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authorBoris Brezillon <boris.brezillon@bootlin.com>2018-04-22 20:35:15 +0200
committerMark Brown <broonie@kernel.org>2018-04-23 16:48:18 +0200
commit988f259b46646934003ff8ae4966f7233691d1ad (patch)
tree8065f35dce6e5c4fd910a03916625c8b74083ccd
parentspi: Expose spi_{map,unmap}_buf() for internal use (diff)
downloadlinux-988f259b46646934003ff8ae4966f7233691d1ad.tar.xz
linux-988f259b46646934003ff8ae4966f7233691d1ad.zip
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>
-rw-r--r--drivers/spi/internals.h2
-rw-r--r--drivers/spi/spi.c16
2 files changed, 18 insertions, 0 deletions
diff --git a/drivers/spi/internals.h b/drivers/spi/internals.h
index dbe56c77b464..4a28a8395552 100644
--- a/drivers/spi/internals.h
+++ b/drivers/spi/internals.h
@@ -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,
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 86b778d8563e..3f4666365678 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1522,6 +1522,22 @@ err_init_queue:
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)