+/**
+ * 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) {
+ spin_unlock_irqrestore(&master->queue_lock, flags);
+ return;
+ }
+ master->busy = false;
+ spin_unlock_irqrestore(&master->queue_lock, flags);
+ if (master->unprepare_transfer_hardware &&
+ master->unprepare_transfer_hardware(master))
+ dev_err(&master->dev,
+ "failed to unprepare transfer hardware\n");
+ 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 && master->prepare_transfer_hardware) {
+ 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;
+}
+
+/*-------------------------------------------------------------------------*/
+
+#if defined(CONFIG_OF)
+/**
+ * of_register_spi_devices() - Register child devices onto the SPI bus
+ * @master: Pointer to spi_master device
+ *
+ * Registers an spi_device for each child node of master node which has a 'reg'
+ * property.
+ */
+static void of_register_spi_devices(struct spi_master *master)
+{
+ struct spi_device *spi;
+ struct device_node *nc;
+ const __be32 *prop;
+ char modalias[SPI_NAME_SIZE + 4];
+ int rc;
+ int len;
+
+ if (!master->dev.of_node)
+ return;
+
+ for_each_available_child_of_node(master->dev.of_node, nc) {
+ /* Alloc an spi_device */
+ spi = spi_alloc_device(master);
+ if (!spi) {
+ dev_err(&master->dev, "spi_device alloc error for %s\n",
+ nc->full_name);
+ spi_dev_put(spi);
+ continue;
+ }
+
+ /* Select device driver */
+ if (of_modalias_node(nc, spi->modalias,
+ sizeof(spi->modalias)) < 0) {
+ dev_err(&master->dev, "cannot find modalias for %s\n",
+ nc->full_name);
+ spi_dev_put(spi);
+ continue;
+ }
+
+ /* Device address */
+ prop = of_get_property(nc, "reg", &len);
+ if (!prop || len < sizeof(*prop)) {
+ dev_err(&master->dev, "%s has no 'reg' property\n",
+ nc->full_name);
+ spi_dev_put(spi);
+ continue;
+ }
+ spi->chip_select = be32_to_cpup(prop);
+
+ /* Mode (clock phase/polarity/etc.) */
+ if (of_find_property(nc, "spi-cpha", NULL))
+ spi->mode |= SPI_CPHA;
+ if (of_find_property(nc, "spi-cpol", NULL))
+ spi->mode |= SPI_CPOL;
+ if (of_find_property(nc, "spi-cs-high", NULL))
+ spi->mode |= SPI_CS_HIGH;
+ if (of_find_property(nc, "spi-3wire", NULL))
+ spi->mode |= SPI_3WIRE;
+
+ /* Device speed */
+ prop = of_get_property(nc, "spi-max-frequency", &len);
+ if (!prop || len < sizeof(*prop)) {
+ dev_err(&master->dev, "%s has no 'spi-max-frequency' property\n",
+ nc->full_name);
+ spi_dev_put(spi);
+ continue;
+ }
+ spi->max_speed_hz = be32_to_cpup(prop);
+
+ /* IRQ */
+ spi->irq = irq_of_parse_and_map(nc, 0);
+
+ /* Store a pointer to the node in the device structure */
+ of_node_get(nc);
+ spi->dev.of_node = nc;
+
+ /* Register the new device */
+ snprintf(modalias, sizeof(modalias), "%s%s", SPI_MODULE_PREFIX,
+ spi->modalias);
+ request_module(modalias);
+ rc = spi_add_device(spi);
+ if (rc) {
+ dev_err(&master->dev, "spi_device register error %s\n",
+ nc->full_name);
+ spi_dev_put(spi);
+ }
+
+ }
+}
+#else
+static void of_register_spi_devices(struct spi_master *master) { }
+#endif
+
+#ifdef CONFIG_ACPI
+static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
+{
+ struct spi_device *spi = data;
+
+ if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
+ struct acpi_resource_spi_serialbus *sb;
+
+ sb = &ares->data.spi_serial_bus;
+ if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
+ spi->chip_select = sb->device_selection;
+ spi->max_speed_hz = sb->connection_speed;
+
+ if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
+ spi->mode |= SPI_CPHA;
+ if (sb->clock_polarity == ACPI_SPI_START_HIGH)
+ spi->mode |= SPI_CPOL;
+ if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
+ spi->mode |= SPI_CS_HIGH;
+ }
+ } else if (spi->irq < 0) {
+ struct resource r;
+
+ if (acpi_dev_resource_interrupt(ares, 0, &r))
+ spi->irq = r.start;
+ }
+
+ /* Always tell the ACPI core to skip this resource */
+ return 1;
+}
+
+static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
+ void *data, void **return_value)
+{
+ struct spi_master *master = data;
+ struct list_head resource_list;
+ struct acpi_device *adev;
+ struct spi_device *spi;
+ int ret;
+
+ if (acpi_bus_get_device(handle, &adev))
+ return AE_OK;
+ if (acpi_bus_get_status(adev) || !adev->status.present)
+ return AE_OK;
+
+ spi = spi_alloc_device(master);
+ if (!spi) {
+ dev_err(&master->dev, "failed to allocate SPI device for %s\n",
+ dev_name(&adev->dev));
+ return AE_NO_MEMORY;
+ }
+
+ ACPI_HANDLE_SET(&spi->dev, handle);
+ spi->irq = -1;
+
+ INIT_LIST_HEAD(&resource_list);
+ ret = acpi_dev_get_resources(adev, &resource_list,
+ acpi_spi_add_resource, spi);
+ acpi_dev_free_resource_list(&resource_list);
+
+ if (ret < 0 || !spi->max_speed_hz) {
+ spi_dev_put(spi);
+ return AE_OK;
+ }
+
+ strlcpy(spi->modalias, dev_name(&adev->dev), sizeof(spi->modalias));
+ if (spi_add_device(spi)) {
+ dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
+ dev_name(&adev->dev));
+ spi_dev_put(spi);
+ }
+
+ return AE_OK;
+}
+
+static void acpi_register_spi_devices(struct spi_master *master)
+{
+ acpi_status status;
+ acpi_handle handle;
+
+ handle = ACPI_HANDLE(master->dev.parent);
+ if (!handle)
+ return;
+
+ status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
+ acpi_spi_add_device, NULL,
+ master, NULL);
+ if (ACPI_FAILURE(status))
+ dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
+}
+#else
+static inline void acpi_register_spi_devices(struct spi_master *master) {}
+#endif /* CONFIG_ACPI */
+