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Fix to SST25 driver to permit faster write modes. From David Sidrane

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This commit is contained in:
Gregory Nutt 2013-11-02 08:27:13 -06:00
parent f3313a0f51
commit a2b6d12271
6 changed files with 58 additions and 51 deletions
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10
ChangeLog
View File

@ -5945,4 +5945,12 @@
from David Sidrane plugs the hole for now (2013-11-1).
* drivers/mtd/mtd_config.c: Reduce configuration header size. From
Ken Pettit (2013-11-1).
* drivers/mtd/sst25.c: Improved write performance by fixing a bug
that prevented operation in the faster write mode. The code did
not wait on the last write complete before issuing the WRDI The
loop in general failed to wait on the fist 2 bytes after the
SST25_AAI if the next 2 were FF FF, then it would reissue the
address but not cancel the write. Reorganized to always wait for
completion after and address with data write and on any data
write so that the device is complete before WRDI is sent. From
David Sidrane (2013-11-2).

2
configs/spark/composite/defconfig
View File

@ -465,7 +465,7 @@ CONFIG_SST25_SPIMODE=0
CONFIG_SST25_SPIFREQUENCY=80000000
# CONFIG_SST25_READONLY is not set
CONFIG_SST25_SECTOR512=y
CONFIG_SST25_SLOWWRITE=y
# CONFIG_SST25_SLOWWRITE is not set
# CONFIG_SST25_SLOWREAD is not set
# CONFIG_MTD_SST39FV is not set
# CONFIG_MTD_W25 is not set

2
configs/spark/nsh/defconfig
View File

@ -439,7 +439,7 @@ CONFIG_SST25_SPIMODE=0
CONFIG_SST25_SPIFREQUENCY=80000000
# CONFIG_SST25_READONLY is not set
CONFIG_SST25_SECTOR512=y
CONFIG_SST25_SLOWWRITE=y
# CONFIG_SST25_SLOWWRITE is not set
# CONFIG_SST25_SLOWREAD is not set
# CONFIG_MTD_SST39FV is not set
# CONFIG_MTD_W25 is not set

2
configs/spark/usbmsc/defconfig
View File

@ -439,7 +439,7 @@ CONFIG_SST25_SPIMODE=0
CONFIG_SST25_SPIFREQUENCY=80000000
# CONFIG_SST25_READONLY is not set
CONFIG_SST25_SECTOR512=y
CONFIG_SST25_SLOWWRITE=y
# CONFIG_SST25_SLOWWRITE is not set
# CONFIG_SST25_SLOWREAD is not set
# CONFIG_MTD_SST39FV is not set
# CONFIG_MTD_W25 is not set

8
drivers/mtd/Kconfig
View File

@ -259,7 +259,13 @@ config SST25_SECTOR512
config SST25_SLOWWRITE
bool
default y
default n
---help---
There used to be a bug in the current code when using the higher speed AAI
write sequence. The nature of the bug is that the WRDI instruction is not
working. At the end of the AAI sequence, the status register continues to
report that the SST25 is write enabled (WEL bit) and in AAI mode (AAI
bit). This has been fixed by David Sidrane!
config SST25_SLOWREAD
bool

