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spi: Add an helper to flush the message queue 

This is needed by the spi-mem logic to force all messages that have been
queued before a memory operation to be sent before we start the memory
operation. We do that in order to guarantee that spi-mem operations do
not preempt regular SPI transfers.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Boris Brezillon 2018-04-22 20:35:15 +02:00 committed by Mark Brown
parent 46336966bf
commit 988f259b46
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2 changed files with 18 additions and 0 deletions
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2
drivers/spi/internals.h
View File

@ -17,6 +17,8 @@
#include <linux/scatterlist.h>
#include <linux/spi/spi.h>
void spi_flush_queue(struct spi_controller *ctrl);
#ifdef CONFIG_HAS_DMA
int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
struct sg_table *sgt, void *buf, size_t len,

16
drivers/spi/spi.c
View File

@ -1522,6 +1522,22 @@ static int spi_controller_initialize_queue(struct spi_controller *ctlr)
return ret;
}
/**
* 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);
}
/*-------------------------------------------------------------------------*/
#if defined(CONFIG_OF)