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barebox / arch / arm / mach-at91 / at91sam9_reset.S
/*
 * reset AT91SAM9G20 as per errata
 *
 * (C) BitBox Ltd 2010
 *
 * unless the SDRAM is cleanly shutdown before we hit the
 * reset register it can be left driving the data bus and
 * killing the chance of a subsequent boot from NAND
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/linkage.h>
#include <mach/hardware.h>
#include <mach/at91sam9_sdramc.h>
#include <mach/at91_rstc.h>

			.arm

			.globl	restart_sam9

restart_sam9:		ldr	r0, .at91_va_base_sdramc			@ preload constants
			ldr	r1, .at91_va_base_rstc_cr

			mov	r2, #1
			mov	r3, #AT91_SDRAMC_LPCB_POWER_DOWN
			ldr	r4, =AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST

			.balign	32						@ align to cache line

			str	r2, [r0, #AT91_SDRAMC_TR]			@ disable SDRAM access
			str	r3, [r0, #AT91_SDRAMC_LPR]			@ power down SDRAM
			str	r4, [r1]					@ reset processor

			b	.

.at91_va_base_sdramc:
	.word AT91_BASE_SYS + AT91_SDRAMC
.at91_va_base_rstc_cr:
	.word AT91_BASE_SYS + AT91_RSTC_CR