pio.c

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/*

  Broadcom B43legacy wireless driver

  PIO Transmission

  Copyright (c) 2005 Michael Buesch <[email protected]>

  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>
#include <linux/slab.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,
                 IEEE80211_SKB_CB(skb),
                 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);

    INIT_LIST_HEAD(&queue->txfree);
    INIT_LIST_HEAD(&queue->txqueue);
    INIT_LIST_HEAD(&queue->txrunning);
    tasklet_init(&queue->txtask, tx_tasklet,
             (unsigned long)queue);

    value = b43legacy_read32(dev, B43legacy_MMIO_MACCTL);
    value &= ~B43legacy_MACCTL_BE;
    b43legacy_write32(dev, B43legacy_MMIO_MACCTL, value);

    qsize = b43legacy_read16(dev, queue->mmio_base
                 + B43legacy_PIO_TXQBUFSIZE);
    if (qsize == 0) {
        b43legacyerr(dev->wl, "This card does not support PIO "
               "operation mode. Please use DMA mode "
               "(module parameter pio=0).\n");
        goto err_freequeue;
    }
    if (qsize <= B43legacy_PIO_TXQADJUST) {
        b43legacyerr(dev->wl, "PIO tx device-queue too small (%u)\n",
               qsize);
        goto err_freequeue;
    }
    qsize -= B43legacy_PIO_TXQADJUST;
    queue->tx_devq_size = qsize;

    setup_txqueues(queue);

out:
    return queue;

err_freequeue:
    kfree(queue);
    queue = NULL;
    goto out;
}

static void cancel_transfers(struct b43legacy_pioqueue *queue)
{
    struct b43legacy_pio_txpacket *packet, *tmp_packet;

    tasklet_kill(&queue->txtask);

    list_for_each_entry_safe(packet, tmp_packet, &queue->txrunning, list)
        free_txpacket(packet, 0);
    list_for_each_entry_safe(packet, tmp_packet, &queue->txqueue, list)
        free_txpacket(packet, 0);
}

static void b43legacy_destroy_pioqueue(struct b43legacy_pioqueue *queue)
{
    if (!queue)
        return;

    cancel_transfers(queue);
    kfree(queue);
}

void b43legacy_pio_free(struct b43legacy_wldev *dev)
{
    struct b43legacy_pio *pio;

    if (!b43legacy_using_pio(dev))
        return;
    pio = &dev->pio;

    b43legacy_destroy_pioqueue(pio->queue3);
    pio->queue3 = NULL;
    b43legacy_destroy_pioqueue(pio->queue2);
    pio->queue2 = NULL;
    b43legacy_destroy_pioqueue(pio->queue1);
    pio->queue1 = NULL;
    b43legacy_destroy_pioqueue(pio->queue0);
    pio->queue0 = NULL;
}

int b43legacy_pio_init(struct b43legacy_wldev *dev)
{
    struct b43legacy_pio *pio = &dev->pio;
    struct b43legacy_pioqueue *queue;
    int err = -ENOMEM;

    queue = b43legacy_setup_pioqueue(dev, B43legacy_MMIO_PIO1_BASE);
    if (!queue)
        goto out;
    pio->queue0 = queue;

    queue = b43legacy_setup_pioqueue(dev, B43legacy_MMIO_PIO2_BASE);
    if (!queue)
        goto err_destroy0;
    pio->queue1 = queue;

    queue = b43legacy_setup_pioqueue(dev, B43legacy_MMIO_PIO3_BASE);
    if (!queue)
        goto err_destroy1;
    pio->queue2 = queue;

    queue = b43legacy_setup_pioqueue(dev, B43legacy_MMIO_PIO4_BASE);
    if (!queue)
        goto err_destroy2;
    pio->queue3 = queue;

    if (dev->dev->id.revision < 3)
        dev->irq_mask |= B43legacy_IRQ_PIO_WORKAROUND;

    b43legacydbg(dev->wl, "PIO initialized\n");
    err = 0;
out:
    return err;

err_destroy2:
    b43legacy_destroy_pioqueue(pio->queue2);
    pio->queue2 = NULL;
err_destroy1:
    b43legacy_destroy_pioqueue(pio->queue1);
    pio->queue1 = NULL;
err_destroy0:
    b43legacy_destroy_pioqueue(pio->queue0);
    pio->queue0 = NULL;
    goto out;
}

int b43legacy_pio_tx(struct b43legacy_wldev *dev,
             struct sk_buff *skb)
{
    struct b43legacy_pioqueue *queue = dev->pio.queue1;
    struct b43legacy_pio_txpacket *packet;

