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irport.c

/*********************************************************************
 * 
 * Filename:        irport.c
 * Version:   1.0
 * Description:   Half duplex serial port SIR driver for IrDA. 
 * Status:    Experimental.
 * Author:    Dag Brattli <dagb@cs.uit.no>
 * Created at:      Sun Aug  3 13:49:59 1997
 * Modified at:   Fri Jan 28 20:22:38 2000
 * Modified by:   Dag Brattli <dagb@cs.uit.no>
 * Sources:   serial.c by Linus Torvalds 
 * 
 *     Copyright (c) 1997, 1998, 1999-2000 Dag Brattli, All Rights Reserved.
 *     Copyright (c) 2000-2003 Jean Tourrilhes, All Rights Reserved.
 *     
 *     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; if not, write to the Free Software 
 *     Foundation, Inc., 59 Temple Place, Suite 330, Boston, 
 *     MA 02111-1307 USA
 *
 *     This driver is ment to be a small half duplex serial driver to be
 *     used for IR-chipsets that has a UART (16550) compatibility mode. 
 *     Eventually it will replace irtty, because of irtty has some 
 *     problems that is hard to get around when we don't have control
 *     over the serial driver. This driver may also be used by FIR 
 *     drivers to handle SIR mode for them.
 *
 ********************************************************************/

#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <linux/serial_reg.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
#include <linux/rtnetlink.h>
#include <linux/bitops.h>

#include <asm/system.h>
#include <asm/io.h>

#include <net/irda/irda.h>
#include <net/irda/wrapper.h>
#include "irport.h"

#define IO_EXTENT 8

/* 
 * Currently you'll need to set these values using insmod like this:
 * insmod irport io=0x3e8 irq=11
 */
static unsigned int io[]  = { ~0, ~0, ~0, ~0 };
static unsigned int irq[] = { 0, 0, 0, 0 };

static unsigned int qos_mtt_bits = 0x03;

static struct irport_cb *dev_self[] = { NULL, NULL, NULL, NULL};
static char *driver_name = "irport";

static inline void irport_write_wakeup(struct irport_cb *self);
static inline int  irport_write(int iobase, int fifo_size, __u8 *buf, int len);
static inline void irport_receive(struct irport_cb *self);

static int  irport_net_ioctl(struct net_device *dev, struct ifreq *rq, 
                       int cmd);
static inline int  irport_is_receiving(struct irport_cb *self);
static int  irport_set_dtr_rts(struct net_device *dev, int dtr, int rts);
static int  irport_raw_write(struct net_device *dev, __u8 *buf, int len);
static struct net_device_stats *irport_net_get_stats(struct net_device *dev);
static int irport_change_speed_complete(struct irda_task *task);
static void irport_timeout(struct net_device *dev);

static irqreturn_t irport_interrupt(int irq, void *dev_id);
static int irport_hard_xmit(struct sk_buff *skb, struct net_device *dev);
static void irport_change_speed(void *priv, __u32 speed);
static int irport_net_open(struct net_device *dev);
static int irport_net_close(struct net_device *dev);

static struct irport_cb *
irport_open(int i, unsigned int iobase, unsigned int irq)
{
      struct net_device *dev;
      struct irport_cb *self;

      IRDA_DEBUG(1, "%s()\n", __FUNCTION__);

      /* Lock the port that we need */
      if (!request_region(iobase, IO_EXTENT, driver_name)) {
            IRDA_DEBUG(0, "%s(), can't get iobase of 0x%03x\n",
                     __FUNCTION__, iobase);
            goto err_out1;
      }

      /*
       *  Allocate new instance of the driver
       */
      dev = alloc_irdadev(sizeof(struct irport_cb));
      if (!dev) {
            IRDA_ERROR("%s(), can't allocate memory for "
                     "irda device!\n", __FUNCTION__);
            goto err_out2;
      }

      self = dev->priv;
      spin_lock_init(&self->lock);

      /* Need to store self somewhere */
      dev_self[i] = self;
      self->priv = self;
      self->index = i;

      /* Initialize IO */
      self->io.sir_base  = iobase;
        self->io.sir_ext   = IO_EXTENT;
        self->io.irq       = irq;
        self->io.fifo_size = 16;          /* 16550A and compatible */

