diff options
Diffstat (limited to 'common/cmd_eeprom.c')
| -rw-r--r-- | common/cmd_eeprom.c | 60 |
1 files changed, 56 insertions, 4 deletions
diff --git a/common/cmd_eeprom.c b/common/cmd_eeprom.c index 80b8ccc1e..d15a41205 100644 --- a/common/cmd_eeprom.c +++ b/common/cmd_eeprom.c @@ -22,6 +22,21 @@ * */ +/* + * Support for read and write access to EEPROM like memory devices. This + * includes regular EEPROM as well as FRAM (ferroelectic nonvolaile RAM). + * FRAM devices read and write data at bus speed. In particular, there is no + * write delay. Also, there is no limit imposed on the numer of bytes that can + * be transferred with a single read or write. + * + * Use the following configuration options to ensure no unneeded performance + * degradation (typical for EEPROM) is incured for FRAM memory: + * + * #define CFG_I2C_FRAM + * #undef CFG_EEPROM_PAGE_WRITE_DELAY_MS + * + */ + #include <common.h> #include <config.h> #include <command.h> @@ -34,6 +49,9 @@ extern int eeprom_read (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cnt); extern int eeprom_write (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cnt); +#if defined(CFG_EEPROM_WREN) +extern int eeprom_write_enable (unsigned dev_addr, int state); +#endif #endif @@ -122,7 +140,11 @@ int eeprom_read (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cnt * because the next page may be in a different device. */ while (offset < end) { - unsigned alen, len, maxlen; + unsigned alen, len; +#if !defined(CFG_I2C_FRAM) + unsigned maxlen; +#endif + #if CFG_I2C_EEPROM_ADDR_LEN == 1 && !defined(CONFIG_SPI_X) uchar addr[2]; @@ -144,12 +166,21 @@ int eeprom_read (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cnt addr[0] |= dev_addr; /* insert device address */ + len = end - offset; + + /* + * For a FRAM device there is no limit on the number of the + * bytes that can be ccessed with the single read or write + * operation. + */ +#if !defined(CFG_I2C_FRAM) maxlen = 0x100 - blk_off; if (maxlen > I2C_RXTX_LEN) maxlen = I2C_RXTX_LEN; - len = end - offset; if (len > maxlen) len = maxlen; +#endif + #ifdef CONFIG_SPI spi_read (addr, alen, buffer, len); #else @@ -159,6 +190,7 @@ int eeprom_read (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cnt buffer += len; offset += len; } + return rcode; } @@ -185,13 +217,20 @@ int eeprom_write (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cn int i; #endif +#if defined(CFG_EEPROM_WREN) + eeprom_write_enable (dev_addr,1); +#endif /* Write data until done or would cross a write page boundary. * We must write the address again when changing pages * because the address counter only increments within a page. */ while (offset < end) { - unsigned alen, len, maxlen; + unsigned alen, len; +#if !defined(CFG_I2C_FRAM) + unsigned maxlen; +#endif + #if CFG_I2C_EEPROM_ADDR_LEN == 1 && !defined(CONFIG_SPI_X) uchar addr[2]; @@ -213,6 +252,15 @@ int eeprom_write (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cn addr[0] |= dev_addr; /* insert device address */ + len = end - offset; + + /* + * For a FRAM device there is no limit on the number of the + * bytes that can be ccessed with the single read or write + * operation. + */ +#if !defined(CFG_I2C_FRAM) + #if defined(CFG_EEPROM_PAGE_WRITE_BITS) #define EEPROM_PAGE_SIZE (1 << CFG_EEPROM_PAGE_WRITE_BITS) @@ -225,9 +273,10 @@ int eeprom_write (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cn if (maxlen > I2C_RXTX_LEN) maxlen = I2C_RXTX_LEN; - len = end - offset; if (len > maxlen) len = maxlen; +#endif + #ifdef CONFIG_SPI spi_write (addr, alen, buffer, len); #else @@ -324,6 +373,9 @@ int eeprom_write (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cn udelay(CFG_EEPROM_PAGE_WRITE_DELAY_MS * 1000); #endif } +#if defined(CFG_EEPROM_WREN) + eeprom_write_enable (dev_addr,0); +#endif return rcode; } |