aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/spi/spi.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/spi/spi.c')
-rw-r--r--drivers/spi/spi.c96
1 files changed, 73 insertions, 23 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 8158e281f354..dc12af018350 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -475,6 +475,12 @@ static LIST_HEAD(spi_controller_list);
*/
static DEFINE_MUTEX(board_lock);
+/*
+ * Prevents addition of devices with same chip select and
+ * addition of devices below an unregistering controller.
+ */
+static DEFINE_MUTEX(spi_add_lock);
+
/**
* spi_alloc_device - Allocate a new SPI device
* @ctlr: Controller to which device is connected
@@ -554,7 +560,6 @@ static int spi_dev_check(struct device *dev, void *data)
*/
int spi_add_device(struct spi_device *spi)
{
- static DEFINE_MUTEX(spi_add_lock);
struct spi_controller *ctlr = spi->controller;
struct device *dev = ctlr->dev.parent;
int status;
@@ -582,6 +587,13 @@ int spi_add_device(struct spi_device *spi)
goto done;
}
+ /* Controller may unregister concurrently */
+ if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
+ !device_is_registered(&ctlr->dev)) {
+ status = -ENODEV;
+ goto done;
+ }
+
/* Descriptors take precedence */
if (ctlr->cs_gpiods)
spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
@@ -778,6 +790,17 @@ static void spi_set_cs(struct spi_device *spi, bool enable)
{
bool enable1 = enable;
+ /*
+ * Avoid calling into the driver (or doing delays) if the chip select
+ * isn't actually changing from the last time this was called.
+ */
+ if ((spi->controller->last_cs_enable == enable) &&
+ (spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
+ return;
+
+ spi->controller->last_cs_enable = enable;
+ spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
+
if (!spi->controller->set_cs_timing) {
if (enable1)
spi_delay_exec(&spi->controller->cs_setup, NULL);
@@ -982,6 +1005,8 @@ static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
}
+ ctlr->cur_msg_mapped = false;
+
return 0;
}
#else /* !CONFIG_HAS_DMA */
@@ -1234,8 +1259,17 @@ static int spi_transfer_one_message(struct spi_controller *ctlr,
if (xfer->tx_buf || xfer->rx_buf) {
reinit_completion(&ctlr->xfer_completion);
+fallback_pio:
ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
if (ret < 0) {
+ if (ctlr->cur_msg_mapped &&
+ (xfer->error & SPI_TRANS_FAIL_NO_START)) {
+ __spi_unmap_msg(ctlr, msg);
+ ctlr->fallback = true;
+ xfer->error &= ~SPI_TRANS_FAIL_NO_START;
+ goto fallback_pio;
+ }
+
SPI_STATISTICS_INCREMENT_FIELD(statm,
errors);
SPI_STATISTICS_INCREMENT_FIELD(stats,
@@ -1314,6 +1348,14 @@ void spi_finalize_current_transfer(struct spi_controller *ctlr)
}
EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
+static void spi_idle_runtime_pm(struct spi_controller *ctlr)
+{
+ if (ctlr->auto_runtime_pm) {
+ pm_runtime_mark_last_busy(ctlr->dev.parent);
+ pm_runtime_put_autosuspend(ctlr->dev.parent);
+ }
+}
+
/**
* __spi_pump_messages - function which processes spi message queue
* @ctlr: controller to process queue for
@@ -1346,7 +1388,7 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
/* If another context is idling the device then defer */
if (ctlr->idling) {
- kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
+ kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
return;
}
@@ -1358,10 +1400,17 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
return;
}
- /* Only do teardown in the thread */
+ /* Defer any non-atomic teardown to the thread */
if (!in_kthread) {
- kthread_queue_work(&ctlr->kworker,
- &ctlr->pump_messages);
+ if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
+ !ctlr->unprepare_transfer_hardware) {
+ spi_idle_runtime_pm(ctlr);
+ ctlr->busy = false;
+ trace_spi_controller_idle(ctlr);
+ } else {
+ kthread_queue_work(ctlr->kworker,
+ &ctlr->pump_messages);
+ }
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
return;
}
@@ -1378,10 +1427,7 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
ctlr->unprepare_transfer_hardware(ctlr))
dev_err(&ctlr->dev,
"failed to unprepare transfer hardware\n");
- if (ctlr->auto_runtime_pm) {
- pm_runtime_mark_last_busy(ctlr->dev.parent);
- pm_runtime_put_autosuspend(ctlr->dev.parent);
- }
+ spi_idle_runtime_pm(ctlr);
trace_spi_controller_idle(ctlr);
spin_lock_irqsave(&ctlr->queue_lock, flags);
@@ -1592,11 +1638,9 @@ EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
*/
static void spi_set_thread_rt(struct spi_controller *ctlr)
{
- struct sched_param param = { .sched_priority = MAX_RT_PRIO / 2 };
-
dev_info(&ctlr->dev,
"will run message pump with realtime priority\n");
- sched_setscheduler(ctlr->kworker_task, SCHED_FIFO, &param);
+ sched_set_fifo(ctlr->kworker->task);
}
static int spi_init_queue(struct spi_controller *ctlr)
@@ -1604,13 +1648,12 @@ static int spi_init_queue(struct spi_controller *ctlr)
ctlr->running = false;
ctlr->busy = false;
- kthread_init_worker(&ctlr->kworker);
- ctlr->kworker_task = kthread_run(kthread_worker_fn, &ctlr->kworker,
- "%s", dev_name(&ctlr->dev));
- if (IS_ERR(ctlr->kworker_task)) {
- dev_err(&ctlr->dev, "failed to create message pump task\n");
- return PTR_ERR(ctlr->kworker_task);
+ ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
+ if (IS_ERR(ctlr->kworker)) {
+ dev_err(&ctlr->dev, "failed to create message pump kworker\n");
+ return PTR_ERR(ctlr->kworker);
}
+
kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
/*
@@ -1693,7 +1736,8 @@ void spi_finalize_current_message(struct spi_controller *ctlr)
spin_lock_irqsave(&ctlr->queue_lock, flags);
ctlr->cur_msg = NULL;
ctlr->cur_msg_prepared = false;
- kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
+ ctlr->fallback = false;
+ kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
trace_spi_message_done(mesg);
@@ -1719,7 +1763,7 @@ static int spi_start_queue(struct spi_controller *ctlr)
ctlr->cur_msg = NULL;
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
- kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
+ kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
return 0;
}
@@ -1775,8 +1819,7 @@ static int spi_destroy_queue(struct spi_controller *ctlr)
return ret;
}
- kthread_flush_worker(&ctlr->kworker);
- kthread_stop(ctlr->kworker_task);
+ kthread_destroy_worker(ctlr->kworker);
return 0;
}
@@ -1799,7 +1842,7 @@ static int __spi_queued_transfer(struct spi_device *spi,
list_add_tail(&msg->queue, &ctlr->queue);
if (!ctlr->busy && need_pump)
- kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
+ kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
return 0;
@@ -2764,6 +2807,10 @@ 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(&spi_add_lock);
+
device_for_each_child(&ctlr->dev, NULL, __unregister);
/* First make sure that this controller was ever added */
@@ -2784,6 +2831,9 @@ void spi_unregister_controller(struct spi_controller *ctlr)
if (found == ctlr)
idr_remove(&spi_master_idr, id);
mutex_unlock(&board_lock);
+
+ if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
+ mutex_unlock(&spi_add_lock);
}
EXPORT_SYMBOL_GPL(spi_unregister_controller);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.