diff options
Diffstat (limited to 'drivers/spi/spi-pl022.c')
| -rw-r--r-- | drivers/spi/spi-pl022.c | 94 |
1 files changed, 69 insertions, 25 deletions
diff --git a/drivers/spi/spi-pl022.c b/drivers/spi/spi-pl022.c index f37ad2271ad..c3e5c4df660 100644 --- a/drivers/spi/spi-pl022.c +++ b/drivers/spi/spi-pl022.c @@ -29,7 +29,7 @@ #include <linux/errno.h> #include <linux/interrupt.h> #include <linux/spi/spi.h> -#include <linux/workqueue.h> +#include <linux/kthread.h> #include <linux/delay.h> #include <linux/clk.h> #include <linux/err.h> @@ -41,6 +41,7 @@ #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. @@ -330,12 +331,13 @@ struct vendor_data { * @clk: outgoing clock "SPICLK" for the SPI bus * @master: SPI framework hookup * @master_info: controller-specific data from machine setup - * @workqueue: a workqueue on which any spi_message request is queued - * @pump_messages: work struct for scheduling work to the workqueue + * @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 - * @busy: workqueue is busy - * @running: workqueue is running + * @busy: message pump is busy + * @running: message pump is running * @pump_transfers: Tasklet used in Interrupt Transfer mode * @cur_msg: Pointer to current spi_message being processed * @cur_transfer: Pointer to current spi_transfer @@ -365,9 +367,10 @@ struct pl022 { struct clk *clk; struct spi_master *master; struct pl022_ssp_controller *master_info; - /* Driver message queue */ - struct workqueue_struct *workqueue; - struct work_struct pump_messages; + /* 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; @@ -504,12 +507,19 @@ static void giveback(struct pl022 *pl022) pl022->cur_msg = NULL; pl022->cur_transfer = NULL; pl022->cur_chip = NULL; - queue_work(pl022->workqueue, &pl022->pump_messages); + 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); + + /* disable the SPI/SSP operation */ + writew((readw(SSP_CR1(pl022->virtbase)) & + (~SSP_CR1_MASK_SSE)), SSP_CR1(pl022->virtbase)); + + /* This message is completed, so let's turn off the clocks & power */ + pm_runtime_put(&pl022->adev->dev); } /** @@ -914,6 +924,12 @@ static int configure_dma(struct pl022 *pl022) struct dma_async_tx_descriptor *rxdesc; struct dma_async_tx_descriptor *txdesc; + /* DMA burstsize should be same as the FIFO trigger level */ + rx_conf.src_maxburst = pl022->rx_lev_trig ? 1 << + (pl022->rx_lev_trig + 1) : pl022->rx_lev_trig; + tx_conf.dst_maxburst = pl022->tx_lev_trig ? 1 << + (pl022->tx_lev_trig + 1) : pl022->tx_lev_trig; + /* Check that the channels are available */ if (!rxchan || !txchan) return -ENODEV; @@ -1494,8 +1510,8 @@ out: } /** - * pump_messages - Workqueue function which processes spi message queue - * @data: pointer to private data of SSP driver + * 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 @@ -1503,7 +1519,7 @@ out: * based on the kind of the transfer * */ -static void pump_messages(struct work_struct *work) +static void pump_messages(struct kthread_work *work) { struct pl022 *pl022 = container_of(work, struct pl022, pump_messages); @@ -1556,7 +1572,7 @@ static void pump_messages(struct work_struct *work) if (!was_busy) /* * We enable the core voltage and clocks here, then the clocks - * and core will be disabled when this workqueue is run again + * 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); @@ -1572,6 +1588,8 @@ static void pump_messages(struct work_struct *work) 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); @@ -1581,11 +1599,29 @@ static int __init init_queue(struct pl022 *pl022) tasklet_init(&pl022->pump_transfers, pump_transfers, (unsigned long)pl022); - INIT_WORK(&pl022->pump_messages, pump_messages); - pl022->workqueue = create_singlethread_workqueue( + init_kthread_worker(&pl022->kworker); + pl022->kworker_task = kthread_run(kthread_worker_fn, + &pl022->kworker, dev_name(pl022->master->dev.parent)); - if (pl022->workqueue == NULL) - return -EBUSY; + 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; } @@ -1608,7 +1644,7 @@ static int start_queue(struct pl022 *pl022) pl022->next_msg_cs_active = false; spin_unlock_irqrestore(&pl022->queue_lock, flags); - queue_work(pl022->workqueue, &pl022->pump_messages); + queue_kthread_work(&pl022->kworker, &pl022->pump_messages); return 0; } @@ -1646,16 +1682,20 @@ 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 + + /* + * We are unloading the module or failing to load (only two calls * to this routine), and neither call can handle a return value. - * However, destroy_workqueue calls flush_workqueue, and that 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 destroy_workqueue, so return anyway. */ + * 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; - destroy_workqueue(pl022->workqueue); + flush_kthread_worker(&pl022->kworker); + kthread_stop(pl022->kworker_task); return 0; } @@ -1802,7 +1842,7 @@ static int pl022_transfer(struct spi_device *spi, struct spi_message *msg) list_add_tail(&msg->queue, &pl022->queue); if (pl022->running && !pl022->busy) - queue_work(pl022->workqueue, &pl022->pump_messages); + queue_kthread_work(&pl022->kworker, &pl022->pump_messages); spin_unlock_irqrestore(&pl022->queue_lock, flags); return 0; @@ -2195,6 +2235,9 @@ pl022_probe(struct amba_device *adev, const struct amba_id *id) printk(KERN_INFO "pl022: mapped registers from 0x%08x to %p\n", adev->res.start, pl022->virtbase); + pm_runtime_enable(dev); + pm_runtime_resume(dev); + pl022->clk = clk_get(&adev->dev, NULL); if (IS_ERR(pl022->clk)) { status = PTR_ERR(pl022->clk); @@ -2318,6 +2361,7 @@ pl022_remove(struct amba_device *adev) clk_disable(pl022->clk); clk_unprepare(pl022->clk); clk_put(pl022->clk); + pm_runtime_disable(&adev->dev); iounmap(pl022->virtbase); amba_release_regions(adev); tasklet_disable(&pl022->pump_transfers); |