sa1100_ir.c

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/*
 *  linux/drivers/net/irda/sa1100_ir.c
 *
 *  Copyright (C) 2000-2001 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  Infra-red driver for the StrongARM SA1100 embedded microprocessor
 *
 *  Note that we don't have to worry about the SA1111's DMA bugs in here,
 *  so we use the straight forward dma_map_* functions with a null pointer.
 *
 *  This driver takes one kernel command line parameter, sa1100ir=, with
 *  the following options:
 *  max_rate:baudrate   - set the maximum baud rate
 *  power_level:level   - set the transmitter power level
 *  tx_lpm:0|1      - set transmit low power mode
 */
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/slab.h>
#include <linux/rtnetlink.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/sa11x0-dma.h>

#include <net/irda/irda.h>
#include <net/irda/wrapper.h>
#include <net/irda/irda_device.h>

#include <mach/hardware.h>
#include <asm/mach/irda.h>

static int power_level = 3;
static int tx_lpm;
static int max_rate = 4000000;

struct sa1100_buf {
    struct device       *dev;
    struct sk_buff      *skb;
    struct scatterlist  sg;
    struct dma_chan     *chan;
    dma_cookie_t        cookie;
};

struct sa1100_irda {
    unsigned char       utcr4;
    unsigned char       power;
    unsigned char       open;

    int         speed;
    int         newspeed;

    struct sa1100_buf   dma_rx;
    struct sa1100_buf   dma_tx;

    struct device       *dev;
    struct irda_platform_data *pdata;
    struct irlap_cb     *irlap;
    struct qos_info     qos;

    iobuff_t        tx_buff;
    iobuff_t        rx_buff;

    int (*tx_start)(struct sk_buff *, struct net_device *, struct sa1100_irda *);
    irqreturn_t (*irq)(struct net_device *, struct sa1100_irda *);
};

static int sa1100_irda_set_speed(struct sa1100_irda *, int);

#define IS_FIR(si)      ((si)->speed >= 4000000)

#define HPSIR_MAX_RXLEN     2047

static struct dma_slave_config sa1100_irda_sir_tx = {
    .direction  = DMA_TO_DEVICE,
    .dst_addr   = __PREG(Ser2UTDR),
    .dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
    .dst_maxburst   = 4,
};

static struct dma_slave_config sa1100_irda_fir_rx = {
    .direction  = DMA_FROM_DEVICE,
    .src_addr   = __PREG(Ser2HSDR),
    .src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
    .src_maxburst   = 8,
};

static struct dma_slave_config sa1100_irda_fir_tx = {
    .direction  = DMA_TO_DEVICE,
    .dst_addr   = __PREG(Ser2HSDR),
    .dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
    .dst_maxburst   = 8,
};

static unsigned sa1100_irda_dma_xferred(struct sa1100_buf *buf)
{
    struct dma_chan *chan = buf->chan;
    struct dma_tx_state state;
    enum dma_status status;

    status = chan->device->device_tx_status(chan, buf->cookie, &state);
    if (status != DMA_PAUSED)
        return 0;

    return sg_dma_len(&buf->sg) - state.residue;
}

static int sa1100_irda_dma_request(struct device *dev, struct sa1100_buf *buf,
    const char *name, struct dma_slave_config *cfg)
{
    dma_cap_mask_t m;
    int ret;

    dma_cap_zero(m);
    dma_cap_set(DMA_SLAVE, m);

    buf->chan = dma_request_channel(m, sa11x0_dma_filter_fn, (void *)name);
    if (!buf->chan) {
        dev_err(dev, "unable to request DMA channel for %s\n",
            name);
        return -ENOENT;
    }

    ret = dmaengine_slave_config(buf->chan, cfg);
    if (ret)
        dev_warn(dev, "DMA slave_config for %s returned %d\n",
            name, ret);

    buf->dev = buf->chan->device->dev;

    return 0;
}

static void sa1100_irda_dma_start(struct sa1100_buf *buf,
    enum dma_transfer_direction dir, dma_async_tx_callback cb, void *cb_p)
{
    struct dma_async_tx_descriptor *desc;
    struct dma_chan *chan = buf->chan;

    desc = dmaengine_prep_slave_sg(chan, &buf->sg, 1, dir,
            DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
    if (desc) {
        desc->callback = cb;
        desc->callback_param = cb_p;
        buf->cookie = dmaengine_submit(desc);
        dma_async_issue_pending(chan);
    }
}

