/*
   Boot.S: boot loader for Siemens DVB-S card
  
   Copyright (C) 2001 Convergence integrated media GmbH 
	              Written by Ralph Metzler
		                 <rjkm@convergence.de>
   Copyright (C) 2006 Matthieu CASTET <castet.mattheiu@free.fr>
 
   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