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spi: Allow setting pump to RT priority

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Merge tag 'spi-rt-pump' into chrome-platform/for-next

Immutable branch between spi and chrome-platform for driver changes to
allow setting spi pump to RT priority.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
This commit is contained in:
Enric Balletbo i Serra 2019-05-24 11:30:17 +02:00
commit 2a5f857291
2 changed files with 32 additions and 6 deletions
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36
drivers/spi/spi.c
View File

@ -1364,10 +1364,32 @@ 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;
@ -1387,11 +1409,8 @@ 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;
}
@ -2982,6 +3001,11 @@ 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, " : "",

2
include/linux/spi/spi.h
View File

@ -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 */