u64_stats_add(&stats->bytes, xfer->len); if (spi_valid_txbuf(msg, xfer))
u64_stats_add(&stats->bytes_tx, xfer->len); if (spi_valid_rxbuf(msg, xfer))
u64_stats_add(&stats->bytes_rx, xfer->len);
u64_stats_update_end(&stats->syncp);
put_cpu();
}
/* * modalias support makes "modprobe $MODALIAS" new-style hotplug work, * and the sysfs version makes coldplug work too.
*/ staticconststruct spi_device_id *spi_match_id(conststruct spi_device_id *id, constchar *name)
{ while (id->name[0]) { if (!strcmp(name, id->name)) return id;
id++;
} return NULL;
}
/** * __spi_register_driver - register a SPI driver * @owner: owner module of the driver to register * @sdrv: the driver to register * Context: can sleep * * Return: zero on success, else a negative error code.
*/ int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
{
sdrv->driver.owner = owner;
sdrv->driver.bus = &spi_bus_type;
/* * For Really Good Reasons we use spi: modaliases not of: * modaliases for DT so module autoloading won't work if we * don't have a spi_device_id as well as a compatible string.
*/ if (sdrv->driver.of_match_table) { conststruct of_device_id *of_id;
for (of_id = sdrv->driver.of_match_table; of_id->compatible[0];
of_id++) { constchar *of_name;
/* Strip off any vendor prefix */
of_name = strnchr(of_id->compatible, sizeof(of_id->compatible), ','); if (of_name)
of_name++; else
of_name = of_id->compatible;
if (sdrv->id_table) { conststruct spi_device_id *spi_id;
spi_id = spi_match_id(sdrv->id_table, of_name); if (spi_id) continue;
} else { if (strcmp(sdrv->driver.name, of_name) == 0) continue;
}
pr_warn("SPI driver %s has no spi_device_id for %s\n",
sdrv->driver.name, of_id->compatible);
}
}
/* * SPI devices should normally not be created by SPI device drivers; that * would make them board-specific. Similarly with SPI controller drivers. * Device registration normally goes into like arch/.../mach.../board-YYY.c * with other readonly (flashable) information about mainboard devices.
*/
/* * Used to protect add/del operation for board_info list and * spi_controller list, and their matching process also used * to protect object of type struct idr.
*/ static DEFINE_MUTEX(board_lock);
/** * spi_alloc_device - Allocate a new SPI device * @ctlr: Controller to which device is connected * Context: can sleep * * Allows a driver to allocate and initialize a spi_device without * registering it immediately. This allows a driver to directly * fill the spi_device with device parameters before calling * spi_add_device() on it. * * Caller is responsible to call spi_add_device() on the returned * spi_device structure to add it to the SPI controller. If the caller * needs to discard the spi_device without adding it, then it should * call spi_dev_put() on it. * * Return: a pointer to the new device, or NULL.
*/ struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
{ struct spi_device *spi;
/* * Zero(0) is a valid physical CS value and can be located at any * logical CS in the spi->chip_select[]. If all the physical CS * are initialized to 0 then It would be difficult to differentiate * between a valid physical CS 0 & an unused logical CS whose physical * CS can be 0. As a solution to this issue initialize all the CS to -1. * Now all the unused logical CS will have -1 physical CS value & can be * ignored while performing physical CS validity checks.
*/ #define SPI_INVALID_CS ((s8)-1)
for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) { /* Chipselects are numbered 0..max; validate. */
cs = spi_get_chipselect(spi, idx); if (is_valid_cs(cs) && cs >= ctlr->num_chipselect) {
dev_err(dev, "cs%d >= max %d\n", spi_get_chipselect(spi, idx),
ctlr->num_chipselect); return -EINVAL;
}
}
/* * Make sure that multiple logical CS doesn't map to the same physical CS. * For example, spi->chip_select[0] != spi->chip_select[1] and so on.
*/ if (!spi_controller_is_target(ctlr)) { for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
status = spi_dev_check_cs(dev, spi, idx, spi, idx + 1); if (status) return status;
}
}
/* Set the bus ID string */
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 * its configuration.
*/
status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check); if (status) return status;
/* Controller may unregister concurrently */ if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
!device_is_registered(&ctlr->dev)) { return -ENODEV;
}
if (ctlr->cs_gpiods) {
u8 cs;
for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
cs = spi_get_chipselect(spi, idx); if (is_valid_cs(cs))
spi_set_csgpiod(spi, idx, ctlr->cs_gpiods[cs]);
}
}
/* * 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...
*/
status = spi_setup(spi); if (status < 0) {
dev_err(dev, "can't setup %s, status %d\n",
dev_name(&spi->dev), status); return status;
}
/* Device may be bound to an active driver when this returns */
status = device_add(&spi->dev); if (status < 0) {
dev_err(dev, "can't add %s, status %d\n",
dev_name(&spi->dev), status);
spi_cleanup(spi);
} else {
dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
}
return status;
}
/** * spi_add_device - Add spi_device allocated with spi_alloc_device * @spi: spi_device to register * * Companion function to spi_alloc_device. Devices allocated with * spi_alloc_device can be added onto the SPI bus with this function. * * Return: 0 on success; negative errno on failure
*/ int spi_add_device(struct spi_device *spi)
{ struct spi_controller *ctlr = spi->controller; int status;
/* Set the bus ID string */
spi_dev_set_name(spi);
mutex_lock(&ctlr->add_lock);
status = __spi_add_device(spi);
mutex_unlock(&ctlr->add_lock); return status;
}
EXPORT_SYMBOL_GPL(spi_add_device);
/** * spi_new_device - instantiate one new SPI device * @ctlr: Controller to which device is connected * @chip: Describes the SPI device * Context: can sleep * * On typical mainboards, this is purely internal; and it's not needed * after board init creates the hard-wired devices. Some development * platforms may not be able to use spi_register_board_info though, and * this is exported so that for example a USB or parport based adapter * driver could add devices (which it would learn about out-of-band). * * Return: the new device, or NULL.
*/ struct spi_device *spi_new_device(struct spi_controller *ctlr, struct spi_board_info *chip)
{ struct spi_device *proxy; int status;
/* * NOTE: caller did any chip->bus_num checks necessary. * * Also, unless we change the return value convention to use * error-or-pointer (not NULL-or-pointer), troubleshootability * suggests syslogged diagnostics are best here (ugh).
*/
proxy = spi_alloc_device(ctlr); if (!proxy) return NULL;
/* Use provided chip-select for proxy device */
spi_set_all_cs_unused(proxy);
spi_set_chipselect(proxy, 0, chip->chip_select);
proxy->max_speed_hz = chip->max_speed_hz;
proxy->mode = chip->mode;
proxy->irq = chip->irq;
strscpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
proxy->dev.platform_data = (void *) chip->platform_data;
proxy->controller_data = chip->controller_data;
proxy->controller_state = NULL; /* * By default spi->chip_select[0] will hold the physical CS number, * so set bit 0 in spi->cs_index_mask.
*/
proxy->cs_index_mask = BIT(0);
if (chip->swnode) {
status = device_add_software_node(&proxy->dev, chip->swnode); if (status) {
dev_err(&ctlr->dev, "failed to add software node to '%s': %d\n",
chip->modalias, status); goto err_dev_put;
}
}
status = spi_add_device(proxy); if (status < 0) goto err_dev_put;
/** * spi_unregister_device - unregister a single SPI device * @spi: spi_device to unregister * * Start making the passed SPI device vanish. Normally this would be handled * by spi_unregister_controller().
*/ void spi_unregister_device(struct spi_device *spi)
{ struct fwnode_handle *fwnode;
dev = spi_new_device(ctlr, bi); if (!dev)
dev_err(ctlr->dev.parent, "can't create new device for %s\n",
bi->modalias);
}
/** * spi_register_board_info - register SPI devices for a given board * @info: array of chip descriptors * @n: how many descriptors are provided * Context: can sleep * * Board-specific early init code calls this (probably during arch_initcall) * with segments of the SPI device table. Any device nodes are created later, * after the relevant parent SPI controller (bus_num) is defined. We keep * this table of devices forever, so that reloading a controller driver will * not make Linux forget about these hard-wired devices. * * Other code can also call this, e.g. a particular add-on board might provide * SPI devices through its expansion connector, so code initializing that board * would naturally declare its SPI devices. * * The board info passed can safely be __initdata ... but be careful of * any embedded pointers (platform_data, etc), they're copied as-is. * * Return: zero on success, else a negative error code.
*/ int spi_register_board_info(struct spi_board_info const *info, unsigned n)
{ struct boardinfo *bi; int i;
if (!n) return 0;
bi = kcalloc(n, sizeof(*bi), GFP_KERNEL); if (!bi) return -ENOMEM;
for (i = 0; i < n; i++, bi++, info++) { struct spi_controller *ctlr;
/** * spi_res_alloc - allocate a spi resource that is life-cycle managed * during the processing of a spi_message while using * spi_transfer_one * @spi: the SPI device for which we allocate memory * @release: the release code to execute for this resource * @size: size to alloc and return * @gfp: GFP allocation flags * * Return: the pointer to the allocated data * * This may get enhanced in the future to allocate from a memory pool * of the @spi_device or @spi_controller to avoid repeated allocations.