      /* Initialize QoS for this device */
      irda_init_max_qos_capabilies(&self->qos);
      
      self->qos.baud_rate.bits = IR_9600|IR_19200|IR_38400|IR_57600|
            IR_115200;

      self->qos.min_turn_time.bits = qos_mtt_bits;
      irda_qos_bits_to_value(&self->qos);
      
      /* Bootstrap ZeroCopy Rx */
      self->rx_buff.truesize = IRDA_SKB_MAX_MTU;
      self->rx_buff.skb = __dev_alloc_skb(self->rx_buff.truesize,
                                  GFP_KERNEL);
      if (self->rx_buff.skb == NULL) {
            IRDA_ERROR("%s(), can't allocate memory for "
                     "receive buffer!\n", __FUNCTION__);
            goto err_out3;
      }
      skb_reserve(self->rx_buff.skb, 1);
      self->rx_buff.head = self->rx_buff.skb->data;
      /* No need to memset the buffer, unless you are really pedantic */

      /* Finish setup the Rx buffer descriptor */
      self->rx_buff.in_frame = FALSE;
      self->rx_buff.state = OUTSIDE_FRAME;
      self->rx_buff.data = self->rx_buff.head;

      /* Specify how much memory we want */
      self->tx_buff.truesize = 4000;
      
      /* Allocate memory if needed */
      if (self->tx_buff.truesize > 0) {
            self->tx_buff.head = kzalloc(self->tx_buff.truesize,
                                          GFP_KERNEL);
            if (self->tx_buff.head == NULL) {
                  IRDA_ERROR("%s(), can't allocate memory for "
                           "transmit buffer!\n", __FUNCTION__);
                  goto err_out4;
            }
      }     
      self->tx_buff.data = self->tx_buff.head;

      self->netdev = dev;

      /* May be overridden by piggyback drivers */
      self->interrupt    = irport_interrupt;
      self->change_speed = irport_change_speed;

      /* Override the network functions we need to use */
      dev->hard_start_xmit = irport_hard_xmit;
      dev->tx_timeout        = irport_timeout;
      dev->watchdog_timeo  = HZ;  /* Allow time enough for speed change */
      dev->open            = irport_net_open;
      dev->stop            = irport_net_close;
      dev->get_stats         = irport_net_get_stats;
      dev->do_ioctl        = irport_net_ioctl;

      /* Make ifconfig display some details */
      dev->base_addr = iobase;
      dev->irq = irq;

      if (register_netdev(dev)) {
            IRDA_ERROR("%s(), register_netdev() failed!\n", __FUNCTION__);
            goto err_out5;
      }
      IRDA_MESSAGE("IrDA: Registered device %s (irport io=0x%X irq=%d)\n",
            dev->name, iobase, irq);

      return self;
 err_out5:
      kfree(self->tx_buff.head);
 err_out4:
      kfree_skb(self->rx_buff.skb);
 err_out3:
      free_netdev(dev);
      dev_self[i] = NULL;
 err_out2:
      release_region(iobase, IO_EXTENT);
 err_out1:
      return NULL;
}

static int irport_close(struct irport_cb *self)
{
      IRDA_ASSERT(self != NULL, return -1;);

      /* We are not using any dongle anymore! */
      if (self->dongle)
            irda_device_dongle_cleanup(self->dongle);
      self->dongle = NULL;
      
      /* Remove netdevice */
      unregister_netdev(self->netdev);

      /* Release the IO-port that this driver is using */
      IRDA_DEBUG(0 , "%s(), Releasing Region %03x\n", 
               __FUNCTION__, self->io.sir_base);
      release_region(self->io.sir_base, self->io.sir_ext);

      kfree(self->tx_buff.head);
      
      if (self->rx_buff.skb)
            kfree_skb(self->rx_buff.skb);
      self->rx_buff.skb = NULL;
      
      /* Remove ourselves */
      dev_self[self->index] = NULL;
      free_netdev(self->netdev);
      
      return 0;
}

static void irport_stop(struct irport_cb *self)
{
      int iobase;

      iobase = self->io.sir_base;

      /* We can't lock, we may be called from a FIR driver - Jean II */

      /* We are not transmitting any more */
      self->transmitting = 0;

      /* Reset UART */
      outb(0, iobase+UART_MCR);
      
      /* Turn off interrupts */
      outb(0, iobase+UART_IER);
}

static void irport_start(struct irport_cb *self)
{
      int iobase;

      iobase = self->io.sir_base;

      irport_stop(self);
      
