diff options
| -rw-r--r-- | drivers/spi/spi.c | 122 | ||||
| -rw-r--r-- | include/linux/spi/spi.h | 2 |
2 files changed, 91 insertions, 33 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 13f447a67d67..06b9139664a3 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1225,7 +1225,7 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread) return; } - /* If another context is idling the device then defer */ + /* If another context is idling the device then defer to kthread */ if (ctlr->idling) { kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages); spin_unlock_irqrestore(&ctlr->queue_lock, flags); @@ -1239,34 +1239,10 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread) return; } - /* Only do teardown in the thread */ - if (!in_kthread) { - kthread_queue_work(&ctlr->kworker, - &ctlr->pump_messages); - spin_unlock_irqrestore(&ctlr->queue_lock, flags); - return; - } - - ctlr->busy = false; - ctlr->idling = true; - spin_unlock_irqrestore(&ctlr->queue_lock, flags); - - kfree(ctlr->dummy_rx); - ctlr->dummy_rx = NULL; - kfree(ctlr->dummy_tx); - ctlr->dummy_tx = NULL; - if (ctlr->unprepare_transfer_hardware && - ctlr->unprepare_transfer_hardware(ctlr)) - dev_err(&ctlr->dev, - "failed to unprepare transfer hardware\n"); - if (ctlr->auto_runtime_pm) { - pm_runtime_mark_last_busy(ctlr->dev.parent); - pm_runtime_put_autosuspend(ctlr->dev.parent); - } - trace_spi_controller_idle(ctlr); - - spin_lock_irqsave(&ctlr->queue_lock, flags); - ctlr->idling = false; + /* schedule idle teardown with a delay of 1 second */ + kthread_mod_delayed_work(&ctlr->kworker, + &ctlr->pump_idle_teardown, + HZ); spin_unlock_irqrestore(&ctlr->queue_lock, flags); return; } @@ -1359,6 +1335,77 @@ static void spi_pump_messages(struct kthread_work *work) __spi_pump_messages(ctlr, true); } +/** + * spi_pump_idle_teardown - kthread delayed work function which tears down + * the controller settings after some delay + * @work: pointer to kthread work struct contained in the controller struct + */ +static void spi_pump_idle_teardown(struct kthread_work *work) +{ + struct spi_controller *ctlr = + container_of(work, struct spi_controller, + pump_idle_teardown.work); + unsigned long flags; + + /* Lock queue */ + spin_lock_irqsave(&ctlr->queue_lock, flags); + + /* Make sure we are not already running a message */ + if (ctlr->cur_msg) + goto out; + + /* if there is anything in the list then exit */ + if (!list_empty(&ctlr->queue)) + goto out; + + /* if the controller is running then exit */ + if (ctlr->running) + goto out; + + /* if the controller is busy then exit */ + if (ctlr->busy) + goto out; + + /* if the controller is idling then exit + * this is actually a bit strange and would indicate that + * this function is scheduled twice, which should not happen + */ + if (ctlr->idling) + goto out; + + /* set up the initial states */ + ctlr->busy = false; + ctlr->idling = true; + spin_unlock_irqrestore(&ctlr->queue_lock, flags); + + /* free dummy receive buffers */ + kfree(ctlr->dummy_rx); + ctlr->dummy_rx = NULL; + kfree(ctlr->dummy_tx); + ctlr->dummy_tx = NULL; + + /* unprepare hardware */ + if (ctlr->unprepare_transfer_hardware && + ctlr->unprepare_transfer_hardware(ctlr)) + dev_err(&ctlr->dev, + "failed to unprepare transfer hardware\n"); + /* handle pm */ + if (ctlr->auto_runtime_pm) { + pm_runtime_mark_last_busy(ctlr->dev.parent); + pm_runtime_put_autosuspend(ctlr->dev.parent); + } + + /* mark controller as idle */ + trace_spi_controller_idle(ctlr); + + /* finally put us from idling into stopped */ + spin_lock_irqsave(&ctlr->queue_lock, flags); + ctlr->idling = false; + +out: + spin_unlock_irqrestore(&ctlr->queue_lock, flags); +} + static int spi_init_queue(struct spi_controller *ctlr) { struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; @@ -1374,7 +1421,8 @@ static int spi_init_queue(struct spi_controller *ctlr) return PTR_ERR(ctlr->kworker_task); } kthread_init_work(&ctlr->pump_messages, spi_pump_messages); - + kthread_init_delayed_work(&ctlr->pump_idle_teardown, + spi_pump_idle_teardown); /* * Controller config will indicate if this controller should run the * message pump with high (realtime) priority to reduce the transfer @@ -1446,7 +1494,16 @@ void spi_finalize_current_message(struct spi_controller *ctlr) spin_lock_irqsave(&ctlr->queue_lock, flags); ctlr->cur_msg = NULL; ctlr->cur_msg_prepared = false; - kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages); + + /* if there is something queued, then wake the queue */ + if (!list_empty(&ctlr->queue)) + kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages); + else + /* otherwise schedule delayed teardown */ + kthread_mod_delayed_work(&ctlr->kworker, + &ctlr->pump_idle_teardown, + HZ); + spin_unlock_irqrestore(&ctlr->queue_lock, flags); trace_spi_message_done(mesg); @@ -1551,7 +1608,7 @@ static int __spi_queued_transfer(struct spi_device *spi, msg->status = -EINPROGRESS; list_add_tail(&msg->queue, &ctlr->queue); - if (!ctlr->busy && need_pump) + if (need_pump) kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages); spin_unlock_irqrestore(&ctlr->queue_lock, flags); @@ -3726,4 +3783,3 @@ err0: * include needing to have boardinfo data structures be much more public. */ postcore_initcall(spi_init); - diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 916bba47d156..79ad62e2487c 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -334,6 +334,7 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * @kworker: thread struct for message pump * @kworker_task: pointer to task for message pump kworker thread * @pump_messages: work struct for scheduling work to the message pump + * @pump_idle_teardown: work structure for scheduling a teardown delayed * @queue_lock: spinlock to syncronise access to message queue * @queue: message queue * @idling: the device is entering idle state @@ -532,6 +533,7 @@ struct spi_controller { struct kthread_worker kworker; struct task_struct *kworker_task; struct kthread_work pump_messages; + struct kthread_delayed_work pump_idle_teardown; spinlock_t queue_lock; struct list_head queue; struct spi_message *cur_msg; |