*/ staticvoid *spi_res_alloc(struct spi_device *spi, spi_res_release_t release,
size_t size, gfp_t gfp)
{ struct spi_res *sres;
sres = kzalloc(sizeof(*sres) + size, gfp); if (!sres) return NULL;
spi_for_each_valid_cs(spi, idx) { if (spi->controller->last_cs[idx] == spi_get_chipselect(spi, idx))
last = true;
} return last;
}
staticvoid spi_toggle_csgpiod(struct spi_device *spi, u8 idx, bool enable, bool activate)
{ /* * Historically ACPI has no means of the GPIO polarity and * thus the SPISerialBus() resource defines it on the per-chip * basis. In order to avoid a chain of negations, the GPIO * polarity is considered being Active High. Even for the cases * when _DSD() is involved (in the updated versions of ACPI) * the GPIO CS polarity must be defined Active High to avoid * ambiguity. That's why we use enable, that takes SPI_CS_HIGH * into account.
*/ if (is_acpi_device_node(dev_fwnode(&spi->dev)))
gpiod_set_value_cansleep(spi_get_csgpiod(spi, idx), !enable); else /* Polarity handled by GPIO library */
gpiod_set_value_cansleep(spi_get_csgpiod(spi, idx), activate);
if (activate)
spi_delay_exec(&spi->cs_setup, NULL); else
spi_delay_exec(&spi->cs_inactive, NULL);
}
/* * Avoid calling into the driver (or doing delays) if the chip select * isn't actually changing from the last time this was called.
*/ if (!force && (enable == spi_is_last_cs(spi)) &&
(spi->controller->last_cs_index_mask == spi->cs_index_mask) &&
(spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH))) return;
ret = sg_alloc_table(sgt, sgs, GFP_KERNEL); if (ret != 0) return ret;
sg = &sgt->sgl[0]; for (i = 0; i < sgs; i++) {
if (vmalloced_buf || kmap_buf) { /* * Next scatterlist entry size is the minimum between * the desc_len and the remaining buffer length that * fits in a page.
*/
min = min_t(size_t, desc_len,
min_t(size_t, len,
PAGE_SIZE - offset_in_page(buf))); if (vmalloced_buf)
vm_page = vmalloc_to_page(buf); else
vm_page = kmap_to_page(buf); if (!vm_page) {
sg_free_table(sgt); return -ENOMEM;
}
sg_set_page(sg, vm_page,
min, offset_in_page(buf));
} else {
min = min_t(size_t, len, desc_len);
sg_buf = buf;
sg_set_buf(sg, sg_buf, min);
}
buf += min;
len -= min;
sg = sg_next(sg);
}
ret = dma_map_sgtable(dev, sgt, dir, attrs); if (ret < 0) {
sg_free_table(sgt); return ret;
}
ret = -ENOMSG;
list_for_each_entry(xfer, &msg->transfers, transfer_list) { /* The sync is done before each transfer. */ unsignedlong attrs = DMA_ATTR_SKIP_CPU_SYNC;
if (!ctlr->can_dma(ctlr, msg->spi, xfer)) continue;
if (xfer->tx_buf != NULL) {
ret = spi_map_buf_attrs(ctlr, tx_dev, &xfer->tx_sg,
(void *)xfer->tx_buf,
xfer->len, DMA_TO_DEVICE,
attrs); if (ret != 0) return ret;
xfer->tx_sg_mapped = true;
}
if (xfer->rx_buf != NULL) {
ret = spi_map_buf_attrs(ctlr, rx_dev, &xfer->rx_sg,
xfer->rx_buf, xfer->len,
DMA_FROM_DEVICE, attrs); if (ret != 0) {
spi_unmap_buf_attrs(ctlr, tx_dev,
&xfer->tx_sg, DMA_TO_DEVICE,
attrs);
return ret;
}
xfer->rx_sg_mapped = true;
}
} /* No transfer has been mapped, bail out with success */ if (ret) return 0;
list_for_each_entry(xfer, &msg->transfers, transfer_list) { /* The sync has already been done after each transfer. */ unsignedlong attrs = DMA_ATTR_SKIP_CPU_SYNC;
if (xfer->rx_sg_mapped)
spi_unmap_buf_attrs(ctlr, rx_dev, &xfer->rx_sg,
DMA_FROM_DEVICE, attrs);
xfer->rx_sg_mapped = false;
list_for_each_entry(xfer, &msg->transfers, transfer_list) { /* * Restore the original value of tx_buf or rx_buf if they are * NULL.
*/ if (xfer->tx_buf == ctlr->dummy_tx)
xfer->tx_buf = NULL; if (xfer->rx_buf == ctlr->dummy_rx)
xfer->rx_buf = NULL;
}
if (spi_controller_is_target(ctlr)) { if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n"); return -EINTR;
}
} else { if (!speed_hz)
speed_hz = 100000;
/* * For each byte we wait for 8 cycles of the SPI clock. * Since speed is defined in Hz and we want milliseconds, * use respective multiplier, but before the division, * otherwise we may get 0 for short transfers.
*/
ms = 8LL * MSEC_PER_SEC * xfer->len;
do_div(ms, speed_hz);
/* * Increase it twice and add 200 ms tolerance, use * predefined maximum in case of overflow.
*/
ms += ms + 200; if (ms > UINT_MAX)
ms = UINT_MAX;
ms = wait_for_completion_timeout(&ctlr->xfer_completion,
msecs_to_jiffies(ms));
if (ms == 0) {
SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
dev_err(&msg->spi->dev, "SPI transfer timed out\n"); return -ETIMEDOUT;
}
if (xfer->error & SPI_TRANS_FAIL_IO) return -EIO;
}
return 0;
}
staticvoid _spi_transfer_delay_ns(u32 ns)
{ if (!ns) return; if (ns <= NSEC_PER_USEC) {
ndelay(ns);
} else {
u32 us = DIV_ROUND_UP(ns, NSEC_PER_USEC);
fsleep(us);
}
}
int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
{
u32 delay = _delay->value;
u32 unit = _delay->unit;
u32 hz;
if (!delay) return 0;
switch (unit) { case SPI_DELAY_UNIT_USECS:
delay *= NSEC_PER_USEC; break; case SPI_DELAY_UNIT_NSECS: /* Nothing to do here */ break; case SPI_DELAY_UNIT_SCK: /* Clock cycles need to be obtained from spi_transfer */ if (!xfer) return -EINVAL; /* * If there is unknown effective speed, approximate it * by underestimating with half of the requested Hz.
*/
hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2; if (!hz) return -EINVAL;
/* Return early on "fast" mode - for everything but USECS */ if (!delay) { if (unit == SPI_DELAY_UNIT_USECS)
_spi_transfer_delay_ns(default_delay_ns); return;
}
ret = spi_delay_exec(&xfer->cs_change_delay, xfer); if (ret) {
dev_err_once(&msg->spi->dev, "Use of unsupported delay unit %i, using default of %luus\n",
unit, default_delay_ns / NSEC_PER_USEC);
_spi_transfer_delay_ns(default_delay_ns);
}
}
/* * spi_transfer_one_message - Default implementation of transfer_one_message() * * This is a standard implementation of transfer_one_message() for * drivers which implement a transfer_one() operation. It provides * standard handling of delays and chip select management.
*/ staticint spi_transfer_one_message(struct spi_controller *ctlr, struct spi_message *msg)
{ struct spi_transfer *xfer; bool keep_cs = false; int ret = 0; struct spi_statistics __percpu *statm = ctlr->pcpu_statistics; struct spi_statistics __percpu *stats = msg->spi->pcpu_statistics;
out: if (ret != 0 || !keep_cs)
spi_set_cs(msg->spi, false, false);
if (msg->status == -EINPROGRESS)
msg->status = ret;
if (msg->status && ctlr->handle_err)
ctlr->handle_err(ctlr, msg);
spi_finalize_current_message(ctlr);
return ret;
}
/** * spi_finalize_current_transfer - report completion of a transfer * @ctlr: the controller reporting completion * * 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_controller *ctlr)
{
complete(&ctlr->xfer_completion);
}
EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
if (!was_busy && ctlr->auto_runtime_pm) {
ret = pm_runtime_get_sync(ctlr->dev.parent); if (ret < 0) {
pm_runtime_put_noidle(ctlr->dev.parent);
dev_err(&ctlr->dev, "Failed to power device: %d\n",
ret);
if (!was_busy && ctlr->prepare_transfer_hardware) {
ret = ctlr->prepare_transfer_hardware(ctlr); if (ret) {
dev_err(&ctlr->dev, "failed to prepare transfer hardware: %d\n",
ret);
if (ctlr->auto_runtime_pm)
pm_runtime_put(ctlr->dev.parent);
/* * Drivers implementation of transfer_one_message() must arrange for * spi_finalize_current_message() to get called. Most drivers will do * this in the calling context, but some don't. For those cases, a * completion is used to guarantee that this function does not return * until spi_finalize_current_message() is done accessing * ctlr->cur_msg. * Use of the following two flags enable to opportunistically skip the * use of the completion since its use involves expensive spin locks. * In case of a race with the context that calls * spi_finalize_current_message() the completion will always be used, * due to strict ordering of these flags using barriers.
