S3C6410 u-boot源碼分析之cup_init.S

1、

#include <s3c6410.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

strr1, [r0]

下圖的黃色部分表明這出設置的作用，但我不明白，為何要設為0xd，要實現這個目標

@ Xm0CSn2 = NFCON CS0, Xm0CSn3 = NFCON CS1，好像與此處設計無關？

注：

• Memory port 0 is shared by using EBI (External Bus Interface).
• Memory port 1 is used only by DMC1.

• EBI module supports the share of pad interface used by 5 memory controllers (SROMC, two OneNANDCs,
CFCON, and NFCON).

SHARING CHIP SELECT FOR MEMORYPORT 0

The decision of which memory controller owns specific memory bank is decided both by following three
factors.
• Booting mode
• MP0_CS_CFG regsiter residing in System Controller
• XSELNAND input port value

2、

ldrr0, =ELFIN_DMC1_BASE@DMC1 base address 0x7e001000

只讀寄存器。

3、

ldr r1, =0x04
str r1, [r0, #INDEX_DMC_MEMC_CMD]

#define INDEX_DMC_MEMC_CMD (0x04)

看到下面的圖，應該知道為什麼了吧？

配置為：Configure模式

4、

其中有兩個寄存器沒賦值，如下所示：

下面那個可能采用的是默認值。而上面的是只寫寄存器，可能不需要賦值。