pio.c

linux 内核源代码

/*

  Broadcom B43legacy wireless driver

  PIO Transmission

  Copyright (c) 2005 Michael Buesch <[e-mail]>

  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 "b43legacy.h"
#include "pio.h"
#include "main.h"
#include "xmit.h"

#include <linux/delay.h>


static void tx_start(struct b43legacy_pioqueue *queue)
{
	b43legacy_pio_write(queue, B43legacy_PIO_TXCTL,
			    B43legacy_PIO_TXCTL_INIT);
}

static void tx_octet(struct b43legacy_pioqueue *queue,
		     u8 octet)
{
	if (queue->need_workarounds) {
		b43legacy_pio_write(queue, B43legacy_PIO_TXDATA, octet);
		b43legacy_pio_write(queue, B43legacy_PIO_TXCTL,
				    B43legacy_PIO_TXCTL_WRITELO);
	} else {
		b43legacy_pio_write(queue, B43legacy_PIO_TXCTL,
				    B43legacy_PIO_TXCTL_WRITELO);
		b43legacy_pio_write(queue, B43legacy_PIO_TXDATA, octet);
	}
}

static u16 tx_get_next_word(const u8 *txhdr,
			    const u8 *packet,
			    size_t txhdr_size,
			    unsigned int *pos)
{
	const u8 *source;
	unsigned int i = *pos;
	u16 ret;

	if (i < txhdr_size)
		source = txhdr;
	else {
		source = packet;
		i -= txhdr_size;
	}
	ret = le16_to_cpu(*((__le16 *)(source + i)));
	*pos += 2;

	return ret;
}

static void tx_data(struct b43legacy_pioqueue *queue,
		    u8 *txhdr,
		    const u8 *packet,
		    unsigned int octets)
{
	u16 data;
	unsigned int i = 0;

	if (queue->need_workarounds) {
		data = tx_get_next_word(txhdr, packet,
					sizeof(struct b43legacy_txhdr_fw3), &i);
		b43legacy_pio_write(queue, B43legacy_PIO_TXDATA, data);
	}
	b43legacy_pio_write(queue, B43legacy_PIO_TXCTL,
			    B43legacy_PIO_TXCTL_WRITELO |
			    B43legacy_PIO_TXCTL_WRITEHI);
	while (i < octets - 1) {
		data = tx_get_next_word(txhdr, packet,
					sizeof(struct b43legacy_txhdr_fw3), &i);
		b43legacy_pio_write(queue, B43legacy_PIO_TXDATA, data);
	}
	if (octets % 2)
		tx_octet(queue, packet[octets -
			 sizeof(struct b43legacy_txhdr_fw3) - 1]);
}

static void tx_complete(struct b43legacy_pioqueue *queue,
			struct sk_buff *skb)
{
	if (queue->need_workarounds) {
		b43legacy_pio_write(queue, B43legacy_PIO_TXDATA,
				    skb->data[skb->len - 1]);
		b43legacy_pio_write(queue, B43legacy_PIO_TXCTL,
				    B43legacy_PIO_TXCTL_WRITELO |
				    B43legacy_PIO_TXCTL_COMPLETE);
	} else
		b43legacy_pio_write(queue, B43legacy_PIO_TXCTL,
				    B43legacy_PIO_TXCTL_COMPLETE);
}

static u16 generate_cookie(struct b43legacy_pioqueue *queue,
			   struct b43legacy_pio_txpacket *packet)
{
	u16 cookie = 0x0000;
	int packetindex;

	/* We use the upper 4 bits for the PIO
	 * controller ID and the lower 12 bits
	 * for the packet index (in the cache).
	 */
	switch (queue->mmio_base) {
	case B43legacy_MMIO_PIO1_BASE:
		break;
	case B43legacy_MMIO_PIO2_BASE:
		cookie = 0x1000;
		break;
	case B43legacy_MMIO_PIO3_BASE:
		cookie = 0x2000;
		break;
	case B43legacy_MMIO_PIO4_BASE:
		cookie = 0x3000;
		break;
	default:
		B43legacy_WARN_ON(1);
	}
	packetindex = pio_txpacket_getindex(packet);
	B43legacy_WARN_ON(!(((u16)packetindex & 0xF000) == 0x0000));
	cookie |= (u16)packetindex;

	return cookie;
}

static
struct b43legacy_pioqueue *parse_cookie(struct b43legacy_wldev *dev,
					u16 cookie,
					struct b43legacy_pio_txpacket **packet)
{
	struct b43legacy_pio *pio = &dev->pio;
	struct b43legacy_pioqueue *queue = NULL;
	int packetindex;

	switch (cookie & 0xF000) {
	case 0x0000:
		queue = pio->queue0;
		break;
	case 0x1000:
		queue = pio->queue1;
		break;
	case 0x2000:
		queue = pio->queue2;
		break;
	case 0x3000:
		queue = pio->queue3;
		break;
	default:
		B43legacy_WARN_ON(1);
	}
	packetindex = (cookie & 0x0FFF);
	B43legacy_WARN_ON(!(packetindex >= 0 && packetindex
			  < B43legacy_PIO_MAXTXPACKETS));
	*packet = &(queue->tx_packets_cache[packetindex]);

	return queue;
}

union txhdr_union {
	struct b43legacy_txhdr_fw3 txhdr_fw3;
};

static int pio_tx_write_fragment(struct b43legacy_pioqueue *queue,
				  struct sk_buff *skb,
				  struct b43legacy_pio_txpacket *packet,
				  size_t txhdr_size)
{
	union txhdr_union txhdr_data;
	u8 *txhdr = NULL;
	unsigned int octets;
	int err;

	txhdr = (u8 *)(&txhdr_data.txhdr_fw3);

