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authorMark Brown <broonie@kernel.org>2019-07-04 17:35:11 +0100
committerMark Brown <broonie@kernel.org>2019-07-04 17:35:11 +0100
commit26ac56506b0ea598bd0b52dcbd2d697282af98ed (patch)
tree821c8c51c7077d45c1a9eac06a1d43307ca91975
parent106dbe24d4146c0804cb025e450ac7af42d72356 (diff)
parent924b5867e7bd6a6a98014f0517b747465b108011 (diff)
Merge remote-tracking branch 'spi/topic/pump-rt' into spi-next
-rw-r--r--drivers/spi/spi.c36
-rw-r--r--include/linux/spi/spi.h2
2 files changed, 32 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, " : "",
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 0ec11f2911af..af4f265d0f67 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -109,6 +109,7 @@ void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
* This may be changed by the device's driver, or left at the
* default (0) indicating protocol words are eight bit bytes.
* The spi_transfer.bits_per_word can override this for each transfer.
+ * @rt: Make the pump thread real time priority.
* @irq: Negative, or the number passed to request_irq() to receive
* interrupts from this device.
* @controller_state: Controller's runtime state
@@ -143,6 +144,7 @@ struct spi_device {
u32 max_speed_hz;
u8 chip_select;
u8 bits_per_word;
+ bool rt;
u32 mode;
#define SPI_CPHA 0x01 /* clock phase */
#define SPI_CPOL 0x02 /* clock polarity */