/*
 * Allocate and map the receive buffer, unless it is already allocated.
 */
static int sa1100_irda_rx_alloc(struct sa1100_irda *si)
{
    if (si->dma_rx.skb)
        return 0;

    si->dma_rx.skb = alloc_skb(HPSIR_MAX_RXLEN + 1, GFP_ATOMIC);
    if (!si->dma_rx.skb) {
        printk(KERN_ERR "sa1100_ir: out of memory for RX SKB\n");
        return -ENOMEM;
    }

    /*
     * Align any IP headers that may be contained
     * within the frame.
     */
    skb_reserve(si->dma_rx.skb, 1);

    sg_set_buf(&si->dma_rx.sg, si->dma_rx.skb->data, HPSIR_MAX_RXLEN);
    if (dma_map_sg(si->dma_rx.dev, &si->dma_rx.sg, 1, DMA_FROM_DEVICE) == 0) {
        dev_kfree_skb_any(si->dma_rx.skb);
        return -ENOMEM;
    }

    return 0;
}

/*
 * We want to get here as soon as possible, and get the receiver setup.
 * We use the existing buffer.
 */
static void sa1100_irda_rx_dma_start(struct sa1100_irda *si)
{
    if (!si->dma_rx.skb) {
        printk(KERN_ERR "sa1100_ir: rx buffer went missing\n");
        return;
    }

    /*
     * First empty receive FIFO
     */
    Ser2HSCR0 = HSCR0_HSSP;

    /*
     * Enable the DMA, receiver and receive interrupt.
     */
    dmaengine_terminate_all(si->dma_rx.chan);
    sa1100_irda_dma_start(&si->dma_rx, DMA_DEV_TO_MEM, NULL, NULL);

    Ser2HSCR0 = HSCR0_HSSP | HSCR0_RXE;
}

static void sa1100_irda_check_speed(struct sa1100_irda *si)
{
    if (si->newspeed) {
        sa1100_irda_set_speed(si, si->newspeed);
        si->newspeed = 0;
    }
}

/*
 * HP-SIR format support.
 */
static void sa1100_irda_sirtxdma_irq(void *id)
{
    struct net_device *dev = id;
    struct sa1100_irda *si = netdev_priv(dev);

    dma_unmap_sg(si->dma_tx.dev, &si->dma_tx.sg, 1, DMA_TO_DEVICE);
    dev_kfree_skb(si->dma_tx.skb);
    si->dma_tx.skb = NULL;

    dev->stats.tx_packets++;
    dev->stats.tx_bytes += sg_dma_len(&si->dma_tx.sg);

    /* We need to ensure that the transmitter has finished. */
    do
        rmb();
    while (Ser2UTSR1 & UTSR1_TBY);

    /*
     * Ok, we've finished transmitting.  Now enable the receiver.
     * Sometimes we get a receive IRQ immediately after a transmit...
     */
    Ser2UTSR0 = UTSR0_REB | UTSR0_RBB | UTSR0_RID;
    Ser2UTCR3 = UTCR3_RIE | UTCR3_RXE | UTCR3_TXE;

    sa1100_irda_check_speed(si);

    /* I'm hungry! */
    netif_wake_queue(dev);
}

static int sa1100_irda_sir_tx_start(struct sk_buff *skb, struct net_device *dev,
    struct sa1100_irda *si)
{
    si->tx_buff.data = si->tx_buff.head;
    si->tx_buff.len  = async_wrap_skb(skb, si->tx_buff.data,
                      si->tx_buff.truesize);

    si->dma_tx.skb = skb;
    sg_set_buf(&si->dma_tx.sg, si->tx_buff.data, si->tx_buff.len);
    if (dma_map_sg(si->dma_tx.dev, &si->dma_tx.sg, 1, DMA_TO_DEVICE) == 0) {
        si->dma_tx.skb = NULL;
        netif_wake_queue(dev);
        dev->stats.tx_dropped++;
        return NETDEV_TX_OK;
    }

    sa1100_irda_dma_start(&si->dma_tx, DMA_MEM_TO_DEV, sa1100_irda_sirtxdma_irq, dev);

