freebsd-dev/sys/arm/at91/at91_reset.S
Olivier Houchard 4ad6106939 if_ate.c:
* Support for sam9 "EMAC" controller.
    * Support for rmii interface to phy.

at91.c & at91sam9.c:

    * Eliminate separate at91sam9.c file.
    * Add new devices to at91sam9_devs table.

at91_machdep.c & at at91sam9_machdep.c:

    * Automatic chip type determination.
    * Remove compile time chip dependencies.
    * Eliminate separate at91sam9_machdep.c file.

at91_pmc.c:

    * Corrected support for all of the sam926? and sam9g20 chips.
    * Remove compile time chip dependencies.

My apologies to Greg for taking so long to take care of it.
2010-10-06 22:25:21 +00:00

58 lines
1.6 KiB
ArmAsm

#include <machine/asm.h>
#include <arm/at91/at91_rstreg.h>
#include <arm/at91/at91sam9g20reg.h>
__FBSDID("$FreeBSD$");
#define SDRAM_TR (AT91SAM9G20_BASE + \
AT91SAM9G20_SDRAMC_BASE + AT91SAM9G20_SDRAMC_TR)
#define SDRAM_LPR (AT91SAM9G20_BASE + \
AT91SAM9G20_SDRAMC_BASE + AT91SAM9G20_SDRAMC_LPR)
#define RSTC_RCR (AT91SAM9G20_BASE + \
AT91SAM9G20_RSTC_BASE + RST_CR)
/*
* From AT91SAM9G20 Datasheet errata 44:3.5:
*
* When User Reset occurs durring SDRAM read acces, eh SDRAM clock is turned
* off while data are ready to be read on the data bus. The SDRAM maintains
* the data until the clock restarts.
*
* If the User reset is programed to assert a general reset, the data
* If the User reset is programed to assert a general reset, the data
* maintained by the SDRAM leads to a data bus conflict and adversly affects
* the boot memories connected to the EBI:
* + NAND Flash boot functionality, if the system boots out of internal ROM.
* + NOR Flash boot, if the system boots on an external memory connected to
* the EBI CS0.
*
* Assembly code is mandatory for the following sequnce as ARM
* instructions need to be piplined.
*
*/
ENTRY(cpu_reset_sam9g20)
/* Disable IRQs */
mrs r0, cpsr
orr r0, r0, #0x80
msr cpsr_c, r0
/* Change Refresh to block all data access */
ldr r0, =SDRAM_TR
ldr r1, =1
str r1, [r0]
/* Prepare power down command */
ldr r0, =SDRAM_LPR
ldr r1, =2
/* Prepare proc_reset and periph reset */
ldr r2, =RSTC_RCR
ldr r3, =0xA5000005
/* perform power down command */
str r1, [r0]
/* Perfom proc_reset and periph reset (in the ARM pipeline) */
str r3, [r2]