xref: /openbmc/u-boot/doc/README.cfi (revision 3e9aa320)
1The common CFI driver provides this weak default implementation for
2flash_cmd_reset():
3
4void __flash_cmd_reset(flash_info_t *info)
5{
6	/*
7	 * We do not yet know what kind of commandset to use, so we issue
8	 * the reset command in both Intel and AMD variants, in the hope
9	 * that AMD flash roms ignore the Intel command.
10	 */
11	flash_write_cmd(info, 0, 0, AMD_CMD_RESET);
12	flash_write_cmd(info, 0, 0, FLASH_CMD_RESET);
13}
14void flash_cmd_reset(flash_info_t *info)
15	__attribute__((weak,alias("__flash_cmd_reset")));
16
17
18Some flash chips seems to have trouble with this reset sequence. In this case
19the board specific code can override this weak default version with a board
20specific function. For example the digsy_mtc board equipped with the M29W128GH
21from Numonyx needs this version to function properly:
22
23void flash_cmd_reset(flash_info_t *info)
24{
25	flash_write_cmd(info, 0, 0, AMD_CMD_RESET);
26}
27
28see also:
29http://www.mail-archive.com/u-boot@lists.denx.de/msg24368.html
30
31
32Config Option
33
34  CONFIG_SYS_MAX_FLASH_SECT: Number of sectors available on Flash device
35
36  CONFIG_SYS_FLASH_CFI_WIDTH: Data-width of the flash device
37
38  CONFIG_CMD_FLASH: Enables Flash command library
39
40  CONFIG_FLASH_CFI_DRIVER: Enables CFI Flash driver
41
42  CONFIG_FLASH_CFI_MTD: Enables MTD frame work for NOR Flash devices
43