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doc/README.cfi: Update code snippet, and add example.

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First, update the code snippet referenced in the README file. And
since there are only two boards that override flash_cmd_reset(),
might as well show them both.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
This commit is contained in:
Robert P. J. Day 2016-12-29 05:23:19 -05:00 • committed by Tom Rini
parent b352548890
commit 66723eda4e
1 changed files with 26 additions and 5 deletions
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31
doc/README.cfi
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@ -1,7 +1,7 @@
The common CFI driver provides this weak default implementation for The common CFI driver provides this weak default implementation for
flash_cmd_reset(): flash_cmd_reset():
void __flash_cmd_reset(flash_info_t *info) static void __flash_cmd_reset(flash_info_t *info)
{ {
/* /*
* We do not yet know what kind of commandset to use, so we issue * We do not yet know what kind of commandset to use, so we issue
@ -9,22 +9,43 @@ void __flash_cmd_reset(flash_info_t *info)
* that AMD flash roms ignore the Intel command. * that AMD flash roms ignore the Intel command.
*/ */
flash_write_cmd(info, 0, 0, AMD_CMD_RESET); flash_write_cmd(info, 0, 0, AMD_CMD_RESET);
udelay(1);
flash_write_cmd(info, 0, 0, FLASH_CMD_RESET); flash_write_cmd(info, 0, 0, FLASH_CMD_RESET);
} }
void flash_cmd_reset(flash_info_t *info) void flash_cmd_reset(flash_info_t *info)
__attribute__((weak,alias("__flash_cmd_reset"))); __attribute__((weak,alias("__flash_cmd_reset")));
Some flash chips seem to have trouble with this reset sequence.
In this case, board-specific code can override this weak default
version with a board-specific function.
Some flash chips seems to have trouble with this reset sequence. In this case At the time of writing, there are two boards that define their own
the board specific code can override this weak default version with a board routine for this.
specific function. For example the digsy_mtc board equipped with the M29W128GH
from Numonyx needs this version to function properly: First, the digsy_mtc board equipped with the M29W128GH from Numonyx
needs this version to function properly:
void flash_cmd_reset(flash_info_t *info) void flash_cmd_reset(flash_info_t *info)
{ {
flash_write_cmd(info, 0, 0, AMD_CMD_RESET); flash_write_cmd(info, 0, 0, AMD_CMD_RESET);
} }
In addition, the t3corp board defines the routine thusly:
void flash_cmd_reset(flash_info_t *info)
{
/*
* FLASH at address CONFIG_SYS_FLASH_BASE is a Spansion chip and
* needs the Spansion type reset commands. The other flash chip
* is located behind a FPGA (Xilinx DS617) and needs the Intel type
* reset command.
*/
if (info->start[0] == CONFIG_SYS_FLASH_BASE)
flash_write_cmd(info, 0, 0, AMD_CMD_RESET);
else
flash_write_cmd(info, 0, 0, FLASH_CMD_RESET);
}
see also: see also:
http://www.mail-archive.com/u-boot@lists.denx.de/msg24368.html http://www.mail-archive.com/u-boot@lists.denx.de/msg24368.html