[IRDA]: Switching to a workqueue for the SIR work

Since sir_kthread.c pretty much duplicates the workqueue
functionality, we'd better switch.  The SIR fsm has been merged into
sir_dev.c and thus sir_kthread.c is deleted.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Samuel Ortiz <samuel.ortiz@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 311 insertions, 4 deletions

diff --git a/drivers/net/irda/sir_dev.c b/drivers/net/irda/sir_dev.c
index ea7c9464d46a..3b5854d10c17 100644
--- a/drivers/net/irda/sir_dev.c
+++ b/drivers/net/irda/sir_dev.c
@@ -23,6 +23,298 @@
 
 #include "sir-dev.h"
 
+
+static struct workqueue_struct *irda_sir_wq;
+
+/* STATE MACHINE */
+
+/* substate handler of the config-fsm to handle the cases where we want
+ * to wait for transmit completion before changing the port configuration
+ */
+
+static int sirdev_tx_complete_fsm(struct sir_dev *dev)
+{
+        struct sir_fsm *fsm = &dev->fsm;
+        unsigned next_state, delay;
+        unsigned bytes_left;
+
+        do {
+                next_state = fsm->substate;     /* default: stay in current substate */
+                delay = 0;
+
+                switch(fsm->substate) {
+
+                case SIRDEV_STATE_WAIT_XMIT:
+                        if (dev->drv->chars_in_buffer)
+                                bytes_left = dev->drv->chars_in_buffer(dev);
+                        else
+                                bytes_left = 0;
+                        if (!bytes_left) {
+                                next_state = SIRDEV_STATE_WAIT_UNTIL_SENT;
+                                break;
+                        }
+
+                        if (dev->speed > 115200)
+                                delay = (bytes_left*8*10000) / (dev->speed/100);
+                        else if (dev->speed > 0)
+                                delay = (bytes_left*10*10000) / (dev->speed/100);
+                        else
+                                delay = 0;
+                        /* expected delay (usec) until remaining bytes are sent */
+                        if (delay < 100) {
+                                udelay(delay);
+                                delay = 0;
+                                break;
+                        }
+                        /* sleep some longer delay (msec) */
+                        delay = (delay+999) / 1000;
+                        break;
+
+                case SIRDEV_STATE_WAIT_UNTIL_SENT:
+                        /* block until underlaying hardware buffer are empty */
+                        if (dev->drv->wait_until_sent)
+                                dev->drv->wait_until_sent(dev);
+                        next_state = SIRDEV_STATE_TX_DONE;
+                        break;
+
+                case SIRDEV_STATE_TX_DONE:
+                        return 0;
+
+                default:
+                        IRDA_ERROR("%s - undefined state\n", __FUNCTION__);
+                        return -EINVAL;
+                }
+                fsm->substate = next_state;
+        } while (delay == 0);
+        return delay;
+}
+
+/*
+ * Function sirdev_config_fsm
+ *
+ * State machine to handle the configuration of the device (and attached dongle, if any).
+ * This handler is scheduled for execution in kIrDAd context, so we can sleep.
+ * however, kIrDAd is shared by all sir_dev devices so we better don't sleep there too
+ * long. Instead, for longer delays we start a timer to reschedule us later.
+ * On entry, fsm->sem is always locked and the netdev xmit queue stopped.
+ * Both must be unlocked/restarted on completion - but only on final exit.
+ */
+
+static void sirdev_config_fsm(void *data)
+{
+        struct sir_dev *dev = data;
+        struct sir_fsm *fsm = &dev->fsm;
+        int next_state;
+        int ret = -1;
+        unsigned delay;
+
+        IRDA_DEBUG(2, "%s(), <%ld>\n", __FUNCTION__, jiffies);
+
+        do {
+                IRDA_DEBUG(3, "%s - state=0x%04x / substate=0x%04x\n",
+                        __FUNCTION__, fsm->state, fsm->substate);
+
+                next_state = fsm->state;
+                delay = 0;
+
+                switch(fsm->state) {
+
+                case SIRDEV_STATE_DONGLE_OPEN:
+                        if (dev->dongle_drv != NULL) {
+                                ret = sirdev_put_dongle(dev);
+                                if (ret) {
+                                        fsm->result = -EINVAL;
+                                        next_state = SIRDEV_STATE_ERROR;
+                                        break;
+                                }
+                        }
+
+                        /* Initialize dongle */
+                        ret = sirdev_get_dongle(dev, fsm->param);
+                        if (ret) {
+                                fsm->result = ret;
+                                next_state = SIRDEV_STATE_ERROR;
+                                break;
+                        }
+
+                        /* Dongles are powered through the modem control lines which
+                         * were just set during open. Before resetting, let's wait for
+                         * the power to stabilize. This is what some dongle drivers did
+                         * in open before, while others didn't - should be safe anyway.
+                         */
+
+                        delay = 50;
+                        fsm->substate = SIRDEV_STATE_DONGLE_RESET;
+                        next_state = SIRDEV_STATE_DONGLE_RESET;
+
+                        fsm->param = 9600;
+
+                        break;
+
+                case SIRDEV_STATE_DONGLE_CLOSE:
+                        /* shouldn't we just treat this as success=? */
+                        if (dev->dongle_drv == NULL) {
+                                fsm->result = -EINVAL;
+                                next_state = SIRDEV_STATE_ERROR;
+                                break;
+                        }
+
+                        ret = sirdev_put_dongle(dev);
+                        if (ret) {
+                                fsm->result = ret;
+                                next_state = SIRDEV_STATE_ERROR;
+                                break;
+                        }
