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
32 #ifndef CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS
33 #define CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS 0
36 #ifndef CONFIG_SYS_EEPROM_PAGE_WRITE_BITS
37 #define CONFIG_SYS_EEPROM_PAGE_WRITE_BITS 8
40 #define EEPROM_PAGE_SIZE (1 << CONFIG_SYS_EEPROM_PAGE_WRITE_BITS)
41 #define EEPROM_PAGE_OFFSET(x) ((x) & (EEPROM_PAGE_SIZE - 1))
44 * for CONFIG_SYS_I2C_EEPROM_ADDR_LEN == 2 (16-bit EEPROM address) offset is
45 * 0x000nxxxx for EEPROM address selectors at n, offset xxxx in EEPROM.
47 * for CONFIG_SYS_I2C_EEPROM_ADDR_LEN == 1 (8-bit EEPROM page address) offset is
48 * 0x00000nxx for EEPROM address selectors and page number at n.
50 #if !defined(CONFIG_SPI) || defined(CONFIG_ENV_EEPROM_IS_ON_I2C)
51 #if !defined(CONFIG_SYS_I2C_EEPROM_ADDR_LEN) || \
52 (CONFIG_SYS_I2C_EEPROM_ADDR_LEN < 1) || \
53 (CONFIG_SYS_I2C_EEPROM_ADDR_LEN > 2)
54 #error CONFIG_SYS_I2C_EEPROM_ADDR_LEN must be 1 or 2
58 __weak int eeprom_write_enable(unsigned dev_addr, int state)
63 void eeprom_init(void)
66 #if defined(CONFIG_SPI) && !defined(CONFIG_ENV_EEPROM_IS_ON_I2C)
71 #if defined(CONFIG_HARD_I2C) || defined(CONFIG_SYS_I2C_SOFT)
72 i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
76 static int eeprom_addr(unsigned dev_addr, unsigned offset, uchar *addr)
81 blk_off = offset & 0xff; /* block offset */
82 #if CONFIG_SYS_I2C_EEPROM_ADDR_LEN == 1
83 addr[0] = offset >> 8; /* block number */
84 addr[1] = blk_off; /* block offset */
87 addr[0] = offset >> 16; /* block number */
88 addr[1] = offset >> 8; /* upper address octet */
89 addr[2] = blk_off; /* lower address octet */
91 #endif /* CONFIG_SYS_I2C_EEPROM_ADDR_LEN */
93 addr[0] |= dev_addr; /* insert device address */
98 static int eeprom_len(unsigned offset, unsigned end)
100 unsigned len = end - offset;
103 * For a FRAM device there is no limit on the number of the
104 * bytes that can be ccessed with the single read or write
107 #if !defined(CONFIG_SYS_I2C_FRAM)
108 unsigned blk_off = offset & 0xff;
109 unsigned maxlen = EEPROM_PAGE_SIZE - EEPROM_PAGE_OFFSET(blk_off);
111 if (maxlen > I2C_RXTX_LEN)
112 maxlen = I2C_RXTX_LEN;
121 static int eeprom_rw_block(unsigned offset, uchar *addr, unsigned alen,
122 uchar *buffer, unsigned len, bool read)
127 #if defined(CONFIG_SPI) && !defined(CONFIG_ENV_EEPROM_IS_ON_I2C)
129 spi_read(addr, alen, buffer, len);
131 spi_write(addr, alen, buffer, len);
134 #if defined(CONFIG_SYS_I2C_EEPROM_BUS)
135 i2c_set_bus_num(CONFIG_SYS_I2C_EEPROM_BUS);
139 ret = i2c_read(addr[0], offset, alen - 1, buffer, len);
141 ret = i2c_write(addr[0], offset, alen - 1, buffer, len);
149 int eeprom_read (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cnt)
151 unsigned end = offset + cnt;
156 * Read data until done or would cross a page boundary.
157 * We must write the address again when changing pages
158 * because the next page may be in a different device.
160 while (offset < end) {
163 alen = eeprom_addr(dev_addr, offset, addr);
165 len = eeprom_len(offset, end);
167 rcode = eeprom_rw_block(offset, addr, alen, buffer, len, 1);
176 int eeprom_write (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cnt)
178 unsigned end = offset + cnt;
182 eeprom_write_enable(dev_addr, 1);
185 * Write data until done or would cross a write page boundary.
186 * We must write the address again when changing pages
187 * because the address counter only increments within a page.
190 while (offset < end) {
193 alen = eeprom_addr(dev_addr, offset, addr);
195 len = eeprom_len(offset, end);
197 rcode = eeprom_rw_block(offset, addr, alen, buffer, len, 0);
202 udelay(CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS * 1000);
205 eeprom_write_enable(dev_addr, 0);
210 static int do_eeprom(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
212 const char *const fmt =
213 "\nEEPROM @0x%lX %s: addr %08lx off %04lx count %ld ... ";
214 char * const *args = &argv[2];
216 ulong dev_addr, addr, off, cnt;
219 #ifdef CONFIG_SYS_DEF_EEPROM_ADDR
221 dev_addr = CONFIG_SYS_DEF_EEPROM_ADDR;
225 dev_addr = simple_strtoul(*args++, NULL, 16);
228 return CMD_RET_USAGE;
231 addr = simple_strtoul(*args++, NULL, 16);
232 off = simple_strtoul(*args++, NULL, 16);
233 cnt = simple_strtoul(*args++, NULL, 16);
237 if (strcmp (argv[1], "read") == 0) {
238 printf(fmt, dev_addr, argv[1], addr, off, cnt);
240 rcode = eeprom_read(dev_addr, off, (uchar *) addr, cnt);
244 } else if (strcmp (argv[1], "write") == 0) {
245 printf(fmt, dev_addr, argv[1], addr, off, cnt);
247 rcode = eeprom_write(dev_addr, off, (uchar *) addr, cnt);
253 return CMD_RET_USAGE;
257 eeprom, 6, 1, do_eeprom,
259 "read devaddr addr off cnt\n"
260 "eeprom write devaddr addr off cnt\n"
261 " - read/write `cnt' bytes from `devaddr` EEPROM at offset `off'"