diff options
Diffstat (limited to 'target/linux/generic/patches-3.3/047-spi_message_queue.patch')
| -rw-r--r-- | target/linux/generic/patches-3.3/047-spi_message_queue.patch | 603 |
1 files changed, 0 insertions, 603 deletions
diff --git a/target/linux/generic/patches-3.3/047-spi_message_queue.patch b/target/linux/generic/patches-3.3/047-spi_message_queue.patch deleted file mode 100644 index 9aff0be..0000000 --- a/target/linux/generic/patches-3.3/047-spi_message_queue.patch +++ /dev/null @@ -1,603 +0,0 @@ -commit ffbbdd21329f3e15eeca6df2d4bc11c04d9d91c0 -Author: Linus Walleij <linus.walleij@linaro.org> -Date: Wed Feb 22 10:05:38 2012 +0100 - - spi: create a message queueing infrastructure - - This rips the message queue in the PL022 driver out and pushes - it into (optional) common infrastructure. Drivers that want to - use the message pumping thread will need to define the new - per-messags transfer methods and leave the deprecated transfer() - method as NULL. - - Most of the design is described in the documentation changes that - are included in this patch. - - Since there is a queue that need to be stopped when the system - is suspending/resuming, two new calls are implemented for the - device drivers to call in their suspend()/resume() functions: - spi_master_suspend() and spi_master_resume(). - - ChangeLog v1->v2: - - Remove Kconfig entry and do not make the queue support optional - at all, instead be more agressive and have it as part of the - compulsory infrastructure. - - If the .transfer() method is implemented, delete print a small - deprecation notice and do not start the transfer pump. - - Fix a bitrotted comment. - ChangeLog v2->v3: - - Fix up a problematic sequence courtesy of Chris Blair. - - Stop rather than destroy the queue on suspend() courtesy of - Chris Blair. - - Signed-off-by: Chris Blair <chris.blair@stericsson.com> - Signed-off-by: Linus Walleij <linus.walleij@linaro.org> - Tested-by: Mark Brown <broonie@opensource.wolfsonmicro.com> - Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> - Signed-off-by: Grant Likely <grant.likely@secretlab.ca> - -[Florian: dropped the changes on drivers/spi/spi-pl022.c, removed -the dev_info() about unqueued drivers still using the master function] - ---- a/Documentation/spi/spi-summary -+++ b/Documentation/spi/spi-summary -@@ -1,7 +1,7 @@ - Overview of Linux kernel SPI support - ==================================== - --21-May-2007 -+02-Feb-2012 - - What is SPI? - ------------ -@@ -483,9 +483,9 @@ also initialize its own internal state. - and those methods.) - - After you initialize the spi_master, then use spi_register_master() to --publish it to the rest of the system. At that time, device nodes for --the controller and any predeclared spi devices will be made available, --and the driver model core will take care of binding them to drivers. -+publish it to the rest of the system. At that time, device nodes for the -+controller and any predeclared spi devices will be made available, and -+the driver model core will take care of binding them to drivers. - - If you need to remove your SPI controller driver, spi_unregister_master() - will reverse the effect of spi_register_master(). -@@ -521,21 +521,53 @@ SPI MASTER METHODS - ** When you code setup(), ASSUME that the controller - ** is actively processing transfers for another device. - -- master->transfer(struct spi_device *spi, struct spi_message *message) -- This must not sleep. Its responsibility is arrange that the -- transfer happens and its complete() callback is issued. The two -- will normally happen later, after other transfers complete, and -- if the controller is idle it will need to be kickstarted. -- - master->cleanup(struct spi_device *spi) - Your controller driver may use spi_device.controller_state to hold - state it dynamically associates with that device. If