diff options
| -rw-r--r-- | Documentation/spi/spi-summary | 58 | ||||
| -rw-r--r-- | drivers/spi/spi-pl022.c | 303 | ||||
| -rw-r--r-- | drivers/spi/spi.c | 339 | ||||
| -rw-r--r-- | include/linux/spi/spi.h | 51 |
4 files changed, 487 insertions, 264 deletions
diff --git a/Documentation/spi/spi-summary b/Documentation/spi/spi-summary index 4884cb33845d..7312ec14dd89 100644 --- 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. (See below about bus numbering 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 diff --git a/drivers/spi/spi-pl022.c b/drivers/spi/spi-pl022.c index 81847c9a7586..ec17a7af7e28 100644 --- a/drivers/spi/spi-pl022.c +++ b/drivers/spi/spi-pl022.c @@ -29,7 +29,6 @@ #include <linux/errno.h> #include <linux/interrupt.h> #include <linux/spi/spi.h> -#include <linux/kthread.h> #include <linux/delay.h> #include <linux/clk.h> #include <linux/err.h> @@ -41,7 +40,6 @@ #include <linux/dma-mapping.h> #include <linux/scatterlist.h> #include <linux/pm_runtime.h> -#include <linux/sched.h> /* * This macro is used to define some register default values. @@ -367,15 +365,7 @@ struct pl022 { struct clk *clk; struct spi_master *master; struct pl022_ssp_controller *master_info; - /* Driver message pump */ - struct kthread_worker kworker; - struct task_struct *kworker_task; - struct kthread_work pump_messages; - spinlock_t queue_lock; - struct list_head queue; - bool busy; - bool running; - /* Message transfer pump */ + /* Message per-transfer pump */ struct tasklet_struct pump_transfers; struct spi_message *cur_msg; struct spi_transfer *cur_transfer; @@ -397,6 +387,7 @@ struct pl022 { struct sg_table sgt_rx; struct sg_table sgt_tx; char *dummypage; + bool dma_running; #endif }; @@ -451,8 +442,6 @@ static void null_cs_control(u32 command) static void giveback(struct pl022 *pl022) { struct spi_transfer *last_transfer; - unsigned long flags; - struct spi_message *msg; pl022->next_msg_cs_active = false; last_transfer = list_entry(pl022->cur_msg->transfers.prev, @@ -480,15 +469,8 @@ static void giveback(struct pl022 *pl022) * sent the current message could be unloaded, which * could invalidate the cs_control() callback... */ - /* get a pointer to the next message, if any */ - spin_lock_irqsave(&pl022->queue_lock, flags); - if (list_empty(&pl022->queue)) - next_msg = NULL; - else - next_msg = list_entry(pl022->queue.next, - struct spi_message, queue); - spin_unlock_irqrestore(&pl022->queue_lock, flags); + next_msg = spi_get_next_queued_message(pl022->master); /* * see if the next and current messages point @@ -500,19 +482,13 @@ static void giveback(struct pl022 *pl022) pl022->cur_chip->cs_control(SSP_CHIP_DESELECT); else pl022->next_msg_cs_active = true; + } - spin_lock_irqsave(&pl022->queue_lock, flags); - msg = pl022->cur_msg; pl022->cur_msg = NULL; pl022->cur_transfer = NULL; pl022->cur_chip = NULL; - queue_kthread_work(&pl022->kworker, &pl022->pump_messages); - spin_unlock_irqrestore(&pl022->queue_lock, flags); - - msg->state = NULL; - if (msg->complete) - msg->complete(msg->context); + spi_finalize_current_message(pl022->master); } /** @@ -1066,6 +1042,7 @@ static int configure_dma(struct pl022 *pl022) dmaengine_submit(txdesc); dma_async_issue_pending(rxchan); dma_async_issue_pending(txchan); + pl022->dma_running = true; return 0; @@ -1144,11 +1121,12 @@ static void terminate_dma(struct pl022 *pl022) dmaengine_terminate_all(rxchan); dmaengine_terminate_all(txchan); unmap_free_dma_scatter(pl022); + pl022->dma_running = false; } static void pl022_dma_remove(struct pl022 *pl022) { - if (pl022->busy) + if (pl022->dma_running) terminate_dma(pl022); if (pl022->dma_tx_channel) dma_release_channel(pl022->dma_tx_channel); @@ -1496,73 +1474,20 @@ out: return; } -/** - * pump_messages - kthread work function