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 int eeprom_read (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cnt)
66 unsigned end = offset + cnt;
71 * Read data until done or would cross a page boundary.
72 * We must write the address again when changing pages
73 * because the next page may be in a different device.
75 while (offset < end) {
77 #if !defined(CONFIG_SYS_I2C_FRAM)
81 #if CONFIG_SYS_I2C_EEPROM_ADDR_LEN == 1 && !defined(CONFIG_SPI_X)
84 blk_off = offset & 0xFF; /* block offset */
86 addr[0] = offset >> 8; /* block number */
87 addr[1] = blk_off; /* block offset */
92 blk_off = offset & 0xFF; /* block offset */
94 addr[0] = offset >> 16; /* block number */
95 addr[1] = offset >> 8; /* upper address octet */
96 addr[2] = blk_off; /* lower address octet */
98 #endif /* CONFIG_SYS_I2C_EEPROM_ADDR_LEN, CONFIG_SPI_X */
100 addr[0] |= dev_addr; /* insert device address */
105 * For a FRAM device there is no limit on the number of the
106 * bytes that can be ccessed with the single read or write
109 #if !defined(CONFIG_SYS_I2C_FRAM)
110 maxlen = 0x100 - blk_off;
111 if (maxlen > I2C_RXTX_LEN)
112 maxlen = I2C_RXTX_LEN;
117 #if defined(CONFIG_SPI) && !defined(CONFIG_ENV_EEPROM_IS_ON_I2C)
118 spi_read (addr, alen, buffer, len);
120 #if defined(CONFIG_SYS_I2C_EEPROM_BUS)
121 i2c_set_bus_num(CONFIG_SYS_I2C_EEPROM_BUS);
123 if (i2c_read(addr[0], offset, alen - 1, buffer, len))
133 int eeprom_write (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cnt)
135 unsigned end = offset + cnt;
139 #if defined(CONFIG_SYS_EEPROM_WREN)
140 eeprom_write_enable (dev_addr,1);
143 * Write data until done or would cross a write page boundary.
144 * We must write the address again when changing pages
145 * because the address counter only increments within a page.
148 while (offset < end) {
150 #if !defined(CONFIG_SYS_I2C_FRAM)
154 #if CONFIG_SYS_I2C_EEPROM_ADDR_LEN == 1 && !defined(CONFIG_SPI_X)
157 blk_off = offset & 0xFF; /* block offset */
159 addr[0] = offset >> 8; /* block number */
160 addr[1] = blk_off; /* block offset */
165 blk_off = offset & 0xFF; /* block offset */
167 addr[0] = offset >> 16; /* block number */
168 addr[1] = offset >> 8; /* upper address octet */
169 addr[2] = blk_off; /* lower address octet */
171 #endif /* CONFIG_SYS_I2C_EEPROM_ADDR_LEN, CONFIG_SPI_X */
173 addr[0] |= dev_addr; /* insert device address */
178 * For a FRAM device there is no limit on the number of the
179 * bytes that can be accessed with the single read or write
182 #if !defined(CONFIG_SYS_I2C_FRAM)
184 #if defined(CONFIG_SYS_EEPROM_PAGE_WRITE_BITS)
186 #define EEPROM_PAGE_SIZE (1 << CONFIG_SYS_EEPROM_PAGE_WRITE_BITS)
187 #define EEPROM_PAGE_OFFSET(x) ((x) & (EEPROM_PAGE_SIZE - 1))
189 maxlen = EEPROM_PAGE_SIZE - EEPROM_PAGE_OFFSET(blk_off);
191 maxlen = 0x100 - blk_off;
193 if (maxlen > I2C_RXTX_LEN)
194 maxlen = I2C_RXTX_LEN;
200 #if defined(CONFIG_SPI) && !defined(CONFIG_ENV_EEPROM_IS_ON_I2C)
201 spi_write (addr, alen, buffer, len);
204 #if defined(CONFIG_SYS_I2C_EEPROM_BUS)
205 i2c_set_bus_num(CONFIG_SYS_I2C_EEPROM_BUS);
207 if (i2c_write(addr[0], offset, alen - 1, buffer, len))
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 #if !defined(CONFIG_SPI) || defined(CONFIG_ENV_EEPROM_IS_ON_I2C)
225 int eeprom_probe(unsigned dev_addr, unsigned offset)
229 /* Probe the chip address
231 #if CONFIG_SYS_I2C_EEPROM_ADDR_LEN == 1 && !defined(CONFIG_SPI_X)
232 chip = offset >> 8; /* block number */
234 chip = offset >> 16; /* block number */
235 #endif /* CONFIG_SYS_I2C_EEPROM_ADDR_LEN, CONFIG_SPI_X */
237 chip |= dev_addr; /* insert device address */
239 return (i2c_probe (chip));
243 static int do_eeprom(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
245 const char *const fmt =
246 "\nEEPROM @0x%lX %s: addr %08lx off %04lx count %ld ... ";
247 char * const *args = &argv[2];
249 ulong dev_addr, addr, off, cnt;
252 #ifdef CONFIG_SYS_DEF_EEPROM_ADDR
254 dev_addr = CONFIG_SYS_DEF_EEPROM_ADDR;
258 dev_addr = simple_strtoul(*args++, NULL, 16);
261 return CMD_RET_USAGE;
264 addr = simple_strtoul(*args++, NULL, 16);
265 off = simple_strtoul(*args++, NULL, 16);
266 cnt = simple_strtoul(*args++, NULL, 16);
268 # if !defined(CONFIG_SPI) || defined(CONFIG_ENV_EEPROM_IS_ON_I2C)
270 # endif /* !CONFIG_SPI */
272 if (strcmp (argv[1], "read") == 0) {
273 printf(fmt, dev_addr, argv[1], addr, off, cnt);
275 rcode = eeprom_read(dev_addr, off, (uchar *) addr, cnt);
279 } else if (strcmp (argv[1], "write") == 0) {
280 printf(fmt, dev_addr, argv[1], addr, off, cnt);
282 rcode = eeprom_write(dev_addr, off, (uchar *) addr, cnt);
288 return CMD_RET_USAGE;
292 eeprom, 6, 1, do_eeprom,
294 "read devaddr addr off cnt\n"
295 "eeprom write devaddr addr off cnt\n"
296 " - read/write `cnt' bytes from `devaddr` EEPROM at offset `off'"