you do that, - be sure to provide the cleanup() method to free that state. - -+ master->prepare_transfer_hardware(struct spi_master *master) -+ This will be called by the queue mechanism to signal to the driver -+ that a message is coming in soon, so the subsystem requests the -+ driver to prepare the transfer hardware by issuing this call. -+ This may sleep. -+ -+ master->unprepare_transfer_hardware(struct spi_master *master) -+ This will be called by the queue mechanism to signal to the driver -+ that there are no more messages pending in the queue and it may -+ relax the hardware (e.g. by power management calls). This may sleep. -+ -+ master->transfer_one_message(struct spi_master *master, -+ struct spi_message *mesg) -+ The subsystem calls the driver to transfer a single message while -+ queuing transfers that arrive in the meantime. When the driver is -+ finished with this message, it must call -+ spi_finalize_current_message() so the subsystem can issue the next -+ transfer. This may sleep. -+ -+ DEPRECATED METHODS -+ -+ master->transfer(struct spi_device *spi, struct spi_message *message) -+ This must not sleep. Its responsibility is arrange that the -+ transfer happens and its complete() callback is issued. The two -+ will normally happen later, after other transfers complete, and -+ if the controller is idle it will need to be kickstarted. This -+ method is not used on queued controllers and must be NULL if -+ transfer_one_message() and (un)prepare_transfer_hardware() are -+ implemented. -+ - - SPI MESSAGE QUEUE - --The bulk of the driver will be managing the I/O queue fed by transfer(). -+If you are happy with the standard queueing mechanism provided by the -+SPI subsystem, just implement the queued methods specified above. Using -+the message queue has the upside of centralizing a lot of code and -+providing pure process-context execution of methods. The message queue -+can also be elevated to realtime priority on high-priority SPI traffic. -+ -+Unless the queueing mechanism in the SPI subsystem is selected, the bulk -+of the driver will be managing the I/O queue fed by the now deprecated -+function transfer(). - - That queue could be purely conceptual. For example, a driver used only - for low-frequency sensor access might be fine using synchronous PIO. -@@ -561,4 +593,6 @@ Stephen Street - Mark Underwood - Andrew Victor - Vitaly Wool -- -+Grant Likely -+Mark Brown -+Linus Walleij ---- a/drivers/spi/spi.c -+++ b/drivers/spi/spi.c -@@ -30,6 +30,9 @@ - #include <linux/of_spi.h> - #include <linux/pm_runtime.h> - #include <linux/export.h> -+#include <linux/sched.h> -+#include <linux/delay.h> -+#include <linux/kthread.h> - - static void spidev_release(struct device *dev) - { -@@ -507,6 +510,293 @@ spi_register_board_info(struct spi_board - - /*-------------------------------------------------------------------------*/ - -+/** -+ * spi_pump_messages - kthread work function which processes spi message queue -+ * @work: pointer to kthread work struct contained in the master struct -+ * -+ * 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. -+ * -+ */ -+static void spi_pump_messages(struct kthread_work *work) -+{ -+ 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 */ -+ spin_lock_irqsave(&master->queue_lock, flags); -+ if (list_empty(&master->queue) || !master->running) { -+ if (master->busy) { -+ ret = master->unprepare_transfer_hardware(master); -+ if (ret) { -+ dev_err(&master->dev, -+ "failed to unprepare transfer hardware\n"); -+ return; -+ } -+ } -+ master->busy = false; -+ spin_unlock_irqrestore(&master->queue_lock, flags); -+ return; -+ } -+ -+ /* Make sure we are not already running a message */ -+ if (master->cur_msg) { -+ spin_unlock_irqrestore(&master->queue_lock, flags); -+ return; -+ } -+ /* Extract head of queue */ -+ master->cur_msg = -+ list_entry(master->queue.next, struct spi_message, queue); -+ -+ list_del_init(&master->cur_msg->queue); -+ if (master->busy) -+ was_busy = true; -+ else -+ master->busy = true; -+ spin_unlock_irqrestore(&master->queue_lock, flags); -+ -+ if (!was_busy) { -+ ret = master->prepare_transfer_hardware(master); -+ if (ret) { -+ dev_err(&master->dev, -+ "failed to prepare transfer hardware\n"); -+ return; -+ } -+ } -+ -+ ret = master->transfer_one_message(master, master->cur_msg); -+ if (ret) { -+ dev_err(&master->dev, -+ "failed to transfer one message from queue\n"); -+ return; -+ } -+} -+ -+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; -+ -+ init_kthread_worker(&master->kworker); -+ master->kworker_task = kthread_run(kthread_worker_fn, -+ &master->kworker, -+ dev_name(&master->dev)); -+ if (IS_ERR(master->kworker_task)) { -+ dev_err(&master->dev, "failed to create message pump task\n"); -+ return -ENOMEM; -+ } -+ init_kthread_work(&master->pump_messages, spi_pump_messages); -+ -+ /* -+ * Master config will indicate if this controller should run the -+ * message pump with high (realtime) priority to reduce the transfer -+ * latency on the bus by minimising the delay between a transfer -+ * request and the scheduling of the message pump thread. Without this -+ * setting the message pump thread will remain at default priority. -+ */ -+ if (master->rt) { -+ dev_info(&master->dev, -+ "will run message pump with realtime priority\n"); -+ sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m); -+ } -+ -+ return 0; -+} -+ -+/** -+ * spi_get_next_queued_message() - called by driver to check for queued -+ * messages -+ * @master: the master to check for queued messages -+ * -+ * If there are more messages in the queue, the next message is returned from -+ * this call. -+ */ -+struct spi_message *spi_get_next_queued_message(struct spi_master *master) -+{ -+ struct spi_message *next; -+ unsigned long flags; -+ -+ /* get a pointer to the next message, if any */ -+ spin_lock_irqsave(&master->queue_lock, flags); -+ if (list_empty(&master->queue)) -+ next = NULL; -+ else -+ next = list_entry(master->queue.next, -+ struct spi_message, queue); -+ spin_unlock_irqrestore(&master->queue_lock, flags); -+ -+ return next; -+} -+EXPORT_SYMBOL_GPL(spi_get_next_queued_message); -+ -+/** -+ * spi_finalize_current_message() - the current message is complete -+ * @master: the master to return the message to -+ * -+ * Called by the driver to notify the core that the message in the front of the -+ * queue is complete and can be removed from the queue. -+ */ -+void spi_finalize_current_message(struct spi_master *master) -+{ -+ struct spi_message *mesg; -+ unsigned long flags; -+ -+ spin_lock_irqsave(&master->queue_lock, flags); -+ mesg = master->cur_msg; -+ master->cur_msg = NULL; -+ -+ queue_kthread_work(&master->kworker, &master->pump_messages); -+ spin_unlock_irqrestore(&master->queue_lock, flags); -+ -+ mesg->state = NULL; -+ if (mesg->complete) -+ mesg->complete(mesg->context); -+} -+EXPORT_SYMBOL_GPL(spi_finalize_current_message); -+ -+static int spi_start_queue(struct spi_master *master) -+{ -+ unsigned long flags; -+ -+ spin_lock_irqsave(&master->queue_lock, flags); -+ -+ if (master->running || master->busy) { -+ spin_unlock_irqrestore(&master->queue_lock, flags); -+ return -EBUSY; -+ } -+ -+ master->running = true; -+ master->cur_msg = NULL; -+ spin_unlock_irqrestore(&master->queue_lock, flags); -+ -+ queue_kthread_work(&master->kworker, &master->pump_messages); -+ -+ return 0; -+} -+ -+static int spi_stop_queue(struct spi_master *master) -+{ -+ unsigned long flags; -+ unsigned limit = 500; -+ int ret = 0; -+ -+ spin_lock_irqsave(&master->queue_lock, flags); -+ -+ /* -+ * This is a bit lame, but is optimized for the common execution path. -+ * A wait_queue on the master->busy could be used, but then the common -+ * execution path (pump_messages) would be required to call wake_up or -+ * friends on every SPI message. Do this instead. -+ */ -+ while ((!list_empty(&master->queue) || master->busy) && limit--) { -+ spin_unlock_irqrestore(&master->queue_lock, flags); -+ msleep(10); -+ spin_lock_irqsave(&master->queue_lock, flags); -+ } -+ -+ if (!list_empty(&master->queue) || master->busy) -+ ret = -EBUSY; -+ else -+ master->running = false; -+ -+ spin_unlock_irqrestore(&master->queue_lock, flags); -+ -+ if (ret) { -+ dev_warn(&master->dev, -+ "could not stop message queue\n"); -+ return ret; -+ } -+ return ret; -+} -+ -+static int spi_destroy_queue(struct spi_master *master) -+{ -+ int ret; -+ -+ ret = spi_stop_queue(master); -+ -+ /* -+ * flush_kthread_worker will block until all work is done. -+ * If the reason that stop_queue timed out is that the work will never -+ * finish, then it does no good to call flush/stop thread, so -+ * return anyway. -+ */ -+ if (ret) { -+ dev_err(&master->dev, "problem destroying queue\n"); -+ return ret; -+ } -+ -+ flush_kthread_worker(&master->kworker); -+ kthread_stop(master->kworker_task); -+ -+ 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) -+{ -+ struct spi_master *master = spi->master; -+ unsigned long flags; -+ -+ spin_lock_irqsave(&master->queue_lock, flags); -+ -+ if (!master->running) { -+ spin_unlock_irqrestore(&master->queue_lock, flags); -+ return -ESHUTDOWN; -+ } -+ msg->actual_length = 0; -+ msg->status = -EINPROGRESS; -+ -+ list_add_tail(&msg->queue, &master->queue); -+ if (master->running && !master->busy) -+ queue_kthread_work(&master->kworker, &master->pump_messages); -+ -+ spin_unlock_irqrestore(&master->queue_lock, flags); -+ return 0; -+} -+ -+static int spi_master_initialize_queue(struct spi_master *master) -+{ -+ int ret; -+ -+ master->queued = true; -+ master->transfer = spi_queued_transfer; -+ -+ /* Initialize and start queue */ -+ ret = spi_init_queue(master); -+ if (ret) { -+ dev_err(&master->dev, "problem initializing queue\n"); -+ goto err_init_queue; -+ } -+ ret = spi_start_queue(master); -+ if (ret) { -+ dev_err(&master->dev, "problem starting queue\n"); -+ goto err_start_queue; -+ } -+ -+ return 0; -+ -+err_start_queue: -+err_init_queue: -+ spi_destroy_queue(master); -+ return ret; -+} -+ -+/*-------------------------------------------------------------------------*/ -+ - static void spi_master_release(struct device *dev) - { - struct spi_master *master; -@@ -522,6 +812,7 @@ static struct class spi_master_class = { - }; - - -+ - /** - * spi_alloc_master - allocate SPI master controller - * @dev: the controller, possibly using the platform_bus -@@ -621,6 +912,15 @@ int spi_register_master(struct spi_maste - dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev), - dynamic ? " (dynamic)" : ""); - -+ /* If we're using a queued driver, start the queue */ -+ if (!master->transfer) { -+ status = spi_master_initialize_queue(master); -+ if (status) { -+ device_unregister(&master->dev); -+ goto done; -+ } -+ } -+ - mutex_lock(&board_lock); - list_add_tail(&master->list, &spi_master_list); - list_for_each_entry(bi, &board_list, list) -@@ -636,7 +936,6 @@ done: - } - EXPORT_SYMBOL_GPL(spi_register_master); - -- - static int __unregister(struct device *dev, void *null) - { - spi_unregister_device(to_spi_device(dev)); -@@ -657,6 +956,11 @@ void spi_unregister_master(struct spi_ma - { - int dummy; - -+ if (master->queued) { -+ if (spi_destroy_queue(master)) -+ dev_err(&master->dev, "queue remove failed\n"); -+ } -+ - mutex_lock(&board_lock); - list_del(&master->list); - mutex_unlock(&board_lock); -@@ -666,6 +970,37 @@ void spi_unregister_master(struct spi_ma - } - EXPORT_SYMBOL_GPL(spi_unregister_master); - -+int spi_master_suspend(struct spi_master *master) -+{ -+ int ret; -+ -+ /* Basically no-ops for non-queued masters */ -+ if (!master->queued) -+ return 0; -+ -+ ret = spi_stop_queue(master); -+ if (ret) -+ dev_err(&master->dev, "queue stop failed\n"); -+ -+ return ret; -+} -+EXPORT_SYMBOL_GPL(spi_master_suspend); -+ -+int spi_master_resume(struct spi_master *master) -+{ -+ int ret; -+ -+ if (!master->queued) -+ return 0; -+ -+ ret = spi_start_queue(master); -+ if (ret) -+ dev_err(&master->dev, "queue restart failed\n"); -+ -+ return ret; -+} -+EXPORT_SYMBOL_GPL(spi_master_resume); -+ - static int __spi_master_match(struct device *dev, void *data) - { - struct spi_master *m; ---- a/include/linux/spi/spi.h -+++ b/include/linux/spi/spi.h -@@ -22,6 +22,7 @@ - #include <linux/device.h> - #include <linux/mod_devicetable.h> - #include <linux/slab.h> -+#include <linux/kthread.h> - - /* - * INTERFACES between SPI master-side drivers and SPI infrastructure. -@@ -235,6 +236,27 @@ static inline void spi_unregister_driver - * the device whose settings are being modified. - * @transfer: adds a message to the controller's transfer queue. - * @cleanup: frees controller-specific state -+ * @queued: whether this master is providing an internal message queue -+ * @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 -+ * @queue_lock: spinlock to syncronise access to message queue -+ * @queue: message queue -+ * @cur_msg: the currently in-flight message -+ * @busy: message pump is busy -+ * @running: message pump is running -+ * @rt: whether this queue is set to run as a realtime task -+ * @prepare_transfer_hardware: a message will soon arrive from the queue -+ * so the subsystem requests the driver to prepare the transfer hardware -+ * by issuing this call -+ * @transfer_one_message: the subsystem calls the driver to transfer a single -+ * message while queuing transfers that arrive in the meantime. When the -+ * driver is finished with this message, it must call -+ * spi_finalize_current_message() so the subsystem can issue the next -+ * transfer -+ * @prepare_transfer_hardware: there are currently no more messages on the -+ * queue so the subsystem notifies the driver that it may relax the -+ * hardware by issuing this call - * - * Each SPI master controller can communicate with one or more @spi_device - * children. These make a small bus, sharing MOSI, MISO and SCK signals -@@ -318,6 +340,28 @@ struct spi_master { - - /* called on release() to free memory provided by spi_master */ - void (*cleanup)(struct spi_device *spi); -+ -+ /* -+ * These hooks are for drivers that want to use the generic -+ * master transfer queueing mechanism. If these are used, the -+ * transfer() function above must NOT be specified by the driver. -+ * Over time we expect SPI drivers to be phased over to this API. -+ */ -+ bool queued; -+ struct kthread_worker kworker; -+ struct task_struct *kworker_task; -+ struct kthread_work pump_messages; -+ spinlock_t queue_lock; -+ struct list_head queue; -+ struct spi_message *cur_msg; -+ bool busy; -+ bool running; -+ bool rt; -+ -+ int (*prepare_transfer_hardware)(struct spi_master *master); -+ int (*transfer_one_message)(struct spi_master *master, -+ struct spi_message *mesg); -+ int (*unprepare_transfer_hardware)(struct spi_master *master); - }; - - static inline void *spi_master_get_devdata(struct spi_master *master) -@@ -343,6 +387,13 @@ static inline void spi_master_put(struct - put_device(&master->dev); - } - -+/* PM calls that need to be issued by the driver */ -+extern int spi_master_suspend(struct spi_master *master); -+extern int spi_master_resume(struct spi_master *master); -+ -+/* Calls the driver make to interact with the message queue */ -+extern struct spi_message *spi_get_next_queued_message(struct spi_master *master); -+extern void spi_finalize_current_message(struct spi_master *master); - - /* the spi driver core manages memory for the spi_master classdev */ - extern struct spi_master * |