      /* We can't lock, we may be called from a FIR driver - Jean II */

      /* Initialize UART */
      outb(UART_LCR_WLEN8, iobase+UART_LCR);  /* Reset DLAB */
      outb((UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2), iobase+UART_MCR);
      
      /* Turn on interrups */
      outb(UART_IER_RLSI | UART_IER_RDI |UART_IER_THRI, iobase+UART_IER);
}

/*
 * Function irport_get_fcr (speed)
 *
 *    Compute value of fcr
 *
 */
static inline unsigned int irport_get_fcr(__u32 speed)
{
      unsigned int fcr;    /* FIFO control reg */

      /* Enable fifos */
      fcr = UART_FCR_ENABLE_FIFO;

      /* 
       * Use trigger level 1 to avoid 3 ms. timeout delay at 9600 bps, and
       * almost 1,7 ms at 19200 bps. At speeds above that we can just forget
       * about this timeout since it will always be fast enough. 
       */
      if (speed < 38400)
            fcr |= UART_FCR_TRIGGER_1;
      else 
            //fcr |= UART_FCR_TRIGGER_14;
            fcr |= UART_FCR_TRIGGER_8;

      return(fcr);
}
 
/*
 * Function irport_change_speed (self, speed)
 *
 *    Set speed of IrDA port to specified baudrate
 *
 * This function should be called with irq off and spin-lock.
 */
static void irport_change_speed(void *priv, __u32 speed)
{
      struct irport_cb *self = (struct irport_cb *) priv;
      int iobase; 
      unsigned int fcr;    /* FIFO control reg */
      unsigned int lcr;    /* Line control reg */
      int divisor;

      IRDA_ASSERT(self != NULL, return;);
      IRDA_ASSERT(speed != 0, return;);

      IRDA_DEBUG(1, "%s(), Setting speed to: %d - iobase=%#x\n",
                __FUNCTION__, speed, self->io.sir_base);

      /* We can't lock, we may be called from a FIR driver - Jean II */

      iobase = self->io.sir_base;
      
      /* Update accounting for new speed */
      self->io.speed = speed;

      /* Turn off interrupts */
      outb(0, iobase+UART_IER); 

      divisor = SPEED_MAX/speed;
      
      /* Get proper fifo configuration */
      fcr = irport_get_fcr(speed);

      /* IrDA ports use 8N1 */
      lcr = UART_LCR_WLEN8;
      
      outb(UART_LCR_DLAB | lcr, iobase+UART_LCR); /* Set DLAB */
      outb(divisor & 0xff,      iobase+UART_DLL); /* Set speed */
      outb(divisor >> 8,        iobase+UART_DLM);
      outb(lcr,           iobase+UART_LCR); /* Set 8N1      */
      outb(fcr,           iobase+UART_FCR); /* Enable FIFO's */

      /* Turn on interrups */
      /* This will generate a fatal interrupt storm.
       * People calling us will do that properly - Jean II */
      //outb(/*UART_IER_RLSI|*/UART_IER_RDI/*|UART_IER_THRI*/, iobase+UART_IER);
}

/*
 * Function __irport_change_speed (instance, state, param)
 *
 *    State machine for changing speed of the device. We do it this way since
 *    we cannot use schedule_timeout() when we are in interrupt context
 *
 */
static int __irport_change_speed(struct irda_task *task)
{
      struct irport_cb *self;
      __u32 speed = (__u32) task->param;
      unsigned long flags = 0;
      int wasunlocked = 0;
      int ret = 0;

      IRDA_DEBUG(2, "%s(), <%ld>\n", __FUNCTION__, jiffies); 

      self = (struct irport_cb *) task->instance;

      IRDA_ASSERT(self != NULL, return -1;);

      /* Locking notes : this function may be called from irq context with
       * spinlock, via irport_write_wakeup(), or from non-interrupt without
       * spinlock (from the task timer). Yuck !
       * This is ugly, and unsafe is the spinlock is not already acquired.
       * This will be fixed when irda-task get rewritten.
       * Jean II */
      if (!spin_is_locked(&self->lock)) {
            spin_lock_irqsave(&self->lock, flags);
            wasunlocked = 1;
      }

      switch (task->state) {
      case IRDA_TASK_INIT:
      case IRDA_TASK_WAIT:
            /* Are we ready to change speed yet? */
            if (self->tx_buff.len > 0) {
                  task->state = IRDA_TASK_WAIT;