*/
WRITE_ONCE(ctlr->cur_msg_incomplete, true);
WRITE_ONCE(ctlr->cur_msg_need_completion, false);
reinit_completion(&ctlr->cur_msg_completion);
smp_wmb(); /* Make these available to spi_finalize_current_message() */
ret = ctlr->transfer_one_message(ctlr, msg); if (ret) {
dev_err(&ctlr->dev, "failed to transfer one message from queue\n"); return ret;
}
WRITE_ONCE(ctlr->cur_msg_need_completion, true);
smp_mb(); /* See spi_finalize_current_message()... */ if (READ_ONCE(ctlr->cur_msg_incomplete))
wait_for_completion(&ctlr->cur_msg_completion);
return 0;
}
/** * __spi_pump_messages - function which processes SPI message queue * @ctlr: controller to process queue for * @in_kthread: true if we are in the context of the message pump thread * * 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. * * Note that it is called both from the kthread itself and also from * inside spi_sync(); the queue extraction handling at the top of the * function should deal with this safely.
*/ staticvoid __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
{ struct spi_message *msg; bool was_busy = false; unsignedlong flags; int ret;
/* Take the I/O mutex */
mutex_lock(&ctlr->io_mutex);
/** * spi_pump_messages - kthread work function which processes spi message queue * @work: pointer to kthread work struct contained in the controller struct
*/ staticvoid spi_pump_messages(struct kthread_work *work)
{ struct spi_controller *ctlr =
container_of(work, struct spi_controller, pump_messages);
__spi_pump_messages(ctlr, true);
}
/** * spi_take_timestamp_pre - helper to collect the beginning of the TX timestamp * @ctlr: Pointer to the spi_controller structure of the driver * @xfer: Pointer to the transfer being timestamped * @progress: How many words (not bytes) have been transferred so far * @irqs_off: If true, will disable IRQs and preemption for the duration of the * transfer, for less jitter in time measurement. Only compatible * with PIO drivers. If true, must follow up with * spi_take_timestamp_post or otherwise system will crash. * WARNING: for fully predictable results, the CPU frequency must * also be under control (governor). * * This is a helper for drivers to collect the beginning of the TX timestamp * for the requested byte from the SPI transfer. The frequency with which this * function must be called (once per word, once for the whole transfer, once * per batch of words etc) is arbitrary as long as the @tx buffer offset is * greater than or equal to the requested byte at the time of the call. The * timestamp is only taken once, at the first such call. It is assumed that * the driver advances its @tx buffer pointer monotonically.
*/ void spi_take_timestamp_pre(struct spi_controller *ctlr, struct spi_transfer *xfer,
size_t progress, bool irqs_off)
{ if (!xfer->ptp_sts) return;
if (xfer->timestamped) return;
if (progress > xfer->ptp_sts_word_pre) return;
/* Capture the resolution of the timestamp */
xfer->ptp_sts_word_pre = progress;
if (irqs_off) {
local_irq_save(ctlr->irq_flags);
preempt_disable();
}
/** * spi_take_timestamp_post - helper to collect the end of the TX timestamp * @ctlr: Pointer to the spi_controller structure of the driver * @xfer: Pointer to the transfer being timestamped * @progress: How many words (not bytes) have been transferred so far * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU. * * This is a helper for drivers to collect the end of the TX timestamp for * the requested byte from the SPI transfer. Can be called with an arbitrary * frequency: only the first call where @tx exceeds or is equal to the * requested word will be timestamped.
*/ void spi_take_timestamp_post(struct spi_controller *ctlr, struct spi_transfer *xfer,
size_t progress, bool irqs_off)
{ if (!xfer->ptp_sts) return;
if (xfer->timestamped) return;
if (progress < xfer->ptp_sts_word_post) return;
ptp_read_system_postts(xfer->ptp_sts);
if (irqs_off) {
local_irq_restore(ctlr->irq_flags);
preempt_enable();
}
/* Capture the resolution of the timestamp */
xfer->ptp_sts_word_post = progress;
/** * spi_set_thread_rt - set the controller to pump at realtime priority * @ctlr: controller to boost priority of * * This can be called because the controller requested realtime priority * (by setting the ->rt value before calling spi_register_controller()) or * because a device on the bus said that its transfers needed realtime * priority. * * NOTE: at the moment if any device on a bus says it needs realtime then * the thread will be at realtime priority for all transfers on that * controller. If this eventually becomes a problem we may see if we can * find a way to boost the priority only temporarily during relevant * transfers.
*/ staticvoid spi_set_thread_rt(struct spi_controller *ctlr)
{
dev_info(&ctlr->dev, "will run message pump with realtime priority\n");
sched_set_fifo(ctlr->kworker->task);
}
/* * Controller 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 (ctlr->rt)
spi_set_thread_rt(ctlr);
return 0;
}
/** * spi_get_next_queued_message() - called by driver to check for queued * messages * @ctlr: the controller to check for queued messages * * If there are more messages in the queue, the next message is returned from * this call. * * Return: the next message in the queue, else NULL if the queue is empty.
*/ struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
{ struct spi_message *next; unsignedlong flags;
/* Get a pointer to the next message, if any */
spin_lock_irqsave(&ctlr->queue_lock, flags);
next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
queue);
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
/* * __spi_unoptimize_message - shared implementation of spi_unoptimize_message() * and spi_maybe_unoptimize_message() * @msg: the message to unoptimize * * Peripheral drivers should use spi_unoptimize_message() and callers inside * core should use spi_maybe_unoptimize_message() rather than calling this * function directly. * * It is not valid to call this on a message that is not currently optimized.
*/ staticvoid __spi_unoptimize_message(struct spi_message *msg)
{ struct spi_controller *ctlr = msg->spi->controller;
if (ctlr->unoptimize_message)
ctlr->unoptimize_message(msg);
spi_res_release(ctlr, msg);
msg->optimized = false;
msg->opt_state = NULL;
}
/* * spi_maybe_unoptimize_message - unoptimize msg not managed by a peripheral * @msg: the message to unoptimize * * This function is used to unoptimize a message if and only if it was * optimized by the core (via spi_maybe_optimize_message()).
*/ staticvoid spi_maybe_unoptimize_message(struct spi_message *msg)
{ if (!msg->pre_optimized && msg->optimized &&
!msg->spi->controller->defer_optimize_message)
__spi_unoptimize_message(msg);
}
/** * spi_finalize_current_message() - the current message is complete * @ctlr: the controller 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_controller *ctlr)
{ struct spi_transfer *xfer; struct spi_message *mesg; int ret;
if (unlikely(ctlr->ptp_sts_supported))
list_for_each_entry(xfer, &mesg->transfers, transfer_list)
WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
spi_unmap_msg(ctlr, mesg);
if (mesg->prepared && ctlr->unprepare_message) {
ret = ctlr->unprepare_message(ctlr, mesg); if (ret) {
dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
ret);
}
}
mesg->prepared = false;
spi_maybe_unoptimize_message(mesg);
WRITE_ONCE(ctlr->cur_msg_incomplete, false);
smp_mb(); /* See __spi_pump_transfer_message()... */ if (READ_ONCE(ctlr->cur_msg_need_completion))
complete(&ctlr->cur_msg_completion);
trace_spi_message_done(mesg);
mesg->state = NULL; if (mesg->complete)
mesg->complete(mesg->context);
}
EXPORT_SYMBOL_GPL(spi_finalize_current_message);
/* * This is a bit lame, but is optimized for the common execution path. * A wait_queue on the ctlr->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.
*/ do {
spin_lock_irqsave(&ctlr->queue_lock, flags); if (list_empty(&ctlr->queue) && !ctlr->busy) {
ctlr->running = false;
spin_unlock_irqrestore(&ctlr->queue_lock, flags); return 0;
}
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
usleep_range(10000, 11000);
} while (--limit);
return -EBUSY;
}
staticint spi_destroy_queue(struct spi_controller *ctlr)
{ int ret;
ret = spi_stop_queue(ctlr);
/* * kthread_flush_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(&ctlr->dev, "problem destroying queue\n"); return ret;
}
/** * 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 * * Return: zero on success, else a negative error code.
*/ staticint spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
{ return __spi_queued_transfer(spi, msg, true);
}
staticint spi_controller_initialize_queue(struct spi_controller *ctlr)
{ int ret;
ctlr->transfer = spi_queued_transfer; if (!ctlr->transfer_one_message)
ctlr->transfer_one_message = spi_transfer_one_message;
/* Initialize and start queue */
ret = spi_init_queue(ctlr); if (ret) {
dev_err(&ctlr->dev, "problem initializing queue\n"); goto err_init_queue;
}
ctlr->queued = true;
ret = spi_start_queue(ctlr); if (ret) {
dev_err(&ctlr->dev, "problem starting queue\n"); goto err_start_queue;
}
/** * spi_flush_queue - Send all pending messages in the queue from the callers' * context * @ctlr: controller to process queue for * * This should be used when one wants to ensure all pending messages have been * sent before doing something. Is used by the spi-mem code to make sure SPI * memory operations do not preempt regular SPI transfers that have been queued * before the spi-mem operation.
