@ new version for dzo bootloader inclusion

.globl _start
.equ _start,0x0

@ r3 is #0
@ r2 is #06d0 (for phys_setup)
@ r13 holds temp values for mcr/mrc
@ r13 holds temp values for mcr/mrc

mov r3, #0

.macro phys_setup
	@ r3 is 0
	mcr p15, 0, r3, c7, c10, 5
	mrc p15, 0, r1, c15, c2, 0	@ get old remap registers
	mov r2, #0x6d0
	add r2, #0xb
	mcr p15, 0, r2, c15, c2, 0	@ set all data access to be device-nonshared
.endm

.macro phys_restore
	mcr p15, 0, r1, c15, c2, 0	@ restore
.endm

@ make sure we are in svc32 mode
mrs r13,cpsr
bic r13,r13,#0x1f
orr r13,r13,#0xd3
msr cpsr,r13

@ clear the screen to green and start dma
@ code from dzo htc-vogue early printk

#define DOUBLERGB_GREEN 0x7e007e0
@ physical page of fb

@ htc values from ce, we can try the dzo values instead
@#define HTC_FB_PHYS 0x16800000
@#define HTC_FB_PHYS_END 0x16896000
#define HTC_FB_PHYS 0x00700000
#define HTC_FB_PHYS_END 0x00796000

@ 0xaa200000 r7 +
#define INTSTATUS 0x24
#define INTCLEAR 0x28
#define VSYNC 0x8c

@ offset from mdp control regs phys, use {read_write}_d_mdp_control
@ 0xaa210000 r8 +
#define BYPASS33 0x184
#define BYPASS34 0x188
#define BYPASS35 0x18c
#define BYPASS37 0x194
#define BYPASS40 0x1a0
#define BYPASS41 0x1a4

#define DMACONFIG 0x180
#define DMASTART 0x44

.text
.align 2	@ two bits must be zero, therefore align on word boundaries
_start:

@ setup registers
mov r5,#HTC_FB_PHYS
ldr r6,=HTC_FB_PHYS_END
ldr r7, = 0xaa200000	@ mdp registers
ldr r8, = 0xaa210000	@ mdp control registers

ldr r4,		=DOUBLERGB_GREEN	@ green
ldr r9,		=0x14000f0
ldr r10,	=0x000001e0
ldr r11,	=0x566600c3
ldr r12,	=0x0032616a
@ r13 is scratch

@ we can enter phys_setup at this point
@ eliminate any memory access after this point before clearing screen again

clearscreenloop:
	str r4,[r5]
	add r5, r5, #4
	cmp r5,r6
	ble clearscreenloop

@ clear two pixels
str r4,[r5]

phys_setup
@ no memory access after this

@ clear interrupt
waitforint:
	ldr r4, [r7, #INTSTATUS]	@ 0xaa200000 r7 +
	cmp r4, #0
	bne waitforint
	str r4, [r7, #INTCLEAR]		@ 0xaa200000 r7 +

@ldr r9, =0x14000f0
str r9, [r8, #BYPASS33]		@ 0xaa210000 r8 +

@ r5 is already HTC_FB_PHYS just use it
str r5, [r8, #BYPASS34]		@ 0xaa200000 r8 +


@ldr r10, =0x000001e0
str r10, [r8, #BYPASS35]	@ 0xaa210000 r8 +

@ r3 is 0
str r3, [r8, #BYPASS37]		@ 0xaa210000 r8 +
str r3, [r8, #BYPASS40]		@ 0xaa210000 r8 +

@ldr r11, =0x566600c3
str r11, [r8, #BYPASS41]	@ 0xaa21000 r8 +

@ keep updating the screen
dmaloop:

	@ldr r12, =0x0032616a
	str r12, [r6, #DMACONFIG]		@ 0xaa21000 r8 +

	@ r3 is 0
	str r3, [r7, #VSYNC]			@ 0xaa200000 r7 +
	str r3, [r8, #DMASTART]			@ 0xaa210000 r8 +

	@ r13 is scratch

	waitforint2:
		ldr r13, [r7, #INTSTATUS]	@ 0xaa200000 r7 +
		cmp r13, #0
		bne waitforint2

	@ clear interrupt
	waitforint3:
		phys_setup
		ldr r13, [r7, #INTSTATUS]	@ 0xaa200000 r7 +
		phys_restore
		cmp r13, #0
		beq waitforint3
	str r4, [r7, #INTCLEAR]			@ 0xaa20000 r7 +

phys_restore

@ draw a line (480 pixels)
@mov r5, #HTC_FB_PHYS
@ replacing HTC_FB_PHYS_END we are only clearing one line
mov r6, #240		@ one line, 240 words is 480 pixels
ldr r4, =DOUBLERGB_GREEN

lineloop:
	str r4,[r5,r6]		@ r6 is HTC_FB_PHYS
	subs r6,r6,#4
	cmp r6,#0
	bne lineloop

@ and update the screen
phys_setup

b dmaloop

.data