diff options
Diffstat (limited to 'drivers/spi/spi.c')
| -rw-r--r-- | drivers/spi/spi.c | 120 |
1 files changed, 94 insertions, 26 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 66a70e9bc743..c64a3e59fce3 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -13,10 +13,6 @@ * 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include <linux/kernel.h> @@ -788,7 +784,7 @@ static int spi_transfer_one_message(struct spi_master *master, struct spi_transfer *xfer; bool keep_cs = false; int ret = 0; - int ms = 1; + unsigned long ms = 1; spi_set_cs(msg->spi, true); @@ -875,31 +871,59 @@ void spi_finalize_current_transfer(struct spi_master *master) EXPORT_SYMBOL_GPL(spi_finalize_current_transfer); /** - * spi_pump_messages - kthread work function which processes spi message queue - * @work: pointer to kthread work struct contained in the master struct + * __spi_pump_messages - function which processes spi message queue + * @master: master to process queue for + * @in_kthread: true if we are in the context of the message pump thread * * This function checks if there is any spi message in the queue that * needs processing and if so call out to the driver to initialize hardware * and transfer each message. * + * Note that it is called both from the kthread itself and also from + * inside spi_sync(); the queue extraction handling at the top of the + * function should deal with this safely. */ -static void spi_pump_messages(struct kthread_work *work) +static void __spi_pump_messages(struct spi_master *master, bool in_kthread) { - struct spi_master *master = - container_of(work, struct spi_master, pump_messages); unsigned long flags; bool was_busy = false; int ret; - /* Lock queue and check for queue work */ + /* Lock queue */ spin_lock_irqsave(&master->queue_lock, flags); + + /* Make sure we are not already running a message */ + if (master->cur_msg) { + spin_unlock_irqrestore(&master->queue_lock, flags); + return; + } + + /* If another context is idling the device then defer */ + if (master->idling) { + queue_kthread_work(&master->kworker, &master->pump_messages); + spin_unlock_irqrestore(&master->queue_lock, flags); + return; + } + + /* Check if the queue is idle */ if (list_empty(&master->queue) || !master->running) { if (!master->busy) { spin_unlock_irqrestore(&master->queue_lock, flags); return; } + + /* Only do teardown in the thread */ + if (!in_kthread) { + queue_kthread_work(&master->kworker, + &master->pump_messages); + spin_unlock_irqrestore(&master->queue_lock, flags); + return; + } + master->busy = false; + master->idling = true; spin_unlock_irqrestore(&master->queue_lock, flags); + kfree(master->dummy_rx); master->dummy_rx = NULL; kfree(master->dummy_tx); @@ -913,14 +937,13 @@ static void spi_pump_messages(struct kthread_work *work) pm_runtime_put_autosuspend(master->dev.parent); } trace_spi_master_idle(master); - return; - } - /* Make sure we are not already running a message */ - if (master->cur_msg) { + spin_lock_irqsave(&master->queue_lock, flags); + master->idling = false; spin_unlock_irqrestore(&master->queue_lock, flags); return; } + /* Extract head of queue */ master->cur_msg = list_first_entry(&master->queue, struct spi_message, queue); @@ -985,13 +1008,22 @@ static void spi_pump_messages(struct kthread_work *work) } } +/** + * spi_pump_messages - kthread work function which processes spi message queue + * @work: pointer to kthread work struct contained in the master struct + */ +static void spi_pump_messages(struct kthread_work *work) +{ + struct spi_master *master = + container_of(work, struct spi_master, pump_messages); + + __spi_pump_messages(master, true); +} + static int spi_init_queue(struct spi_master *master) { struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; - INIT_LIST_HEAD(&master->queue); - spin_lock_init(&master->queue_lock); - master->running = false; master->busy = false; @@ -1161,12 +1193,9 @@ static int spi_destroy_queue(struct spi_master *master) return 0; } -/** - * spi_queued_transfer - transfer function for queued transfers - * @spi: spi device which is requesting transfer - * @msg: spi message which is to handled is queued to driver queue - */ -static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg) +static int __spi_queued_transfer(struct spi_device *spi, + struct spi_message *msg, + bool need_pump) { struct spi_master *master = spi->master; unsigned long flags; @@ -1181,13 +1210,23 @@ static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg) msg->status = -EINPROGRESS; list_add_tail(&msg->queue, &master->queue); - if (!master->busy) + if (!master->busy && need_pump) queue_kthread_work(&master->kworker, &master->pump_messages); spin_unlock_irqrestore(&master->queue_lock, flags); return 0; } +/** + * spi_queued_transfer - transfer function for queued transfers + * @spi: spi device which is requesting transfer + * @msg: spi message which is to handled is queued to driver queue + */ +static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg) +{ + return __spi_queued_transfer(spi, msg, true); +} + static int spi_master_initialize_queue(struct spi_master *master) { int ret; @@ -1609,6 +1648,8 @@ int spi_register_master(struct spi_master *master) dynamic = 1; } + INIT_LIST_HEAD(&master->queue); + spin_lock_init(&master->queue_lock); spin_lock_init(&master->bus_lock_spinlock); mutex_init(&master->bus_lock_mutex); master->bus_lock_flag = 0; @@ -2114,19 +2155,46 @@ static int __spi_sync(struct spi_device *spi, struct spi_message *message, DECLARE_COMPLETION_ONSTACK(done); int status; struct spi_master *master = spi->master; + unsigned long flags; + + status = __spi_validate(spi, message); + if (status != 0) + return status; message->complete = spi_complete; message->context = &done; + message->spi = spi; if (!bus_locked) mutex_lock(&master->bus_lock_mutex); - status = spi_async_locked(spi, message); + /* If we're not using the legacy transfer method then we will + * try to transfer in the calling context so special case. + * This code would be less tricky if we could remove the + * support for driver implemented message queues. + */ + if (master->transfer == spi_queued_transfer) { + spin_lock_irqsave(&master->bus_lock_spinlock, flags); + + trace_spi_message_submit(message); + + status = __spi_queued_transfer(spi, message, false); + + spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); + } else { + status = spi_async_locked(spi, message); + } if (!bus_locked) mutex_unlock(&master->bus_lock_mutex); if (status == 0) { + /* Push out the messages in the calling context if we + * can. + */ + if (master->transfer == spi_queued_transfer) + __spi_pump_messages(master, false); + wait_for_completion(&done); status = message->status; } |