cpu_init.s

s3c6410的 Uboot 代码, 感兴趣的可以看看呀

#include <config.h>
#include <s3c6400.h>

	.globl mem_ctrl_asm_init
mem_ctrl_asm_init:
	ldr	r0, =ELFIN_MEM_SYS_CFG			@Memory sussystem address 0x7e00f120
	mov	r1, #0xd				@ Xm0CSn2 = NFCON CS0, Xm0CSn3 = NFCON CS1
	str	r1, [r0]
	
	ldr	r0, =ELFIN_DMC1_BASE			@DMC1 base address 0x7e001000 

	ldr	r1, =0x4
	str	r1, [r0, #INDEX_DMC_MEMC_CMD]

	ldr	r1, =DMC_DDR_REFRESH_PRD
	str	r1, [r0, #INDEX_DMC_REFRESH_PRD]

	ldr	r1, =DMC_DDR_CAS_LATENCY
	str	r1, [r0, #INDEX_DMC_CAS_LATENCY]

	ldr	r1, =DMC_DDR_t_DQSS
	str	r1, [r0, #INDEX_DMC_T_DQSS]

	ldr	r1, =DMC_DDR_t_MRD
	str	r1, [r0, #INDEX_DMC_T_MRD]

	ldr	r1, =DMC_DDR_t_RAS
	str	r1, [r0, #INDEX_DMC_T_RAS]

	ldr	r1, =DMC_DDR_t_RC
	str	r1, [r0, #INDEX_DMC_T_RC]

	ldr	r1, =DMC_DDR_t_RCD
	ldr	r2, =DMC_DDR_schedule_RCD
	orr	r1, r1, r2
	str	r1, [r0, #INDEX_DMC_T_RCD]

	ldr	r1, =DMC_DDR_t_RFC
	ldr	r2, =DMC_DDR_schedule_RFC
	orr	r1, r1, r2
	str	r1, [r0, #INDEX_DMC_T_RFC]

	ldr	r1, =DMC_DDR_t_RP
	ldr	r2, =DMC_DDR_schedule_RP
	orr	r1, r1, r2
	str	r1, [r0, #INDEX_DMC_T_RP]

	ldr	r1, =DMC_DDR_t_RRD
	str	r1, [r0, #INDEX_DMC_T_RRD]

	ldr	r1, =DMC_DDR_t_WR
	str	r1, [r0, #INDEX_DMC_T_WR]

	ldr	r1, =DMC_DDR_t_WTR
	str	r1, [r0, #INDEX_DMC_T_WTR]

	ldr	r1, =DMC_DDR_t_XP
	str	r1, [r0, #INDEX_DMC_T_XP]

	ldr	r1, =DMC_DDR_t_XSR
	str	r1, [r0, #INDEX_DMC_T_XSR]

	ldr	r1, =DMC_DDR_t_ESR
	str	r1, [r0, #INDEX_DMC_T_ESR]

	ldr	r1, =DMC1_MEM_CFG
	str	r1, [r0, #INDEX_DMC_MEMORY_CFG]

	ldr	r1, =DMC1_MEM_CFG2
	str	r1, [r0, #INDEX_DMC_MEMORY_CFG2]

	ldr	r1, =DMC1_CHIP0_CFG
	str	r1, [r0, #INDEX_DMC_CHIP_0_CFG]
	
	ldr	r1, =DMC_DDR_32_CFG
	str	r1, [r0, #INDEX_DMC_USER_CONFIG]

	@DMC0 DDR Chip 0 configuration direct command reg
	ldr	r1, =DMC_NOP0
	str	r1, [r0, #INDEX_DMC_DIRECT_CMD]

	@Precharge All
	ldr	r1, =DMC_PA0
	str	r1, [r0, #INDEX_DMC_DIRECT_CMD]

	@Auto Refresh	2 time
	ldr	r1, =DMC_AR0
	str	r1, [r0, #INDEX_DMC_DIRECT_CMD]
	str	r1, [r0, #INDEX_DMC_DIRECT_CMD]

	@MRS 
	ldr	r1, =DMC_mDDR_EMR0	
	str	r1, [r0, #INDEX_DMC_DIRECT_CMD]
	
	@Mode Reg
	ldr	r1, =DMC_mDDR_MR0
	str	r1, [r0, #INDEX_DMC_DIRECT_CMD]

	@Enable DMC1
	mov	r1, #0x0
	str	r1, [r0, #INDEX_DMC_MEMC_CMD]

check_dmc1_ready:
	ldr	r1, [r0, #INDEX_DMC_MEMC_STATUS]
	mov	r2, #0x3
	and	r1, r1, r2
	cmp	r1, #0x1
	bne	check_dmc1_ready
	nop
	mov	pc, lr	
	

/* Below code is for ARM926EJS and ARM1026EJS */
	.globl cleanDCache
cleanDCache:
	mrc	p15, 0, pc, c7, c10, 3	/* test/clean D-Cache */
	bne	cleanDCache
	mov	pc, lr

	.globl cleanFlushDCache
cleanFlushDCache:
	mrc	p15, 0, pc, c7, c14, 3	/* test/cleanflush D-Cache */
	bne	cleanFlushDCache
	mov	pc, lr

	.globl cleanFlushCache
cleanFlushCache:
	mrc	p15, 0, pc, c7, c14, 3	/* test/cleanflush D-Cache */
	bne	cleanFlushCache
	mcr	p15, 0, r0, c7, c5, 0	/* flush I-Cache */
	mov	pc, lr

	.ltorg