CooCenter-System-kernel/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");