+                        next_state = SIRDEV_STATE_DONE;
+                        break;
+
+                case SIRDEV_STATE_SET_DTR_RTS:
+                        ret = sirdev_set_dtr_rts(dev,
+                                (fsm->param&0x02) ? TRUE : FALSE,
+                                (fsm->param&0x01) ? TRUE : FALSE);
+                        next_state = SIRDEV_STATE_DONE;
+                        break;
+
+                case SIRDEV_STATE_SET_SPEED:
+                        fsm->substate = SIRDEV_STATE_WAIT_XMIT;
+                        next_state = SIRDEV_STATE_DONGLE_CHECK;
+                        break;
+
+                case SIRDEV_STATE_DONGLE_CHECK:
+                        ret = sirdev_tx_complete_fsm(dev);
+                        if (ret < 0) {
+                                fsm->result = ret;
+                                next_state = SIRDEV_STATE_ERROR;
+                                break;
+                        }
+                        if ((delay=ret) != 0)
+                                break;
+
+                        if (dev->dongle_drv) {
+                                fsm->substate = SIRDEV_STATE_DONGLE_RESET;
+                                next_state = SIRDEV_STATE_DONGLE_RESET;
+                        }
+                        else {
+                                dev->speed = fsm->param;
+                                next_state = SIRDEV_STATE_PORT_SPEED;
+                        }
+                        break;
+
+                case SIRDEV_STATE_DONGLE_RESET:
+                        if (dev->dongle_drv->reset) {
+                                ret = dev->dongle_drv->reset(dev);
+                                if (ret < 0) {
+                                        fsm->result = ret;
+                                        next_state = SIRDEV_STATE_ERROR;
+                                        break;
+                                }
+                        }
+                        else
+                                ret = 0;
+                        if ((delay=ret) == 0) {
+                                /* set serial port according to dongle default speed */
+                                if (dev->drv->set_speed)
+                                        dev->drv->set_speed(dev, dev->speed);
+                                fsm->substate = SIRDEV_STATE_DONGLE_SPEED;
+                                next_state = SIRDEV_STATE_DONGLE_SPEED;
+                        }
+                        break;
+
+                case SIRDEV_STATE_DONGLE_SPEED:
+                        if (dev->dongle_drv->reset) {
+                                ret = dev->dongle_drv->set_speed(dev, fsm->param);
+                                if (ret < 0) {
+                                        fsm->result = ret;
+                                        next_state = SIRDEV_STATE_ERROR;
+                                        break;
+                                }
+                        }
+                        else
+                                ret = 0;
+                        if ((delay=ret) == 0)
+                                next_state = SIRDEV_STATE_PORT_SPEED;
+                        break;
+
+                case SIRDEV_STATE_PORT_SPEED:
+                        /* Finally we are ready to change the serial port speed */
+                        if (dev->drv->set_speed)
+                                dev->drv->set_speed(dev, dev->speed);
+                        dev->new_speed = 0;
+                        next_state = SIRDEV_STATE_DONE;
+                        break;
+
+                case SIRDEV_STATE_DONE:
+                        /* Signal network layer so it can send more frames */
+                        netif_wake_queue(dev->netdev);
+                        next_state = SIRDEV_STATE_COMPLETE;
+                        break;
+
+                default:
+                        IRDA_ERROR("%s - undefined state\n", __FUNCTION__);
+                        fsm->result = -EINVAL;
+                        /* fall thru */
+
+                case SIRDEV_STATE_ERROR:
+                        IRDA_ERROR("%s - error: %d\n", __FUNCTION__, fsm->result);
+
+#if 0   /* don't enable this before we have netdev->tx_timeout to recover */
+                        netif_stop_queue(dev->netdev);
+#else
+                        netif_wake_queue(dev->netdev);
+#endif
+                        /* fall thru */
+
+                case SIRDEV_STATE_COMPLETE:
+                        /* config change finished, so we are not busy any longer */
+                        sirdev_enable_rx(dev);
+                        up(&fsm->sem);
+                        return;
+                }
+                fsm->state = next_state;
+        } while(!delay);
+
+        queue_delayed_work(irda_sir_wq, &fsm->work, msecs_to_jiffies(delay));
+}
+
+/* schedule some device configuration task for execution by kIrDAd
+ * on behalf of the above state machine.
+ * can be called from process or interrupt/tasklet context.
+ */
+
+int sirdev_schedule_request(struct sir_dev *dev, int initial_state, unsigned param)
+{
+        struct sir_fsm *fsm = &dev->fsm;
+
+        IRDA_DEBUG(2, "%s - state=0x%04x / param=%u\n", __FUNCTION__, initial_state, param);
+
+        if (down_trylock(&fsm->sem)) {
+                if (in_interrupt()  ||  in_atomic()  ||  irqs_disabled()) {
+                        IRDA_DEBUG(1, "%s(), state machine busy!\n", __FUNCTION__);
+                        return -EWOULDBLOCK;
+                } else
+                        down(&fsm->sem);
+        }
+
+        if (fsm->state == SIRDEV_STATE_DEAD) {
+                /* race with sirdev_close should never happen */
+                IRDA_ERROR("%s(), instance staled!\n", __FUNCTION__);
+                up(&fsm->sem);
+                return -ESTALE;         /* or better EPIPE? */
+        }
+
+        netif_stop_queue(dev->netdev);
+        atomic_set(&dev->enable_rx, 0);
+
+        fsm->state = initial_state;
+        fsm->param = param;
+        fsm->result = 0;
+
+        INIT_WORK(&fsm->work, sirdev_config_fsm, dev);
+        queue_work(irda_sir_wq, &fsm->work);
+        return 0;
+}
+
+
 /***************************************************************************/
 
