/*
- * 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
*/
#include <linux/kernel.h>
+#include <linux/kmod.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/cache.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>
static void spidev_release(struct device *dev)
{
{
const struct spi_device *spi = to_spi_device(dev);
- return sprintf(buf, "%s\n", spi->modalias);
+ return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
}
static struct device_attribute spi_dev_attrs[] = {
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);
SET_RUNTIME_PM_OPS(
pm_generic_runtime_suspend,
pm_generic_runtime_resume,
- pm_generic_runtime_idle
+ NULL
)
};
}
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;
}
int spi_add_device(struct spi_device *spi)
{
static DEFINE_MUTEX(spi_add_lock);
- struct device *dev = spi->master->dev.parent;
+ struct spi_master *master = spi->master;
+ struct device *dev = master->dev.parent;
struct device *d;
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;
}
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...
* 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;
/*-------------------------------------------------------------------------*/
+/**
+ * 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 */
+
static void spi_master_release(struct device *dev)
{
struct spi_master *master;
};
+
/**
* spi_alloc_master - allocate SPI master controller
* @dev: the controller, possibly using the platform_bus
*
* 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)
{
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]);
}
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(nb, (int)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()
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
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)
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 int __unregister(struct device *dev, void *null)
{
spi_unregister_device(to_spi_device(dev));
{
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);
}
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;
int spi_setup(struct spi_device *spi)
{
unsigned bad_bits;
- int status;
+ int status = 0;
/* help drivers fail *cleanly* when they need options
* that aren't supported with their current master
if (!spi->bits_per_word)
spi->bits_per_word = 8;
- status = spi->master->setup(spi);
+ 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",
static int __spi_async(struct spi_device *spi, struct spi_message *message)
{
struct spi_master *master = spi->master;
+ struct spi_transfer *xfer;
/* Half-duplex links include original MicroWire, and ones with
* only one data pin like SPI_3WIRE (switches direction) or where
*/
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) {
}
}
+ /**
+ * Set transfer bits_per_word and max speed as spi device default if
+ * it is not set for this transfer.
+ */
+ list_for_each_entry(xfer, &message->transfers, transfer_list) {
+ 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->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;
+ }
+ }
+
message->spi = spi;
message->status = -EINPROGRESS;
return master->transfer(spi, message);
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);
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;
projects / firefly-linux-kernel-4.4.55.git / blobdiff