linux/arch/arm/mach-at91/at91sam9g45_reset.S
Jean-Christophe PLAGNIOL-VILLARD bd737fea4e ARM: at91: sam9g45: shutdown ddr1 too when rebooting
Like we are doing on DDR0 we need to cleanly shutdown DDR1 if it is
used before rebooting.
If DDR1 is not initialized, we check it and avoid dereferencing its address.
Even by adding two more instructions, we are able to complete the procedure
within a single cache line.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
2013-09-30 09:58:44 -07:00

46 lines
1.2 KiB
ArmAsm

/*
* reset AT91SAM9G45 as per errata
*
* Copyright (C) 2011 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcosoft.com>
*
* 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
*
* GPLv2 Only
*/
#include <linux/linkage.h>
#include <mach/hardware.h>
#include <mach/at91_ramc.h>
#include "at91_rstc.h"
.arm
/*
* at91_ramc_base is an array void*
* init at NULL if only one DDR controler is present in or DT
*/
.globl at91sam9g45_restart
at91sam9g45_restart:
ldr r5, =at91_ramc_base @ preload constants
ldr r0, [r5]
ldr r5, [r5, #4] @ ddr1
cmp r5, #0
ldr r4, =at91_rstc_base
ldr r1, [r4]
mov r2, #1
mov r3, #AT91_DDRSDRC_LPCB_POWER_DOWN
ldr r4, =AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST
.balign 32 @ align to cache line
strne r2, [r5, #AT91_DDRSDRC_RTR] @ disable DDR1 access
strne r3, [r5, #AT91_DDRSDRC_LPR] @ power down DDR1
str r2, [r0, #AT91_DDRSDRC_RTR] @ disable DDR0 access
str r3, [r0, #AT91_DDRSDRC_LPR] @ power down DDR0
str r4, [r1, #AT91_RSTC_CR] @ reset processor
b .