linux/firmware/av7110/Boot.S
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   1/*
   2   Boot.S: boot loader for Siemens DVB-S card
   3
   4   Copyright (C) 2001 Convergence integrated media GmbH
   5                      Written by Ralph Metzler
   6                                 <rjkm@convergence.de>
   7   Copyright (C) 2006 Matthieu CASTET <castet.mattheiu@free.fr>
   8
   9   This program is free software; you can redistribute it and/or
  10   modify it under the terms of the GNU General Public License
  11   as published by the Free Software Foundation; either version 2
  12   of the License, or (at your option) any later version.
  13
  14   This program is distributed in the hope that it will be useful,
  15   but WITHOUT ANY WARRANTY; without even the implied warranty of
  16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17   GNU General Public License for more details.
  18
  19   You should have received a copy of the GNU General Public License
  20   along with this program; if not, write to the Free Software
  21   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA.
  22
  23*/
  24
  25/*
  26        check AV711x_3_1.pdf for some hardware infos
  27        build it with :
  28        $ cc -mbig-endian -c Boot.S
  29        $ ld -Ttext 0x2c000000 -EB -o Boot Boot.o
  30        $ objcopy -Obinary Boot
  31*/
  32
  33        .text
  34        .align
  35        .globl _start
  36_start:
  37        b reset                 // reset vector
  38        movs  pc, r14           // undefined
  39        subs  pc, r14, #4       // SWI
  40        subs  pc, r14, #4       // prefetch abort
  41        subs  pc, r14, #8       // data abort
  42        subs  pc, r14, #4       // reserved
  43        subs  pc, r14, #4       // IRQ
  44        subs  pc, r14, #4       // FIQ
  45
  46        .word tbl               // table needed by firmware ROM
  47tbl:    .word (endtbl - tbl)
  48        .word 0
  49        .word conf
  50endtbl: .word 0
  51conf:   .word 0xa5a55a5a
  52        .word 0x001f1555
  53        .word 0x00000009
  54
  55reset:  ldr     r13, buffer
  56        ldr     r4, flag
  57        mov     r0, #0
  58        str     r0, [r4]
  59        str     r0, [r4, #4]
  60
  61        ldr             r1, wait_address
  62        ldr             r2, flag_address
  63        ldr             r3, sram
  64
  65copycode: // copy the code HW Sram
  66        ldmia   r1!, {r5-r12}
  67        stmia   r3!, {r5-r12}
  68        cmp             r1, r2
  69        ble     copycode
  70        ldr             pc, sram // jump to the copied code
  71
  72wait:   ldrh    r1, [r4]        // wait for flag!=0
  73        cmp     r1, #0
  74        beq     wait
  75
  76        mov     r1, r13         // buffer address
  77        ldr     r3, [r4,#4]     // destaddr
  78
  79        ldrh    r2, [r4,#2]     // get segment length
  80        add     r2, r2, #63     // round length to next 64 bytes
  81        movs    r2, r2, lsr #6  // and divide by 64
  82        moveq   r0, #2          // if 0, set flag to 2, else signal
  83        strh    r0, [r4]        // that buffer is accepted by setting to 0
  84        beq wait
  85        
  86copyloop:
  87        ldmia   r1!, {r5-r12}
  88        stmia   r3!, {r5-r12}
  89        ldmia   r1!, {r5-r12}
  90        stmia   r3!, {r5-r12}
  91        subs    r2, r2, #1
  92        bne     copyloop
  93
  94        eor     r13, r13, #0x1400    // switch to other buffer
  95        b       wait
  96
  97// flag is stored at 0x2c0003f8, length at 0x2c0003fa,
  98// destaddr at 0x2c0003fc
  99
 100flag:   .word   0x2c0003f8
 101
 102
 103// buffer 1 is at 0x2c000400, buffer 2 at 0x2c001000
 104
 105buffer: .word   0x2c000400
 106
 107sram: .word   0x9e000800
 108wait_address: .word   wait
 109flag_address: .word   flag
 110
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