xref: /openbmc/u-boot/doc/README.cfi (revision 643aae14)
1 The common CFI driver provides this weak default implementation for
2 flash_cmd_reset():
3 
4 void __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 }
14 void flash_cmd_reset(flash_info_t *info)
15 	__attribute__((weak,alias("__flash_cmd_reset")));
16 
17 
18 Some flash chips seems to have trouble with this reset sequence. In this case
19 the board specific code can override this weak default version with a board
20 specific function. For example the digsy_mtc board equipped with the M29W128GH
21 from Numonyx needs this version to function properly:
22 
23 void flash_cmd_reset(flash_info_t *info)
24 {
25 	flash_write_cmd(info, 0, 0, AMD_CMD_RESET);
26 }
27 
28 see also:
29 http://www.mail-archive.com/u-boot@lists.denx.de/msg24368.html
30