spi: spi-ep93xx: convert to the queued driver infrastructure
authorH Hartley Sweeten <hartleys@visionengravers.com>
Mon, 8 Jul 2013 16:12:37 +0000 (09:12 -0700)
committerMark Brown <broonie@linaro.org>
Wed, 17 Jul 2013 10:10:59 +0000 (11:10 +0100)
The SPI core provides infrastructure for standard message queueing. Use
that instead of handling it in the driver.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Mika Westerberg <mika.westerberg@iki.fi>
Signed-off-by: Mark Brown <broonie@linaro.org>
drivers/spi/spi-ep93xx.c

index 2e64806b40afd8f939eb0e7079c85a1f4e07da73..4c9a50ce4f6c6274ece881a440f41a1aab01e864 100644 (file)
@@ -26,7 +26,6 @@
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
-#include <linux/workqueue.h>
 #include <linux/sched.h>
 #include <linux/scatterlist.h>
 #include <linux/spi/spi.h>
 
 /**
  * struct ep93xx_spi - EP93xx SPI controller structure
- * @lock: spinlock that protects concurrent accesses to fields @running,
- *        @current_msg and @msg_queue
  * @pdev: pointer to platform device
  * @clk: clock for the controller
  * @regs_base: pointer to ioremap()'d registers
  * @sspdr_phys: physical address of the SSPDR register
  * @min_rate: minimum clock rate (in Hz) supported by the controller
  * @max_rate: maximum clock rate (in Hz) supported by the controller
- * @running: is the queue running
- * @wq: workqueue used by the driver
- * @msg_work: work that is queued for the driver
  * @wait: wait here until given transfer is completed
- * @msg_queue: queue for the messages
  * @current_msg: message that is currently processed (or %NULL if none)
  * @tx: current byte in transfer to transmit
  * @rx: current byte in transfer to receive
  * @tx_sgt: sg table for TX transfers
  * @zeropage: dummy page used as RX buffer when only TX buffer is passed in by
  *            the client
- *
- * This structure holds EP93xx SPI controller specific information. When
- * @running is %true, driver accepts transfer requests from protocol drivers.
- * @current_msg is used to hold pointer to the message that is currently
- * processed. If @current_msg is %NULL, it means that no processing is going
- * on.
- *
- * Most of the fields are only written once and they can be accessed without
- * taking the @lock. Fields that are accessed concurrently are: @current_msg,
- * @running, and @msg_queue.
  */
 struct ep93xx_spi {
-       spinlock_t                      lock;
        const struct platform_device    *pdev;
        struct clk                      *clk;
        void __iomem                    *regs_base;
        unsigned long                   sspdr_phys;
        unsigned long                   min_rate;
        unsigned long                   max_rate;
-       bool                            running;
-       struct workqueue_struct         *wq;
-       struct work_struct              msg_work;
        struct completion               wait;
-       struct list_head                msg_queue;
        struct spi_message              *current_msg;
        size_t                          tx;
        size_t                          rx;
@@ -230,7 +208,7 @@ static int ep93xx_spi_calc_divisors(const struct ep93xx_spi *espi,
        /*
         * Make sure that max value is between values supported by the
         * controller. Note that minimum value is already checked in
-        * ep93xx_spi_transfer().
+        * ep93xx_spi_transfer_one_message().
         */
        rate = clamp(rate, espi->min_rate, espi->max_rate);
 
@@ -305,54 +283,6 @@ static int ep93xx_spi_setup(struct spi_device *spi)
        return 0;
 }
 
-/**
- * ep93xx_spi_transfer() - queue message to be transferred
- * @spi: target SPI device
- * @msg: message to be transferred
- *
- * This function is called by SPI device drivers when they are going to transfer
- * a new message. It simply puts the message in the queue and schedules
- * workqueue to perform the actual transfer later on.
- *
- * Returns %0 on success and negative error in case of failure.
- */
-static int ep93xx_spi_transfer(struct spi_device *spi, struct spi_message *msg)
-{
-       struct ep93xx_spi *espi = spi_master_get_devdata(spi->master);
-       struct spi_transfer *t;
-       unsigned long flags;
-
-       if (!msg || !msg->complete)
-               return -EINVAL;
-
-       /* first validate each transfer */
-       list_for_each_entry(t, &msg->transfers, transfer_list) {
-               if (t->speed_hz && t->speed_hz < espi->min_rate)
-                               return -EINVAL;
-       }
-
-       /*
-        * Now that we own the message, let's initialize it so that it is
-        * suitable for us. We use @msg->status to signal whether there was
-        * error in transfer and @msg->state is used to hold pointer to the
-        * current transfer (or %NULL if no active current transfer).
-        */
-       msg->state = NULL;
-       msg->status = 0;
-       msg->actual_length = 0;
-
-       spin_lock_irqsave(&espi->lock, flags);
-       if (!espi->running) {
-               spin_unlock_irqrestore(&espi->lock, flags);
-               return -ESHUTDOWN;
-       }
-       list_add_tail(&msg->queue, &espi->msg_queue);
-       queue_work(espi->wq, &espi->msg_work);
-       spin_unlock_irqrestore(&espi->lock, flags);
-
-       return 0;
-}
-
 /**
  * ep93xx_spi_cleanup() - cleans up master controller specific state
  * @spi: SPI device to cleanup
@@ -801,50 +731,29 @@ static void ep93xx_spi_process_message(struct ep93xx_spi *espi,
        ep93xx_spi_disable(espi);
 }
 
