Hello all,
for a Zynq (7-series) ARM based system I would like to implement a board-specific reset function.
There are a few existing slightly different methods in place (see below). What is the preferred way and place?
My current feeling is overriding reset_misc() in board.c, i.e. method #4 from the existings methods I found in U-Boot, see below.
1) There used to be a call-out from the CPU reset to the board_reset() if CONFIG_BOARD_RESET was defined non-zero, like this:
arch/powerpc/cpu/ppc4xx/cpu.c:
<...> void board_reset(void); <...> int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { #if defined(CONFIG_BOARD_RESET) board_reset(); <...>
This only existed for ppc4xx (which I think has been obsoleted now).
2) Blackfin seems to define a weak label "board_reset", and this (function) pointer is compared against non-NULL, called if non-NULL.
arch/blackfin/cpu/reset.c:88: if (board_reset) arch/blackfin/cpu/reset.c:89: board_reset(); arch/blackfin/cpu/cpu.h:14:void board_reset(void) __attribute__((__weak__));
3) PowerPC MPC85xx seems to define a weak label, and alias it to a __board_reset();
arch/powerpc/cpu/mpc85xx/cpu.c:33:__board_reset(void) arch/powerpc/cpu/mpc85xx/cpu.c:37:void board_reset(void) __attribute__((weak, alias("__board_reset"))); arch/powerpc/cpu/mpc85xx/cpu.c:315: board_reset();
/* * Default board reset function */ static void __board_reset(void) { /* Do nothing */ } void board_reset(void) __attribute__((weak, alias("__board_reset")));
4) Similarly but a bit hidden for my "grep board_reset", is reset_misc() in arch/arm/lib/reset.c:
#include <common.h>
__weak void reset_misc(void) { }
int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { puts ("resetting ...\n");
udelay (50000); /* wait 50 ms */
disable_interrupts();
reset_misc();
Thanks,
Leon.