*/ void spi_flush_queue(struct spi_controller *ctlr)
{ if (ctlr->transfer == spi_queued_transfer)
__spi_pump_messages(ctlr, false);
}
/* Mode (clock phase/polarity/etc.) */ if (of_property_read_bool(nc, "spi-cpha"))
spi->mode |= SPI_CPHA; if (of_property_read_bool(nc, "spi-cpol"))
spi->mode |= SPI_CPOL; if (of_property_read_bool(nc, "spi-3wire"))
spi->mode |= SPI_3WIRE; if (of_property_read_bool(nc, "spi-lsb-first"))
spi->mode |= SPI_LSB_FIRST; if (of_property_read_bool(nc, "spi-cs-high"))
spi->mode |= SPI_CS_HIGH;
/* Device DUAL/QUAD mode */ if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) { switch (value) { case 0:
spi->mode |= SPI_NO_TX; break; case 1: break; case 2:
spi->mode |= SPI_TX_DUAL; break; case 4:
spi->mode |= SPI_TX_QUAD; break; case 8:
spi->mode |= SPI_TX_OCTAL; break; default:
dev_warn(&ctlr->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 0:
spi->mode |= SPI_NO_RX; break; case 1: break; case 2:
spi->mode |= SPI_RX_DUAL; break; case 4:
spi->mode |= SPI_RX_QUAD; break; case 8:
spi->mode |= SPI_RX_OCTAL; break; default:
dev_warn(&ctlr->dev, "spi-rx-bus-width %d not supported\n",
value); break;
}
}
if (spi_controller_is_target(ctlr)) { if (!of_node_name_eq(nc, "slave")) {
dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
nc); return -EINVAL;
} return 0;
}
if (ctlr->num_chipselect > SPI_CS_CNT_MAX) {
dev_err(&ctlr->dev, "No. of CS is more than max. no. of supported CS\n"); return -EINVAL;
}
spi_set_all_cs_unused(spi);
/* Device address */
rc = of_property_read_variable_u32_array(nc, "reg", &cs[0], 1,
SPI_CS_CNT_MAX); if (rc < 0) {
dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
nc, rc); return rc;
} if (rc > ctlr->num_chipselect) {
dev_err(&ctlr->dev, "%pOF has number of CS > ctlr->num_chipselect (%d)\n",
nc, rc); return -EINVAL;
} if ((of_property_present(nc, "parallel-memories")) &&
(!(ctlr->flags & SPI_CONTROLLER_MULTI_CS))) {
dev_err(&ctlr->dev, "SPI controller doesn't support multi CS\n"); return -EINVAL;
} for (idx = 0; idx < rc; idx++)
spi_set_chipselect(spi, idx, cs[idx]);
/* * By default spi->chip_select[0] will hold the physical CS number, * so set bit 0 in spi->cs_index_mask.
*/
spi->cs_index_mask = BIT(0);
/** * of_register_spi_devices() - Register child devices onto the SPI bus * @ctlr: Pointer to spi_controller device * * Registers an spi_device for each child node of controller node which * represents a valid SPI target device.
*/ staticvoid of_register_spi_devices(struct spi_controller *ctlr)
{ struct spi_device *spi; struct device_node *nc;
for_each_available_child_of_node(ctlr->dev.of_node, nc) { if (of_node_test_and_set_flag(nc, OF_POPULATED)) continue;
spi = of_register_spi_device(ctlr, nc); if (IS_ERR(spi)) {
dev_warn(&ctlr->dev, "Failed to create SPI device for %pOF\n", nc);
of_node_clear_flag(nc, OF_POPULATED);
}
}
} #else staticvoid of_register_spi_devices(struct spi_controller *ctlr) { } #endif
/** * spi_new_ancillary_device() - Register ancillary SPI device * @spi: Pointer to the main SPI device registering the ancillary device * @chip_select: Chip Select of the ancillary device * * Register an ancillary SPI device; for example some chips have a chip-select * for normal device usage and another one for setup/firmware upload. * * This may only be called from main SPI device's probe routine. * * Return: 0 on success; negative errno on failure
*/ struct spi_device *spi_new_ancillary_device(struct spi_device *spi,
u8 chip_select)
{ struct spi_controller *ctlr = spi->controller; struct spi_device *ancillary; int rc;
/* Alloc an spi_device */
ancillary = spi_alloc_device(ctlr); if (!ancillary) {
rc = -ENOMEM; goto err_out;
}
/* Use provided chip-select for ancillary device */
spi_set_all_cs_unused(ancillary);
spi_set_chipselect(ancillary, 0, chip_select);
/* Take over SPI mode/speed from SPI main device */
ancillary->max_speed_hz = spi->max_speed_hz;
ancillary->mode = spi->mode; /* * By default spi->chip_select[0] will hold the physical CS number, * so set bit 0 in spi->cs_index_mask.
*/
ancillary->cs_index_mask = BIT(0);
WARN_ON(!mutex_is_locked(&ctlr->add_lock));
/* Register the new device */
rc = __spi_add_device(ancillary); if (rc) {
dev_err(&spi->dev, "failed to register ancillary device\n"); goto err_out;
}
if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) return 1;
sb = &ares->data.spi_serial_bus; if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_SPI) return 1;
*count = *count + 1;
return 1;
}
/** * acpi_spi_count_resources - Count the number of SpiSerialBus resources * @adev: ACPI device * * Return: the number of SpiSerialBus resources in the ACPI-device's * resource-list; or a negative error code.
*/ int acpi_spi_count_resources(struct acpi_device *adev)
{
LIST_HEAD(r); int count = 0; int ret;
ret = acpi_dev_get_resources(adev, &r, acpi_spi_count, &count); if (ret < 0) return ret;
sb = &ares->data.spi_serial_bus; if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
if (lookup->index != -1 && lookup->n++ != lookup->index) return 1;
status = acpi_get_handle(NULL,
sb->resource_source.string_ptr,
&parent_handle);
if (ACPI_FAILURE(status)) return -ENODEV;
if (ctlr) { if (!device_match_acpi_handle(ctlr->dev.parent, parent_handle)) return -ENODEV;
} else { struct acpi_device *adev;
adev = acpi_fetch_acpi_dev(parent_handle); if (!adev) return -ENODEV;
ctlr = acpi_spi_find_controller_by_adev(adev); if (!ctlr) return -EPROBE_DEFER;
lookup->ctlr = ctlr;
}
/* * ACPI DeviceSelection numbering is handled by the * host controller driver in Windows and can vary * from driver to driver. In Linux we always expect * 0 .. max - 1 so we need to ask the driver to * translate between the two schemes.
*/ if (ctlr->fw_translate_cs) { int cs = ctlr->fw_translate_cs(ctlr,
sb->device_selection); if (cs < 0) return cs;
lookup->chip_select = cs;
} else {
lookup->chip_select = sb->device_selection;
}
if (acpi_dev_resource_interrupt(ares, 0, &r))
lookup->irq = r.start;
}
/* Always tell the ACPI core to skip this resource */ return 1;
}
/** * acpi_spi_device_alloc - Allocate a spi device, and fill it in with ACPI information * @ctlr: controller to which the spi device belongs * @adev: ACPI Device for the spi device * @index: Index of the spi resource inside the ACPI Node * * This should be used to allocate a new SPI device from and ACPI Device node. * The caller is responsible for calling spi_add_device to register the SPI device. * * If ctlr is set to NULL, the Controller for the SPI device will be looked up * using the resource. * If index is set to -1, index is not used. * Note: If index is -1, ctlr must be set. * * Return: a pointer to the new device, or ERR_PTR on error.
*/ struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr, struct acpi_device *adev, int index)
{
acpi_handle parent_handle = NULL; struct list_head resource_list; struct acpi_spi_lookup lookup = {}; struct spi_device *spi; int ret;
if (!ctlr && index == -1) return ERR_PTR(-EINVAL);
INIT_LIST_HEAD(&resource_list);
ret = acpi_dev_get_resources(adev, &resource_list,
acpi_spi_add_resource, &lookup);
acpi_dev_free_resource_list(&resource_list);
if (ret < 0) /* Found SPI in _CRS but it points to another controller */ return ERR_PTR(ret);
if (!lookup.max_speed_hz &&
ACPI_SUCCESS(acpi_get_parent(adev->handle, &parent_handle)) &&
device_match_acpi_handle(lookup.ctlr->dev.parent, parent_handle)) { /* Apple does not use _CRS but nested devices for SPI target devices */
acpi_spi_parse_apple_properties(adev, &lookup);
}
if (!lookup.max_speed_hz) return ERR_PTR(-ENODEV);
spi = spi_alloc_device(lookup.ctlr); if (!spi) {
dev_err(&lookup.ctlr->dev, "failed to allocate SPI device for %s\n",
dev_name(&adev->dev)); return ERR_PTR(-ENOMEM);
}
ACPI_COMPANION_SET(&spi->dev, adev);
spi->max_speed_hz = lookup.max_speed_hz;
spi->mode |= lookup.mode;
spi->irq = lookup.irq;
spi->bits_per_word = lookup.bits_per_word; /* * By default spi->chip_select[0] will hold the physical CS number, * so set bit 0 in spi->cs_index_mask.
*/
spi->cs_index_mask = BIT(0);
/* * This gets re-tried in spi_probe() for -EPROBE_DEFER handling in case * the GPIO controller does not have a driver yet. This needs to be done * here too, because this call sets the GPIO direction and/or bias. * Setting these needs to be done even if there is no driver, in which * case spi_probe() will never get called.