    /*
     * The mean turn-around time is enforced by XBOF padding,
     * so we don't have to do anything special here.
     */
    Ser2UTCR3 = UTCR3_TXE;

    return NETDEV_TX_OK;
}

static irqreturn_t sa1100_irda_sir_irq(struct net_device *dev, struct sa1100_irda *si)
{
    int status;

    status = Ser2UTSR0;

    /*
     * Deal with any receive errors first.  The bytes in error may be
     * the only bytes in the receive FIFO, so we do this first.
     */
    while (status & UTSR0_EIF) {
        int stat, data;

        stat = Ser2UTSR1;
        data = Ser2UTDR;

        if (stat & (UTSR1_FRE | UTSR1_ROR)) {
            dev->stats.rx_errors++;
            if (stat & UTSR1_FRE)
                dev->stats.rx_frame_errors++;
            if (stat & UTSR1_ROR)
                dev->stats.rx_fifo_errors++;
        } else
            async_unwrap_char(dev, &dev->stats, &si->rx_buff, data);

        status = Ser2UTSR0;
    }

    /*
     * We must clear certain bits.
     */
    Ser2UTSR0 = status & (UTSR0_RID | UTSR0_RBB | UTSR0_REB);

    if (status & UTSR0_RFS) {
        /*
         * There are at least 4 bytes in the FIFO.  Read 3 bytes
         * and leave the rest to the block below.
         */
        async_unwrap_char(dev, &dev->stats, &si->rx_buff, Ser2UTDR);
        async_unwrap_char(dev, &dev->stats, &si->rx_buff, Ser2UTDR);
        async_unwrap_char(dev, &dev->stats, &si->rx_buff, Ser2UTDR);
    }

    if (status & (UTSR0_RFS | UTSR0_RID)) {
        /*
         * Fifo contains more than 1 character.
         */
        do {
            async_unwrap_char(dev, &dev->stats, &si->rx_buff,
                      Ser2UTDR);
        } while (Ser2UTSR1 & UTSR1_RNE);

    }

    return IRQ_HANDLED;
}

/*
 * FIR format support.
 */
static void sa1100_irda_firtxdma_irq(void *id)
{
    struct net_device *dev = id;
    struct sa1100_irda *si = netdev_priv(dev);
    struct sk_buff *skb;

    /*
     * Wait for the transmission to complete.  Unfortunately,
     * the hardware doesn't give us an interrupt to indicate
     * "end of frame".
     */
    do
        rmb();
    while (!(Ser2HSSR0 & HSSR0_TUR) || Ser2HSSR1 & HSSR1_TBY);

    /*
     * Clear the transmit underrun bit.
     */
    Ser2HSSR0 = HSSR0_TUR;

    /*
     * Do we need to change speed?  Note that we're lazy
     * here - we don't free the old dma_rx.skb.  We don't need
     * to allocate a buffer either.
     */
    sa1100_irda_check_speed(si);

    /*
     * Start reception.  This disables the transmitter for
     * us.  This will be using the existing RX buffer.
     */
    sa1100_irda_rx_dma_start(si);

    /* Account and free the packet. */
    skb = si->dma_tx.skb;
    if (skb) {
        dma_unmap_sg(si->dma_tx.dev, &si->dma_tx.sg, 1,
                 DMA_TO_DEVICE);
        dev->stats.tx_packets ++;
        dev->stats.tx_bytes += skb->len;
        dev_kfree_skb_irq(skb);
        si->dma_tx.skb = NULL;
    }

    /*
     * Make sure that the TX queue is available for sending
     * (for retries).  TX has priority over RX at all times.
     */
    netif_wake_queue(dev);
}

static int sa1100_irda_fir_tx_start(struct sk_buff *skb, struct net_device *dev,
    struct sa1100_irda *si)
{
    int mtt = irda_get_mtt(skb);

    si->dma_tx.skb = skb;
    sg_set_buf(&si->dma_tx.sg, skb->data, skb->len);
    if (dma_map_sg(si->dma_tx.dev, &si->dma_tx.sg, 1, DMA_TO_DEVICE) == 0) {
        si->dma_tx.skb = NULL;
        netif_wake_queue(dev);
        dev->stats.tx_dropped++;
        dev_kfree_skb(skb);
        return NETDEV_TX_OK;
    }

    sa1100_irda_dma_start(&si->dma_tx, DMA_MEM_TO_DEV, sa1100_irda_firtxdma_irq, dev);

