// Bootstream generator for Buildwin firmware loader
//
// (c) 2011, <hackfin@section5.ch>
//
//

#include "dpf.h"
#include "usbuser.h"            // our user defined flash commands
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdint.h>

// Jump offsets for USB command:
#define JMP_LOAD     0x0dae
#define JMP_SPILIB   0x11bf
#define JMP_USER     0x1000

#define PAGESIZE 256
#define BUFSIZE (64 - 6)
#define PKTSIZE (64 - 7)

typedef struct
{
  unsigned char len;
  unsigned char chk;
  unsigned char jmp[2];
  union
  {
    // Structures for various backends
    // The default memory loader:
    struct
    {
      unsigned char offset[2];  // XDATA memory dest address
      unsigned char buf[BUFSIZE]; // Binary data to write
    } loader;
    struct
    {
      unsigned char opcode;     // SPI operation opcode
      unsigned char wnum;       // Number of bytes to send (Host -> DPF)
      unsigned char rnum;       // Number of bytes to recv (DPF -> Host)
      unsigned char seq[PKTSIZE]; // SPI cmd sequence
    } spi;
  } u;
} UsbMsg;

#define OPCODE_SPISEL  0x01     // assert SELECT
#define OPCODE_CRYPT0  0x02
#define OPCODE_CRYPT1  0x04
#define OPCODE_SPIDES  0x10     // assert DESELECT

int
validate (UsbMsg * msg)
{
  unsigned short c = 0;
  unsigned char *b = (unsigned char *) msg;
  unsigned short l = msg->len;

  if (l < 6 || l > 64)
    return -1;

  while (l--)
    {
      c += *b++;
    }

  msg->chk -= c;

  return 0;
}

void
hexdump (unsigned char *buf, unsigned long n)
{
  int i = 0;
  int c = 0;

  while (i < n)
    {
      printf ("%02x ", buf[i]);
      c++;
      if (c == 16)
        {
          c = 0;
          printf ("\n");
        }
      i++;
    }
  if (c)
    printf ("\n");
}

int
transmit (DPFContext * dpf, UsbMsg * m)
{
  int error;
  unsigned char *s = (unsigned char *) m;
  // hexdump(s, m->len);
  error = usb_rawwrite (dpf->dev.udev, s, m->len);
  if (error < 0)
    {
      perror ("Writing to USB");
    }
  return error;
}

int
spilib_process (DPFContext * h, UsbMsg * umsg, unsigned char *out)
{
  int error;
  umsg->jmp[0] = JMP_SPILIB & 0xff;
  umsg->jmp[1] = JMP_SPILIB >> 8;
  umsg->len = 7 + umsg->u.spi.wnum;

  validate (umsg);
  error = transmit (h, umsg);
  if (umsg->u.spi.rnum > 0 && error >= 0)
    {
      error = usb_rawread (h->dev.udev, out, 64);
    }
  if (error < 0)
    perror ("Reading USB");
  else
    error = 0;
  return error;
}

int
go_hid (DPFContext * dpf, ADDR jmpoffset)
{
  UsbMsg umsg;
  umsg.jmp[0] = jmpoffset;
  umsg.jmp[1] = jmpoffset >> 8;
  umsg.len = 8;
  validate (&umsg);
  return transmit (dpf, &umsg);
}

int
load (DPFContext * dpf, FILE * f, uint16_t jmpoffset)
{
  int size;
  UsbMsg umsg;

  unsigned short offset = jmpoffset - 0x800;

  umsg.jmp[0] = JMP_LOAD & 0xff;
  umsg.jmp[1] = JMP_LOAD >> 8;
  umsg.chk = 0xce;
  size = fread (umsg.u.loader.buf, 1, BUFSIZE, f);
  if (size < 0)
    return size;

  while (size > 0)
    {
      umsg.u.loader.offset[0] = offset;
      umsg.u.loader.offset[1] = offset >> 8;
      umsg.len = sizeof (UsbMsg) - BUFSIZE + size;
      offset += size;
      validate (&umsg);
      transmit (dpf, &umsg);
      size = fread (umsg.u.loader.buf, 1, BUFSIZE, f);
    }

  // And jump into the code:
  if (jmpoffset != 0x0000)
    {
      go_hid (dpf, jmpoffset);
    }
  return size;
}

/* Flash stuff, HID wrapped */

static unsigned char s_rbuf[64];

static int
flash_probe_hid (DPFContext * h, unsigned char *id)
{
  int error;
  UsbMsg umsg;
  FILE *f;

  // First, load spilib.bin
  f = fopen ("spilib.bin", "rb");

  if (!f)
    {
      printf ("failed to open flash driver\n");
      return -1;
    }
  umsg.u.spi.opcode = OPCODE_SPISEL | OPCODE_SPIDES;

  error = load (h, f, 0x0000);  // Load, but do not execute
  fclose (f);
  usleep (500000);
  if (error == 0)
    {
      umsg.u.spi.wnum = 1;
      umsg.u.spi.rnum = 4;
      umsg.u.spi.seq[0] = SPM_RDID;
      error = spilib_process (h, &umsg, s_rbuf);
      id[0] = s_rbuf[0];
      id[1] = s_rbuf[1];
      id[2] = s_rbuf[2];
    }
  return error;
}

static int
flash_cmd_hid (DPFContext * h, int command, int cmdlen, ADDR addr)
{
  UsbMsg umsg;
  umsg.u.spi.opcode = OPCODE_SPISEL | OPCODE_SPIDES;
  umsg.u.spi.wnum = cmdlen;
  umsg.u.spi.rnum = 0;
  umsg.u.spi.seq[0] = command;
  umsg.u.spi.seq[1] = addr >> 16;
  umsg.u.spi.seq[2] = addr >> 8;
  umsg.u.spi.seq[3] = addr;

