bootdm643.asm

ti的驱动程序例程

    
    .title "Flash bootup utility for DM642 EVM"
	.option D,T
	.length 102
	.width 140

COPY_TABLE .equ 0x90000400
EMIF_BASE .equ 0x01800000

	.sect ".boot_load"
	.global _boot

_boot: 
;************************************************************************
;* Debug Loop - Comment out B for Normal Operation
;************************************************************************

	zero B1
_myloop:  ;[!B1] B _myloop 
	nop 5
_myloopend: nop

;************************************************************************
;* Configure EMIF
;************************************************************************

	mvkl emif_values, a3 ; load pointer to emif values
	mvkh emif_values, a3

	mvkl EMIF_BASE, a4 ; load EMIF base address
	mvkh EMIF_BASE, a4

	mvkl 0x0009, b0 ; load number of registers to set
	mvkh 0x0000, b0

emif_loop:
	ldw *a3++, b5 ; load register value
	sub b0,1,b0 ; decrement counter
	nop 2
	[ b0] b emif_loop
	stw b5, *a4++ ; store register value
	nop 4 

;****************************************************************************
;* Copy code sections
;****************************************************************************
	mvkl COPY_TABLE, a3 ; load table pointer
	mvkh COPY_TABLE, a3

	ldw *a3++, b1 ; Load entry point

copy_section_top:
	ldw *a3++, b0 ; byte count 
	ldw *a3++, a4 ; ram start address
	nop 3

	[!b0] b copy_done ; have we copied all sections?
	nop 5

copy_loop:
	ldb *a3++,b5
	sub b0,1,b0 ; decrement counter
	[ b0] b copy_loop ; setup branch if not done
	[!b0] b copy_section_top
	zero a1
	[!b0] and 3,a3,a1
	stb b5,*a4++
	[!b0] and -4,a3,a5 ; round address up to next multiple of 4
	[ a1] add 4,a5,a3 ; round address up to next multiple of 4

;****************************************************************************
;* Jump to entry point
;****************************************************************************
copy_done:
	b .S2 b1
	nop 5

emif_values:
	.long 0x00052078 ; GBLCTL
	.long 0x73a28e01 ; CECTL1 (Flash/FPGA)
	.long 0xffffffd3 ; CECTL0 (SDRAM)
	.long 0x00000000 ; Reserved
	.long 0x22a28a22 ; CECTL2
	.long 0x22a28a22 ; CECTL3
	.long 0x57115000 ; SDCTL
	.long 0x0000081b ; SDTIM (refresh period)
	.long 0x001faf4d ; SDEXT