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Replaced busy wait while loop with timers

pull/7774/head
Deepika 2017-06-23 15:37:26 -05:00
parent df8e085ee3
commit 25652a50cd
2 changed files with 76 additions and 37 deletions
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91
features/filesystem/sd/SDBlockDevice.cpp
View File

@ -147,9 +147,9 @@
#include "SDBlockDevice.h"
#include "mbed_debug.h"
#define SD_COMMAND_TIMEOUT 5000 /*!< Number of times to query card for correct result */
#define SD_COMMAND_TIMEOUT 5000 /*!< Timeout in ms for response */
#define SD_CMD0_GO_IDLE_STATE_RETRIES 5 /*!< Number of retries for sending CMDO */
#define SD_DBG 1
#define SD_DBG 0 /*!< 1 - Enable debugging */
#define SD_BLOCK_DEVICE_ERROR_WOULD_BLOCK -5001 /*!< operation would block */
#define SD_BLOCK_DEVICE_ERROR_UNSUPPORTED -5002 /*!< unsupported operation */
@ -299,13 +299,12 @@ int SDBlockDevice::_initialise_card()
* "0" indicates completion of initialization. The host repeatedly issues ACMD41 until
* this bit is set to "0".
*/
for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
_cmd(CMD55_APP_CMD, 0);
status = _cmd(ACMD41_SD_SEND_OP_COND, arg, &response);
if (0x0 == (R1_IDLE_STATE & response))
break;
wait_ms(5);
}
_spi_timer.start();
do {
status = _cmd(ACMD41_SD_SEND_OP_COND, arg, 1, &response);
} while ((response & R1_IDLE_STATE) && (_spi_timer.read_ms() < SD_COMMAND_TIMEOUT));
_spi_timer.stop();
// Initialization complete: ACMD41 successful
if ((BD_ERROR_OK != status) || (0x00 != response)) {
_card_type = CARD_UNKNOWN;
@ -413,24 +412,27 @@ int SDBlockDevice::program(const void *b, bd_addr_t addr, bd_size_t size)
buffer += _block_size;
}while (--blockCnt); // Receive all blocks of data
if (SPI_START_BLK_MUL_WRITE == token) {
/* In a Multiple Block write operation, the stop transmission will be done by
* sending 'Stop Tran' token instead of 'Start Block' token at the beginning
* of the next block
*/
if(SPI_START_BLK_MUL_WRITE == token) {
_select();
_spi.write(SPI_STOP_TRAN);
_deselect();
}
// Wait for last block to be written
_wait_ready(SD_COMMAND_TIMEOUT);
// SEND_NUM_WR_BLOCKS (ACMD22) in order to get the number of well written write blocks.
_cmd(CMD55_APP_CMD, 0);
if(BD_ERROR_OK == _cmd(ACMD22_SEND_NUM_WR_BLOCKS, 0)) {
if (BD_ERROR_OK == _cmd(ACMD22_SEND_NUM_WR_BLOCKS, 0, 1)) {
uint8_t wr_blocks[4];
if(BD_ERROR_OK == _read(wr_blocks, 4)) {
debug_if(SD_DBG, "Blocks Written without errors: 0x%x\n",
if (BD_ERROR_OK == _read(wr_blocks, 4)) {
debug_if(_dbg, "Blocks Written without errors: 0x%x\n",
((wr_blocks[0] << 24) | (wr_blocks[1] << 16) | (wr_blocks[2] << 0) | wr_blocks[3]));
}
}
}
_lock.unlock();
return status;
}
@ -558,8 +560,8 @@ uint8_t SDBlockDevice::_cmd_spi(SDBlockDevice::cmdSupported cmd, uint32_t arg) {
_spi.write(0xFF);
}
// wait for the response (response[7] == 0)
for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
// Loop for response: Response is sent back within command response time (NCR), 0 to 8 bytes for SDC
for (int i = 0; i < 0x10; i++) {
response = _spi.write(0xFF);
// Got the response
if (!(response & R1_RESPONSE_RECV)) {
@ -569,11 +571,18 @@ uint8_t SDBlockDevice::_cmd_spi(SDBlockDevice::cmdSupported cmd, uint32_t arg) {
return response;
}
int SDBlockDevice::_cmd(SDBlockDevice::cmdSupported cmd, uint32_t arg, uint32_t *resp) {
int SDBlockDevice::_cmd(SDBlockDevice::cmdSupported cmd, uint32_t arg, bool isAcmd, uint32_t *resp) {
int32_t status = BD_ERROR_OK;
uint32_t response;
// Select card
// Select card and wait for card to be ready before sending next command
_select();
_wait_ready();
// Send CMD55 for APP command first
if (isAcmd) {
_cmd_spi(CMD55_APP_CMD, 0x0);
}