                  /* Try again later */
                  ret = msecs_to_jiffies(20);
                  break;
            }

            if (self->dongle)
                  irda_task_next_state(task, IRDA_TASK_CHILD_INIT);
            else
                  irda_task_next_state(task, IRDA_TASK_CHILD_DONE);
            break;
      case IRDA_TASK_CHILD_INIT:
            /* Go to default speed */
            self->change_speed(self->priv, 9600);

            /* Change speed of dongle */
            if (irda_task_execute(self->dongle,
                              self->dongle->issue->change_speed, 
                              NULL, task, (void *) speed))
            {
                  /* Dongle need more time to change its speed */
                  irda_task_next_state(task, IRDA_TASK_CHILD_WAIT);

                  /* Give dongle 1 sec to finish */
                  ret = msecs_to_jiffies(1000);
            } else
                  /* Child finished immediately */
                  irda_task_next_state(task, IRDA_TASK_CHILD_DONE);
            break;
      case IRDA_TASK_CHILD_WAIT:
            IRDA_WARNING("%s(), changing speed of dongle timed out!\n", __FUNCTION__);
            ret = -1;         
            break;
      case IRDA_TASK_CHILD_DONE:
            /* Finally we are ready to change the speed */
            self->change_speed(self->priv, speed);
            
            irda_task_next_state(task, IRDA_TASK_DONE);
            break;
      default:
            IRDA_ERROR("%s(), unknown state %d\n",
                     __FUNCTION__, task->state);
            irda_task_next_state(task, IRDA_TASK_DONE);
            ret = -1;
            break;
      }
      /* Put stuff in the state we found them - Jean II */
      if(wasunlocked) {
            spin_unlock_irqrestore(&self->lock, flags);
      }

      return ret;
}

/*
 * Function irport_change_speed_complete (task)
 *
 *    Called when the change speed operation completes
 *
 */
static int irport_change_speed_complete(struct irda_task *task)
{
      struct irport_cb *self;

      IRDA_DEBUG(1, "%s()\n", __FUNCTION__);

      self = (struct irport_cb *) task->instance;

      IRDA_ASSERT(self != NULL, return -1;);
      IRDA_ASSERT(self->netdev != NULL, return -1;);

      /* Finished changing speed, so we are not busy any longer */
      /* Signal network layer so it can try to send the frame */

      netif_wake_queue(self->netdev);
      
      return 0;
}

/*
 * Function irport_timeout (struct net_device *dev)
 *
 *    The networking layer thinks we timed out.
 *
 */

static void irport_timeout(struct net_device *dev)
{
      struct irport_cb *self;
      int iobase;
      int iir, lsr;
      unsigned long flags;

      self = (struct irport_cb *) dev->priv;
      IRDA_ASSERT(self != NULL, return;);
      iobase = self->io.sir_base;
      
      IRDA_WARNING("%s: transmit timed out, jiffies = %ld, trans_start = %ld\n",
            dev->name, jiffies, dev->trans_start);
      spin_lock_irqsave(&self->lock, flags);

      /* Debug what's happening... */

      /* Get interrupt status */
      lsr = inb(iobase+UART_LSR);
      /* Read interrupt register */
      iir = inb(iobase+UART_IIR);
      IRDA_DEBUG(0, "%s(), iir=%02x, lsr=%02x, iobase=%#x\n", 
               __FUNCTION__, iir, lsr, iobase);

      IRDA_DEBUG(0, "%s(), transmitting=%d, remain=%d, done=%td\n",
               __FUNCTION__, self->transmitting, self->tx_buff.len,
               self->tx_buff.data - self->tx_buff.head);

      /* Now, restart the port */
      irport_start(self);
      self->change_speed(self->priv, self->io.speed);
      /* This will re-enable irqs */
      outb(/*UART_IER_RLSI|*/UART_IER_RDI/*|UART_IER_THRI*/, iobase+UART_IER);
      dev->trans_start = jiffies;
      spin_unlock_irqrestore(&self->lock, flags);

