| Nicolas Ferre | 1345562 | 2010-10-14 17:19:11 +0200 | [diff] [blame] | 1 | /* |
| 2 | * reset AT91SAM9G20 as per errata |
| 3 | * |
| 4 | * (C) BitBox Ltd 2010 |
| 5 | * |
| 6 | * unless the SDRAM is cleanly shutdown before we hit the |
| 7 | * reset register it can be left driving the data bus and |
| 8 | * killing the chance of a subsequent boot from NAND |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify |
| 11 | * it under the terms of the GNU General Public License as published by |
| 12 | * the Free Software Foundation; either version 2 of the License, or |
| 13 | * (at your option) any later version. |
| 14 | */ |
| 15 | |
| 16 | #include <linux/linkage.h> |
| 17 | #include <asm/system.h> |
| 18 | #include <mach/hardware.h> |
| 19 | #include <mach/at91sam9_sdramc.h> |
| 20 | #include <mach/at91_rstc.h> |
| 21 | |
| 22 | .arm |
| 23 | |
| 24 | .globl at91sam9_alt_reset |
| 25 | |
| 26 | at91sam9_alt_reset: mrc p15, 0, r0, c1, c0, 0 |
| 27 | orr r0, r0, #CR_I |
| 28 | mcr p15, 0, r0, c1, c0, 0 @ enable I-cache |
| 29 | |
| 30 | ldr r0, .at91_va_base_sdramc @ preload constants |
| 31 | ldr r1, .at91_va_base_rstc_cr |
| 32 | |
| 33 | mov r2, #1 |
| 34 | mov r3, #AT91_SDRAMC_LPCB_POWER_DOWN |
| 35 | ldr r4, =AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST |
| 36 | |
| 37 | .balign 32 @ align to cache line |
| 38 | |
| 39 | str r2, [r0, #AT91_SDRAMC_TR] @ disable SDRAM access |
| 40 | str r3, [r0, #AT91_SDRAMC_LPR] @ power down SDRAM |
| 41 | str r4, [r1] @ reset processor |
| 42 | |
| 43 | b . |
| 44 | |
| 45 | .at91_va_base_sdramc: |
| 46 | .word AT91_VA_BASE_SYS + AT91_SDRAMC0 |
| 47 | .at91_va_base_rstc_cr: |
| 48 | .word AT91_VA_BASE_SYS + AT91_RSTC_CR |