    /*
     * If we have a mean turn-around time, impose the specified
     * specified delay.  We could shorten this by timing from
     * the point we received the packet.
     */
    if (mtt)
        udelay(mtt);

    Ser2HSCR0 = HSCR0_HSSP | HSCR0_TXE;

    return NETDEV_TX_OK;
}

static void sa1100_irda_fir_error(struct sa1100_irda *si, struct net_device *dev)
{
    struct sk_buff *skb = si->dma_rx.skb;
    unsigned int len, stat, data;

    if (!skb) {
        printk(KERN_ERR "sa1100_ir: SKB is NULL!\n");
        return;
    }

    /*
     * Get the current data position.
     */
    len = sa1100_irda_dma_xferred(&si->dma_rx);
    if (len > HPSIR_MAX_RXLEN)
        len = HPSIR_MAX_RXLEN;
    dma_unmap_sg(si->dma_rx.dev, &si->dma_rx.sg, 1, DMA_FROM_DEVICE);

    do {
        /*
         * Read Status, and then Data.
         */
        stat = Ser2HSSR1;
        rmb();
        data = Ser2HSDR;

        if (stat & (HSSR1_CRE | HSSR1_ROR)) {
            dev->stats.rx_errors++;
            if (stat & HSSR1_CRE)
                dev->stats.rx_crc_errors++;
            if (stat & HSSR1_ROR)
                dev->stats.rx_frame_errors++;
        } else
            skb->data[len++] = data;

        /*
         * If we hit the end of frame, there's
         * no point in continuing.
         */
        if (stat & HSSR1_EOF)
            break;
    } while (Ser2HSSR0 & HSSR0_EIF);

    if (stat & HSSR1_EOF) {
        si->dma_rx.skb = NULL;

        skb_put(skb, len);
        skb->dev = dev;
        skb_reset_mac_header(skb);
        skb->protocol = htons(ETH_P_IRDA);
        dev->stats.rx_packets++;
        dev->stats.rx_bytes += len;

        /*
         * Before we pass the buffer up, allocate a new one.
         */
        sa1100_irda_rx_alloc(si);

        netif_rx(skb);
    } else {
        /*
         * Remap the buffer - it was previously mapped, and we
         * hope that this succeeds.
         */
        dma_map_sg(si->dma_rx.dev, &si->dma_rx.sg, 1, DMA_FROM_DEVICE);
    }
}

/*
 * We only have to handle RX events here; transmit events go via the TX
 * DMA handler. We disable RX, process, and the restart RX.
 */
static irqreturn_t sa1100_irda_fir_irq(struct net_device *dev, struct sa1100_irda *si)
{
    /*
     * Stop RX DMA
     */
    dmaengine_pause(si->dma_rx.chan);

    /*
     * Framing error - we throw away the packet completely.
     * Clearing RXE flushes the error conditions and data
     * from the fifo.
     */
    if (Ser2HSSR0 & (HSSR0_FRE | HSSR0_RAB)) {
        dev->stats.rx_errors++;

        if (Ser2HSSR0 & HSSR0_FRE)
            dev->stats.rx_frame_errors++;

        /*
         * Clear out the DMA...
         */
        Ser2HSCR0 = HSCR0_HSSP;

        /*
         * Clear selected status bits now, so we
         * don't miss them next time around.
         */
        Ser2HSSR0 = HSSR0_FRE | HSSR0_RAB;
    }

    /*
     * Deal with any receive errors.  The any of the lowest
     * 8 bytes in the FIFO may contain an error.  We must read
     * them one by one.  The "error" could even be the end of
     * packet!
     */
    if (Ser2HSSR0 & HSSR0_EIF)
        sa1100_irda_fir_error(si, dev);

    /*
     * No matter what happens, we must restart reception.
     */
    sa1100_irda_rx_dma_start(si);

    return IRQ_HANDLED;
}

/*
 * Set the IrDA communications speed.
 */
static int sa1100_irda_set_speed(struct sa1100_irda *si, int speed)
{
    unsigned long flags;
    int brd, ret = -EINVAL;

    switch (speed) {
    case 9600:  case 19200: case 38400:
    case 57600: case 115200:
        brd = 3686400 / (16 * speed) - 1;