 void sirdev_enable_rx(struct sir_dev *dev)
@@ -619,10 +911,6 @@ struct sir_dev * sirdev_get_instance(const struct sir_driver *drv, const char *n
         spin_lock_init(&dev->tx_lock);
         init_MUTEX(&dev->fsm.sem);
 
-        INIT_LIST_HEAD(&dev->fsm.rq.lh_request);
-        dev->fsm.rq.pending = 0;
-        init_timer(&dev->fsm.rq.timer);
-
         dev->drv = drv;
         dev->netdev = ndev;
 
@@ -682,3 +970,22 @@ int sirdev_put_instance(struct sir_dev *dev)
 }
 EXPORT_SYMBOL(sirdev_put_instance);
 
+static int __init sir_wq_init(void)
+{
+        irda_sir_wq = create_singlethread_workqueue("irda_sir_wq");
+        if (!irda_sir_wq)
+                return -ENOMEM;
+        return 0;
+}
+
+static void __exit sir_wq_exit(void)
+{
+        destroy_workqueue(irda_sir_wq);
+}
+
+module_init(sir_wq_init);
+module_exit(sir_wq_exit);
+
+MODULE_AUTHOR("Martin Diehl <info@mdiehl.de>");
+MODULE_DESCRIPTION("IrDA SIR core");
+MODULE_LICENSE("GPL");