arch/arm-raspi/boot/vc_mb.c

   1 /*
   2     Copyright © 2013-2015, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: VideoCore mailbox support routines
   6     Lang: english
   7 */
   8
   9 #include <hardware/bcm283x.h>
  10 #include <hardware/videocore.h>
  11
  12 volatile unsigned int *vcmb_read(void *mb, unsigned int chan)
  13 {
  14     unsigned int try = 0x2000000;
  15     unsigned int msg;
  16
  17     if (chan <= VCMB_CHAN_MAX)
  18     {
  19         while(1)
  20         {
  21             while ((*((volatile unsigned int *)(mb + VCMB_STATUS)) & VCMB_STATUS_READREADY) != 0)
  22             {
  23                 asm volatile ("mcr p15, #0, %[r], c7, c14, #0" : : [r] "r" (0) );
  24
  25                 if(try-- == 0)
  26                 {
  27                     break;
  28                 }
  29             }
  30             asm volatile ("mcr p15, #0, %[r], c7, c10, #5" : : [r] "r" (0) );
  31
  32             msg = *((volatile unsigned int *)(mb + VCMB_READ));
  33
  34             asm volatile ("mcr p15, #0, %[r], c7, c10, #5" : : [r] "r" (0) );
  35
  36             if ((msg & VCMB_CHAN_MASK) == chan)
  37                 return (volatile unsigned int *)(msg & ~VCMB_CHAN_MASK);
  38         }
  39     }
  40     return (volatile unsigned int *)-1;
  41 }
  42
  43 void vcmb_write(void *mb, unsigned int chan, void *msg)
  44 {
  45     if ((((unsigned int)msg & VCMB_CHAN_MASK) == 0) && (chan <= VCMB_CHAN_MAX))
  46     {
  47         while ((*((volatile unsigned int *)(mb + VCMB_STATUS)) & VCMB_STATUS_WRITEREADY) != 0)
  48         {
  49             asm volatile ("mcr p15, #0, %[r], c7, c14, #0" : : [r] "r" (0) );
  50         }
  51
  52         asm volatile ("mcr p15, #0, %[r], c7, c10, #5" : : [r] "r" (0) );
  53
  54         *((volatile unsigned int *)(mb + VCMB_WRITE)) = ((unsigned int)msg | chan);
  55     }
  56 }