/*
 *  VAS_EBOOT  --  GRand Unified Bootloader
 *  Copyright (C) 2009  Free Software Foundation, Inc.
 *
 *  VAS_EBOOT is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  VAS_EBOOT is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with VAS_EBOOT.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <VasEBoot/mm.h>
#include <VasEBoot/misc.h>

#include <VasEBoot/types.h>
#include <VasEBoot/types.h>
#include <VasEBoot/err.h>
#include <VasEBoot/cache.h>

#include <VasEBoot/mips/relocator.h>
#include <VasEBoot/relocator_private.h>

/* Do we need mips64? */

extern VasEBoot_uint8_t VasEBoot_relocator_forward_start;
extern VasEBoot_uint8_t VasEBoot_relocator_forward_end;
extern VasEBoot_uint8_t VasEBoot_relocator_backward_start;
extern VasEBoot_uint8_t VasEBoot_relocator_backward_end;

#define REGW_SIZEOF (2 * sizeof (VasEBoot_uint32_t))
#define JUMP_SIZEOF (2 * sizeof (VasEBoot_uint32_t))

#define RELOCATOR_SRC_SIZEOF(x) (&VasEBoot_relocator_##x##_end \
				 - &VasEBoot_relocator_##x##_start)
#define RELOCATOR_SIZEOF(x)	(RELOCATOR_SRC_SIZEOF(x) \
				 + REGW_SIZEOF * 3)
VasEBoot_size_t VasEBoot_relocator_align = sizeof (VasEBoot_uint32_t);
VasEBoot_size_t VasEBoot_relocator_forward_size;
VasEBoot_size_t VasEBoot_relocator_backward_size;
VasEBoot_size_t VasEBoot_relocator_jumper_size = JUMP_SIZEOF + REGW_SIZEOF;
VasEBoot_size_t VasEBoot_relocator_preamble_size = 0;

void
VasEBoot_cpu_relocator_init (void)
{
  VasEBoot_relocator_forward_size = RELOCATOR_SIZEOF(forward);
  VasEBoot_relocator_backward_size = RELOCATOR_SIZEOF(backward);
}

void
VasEBoot_cpu_relocator_preamble (void *rels __attribute__ ((unused)))
{
}

static void
write_reg (int regn, VasEBoot_uint32_t val, void **target)
{
  /* lui $r, (val+0x8000).  */
  *(VasEBoot_uint32_t *) *target = ((0x3c00 | regn) << 16) | ((val + 0x8000) >> 16);
  *target = ((VasEBoot_uint32_t *) *target) + 1;
  /* addiu $r, $r, val. */
  *(VasEBoot_uint32_t *) *target = (((0x2400 | regn << 5 | regn) << 16)
				| (val & 0xffff));
  *target = ((VasEBoot_uint32_t *) *target) + 1;
}

static void
write_jump (int regn, void **target)
{
  /* j $r.  */
  *(VasEBoot_uint32_t *) *target = (regn<<21) | 0x8;
  *target = ((VasEBoot_uint32_t *) *target) + 1;
  /* nop.  */
  *(VasEBoot_uint32_t *) *target = 0;
  *target = ((VasEBoot_uint32_t *) *target) + 1;
}

void
VasEBoot_cpu_relocator_jumper (void *rels, VasEBoot_addr_t addr)
{
  write_reg (1, addr, &rels);
  write_jump (1, &rels);
}

void
VasEBoot_cpu_relocator_backward (void *ptr0, void *src, void *dest,
			     VasEBoot_size_t size)
{
  void *ptr = ptr0;
  write_reg (8, (VasEBoot_uint32_t) src, &ptr);
  write_reg (9, (VasEBoot_uint32_t) dest, &ptr);
  write_reg (10, (VasEBoot_uint32_t) size, &ptr);
  VasEBoot_memcpy (ptr, &VasEBoot_relocator_backward_start,
	       RELOCATOR_SRC_SIZEOF (backward));
}

void
VasEBoot_cpu_relocator_forward (void *ptr0, void *src, void *dest,
			     VasEBoot_size_t size)
{
  void *ptr = ptr0;
  write_reg (8, (VasEBoot_uint32_t) src, &ptr);
  write_reg (9, (VasEBoot_uint32_t) dest, &ptr);
  write_reg (10, (VasEBoot_uint32_t) size, &ptr);
  VasEBoot_memcpy (ptr, &VasEBoot_relocator_forward_start,
	       RELOCATOR_SRC_SIZEOF (forward));
}

VasEBoot_err_t
VasEBoot_relocator32_boot (struct VasEBoot_relocator *rel,
		       struct VasEBoot_relocator32_state state)
{
  VasEBoot_relocator_chunk_t ch;
  void *ptr;
  VasEBoot_err_t err;
  void *relst;
  VasEBoot_size_t relsize;
  VasEBoot_size_t stateset_size = 31 * REGW_SIZEOF + JUMP_SIZEOF;
  unsigned i;
  VasEBoot_addr_t vtarget;

  err = VasEBoot_relocator_alloc_chunk_align (rel, &ch, 0, UP_TO_TOP32 (stateset_size),
					  stateset_size, sizeof (VasEBoot_uint32_t),
					  VAS_EBOOT_RELOCATOR_PREFERENCE_NONE, 0);
  if (err)
    return err;

  ptr = get_virtual_current_address (ch);
  for (i = 1; i < 32; i++)
    write_reg (i, state.gpr[i], &ptr);
  write_jump (state.jumpreg, &ptr);

  vtarget = (VasEBoot_addr_t) VasEBoot_map_memory (get_physical_target_address (ch),
					   stateset_size);

  err = VasEBoot_relocator_prepare_relocs (rel, vtarget, &relst, &relsize);
  if (err)
    return err;

  VasEBoot_arch_sync_caches ((void *) relst, relsize);

  ((void (*) (void)) relst) ();

  /* Not reached.  */
  return VAS_EBOOT_ERR_NONE;
}