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path: root/drivers/spi/spi.c
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Diffstat (limited to 'drivers/spi/spi.c')
-rw-r--r--drivers/spi/spi.c36
1 files changed, 30 insertions, 6 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 81e4d9f7c0f4..91673351bcf3 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1417,10 +1417,32 @@ static void spi_pump_messages(struct kthread_work *work)
__spi_pump_messages(ctlr, true);
}
-static int spi_init_queue(struct spi_controller *ctlr)
+/**
+ * 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.
+ */
+static void spi_set_thread_rt(struct spi_controller *ctlr)
{
struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
+ dev_info(&ctlr->dev,
+ "will run message pump with realtime priority\n");
+ sched_setscheduler(ctlr->kworker_task, SCHED_FIFO, &param);
+}
+
+static int spi_init_queue(struct spi_controller *ctlr)
+{
ctlr->running = false;
ctlr->busy = false;
@@ -1440,11 +1462,8 @@ static int spi_init_queue(struct spi_controller *ctlr)
* request and the scheduling of the message pump thread. Without this
* setting the message pump thread will remain at default priority.
*/
- if (ctlr->rt) {
- dev_info(&ctlr->dev,
- "will run message pump with realtime priority\n");
- sched_setscheduler(ctlr->kworker_task, SCHED_FIFO, &param);
- }
+ if (ctlr->rt)
+ spi_set_thread_rt(ctlr);
return 0;
}
@@ -3071,6 +3090,11 @@ int spi_setup(struct spi_device *spi)
spi_set_cs(spi, false);
+ if (spi->rt && !spi->controller->rt) {
+ spi->controller->rt = true;
+ spi_set_thread_rt(spi->controller);
+ }
+
dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
(int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
(spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",