sysmo-bts
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barebox
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FRAM memory access optimization.

This commit is contained in:
2005-08-12 21:16:13 +02:00
parent 6df6d38d2d
commit d4f5c72896
3 changed files with 54 additions and 4 deletions
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51
common/cmd_eeprom.c
View File

@ -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>
@ -122,7 +137,11 @@ 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 +163,21 @@ 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 +187,7 @@ int eeprom_read (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cnt
buffer += len;
offset += len;
}
return rcode;
}
@ -191,7 +220,11 @@ int eeprom_write (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cn
*/
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 +246,15 @@ 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 +267,10 @@ 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

6
common/cmd_i2c.c
View File

@ -295,7 +295,13 @@ int do_i2c_mw ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
* chip doesn't respond. This apparently isn't a
* universal feature so we don't take advantage of it.
*/
/*
* No write delay with FRAM devices.
*/
#if !defined(CFG_I2C_FRAM)
udelay(11000);
#endif
#if 0
for(timeout = 0; timeout < 10; timeout++) {
udelay(2000);

1
include/configs/o2dnt.h
View File

@ -158,6 +158,7 @@
* 0x50 ... 0x57 each 256 bytes in size
*
*/
#define CFG_I2C_FRAM
#define CFG_I2C_EEPROM_ADDR 0x50 /* 1010000x */
#define CFG_I2C_EEPROM_ADDR_LEN 1
#define CFG_EEPROM_PAGE_WRITE_BITS 3