-#define work_to_espi(work) (container_of((work), struct ep93xx_spi, msg_work))
-
-/**
- * ep93xx_spi_work() - EP93xx SPI workqueue worker function
- * @work: work struct
- *
- * Workqueue worker function. This function is called when there are new
- * SPI messages to be processed. Message is taken out from the queue and then
- * passed to ep93xx_spi_process_message().
- *
- * After message is transferred, protocol driver is notified by calling
- * @msg->complete(). In case of error, @msg->status is set to negative error
- * number, otherwise it contains zero (and @msg->actual_length is updated).
- */
-static void ep93xx_spi_work(struct work_struct *work)
+static int ep93xx_spi_transfer_one_message(struct spi_master *master,
+                                          struct spi_message *msg)
 {
-       struct ep93xx_spi *espi = work_to_espi(work);
-       struct spi_message *msg;
+       struct ep93xx_spi *espi = spi_master_get_devdata(master);
+       struct spi_transfer *t;
 
-       spin_lock_irq(&espi->lock);
-       if (!espi->running || espi->current_msg ||
-               list_empty(&espi->msg_queue)) {
-               spin_unlock_irq(&espi->lock);
-               return;
+       /* first validate each transfer */
+       list_for_each_entry(t, &msg->transfers, transfer_list) {
+               if (t->speed_hz < espi->min_rate)
+                       return -EINVAL;
        }
-       msg = list_first_entry(&espi->msg_queue, struct spi_message, queue);
-       list_del_init(&msg->queue);
-       espi->current_msg = msg;
-       spin_unlock_irq(&espi->lock);
 
-       ep93xx_spi_process_message(espi, msg);
+       msg->state = NULL;
+       msg->status = 0;
+       msg->actual_length = 0;
 
-       /*
-        * Update the current message and re-schedule ourselves if there are
-        * more messages in the queue.
-        */
-       spin_lock_irq(&espi->lock);
+       espi->current_msg = msg;
+       ep93xx_spi_process_message(espi, msg);
        espi->current_msg = NULL;
-       if (espi->running && !list_empty(&espi->msg_queue))
-               queue_work(espi->wq, &espi->msg_work);
-       spin_unlock_irq(&espi->lock);
 
-       /* notify the protocol driver that we are done with this message */
-       msg->complete(msg->context);
+       spi_finalize_current_message(master);
+
+       return 0;
 }
 
 static irqreturn_t ep93xx_spi_interrupt(int irq, void *dev_id)
@@ -984,7 +893,7 @@ static int ep93xx_spi_probe(struct platform_device *pdev)
                return -ENOMEM;
 
        master->setup = ep93xx_spi_setup;
-       master->transfer = ep93xx_spi_transfer;
+       master->transfer_one_message = ep93xx_spi_transfer_one_message;
        master->cleanup = ep93xx_spi_cleanup;
        master->bus_num = pdev->id;
        master->num_chipselect = info->num_chipselect;
@@ -1002,7 +911,6 @@ static int ep93xx_spi_probe(struct platform_device *pdev)
                goto fail_release_master;
        }
 
-       spin_lock_init(&espi->lock);
        init_completion(&espi->wait);
 
        /*
@@ -1031,23 +939,13 @@ static int ep93xx_spi_probe(struct platform_device *pdev)
        if (info->use_dma && ep93xx_spi_setup_dma(espi))
                dev_warn(&pdev->dev, "DMA setup failed. Falling back to PIO\n");
 
-       espi->wq = create_singlethread_workqueue("ep93xx_spid");
-       if (!espi->wq) {
-               dev_err(&pdev->dev, "unable to create workqueue\n");
-               error = -ENOMEM;
-               goto fail_free_dma;
-       }
-       INIT_WORK(&espi->msg_work, ep93xx_spi_work);
-       INIT_LIST_HEAD(&espi->msg_queue);
-       espi->running = true;
-
        /* make sure that the hardware is disabled */
        ep93xx_spi_write_u8(espi, SSPCR1, 0);
 
        error = spi_register_master(master);
        if (error) {
                dev_err(&pdev->dev, "failed to register SPI master\n");
-               goto fail_free_queue;
+               goto fail_free_dma;
        }
 
        dev_info(&pdev->dev, "EP93xx SPI Controller at 0x%08lx irq %d\n",
@@ -1055,8 +953,6 @@ static int ep93xx_spi_probe(struct platform_device *pdev)
 
        return 0;
 
-fail_free_queue:
-       destroy_workqueue(espi->wq);
 fail_free_dma:
        ep93xx_spi_release_dma(espi);
 fail_release_master:
@@ -1070,29 +966,6 @@ static int ep93xx_spi_remove(struct platform_device *pdev)
        struct spi_master *master = platform_get_drvdata(pdev);
        struct ep93xx_spi *espi = spi_master_get_devdata(master);
 
-       spin_lock_irq(&espi->lock);
-       espi->running = false;
-       spin_unlock_irq(&espi->lock);
-
-       destroy_workqueue(espi->wq);
-
-       /*
-        * Complete remaining messages with %-ESHUTDOWN status.
-        */
-       spin_lock_irq(&espi->lock);
-       while (!list_empty(&espi->msg_queue)) {
-               struct spi_message *msg;
-
-               msg = list_first_entry(&espi->msg_queue,
-                                      struct spi_message, queue);
-               list_del_init(&msg->queue);
-               msg->status = -ESHUTDOWN;
-               spin_unlock_irq(&espi->lock);
-               msg->complete(msg->context);
-               spin_lock_irq(&espi->lock);
-       }
-       spin_unlock_irq(&espi->lock);
-
        ep93xx_spi_release_dma(espi);
 
        spi_unregister_master(master);