*/ if (spi->irq < 0)
spi->irq = acpi_dev_gpio_irq_get(adev, 0);
acpi_device_set_enumerated(adev);
adev->power.flags.ignore_parent = true; if (spi_add_device(spi)) {
adev->power.flags.ignore_parent = false;
dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
dev_name(&adev->dev));
spi_dev_put(spi);
}
#ifdef CONFIG_SPI_SLAVE /** * spi_target_abort - abort the ongoing transfer request on an SPI target controller * @spi: device used for the current transfer
*/ int spi_target_abort(struct spi_device *spi)
{ struct spi_controller *ctlr = spi->controller;
if (spi_controller_is_target(ctlr) && ctlr->target_abort) return ctlr->target_abort(ctlr);
/** * __spi_alloc_controller - allocate an SPI host or target controller * @dev: the controller, possibly using the platform_bus * @size: how much zeroed driver-private data to allocate; the pointer to this * memory is in the driver_data field of the returned device, accessible * with spi_controller_get_devdata(); the memory is cacheline aligned; * drivers granting DMA access to portions of their private data need to * round up @size using ALIGN(size, dma_get_cache_alignment()). * @target: flag indicating whether to allocate an SPI host (false) or SPI target (true) * controller * Context: can sleep * * This call is used only by SPI controller drivers, which are the * only ones directly touching chip registers. It's how they allocate * an spi_controller structure, prior to calling spi_register_controller(). * * This must be called from context that can sleep. * * The caller is responsible for assigning the bus number and initializing the * controller's methods before calling spi_register_controller(); and (after * errors adding the device) calling spi_controller_put() to prevent a memory * leak. * * Return: the SPI controller structure on success, else NULL.
*/ struct spi_controller *__spi_alloc_controller(struct device *dev, unsignedint size, bool target)
{ struct spi_controller *ctlr;
size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
if (!dev) return NULL;
ctlr = kzalloc(size + ctlr_size, GFP_KERNEL); if (!ctlr) return NULL;
/** * __devm_spi_alloc_controller - resource-managed __spi_alloc_controller() * @dev: physical device of SPI controller * @size: how much zeroed driver-private data to allocate * @target: whether to allocate an SPI host (false) or SPI target (true) controller * Context: can sleep * * Allocate an SPI controller and automatically release a reference on it * when @dev is unbound from its driver. Drivers are thus relieved from * having to call spi_controller_put(). * * The arguments to this function are identical to __spi_alloc_controller(). * * Return: the SPI controller structure on success, else NULL.
*/ struct spi_controller *__devm_spi_alloc_controller(struct device *dev, unsignedint size, bool target)
{ struct spi_controller **ptr, *ctlr;
ptr = devres_alloc(devm_spi_release_controller, sizeof(*ptr),
GFP_KERNEL); if (!ptr) return NULL;
for (i = 0; i < nb; i++) { /* * Most chipselects are active low, the inverted * semantics are handled by special quirks in gpiolib, * so initializing them GPIOD_OUT_LOW here means * "unasserted", in most cases this will drive the physical * line high.
*/
cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
GPIOD_OUT_LOW); if (IS_ERR(cs[i])) return PTR_ERR(cs[i]);
if (cs[i]) { /* * If we find a CS GPIO, name it after the device and * chip select line.
*/ char *gpioname;
staticint spi_controller_check_ops(struct spi_controller *ctlr)
{ /* * The controller may implement only the high-level SPI-memory like * operations if it does not support regular SPI transfers, and this is * valid use case. * If ->mem_ops or ->mem_ops->exec_op is NULL, we request that at least * one of the ->transfer_xxx() method be implemented.
*/ if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) { if (!ctlr->transfer && !ctlr->transfer_one &&
!ctlr->transfer_one_message) { return -EINVAL;
}
}
return 0;
}
/* Allocate dynamic bus number using Linux idr */ staticint spi_controller_id_alloc(struct spi_controller *ctlr, int start, int end)
{ int id;
mutex_lock(&board_lock);
id = idr_alloc(&spi_controller_idr, ctlr, start, end, GFP_KERNEL);
mutex_unlock(&board_lock); if (WARN(id < 0, "couldn't get idr")) return id == -ENOSPC ? -EBUSY : id;
ctlr->bus_num = id; return 0;
}
/** * spi_register_controller - register SPI host or target controller * @ctlr: initialized controller, originally from spi_alloc_host() or * spi_alloc_target() * Context: can sleep * * SPI controllers connect to their drivers using some non-SPI bus, * such as the platform bus. The final stage of probe() in that code * includes calling spi_register_controller() to hook up to this SPI bus glue. * * SPI controllers use board specific (often SOC specific) bus numbers, * and board-specific addressing for SPI devices combines those numbers * with chip select numbers. Since SPI does not directly support dynamic * device identification, boards need configuration tables telling which * chip is at which address. * * This must be called from context that can sleep. It returns zero on * success, else a negative error code (dropping the controller's refcount). * After a successful return, the caller is responsible for calling * spi_unregister_controller(). * * Return: zero on success, else a negative error code.
*/ int spi_register_controller(struct spi_controller *ctlr)
{ struct device *dev = ctlr->dev.parent; struct boardinfo *bi; int first_dynamic; int status; int idx;
if (!dev) return -ENODEV;
/* * Make sure all necessary hooks are implemented before registering * the SPI controller.
*/
status = spi_controller_check_ops(ctlr); if (status) return status;
if (ctlr->bus_num < 0)
ctlr->bus_num = of_alias_get_id(ctlr->dev.of_node, "spi"); if (ctlr->bus_num >= 0) { /* Devices with a fixed bus num must check-in with the num */
status = spi_controller_id_alloc(ctlr, ctlr->bus_num, ctlr->bus_num + 1); if (status) return status;
} if (ctlr->bus_num < 0) {
first_dynamic = of_alias_get_highest_id("spi"); if (first_dynamic < 0)
first_dynamic = 0; else
first_dynamic++;
status = spi_controller_id_alloc(ctlr, first_dynamic, 0); if (status) return status;
}
ctlr->bus_lock_flag = 0;
init_completion(&ctlr->xfer_completion);
init_completion(&ctlr->cur_msg_completion); if (!ctlr->max_dma_len)
ctlr->max_dma_len = INT_MAX;
/* * Register the device, then userspace will see it. * Registration fails if the bus ID is in use.
*/
dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
if (!spi_controller_is_target(ctlr) && ctlr->use_gpio_descriptors) {
status = spi_get_gpio_descs(ctlr); if (status) goto free_bus_id; /* * A controller using GPIO descriptors always * supports SPI_CS_HIGH if need be.
*/
ctlr->mode_bits |= SPI_CS_HIGH;
}
/* * Even if it's just one always-selected device, there must * be at least one chipselect.
*/ if (!ctlr->num_chipselect) {
status = -EINVAL; goto free_bus_id;
}
/* Setting last_cs to SPI_INVALID_CS means no chip selected */ for (idx = 0; idx < SPI_CS_CNT_MAX; idx++)
ctlr->last_cs[idx] = SPI_INVALID_CS;
status = device_add(&ctlr->dev); if (status < 0) goto free_bus_id;
dev_dbg(dev, "registered %s %s\n",
spi_controller_is_target(ctlr) ? "target" : "host",
dev_name(&ctlr->dev));
/* * If we're using a queued driver, start the queue. Note that we don't * need the queueing logic if the driver is only supporting high-level * memory operations.
*/ if (ctlr->transfer) {
dev_info(dev, "controller is unqueued, this is deprecated\n");
} elseif (ctlr->transfer_one || ctlr->transfer_one_message) {
status = spi_controller_initialize_queue(ctlr); if (status) {
device_del(&ctlr->dev); goto free_bus_id;
}
} /* Add statistics */
ctlr->pcpu_statistics = spi_alloc_pcpu_stats(dev); if (!ctlr->pcpu_statistics) {
dev_err(dev, "Error allocating per-cpu statistics\n");
status = -ENOMEM; goto destroy_queue;
}
/** * devm_spi_register_controller - register managed SPI host or target controller * @dev: device managing SPI controller * @ctlr: initialized controller, originally from spi_alloc_host() or * spi_alloc_target() * Context: can sleep * * Register a SPI device as with spi_register_controller() which will * automatically be unregistered and freed. * * Return: zero on success, else a negative error code.
*/ int devm_spi_register_controller(struct device *dev, struct spi_controller *ctlr)
{ struct spi_controller **ptr; int ret;
ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL); if (!ptr) return -ENOMEM;
ret = spi_register_controller(ctlr); if (!ret) {
*ptr = ctlr;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
/** * spi_unregister_controller - unregister SPI host or target controller * @ctlr: the controller being unregistered * Context: can sleep * * This call is used only by SPI controller drivers, which are the * only ones directly touching chip registers. * * This must be called from context that can sleep. * * Note that this function also drops a reference to the controller.