      netif_wake_queue(dev);
}
 
/*
 * Function irport_wait_hw_transmitter_finish ()
 *
 *    Wait for the real end of HW transmission
 *
 * The UART is a strict FIFO, and we get called only when we have finished
 * pushing data to the FIFO, so the maximum amount of time we must wait
 * is only for the FIFO to drain out.
 *
 * We use a simple calibrated loop. We may need to adjust the loop
 * delay (udelay) to balance I/O traffic and latency. And we also need to
 * adjust the maximum timeout.
 * It would probably be better to wait for the proper interrupt,
 * but it doesn't seem to be available.
 *
 * We can't use jiffies or kernel timers because :
 * 1) We are called from the interrupt handler, which disable softirqs,
 * so jiffies won't be increased
 * 2) Jiffies granularity is usually very coarse (10ms), and we don't
 * want to wait that long to detect stuck hardware.
 * Jean II
 */

static void irport_wait_hw_transmitter_finish(struct irport_cb *self)
{
      int iobase;
      int count = 1000; /* 1 ms */
      
      iobase = self->io.sir_base;

      /* Calibrated busy loop */
      while((count-- > 0) && !(inb(iobase+UART_LSR) & UART_LSR_TEMT))
            udelay(1);

      if(count == 0)
            IRDA_DEBUG(0, "%s(): stuck transmitter\n", __FUNCTION__);
}

/*
 * Function irport_hard_start_xmit (struct sk_buff *skb, struct net_device *dev)
 *
 *    Transmits the current frame until FIFO is full, then
 *    waits until the next transmitt interrupt, and continues until the
 *    frame is transmitted.
 */
static int irport_hard_xmit(struct sk_buff *skb, struct net_device *dev)
{
      struct irport_cb *self;
      unsigned long flags;
      int iobase;
      s32 speed;

      IRDA_DEBUG(1, "%s()\n", __FUNCTION__);

      IRDA_ASSERT(dev != NULL, return 0;);
      
      self = (struct irport_cb *) dev->priv;
      IRDA_ASSERT(self != NULL, return 0;);

      iobase = self->io.sir_base;

      netif_stop_queue(dev);

      /* Make sure tests & speed change are atomic */
      spin_lock_irqsave(&self->lock, flags);

      /* Check if we need to change the speed */
      speed = irda_get_next_speed(skb);
      if ((speed != self->io.speed) && (speed != -1)) {
            /* Check for empty frame */
            if (!skb->len) {
                  /*
                   * We send frames one by one in SIR mode (no
                   * pipelining), so at this point, if we were sending
                   * a previous frame, we just received the interrupt
                   * telling us it is finished (UART_IIR_THRI).
                   * Therefore, waiting for the transmitter to really
                   * finish draining the fifo won't take too long.
                   * And the interrupt handler is not expected to run.
                   * - Jean II */
                  irport_wait_hw_transmitter_finish(self);
                  /* Better go there already locked - Jean II */
                  irda_task_execute(self, __irport_change_speed, 
                                irport_change_speed_complete, 
                                NULL, (void *) speed);
                  dev->trans_start = jiffies;
                  spin_unlock_irqrestore(&self->lock, flags);
                  dev_kfree_skb(skb);
                  return 0;
            } else
                  self->new_speed = speed;
      }

      /* Init tx buffer */
      self->tx_buff.data = self->tx_buff.head;

        /* Copy skb to tx_buff while wrapping, stuffing and making CRC */
      self->tx_buff.len = async_wrap_skb(skb, self->tx_buff.data, 
                                 self->tx_buff.truesize);
      
      self->stats.tx_bytes += self->tx_buff.len;

      /* We are transmitting */
      self->transmitting = 1;

      /* Turn on transmit finished interrupt. Will fire immediately!  */
      outb(UART_IER_THRI, iobase+UART_IER); 

      dev->trans_start = jiffies;
      spin_unlock_irqrestore(&self->lock, flags);

      dev_kfree_skb(skb);
      
      return 0;
}
        
/*
 * Function irport_write (driver)
 *
 *    Fill Tx FIFO with transmit data
 *
 * Called only from irport_write_wakeup()
 */
static inline int irport_write(int iobase, int fifo_size, __u8 *buf, int len)
{
      int actual = 0;

      /* Fill FIFO with current frame */
      while ((actual < fifo_size) && (actual < len)) {
            /* Transmit next byte */
            outb(buf[actual], iobase+UART_TX);

            actual++;
      }
        
      return actual;
}

/*
 * Function irport_write_wakeup (tty)
 *
 *    Called by the driver when there's room for more data.  If we have
 *    more packets to send, we send them here.
 *
 * Called only from irport_interrupt()
 * Make sure this function is *not* called while we are receiving,
 * otherwise we will reset fifo and loose data :-(
 */
static inline void irport_write_wakeup(struct irport_cb *self)
{
      int actual = 0;
      int iobase;
      unsigned int fcr;

