/*
 * Copyright (C) 2018 bzt (bztsrc@github)
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy,
 * modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 */

#include <gpio.h>
#include <mbox.h>

/* mailbox message buffer */
volatile unsigned int  __attribute__((aligned(16))) mbox[36];

#define VIDEOCORE_MBOX  (MMIO_BASE+0x0000B880)
#define MBOX_READ       ((volatile unsigned int*)(VIDEOCORE_MBOX+0x0))
#define MBOX_POLL       ((volatile unsigned int*)(VIDEOCORE_MBOX+0x10))
#define MBOX_SENDER     ((volatile unsigned int*)(VIDEOCORE_MBOX+0x14))
#define MBOX_STATUS     ((volatile unsigned int*)(VIDEOCORE_MBOX+0x18))
#define MBOX_CONFIG     ((volatile unsigned int*)(VIDEOCORE_MBOX+0x1C))
#define MBOX_WRITE      ((volatile unsigned int*)(VIDEOCORE_MBOX+0x20))
#define MBOX_RESPONSE   0x80000000
#define MBOX_FULL       0x80000000
#define MBOX_EMPTY      0x40000000

#define MAILBOX_BASE    MMIO_BASE + 0xb880

#define REQUEST_SUCCEED     0x80000000
#define REQUEST_FAILED      0x80000001
#define TAG_MBOX_REQUEST    0x00000000

/**
 * Make a mailbox call. Returns 0 on failure, non-zero on success
 */
int mbox_call(unsigned char ch)
{
  unsigned int r = (((unsigned int)((unsigned long)&mbox)&~0xF) | (ch&0xF));
  /* wait until we can write to the mailbox */
  do{asm volatile("nop");}while(*MBOX_STATUS & MBOX_FULL);
  /* write the address of our message to the mailbox with channel identifier */
  *MBOX_WRITE = r;
  /* now wait for the response */
  while(1) {
    /* is there a response? */
    do{asm volatile("nop");}while(*MBOX_STATUS & MBOX_EMPTY);
    /* is it a response to our message? */
    if(r == *MBOX_READ)
      /* is it a valid successful response? */
      return mbox[1]==MBOX_RESPONSE;
  }
  return 0;
}

unsigned int get_board_revision(void)
{
  mbox[0] = 36 * 4;
  mbox[1] = MBOX_REQUEST;

  // tags
  mbox[2] = MBOX_TAG_BOARD_REVISION;
  mbox[3] = 4;
  mbox[4] = TAG_MBOX_REQUEST;
  mbox[5] = 0; // value buffer

  mbox[6] = MBOX_TAG_LAST;

  mbox_call(MBOX_CH_PROP);

  return mbox[5];
}

unsigned int get_memory_base_addr(void)
{
  mbox[0] = 36 * 4;
  mbox[1] = MBOX_REQUEST;

  // tags
  mbox[2] = MBOX_TAG_ARM_MEMORY;
  mbox[3] = 8;
  mbox[4] = 8;
  mbox[5] = 0;
  mbox[6] = 0;

  mbox[7] = MBOX_TAG_LAST;

  mbox_call(MBOX_CH_PROP);

  return mbox[5];
}

unsigned int get_memory_size(void)
{
  mbox[0] = 36 * 4;
  mbox[1] = MBOX_REQUEST;

  // tags
  mbox[2] = MBOX_TAG_ARM_MEMORY;
  mbox[3] = 8;
  mbox[4] = 8;
  mbox[5] = 0;
  mbox[6] = 0;

  mbox[7] = MBOX_TAG_LAST;

  mbox_call(MBOX_CH_PROP);

  return mbox[6];
}