diff options
Diffstat (limited to 'drivers/spi/spi.c')
| -rw-r--r-- | drivers/spi/spi.c | 1389 |
1 files changed, 1322 insertions, 67 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 709c836607d..d4f9670b51b 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1,7 +1,8 @@ /* - * spi.c - SPI init/core code + * SPI init/core code * * Copyright (C) 2005 David Brownell + * Copyright (C) 2008 Secret Lab Technologies Ltd. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -19,15 +20,29 @@ */ #include <linux/kernel.h> +#include <linux/kmod.h> #include <linux/device.h> #include <linux/init.h> #include <linux/cache.h> +#include <linux/dma-mapping.h> +#include <linux/dmaengine.h> #include <linux/mutex.h> #include <linux/of_device.h> +#include <linux/of_irq.h> #include <linux/slab.h> #include <linux/mod_devicetable.h> #include <linux/spi/spi.h> -#include <linux/of_spi.h> +#include <linux/of_gpio.h> +#include <linux/pm_runtime.h> +#include <linux/export.h> +#include <linux/sched/rt.h> +#include <linux/delay.h> +#include <linux/kthread.h> +#include <linux/ioport.h> +#include <linux/acpi.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/spi.h> static void spidev_release(struct device *dev) { @@ -45,14 +60,21 @@ static ssize_t modalias_show(struct device *dev, struct device_attribute *a, char *buf) { const struct spi_device *spi = to_spi_device(dev); + int len; - return sprintf(buf, "%s\n", spi->modalias); + len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1); + if (len != -ENODEV) + return len; + + return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias); } +static DEVICE_ATTR_RO(modalias); -static struct device_attribute spi_dev_attrs[] = { - __ATTR_RO(modalias), - __ATTR_NULL, +static struct attribute *spi_dev_attrs[] = { + &dev_attr_modalias.attr, + NULL, }; +ATTRIBUTE_GROUPS(spi_dev); /* modalias support makes "modprobe $MODALIAS" new-style hotplug work, * and the sysfs version makes coldplug work too. @@ -86,6 +108,10 @@ static int spi_match_device(struct device *dev, struct device_driver *drv) if (of_driver_match_device(dev, drv)) return 1; + /* Then try ACPI */ + if (acpi_driver_match_device(dev, drv)) + return 1; + if (sdrv->id_table) return !!spi_match_id(sdrv->id_table, spi); @@ -95,14 +121,18 @@ static int spi_match_device(struct device *dev, struct device_driver *drv) static int spi_uevent(struct device *dev, struct kobj_uevent_env *env) { const struct spi_device *spi = to_spi_device(dev); + int rc; + + rc = acpi_device_uevent_modalias(dev, env); + if (rc != -ENODEV) + return rc; add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias); return 0; } -#ifdef CONFIG_PM - -static int spi_suspend(struct device *dev, pm_message_t message) +#ifdef CONFIG_PM_SLEEP +static int spi_legacy_suspend(struct device *dev, pm_message_t message) { int value = 0; struct spi_driver *drv = to_spi_driver(dev->driver); @@ -117,7 +147,7 @@ static int spi_suspend(struct device *dev, pm_message_t message) return value; } -static int spi_resume(struct device *dev) +static int spi_legacy_resume(struct device *dev) { int value = 0; struct spi_driver *drv = to_spi_driver(dev->driver); @@ -132,18 +162,94 @@ static int spi_resume(struct device *dev) return value; } +static int spi_pm_suspend(struct device *dev) +{ + const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; + + if (pm) + return pm_generic_suspend(dev); + else + return spi_legacy_suspend(dev, PMSG_SUSPEND); +} + +static int spi_pm_resume(struct device *dev) +{ + const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; + + if (pm) + return pm_generic_resume(dev); + else + return spi_legacy_resume(dev); +} + +static int spi_pm_freeze(struct device *dev) +{ + const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; + + if (pm) + return pm_generic_freeze(dev); + else + return spi_legacy_suspend(dev, PMSG_FREEZE); +} + +static int spi_pm_thaw(struct device *dev) +{ + const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; + + if (pm) + return pm_generic_thaw(dev); + else + return spi_legacy_resume(dev); +} + +static int spi_pm_poweroff(struct device *dev) +{ + const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; + + if (pm) + return pm_generic_poweroff(dev); + else + return