        /* Stop the receive DMA, and configure transmit. */
        if (IS_FIR(si)) {
            dmaengine_terminate_all(si->dma_rx.chan);
            dmaengine_slave_config(si->dma_tx.chan,
                        &sa1100_irda_sir_tx);
        }

        local_irq_save(flags);

        Ser2UTCR3 = 0;
        Ser2HSCR0 = HSCR0_UART;

        Ser2UTCR1 = brd >> 8;
        Ser2UTCR2 = brd;

        /*
         * Clear status register
         */
        Ser2UTSR0 = UTSR0_REB | UTSR0_RBB | UTSR0_RID;
        Ser2UTCR3 = UTCR3_RIE | UTCR3_RXE | UTCR3_TXE;

        if (si->pdata->set_speed)
            si->pdata->set_speed(si->dev, speed);

        si->speed = speed;
        si->tx_start = sa1100_irda_sir_tx_start;
        si->irq = sa1100_irda_sir_irq;

        local_irq_restore(flags);
        ret = 0;
        break;

    case 4000000:
        if (!IS_FIR(si))
            dmaengine_slave_config(si->dma_tx.chan,
                        &sa1100_irda_fir_tx);

        local_irq_save(flags);

        Ser2HSSR0 = 0xff;
        Ser2HSCR0 = HSCR0_HSSP;
        Ser2UTCR3 = 0;

        si->speed = speed;
        si->tx_start = sa1100_irda_fir_tx_start;
        si->irq = sa1100_irda_fir_irq;

        if (si->pdata->set_speed)
            si->pdata->set_speed(si->dev, speed);

        sa1100_irda_rx_alloc(si);
        sa1100_irda_rx_dma_start(si);

        local_irq_restore(flags);

        break;

    default:
        break;
    }

    return ret;
}

/*
 * Control the power state of the IrDA transmitter.
 * State:
 *  0 - off
 *  1 - short range, lowest power
 *  2 - medium range, medium power
 *  3 - maximum range, high power
 *
 * Currently, only assabet is known to support this.
 */
static int
__sa1100_irda_set_power(struct sa1100_irda *si, unsigned int state)
{
    int ret = 0;
    if (si->pdata->set_power)
        ret = si->pdata->set_power(si->dev, state);
    return ret;
}

static inline int
sa1100_set_power(struct sa1100_irda *si, unsigned int state)
{
    int ret;

    ret = __sa1100_irda_set_power(si, state);
    if (ret == 0)
        si->power = state;

    return ret;
}

static irqreturn_t sa1100_irda_irq(int irq, void *dev_id)
{
    struct net_device *dev = dev_id;
    struct sa1100_irda *si = netdev_priv(dev);

    return si->irq(dev, si);
}

static int sa1100_irda_hard_xmit(struct sk_buff *skb, struct net_device *dev)
{
    struct sa1100_irda *si = netdev_priv(dev);
    int speed = irda_get_next_speed(skb);

    /*
     * Does this packet contain a request to change the interface
     * speed?  If so, remember it until we complete the transmission
     * of this frame.
     */
    if (speed != si->speed && speed != -1)
        si->newspeed = speed;

    /* If this is an empty frame, we can bypass a lot. */
    if (skb->len == 0) {
        sa1100_irda_check_speed(si);
        dev_kfree_skb(skb);
        return NETDEV_TX_OK;
    }

    netif_stop_queue(dev);

    /* We must not already have a skb to transmit... */
    BUG_ON(si->dma_tx.skb);

    return si->tx_start(skb, dev, si);
}

static int
sa1100_irda_ioctl(struct net_device *dev, struct ifreq *ifreq, int cmd)
{
    struct if_irda_req *rq = (struct if_irda_req *)ifreq;
    struct sa1100_irda *si = netdev_priv(dev);
    int ret = -EOPNOTSUPP;

    switch (cmd) {
    case SIOCSBANDWIDTH:
        if (capable(CAP_NET_ADMIN)) {
            /*
             * We are unable to set the speed if the
             * device is not running.
             */
            if (si->open) {
                ret = sa1100_irda_set_speed(si,
                        rq->ifr_baudrate);
            } else {
                printk("sa1100_irda_ioctl: SIOCSBANDWIDTH: !netif_running\n");
                ret = 0;
            }
        }
        break;

    case SIOCSMEDIABUSY:
        ret = -EPERM;
        if (capable(CAP_NET_ADMIN)) {
            irda_device_set_media_busy(dev, TRUE);
            ret = 0;
        }
        break;

    case SIOCGRECEIVING:
        rq->ifr_receiving = IS_FIR(si) ? 0
                    : si->rx_buff.state != OUTSIDE_FRAME;
        break;

    default:
        break;
    }
        
    return ret;
}

static int sa1100_irda_startup(struct sa1100_irda *si)
{
    int ret;

