xref: /OK3568_Linux_fs/u-boot/doc/README.cfi (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593SmuzhiyunThe common CFI driver provides this weak default implementation for
2*4882a593Smuzhiyunflash_cmd_reset():
3*4882a593Smuzhiyun
4*4882a593Smuzhiyunstatic void __flash_cmd_reset(flash_info_t *info)
5*4882a593Smuzhiyun{
6*4882a593Smuzhiyun	/*
7*4882a593Smuzhiyun	 * We do not yet know what kind of commandset to use, so we issue
8*4882a593Smuzhiyun	 * the reset command in both Intel and AMD variants, in the hope
9*4882a593Smuzhiyun	 * that AMD flash roms ignore the Intel command.
10*4882a593Smuzhiyun	 */
11*4882a593Smuzhiyun	flash_write_cmd(info, 0, 0, AMD_CMD_RESET);
12*4882a593Smuzhiyun	udelay(1);
13*4882a593Smuzhiyun	flash_write_cmd(info, 0, 0, FLASH_CMD_RESET);
14*4882a593Smuzhiyun}
15*4882a593Smuzhiyunvoid flash_cmd_reset(flash_info_t *info)
16*4882a593Smuzhiyun	__attribute__((weak,alias("__flash_cmd_reset")));
17*4882a593Smuzhiyun
18*4882a593SmuzhiyunSome flash chips seem to have trouble with this reset sequence.
19*4882a593SmuzhiyunIn this case, board-specific code can override this weak default
20*4882a593Smuzhiyunversion with a board-specific function.
21*4882a593Smuzhiyun
22*4882a593SmuzhiyunAt the time of writing, there are two boards that define their own
23*4882a593Smuzhiyunroutine for this.
24*4882a593Smuzhiyun
25*4882a593SmuzhiyunFirst, the digsy_mtc board equipped with the M29W128GH from Numonyx
26*4882a593Smuzhiyunneeds this version to function properly:
27*4882a593Smuzhiyun
28*4882a593Smuzhiyunvoid flash_cmd_reset(flash_info_t *info)
29*4882a593Smuzhiyun{
30*4882a593Smuzhiyun	flash_write_cmd(info, 0, 0, AMD_CMD_RESET);
31*4882a593Smuzhiyun}
32*4882a593Smuzhiyun
33*4882a593SmuzhiyunIn addition, the t3corp board defines the routine thusly:
34*4882a593Smuzhiyun
35*4882a593Smuzhiyunvoid flash_cmd_reset(flash_info_t *info)
36*4882a593Smuzhiyun{
37*4882a593Smuzhiyun	/*
38*4882a593Smuzhiyun	 * FLASH at address CONFIG_SYS_FLASH_BASE is a Spansion chip and
39*4882a593Smuzhiyun	 * needs the Spansion type reset commands. The other flash chip
40*4882a593Smuzhiyun	 * is located behind a FPGA (Xilinx DS617) and needs the Intel type
41*4882a593Smuzhiyun	 * reset command.
42*4882a593Smuzhiyun	 */
43*4882a593Smuzhiyun	if (info->start[0] == CONFIG_SYS_FLASH_BASE)
44*4882a593Smuzhiyun		flash_write_cmd(info, 0, 0, AMD_CMD_RESET);
45*4882a593Smuzhiyun	else
46*4882a593Smuzhiyun		flash_write_cmd(info, 0, 0, FLASH_CMD_RESET);
47*4882a593Smuzhiyun}
48*4882a593Smuzhiyun
49*4882a593Smuzhiyunsee also:
50*4882a593Smuzhiyunhttp://www.mail-archive.com/u-boot@lists.denx.de/msg24368.html
51*4882a593Smuzhiyun
52*4882a593Smuzhiyun
53*4882a593SmuzhiyunConfig Option
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun  CONFIG_SYS_MAX_FLASH_SECT: Number of sectors available on Flash device
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun  CONFIG_SYS_FLASH_CFI_WIDTH: Data-width of the flash device
58*4882a593Smuzhiyun
59*4882a593Smuzhiyun  CONFIG_CMD_FLASH: Enables Flash command library
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun  CONFIG_FLASH_CFI_DRIVER: Enables CFI Flash driver
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun  CONFIG_FLASH_CFI_MTD: Enables MTD frame work for NOR Flash devices
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