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/* Parts of target interface that deal with accessing memory and memory-like

   objects.

   Copyright (C) 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.

   This file is part of GDB.

   This program 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.

   This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"

#include "vec.h"

#include "target.h"

#include "memory-map.h"

#include "gdb_assert.h"

#include <stdio.h>

#include <sys/time.h>

static int

compare_block_starting_address (const void *a, const void *b)

{

  const struct memory_write_request *a_req = a;

  const struct memory_write_request *b_req = b;

  if (a_req->begin < b_req->begin)

    return -1;

  else if (a_req->begin == b_req->begin)

    return 0;

  else

    return 1;

}

/* Adds to RESULT all memory write requests from BLOCK that are

   in [BEGIN, END) range.

   If any memory request is only partially in the specified range,

   that part of the memory request will be added.  */

static void

claim_memory (VEC(memory_write_request_s) *blocks,

              VEC(memory_write_request_s) **result,

              ULONGEST begin,

              ULONGEST end)

{

  int i;

  ULONGEST claimed_begin;

  ULONGEST claimed_end;

  struct memory_write_request *r;

  for (i = 0; VEC_iterate (memory_write_request_s, blocks, i, r); ++i)

    {

      /* If the request doesn't overlap [BEGIN, END), skip it.  We

         must handle END == 0 meaning the top of memory; we don't yet

         check for R->end == 0, which would also mean the top of

         memory, but there's an assertion in

         target_write_memory_blocks which checks for that.  */

      if (begin >= r->end)

        continue;

      if (end != 0 && end <= r->begin)

        continue;

      claimed_begin = max (begin, r->begin);

      if (end == 0)

        claimed_end = r->end;

      else

        claimed_end = min (end, r->end);

      if (claimed_begin == r->begin && claimed_end == r->end)

        VEC_safe_push (memory_write_request_s, *result, r);

      else

        {

          struct memory_write_request *n =

            VEC_safe_push (memory_write_request_s, *result, NULL);

          *n = *r;

          n->begin = claimed_begin;

          n->end = claimed_end;

          n->data += claimed_begin - r->begin;

        }

    }

}

/* Given a vector of struct memory_write_request objects in BLOCKS,

   add memory requests for flash memory into FLASH_BLOCKS, and for

   regular memory to REGULAR_BLOCKS.  */

static void

split_regular_and_flash_blocks (VEC(memory_write_request_s) *blocks,

                                VEC(memory_write_request_s) **regular_blocks,

                                VEC(memory_write_request_s) **flash_blocks)

{

  struct mem_region *region;

  CORE_ADDR cur_address;

  /* This implementation runs in O(length(regions)*length(blocks)) time.

     However, in most cases the number of blocks will be small, so this does

     not matter.

     Note also that it's extremely unlikely that a memory write request

     will span more than one memory region, however for safety we handle

     such situations.  */

  cur_address = 0;

  while (1)

    {

      VEC(memory_write_request_s) **r;

      region = lookup_mem_region (cur_address);

      r = region->attrib.mode == MEM_FLASH ? flash_blocks : regular_blocks;

      cur_address = region->hi;

      claim_memory (blocks, r, region->lo, region->hi);

      if (cur_address == 0)

        break;

    }

}

/* Given an ADDRESS, if BEGIN is non-NULL this function sets *BEGIN

   to the start of the flash block containing the address.  Similarly,

   if END is non-NULL *END will be set to the address one past the end

   of the block containing the address.  */

static void

block_boundaries (CORE_ADDR address, CORE_ADDR *begin, CORE_ADDR *end)

{

  struct mem_region *region;

  unsigned blocksize;

  region = lookup_mem_region (address);

  gdb_assert (region->attrib.mode == MEM_FLASH);

  blocksize = region->attrib.blocksize;

  if (begin)

    *begin = address / blocksize * blocksize;

  if (end)

    *end = (address + blocksize - 1) / blocksize * blocksize;

}

/* Given the list of memory requests to be WRITTEN, this function

   returns write requests covering each group of flash blocks which must

   be erased.  */

static VEC(memory_write_request_s) *

blocks_to_erase (VEC(memory_write_request_s) *written)

{

  unsigned i;

  struct memory_write_request *ptr;

  VEC(memory_write_request_s) *result = NULL;

  for (i = 0; VEC_iterate (memory_write_request_s, written, i, ptr); ++i)