    /*
     * Ensure that the ports for this device are setup correctly.
     */
    if (si->pdata->startup) {
        ret = si->pdata->startup(si->dev);
        if (ret)
            return ret;
    }

    /*
     * Configure PPC for IRDA - we want to drive TXD2 low.
     * We also want to drive this pin low during sleep.
     */
    PPSR &= ~PPC_TXD2;
    PSDR &= ~PPC_TXD2;
    PPDR |= PPC_TXD2;

    /*
     * Enable HP-SIR modulation, and ensure that the port is disabled.
     */
    Ser2UTCR3 = 0;
    Ser2HSCR0 = HSCR0_UART;
    Ser2UTCR4 = si->utcr4;
    Ser2UTCR0 = UTCR0_8BitData;
    Ser2HSCR2 = HSCR2_TrDataH | HSCR2_RcDataL;

    /*
     * Clear status register
     */
    Ser2UTSR0 = UTSR0_REB | UTSR0_RBB | UTSR0_RID;

    ret = sa1100_irda_set_speed(si, si->speed = 9600);
    if (ret) {
        Ser2UTCR3 = 0;
        Ser2HSCR0 = 0;

        if (si->pdata->shutdown)
            si->pdata->shutdown(si->dev);
    }

    return ret;
}

static void sa1100_irda_shutdown(struct sa1100_irda *si)
{
    /*
     * Stop all DMA activity.
     */
    dmaengine_terminate_all(si->dma_rx.chan);
    dmaengine_terminate_all(si->dma_tx.chan);

    /* Disable the port. */
    Ser2UTCR3 = 0;
    Ser2HSCR0 = 0;

    if (si->pdata->shutdown)
        si->pdata->shutdown(si->dev);
}

static int sa1100_irda_start(struct net_device *dev)
{
    struct sa1100_irda *si = netdev_priv(dev);
    int err;

    si->speed = 9600;

    err = sa1100_irda_dma_request(si->dev, &si->dma_rx, "Ser2ICPRc",
                &sa1100_irda_fir_rx);
    if (err)
        goto err_rx_dma;

    err = sa1100_irda_dma_request(si->dev, &si->dma_tx, "Ser2ICPTr",
                &sa1100_irda_sir_tx);
    if (err)
        goto err_tx_dma;

    /*
     * Setup the serial port for the specified speed.
     */
    err = sa1100_irda_startup(si);
    if (err)
        goto err_startup;

    /*
     * Open a new IrLAP layer instance.
     */
    si->irlap = irlap_open(dev, &si->qos, "sa1100");
    err = -ENOMEM;
    if (!si->irlap)
        goto err_irlap;

    err = request_irq(dev->irq, sa1100_irda_irq, 0, dev->name, dev);
    if (err)
        goto err_irq;

    /*
     * Now enable the interrupt and start the queue
     */
    si->open = 1;
    sa1100_set_power(si, power_level); /* low power mode */

    netif_start_queue(dev);
    return 0;

err_irq:
    irlap_close(si->irlap);
err_irlap:
    si->open = 0;
    sa1100_irda_shutdown(si);
err_startup:
    dma_release_channel(si->dma_tx.chan);
err_tx_dma:
    dma_release_channel(si->dma_rx.chan);
err_rx_dma:
    return err;
}

static int sa1100_irda_stop(struct net_device *dev)
{
    struct sa1100_irda *si = netdev_priv(dev);
    struct sk_buff *skb;

    netif_stop_queue(dev);

    si->open = 0;
    sa1100_irda_shutdown(si);

    /*
     * If we have been doing any DMA activity, make sure we
     * tidy that up cleanly.
     */
    skb = si->dma_rx.skb;
    if (skb) {
        dma_unmap_sg(si->dma_rx.dev, &si->dma_rx.sg, 1,
                 DMA_FROM_DEVICE);
        dev_kfree_skb(skb);
        si->dma_rx.skb = NULL;
    }

    skb = si->dma_tx.skb;
    if (skb) {
        dma_unmap_sg(si->dma_tx.dev, &si->dma_tx.sg, 1,
                 DMA_TO_DEVICE);
        dev_kfree_skb(skb);
        si->dma_tx.skb = NULL;
    }