spi_legacy_suspend(dev, PMSG_HIBERNATE); +} + +static int spi_pm_restore(struct device *dev) +{ + const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; + + if (pm) + return pm_generic_restore(dev); + else + return spi_legacy_resume(dev); +} #else -#define spi_suspend NULL -#define spi_resume NULL +#define spi_pm_suspend NULL +#define spi_pm_resume NULL +#define spi_pm_freeze NULL +#define spi_pm_thaw NULL +#define spi_pm_poweroff NULL +#define spi_pm_restore NULL #endif +static const struct dev_pm_ops spi_pm = { + .suspend = spi_pm_suspend, + .resume = spi_pm_resume, + .freeze = spi_pm_freeze, + .thaw = spi_pm_thaw, + .poweroff = spi_pm_poweroff, + .restore = spi_pm_restore, + SET_RUNTIME_PM_OPS( + pm_generic_runtime_suspend, + pm_generic_runtime_resume, + NULL + ) +}; + struct bus_type spi_bus_type = { .name = "spi", - .dev_attrs = spi_dev_attrs, + .dev_groups = spi_dev_groups, .match = spi_match_device, .uevent = spi_uevent, - .suspend = spi_suspend, - .resume = spi_resume, + .pm = &spi_pm, }; EXPORT_SYMBOL_GPL(spi_bus_type); @@ -151,15 +257,25 @@ EXPORT_SYMBOL_GPL(spi_bus_type); static int spi_drv_probe(struct device *dev) { const struct spi_driver *sdrv = to_spi_driver(dev->driver); + int ret; - return sdrv->probe(to_spi_device(dev)); + acpi_dev_pm_attach(dev, true); + ret = sdrv->probe(to_spi_device(dev)); + if (ret) + acpi_dev_pm_detach(dev, true); + + return ret; } static int spi_drv_remove(struct device *dev) { const struct spi_driver *sdrv = to_spi_driver(dev->driver); + int ret; + + ret = sdrv->remove(to_spi_device(dev)); + acpi_dev_pm_detach(dev, true); - return sdrv->remove(to_spi_device(dev)); + return ret; } static void spi_drv_shutdown(struct device *dev) @@ -234,7 +350,7 @@ struct spi_device *spi_alloc_device(struct spi_master *master) if (!spi_master_get(master)) return NULL; - spi = kzalloc(sizeof *spi, GFP_KERNEL); + spi = kzalloc(sizeof(*spi), GFP_KERNEL); if (!spi) { dev_err(dev, "cannot alloc spi_device\n"); spi_master_put(master); @@ -242,14 +358,39 @@ struct spi_device *spi_alloc_device(struct spi_master *master) } spi->master = master; - spi->dev.parent = dev; + spi->dev.parent = &master->dev; spi->dev.bus = &spi_bus_type; spi->dev.release = spidev_release; + spi->cs_gpio = -ENOENT; device_initialize(&spi->dev); return spi; } EXPORT_SYMBOL_GPL(spi_alloc_device); +static void spi_dev_set_name(struct spi_device *spi) +{ + struct acpi_device *adev = ACPI_COMPANION(&spi->dev); + + if (adev) { + dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev)); + return; + } + + dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev), + spi->chip_select); +} + +static int spi_dev_check(struct device *dev, void *data) +{ + struct spi_device *spi = to_spi_device(dev); + struct spi_device *new_spi = data; + + if (spi->master == new_spi->master && + spi->chip_select == new_spi->chip_select) + return -EBUSY; + return 0; +} + /** * spi_add_device - Add spi_device allocated with spi_alloc_device * @spi: spi_device to register @@ -262,22 +403,20 @@ EXPORT_SYMBOL_GPL(spi_alloc_device); int spi_add_device(struct spi_device *spi) { static DEFINE_MUTEX(spi_add_lock); - struct device *dev = spi->master->dev.parent; - struct device *d; + struct spi_master *master = spi->master; + struct device *dev = master->dev.parent; int status; /* Chipselects are numbered 0..max; validate. */ - if (spi->chip_select >= spi->master->num_chipselect) { + if (spi->chip_select >= master->num_chipselect) { dev_err(dev, "cs%d >= max %d\n", spi->chip_select, - spi->master->num_chipselect); + master->num_chipselect); return -EINVAL; } /* Set the bus ID string */ - dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev), - spi->chip_select); - + spi_dev_set_name(spi); /* We need to make sure there's no other device with this * chipselect **BEFORE** we call setup(), else we'll trash @@ -285,15 +424,16 @@ int spi_add_device(struct spi_device *spi) */ mutex_lock(&spi_add_lock); - d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev)); - if (d != NULL) { + status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check); + if (status) { dev_err(dev, "chipselect %d already in use\n", spi->chip_select); - put_device(d); - status = -EBUSY; goto done; } + if (master->cs_gpios) + spi->cs_gpio = master->cs_gpios[spi->chip_select]; + /* Drivers may modify this initial i/o setup, but will * normally rely on the device being setup. Devices * using SPI_CS_HIGH can't coexist well otherwise... @@ -404,8 +544,7 @@ static void spi_match_master_to_boardinfo(struct spi_master *master, * The board info passed can safely be __initdata ... but be careful of * any embedded pointers (platform_data, etc), they're copied as-is. */ -int __init -spi_register_board_info(struct spi_board_info const *info, unsigned n) +int spi_register_board_info(struct spi_board_info const *info, unsigned n) { struct boardinfo *bi; int i; @@ -430,6 +569,860 @@ spi_register_board_info(struct spi_board_info const *info, unsigned n) /*-------------------------------------------------------------------------*/ +static void spi_set_cs(struct spi_device *spi, bool enable) +{ + if (spi->mode & SPI_CS_HIGH) + enable = !enable; + + if (spi->cs_gpio >= 0) + gpio_set_value(spi->cs_gpio, !enable); + else if (spi->master->set_cs) + spi->master->set_cs(spi, !enable); +} + +#ifdef CONFIG_HAS_DMA +static int spi_map_buf(struct spi_master *master, struct device *dev, + struct sg_table *sgt, void *buf, size_t len, + enum dma_data_direction dir) +{ + const bool vmalloced_buf = is_vmalloc_addr(buf); + const int desc_len = vmalloced_buf ? PAGE_SIZE : master->max_dma_len; + const int sgs = DIV_ROUND_UP(len, desc_len); + struct page *vm_page; + void *sg_buf; + size_t min; + int i, ret; + + ret = sg_alloc_table(sgt, sgs, GFP_KERNEL); + if (ret != 0) + return ret; + + for (i = 0; i < sgs; i++) { + min = min_t(size_t, len, desc_len); + + if (vmalloced_buf) { + vm_page = vmalloc_to_page(buf); + if (!vm_page) { + sg_free_table(sgt); + return -ENOMEM; + } + sg_buf = page_address(vm_page) + + ((size_t)buf & ~PAGE_MASK); + } else { + sg_buf = buf; + } + + sg_set_buf(&sgt->sgl[i], sg_buf, min); + + buf += min; + len -= min; + } + + ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir); + if (ret < 0) { + sg_free_table(sgt); + return ret; + } + + sgt->nents = ret; + + return 0; +} + +static void spi_unmap_buf(struct spi_master *master, struct device *dev, + struct sg_table *sgt, enum dma_data_direction dir) +{ + if (sgt->orig_nents) { + dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir); + sg_free_table(sgt); + } +} + +static int __spi_map_msg(struct spi_master *master, struct spi_message *msg) +{ + struct device *tx_dev, *rx_dev; + struct spi_transfer *xfer; + int ret; + + if (!master->can_dma) + return 0; + + tx_dev = &master->dma_tx->dev->device; + rx_dev = &master->dma_rx->dev->device; + + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + if (!master->can_dma(master, msg->spi, xfer)) + continue; + + if (xfer->tx_buf != NULL) { + ret = spi_map_buf(master, tx_dev, &xfer->tx_sg, + (void *)xfer->tx_buf, xfer->len, + DMA_TO_DEVICE); + if (ret != 0) + return ret; + } + + if (xfer->rx_buf != NULL) { + ret = spi_map_buf(master, rx_dev, &xfer->rx_sg, + xfer->rx_buf, xfer->len, + DMA_FROM_DEVICE); + if (ret != 0) { + spi_unmap_buf(master, tx_dev, &xfer->tx_sg, + DMA_TO_DEVICE); + return ret; + } + } + } + + master->cur_msg_mapped = true; + + return 0; +} + +static int spi_unmap_msg(struct spi_master *master, struct spi_message *msg) +{ + struct spi_transfer *xfer; + struct device *tx_dev, *rx_dev; + + if (!master->cur_msg_mapped || !master->can_dma) + return 0; + + tx_dev = &master->dma_tx->dev->device; + rx_dev = &master->dma_rx->dev->device; + + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + if (!master->can_dma(master, msg->spi, xfer)) + continue; + + spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE); + spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE); + } + + return 0; +} +#else /* !CONFIG_HAS_DMA */ +static inline int __spi_map_msg(struct spi_master *master, + struct spi_message *msg) +{ + return 0; +} + +static inline int spi_unmap_msg(struct spi_master *master, + struct spi_message *msg) +{ + return 0; +} +#endif /* !CONFIG_HAS_DMA */ + +static int spi_map_msg(struct spi_master *master, struct spi_message *msg) +{ + struct spi_transfer *xfer; + void *tmp; + unsigned int max_tx, max_rx; + + if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) { + max_tx = 0; + max_rx = 0; + + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + if ((master->flags & SPI_MASTER_MUST_TX) && + !xfer->tx_buf) + max_tx = max(xfer->len, max_tx); + if ((master->flags & SPI_MASTER_MUST_RX) && + !xfer->rx_buf) + max_rx = max(xfer->len, max_rx); + } + + if (max_tx) { + tmp = krealloc(master->dummy_tx, max_tx, + GFP_KERNEL | GFP_DMA); + if (!tmp) + return -ENOMEM; + master->dummy_tx = tmp; + memset(tmp, 0, max_tx); + } + + if (max_rx) { + tmp = krealloc(master->dummy_rx, max_rx, + GFP_KERNEL | GFP_DMA); + if (!tmp) + return -ENOMEM; + master->dummy_rx = tmp; + } + + if (max_tx || max_rx) { + list_for_each_entry(xfer, &msg->transfers, + transfer_list) { + if (!xfer->tx_buf) + xfer->tx_buf = master->dummy_tx; + if (!xfer->rx_buf) + xfer->rx_buf = master->dummy_rx; + } + } + } + + return __spi_map_msg(master, msg); +} + +/* + * spi_transfer_one_message - Default implementation of transfer_one_message() + * + * This is a standard implementation of transfer_one_message() for + * drivers which impelment a transfer_one() operation. It provides + * standard handling of delays and chip select management. + */ +static int spi_transfer_one_message(struct spi_master *master, + struct spi_message *msg) +{ + struct spi_transfer *xfer; + bool keep_cs = false; + int ret = 0; + int ms = 1; + + spi_set_cs(msg->spi, true); + + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + trace_spi_transfer_start(msg, xfer); + + reinit_completion(&master->xfer_completion); + + ret = master->transfer_one(master, msg->spi, xfer); + if (ret < 0) { + dev_err(&msg->spi->dev, + "SPI transfer failed: %d\n", ret); + goto out; + } + + if (ret > 0) { + ret = 0; + ms = xfer->len * 8 * 1000 / xfer->speed_hz; + ms += ms + 100; /* some tolerance */ + + ms = wait_for_completion_timeout(&master->xfer_completion, + msecs_to_jiffies(ms)); + } + + if (ms == 0) { + dev_err(&msg->spi->dev, "SPI transfer timed out\n"); + msg->status = -ETIMEDOUT; + } + + trace_spi_transfer_stop(msg, xfer); + + if (msg->status != -EINPROGRESS) + goto out; + + if (xfer->delay_usecs) + udelay(xfer->delay_usecs); + + if (xfer->cs_change) { + if (list_is_last(&xfer->transfer_list, + &msg->transfers)) { + keep_cs = true; + } else { + spi_set_cs(msg->spi, false); + udelay(10); + spi_set_cs(msg->spi, true); + } + } + + msg->actual_length += xfer->len; + } + +out: + if (ret != 0 || !keep_cs) + spi_set_cs(msg->spi, false); + + if (msg->status == -EINPROGRESS) + msg->status = ret; + + spi_finalize_current_message(master); + + return ret; +} + +/** + * spi_finalize_current_transfer - report completion of a transfer + * + * Called by SPI drivers using the core transfer_one_message() + * implementation to notify it that the current interrupt driven + * transfer has finished and the next one may be scheduled. + */ +void spi_finalize_current_transfer(struct spi_master *master) +{ + complete(&master->xfer_completion); +} +EXPORT_SYMBOL_GPL(spi_finalize_current_transfer); + +/** + * 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); + kfree(master->dummy_rx); + master->dummy_rx = NULL; + kfree(master->dummy_tx); + master->dummy_tx = NULL; + if (master->unprepare_transfer_hardware && + master->unprepare_transfer_hardware(master)) + dev_err(&master->dev, + "failed to unprepare transfer hardware\n"); + if (master->auto_runtime_pm) { + pm_runtime_mark_last_busy(master->dev.parent); + pm_runtime_put_autosuspend(master->dev.parent); + } + trace_spi_master_idle(master); + 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_first_entry(&master->queue, 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->auto_runtime_pm) { + ret = pm_runtime_get_sync(master->dev.parent); + if (ret < 0) { + dev_err(&master->dev, "Failed to power device: %d\n", + ret); + return; + } + } + + if (!was_busy) + trace_spi_master_busy(master); + + 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"); + + if (master->auto_runtime_pm) + pm_runtime_put(master->dev.parent); + return; + } + } + + trace_spi_message_start(master->cur_msg); + + if (master->prepare_message) { + ret = master->prepare_message(master, master->cur_msg); + if (ret) { + dev_err(&master->dev, + "failed to prepare message: %d\n", ret); + master->cur_msg->status = ret; + spi_finalize_current_message(master); + return; + } + master->cur_msg_prepared = true; + } + + ret = spi_map_msg(master, master->cur_msg); + if (ret) { + master->cur_msg->status = ret; + spi_finalize_current_message(master); + 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, "%s", + 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); + next = list_first_entry_or_null(&master->queue, 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; + int ret; + + 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); + + spi_unmap_msg(master, mesg); + + if (master->cur_msg_prepared && master->unprepare_message) { + ret = master->unprepare_message(master, mesg); + if (ret) { + dev_err(&master->dev, + "failed to unprepare message: %d\n", ret); + } + } + master->cur_msg_prepared = false; + + mesg->state = NULL; + if (mesg->complete) + mesg->complete(mesg->context); + + trace_spi_message_done(mesg); +} +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); + usleep_range(10000, 11000); + 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->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->transfer = spi_queued_transfer; + if (!master->transfer_one_message) + master->transfer_one_message = spi_transfer_one_message; + + /* Initialize and start queue */ + ret = spi_init_queue(master); + if (ret) { + dev_err(&master->dev, "problem initializing queue\n"); + goto err_init_queue; + } + master->queued = true; + ret = spi_start_queue(master); + if (ret) { + dev_err(&master->dev, "problem starting queue\n"); + goto err_start_queue; + } + + return 0; + +err_start_queue: + spi_destroy_queue(master); +err_init_queue: + 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; + int rc; + u32 value; + + 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 */ + rc = of_property_read_u32(nc, "reg", &value); + if (rc) { + dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n", + nc->full_name, rc); + spi_dev_put(spi); + continue; + } + spi->chip_select = value; + + /* 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; + if (of_find_property(nc, "spi-lsb-first", NULL)) + spi->mode |= SPI_LSB_FIRST; + + /* Device DUAL/QUAD mode */ + if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) { + switch (value) { + case 1: + break; + case 2: + spi->mode |= SPI_TX_DUAL; + break; + case 4: + spi->mode |= SPI_TX_QUAD; + break; + default: + dev_warn(&master->dev, + "spi-tx-bus-width %d not supported\n", + value); + break; + } + } + + if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) { + switch (value) { + case 1: + break; + case 2: + spi->mode |= SPI_RX_DUAL; + break; + case 4: + spi->mode |= SPI_RX_QUAD; + break; + default: + dev_warn(&master->dev, + "spi-rx-bus-width %d not supported\n", + value); + break; + } + } + + /* Device speed */ + rc = of_property_read_u32(nc, "spi-max-frequency", &value); + if (rc) { + dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n", + nc->full_name, rc); + spi_dev_put(spi); + continue; + } + spi->max_speed_hz = value; + + /* 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 */ + request_module("%s%s", SPI_MODULE_PREFIX, spi->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_COMPANION_SET(&spi->dev, adev); + 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; + } + + adev->power.flags.ignore_parent = true; + strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias)); + if (spi_add_device(spi)) { + adev->power.flags.ignore_parent = false; + 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 */ + static void spi_master_release(struct device *dev) { struct spi_master *master; @@ -445,6 +1438,7 @@ static struct class spi_master_class = { }; + /** * spi_alloc_master - allocate SPI master controller * @dev: the controller, possibly using the platform_bus @@ -462,7 +1456,8 @@ static struct class spi_master_class = { * * The caller is responsible for assigning the bus number and initializing * the master's methods before calling spi_register_master(); and (after errors - * adding the device) calling spi_master_put() to prevent a memory leak. + * adding the device) calling spi_master_put() and kfree() to prevent a memory + * leak. */ struct spi_master *spi_alloc_master(struct device *dev, unsigned size) { @@ -471,11 +1466,13 @@ struct spi_master *spi_alloc_master(struct device *dev, unsigned size) if (!dev) return