*/ void spi_unregister_controller(struct spi_controller *ctlr)
{ struct spi_controller *found; int id = ctlr->bus_num;
/* Prevent addition of new devices, unregister existing ones */ if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
mutex_lock(&ctlr->add_lock);
/* First make sure that this controller was ever added */
mutex_lock(&board_lock);
found = idr_find(&spi_controller_idr, id);
mutex_unlock(&board_lock); if (ctlr->queued) { if (spi_destroy_queue(ctlr))
dev_err(&ctlr->dev, "queue remove failed\n");
}
mutex_lock(&board_lock);
list_del(&ctlr->list);
mutex_unlock(&board_lock);
device_del(&ctlr->dev);
/* Free bus id */
mutex_lock(&board_lock); if (found == ctlr)
idr_remove(&spi_controller_idr, id);
mutex_unlock(&board_lock);
if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
mutex_unlock(&ctlr->add_lock);
/* * Release the last reference on the controller if its driver * has not yet been converted to devm_spi_alloc_host/target().
*/ if (!ctlr->devm_allocated)
put_device(&ctlr->dev);
}
EXPORT_SYMBOL_GPL(spi_unregister_controller);
int spi_controller_suspend(struct spi_controller *ctlr)
{ int ret = 0;
/* Basically no-ops for non-queued controllers */ if (ctlr->queued) {
ret = spi_stop_queue(ctlr); if (ret)
dev_err(&ctlr->dev, "queue stop failed\n");
}
/* Call extra callback if requested */ if (rxfer->release)
rxfer->release(ctlr, msg, res);
/* Insert replaced transfers back into the message */
list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
/* Remove the formerly inserted entries */ for (i = 0; i < rxfer->inserted; i++)
list_del(&rxfer->inserted_transfers[i].transfer_list);
}
/** * spi_replace_transfers - replace transfers with several transfers * and register change with spi_message.resources * @msg: the spi_message we work upon * @xfer_first: the first spi_transfer we want to replace * @remove: number of transfers to remove * @insert: the number of transfers we want to insert instead * @release: extra release code necessary in some circumstances * @extradatasize: extra data to allocate (with alignment guarantees * of struct @spi_transfer) * @gfp: gfp flags * * Returns: pointer to @spi_replaced_transfers, * PTR_ERR(...) in case of errors.
*/ staticstruct spi_replaced_transfers *spi_replace_transfers( struct spi_message *msg, struct spi_transfer *xfer_first,
size_t remove,
size_t insert,
spi_replaced_release_t release,
size_t extradatasize,
gfp_t gfp)
{ struct spi_replaced_transfers *rxfer; struct spi_transfer *xfer;
size_t i;
/* Allocate the structure using spi_res */
rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
struct_size(rxfer, inserted_transfers, insert)
+ extradatasize,
gfp); if (!rxfer) return ERR_PTR(-ENOMEM);
/* The release code to invoke before running the generic release */
rxfer->release = release;
/* Assign extradata */ if (extradatasize)
rxfer->extradata =
&rxfer->inserted_transfers[insert];
/* Init the replaced_transfers list */
INIT_LIST_HEAD(&rxfer->replaced_transfers);
/* * Assign the list_entry after which we should reinsert * the @replaced_transfers - it may be spi_message.messages!
*/
rxfer->replaced_after = xfer_first->transfer_list.prev;
/* Remove the requested number of transfers */ for (i = 0; i < remove; i++) { /* * If the entry after replaced_after it is msg->transfers * then we have been requested to remove more transfers * than are in the list.
*/ if (rxfer->replaced_after->next == &msg->transfers) {
dev_err(&msg->spi->dev, "requested to remove more spi_transfers than are available\n"); /* Insert replaced transfers back into the message */
list_splice(&rxfer->replaced_transfers,
rxfer->replaced_after);
/* Free the spi_replace_transfer structure... */
spi_res_free(rxfer);
/* ...and return with an error */ return ERR_PTR(-EINVAL);
}
/* * Remove the entry after replaced_after from list of * transfers and add it to list of replaced_transfers.
*/
list_move_tail(rxfer->replaced_after->next,
&rxfer->replaced_transfers);
}
/* * Create copy of the given xfer with identical settings * based on the first transfer to get removed.
*/ for (i = 0; i < insert; i++) { /* We need to run in reverse order */
xfer = &rxfer->inserted_transfers[insert - 1 - i];
/* Copy all spi_transfer data */
memcpy(xfer, xfer_first, sizeof(*xfer));
/* Add to list */
list_add(&xfer->transfer_list, rxfer->replaced_after);
/* Clear cs_change and delay for all but the last */ if (i) {
xfer->cs_change = false;
xfer->delay.value = 0;
}
}
/* Set up inserted... */
rxfer->inserted = insert;
/* ...and register it with spi_res/spi_message */
spi_res_add(msg, rxfer);
/* * Now handle each of those newly inserted spi_transfers. * Note that the replacements spi_transfers all are preset * to the same values as *xferp, so tx_buf, rx_buf and len * are all identical (as well as most others) * so we just have to fix up len and the pointers.
*/
/* * The first transfer just needs the length modified, so we * run it outside the loop.
*/
xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
/* All the others need rx_buf/tx_buf also set */ for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) { /* Update rx_buf, tx_buf and DMA */ if (xfers[i].rx_buf)
xfers[i].rx_buf += offset; if (xfers[i].tx_buf)
xfers[i].tx_buf += offset;
/** * spi_split_transfers_maxsize - split spi transfers into multiple transfers * when an individual transfer exceeds a * certain size * @ctlr: the @spi_controller for this transfer * @msg: the @spi_message to transform * @maxsize: the maximum when to apply this * * This function allocates resources that are automatically freed during the * spi message unoptimize phase so this function should only be called from * optimize_message callbacks. * * Return: status of transformation
*/ int spi_split_transfers_maxsize(struct spi_controller *ctlr, struct spi_message *msg,
size_t maxsize)
{ struct spi_transfer *xfer; int ret;
/* * Iterate over the transfer_list, * but note that xfer is advanced to the last transfer inserted * to avoid checking sizes again unnecessarily (also xfer does * potentially belong to a different list by the time the * replacement has happened).
*/
list_for_each_entry(xfer, &msg->transfers, transfer_list) { if (xfer->len > maxsize) {
ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
maxsize); if (ret) return ret;
}
}
/** * spi_split_transfers_maxwords - split SPI transfers into multiple transfers * when an individual transfer exceeds a * certain number of SPI words * @ctlr: the @spi_controller for this transfer * @msg: the @spi_message to transform * @maxwords: the number of words to limit each transfer to * * This function allocates resources that are automatically freed during the * spi message unoptimize phase so this function should only be called from * optimize_message callbacks. * * Return: status of transformation
*/ int spi_split_transfers_maxwords(struct spi_controller *ctlr, struct spi_message *msg,
size_t maxwords)
{ struct spi_transfer *xfer;
/* * Iterate over the transfer_list, * but note that xfer is advanced to the last transfer inserted * to avoid checking sizes again unnecessarily (also xfer does * potentially belong to a different list by the time the * replacement has happened).
*/
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
size_t maxsize; int ret;
maxsize = maxwords * spi_bpw_to_bytes(xfer->bits_per_word); if (xfer->len > maxsize) {
ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
maxsize); if (ret) return ret;
}
}
/* * Core methods for SPI controller protocol drivers. Some of the * other core methods are currently defined as inline functions.
*/
staticint __spi_validate_bits_per_word(struct spi_controller *ctlr,
u8 bits_per_word)
{ if (ctlr->bits_per_word_mask) { /* Only 32 bits fit in the mask */ if (bits_per_word > 32) return -EINVAL; if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word))) return -EINVAL;
}
return 0;
}
/** * spi_set_cs_timing - configure CS setup, hold, and inactive delays * @spi: the device that requires specific CS timing configuration * * Return: zero on success, else a negative error code.
*/ staticint spi_set_cs_timing(struct spi_device *spi)
{ struct device *parent = spi->controller->dev.parent; int status = 0;
if (spi->controller->set_cs_timing && !spi_get_csgpiod(spi, 0)) { if (spi->controller->auto_runtime_pm) {
status = pm_runtime_get_sync(parent); if (status < 0) {
pm_runtime_put_noidle(parent);
dev_err(&spi->controller->dev, "Failed to power device: %d\n",
status); return status;
}
status = spi->controller->set_cs_timing(spi);
pm_runtime_put_autosuspend(parent);
} else {
status = spi->controller->set_cs_timing(spi);
}
} return status;
}
/** * spi_setup - setup SPI mode and clock rate * @spi: the device whose settings are being modified * Context: can sleep, and no requests are queued to the device * * SPI protocol drivers may need to update the transfer mode if the * device doesn't work with its default. They may likewise need * to update clock rates or word sizes from initial values. This function * changes those settings, and must be called from a context that can sleep. * Except for SPI_CS_HIGH, which takes effect immediately, the changes take * effect the next time the device is selected and data is transferred to * or from it. When this function returns, the SPI device is deselected. * * Note that this call will fail if the protocol driver specifies an option * that the underlying controller or its driver does not support. For * example, not all hardware supports wire transfers using nine bit words, * LSB-first wire encoding, or active-high chipselects. * * Return: zero on success, else a negative error code.
*/ int spi_setup(struct spi_device *spi)
{ unsigned bad_bits, ugly_bits; int status;
/* * Check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO * are set at the same time.