    {

      CORE_ADDR begin, end;

      block_boundaries (ptr->begin, &begin, 0);

      block_boundaries (ptr->end - 1, 0, &end);

      if (!VEC_empty (memory_write_request_s, result)

          && VEC_last (memory_write_request_s, result)->end >= begin)

        {

          VEC_last (memory_write_request_s, result)->end = end;

        }

      else

        {

          struct memory_write_request *n =

            VEC_safe_push (memory_write_request_s, result, NULL);

          memset (n, 0, sizeof (struct memory_write_request));

          n->begin = begin;

          n->end = end;

        }

    }

  return result;

}

/* Given ERASED_BLOCKS, a list of blocks that will be erased with

   flash erase commands, and WRITTEN_BLOCKS, the list of memory

   addresses that will be written, compute the set of memory addresses

   that will be erased but not rewritten (e.g. padding within a block

   which is only partially filled by "load").  */

static VEC(memory_write_request_s) *

compute_garbled_blocks (VEC(memory_write_request_s) *erased_blocks,

                        VEC(memory_write_request_s) *written_blocks)

{

  VEC(memory_write_request_s) *result = NULL;

  unsigned i, j;

  unsigned je = VEC_length (memory_write_request_s, written_blocks);

  struct memory_write_request *erased_p;

  /* Look at each erased memory_write_request in turn, and

     see what part of it is subsequently written to.

     This implementation is O(length(erased) * length(written)).  If

     the lists are sorted at this point it could be rewritten more

     efficiently, but the complexity is not generally worthwhile.  */

  for (i = 0;

       VEC_iterate (memory_write_request_s, erased_blocks, i, erased_p);

       ++i)

    {

      /* Make a deep copy -- it will be modified inside the loop, but

         we don't want to modify original vector.  */

      struct memory_write_request erased = *erased_p;

      for (j = 0; j != je;)

        {

          struct memory_write_request *written

            = VEC_index (memory_write_request_s,

                         written_blocks, j);

          /* Now try various cases.  */

          /* If WRITTEN is fully to the left of ERASED, check the next

             written memory_write_request.  */

          if (written->end <= erased.begin)

            {

              ++j;

              continue;

            }

          /* If WRITTEN is fully to the right of ERASED, then ERASED

             is not written at all.  WRITTEN might affect other

             blocks.  */

          if (written->begin >= erased.end)

            {

              VEC_safe_push (memory_write_request_s, result, &erased);

              goto next_erased;

            }

          /* If all of ERASED is completely written, we can move on to

             the next erased region.  */

          if (written->begin <= erased.begin

              && written->end >= erased.end)

            {

              goto next_erased;

            }

          /* If there is an unwritten part at the beginning of ERASED,

             then we should record that part and try this inner loop

             again for the remainder.  */

          if (written->begin > erased.begin)

            {

              struct memory_write_request *n =

                VEC_safe_push (memory_write_request_s, result, NULL);

              memset (n, 0, sizeof (struct memory_write_request));

              n->begin = erased.begin;

              n->end = written->begin;

              erased.begin = written->begin;

              continue;

            }

          /* If there is an unwritten part at the end of ERASED, we

             forget about the part that was written to and wait to see

             if the next write request writes more of ERASED.  We can't

             push it yet.  */

          if (written->end < erased.end)

            {

              erased.begin = written->end;

              ++j;

              continue;

            }

        }

      /* If we ran out of write requests without doing anything about

         ERASED, then that means it's really erased.  */

      VEC_safe_push (memory_write_request_s, result, &erased);

    next_erased:

      ;

    }

  return result;

}

static void

cleanup_request_data (void *p)

{

  VEC(memory_write_request_s) **v = p;

  struct memory_write_request *r;

  int i;

  for (i = 0; VEC_iterate (memory_write_request_s, *v, i, r); ++i)

    xfree (r->data);

}

static void

cleanup_write_requests_vector (void *p)

{

  VEC(memory_write_request_s) **v = p;

  VEC_free (memory_write_request_s, *v);

}

int

target_write_memory_blocks (VEC(memory_write_request_s) *requests,

                            enum flash_preserve_mode preserve_flash_p,

                            void (*progress_cb) (ULONGEST, void *))

{

  struct cleanup *back_to = make_cleanup (null_cleanup, NULL);

  VEC(memory_write_request_s) *blocks = VEC_copy (memory_write_request_s,

                                                  requests);

  unsigned i;

  int err = 0;

  struct memory_write_request *r;