NULL; - master = kzalloc(size + sizeof *master, GFP_KERNEL); + master = kzalloc(size + sizeof(*master), GFP_KERNEL); if (!master) return NULL; device_initialize(&master->dev); + master->bus_num = -1; + master->num_chipselect = 1; master->dev.class = &spi_master_class; master->dev.parent = get_device(dev); spi_master_set_devdata(master, &master[1]); @@ -484,6 +1481,47 @@ struct spi_master *spi_alloc_master(struct device *dev, unsigned size) } EXPORT_SYMBOL_GPL(spi_alloc_master); +#ifdef CONFIG_OF +static int of_spi_register_master(struct spi_master *master) +{ + int nb, i, *cs; + struct device_node *np = master->dev.of_node; + + if (!np) + return 0; + + nb = of_gpio_named_count(np, "cs-gpios"); + master->num_chipselect = max_t(int, nb, master->num_chipselect); + + /* Return error only for an incorrectly formed cs-gpios property */ + if (nb == 0 || nb == -ENOENT) + return 0; + else if (nb < 0) + return nb; + + cs = devm_kzalloc(&master->dev, + sizeof(int) * master->num_chipselect, + GFP_KERNEL); + master->cs_gpios = cs; + + if (!master->cs_gpios) + return -ENOMEM; + + for (i = 0; i < master->num_chipselect; i++) + cs[i] = -ENOENT; + + for (i = 0; i < nb; i++) + cs[i] = of_get_named_gpio(np, "cs-gpios", i); + + return 0; +} +#else +static int of_spi_register_master(struct spi_master *master) +{ + return 0; +} +#endif + /** * spi_register_master - register SPI master controller * @master: initialized master, originally from spi_alloc_master() @@ -515,12 +1553,19 @@ int spi_register_master(struct spi_master *master) if (!dev) return -ENODEV; + status = of_spi_register_master(master); + if (status) + return status; + /* even if it's just one always-selected device, there must * be at least one chipselect */ if (master->num_chipselect == 0) return -EINVAL; + if ((master->bus_num < 0) && master->dev.of_node) + master->bus_num = of_alias_get_id(master->dev.of_node, "spi"); + /* convention: dynamically assigned bus IDs count down from the max */ if (master->bus_num < 0) { /* FIXME switch to an IDR based scheme, something like @@ -533,6 +1578,9 @@ int spi_register_master(struct spi_master *master) spin_lock_init(&master->bus_lock_spinlock); mutex_init(&master->bus_lock_mutex); master->bus_lock_flag = 0; + init_completion(&master->xfer_completion); + if (!master->max_dma_len) + master->max_dma_len = INT_MAX; /* register the device, then userspace will see it. * registration fails if the bus ID is in use. @@ -544,21 +1592,65 @@ 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_del(&master->dev); + goto done; + } + } + mutex_lock(&board_lock); list_add_tail(&master->list, &spi_master_list); list_for_each_entry(bi, &board_list, list) spi_match_master_to_boardinfo(master, &bi->board_info); mutex_unlock(&board_lock); - status = 0; - - /* Register devices from the device tree */ + /* Register devices from the device tree and ACPI */ of_register_spi_devices(master); + acpi_register_spi_devices(master); done: return status; } EXPORT_SYMBOL_GPL(spi_register_master); +static void devm_spi_unregister(struct device *dev, void *res) +{ + spi_unregister_master(*(struct spi_master **)res); +} + +/** + * dev_spi_register_master - register managed SPI master controller + * @dev: device managing SPI master + * @master: initialized master, originally from spi_alloc_master() + * Context: can sleep + * + * Register a SPI device as with spi_register_master() which will + * automatically be unregister + */ +int devm_spi_register_master(struct device *dev, struct spi_master *master) +{ + struct spi_master **ptr; + int ret; + + ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL); + if (!ptr) + return -ENOMEM; + + ret = spi_register_master(master); + if (!ret) { + *ptr = master; + devres_add(dev, ptr); + } else { + devres_free(ptr); + } + + return ret; +} +EXPORT_SYMBOL_GPL(devm_spi_register_master); static int __unregister(struct device *dev, void *null) { @@ -580,20 +1672,55 @@ 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); - dummy = device_for_each_child(master->dev.parent, &master->dev, - __unregister); + dummy = device_for_each_child(&master->dev, NULL, __unregister); device_unregister(&master->dev); } EXPORT_SYMBOL_GPL(spi_unregister_master); -static int __spi_master_match(struct device *dev, void *data) +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, const void *data) { struct spi_master *m; - u16 *bus_num = data; + const u16 *bus_num = data; m = container_of(dev, struct spi_master, dev); return m->bus_num == *bus_num; @@ -650,13 +1777,35 @@ EXPORT_SYMBOL_GPL(spi_busnum_to_master); */ int spi_setup(struct spi_device *spi) { - unsigned bad_bits; - int status; + unsigned bad_bits, ugly_bits; + int status = 0; + /* check mode to prevent that DUAL and QUAD set at the same time + */ + if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) || + ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) { + dev_err(&spi->dev, + "setup: can not select dual and quad at the same time\n"); + return -EINVAL; + } + /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden + */ + if ((spi->mode & SPI_3WIRE) && (spi->mode & + (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD))) + return -EINVAL; /* help drivers fail *cleanly* when they need options * that aren't supported with their current master */ bad_bits = spi->mode & ~spi->master->mode_bits; + ugly_bits = bad_bits & + (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD); + if (ugly_bits) { + dev_warn(&spi->dev, + "setup: ignoring unsupported mode bits %x\n", + ugly_bits); + spi->mode &= ~ugly_bits; + bad_bits &= ~ugly_bits; + } if (bad_bits) { dev_err(&spi->dev, "setup: unsupported mode bits %x\n", bad_bits); @@ -666,10 +1815,13 @@ int spi_setup(struct spi_device *spi) if (!spi->bits_per_word) spi->bits_per_word = 8; - status = spi->master->setup(spi); + if (!spi->max_speed_hz) + spi->max_speed_hz = spi->master->max_speed_hz; + + if (spi->master->setup) + status = spi->master->setup(spi); - dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s" - "%u bits/w, %u Hz max --> %d\n", + dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n", (int) (spi->mode & (SPI_CPOL | SPI_CPHA)), (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "", (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "", @@ -682,9 +1834,14 @@ int spi_setup(struct spi_device *spi) } EXPORT_SYMBOL_GPL(spi_setup); -static int __spi_async(struct spi_device *spi, struct spi_message *message) +static int __spi_validate(struct spi_device *spi, struct spi_message *message) { struct spi_master *master = spi->master; + struct spi_transfer *xfer; + int w_size; + + if (list_empty(&message->transfers)) + return -EINVAL; /* Half-duplex links include original MicroWire, and ones with * only one data pin like SPI_3WIRE (switches direction) or where @@ -693,7 +1850,6 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message) */ if ((master->flags & SPI_MASTER_HALF_DUPLEX) || (spi->mode & SPI_3WIRE)) { - struct spi_transfer *xfer; unsigned flags = master->flags; list_for_each_entry(xfer, &message->transfers, transfer_list) { @@ -706,8 +1862,100 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message) } } - message->spi = spi; + /** + * Set transfer bits_per_word and max speed as spi device default if + * it is not set for this transfer. + * Set transfer tx_nbits and rx_nbits as single transfer default + * (SPI_NBITS_SINGLE) if it is not set for this transfer. + */ + list_for_each_entry(xfer, &message->transfers, transfer_list) { + message->frame_length += xfer->len; + if (!xfer->bits_per_word) + xfer->bits_per_word = spi->bits_per_word; + + if (!xfer->speed_hz) + xfer->speed_hz = spi->max_speed_hz; + + if (master->max_speed_hz && + xfer->speed_hz > master->max_speed_hz) + xfer->speed_hz = master->max_speed_hz; + + if (master->bits_per_word_mask) { + /* Only 32 bits fit in the mask */ + if (xfer->bits_per_word > 32) + return -EINVAL; + if (!(master->bits_per_word_mask & + BIT(xfer->bits_per_word - 1))) + return -EINVAL; + } + + /* + * SPI transfer length should be multiple of SPI word size + * where SPI word size should be power-of-two multiple + */ + if (xfer->bits_per_word <= 8) + w_size = 1; + else if (xfer->bits_per_word <= 16) + w_size = 2; + else + w_size = 4; + + /* No partial transfers accepted */ + if (xfer->len % w_size) + return -EINVAL; + + if (xfer->speed_hz && master->min_speed_hz && + xfer->speed_hz < master->min_speed_hz) + return -EINVAL; + + if (xfer->tx_buf && !xfer->tx_nbits) + xfer->tx_nbits = SPI_NBITS_SINGLE; + if (xfer->rx_buf && !xfer->rx_nbits) + xfer->rx_nbits = SPI_NBITS_SINGLE; + /* check transfer tx/rx_nbits: + * 1. check the value matches one of single, dual and quad + * 2. check tx/rx_nbits match the mode in spi_device + */ + if (xfer->tx_buf) { + if (xfer->tx_nbits != SPI_NBITS_SINGLE && + xfer->tx_nbits != SPI_NBITS_DUAL && + xfer->tx_nbits != SPI_NBITS_QUAD) + return -EINVAL; + if ((xfer->tx_nbits == SPI_NBITS_DUAL) && + !