aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-at91/at91sam9_alt_reset.S
blob: e0256deb91fbfd7acc478e29609831fcfdf39c12 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
/*
 * 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 <asm/system.h>
#include <mach/hardware.h>
#include <mach/at91sam9_sdramc.h>
#include <mach/at91_rstc.h>

			.arm

			.globl	at91sam9_alt_reset

at91sam9_alt_reset:	mrc	p15, 0, r0, c1, c0, 0
			orr	r0, r0, #CR_I
			mcr	p15, 0, r0, c1, c0, 0		@ enable I-cache

			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_VA_BASE_SYS + AT91_SDRAMC0
.at91_va_base_rstc_cr:
	.word AT91_VA_BASE_SYS + AT91_RSTC_CR