/* * reset.c - logic for resetting the cpu * * Copyright (c) 2005-2008 Analog Devices Inc. * * Licensed under the GPL-2 or later. */ #include <common.h> #include <command.h> #include <asm/blackfin.h> #include "cpu.h" /* A system soft reset makes external memory unusable so force * this function into L1. We use the compiler ssync here rather * than SSYNC() because it's safe (no interrupts and such) and * we save some L1. We do not need to force sanity in the SYSCR * register as the BMODE selection bit is cleared by the soft * reset while the Core B bit (on dual core parts) is cleared by * the core reset. */ __attribute__ ((__l1_text__, __noreturn__)) void bfin_reset(void) { /* Wait for completion of "system" events such as cache line * line fills so that we avoid infinite stalls later on as * much as possible. This code is in L1, so it won't trigger * any such event after this point in time. */ __builtin_bfin_ssync(); while (1) { /* Initiate System software reset. */ bfin_write_SWRST(0x7); /* Due to the way reset is handled in the hardware, we need * to delay for 7 SCLKS. The only reliable way to do this is * to calculate the CCLK/SCLK ratio and multiply 7. For now, * we'll assume worse case which is a 1:15 ratio. */ asm( "LSETUP (1f, 1f) LC0 = %0\n" "1: nop;" : : "a" (15 * 7) : "LC0", "LB0", "LT0" ); /* Clear System software reset */ bfin_write_SWRST(0); /* Wait for the SWRST write to complete. Cannot rely on SSYNC * though as the System state is all reset now. */ asm( "LSETUP (1f, 1f) LC1 = %0\n" "1: nop;" : : "a" (15 * 1) : "LC1", "LB1", "LT1" ); /* Issue core reset */ asm("raise 1"); } } /* We need to trampoline ourselves up into L1 since our linker * does not have relaxtion support and will only generate a * PC relative call with a 25 bit immediate. This is not enough * to get us from the top of SDRAM into L1. */ __attribute__ ((__noreturn__)) static inline void bfin_reset_trampoline(void) { if (board_reset) board_reset(); while (1) asm("jump (%0);" : : "a" (bfin_reset)); } __attribute__ ((__noreturn__)) void bfin_reset_or_hang(void) { #ifdef CONFIG_PANIC_HANG hang(); #else bfin_reset_trampoline(); #endif } int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) { bfin_reset_trampoline(); return 0; }