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD))) + return -EINVAL; + if ((xfer->tx_nbits == SPI_NBITS_QUAD) && + !(spi->mode & SPI_TX_QUAD)) + return -EINVAL; + } + /* check transfer rx_nbits */ + if (xfer->rx_buf) { + if (xfer->rx_nbits != SPI_NBITS_SINGLE && + xfer->rx_nbits != SPI_NBITS_DUAL && + xfer->rx_nbits != SPI_NBITS_QUAD) + return -EINVAL; + if ((xfer->rx_nbits == SPI_NBITS_DUAL) && + !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD))) + return -EINVAL; + if ((xfer->rx_nbits == SPI_NBITS_QUAD) && + !(spi->mode & SPI_RX_QUAD)) + return -EINVAL; + } + } + message->status = -EINPROGRESS; + + return 0; +} + +static int __spi_async(struct spi_device *spi, struct spi_message *message) +{ + struct spi_master *master = spi->master; + + message->spi = spi; + + trace_spi_message_submit(message); + return master->transfer(spi, message); } @@ -746,6 +1994,10 @@ int spi_async(struct spi_device *spi, struct spi_message *message) int ret; unsigned long flags; + ret = __spi_validate(spi, message); + if (ret != 0) + return ret; + spin_lock_irqsave(&master->bus_lock_spinlock, flags); if (master->bus_lock_flag) @@ -794,6 +2046,10 @@ int spi_async_locked(struct spi_device *spi, struct spi_message *message) int ret; unsigned long flags; + ret = __spi_validate(spi, message); + if (ret != 0) + return ret; + spin_lock_irqsave(&master->bus_lock_spinlock, flags); ret = __spi_async(spi, message); @@ -882,7 +2138,7 @@ EXPORT_SYMBOL_GPL(spi_sync); * drivers may DMA directly into and out of the message buffers. * * This call should be used by drivers that require exclusive access to the - * SPI bus. It has to be preceeded by a spi_bus_lock call. The SPI bus must + * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must * be released by a spi_bus_unlock call when the exclusive access is over. * * It returns zero on success, else a negative error code. @@ -948,7 +2204,7 @@ int spi_bus_unlock(struct spi_master *master) EXPORT_SYMBOL_GPL(spi_bus_unlock); /* portable code must never pass more than 32 bytes */ -#define SPI_BUFSIZ max(32,SMP_CACHE_BYTES) +#define SPI_BUFSIZ max(32, SMP_CACHE_BYTES) static u8 *buf; @@ -972,8 +2228,8 @@ static u8 *buf; * spi_{async,sync}() calls with dma-safe buffers. */ int spi_write_then_read(struct spi_device *spi, - const u8 *txbuf, unsigned n_tx, - u8 *rxbuf, unsigned n_rx) + const void *txbuf, unsigned n_tx, + void *rxbuf, unsigned n_rx) { static DEFINE_MUTEX(lock); @@ -982,15 +2238,22 @@ int spi_write_then_read(struct spi_device *spi, struct spi_transfer x[2]; u8 *local_buf; - /* Use preallocated DMA-safe buffer. We can't avoid copying here, - * (as a pure convenience thing), but we can keep heap costs - * out of the hot path ... + /* Use preallocated DMA-safe buffer if we can. We can't avoid + * copying here, (as a pure convenience thing), but we can + * keep heap costs out of the hot path unless someone else is + * using the pre-allocated buffer or the transfer is too large. */ - if ((n_tx + n_rx) > SPI_BUFSIZ) - return -EINVAL; + if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) { + local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx), + GFP_KERNEL | GFP_DMA); + if (!local_buf) + return -ENOMEM; + } else { + local_buf = buf; + } spi_message_init(&message); - memset(x, 0, sizeof x); + memset(x, 0, sizeof(x)); if (n_tx) { x[0].len = n_tx; spi_message_add_tail(&x[0], &message); @@ -1000,14 +2263,6 @@ int spi_write_then_read(struct spi_device *spi, spi_message_add_tail(&x[1], &message); } - /* ... unless someone else is using the pre-allocated buffer */ - if (!mutex_trylock(&lock)) { - local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); - if (!local_buf) - return -ENOMEM; - } else - local_buf = buf; - memcpy(local_buf, txbuf, n_tx); x[0].tx_buf = local_buf; x[1].rx_buf = local_buf + n_tx; |