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apps/graphics/ft80x: Fix some circular buffer management logic.

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This commit is contained in:
Gregory Nutt 2018-02-26 08:59:41 -06:00
parent cdfd5afb33
commit d47f474ed6
1 changed files with 158 additions and 31 deletions
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189
graphics/ft80x/ft80x_audio.c
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@ -162,6 +162,82 @@ int ft80x_audio_playfile(int fd, FAR struct ft80x_dlbuffer_s *buffer,
readlen = MAX_DLBUFFER;
}
/* Check size of the buffer we can fit into RAM G */
do
{
/* Get the current playback position */
readptr = 0;
ret = ft80x_getreg32(fd, FT80X_REG_PLAYBACK_READPTR, &readptr);
if (ret < 0)
{
ft80x_err("ERROR: ft80x_getreg32 failed: %d\n", ret);
goto errout_with_fd;
}
/* Check if the readptr is before the current offset. In this
* case, we can use all of the RAM G from the current offset to
* the end of the buffer.
*
* Case 1: readptr <= offset
*
* +--------+-------+-----+
* | | |xxxxx|
* +--------+-------+-----+
* | | | ^ end buffer
* | | ^ offset
* | ^ readptr
* ^ start buffer
*
* NOTE: There is a race condition here: The readptr could
* overtake the offset before we can perform the write.
*/
if (readptr <= offset)
{
freespace = RAMG_MAXOFFSET - offset;
break;
}
/* No, the readptr is after the offset. In this case we can use
* all of the RAM G from the current offset to the readptr.
*
* Case 2: readptr > offset
*
* +--------+-------+-----+
* | |xxxxxxx| |
* +--------+-------+-----+
* | | | ^ end buffer
* | | ^ readptr
* | ^ offset
* ^ start buffer
*/
else
{
freespace = readptr - offset;
}
/* Terminate the poll when all the memory to end of the RAM G
* buffer is available (see the 'break' above), when an optimally
* sized space is available (MAX_DLBUFFER), there is space to
* write all of the 'remaining' file data, or all of the memory is
* free up to the end of the RAM G buffer (actually already
* handled by the above 'break')
*/
}
while (freespace < MAX_DLBUFFER &&
freespace < remaining &&
freespace < (RAMG_MAXOFFSET - offset));
/* Clip to the amount that will fit at the tail of the RAM G buffer */
if (readlen > freespace)
{
readlen = freespace;
}
/* Read the data into the available display list buffer */
nread = read(audiofd, buffer->dlbuffer, readlen);
@ -185,9 +261,18 @@ int ft80x_audio_playfile(int fd, FAR struct ft80x_dlbuffer_s *buffer,
goto errout_with_fd;
}
/* Update pointers and counts */
offset += nread;
remaining -= nread;
/* Wrap the offset back to the beginning of the buffer if necessary */
if (offset >= RAMG_MAXOFFSET)
{
offset = 0;
}
/* If we have started playing the audio file in RAGM_G. NOTE that
* there is a race condition here. If the chunk size is small or if
* the data transfer rate is low, then there may be data under-run
@ -263,49 +348,87 @@ int ft80x_audio_playfile(int fd, FAR struct ft80x_dlbuffer_s *buffer,
started = true;
}
/* Check the freespace if we can fit bull buffer (or the remaining
* buffer) into RAM_G.
*/
do
{
uint32_t inuse;
/* Get the current playback position */
readptr = 0;
ret = ft80x_getreg32(fd, FT80X_REG_PLAYBACK_READPTR, &readptr);
if (ret < 0)
{
ft80x_err("ERROR: ft80x_getreg32 failed: %d\n", ret);
goto errout_with_fd;
}
inuse = (offset - readptr) & RAMG_MAXMASK;
freespace = RAMG_MAXOFFSET - inuse;
}
while (freespace < MAX_DLBUFFER || freespace < remaining);
}
/* Mute the sound clearing by clearing RAM_G after the current offset.
/* Transfer is complete. 'offset' points to the end of the file in RAM G.
* Clear all of the RAM G at the end of the file so that audio is muted
* when the end of file is encountered.
*
* REVISIT: I suspect that this logic is not correct.
* Case 1: readptr <= offset
*
* +--------+-------+-----+
* |00000000| |00000|
* +--------+-------+-----+
* | | | ^ end buffer
* | | ^ offset
* | ^ readptr
* ^ start buffer
*
* Case 2: readptr > offset
*
* +--------+-------+-----+
* | |0000000| |
* +--------+-------+-----+
* | | | ^ end buffer
* | | ^ readptr
* | ^ offset
* ^ start buffer
*/
memset.cmd = FT80X_CMD_MEMSET;
memset.ptr = FT80X_RAM_G + offset;
memset.value = 0;
memset.num = RAMG_MAXOFFSET - offset;
ret = ft80x_coproc_send(fd, (FAR const uint32_t *)&memset, 4);
readptr = 0;
ret = ft80x_getreg32(fd, FT80X_REG_PLAYBACK_READPTR, &readptr);
if (ret < 0)
{
ft80x_err("ERROR: ft80x_ramcmd_append failed: %d\n", ret);
ft80x_err("ERROR: ft80x_getreg32 failed: %d\n", ret);
goto errout_with_fd;
}
/* If the read pointer is already passed over write pointer */
if (readptr <= offset)
{
if (offset < RAMG_MAXOFFSET)
{
memset.ptr = FT80X_RAM_G + offset;
memset.num = RAMG_MAXOFFSET - offset;
ret = ft80x_coproc_send(fd, (FAR const uint32_t *)&memset, 4);
if (ret < 0)
{
ft80x_err("ERROR: ft80x_coproc_send failed: %d\n", ret);
goto errout_with_fd;
}
}
if (readptr > 0)
{
memset.ptr = FT80X_RAM_G;
memset.num = readptr;
ret = ft80x_coproc_send(fd, (FAR const uint32_t *)&memset, 4);
if (ret < 0)
{
ft80x_err("ERROR: ft80x_coproc_send failed: %d\n", ret);
goto errout_with_fd;
}
}
}
else /* if (readptr > offset) */
{
memset.ptr = FT80X_RAM_G + offset;
memset.num = readptr - offset;
ret = ft80x_coproc_send(fd, (FAR const uint32_t *)&memset, 4);
if (ret < 0)
{
ft80x_err("ERROR: ft80x_coproc_send failed: %d\n", ret);
goto errout_with_fd;
}
}
/* Wait until the read pointer wraps back to the beginning of the buffer */
do
{
@ -319,7 +442,11 @@ int ft80x_audio_playfile(int fd, FAR struct ft80x_dlbuffer_s *buffer,
}
while (readptr > offset);
/* Wait till read pointer pass through write pointer */
/* Wait until the read pointer pass through write pointer into the zeroed
* area.
*
* REVISIT: What if the offset is at the very end of the buffer?
*/
do
{