diff options
Diffstat (limited to 'arch/arm/mach-at91/at91sam9_alt_reset.S')
| -rw-r--r-- | arch/arm/mach-at91/at91sam9_alt_reset.S | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/arch/arm/mach-at91/at91sam9_alt_reset.S b/arch/arm/mach-at91/at91sam9_alt_reset.S new file mode 100644 index 00000000000..e0256deb91f --- /dev/null +++ b/arch/arm/mach-at91/at91sam9_alt_reset.S @@ -0,0 +1,48 @@ +/* + * 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 |