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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
View file

@ -1,7 +1,7 @@
The common CFI driver provides this weak default implementation for
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
@ -9,22 +9,43 @@ void __flash_cmd_reset(flash_info_t *info)
* that AMD flash roms ignore the Intel command.
*/
flash_write_cmd(info, 0, 0, AMD_CMD_RESET);
udelay(1);
flash_write_cmd(info, 0, 0, FLASH_CMD_RESET);
}
void flash_cmd_reset(flash_info_t *info)
__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
the board specific code can override this weak default version with a board
specific function. For example the digsy_mtc board equipped with the M29W128GH
from Numonyx needs this version to function properly:
At the time of writing, there are two boards that define their own
routine for this.
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)
{
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:
http://www.mail-archive.com/u-boot@lists.denx.de/msg24368.html