85
drivers/mtd/sst25.c
View File

@ -82,17 +82,6 @@
# define CONFIG_SST25_SPIFREQUENCY 20000000
#endif
/* There is a bug in the current code when using the higher speed AAI write sequence.
* The nature of the bug is that the WRDI instruction is not working. At the end
* of the AAI sequence, the status register continues to report that the SST25 is
* write enabled (WEL bit) and in AAI mode (AAI bit). This *must* be fixed in any
* production code if you want to have proper write performance.
*/
#warning "REVISIT"
#undef CONFIG_SST25_SLOWWRITE
#define CONFIG_SST25_SLOWWRITE 1
/* SST25 Instructions ***************************************************************/
/* Command Value Description Addr Data */
/* Dummy */
@ -225,9 +214,10 @@ static void sst25_lock(FAR struct spi_dev_s *dev);
static inline void sst25_unlock(FAR struct spi_dev_s *dev);
static inline int sst25_readid(FAR struct sst25_dev_s *priv);
#ifndef CONFIG_SST25_READONLY
static void sst25_unprotect(FAR struct spi_dev_s *dev);
static void sst25_unprotect(FAR struct sst25_dev_s *priv);
#endif
static uint8_t sst25_waitwritecomplete(FAR struct sst25_dev_s *priv);
static inline void sst25_cmd(struct sst25_dev_s *priv, uint8_t cmd);
static inline void sst25_wren(FAR struct sst25_dev_s *priv);
#if !defined(CONFIG_SST25_SLOWWRITE) && !defined(CONFIG_SST25_READONLY)
static inline void sst25_wrdi(FAR struct sst25_dev_s *priv);
@ -377,30 +367,23 @@ static inline int sst25_readid(struct sst25_dev_s *priv)
************************************************************************************/
#ifndef CONFIG_SST25_READONLY
static void sst25_unprotect(FAR struct spi_dev_s *dev)
static void sst25_unprotect(struct sst25_dev_s *priv)
{
/* Select this FLASH part */
SPI_SELECT(dev, SPIDEV_FLASH, true);
/* Send "Write enable status (EWSR)" */
SPI_SEND(dev, SST25_EWSR);
sst25_cmd(priv, SST25_EWSR);
/* Re-select this FLASH part (This might not be necessary... but is it shown in
* the timing diagrams)
*/
/* Send "Write enable status (WRSR)" */
SPI_SELECT(dev, SPIDEV_FLASH, false);
SPI_SELECT(dev, SPIDEV_FLASH, true);
SPI_SELECT(priv->dev, SPIDEV_FLASH, true);
/* Send "Write enable status (EWSR)" */
SPI_SEND(priv->dev, SST25_WRSR);
SPI_SEND(dev, SST25_WRSR);
/* Followed by the new status value */
/* Following by the new status value */
SPI_SEND(priv->dev, 0);
SPI_SEND(dev, 0);
SPI_SELECT(priv->dev, SPIDEV_FLASH, false);
}
#endif
@ -481,41 +464,45 @@ static uint8_t sst25_waitwritecomplete(struct sst25_dev_s *priv)
}
/************************************************************************************
* Name: sst25_wren
* Name: sst25_cmd
************************************************************************************/
static inline void sst25_wren(struct sst25_dev_s *priv)
static inline void sst25_cmd(struct sst25_dev_s *priv, uint8_t cmd)
{
/* Select this FLASH part */
SPI_SELECT(priv->dev, SPIDEV_FLASH, true);
/* Send "Write Enable (WREN)" command */
/* Send command */
(void)SPI_SEND(priv->dev, cmd);
(void)SPI_SEND(priv->dev, SST25_WREN);
/* Deselect the FLASH */
SPI_SELECT(priv->dev, SPIDEV_FLASH, false);
}
/************************************************************************************
* Name: sst25_wren
************************************************************************************/
static inline void sst25_wren(struct sst25_dev_s *priv)
{
/* Send "Write Enable (WREN)" command */
sst25_cmd(priv, SST25_WREN);
}
/************************************************************************************
* Name: sst25_wrdi
************************************************************************************/
#if !defined(CONFIG_SST25_SLOWWRITE) && !defined(CONFIG_SST25_READONLY)
static inline void sst25_wrdi(struct sst25_dev_s *priv)
{
/* Select this FLASH part */
SPI_SELECT(priv->dev, SPIDEV_FLASH, true);
/* Send "Write Disable (WRDI)" command */
(void)SPI_SEND(priv->dev, SST25_WRDI);
/* Deselect the FLASH */
SPI_SELECT(priv->dev, SPIDEV_FLASH, false);
sst25_cmd(priv, SST25_WRDI);
}
#endif
@ -770,6 +757,11 @@ static void sst25_wordwrite(struct sst25_dev_s *priv, FAR const uint8_t *buffer,
SPI_SELECT(priv->dev, SPIDEV_FLASH, false);
/* Wait for the preceding write to complete. */
status = sst25_waitwritecomplete(priv);
DEBUGASSERT((status & (SST25_SR_WEL|SST25_SR_BP_MASK|SST25_SR_AAI)) == (SST25_SR_WEL|SST25_SR_AAI));
/* Decrement the word count and advance the write position */
nwords--;
@ -785,10 +777,6 @@ static void sst25_wordwrite(struct sst25_dev_s *priv, FAR const uint8_t *buffer,
(buffer[0] != SST25_ERASED_STATE ||
buffer[1] != SST25_ERASED_STATE))
{
/* Wait for the preceding write to complete. */
status = sst25_waitwritecomplete(priv);
DEBUGASSERT((status & (SST25_SR_WEL|SST25_SR_BP_MASK|SST25_SR_AAI)) == (SST25_SR_WEL|SST25_SR_AAI));
/* Select this FLASH part */
@ -806,6 +794,11 @@ static void sst25_wordwrite(struct sst25_dev_s *priv, FAR const uint8_t *buffer,
SPI_SELECT(priv->dev, SPIDEV_FLASH, false);
/* Wait for the preceding write to complete. */
status = sst25_waitwritecomplete(priv);
DEBUGASSERT((status & (SST25_SR_WEL|SST25_SR_BP_MASK|SST25_SR_AAI)) == (SST25_SR_WEL|SST25_SR_AAI));
/* Decrement the word count and advance the write position */
nwords--;
@ -1251,7 +1244,7 @@ FAR struct mtd_dev_s *sst25_initialize(FAR struct spi_dev_s *dev)
/* Make sure that the FLASH is unprotected so that we can write into it */
#ifndef CONFIG_SST25_READONLY
sst25_unprotect(priv->dev);
sst25_unprotect(priv);
#endif
#ifdef CONFIG_SST25_SECTOR512 /* Simulate a 512 byte sector */