// Send command over SPI interface
response = _cmd_spi(cmd, arg);
@ -624,7 +633,8 @@ int SDBlockDevice::_cmd(SDBlockDevice::cmdSupported cmd, uint32_t arg, uint32_t
break;
case CMD12_STOP_TRANSMISSION: // Response R1b
case CMD38_ERASE: // TODO:
case CMD38_ERASE:
_wait_ready(SD_COMMAND_TIMEOUT);
break;
case ACMD13_SD_STATUS: // Response R2
@ -653,9 +663,9 @@ int SDBlockDevice::_cmd8() {
arg |= (0x1 << 8); // 2.7-3.6V // [11:8]supply voltage(VHS)
status = _cmd(CMD8_SEND_IF_COND, arg, &response);
status = _cmd(CMD8_SEND_IF_COND, arg, 0x0, &response);
// Verify voltage and pattern for V2 version of card
if( (BD_ERROR_OK == status) && (SDCARD_V2 == _card_type)) {
if ((BD_ERROR_OK == status) && (SDCARD_V2 == _card_type)) {
// If check pattern is not matched, CMD8 communication is not valid
if((response & 0xFFF) != arg)
{
@ -676,7 +686,7 @@ uint32_t SDBlockDevice::_go_idle_state() {
* not be interpreted as a command and get lost. For some cards retrying
* the command overcomes this situation. */
for (int i = 0; i < SD_CMD0_GO_IDLE_STATE_RETRIES; i++) {
_cmd(CMD0_GO_IDLE_STATE, 0, &response);
_cmd(CMD0_GO_IDLE_STATE, 0x0, 0x0, &response);
if (R1_IDLE_STATE == response)
break;
wait_ms(1);
@ -711,6 +721,11 @@ int SDBlockDevice::_write(const uint8_t*buffer, uint8_t token, uint32_t length)
// Select card
_select();
/* If previous write is in progress, the card will drive DO low again when reselected.
* Therefore a preceding busy check, check if card is busy prior to each command and
* data packet, instead of post wait, can eliminate busy wait time */
_wait_ready(SD_COMMAND_TIMEOUT);
// indicate start of block
_spi.write(token);
@ -729,8 +744,6 @@ int SDBlockDevice::_write(const uint8_t*buffer, uint8_t token, uint32_t length)
return SD_BLOCK_DEVICE_ERROR_WRITE;
}
// wait for write to finish
while (_spi.write(0xFF) == 0);
_deselect();
return 0;
@ -799,6 +812,30 @@ uint32_t SDBlockDevice::_sd_sectors() {
return blocks;
}
// SPI function to wait till chip is ready
// The host controller should wait for end of the process until DO goes high (a 0xFF is received).
void SDBlockDevice::_wait_ready(uint16_t ms) {
uint8_t response;
_spi_timer.reset();
_spi_timer.start();
do {
response = _spi.write(0xFF);
if (response == 0xFF) {
break;
}
} while (_spi_timer.read_ms() < ms);
_spi_timer.stop();
return;
}
// SPI function to wait for count
void SDBlockDevice::_spi_wait(uint8_t count)
{
for (uint8_t i = 0; i < count; ++i) {
_spi.write(0xFF);
}
}
void SDBlockDevice::_spi_init() {
_spi.lock();
// Set to SCK for initialization, and clock card with cs = 1
@ -806,9 +843,7 @@ void SDBlockDevice::_spi_init() {
_spi.format(8, 0);
// Initial 74 cycles required for few cards, before selecting SPI mode
_cs = 1;
for (int i = 0; i < 10; i++) {
_spi.write(0xFF);
}
_spi_wait(10);
_spi.unlock();
}

6
features/filesystem/sd/SDBlockDevice.h
View File

@ -169,7 +169,7 @@ private:
};
uint8_t _card_type;
int _cmd(SDBlockDevice::cmdSupported cmd, uint32_t arg, uint32_t *resp=NULL);
int _cmd(SDBlockDevice::cmdSupported cmd, uint32_t arg, bool isAcmd=0, uint32_t *resp=NULL);
int _cmd8();
/* Move the SDCard into the SPI Mode idle state
@ -193,11 +193,15 @@ private:
uint32_t _sectors;
/* SPI functions */
Timer _spi_timer; /**< Timer Class object used for busy wait */
uint32_t _init_sck; /**< Intial SPI frequency */
uint32_t _transfer_sck; /**< SPI frequency during data transfer/after initialization */
SPI _spi;
void _spi_init();
uint8_t _cmd_spi(SDBlockDevice::cmdSupported cmd, uint32_t arg);
void _spi_wait(uint8_t count);
void _wait_ready(uint16_t ms=200); /**< 200ms default wait for card to be ready */
/* Chip Select and SPI mode select */
DigitalOut _cs;