/*
   * Generic bounce buffer implementation
   *
   * Copyright (C) 2012 Marek Vasut <marex@denx.de>
   *

   * SPDX-License-Identifier:	GPL-2.0+

   */
  
  #include <common.h>
  #include <malloc.h>
  #include <errno.h>
  #include <bouncebuf.h>

  static int addr_aligned(struct bounce_buffer *state)

  {
  	const ulong align_mask = ARCH_DMA_MINALIGN - 1;
  
  	/* Check if start is aligned */

  	if ((ulong)state->user_buffer & align_mask) {
  		debug("Unaligned buffer address %p
  ", state->user_buffer);

  		return 0;
  	}

  	/* Check if length is aligned */
  	if (state->len != state->len_aligned) {
  		debug("Unaligned buffer length %d
  ", state->len);

  		return 0;
  	}
  
  	/* Aligned */
  	return 1;
  }

  int bounce_buffer_start(struct bounce_buffer *state, void *data,
  			size_t len, unsigned int flags)

  {

  	state->user_buffer = data;
  	state->bounce_buffer = data;
  	state->len = len;
  	state->len_aligned = roundup(len, ARCH_DMA_MINALIGN);
  	state->flags = flags;
  
  	if (!addr_aligned(state)) {
  		state->bounce_buffer = memalign(ARCH_DMA_MINALIGN,
  						state->len_aligned);
  		if (!state->bounce_buffer)
  			return -ENOMEM;
  
  		if (state->flags & GEN_BB_READ)
  			memcpy(state->bounce_buffer, state->user_buffer,
  				state->len);

  	}

  	/*
  	 * Flush data to RAM so DMA reads can pick it up,
  	 * and any CPU writebacks don't race with DMA writes
  	 */
  	flush_dcache_range((unsigned long)state->bounce_buffer,
  				(unsigned long)(state->bounce_buffer) +
  					state->len_aligned);

  
  	return 0;
  }

  int bounce_buffer_stop(struct bounce_buffer *state)

  {

  	if (state->flags & GEN_BB_WRITE) {
  		/* Invalidate cache so that CPU can see any newly DMA'd data */
  		invalidate_dcache_range((unsigned long)state->bounce_buffer,
  					(unsigned long)(state->bounce_buffer) +
  						state->len_aligned);
  	}

  	if (state->bounce_buffer == state->user_buffer)

  		return 0;

  	if (state->flags & GEN_BB_WRITE)
  		memcpy(state->user_buffer, state->bounce_buffer, state->len);

  	free(state->bounce_buffer);

  
  	return 0;
  }