      IRDA_ASSERT(self != NULL, return;);

      IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

      iobase = self->io.sir_base;

      /* Finished with frame?  */
      if (self->tx_buff.len > 0)  {
            /* Write data left in transmit buffer */
            actual = irport_write(iobase, self->io.fifo_size, 
                              self->tx_buff.data, self->tx_buff.len);
            self->tx_buff.data += actual;
            self->tx_buff.len  -= actual;
      } else {
            /* 
             *  Now serial buffer is almost free & we can start 
             *  transmission of another packet. But first we must check
             *  if we need to change the speed of the hardware
             */
            if (self->new_speed) {
                  irport_wait_hw_transmitter_finish(self);
                  irda_task_execute(self, __irport_change_speed, 
                                irport_change_speed_complete, 
                                NULL, (void *) self->new_speed);
                  self->new_speed = 0;
            } else {
                  /* Tell network layer that we want more frames */
                  netif_wake_queue(self->netdev);
            }
            self->stats.tx_packets++;

            /* 
             * Reset Rx FIFO to make sure that all reflected transmit data
             * is discarded. This is needed for half duplex operation
             */
            fcr = irport_get_fcr(self->io.speed);
            fcr |= UART_FCR_CLEAR_RCVR;
            outb(fcr, iobase+UART_FCR);

            /* Finished transmitting */
            self->transmitting = 0;

            /* Turn on receive interrupts */
            outb(UART_IER_RDI, iobase+UART_IER);

            IRDA_DEBUG(1, "%s() : finished Tx\n", __FUNCTION__);
      }
}

/*
 * Function irport_receive (self)
 *
 *    Receive one frame from the infrared port
 *
 * Called only from irport_interrupt()
 */
static inline void irport_receive(struct irport_cb *self) 
{
      int boguscount = 0;
      int iobase;

      IRDA_ASSERT(self != NULL, return;);

      iobase = self->io.sir_base;

      /*  
       * Receive all characters in Rx FIFO, unwrap and unstuff them. 
         * async_unwrap_char will deliver all found frames  
       */
      do {
            async_unwrap_char(self->netdev, &self->stats, &self->rx_buff, 
                          inb(iobase+UART_RX));

            /* Make sure we don't stay here too long */
            if (boguscount++ > 32) {
                  IRDA_DEBUG(2,"%s(), breaking!\n", __FUNCTION__);
                  break;
            }
      } while (inb(iobase+UART_LSR) & UART_LSR_DR);   
}

/*
 * Function irport_interrupt (irq, dev_id)
 *
 *    Interrupt handler
 */
static irqreturn_t irport_interrupt(int irq, void *dev_id) 
{
      struct net_device *dev = dev_id;
      struct irport_cb *self;
      int boguscount = 0;
      int iobase;
      int iir, lsr;
      int handled = 0;

      self = dev->priv;

      spin_lock(&self->lock);

      iobase = self->io.sir_base;

      /* Cut'n'paste interrupt routine from serial.c
       * This version try to minimise latency and I/O operations.
       * Simplified and modified to enforce half duplex operation.
       * - Jean II */

      /* Check status even is iir reg is cleared, more robust and
       * eliminate a read on the I/O bus - Jean II */
      do {
            /* Get interrupt status ; Clear interrupt */
            lsr = inb(iobase+UART_LSR);
            
            /* Are we receiving or transmitting ? */
            if(!self->transmitting) {
                  /* Received something ? */
                  if (lsr & UART_LSR_DR)
                        irport_receive(self);
            } else {
                  /* Room in Tx fifo ? */
                  if (lsr & (UART_LSR_THRE | UART_LSR_TEMT))
                        irport_write_wakeup(self);
            }

            /* A bit hackish, but working as expected... Jean II */
            if(lsr & (UART_LSR_THRE | UART_LSR_TEMT | UART_LSR_DR))
                  handled = 1;

            /* Make sure we don't stay here to long */
            if (boguscount++ > 10) {
                  IRDA_WARNING("%s() irq handler looping : lsr=%02x\n",
                             __FUNCTION__, lsr);
                  break;
            }

            /* Read interrupt register */
              iir = inb(iobase+UART_IIR);