which processes spi message queue - * @work: pointer to kthread work struct contained in the pl022 private struct - * - * This function checks if there is any spi message in the queue that - * needs processing and delegate control to appropriate function - * do_polling_transfer()/do_interrupt_dma_transfer() - * based on the kind of the transfer - * - */ -static void pump_messages(struct kthread_work *work) +static int pl022_transfer_one_message(struct spi_master *master, + struct spi_message *msg) { - struct pl022 *pl022 = - container_of(work, struct pl022, pump_messages); - unsigned long flags; - bool was_busy = false; - - /* Lock queue and check for queue work */ - spin_lock_irqsave(&pl022->queue_lock, flags); - if (list_empty(&pl022->queue) || !pl022->running) { - if (pl022->busy) { - /* nothing more to do - disable spi/ssp and power off */ - writew((readw(SSP_CR1(pl022->virtbase)) & - (~SSP_CR1_MASK_SSE)), SSP_CR1(pl022->virtbase)); - - if (pl022->master_info->autosuspend_delay > 0) { - pm_runtime_mark_last_busy(&pl022->adev->dev); - pm_runtime_put_autosuspend(&pl022->adev->dev); - } else { - pm_runtime_put(&pl022->adev->dev); - } - } - pl022->busy = false; - spin_unlock_irqrestore(&pl022->queue_lock, flags); - return; - } - - /* Make sure we are not already running a message */ - if (pl022->cur_msg) { - spin_unlock_irqrestore(&pl022->queue_lock, flags); - return; - } - /* Extract head of queue */ - pl022->cur_msg = - list_entry(pl022->queue.next, struct spi_message, queue); - - list_del_init(&pl022->cur_msg->queue); - if (pl022->busy) - was_busy = true; - else - pl022->busy = true; - spin_unlock_irqrestore(&pl022->queue_lock, flags); + struct pl022 *pl022 = spi_master_get_devdata(master); /* Initial message state */ - pl022->cur_msg->state = STATE_START; - pl022->cur_transfer = list_entry(pl022->cur_msg->transfers.next, - struct spi_transfer, transfer_list); + pl022->cur_msg = msg; + msg->state = STATE_START; + + pl022->cur_transfer = list_entry(msg->transfers.next, + struct spi_transfer, transfer_list); /* Setup the SPI using the per chip configuration */ - pl022->cur_chip = spi_get_ctldata(pl022->cur_msg->spi); - if (!was_busy) - /* - * We enable the core voltage and clocks here, then the clocks - * and core will be disabled when this thread is run again - * and there is no more work to be done. - */ - pm_runtime_get_sync(&pl022->adev->dev); + pl022->cur_chip = spi_get_ctldata(msg->spi); restore_state(pl022); flush(pl022); @@ -1571,119 +1496,37 @@ static void pump_messages(struct kthread_work *work) do_polling_transfer(pl022); else do_interrupt_dma_transfer(pl022); -} - -static int __init init_queue(struct pl022 *pl022) -{ - struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; - - INIT_LIST_HEAD(&pl022->queue); - spin_lock_init(&pl022->queue_lock); - - pl022->running = false; - pl022->busy = false; - - tasklet_init(&pl022->pump_transfers, pump_transfers, - (unsigned long)pl022); - - init_kthread_worker(&pl022->kworker); - pl022->kworker_task = kthread_run(kthread_worker_fn, - &pl022->kworker, - dev_name(pl022->master->dev.parent)); - if (IS_ERR(pl022->kworker_task)) { - dev_err(&pl022->adev->dev, - "failed to create message pump task\n"); - return -ENOMEM; - } - init_kthread_work(&pl022->pump_messages, pump_messages); - - /* - * Board 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 (pl022->master_info->rt) { - dev_info(&pl022->adev->dev, - "will run message pump with realtime priority\n"); - sched_setscheduler(pl022->kworker_task, SCHED_FIFO, ¶m); - } return 0; } -static int start_queue(struct pl022 *pl022) +static int pl022_prepare_transfer_hardware(struct spi_master *master) { - unsigned long flags; - - spin_lock_irqsave(&pl022->queue_lock, flags); - - if (pl022->running || pl022->busy) { - spin_unlock_irqrestore(&pl022->queue_lock, flags); - return -EBUSY; - } - - pl022->running = true; - pl022->cur_msg = NULL; - pl022->cur_transfer = NULL; - pl022->cur_chip = NULL; - pl022->next_msg_cs_active = false; - spin_unlock_irqrestore(&pl022->queue_lock, flags); - - queue_kthread_work(&pl022->kworker, &pl022->pump_messages); + struct pl022 *pl022 = spi_master_get_devdata(master); + /* + * Just make sure we have all we need to run the transfer by syncing + * with the runtime PM framework. + */ + pm_runtime_get_sync(&pl022->adev->dev); return 0; } -static int stop_queue(struct pl022 *pl022) +static int pl022_unprepare_transfer_hardware(struct spi_master *master) { - unsigned long flags; - unsigned limit = 500; - int status = 0; + struct pl022 *pl022 = spi_master_get_devdata(master); - spin_lock_irqsave(&pl022->queue_lock, flags); + /* nothing more to do - disable spi/ssp and power off */ + writew((readw(SSP_CR1(pl022->virtbase)) & + (~SSP_CR1_MASK_SSE)), SSP_CR1(pl022->virtbase)); - /* This is a bit lame, but is optimized for the common execution path. - * A wait_queue on the pl022->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(&pl022->queue) || pl022->busy) && limit--) { - spin_unlock_irqrestore(&pl022->queue_lock, flags); - msleep(10); - spin_lock_irqsave(&pl022->queue_lock, flags); + if (pl022->master_info->autosuspend_delay > 0) { + pm_runtime_mark_last_busy(&pl022->adev->dev); + pm_runtime_put_autosuspend(&pl022->adev->dev); + } else { + pm_runtime_put(&pl022->adev->dev); } - if (!list_empty(&pl022->queue) || pl022->busy) - status = -EBUSY; - else - pl022->running = false; - - spin_unlock_irqrestore(&pl022->queue_lock, flags); - - return status; -} - -static int destroy_queue(struct pl022 *pl022) -{ - int status; - - status = stop_queue(pl022); - - /* - * We are unloading the module or failing to load (only two calls - * to this routine), and neither call can handle a return value. - * However, 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 (status != 0) - return status; - - flush_kthread_worker(&pl022->kworker); - kthread_stop(pl022->kworker_task); - return 0; } @@ -1803,38 +1646,6 @@ static int verify_controller_parameters(struct pl022 *pl022, return 0; } -/** - * pl022_transfer - transfer function registered to SPI master framework - * @spi: spi device which is requesting transfer - * @msg: spi message which is to handled is queued to driver queue - * - * This function is registered to the SPI framework for this SPI master - * controller. It will queue the spi_message in the queue of driver if - * the queue is not stopped and return. - */ -static int pl022_transfer(struct spi_device *spi, struct spi_message *msg) -{ - struct pl022 *pl022 = spi_master_get_devdata(spi->master); - unsigned long flags; - - spin_lock_irqsave(&pl022->queue_lock, flags); - - if (!pl022->running) { - spin_unlock_irqrestore(&pl022->queue_lock, flags); - return -ESHUTDOWN; - } - msg->actual_length = 0; - msg->status = -EINPROGRESS; - msg->state = STATE_START; - - list_add_tail(&msg->queue, &pl022->queue); - if (pl022->running && !pl022->busy) - queue_kthread_work(&pl022->kworker, &pl022->pump_messages); - - spin_unlock_irqrestore(&pl022->queue_lock, flags); - return 0; -} - static inline u32 spi_rate(u32 rate, u16 cpsdvsr, u16 scr) { return rate / (cpsdvsr * (1 + scr)); @@ -2197,7 +2008,10 @@ pl022_probe(struct amba_device *adev, const struct amba_id *id) master->num_chipselect = platform_info->num_chipselect; master->cleanup = pl022_cleanup; master->setup = pl022_setup; - master->transfer = pl022_transfer; + master->prepare_transfer_hardware = pl022_prepare_transfer_hardware; + master->transfer_one_message = pl022_transfer_one_message; + master->unprepare_transfer_hardware = pl022_unprepare_transfer_hardware; + master->rt = platform_info->rt; /* * Supports mode 0-3, loopback, and active low CS. Transfers are @@ -2241,6 +2055,10 @@ pl022_probe(struct amba_device *adev, const struct amba_id *id) goto err_no_clk_en; } + /* Initialize transfer pump */ + tasklet_init(&pl022->pump_transfers, pump_transfers, + (unsigned long)pl022); + /* Disable SSP */ writew((readw(SSP_CR1(pl022->virtbase)) & (~SSP_CR1_MASK_SSE)), SSP_CR1(pl022->virtbase)); @@ -2260,17 +2078,6 @@ pl022_probe(struct amba_device *adev, const struct amba_id *id) platform_info->enable_dma = 0; } - /* Initialize and start queue */ - status = init_queue(pl022); - if (status != 0) { - dev_err(&adev->dev, "probe - problem initializing queue\n"); - goto err_init_queue; - } - status = start_queue(pl022); - if (status != 0) { - dev_err(&adev->dev, "probe - problem starting queue\n"); - goto err_start_queue; - } /* Register with the SPI framework */ amba_set_drvdata(adev, pl022); status = spi_register_master(master); @@ -2296,9 +2103,6 @@ pl022_probe(struct amba_device *adev, const struct amba_id *id) return 0; err_spi_register: - err_start_queue: - err_init_queue: - destroy_queue(pl022); if (platform_info->enable_dma) pl022_dma_remove(pl022); @@ -2334,9 +2138,6 @@ pl022_remove(struct amba_device *adev) */ pm_runtime_get_noresume(&adev->dev); - /* Remove the queue */ - if (destroy_queue(pl022) != 0) - dev_err(&adev->dev, "queue remove failed\n"); load_ssp_default_config(pl022); if (pl022->master_info->enable_dma) pl022_dma_remove(pl022); @@ -2358,12 +2159,12 @@ pl022_remove(struct amba_device *adev) static int pl022_suspend(struct device *dev) { struct pl022 *pl022 = dev_get_drvdata(dev); - int status = 0; + int ret; - status = stop_queue(pl022); - if (status) { - dev_warn(dev, "suspend cannot stop queue\n"); - return status; + ret = spi_master_suspend(pl022->master); + if (ret) { + dev_warn(dev, "cannot suspend master\n"); + return ret; } dev_dbg(dev, "suspended\n"); @@ -2373,16 +2174,16 @@ static int pl022_suspend(struct device *dev) static int pl022_resume(struct device *dev) { struct pl022 *pl022 = dev_get_drvdata(dev); - int status = 0; + int ret; /* Start the queue running */ - status = start_queue(pl022); - if (status) - dev_err(dev, "problem starting queue (%d)\n", status); + ret = spi_master_resume(pl022->master); + if (ret) + dev_err(dev, "problem starting queue (%d)\n", ret); else dev_dbg(dev, "resumed\n"); - return status; + return ret; } #endif /* CONFIG_PM */ diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index b2ccdea30cb9..5ae1e84d9037 100644 --- 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_info const *info, unsigned n) /*-------------------------------------------------------------------------*/ +/** + * 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 +912,17 @@ int spi_register_master(struct spi_master *master) 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) + dev_info(dev, "master is unqueued, this is deprecated\n"); + else { + 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 +938,6 @@ done: } EXPORT_SYMBOL_GPL(spi_register_master); - static int __unregister(struct device *dev, void *null) { spi_unregister_device(to_spi_device(dev)); @@ -657,6 +958,11 @@ void spi_unregister_master(struct spi_master *master) { 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 +972,37 @@ void spi_unregister_master(struct spi_master *master) } 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; diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 176fce9cc6b1..f9e30a5b3543 100644 --- 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(struct spi_driver *sdrv) * 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 spi_master *master) 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 * |