target/linux/gemini/image/copy-kernel/copy-kernel.S

   1         // Arm assembly to copy the Gemini kernel on Storlink reference
   2         // designs and derived devices with the same flash layout and
   3         // boot loader.
   4         //
   5         // This will execute at 0x01600000
   6         //
   7         // Copies the kernel from two fragments (originally zImage
   8         // and initramdisk) to 0x00400000 making space for a kernel
   9         // image of up to 8 MB except for these 512 bytes used for
  10         // this bootstrap.
  11         //
  12         // 0x01600200 .. 0x017fffff -> 0x00400000 .. 0x005ffdff
  13         // 0x00800000 .. 0x00dfffff -> 0x005ffe00 .. 0x00bffdff
  14
  15         // Memory used for this bootstrap
  16         .equ BOOT_HEADROOM,     0x200
  17
  18         .global _start // Stand-alone assembly code
  19 _start:
  20         mov r1, #0x01600000
  21         mov r2, #0x00400000
  22         mov r3, #0x00200000
  23         add r1, r1, #BOOT_HEADROOM
  24         sub r3, r3, #BOOT_HEADROOM
  25 copyloop1:
  26         ldr r0, [r1]
  27         str r0, [r2]
  28         add r1, r1, #4
  29         add r2, r2, #4
  30         sub r3, r3, #4
  31         cmp r3, #0
  32         bne copyloop1
  33         mov r1, #0x00800000
  34         mov r3, #0x00600000
  35 copyloop2:
  36         ldr r0, [r1]
  37         str r0, [r2]
  38         add r1, r1, #4
  39         add r2, r2, #4
  40         sub r3, r3, #4
  41         cmp r3, #0
  42         bne copyloop2
  43         mov r0, #0x00400000
  44         // Let's go
  45         mov pc, r0