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2010-06-22 Arnout Vandecappelle <arnout@mind.be>

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PR 1580/misc
	* libchip/i2c/spi-sd-card.c: Use bigger chunks and yield processor
	while waiting for read data.
This commit is contained in:
Sebastian Huber
2010-06-22 11:36:14 +00:00
parent 5e649e5186
commit 0596902ec8
2 changed files with 38 additions and 24 deletions
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6
c/src/ChangeLog
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@@ -1,3 +1,9 @@
2010-06-22 Arnout Vandecappelle <arnout@mind.be>
PR 1580/misc
* libchip/i2c/spi-sd-card.c: Use bigger chunks and yield processor
while waiting for read data.
2010-06-22 Arnout Vandecappelle <arnout@mind.be>
PR 1579/misc

56
c/src/libchip/i2c/spi-sd-card.c
View File

@@ -374,7 +374,7 @@ static int sd_card_wait( sd_card_driver_entry *e)
FIXME should actually look at R2W_FACTOR for non-HC cards. */
int retries = e->n_ac_max * 25 / 10;
/* n_ac_max/100 is supposed to be the average waiting time. To
approximate this, we start with waiting n_ac_max/250 and
approximate this, we start with waiting n_ac_max/150 and
gradually increase the waiting time. */
int wait_time_bytes = (retries + 149) / 150;
while (e->busy) {
@@ -530,57 +530,65 @@ static int sd_card_read( sd_card_driver_entry *e, uint8_t start_token, uint8_t *
{
int rv = 0;
/* Access time idle tokens */
uint32_t n_ac = 1;
/* Discard command response */
int r = e->response_index + 1;
/* Minimum token number before data start */
int next_response_size = 2;
/* Standard response size */
int response_size = SD_CARD_COMMAND_SIZE;
/* Where the response is stored */
uint8_t *response = e->response;
/* Data input index */
int i = 0;
/* CRC check of data */
uint16_t crc16;
/* Maximum number of tokens to read. */
int retries = e->n_ac_max;
SD_CARD_INVALIDATE_RESPONSE_INDEX( e);
while (true) {
RTEMS_DEBUG_PRINT( "Search from %u to %u\n", r, response_size - 1);
/* Search the data start token in in current response buffer */
retries -= (response_size - r);
while (r < response_size) {
RTEMS_DEBUG_PRINT( "Token [%02u]: 0x%02x\n", r, e->response [r]);
if (n_ac > e->n_ac_max) {
RTEMS_SYSLOG_ERROR( "Timeout\n");
return -RTEMS_IO_ERROR;
} else if (e->response [r] == start_token) {
RTEMS_DEBUG_PRINT( "Token [%02u]: 0x%02x\n", r, response [r]);
if (response [r] == start_token) {
/* Discard data start token */
++r;
goto sd_card_read_start;
} else if (SD_CARD_IS_DATA_ERROR( e->response [r])) {
RTEMS_SYSLOG_ERROR( "Data error token [%02i]: 0x%02" PRIx8 "\n", r, e->response [r]);
} else if (SD_CARD_IS_DATA_ERROR( response [r])) {
RTEMS_SYSLOG_ERROR( "Data error token [%02i]: 0x%02" PRIx8 "\n", r, response [r]);
return -RTEMS_IO_ERROR;
} else if (e->response [r] != SD_CARD_IDLE_TOKEN) {
RTEMS_SYSLOG_ERROR( "Unexpected token [%02i]: 0x%02" PRIx8 "\n", r, e->response [r]);
} else if (response [r] != SD_CARD_IDLE_TOKEN) {
RTEMS_SYSLOG_ERROR( "Unexpected token [%02i]: 0x%02" PRIx8 "\n", r, response [r]);
return -RTEMS_IO_ERROR;
}
++n_ac;
++r;
}
/* Query more */
rv = sd_card_query( e, e->response, next_response_size);
RTEMS_CHECK_RV( rv, "Query data start token");
if (retries <= 0) {
RTEMS_SYSLOG_ERROR( "Timeout\n");
return -RTEMS_IO_ERROR;
}
/* Set standard query size */
response_size = next_response_size;
next_response_size = SD_CARD_COMMAND_SIZE;
if (e->schedule_if_busy)
rtems_task_wake_after( RTEMS_YIELD_PROCESSOR);
/* Query more. We typically have to wait between 10 and 100
bytes. To reduce overhead, read the response in chunks of
50 bytes - this doesn't introduce too much copy overhead
but does allow SPI DMA transfers to work efficiently. */
response = in;
response_size = 50;
if (response_size > n)
response_size = n;
rv = sd_card_query( e, response, response_size);
RTEMS_CHECK_RV( rv, "Query data start token");
/* Reset start position */
r = 0;
@@ -590,7 +598,7 @@ sd_card_read_start:
/* Read data */
while (r < response_size && i < n) {
in [i++] = e->response [r++];
in [i++] = response [r++];
}
/* Read more data? */