/*
Boot.S: boot loader for Siemens DVB-S card

Copyright (C) 2001 Convergence integrated media GmbH
Written by Ralph Metzler
<[email protected]>
Copyright (C) 2006 Matthieu CASTET <[email protected]>

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

*/

/*
check AV711x_3_1.pdf for some hardware infos
build it with :
$ cc -mbig-endian -c Boot.S
$ ld -Ttext 0x2c000000 -EB -o Boot Boot.o
$ objcopy -Obinary Boot
*/

.text
.align
.globl _start
_start:
b reset // reset vector
movs pc, r14 // undefined
subs pc, r14, #4 // SWI
subs pc, r14, #4 // prefetch abort
subs pc, r14, #8 // data abort
subs pc, r14, #4 // reserved
subs pc, r14, #4 // IRQ
subs pc, r14, #4 // FIQ

.word tbl // table needed by firmware ROM
tbl: .word (endtbl - tbl)
.word 0
.word conf
endtbl: .word 0
conf: .word 0xa5a55a5a
.word 0x001f1555
.word 0x00000009

reset: ldr r13, buffer
ldr r4, flag
mov r0, #0
str r0, [r4]
str r0, [r4, #4]

ldr r1, wait_address
ldr r2, flag_address
ldr r3, sram

copycode: // copy the code HW Sram
ldmia r1!, {r5-r12}
stmia r3!, {r5-r12}
cmp r1, r2
ble copycode
ldr pc, sram // jump to the copied code

wait: ldrh r1, [r4] // wait for flag!=0
cmp r1, #0
beq wait

mov r1, r13 // buffer address
ldr r3, [r4,#4] // destaddr

ldrh r2, [r4,#2] // get segment length
add r2, r2, #63 // round length to next 64 bytes
movs r2, r2, lsr #6 // and divide by 64
moveq r0, #2 // if 0, set flag to 2, else signal
strh r0, [r4] // that buffer is accepted by setting to 0
beq wait

copyloop:
ldmia r1!, {r5-r12}
stmia r3!, {r5-r12}
ldmia r1!, {r5-r12}
stmia r3!, {r5-r12}
subs r2, r2, #1
bne copyloop

eor r13, r13, #0x1400 // switch to other buffer
b wait

// flag is stored at 0x2c0003f8, length at 0x2c0003fa,
// destaddr at 0x2c0003fc

flag: .word 0x2c0003f8


// buffer 1 is at 0x2c000400, buffer 2 at 0x2c001000

buffer: .word 0x2c000400

sram: .word 0x9e000800
wait_address: .word wait
flag_address: .word flag