
          * So, this driver can not send periods data at a time
          */
-        if (io->buff_offset >=
-            fsi_num2offset(io->period_num + 1, io->period_len)) {
+        if (io->buff_sample_pos >=
+            io->period_samples * (io->period_pos + 1)) {
 
                 over_period = 1;
-                io->period_num = (io->period_num + 1) % runtime->periods;
+                io->period_pos = (io->period_pos + 1) % runtime->periods;
 
-                if (0 == io->period_num)
-                        io->buff_offset = 0;
+                if (0 == io->period_pos)
+                        io->buff_sample_pos = 0;
         }
 
-        /* get 1 channel data width */
-        ch_width = fsi_get_frame_width(fsi, is_play);
+        /* get 1 sample data width */
+        sample_width = samples_to_bytes(runtime, 1);
 
-        /* get residue data number of alsa */
-        data_residue_num = fsi_len2num(io->buff_len - io->buff_offset,
-                                       ch_width);
+        /* get number of residue samples */
+        sample_residues = io->buff_sample_capa - io->buff_sample_pos;
 
         if (is_play) {
                 /*
                  * for play-back
                  *
-                 * data_num_max : number of FSI fifo free space
-                 * data_num     : number of ALSA residue data
+                 * samples_max  : number of FSI fifo free samples space
+                 * samples      : number of ALSA residue samples
                  */
-                data_num_max  = io->fifo_max_num * fsi->chan_num;
-                data_num_max -= fsi_get_fifo_data_num(fsi, is_play);
+                samples_max  = io->fifo_sample_capa;
+                samples_max -= fsi_get_current_fifo_samples(fsi, is_play);
 
-                data_num = data_residue_num;
+                samples = sample_residues;
 
-                switch (ch_width) {
+                switch (sample_width) {
                 case 2:
                         fn = fsi_dma_soft_push16;
                         break;
@@ -796,13 +816,13 @@ static int fsi_fifo_data_ctrl(struct fsi_priv *fsi, int stream)
                 /*
                  * for capture
                  *
-                 * data_num_max : number of ALSA free space
-                 * data_num     : number of data in FSI fifo
+                 * samples_max  : number of ALSA free samples space
+                 * samples      : number of samples in FSI fifo
                  */
-                data_num_max = data_residue_num;
-                data_num     = fsi_get_fifo_data_num(fsi, is_play);
+                samples_max = sample_residues;
+                samples     = fsi_get_current_fifo_samples(fsi, is_play);
 
-                switch (ch_width) {
+                switch (sample_width) {
                 case 2:
                         fn = fsi_dma_soft_pop16;
                         break;
@@ -814,12 +834,12 @@ static int fsi_fifo_data_ctrl(struct fsi_priv *fsi, int stream)
                 }
         }
 
-        data_num = min(data_num, data_num_max);
+        samples = min(samples, samples_max);
 
-        fn(fsi, data_num);
+        fn(fsi, samples);
 
-        /* update buff_offset */
-        io->buff_offset += fsi_num2offset(data_num, ch_width);
+        /* update buff_sample_pos */
+        io->buff_sample_pos += samples;
 
         if (over_period)
                 snd_pcm_period_elapsed(substream);
@@ -1107,16 +1127,14 @@ static int fsi_hw_free(struct snd_pcm_substream *substream)
 
 static snd_pcm_uframes_t fsi_pointer(struct snd_pcm_substream *substream)
 {
-        struct snd_pcm_runtime *runtime = substream->runtime;
         struct fsi_priv *fsi = fsi_get_priv(substream);
         struct fsi_stream *io = fsi_get_stream(fsi, fsi_is_play(substream));
-        long location;
+        int samples_pos = io->buff_sample_pos - 1;
 
-        location = (io->buff_offset - 1);
-        if (location < 0)
-                location = 0;
+        if (samples_pos < 0)
+                samples_pos = 0;
 
-        return bytes_to_frames(runtime, location);
+        return fsi_sample2frame(fsi, samples_pos);
 }
 
 static struct snd_pcm_ops fsi_pcm_ops = {