            /* Enable this debug only when no other options and at low
             * bit rates, otherwise it may cause Rx overruns (lsr=63).
             * - Jean II */
            IRDA_DEBUG(6, "%s(), iir=%02x, lsr=%02x, iobase=%#x\n", 
                      __FUNCTION__, iir, lsr, iobase);

            /* As long as interrupt pending... */
      } while ((iir & UART_IIR_NO_INT) == 0);

      spin_unlock(&self->lock);
      return IRQ_RETVAL(handled);
}

/*
 * Function irport_net_open (dev)
 *
 *    Network device is taken up. Usually this is done by "ifconfig irda0 up" 
 *   
 */
static int irport_net_open(struct net_device *dev)
{
      struct irport_cb *self;
      int iobase;
      char hwname[16];
      unsigned long flags;

      IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

      IRDA_ASSERT(dev != NULL, return -1;);
      self = (struct irport_cb *) dev->priv;

      iobase = self->io.sir_base;

      if (request_irq(self->io.irq, self->interrupt, 0, dev->name, 
                  (void *) dev)) {
            IRDA_DEBUG(0, "%s(), unable to allocate irq=%d\n",
                     __FUNCTION__, self->io.irq);
            return -EAGAIN;
      }

      spin_lock_irqsave(&self->lock, flags);
      /* Init uart */
      irport_start(self);
      /* Set 9600 bauds per default, including at the dongle */
      irda_task_execute(self, __irport_change_speed, 
                    irport_change_speed_complete, 
                    NULL, (void *) 9600);
      spin_unlock_irqrestore(&self->lock, flags);


      /* Give self a hardware name */
      sprintf(hwname, "SIR @ 0x%03x", self->io.sir_base);

      /* 
       * Open new IrLAP layer instance, now that everything should be
       * initialized properly 
       */
      self->irlap = irlap_open(dev, &self->qos, hwname);

      /* Ready to play! */

      netif_start_queue(dev);

      return 0;
}

/*
 * Function irport_net_close (self)
 *
 *    Network device is taken down. Usually this is done by 
 *    "ifconfig irda0 down" 
 */
static int irport_net_close(struct net_device *dev)
{
      struct irport_cb *self;
      int iobase;
      unsigned long flags;

      IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

      IRDA_ASSERT(dev != NULL, return -1;);
      self = (struct irport_cb *) dev->priv;

      IRDA_ASSERT(self != NULL, return -1;);

      iobase = self->io.sir_base;

      /* Stop device */
      netif_stop_queue(dev);
      
      /* Stop and remove instance of IrLAP */
      if (self->irlap)
            irlap_close(self->irlap);
      self->irlap = NULL;

      spin_lock_irqsave(&self->lock, flags);
      irport_stop(self);
      spin_unlock_irqrestore(&self->lock, flags);

      free_irq(self->io.irq, dev);

      return 0;
}

/*
 * Function irport_is_receiving (self)
 *
 *    Returns true is we are currently receiving data
 *
 */
static inline int irport_is_receiving(struct irport_cb *self)
{
      return (self->rx_buff.state != OUTSIDE_FRAME);
}

/*
 * Function irport_set_dtr_rts (tty, dtr, rts)
 *
 *    This function can be used by dongles etc. to set or reset the status
 *    of the dtr and rts lines
 */
static int irport_set_dtr_rts(struct net_device *dev, int dtr, int rts)
{
      struct irport_cb *self = dev->priv;
      int iobase;

      IRDA_ASSERT(self != NULL, return -1;);

      iobase = self->io.sir_base;

      if (dtr)
            dtr = UART_MCR_DTR;
      if (rts)
            rts = UART_MCR_RTS;

      outb(dtr|rts|UART_MCR_OUT2, iobase+UART_MCR);

      return 0;
}

static int irport_raw_write(struct net_device *dev, __u8 *buf, int len)
{
      struct irport_cb *self = (struct irport_cb *) dev->priv;
      int actual = 0;
      int iobase;

      IRDA_ASSERT(self != NULL, return -1;);

      iobase = self->io.sir_base;

      /* Tx FIFO should be empty! */
      if (!(inb(iobase+UART_LSR) & UART_LSR_THRE)) {
            IRDA_DEBUG( 0, "%s(), failed, fifo not empty!\n", __FUNCTION__);
            return -1;
      }
        
