path: root/drivers/net/wireless/bcm43xx/bcm43xx_dma.c

/*

  Broadcom BCM43xx wireless driver

  DMA ringbuffer and descriptor allocation/management

  Copyright (c) 2005 Michael Buesch <mbuesch@freenet.de>

  Some code in this file is derived from the b44.c driver
  Copyright (C) 2002 David S. Miller
  Copyright (C) Pekka Pietikainen

  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 2 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; see the file COPYING.  If not, write to
  the Free Software Foundation, Inc., 51 Franklin Steet, Fifth Floor,
  Boston, MA 02110-1301, USA.

*/

#include "bcm43xx.h"
#include "bcm43xx_dma.h"
#include "bcm43xx_main.h"
#include "bcm43xx_debugfs.h"
#include "bcm43xx_power.h"
#include "bcm43xx_xmit.h"

#include <linux/dmapool.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/skbuff.h>
#include <asm/semaphore.h>


static inline int free_slots(struct bcm43xx_dmaring *ring)
{
	return (ring->nr_slots - ring->used_slots);
}

static inline int next_slot(struct bcm43xx_dmaring *ring, int slot)
{
	assert(slot >= -1 && slot <= ring->nr_slots - 1);
	if (slot == ring->nr_slots - 1)
		return 0;
	return slot + 1;
}

static inline int prev_slot(struct bcm43xx_dmaring *ring, int slot)
{
	assert(slot >= 0 && slot <= ring->nr_slots - 1);
	if (slot == 0)
		return ring->nr_slots - 1;
	return slot - 1;
}

/* Request a slot for usage. */
static inline
int request_slot(struct bcm43xx_dmaring *ring)
{
	int slot;

	assert(ring->tx);
	assert(!ring->suspended);
	assert(free_slots(ring) != 0);

	slot = next_slot(ring, ring->current_slot);
	ring->current_slot = slot;
	ring->used_slots++;

	/* Check the number of available slots and suspend TX,
	 * if we are running low on free slots.
	 */
	if (unlikely(free_slots(ring) < ring->suspend_mark)) {
		netif_stop_queue(ring->bcm->net_dev);
		ring->suspended = 1;
	}
#ifdef CONFIG_BCM43XX_DEBUG
	if (ring->used_slots > ring->max_used_slots)
		ring->max_used_slots = ring->used_slots;
#endif /* CONFIG_BCM43XX_DEBUG*/

	return slot;
}

/* Return a slot to the free slots. */
static inline
void return_slot(struct bcm43xx_dmaring *ring, int slot)
{
	assert(ring->tx);

	ring->used_slots--;

	/* Check if TX is suspended and check if we have
	 * enough free slots to resume it again.
	 */
	if (unlikely(ring->suspended)) {
		if (free_slots(ring) >= ring->resume_mark) {
			ring->suspended = 0;
			netif_wake_queue(ring->bcm->net_dev);
		}
	}
}

static inline
dma_addr_t map_descbuffer(struct bcm43xx_dmaring *ring,
			  unsigned char *buf,
			  size_t len,
			  int tx)
{
	dma_addr_t dmaaddr;

	if (tx) {
		dmaaddr = dma_map_single(&ring->bcm->pci_dev->dev,
					 buf, len,
					 DMA_TO_DEVICE);
	} else {
		dmaaddr = dma_map_single(&ring->bcm->pci_dev->dev,
					 buf, len,
					 DMA_FROM_DEVICE);
	}

	return dmaaddr;
}

static inline
void unmap_descbuffer(struct bcm43xx_dmaring *ring,
		      dma_addr_t addr,
		      size_t len,
		      int tx)
{
	if (tx) {
		dma_unmap_single(&ring->bcm->pci_dev->dev,
				 addr, len,
				 DMA_TO_DEVICE);
	} else {
		dma_unmap_single(&ring->bcm->pci_dev->dev,
				 addr, len,
				 DMA_FROM_DEVICE);
	}
}

static inline
void sync_descbuffer_for_cpu(struct bcm43xx_dmaring *ring,
			     dma_addr_t addr,
			     size_t len)
{
	assert(!ring->tx);

	dma_sync_single_for_cpu(&ring->bcm->pci_dev->dev,
				addr, len, DMA_FROM_DEVICE);
}

static inline
void sync_descbuffer_for_device(struct bcm43xx_dmaring *ring,
				dma_addr_t addr,
				size_t len)
{
	assert(!ring->tx);

	dma_sync_single_for_device(&ring->bcm->pci_dev->dev,
				   addr, len, DMA_FROM_DEVICE);
}

/* Unmap and free a descriptor buffer. */
static inline
void free_descriptor_buffer(struct bcm43xx_dmaring *ring,
			    struct bcm43xx_dmadesc *desc,
			    struct bcm43xx_dmadesc_meta *meta,
			    int irq_context)
{
	assert(meta->skb);
	if (