  VEC(memory_write_request_s) *regular = NULL;

  VEC(memory_write_request_s) *flash = NULL;

  VEC(memory_write_request_s) *erased, *garbled;

  /* END == 0 would represent wraparound: a write to the very last

     byte of the address space.  This file was not written with that

     possibility in mind.  This is fixable, but a lot of work for a

     rare problem; so for now, fail noisily here instead of obscurely

     later.  */

  for (i = 0; VEC_iterate (memory_write_request_s, requests, i, r); ++i)

    gdb_assert (r->end != 0);

  make_cleanup (cleanup_write_requests_vector, &blocks);

  /* Sort the blocks by their start address.  */

  qsort (VEC_address (memory_write_request_s, blocks),

         VEC_length (memory_write_request_s, blocks),

         sizeof (struct memory_write_request), compare_block_starting_address);

  /* Split blocks into list of regular memory blocks,

     and list of flash memory blocks. */

  make_cleanup (cleanup_write_requests_vector, &regular);

  make_cleanup (cleanup_write_requests_vector, &flash);

  split_regular_and_flash_blocks (blocks, &regular, &flash);

  /* If a variable is added to forbid flash write, even during "load",

     it should be checked here.  Similarly, if this function is used

     for other situations besides "load" in which writing to flash

     is undesirable, that should be checked here.  */

  /* Find flash blocks to erase.  */

  erased = blocks_to_erase (flash);

  make_cleanup (cleanup_write_requests_vector, &erased);

  /* Find what flash regions will be erased, and not overwritten; then

     either preserve or discard the old contents.  */

  garbled = compute_garbled_blocks (erased, flash);

  make_cleanup (cleanup_request_data, &garbled);

  make_cleanup (cleanup_write_requests_vector, &garbled);

  if (!VEC_empty (memory_write_request_s, garbled))

    {

      if (preserve_flash_p == flash_preserve)

        {

          struct memory_write_request *r;

          /* Read in regions that must be preserved and add them to

             the list of blocks we read.  */

          for (i = 0; VEC_iterate (memory_write_request_s, garbled, i, r); ++i)

            {

              gdb_assert (r->data == NULL);

              r->data = xmalloc (r->end - r->begin);

              err = target_read_memory (r->begin, r->data, r->end - r->begin);

              if (err != 0)

                goto out;

              VEC_safe_push (memory_write_request_s, flash, r);

            }

          qsort (VEC_address (memory_write_request_s, flash),

                 VEC_length (memory_write_request_s, flash),

                 sizeof (struct memory_write_request), compare_block_starting_address);

        }

    }

  /* We could coalesce adjacent memory blocks here, to reduce the

     number of write requests for small sections.  However, we would

     have to reallocate and copy the data pointers, which could be

     large; large sections are more common in loadable objects than

     large numbers of small sections (although the reverse can be true

     in object files).  So, we issue at least one write request per

     passed struct memory_write_request.  The remote stub will still

     have the opportunity to batch flash requests.  */

  /* Write regular blocks.  */

  for (i = 0; VEC_iterate (memory_write_request_s, regular, i, r); ++i)

    {

      LONGEST len;

      len = target_write_with_progress (current_target.beneath,

                                        TARGET_OBJECT_MEMORY, NULL,

                                        r->data, r->begin, r->end - r->begin,

                                        progress_cb, r->baton);

      if (len < (LONGEST) (r->end - r->begin))

        {

          /* Call error?  */

          err = -1;

          goto out;

        }

    }

  if (!VEC_empty (memory_write_request_s, erased))

    {

      /* Erase all pages.  */

      for (i = 0; VEC_iterate (memory_write_request_s, erased, i, r); ++i)

        target_flash_erase (r->begin, r->end - r->begin);

      /* Write flash data.  */

      for (i = 0; VEC_iterate (memory_write_request_s, flash, i, r); ++i)

        {

          LONGEST len;

          len = target_write_with_progress (&current_target,

                                            TARGET_OBJECT_FLASH, NULL,

                                            r->data, r->begin, r->end - r->begin,

                                            progress_cb, r->baton);

          if (len < (LONGEST) (r->end - r->begin))

            error (_("Error writing data to flash"));

        }

      target_flash_done ();

    }

 out:

  do_cleanups (back_to);

  return err;

}