2 * (C) Copyright 2000, 2001
3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 * SPDX-License-Identifier: GPL-2.0+
9 * Support for read and write access to EEPROM like memory devices. This
10 * includes regular EEPROM as well as FRAM (ferroelectic nonvolaile RAM).
11 * FRAM devices read and write data at bus speed. In particular, there is no
12 * write delay. Also, there is no limit imposed on the number of bytes that can
13 * be transferred with a single read or write.
15 * Use the following configuration options to ensure no unneeded performance
16 * degradation (typical for EEPROM) is incured for FRAM memory:
18 * #define CONFIG_SYS_I2C_FRAM
19 * #undef CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS
28 #ifndef CONFIG_SYS_I2C_SPEED
29 #define CONFIG_SYS_I2C_SPEED 50000
33 * for CONFIG_SYS_I2C_EEPROM_ADDR_LEN == 2 (16-bit EEPROM address) offset is
34 * 0x000nxxxx for EEPROM address selectors at n, offset xxxx in EEPROM.
36 * for CONFIG_SYS_I2C_EEPROM_ADDR_LEN == 1 (8-bit EEPROM page address) offset is
37 * 0x00000nxx for EEPROM address selectors and page number at n.
39 #if !defined(CONFIG_SPI) || defined(CONFIG_ENV_EEPROM_IS_ON_I2C)
40 #if !defined(CONFIG_SYS_I2C_EEPROM_ADDR_LEN) || \
41 (CONFIG_SYS_I2C_EEPROM_ADDR_LEN < 1) || \
42 (CONFIG_SYS_I2C_EEPROM_ADDR_LEN > 2)
43 #error CONFIG_SYS_I2C_EEPROM_ADDR_LEN must be 1 or 2
47 #if defined(CONFIG_SYS_EEPROM_WREN)
48 extern int eeprom_write_enable (unsigned dev_addr, int state);
51 void eeprom_init(void)
54 #if defined(CONFIG_SPI) && !defined(CONFIG_ENV_EEPROM_IS_ON_I2C)
59 #if defined(CONFIG_HARD_I2C) || defined(CONFIG_SYS_I2C_SOFT)
60 i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
64 static int eeprom_addr(unsigned dev_addr, unsigned offset, uchar *addr)
69 blk_off = offset & 0xff; /* block offset */
70 #if CONFIG_SYS_I2C_EEPROM_ADDR_LEN == 1
71 addr[0] = offset >> 8; /* block number */
72 addr[1] = blk_off; /* block offset */
75 addr[0] = offset >> 16; /* block number */
76 addr[1] = offset >> 8; /* upper address octet */
77 addr[2] = blk_off; /* lower address octet */
79 #endif /* CONFIG_SYS_I2C_EEPROM_ADDR_LEN */
81 addr[0] |= dev_addr; /* insert device address */
86 static int eeprom_rw_block(unsigned offset, uchar *addr, unsigned alen,
87 uchar *buffer, unsigned len, bool read)
92 #if defined(CONFIG_SPI) && !defined(CONFIG_ENV_EEPROM_IS_ON_I2C)
94 spi_read(addr, alen, buffer, len);
96 spi_write(addr, alen, buffer, len);
99 #if defined(CONFIG_SYS_I2C_EEPROM_BUS)
100 i2c_set_bus_num(CONFIG_SYS_I2C_EEPROM_BUS);
104 ret = i2c_read(addr[0], offset, alen - 1, buffer, len);
106 ret = i2c_write(addr[0], offset, alen - 1, buffer, len);
114 int eeprom_read (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cnt)
116 unsigned end = offset + cnt;
122 * Read data until done or would cross a page boundary.
123 * We must write the address again when changing pages
124 * because the next page may be in a different device.
126 while (offset < end) {
128 #if !defined(CONFIG_SYS_I2C_FRAM)
132 blk_off = offset & 0xFF; /* block offset */
133 alen = eeprom_addr(dev_addr, offset, addr);
138 * For a FRAM device there is no limit on the number of the
139 * bytes that can be ccessed with the single read or write
142 #if !defined(CONFIG_SYS_I2C_FRAM)
143 maxlen = 0x100 - blk_off;
144 if (maxlen > I2C_RXTX_LEN)
145 maxlen = I2C_RXTX_LEN;
150 rcode = eeprom_rw_block(offset, addr, alen, buffer, len, 1);
159 int eeprom_write (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cnt)
161 unsigned end = offset + cnt;
166 #if defined(CONFIG_SYS_EEPROM_WREN)
167 eeprom_write_enable (dev_addr,1);
170 * Write data until done or would cross a write page boundary.
171 * We must write the address again when changing pages
172 * because the address counter only increments within a page.
175 while (offset < end) {
177 #if !defined(CONFIG_SYS_I2C_FRAM)
181 blk_off = offset & 0xFF; /* block offset */
182 alen = eeprom_addr(dev_addr, offset, addr);
187 * For a FRAM device there is no limit on the number of the
188 * bytes that can be accessed with the single read or write
191 #if !defined(CONFIG_SYS_I2C_FRAM)
193 #if defined(CONFIG_SYS_EEPROM_PAGE_WRITE_BITS)
195 #define EEPROM_PAGE_SIZE (1 << CONFIG_SYS_EEPROM_PAGE_WRITE_BITS)
196 #define EEPROM_PAGE_OFFSET(x) ((x) & (EEPROM_PAGE_SIZE - 1))
198 maxlen = EEPROM_PAGE_SIZE - EEPROM_PAGE_OFFSET(blk_off);
200 maxlen = 0x100 - blk_off;
202 if (maxlen > I2C_RXTX_LEN)
203 maxlen = I2C_RXTX_LEN;
209 rcode = eeprom_rw_block(offset, addr, alen, buffer, len, 0);
214 #if defined(CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS)
215 udelay(CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS * 1000);
218 #if defined(CONFIG_SYS_EEPROM_WREN)
219 eeprom_write_enable (dev_addr,0);
224 static int do_eeprom(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
226 const char *const fmt =
227 "\nEEPROM @0x%lX %s: addr %08lx off %04lx count %ld ... ";
228 char * const *args = &argv[2];
230 ulong dev_addr, addr, off, cnt;
233 #ifdef CONFIG_SYS_DEF_EEPROM_ADDR
235 dev_addr = CONFIG_SYS_DEF_EEPROM_ADDR;
239 dev_addr = simple_strtoul(*args++, NULL, 16);
242 return CMD_RET_USAGE;
245 addr = simple_strtoul(*args++, NULL, 16);
246 off = simple_strtoul(*args++, NULL, 16);
247 cnt = simple_strtoul(*args++, NULL, 16);
249 # if !defined(CONFIG_SPI) || defined(CONFIG_ENV_EEPROM_IS_ON_I2C)
251 # endif /* !CONFIG_SPI */
253 if (strcmp (argv[1], "read") == 0) {
254 printf(fmt, dev_addr, argv[1], addr, off, cnt);
256 rcode = eeprom_read(dev_addr, off, (uchar *) addr, cnt);
260 } else if (strcmp (argv[1], "write") == 0) {
261 printf(fmt, dev_addr, argv[1], addr, off, cnt);
263 rcode = eeprom_write(dev_addr, off, (uchar *) addr, cnt);
269 return CMD_RET_USAGE;
273 eeprom, 6, 1, do_eeprom,
275 "read devaddr addr off cnt\n"
276 "eeprom write devaddr addr off cnt\n"
277 " - read/write `cnt' bytes from `devaddr` EEPROM at offset `off'"