    /* Stop IrLAP */
    if (si->irlap) {
        irlap_close(si->irlap);
        si->irlap = NULL;
    }

    /*
     * Free resources
     */
    dma_release_channel(si->dma_tx.chan);
    dma_release_channel(si->dma_rx.chan);
    free_irq(dev->irq, dev);

    sa1100_set_power(si, 0);

    return 0;
}

static int sa1100_irda_init_iobuf(iobuff_t *io, int size)
{
    io->head = kmalloc(size, GFP_KERNEL | GFP_DMA);
    if (io->head != NULL) {
        io->truesize = size;
        io->in_frame = FALSE;
        io->state    = OUTSIDE_FRAME;
        io->data     = io->head;
    }
    return io->head ? 0 : -ENOMEM;
}

static const struct net_device_ops sa1100_irda_netdev_ops = {
    .ndo_open       = sa1100_irda_start,
    .ndo_stop       = sa1100_irda_stop,
    .ndo_start_xmit     = sa1100_irda_hard_xmit,
    .ndo_do_ioctl       = sa1100_irda_ioctl,
};

static int sa1100_irda_probe(struct platform_device *pdev)
{
    struct net_device *dev;
    struct sa1100_irda *si;
    unsigned int baudrate_mask;
    int err, irq;

    if (!pdev->dev.platform_data)
        return -EINVAL;

    irq = platform_get_irq(pdev, 0);
    if (irq <= 0)
        return irq < 0 ? irq : -ENXIO;

    err = request_mem_region(__PREG(Ser2UTCR0), 0x24, "IrDA") ? 0 : -EBUSY;
    if (err)
        goto err_mem_1;
    err = request_mem_region(__PREG(Ser2HSCR0), 0x1c, "IrDA") ? 0 : -EBUSY;
    if (err)
        goto err_mem_2;
    err = request_mem_region(__PREG(Ser2HSCR2), 0x04, "IrDA") ? 0 : -EBUSY;
    if (err)
        goto err_mem_3;

    dev = alloc_irdadev(sizeof(struct sa1100_irda));
    if (!dev) {
        err = -ENOMEM;
        goto err_mem_4;
    }

    SET_NETDEV_DEV(dev, &pdev->dev);

    si = netdev_priv(dev);
    si->dev = &pdev->dev;
    si->pdata = pdev->dev.platform_data;

    sg_init_table(&si->dma_rx.sg, 1);
    sg_init_table(&si->dma_tx.sg, 1);

    /*
     * Initialise the HP-SIR buffers
     */
    err = sa1100_irda_init_iobuf(&si->rx_buff, 14384);
    if (err)
        goto err_mem_5;
    err = sa1100_irda_init_iobuf(&si->tx_buff, IRDA_SIR_MAX_FRAME);
    if (err)
        goto err_mem_5;

    dev->netdev_ops = &sa1100_irda_netdev_ops;
    dev->irq    = irq;

    irda_init_max_qos_capabilies(&si->qos);

    /*
     * We support original IRDA up to 115k2. (we don't currently
     * support 4Mbps).  Min Turn Time set to 1ms or greater.
     */
    baudrate_mask = IR_9600;

    switch (max_rate) {
    case 4000000:       baudrate_mask |= IR_4000000 << 8;
    case 115200:        baudrate_mask |= IR_115200;
    case 57600:     baudrate_mask |= IR_57600;
    case 38400:     baudrate_mask |= IR_38400;
    case 19200:     baudrate_mask |= IR_19200;
    }
        
    si->qos.baud_rate.bits &= baudrate_mask;
    si->qos.min_turn_time.bits = 7;

    irda_qos_bits_to_value(&si->qos);

    si->utcr4 = UTCR4_HPSIR;
    if (tx_lpm)
        si->utcr4 |= UTCR4_Z1_6us;