*/ if ((hweight_long(spi->mode &
(SPI_TX_DUAL | SPI_TX_QUAD | SPI_NO_TX)) > 1) ||
(hweight_long(spi->mode &
(SPI_RX_DUAL | SPI_RX_QUAD | SPI_NO_RX)) > 1)) {
dev_err(&spi->dev, "setup: can not select any two of dual, quad and no-rx/tx 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_TX_OCTAL |
SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL))) return -EINVAL; /* Check against conflicting MOSI idle configuration */ if ((spi->mode & SPI_MOSI_IDLE_LOW) && (spi->mode & SPI_MOSI_IDLE_HIGH)) {
dev_err(&spi->dev, "setup: MOSI configured to idle low and high at the same time.\n"); return -EINVAL;
} /* * Help drivers fail *cleanly* when they need options * that aren't supported with their current controller. * SPI_CS_WORD has a fallback software implementation, * so it is ignored here.
*/
bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD |
SPI_NO_TX | SPI_NO_RX);
ugly_bits = bad_bits &
(SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL); 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); return -EINVAL;
}
if (!spi->bits_per_word) {
spi->bits_per_word = 8;
} else { /* * Some controllers may not support the default 8 bits-per-word * so only perform the check when this is explicitly provided.
*/
status = __spi_validate_bits_per_word(spi->controller,
spi->bits_per_word); if (status) return status;
}
if (spi->controller->setup) {
status = spi->controller->setup(spi); if (status) {
mutex_unlock(&spi->controller->io_mutex);
dev_err(&spi->controller->dev, "Failed to setup device: %d\n",
status); return status;
}
}
status = spi_set_cs_timing(spi); if (status) {
mutex_unlock(&spi->controller->io_mutex); return status;
}
if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
status = pm_runtime_resume_and_get(spi->controller->dev.parent); if (status < 0) {
mutex_unlock(&spi->controller->io_mutex);
dev_err(&spi->controller->dev, "Failed to power device: %d\n",
status); return status;
}
/* * We do not want to return positive value from pm_runtime_get, * there are many instances of devices calling spi_setup() and * checking for a non-zero return value instead of a negative * return value.
*/
status = 0;
if (list_empty(&message->transfers)) return -EINVAL;
message->spi = spi;
/* * Half-duplex links include original MicroWire, and ones with * only one data pin like SPI_3WIRE (switches direction) or where * either MOSI or MISO is missing. They can also be caused by * software limitations.
*/ if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
(spi->mode & SPI_3WIRE)) { unsigned flags = ctlr->flags;
list_for_each_entry(xfer, &message->transfers, transfer_list) { if (xfer->rx_buf && xfer->tx_buf) return -EINVAL; if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf) return -EINVAL; if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf) return -EINVAL;
}
}
/* * 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. * Ensure transfer word_delay is at least as long as that required by * device itself.
*/
message->frame_length = 0;
list_for_each_entry(xfer, &message->transfers, transfer_list) {
xfer->effective_speed_hz = 0;
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 (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
xfer->speed_hz = ctlr->max_speed_hz;
if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word)) return -EINVAL;
/* DDR mode is supported only if controller has dtr_caps=true. * default considered as SDR mode for SPI and QSPI controller. * Note: This is applicable only to QSPI controller.
*/ if (xfer->dtr_mode && !ctlr->dtr_caps) 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; elseif (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 && ctlr->min_speed_hz &&
xfer->speed_hz < ctlr->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 (spi->mode & SPI_NO_TX) return -EINVAL; if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
xfer->tx_nbits != SPI_NBITS_DUAL &&
xfer->tx_nbits != SPI_NBITS_QUAD &&
xfer->tx_nbits != SPI_NBITS_OCTAL) return -EINVAL; if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
!(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL))) return -EINVAL; if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
!(spi->mode & (SPI_TX_QUAD | SPI_TX_OCTAL))) return -EINVAL; if ((xfer->tx_nbits == SPI_NBITS_OCTAL) &&
!(spi->mode & SPI_TX_OCTAL)) return -EINVAL;
} /* Check transfer rx_nbits */ if (xfer->rx_buf) { if (spi->mode & SPI_NO_RX) return -EINVAL; if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
xfer->rx_nbits != SPI_NBITS_DUAL &&
xfer->rx_nbits != SPI_NBITS_QUAD &&
xfer->rx_nbits != SPI_NBITS_OCTAL) return -EINVAL; if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
!(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL))) return -EINVAL; if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
!(spi->mode & (SPI_RX_QUAD | SPI_RX_OCTAL))) return -EINVAL; if ((xfer->rx_nbits == SPI_NBITS_OCTAL) &&
!(spi->mode & SPI_RX_OCTAL)) return -EINVAL;
}
if (_spi_xfer_word_delay_update(xfer, spi)) return -EINVAL;
/* Make sure controller supports required offload features. */ if (xfer->offload_flags) { if (!message->offload) return -EINVAL;
if (xfer->offload_flags & ~message->offload->xfer_flags) return -EINVAL;
}
}
message->status = -EINPROGRESS;
return 0;
}
/* * spi_split_transfers - generic handling of transfer splitting * @msg: the message to split * * Under certain conditions, a SPI controller may not support arbitrary * transfer sizes or other features required by a peripheral. This function * will split the transfers in the message into smaller transfers that are * supported by the controller. * * Controllers with special requirements not covered here can also split * transfers in the optimize_message() callback. * * Context: can sleep * Return: zero on success, else a negative error code
*/ staticint spi_split_transfers(struct spi_message *msg)
{ struct spi_controller *ctlr = msg->spi->controller; struct spi_transfer *xfer; int ret;
/* * If an SPI controller does not support toggling the CS line on each * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO * for the CS line, we can emulate the CS-per-word hardware function by * splitting transfers into one-word transfers and ensuring that * cs_change is set for each transfer.
*/ if ((msg->spi->mode & SPI_CS_WORD) &&
(!(ctlr->mode_bits & SPI_CS_WORD) || spi_is_csgpiod(msg->spi))) {
ret = spi_split_transfers_maxwords(ctlr, msg, 1); if (ret) return ret;
list_for_each_entry(xfer, &msg->transfers, transfer_list) { /* Don't change cs_change on the last entry in the list */ if (list_is_last(&xfer->transfer_list, &msg->transfers)) break;
xfer->cs_change = 1;
}
} else {
ret = spi_split_transfers_maxsize(ctlr, msg,
spi_max_transfer_size(msg->spi)); if (ret) return ret;
}
return 0;
}
/* * __spi_optimize_message - shared implementation for spi_optimize_message() * and spi_maybe_optimize_message() * @spi: the device that will be used for the message * @msg: the message to optimize * * Peripheral drivers will call spi_optimize_message() and the spi core will * call spi_maybe_optimize_message() instead of calling this directly. * * It is not valid to call this on a message that has already been optimized. * * Return: zero on success, else a negative error code
*/ staticint __spi_optimize_message(struct spi_device *spi, struct spi_message *msg)
{ struct spi_controller *ctlr = spi->controller; int ret;
ret = __spi_validate(spi, msg); if (ret) return ret;
ret = spi_split_transfers(msg); if (ret) return ret;
if (ctlr->optimize_message) {
ret = ctlr->optimize_message(msg); if (ret) {
spi_res_release(ctlr, msg); return ret;
}
}
msg->optimized = true;
return 0;
}
/* * spi_maybe_optimize_message - optimize message if it isn't already pre-optimized * @spi: the device that will be used for the message * @msg: the message to optimize * Return: zero on success, else a negative error code
*/ staticint spi_maybe_optimize_message(struct spi_device *spi, struct spi_message *msg)
{ if (spi->controller->defer_optimize_message) {
msg->spi = spi; return 0;
}
if (msg->pre_optimized) return 0;
return __spi_optimize_message(spi, msg);
}
/** * spi_optimize_message - do any one-time validation and setup for a SPI message * @spi: the device that will be used for the message * @msg: the message to optimize * * Peripheral drivers that reuse the same message repeatedly may call this to * perform as much message prep as possible once, rather than repeating it each * time a message transfer is performed to improve throughput and reduce CPU * usage. * * Once a message has been optimized, it cannot be modified with the exception * of updating the contents of any xfer->tx_buf (the pointer can't be changed, * only the data in the memory it points to). * * Calls to this function must be balanced with calls to spi_unoptimize_message() * to avoid leaking resources. * * Context: can sleep * Return: zero on success, else a negative error code
*/ int spi_optimize_message(struct spi_device *spi, struct spi_message *msg)
{ int ret;
/* * Pre-optimization is not supported and optimization is deferred e.g. * when using spi-mux.
*/ if (spi->controller->defer_optimize_message) return 0;
ret = __spi_optimize_message(spi, msg); if (ret) return ret;
/* * This flag indicates that the peripheral driver called spi_optimize_message() * and therefore we shouldn't unoptimize message automatically when finalizing * the message but rather wait until spi_unoptimize_message() is called * by the peripheral driver.
*/
msg->pre_optimized = true;
/** * spi_unoptimize_message - releases any resources allocated by spi_optimize_message() * @msg: the message to unoptimize * * Calls to this function must be balanced with calls to spi_optimize_message(). * * Context: can sleep
*/ void spi_unoptimize_message(struct spi_message *msg)
{ if (msg->spi->controller->defer_optimize_message) return;
/** * devm_spi_optimize_message - managed version of spi_optimize_message() * @dev: the device that manages @msg (usually @spi->dev) * @spi: the device that will be used for the message * @msg: the message to optimize * Return: zero on success, else a negative error code * * spi_unoptimize_message() will automatically be called when the device is * removed.