      /* Fill FIFO with current frame */
      while (actual < len) {
            /* Transmit next byte */
            outb(buf[actual], iobase+UART_TX);
            actual++;
      }

      return actual;
}

/*
 * Function irport_net_ioctl (dev, rq, cmd)
 *
 *    Process IOCTL commands for this device
 *
 */
static int irport_net_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
      struct if_irda_req *irq = (struct if_irda_req *) rq;
      struct irport_cb *self;
      dongle_t *dongle;
      unsigned long flags;
      int ret = 0;

      IRDA_ASSERT(dev != NULL, return -1;);

      self = dev->priv;

      IRDA_ASSERT(self != NULL, return -1;);

      IRDA_DEBUG(2, "%s(), %s, (cmd=0x%X)\n", __FUNCTION__, dev->name, cmd);
      
      switch (cmd) {
      case SIOCSBANDWIDTH: /* Set bandwidth */
            if (!capable(CAP_NET_ADMIN))
                  ret = -EPERM;
                else
                  irda_task_execute(self, __irport_change_speed, NULL, 
                                NULL, (void *) irq->ifr_baudrate);
            break;
      case SIOCSDONGLE: /* Set dongle */
            if (!capable(CAP_NET_ADMIN)) {
                  ret = -EPERM;
                  break;
            }

            /* Locking :
             * irda_device_dongle_init() can't be locked.
             * irda_task_execute() doesn't need to be locked.
             * Jean II
             */

            /* Initialize dongle */
            dongle = irda_device_dongle_init(dev, irq->ifr_dongle);
            if (!dongle)
                  break;
            
            dongle->set_mode    = NULL;
            dongle->read        = NULL;
            dongle->write       = irport_raw_write;
            dongle->set_dtr_rts = irport_set_dtr_rts;
            
            /* Now initialize the dongle!  */
            dongle->issue->open(dongle, &self->qos);
            
            /* Reset dongle */
            irda_task_execute(dongle, dongle->issue->reset, NULL, NULL, 
                          NULL);    

            /* Make dongle available to driver only now to avoid
             * race conditions - Jean II */
            self->dongle = dongle;
            break;
      case SIOCSMEDIABUSY: /* Set media busy */
            if (!capable(CAP_NET_ADMIN)) {
                  ret = -EPERM;
                  break;
            }

            irda_device_set_media_busy(self->netdev, TRUE);
            break;
      case SIOCGRECEIVING: /* Check if we are receiving right now */
            irq->ifr_receiving = irport_is_receiving(self);
            break;
      case SIOCSDTRRTS:
            if (!capable(CAP_NET_ADMIN)) {
                  ret = -EPERM;
                  break;
            }

            /* No real need to lock... */
            spin_lock_irqsave(&self->lock, flags);
            irport_set_dtr_rts(dev, irq->ifr_dtr, irq->ifr_rts);
            spin_unlock_irqrestore(&self->lock, flags);
            break;
      default:
            ret = -EOPNOTSUPP;
      }
      
      return ret;
}

static struct net_device_stats *irport_net_get_stats(struct net_device *dev)
{
      struct irport_cb *self = (struct irport_cb *) dev->priv;
      
      return &self->stats;
}

static int __init irport_init(void)
{
      int i;

      for (i=0; (io[i] < 2000) && (i < ARRAY_SIZE(dev_self)); i++) {
            if (irport_open(i, io[i], irq[i]) != NULL)
                  return 0;
      }
      /* 
       * Maybe something failed, but we can still be usable for FIR drivers 
       */
      return 0;
}

/*
 * Function irport_cleanup ()
 *
 *    Close all configured ports
 *
 */
static void __exit irport_cleanup(void)
{
      int i;

        IRDA_DEBUG( 4, "%s()\n", __FUNCTION__);

      for (i=0; i < ARRAY_SIZE(dev_self); i++) {
            if (dev_self[i])
                  irport_close(dev_self[i]);
      }
}

module_param_array(io, int, NULL, 0);
MODULE_PARM_DESC(io, "Base I/O addresses");
module_param_array(irq, int, NULL, 0);
MODULE_PARM_DESC(irq, "IRQ lines");

MODULE_AUTHOR("Dag Brattli <dagb@cs.uit.no>");
MODULE_DESCRIPTION("Half duplex serial driver for IrDA SIR mode");
MODULE_LICENSE("GPL");

module_init(irport_init);
module_exit(irport_cleanup);


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