ex35_gprs_startup.s

GPRS模组资料包含DEMO

.extern _start
.section .hardware_init,"ax",@progbits

.global _hardware_init
.ent _hardware_init
_hardware_init:
	////////////////////////////////////////////////////
	// disable write back data cache
		mfcr r5, cr4
		nop
		li r7, 0x80
		andri r6, r5, 0x80
		cmp.c r7, r6				//	Check under WB mode?
		bne under_wt
		nop
under_wb:
		la r7, tgl_wb
		cache 0x1f, [r7, 0]			//	force write out dirty entry and set invalid
		nop
		nop
		nop
tgl_wb:
		cache 0x1d, [r7, 0]			//	toggle write-back function
		nop
under_wt:							//	Processor is under write-through mode

	//Interrupt enable
		li r4, 0x1
		mtcr r4, cr0
		nop
		nop
		nop
		nop
		nop
	//change exception vector base to 0xa0000000
		li r4, 0xa0000000
		mtcr r4, cr3

	//LDM enable
		li r5,  0xa1000000			//	The start address of data segment will move to LDM
		cache 0xb, [r5,0]			//	The size of data segment will move to LDM(8k byte)
		mfcr r11, cr4
		ori r11, 0x8				//	Enable LDM bit(bit 3) of CCR4
		bitset.c r11,r11,16			//	Enable low power mode
		mtcr r11, cr4				//	Enable LDM bit(bit 3) of CCR4 (W-Sttage)
		nop
		nop
		nop
		nop
		nop
		nop
		la r0,_stack
	/////////////////////////////////////////////////////
	// Enable BIU Write buffer
		la r4, biu_wben
biu_wben:
		cache 0x1b, [r4, 0]
		j _start

.end _hardware_init