  return spilib_process (h, &umsg, 0);
}

int
flash_status_hid (DPFHANDLE h, uint8_t * status)
{
  int error;
  UsbMsg umsg;
  umsg.u.spi.opcode = OPCODE_SPISEL | OPCODE_SPIDES;
  umsg.u.spi.wnum = 1;
  umsg.u.spi.rnum = 1;
  umsg.u.spi.seq[0] = SPM_RDSR;

  error = spilib_process (h, &umsg, s_rbuf);
  *status = s_rbuf[0];
  return error;
}

static int
chunk_read (DPFContext * h, unsigned char *buf, ADDR offset, int len)
{
  int error;
  UsbMsg umsg;

  if (len > PKTSIZE)
    len = PKTSIZE;

  umsg.u.spi.opcode = OPCODE_SPISEL | OPCODE_SPIDES;
  umsg.u.spi.wnum = 4;
  umsg.u.spi.rnum = PKTSIZE;
  umsg.u.spi.seq[0] = SPM_READ;
  umsg.u.spi.seq[1] = offset >> 16;
  umsg.u.spi.seq[2] = offset >> 8;
  umsg.u.spi.seq[3] = offset;

  error = spilib_process (h, &umsg, buf);
  if (error < 0)
    return error;

  return len;
}


static int
flash_read_hid (DPFContext * h, unsigned char *buf, ADDR offset, int len)
{
  int n;

  while (len > 0)
    {
      n = chunk_read (h, buf, offset, len);
      if (n < 0)
        return n;
      len -= n;
      offset += n;
      buf += n;
    }
  return 0;
}

int
fill_spimsg (UsbMsg * umsg, const unsigned char *buf,
             unsigned short offset, int len)
{
  int n = PKTSIZE - offset;
  if (len > n)
    len = n;
  memcpy (&umsg->u.spi.seq[offset], buf, len);
  umsg->u.spi.wnum = offset + len;
  return len;
}

static int
flash_writechunk_hid (DPFContext * h,
                      const unsigned char *buf, ADDR offset, int len)
{
  UsbMsg umsg;
  int error;
  int n;

  if (len > PAGESIZE)
    len = PAGESIZE;

  umsg.u.spi.rnum = 0;
  umsg.u.spi.seq[0] = SPM_PP;
  umsg.u.spi.seq[1] = offset >> 16;
  umsg.u.spi.seq[2] = offset >> 8;
  umsg.u.spi.seq[3] = offset;

  n = fill_spimsg (&umsg, buf, 4, len);
  len -= n;
  buf += n;
  offset += n;

  umsg.u.spi.opcode = OPCODE_SPISEL;
  error = spilib_process (h, &umsg, 0);
  if (error < 0)
    return error;

  umsg.u.spi.opcode = 0;
  while (len > PKTSIZE)
    {
      n = fill_spimsg (&umsg, buf, 0, PKTSIZE);
      error = spilib_process (h, &umsg, 0);
      if (error < 0)
        return error;
      len -= n;
      buf += n;
      offset += n;
    }

  umsg.u.spi.opcode = OPCODE_SPIDES;
  fill_spimsg (&umsg, buf, 0, len);
  error = spilib_process (h, &umsg, 0);
  if (error < 0)
    return error;

  return PAGESIZE;
}

int
blk_write (DPFContext * h, ADDR dst, const unsigned char *src,
           unsigned short len)
{
  static UsbMsg umsg;

  if (len > BUFSIZE)
    len = BUFSIZE;

  umsg.jmp[0] = JMP_LOAD & 0xff;
  umsg.jmp[1] = JMP_LOAD >> 8;
  memcpy (umsg.u.loader.buf, src, len);
  umsg.u.loader.offset[0] = dst;
  umsg.u.loader.offset[1] = dst >> 8;
  umsg.len = sizeof (UsbMsg) - BUFSIZE + len;

  validate (&umsg);
  transmit (h, &umsg);
  return len;
}

int
mem_write_hid (DPFContext * h,
               ADDR dst, const unsigned char *src, unsigned short n)
{
  int len;

  while (n > 0)
    {
      len = blk_write (h, dst, src, n);
      n -= len;
      src += len;
      dst += len;
    }
  return n;
}


AccessMethods hid_methods =
{
.mem_read = NULL,.mem_write = mem_write_hid,.go = go_hid,.bootstrap =
    NULL,.flash_probe = flash_probe_hid,.flash_cmd =
    flash_cmd_hid,.flash_status = flash_status_hid,.flash_read =
    flash_read_hid,.flash_writechunk = flash_writechunk_hid,.flash_lock =
    NULL,};


#ifdef TEST
int
main (int argc, char **argv)
{
  FILE *f;
  int error;
  DPFHANDLE dpf;
  uint16_t startaddr = 0x1000;

  if (argc >= 2)
    {

      f = fopen (argv[1], "rb");

      if (!f)
        {
          printf ("failed to open file\n");
          return -1;
        }
      if (argc == 3)
        {
          startaddr = strtol (argv[2], NULL, 16);
          printf ("Starting at %04x\n", startaddr);
        }

      error = dpf_open ("usb0", &dpf);
      if (error < 0)
        {
          printf ("Failed to open DPF\n");
          return error;
        }
      if (dpf->mode == MODE_USBHID)
        {
          error = load (dpf, f, startaddr);
        }
      else
        {
          printf ("Not in BOOTLOAD mode! Press Reset and hold MENU\n");
        }
      dpf_close (dpf);
    }
  else
    {
      printf ("Needs boot image argument\n");
    }

  if (error < 0)
    {
      printf ("Error\n");
    }
  return error;
}
#endif