    B43legacy_WARN_ON(queue->tx_suspended);
    B43legacy_WARN_ON(list_empty(&queue->txfree));

    packet = list_entry(queue->txfree.next, struct b43legacy_pio_txpacket,
                list);
    packet->skb = skb;

    list_move_tail(&packet->list, &queue->txqueue);
    queue->nr_txfree--;
    B43legacy_WARN_ON(queue->nr_txfree >= B43legacy_PIO_MAXTXPACKETS);

    tasklet_schedule(&queue->txtask);

    return 0;
}

void b43legacy_pio_handle_txstatus(struct b43legacy_wldev *dev,
                   const struct b43legacy_txstatus *status)
{
    struct b43legacy_pioqueue *queue;
    struct b43legacy_pio_txpacket *packet;
    struct ieee80211_tx_info *info;
    int retry_limit;

    queue = parse_cookie(dev, status->cookie, &packet);
    B43legacy_WARN_ON(!queue);

    if (!packet->skb)
        return;

    queue->tx_devq_packets--;
    queue->tx_devq_used -= (packet->skb->len +
                sizeof(struct b43legacy_txhdr_fw3));

    info = IEEE80211_SKB_CB(packet->skb);

    /* preserve the confiured retry limit before clearing the status
     * The xmit function has overwritten the rc's value with the actual
     * retry limit done by the hardware */
    retry_limit = info->status.rates[0].count;
    ieee80211_tx_info_clear_status(info);

    if (status->acked)
        info->flags |= IEEE80211_TX_STAT_ACK;

    if (status->rts_count > dev->wl->hw->conf.short_frame_max_tx_count) {
        /*
         * If the short retries (RTS, not data frame) have exceeded
         * the limit, the hw will not have tried the selected rate,
         * but will have used the fallback rate instead.
         * Don't let the rate control count attempts for the selected
         * rate in this case, otherwise the statistics will be off.
         */
        info->status.rates[0].count = 0;
        info->status.rates[1].count = status->frame_count;
    } else {
        if (status->frame_count > retry_limit) {
            info->status.rates[0].count = retry_limit;
            info->status.rates[1].count = status->frame_count -
                    retry_limit;

        } else {
            info->status.rates[0].count = status->frame_count;
            info->status.rates[1].idx = -1;
        }
    }
    ieee80211_tx_status_irqsafe(dev->wl->hw, packet->skb);
    packet->skb = NULL;

    free_txpacket(packet, 1);
    /* If there are packets on the txqueue, poke the tasklet
     * to transmit them.
     */
    if (!list_empty(&queue->txqueue))
        tasklet_schedule(&queue->txtask);
}

static void pio_rx_error(struct b43legacy_pioqueue *queue,
             int clear_buffers,
             const char *error)
{
    int i;

    b43legacyerr(queue->dev->wl, "PIO RX error: %s\n", error);
    b43legacy_pio_write(queue, B43legacy_PIO_RXCTL,
                B43legacy_PIO_RXCTL_READY);
    if (clear_buffers) {
        B43legacy_WARN_ON(queue->mmio_base != B43legacy_MMIO_PIO1_BASE);
        for (i = 0; i < 15; i++) {
            /* Dummy read. */
            b43legacy_pio_read(queue, B43legacy_PIO_RXDATA);
        }
    }
}

void b43legacy_pio_rx(struct b43legacy_pioqueue *queue)
{
    __le16 preamble[21] = { 0 };
    struct b43legacy_rxhdr_fw3 *rxhdr;
    u16 tmp;
    u16 len;
    u16 macstat;
    int i;
    int preamble_readwords;
    struct sk_buff *skb;

    tmp = b43legacy_pio_read(queue, B43legacy_PIO_RXCTL);
    if (!(tmp & B43legacy_PIO_RXCTL_DATAAVAILABLE))
        return;
    b43legacy_pio_write(queue, B43legacy_PIO_RXCTL,
                B43legacy_PIO_RXCTL_DATAAVAILABLE);

    for (i = 0; i < 10; i++) {
        tmp = b43legacy_pio_read(queue, B43legacy_PIO_RXCTL);
        if (tmp & B43legacy_PIO_RXCTL_READY)
            goto data_ready;
        udelay(10);
    }
    b43legacydbg(queue->dev->wl, "PIO RX timed out\n");
    return;
data_ready:

    len = b43legacy_pio_read(queue, B43legacy_PIO_RXDATA);
    if (unlikely(len > 0x700)) {
        pio_rx_error(queue, 0, "len > 0x700");
        return;
    }
    if (unlikely(len == 0 && queue->mmio_base !=
             B43legacy_MMIO_PIO4_BASE)) {
        pio_rx_error(queue, 0, "len == 0");
        return;
    }
    preamble[0] = cpu_to_le16(len);
    if (queue->mmio_base == B43legacy_MMIO_PIO4_BASE)
        preamble_readwords = 14 / sizeof(u16);
    else
        preamble_readwords = 18 / sizeof(u16);
    for (i = 0; i < preamble_readwords; i++) {
        tmp = b43legacy_pio_read(queue, B43legacy_PIO_RXDATA);
        preamble[i + 1] = cpu_to_le16(tmp);
    }
    rxhdr = (struct b43legacy_rxhdr_fw3 *)preamble;
    macstat = le16_to_cpu(rxhdr->mac_status);
    if (macstat & B43legacy_RX_MAC_FCSERR) {
        pio_rx_error(queue,
                 (queue->mmio_base == B43legacy_MMIO_PIO1_BASE),
                 "Frame FCS error");
        return;
    }
    if (queue->mmio_base == B43legacy_MMIO_PIO4_BASE) {
        /* We received an xmit status. */
        struct b43legacy_hwtxstatus *hw;

        hw = (struct b43legacy_hwtxstatus *)(preamble + 1);
        b43legacy_handle_hwtxstatus(queue->dev, hw);

        return;
    }

    skb = dev_alloc_skb(len);
    if (unlikely(!skb)) {
        pio_rx_error(queue, 1, "OOM");
        return;
    }
    skb_put(skb, len);
    for (i = 0; i < len - 1; i += 2) {
        tmp = b43legacy_pio_read(queue, B43legacy_PIO_RXDATA);
        *((__le16 *)(skb->data + i)) = cpu_to_le16(tmp);
    }
    if (len % 2) {
        tmp = b43legacy_pio_read(queue, B43legacy_PIO_RXDATA);
        skb->data[len - 1] = (tmp & 0x00FF);
    }
    b43legacy_rx(queue->dev, skb, rxhdr);
}

void b43legacy_pio_tx_suspend(struct b43legacy_pioqueue *queue)
{
    b43legacy_power_saving_ctl_bits(queue->dev, -1, 1);
    b43legacy_pio_write(queue, B43legacy_PIO_TXCTL,
                b43legacy_pio_read(queue, B43legacy_PIO_TXCTL)
                | B43legacy_PIO_TXCTL_SUSPEND);
}

void b43legacy_pio_tx_resume(struct b43legacy_pioqueue *queue)
{
    b43legacy_pio_write(queue, B43legacy_PIO_TXCTL,
                b43legacy_pio_read(queue, B43legacy_PIO_TXCTL)
                & ~B43legacy_PIO_TXCTL_SUSPEND);
    b43legacy_power_saving_ctl_bits(queue->dev, -1, -1);
    tasklet_schedule(&queue->txtask);
}

void b43legacy_pio_freeze_txqueues(struct b43legacy_wldev *dev)
{
    struct b43legacy_pio *pio;

    B43legacy_WARN_ON(!b43legacy_using_pio(dev));
    pio = &dev->pio;
    pio->queue0->tx_frozen = 1;
    pio->queue1->tx_frozen = 1;
    pio->queue2->tx_frozen = 1;
    pio->queue3->tx_frozen = 1;
}

void b43legacy_pio_thaw_txqueues(struct b43legacy_wldev *dev)
{
    struct b43legacy_pio *pio;

    B43legacy_WARN_ON(!b43legacy_using_pio(dev));
    pio = &dev->pio;
    pio->queue0->tx_frozen = 0;
    pio->queue1->tx_frozen = 0;
    pio->queue2->tx_frozen = 0;
    pio->queue3->tx_frozen = 0;
    if (!list_empty(&pio->queue0->txqueue))
        tasklet_schedule(&pio->queue0->txtask);
    if (!list_empty(&pio->queue1->txqueue))
        tasklet_schedule(&pio->queue1->txtask);
    if (!list_empty(&pio->queue2->txqueue))
        tasklet_schedule(&pio->queue2->txtask);
    if (!list_empty(&pio->queue3->txqueue))
        tasklet_schedule(&pio->queue3->txtask);
}