Merge tag 'arc-4.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

[deliverable/linux.git] / drivers / net / irda / sa1100_ir.c

/*
 *  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 <linux/platform_data/irda-sa11x0.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",
        },
};

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 <rmk@arm.linux.org.uk>");
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");