	B43legacy_WARN_ON(skb_shinfo(skb)->nr_frags != 0);
	err = b43legacy_generate_txhdr(queue->dev,
				 txhdr, skb->data, skb->len,
				 &packet->txstat.control,
				 generate_cookie(queue, packet));
	if (err)
		return err;

	tx_start(queue);
	octets = skb->len + txhdr_size;
	if (queue->need_workarounds)
		octets--;
	tx_data(queue, txhdr, (u8 *)skb->data, octets);
	tx_complete(queue, skb);

	return 0;
}

static void free_txpacket(struct b43legacy_pio_txpacket *packet,
			  int irq_context)
{
	struct b43legacy_pioqueue *queue = packet->queue;

	if (packet->skb) {
		if (irq_context)
			dev_kfree_skb_irq(packet->skb);
		else
			dev_kfree_skb(packet->skb);
	}
	list_move(&packet->list, &queue->txfree);
	queue->nr_txfree++;
}

static int pio_tx_packet(struct b43legacy_pio_txpacket *packet)
{
	struct b43legacy_pioqueue *queue = packet->queue;
	struct sk_buff *skb = packet->skb;
	u16 octets;
	int err;

	octets = (u16)skb->len + sizeof(struct b43legacy_txhdr_fw3);
	if (queue->tx_devq_size < octets) {
		b43legacywarn(queue->dev->wl, "PIO queue too small. "
			"Dropping packet.\n");
		/* Drop it silently (return success) */
		free_txpacket(packet, 1);
		return 0;
	}
	B43legacy_WARN_ON(queue->tx_devq_packets >
			  B43legacy_PIO_MAXTXDEVQPACKETS);
	B43legacy_WARN_ON(queue->tx_devq_used > queue->tx_devq_size);
	/* Check if there is sufficient free space on the device
	 * TX queue. If not, return and let the TX tasklet
	 * retry later.
	 */
	if (queue->tx_devq_packets == B43legacy_PIO_MAXTXDEVQPACKETS)
		return -EBUSY;
	if (queue->tx_devq_used + octets > queue->tx_devq_size)
		return -EBUSY;
	/* Now poke the device. */
	err = pio_tx_write_fragment(queue, skb, packet,
			      sizeof(struct b43legacy_txhdr_fw3));
	if (unlikely(err == -ENOKEY)) {
		/* Drop this packet, as we don't have the encryption key
		 * anymore and must not transmit it unencrypted. */
		free_txpacket(packet, 1);
		return 0;
	}

	/* Account for the packet size.
	 * (We must not overflow the device TX queue)
	 */
	queue->tx_devq_packets++;
	queue->tx_devq_used += octets;

	/* Transmission started, everything ok, move the
	 * packet to the txrunning list.
	 */
	list_move_tail(&packet->list, &queue->txrunning);

	return 0;
}

static void tx_tasklet(unsigned long d)
{
	struct b43legacy_pioqueue *queue = (struct b43legacy_pioqueue *)d;
	struct b43legacy_wldev *dev = queue->dev;
	unsigned long flags;
	struct b43legacy_pio_txpacket *packet, *tmp_packet;
	int err;
	u16 txctl;

	spin_lock_irqsave(&dev->wl->irq_lock, flags);
	if (queue->tx_frozen)
		goto out_unlock;
	txctl = b43legacy_pio_read(queue, B43legacy_PIO_TXCTL);
	if (txctl & B43legacy_PIO_TXCTL_SUSPEND)
		goto out_unlock;

	list_for_each_entry_safe(packet, tmp_packet, &queue->txqueue, list) {
		/* Try to transmit the packet. This can fail, if
		 * the device queue is full. In case of failure, the
		 * packet is left in the txqueue.
		 * If transmission succeed, the packet is moved to txrunning.
		 * If it is impossible to transmit the packet, it
		 * is dropped.
		 */
		err = pio_tx_packet(packet);
		if (err)
			break;
	}
out_unlock:
	spin_unlock_irqrestore(&dev->wl->irq_lock, flags);
}

static void setup_txqueues(struct b43legacy_pioqueue *queue)
{
	struct b43legacy_pio_txpacket *packet;
	int i;

	queue->nr_txfree = B43legacy_PIO_MAXTXPACKETS;
	for (i = 0; i < B43legacy_PIO_MAXTXPACKETS; i++) {
		packet = &(queue->tx_packets_cache[i]);

		packet->queue = queue;
		INIT_LIST_HEAD(&packet->list);

		list_add(&packet->list, &queue->txfree);
	}
}

static
struct b43legacy_pioqueue *b43legacy_setup_pioqueue(struct b43legacy_wldev *dev,
						    u16 pio_mmio_base)
{
	struct b43legacy_pioqueue *queue;
	u32 value;
	u16 qsize;

	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
	if (!queue)
		goto out;

	queue->dev = dev;
	queue->mmio_base = pio_mmio_base;
	queue->need_workarounds = (dev->dev->id.revision < 3);