*/ int devm_spi_optimize_message(struct device *dev, struct spi_device *spi, struct spi_message *msg)
{ int ret;
ret = spi_optimize_message(spi, msg); if (ret) return ret;
/** * spi_async - asynchronous SPI transfer * @spi: device with which data will be exchanged * @message: describes the data transfers, including completion callback * Context: any (IRQs may be blocked, etc) * * This call may be used in_irq and other contexts which can't sleep, * as well as from task contexts which can sleep. * * The completion callback is invoked in a context which can't sleep. * Before that invocation, the value of message->status is undefined. * When the callback is issued, message->status holds either zero (to * indicate complete success) or a negative error code. After that * callback returns, the driver which issued the transfer request may * deallocate the associated memory; it's no longer in use by any SPI * core or controller driver code. * * Note that although all messages to a spi_device are handled in * FIFO order, messages may go to different devices in other orders. * Some device might be higher priority, or have various "hard" access * time requirements, for example. * * On detection of any fault during the transfer, processing of * the entire message is aborted, and the device is deselected. * Until returning from the associated message completion callback, * no other spi_message queued to that device will be processed. * (This rule applies equally to all the synchronous transfer calls, * which are wrappers around this core asynchronous primitive.) * * Return: zero on success, else a negative error code.
*/ int spi_async(struct spi_device *spi, struct spi_message *message)
{ struct spi_controller *ctlr = spi->controller; int ret; unsignedlong flags;
ret = spi_maybe_optimize_message(spi, message); if (ret) return ret;
/* * Checking queue_empty here only guarantees async/sync message * ordering when coming from the same context. It does not need to * guard against reentrancy from a different context. The io_mutex * will catch those cases.
*/ if (READ_ONCE(ctlr->queue_empty) && !ctlr->must_async) {
message->actual_length = 0;
message->status = -EINPROGRESS;
/* * There are messages in the async queue that could have originated * from the same context, so we need to preserve ordering. * Therefor we send the message to the async queue and wait until they * are completed.
*/
message->complete = spi_complete;
message->context = &done;
spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
status = __spi_async(spi, message);
spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
if (status == 0) {
wait_for_completion(&done);
status = message->status;
}
message->complete = NULL;
message->context = NULL;
return status;
}
/** * spi_sync - blocking/synchronous SPI data transfers * @spi: device with which data will be exchanged * @message: describes the data transfers * Context: can sleep * * This call may only be used from a context that may sleep. The sleep * is non-interruptible, and has no timeout. Low-overhead controller * drivers may DMA directly into and out of the message buffers. * * Note that the SPI device's chip select is active during the message, * and then is normally disabled between messages. Drivers for some * frequently-used devices may want to minimize costs of selecting a chip, * by leaving it selected in anticipation that the next message will go * to the same chip. (That may increase power usage.) * * Also, the caller is guaranteeing that the memory associated with the * message will not be freed before this call returns. * * Return: zero on success, else a negative error code.
*/ int spi_sync(struct spi_device *spi, struct spi_message *message)
{ int ret;
mutex_lock(&spi->controller->bus_lock_mutex);
ret = __spi_sync(spi, message);
mutex_unlock(&spi->controller->bus_lock_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(spi_sync);
/** * spi_sync_locked - version of spi_sync with exclusive bus usage * @spi: device with which data will be exchanged * @message: describes the data transfers * Context: can sleep * * This call may only be used from a context that may sleep. The sleep * is non-interruptible, and has no timeout. Low-overhead controller * 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 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. * * Return: zero on success, else a negative error code.
*/ int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
{ return __spi_sync(spi, message);
}
EXPORT_SYMBOL_GPL(spi_sync_locked);
/** * spi_bus_lock - obtain a lock for exclusive SPI bus usage * @ctlr: SPI bus controller that should be locked for exclusive bus access * Context: can sleep * * This call may only be used from a context that may sleep. The sleep * is non-interruptible, and has no timeout. * * This call should be used by drivers that require exclusive access to the * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the * exclusive access is over. Data transfer must be done by spi_sync_locked * and spi_async_locked calls when the SPI bus lock is held. * * Return: always zero.
*/ int spi_bus_lock(struct spi_controller *ctlr)
{ unsignedlong flags;
/* Mutex remains locked until spi_bus_unlock() is called */
return 0;
}
EXPORT_SYMBOL_GPL(spi_bus_lock);
/** * spi_bus_unlock - release the lock for exclusive SPI bus usage * @ctlr: SPI bus controller that was locked for exclusive bus access * Context: can sleep * * This call may only be used from a context that may sleep. The sleep * is non-interruptible, and has no timeout. * * This call releases an SPI bus lock previously obtained by an spi_bus_lock * call. * * Return: always zero.
*/ int spi_bus_unlock(struct spi_controller *ctlr)
{
ctlr->bus_lock_flag = 0;
mutex_unlock(&ctlr->bus_lock_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(spi_bus_unlock);
/* Portable code must never pass more than 32 bytes */ #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
static u8 *buf;
/** * spi_write_then_read - SPI synchronous write followed by read * @spi: device with which data will be exchanged * @txbuf: data to be written (need not be DMA-safe) * @n_tx: size of txbuf, in bytes * @rxbuf: buffer into which data will be read (need not be DMA-safe) * @n_rx: size of rxbuf, in bytes * Context: can sleep * * This performs a half duplex MicroWire style transaction with the * device, sending txbuf and then reading rxbuf. The return value * is zero for success, else a negative errno status code. * This call may only be used from a context that may sleep. * * Parameters to this routine are always copied using a small buffer. * Performance-sensitive or bulk transfer code should instead use * spi_{async,sync}() calls with DMA-safe buffers. * * Return: zero on success, else a negative error code.
*/ int spi_write_then_read(struct spi_device *spi, constvoid *txbuf, unsigned n_tx, void *rxbuf, unsigned n_rx)
{ static DEFINE_MUTEX(lock);
int status; struct spi_message message; struct spi_transfer x[2];
u8 *local_buf;
/* * 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 || !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;
}
#if IS_ENABLED(CONFIG_OF_DYNAMIC) /* Must call put_device() when done with returned spi_device device */ staticstruct spi_device *of_find_spi_device_by_node(struct device_node *node)
{ struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
return dev ? to_spi_device(dev) : NULL;
}
/* The spi controllers are not using spi_bus, so we find it with another way */ staticstruct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
{ struct device *dev;
dev = class_find_device_by_of_node(&spi_controller_class, node); if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
dev = class_find_device_by_of_node(&spi_target_class, node); if (!dev) return NULL;
switch (of_reconfig_get_state_change(action, arg)) { case OF_RECONFIG_CHANGE_ADD:
ctlr = of_find_spi_controller_by_node(rd->dn->parent); if (ctlr == NULL) return NOTIFY_OK; /* Not for us */
if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
put_device(&ctlr->dev); return NOTIFY_OK;
}
/* * Clear the flag before adding the device so that fw_devlink * doesn't skip adding consumers to this device.
*/
rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE;
spi = of_register_spi_device(ctlr, rd->dn);
put_device(&ctlr->dev);
if (IS_ERR(spi)) {
pr_err("%s: failed to create for '%pOF'\n",
__func__, rd->dn);
of_node_clear_flag(rd->dn, OF_POPULATED); return notifier_from_errno(PTR_ERR(spi));
} break;
case OF_RECONFIG_CHANGE_REMOVE: /* Already depopulated? */ if (!of_node_check_flag(rd->dn, OF_POPULATED)) return NOTIFY_OK;
/* Find our device by node */
spi = of_find_spi_device_by_node(rd->dn); if (spi == NULL) return NOTIFY_OK; /* No? not meant for us */
/* Unregister takes one ref away */
spi_unregister_device(spi);
/* And put the reference of the find */
put_device(&spi->dev); break;
}
dev = class_find_device(&spi_controller_class, NULL, adev,
spi_acpi_controller_match); if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
dev = class_find_device(&spi_target_class, NULL, adev,
spi_acpi_controller_match); if (!dev) return NULL;
buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); if (!buf) {
status = -ENOMEM; goto err0;
}
status = bus_register(&spi_bus_type); if (status < 0) goto err1;
status = class_register(&spi_controller_class); if (status < 0) goto err2;
if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
status = class_register(&spi_target_class); if (status < 0) goto err3;
}
if (IS_ENABLED(CONFIG_OF_DYNAMIC))
WARN_ON(of_reconfig_notifier_register(&spi_of_notifier)); if (IS_ENABLED(CONFIG_ACPI))
WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
/* * A board_info is normally registered in arch_initcall(), * but even essential drivers wait till later. * * REVISIT only boardinfo really needs static linking. The rest (device and * driver registration) _could_ be dynamically linked (modular) ... Costs * include needing to have boardinfo data structures be much more public.
*/
postcore_initcall(spi_init);
Messung V0.5 in Prozent
¤ Dauer der Verarbeitung: 0.85 Sekunden
(vorverarbeitet am 2026-04-26)
¤
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