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