    /*
     * Initially enable HP-SIR modulation, and ensure that the port
     * is disabled.
     */
    Ser2UTCR3 = 0;
    Ser2UTCR4 = si->utcr4;
    Ser2HSCR0 = HSCR0_UART;

    err = register_netdev(dev);
    if (err == 0)
        platform_set_drvdata(pdev, dev);

    if (err) {
 err_mem_5:
        kfree(si->tx_buff.head);
        kfree(si->rx_buff.head);
        free_netdev(dev);
 err_mem_4:
        release_mem_region(__PREG(Ser2HSCR2), 0x04);
 err_mem_3:
        release_mem_region(__PREG(Ser2HSCR0), 0x1c);
 err_mem_2:
        release_mem_region(__PREG(Ser2UTCR0), 0x24);
    }
 err_mem_1:
    return err;
}

static int sa1100_irda_remove(struct platform_device *pdev)
{
    struct net_device *dev = platform_get_drvdata(pdev);

    if (dev) {
        struct sa1100_irda *si = netdev_priv(dev);
        unregister_netdev(dev);
        kfree(si->tx_buff.head);
        kfree(si->rx_buff.head);
        free_netdev(dev);
    }

    release_mem_region(__PREG(Ser2HSCR2), 0x04);
    release_mem_region(__PREG(Ser2HSCR0), 0x1c);
    release_mem_region(__PREG(Ser2UTCR0), 0x24);

    return 0;
}

#ifdef CONFIG_PM
/*
 * Suspend the IrDA interface.
 */
static int sa1100_irda_suspend(struct platform_device *pdev, pm_message_t state)
{
    struct net_device *dev = platform_get_drvdata(pdev);
    struct sa1100_irda *si;

    if (!dev)
        return 0;

    si = netdev_priv(dev);
    if (si->open) {
        /*
         * Stop the transmit queue
         */
        netif_device_detach(dev);
        disable_irq(dev->irq);
        sa1100_irda_shutdown(si);
        __sa1100_irda_set_power(si, 0);
    }

    return 0;
}

/*
 * Resume the IrDA interface.
 */
static int sa1100_irda_resume(struct platform_device *pdev)
{
    struct net_device *dev = platform_get_drvdata(pdev);
    struct sa1100_irda *si;

    if (!dev)
        return 0;

    si = netdev_priv(dev);
    if (si->open) {
        /*
         * If we missed a speed change, initialise at the new speed
         * directly.  It is debatable whether this is actually
         * required, but in the interests of continuing from where
         * we left off it is desirable.  The converse argument is
         * that we should re-negotiate at 9600 baud again.
         */
        if (si->newspeed) {
            si->speed = si->newspeed;
            si->newspeed = 0;
        }

        sa1100_irda_startup(si);
        __sa1100_irda_set_power(si, si->power);
        enable_irq(dev->irq);

        /*
         * This automatically wakes up the queue
         */
        netif_device_attach(dev);
    }

    return 0;
}
#else
#define sa1100_irda_suspend NULL
#define sa1100_irda_resume  NULL
#endif

static struct platform_driver sa1100ir_driver = {
    .probe      = sa1100_irda_probe,
    .remove     = sa1100_irda_remove,
    .suspend    = sa1100_irda_suspend,
    .resume     = sa1100_irda_resume,
    .driver     = {
        .name   = "sa11x0-ir",
        .owner  = THIS_MODULE,
    },
};

static int __init sa1100_irda_init(void)
{
    /*
     * Limit power level a sensible range.
     */
    if (power_level < 1)
        power_level = 1;
    if (power_level > 3)
        power_level = 3;

    return platform_driver_register(&sa1100ir_driver);
}

static void __exit sa1100_irda_exit(void)
{
    platform_driver_unregister(&sa1100ir_driver);
}

module_init(sa1100_irda_init);
module_exit(sa1100_irda_exit);
module_param(power_level, int, 0);
module_param(tx_lpm, int, 0);
module_param(max_rate, int, 0);

MODULE_AUTHOR("Russell King <[email protected]>");
MODULE_DESCRIPTION("StrongARM SA1100 IrDA driver");
MODULE_LICENSE("GPL");
MODULE_PARM_DESC(power_level, "IrDA power level, 1 (low) to 3 (high)");
MODULE_PARM_DESC(tx_lpm, "Enable transmitter low power (1.6us) mode");
MODULE_PARM_DESC(max_rate, "Maximum baud rate (4000000, 115200, 57600, 38400, 19200, 9600)");
MODULE_ALIAS("platform:sa11x0-ir");