spi: core: add spi_split_transfers_maxsize
Add spi_split_transfers_maxsize method that splits
spi_transfers transparently into multiple transfers
that are below the given max-size.
This makes use of the spi_res framework via
spi_replace_transfers to allocate/free the extra
transfers as well as reverting back the changes applied
while processing the spi_message.
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index d713857..3c02b4d 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -53,6 +53,10 @@
*
* @transfer_bytes_histo:
* transfer bytes histogramm
+ *
+ * @transfers_split_maxsize:
+ * number of transfers that have been split because of
+ * maxsize limit
*/
struct spi_statistics {
spinlock_t lock; /* lock for the whole structure */
@@ -72,6 +76,8 @@
#define SPI_STATISTICS_HISTO_SIZE 17
unsigned long transfer_bytes_histo[SPI_STATISTICS_HISTO_SIZE];
+
+ unsigned long transfers_split_maxsize;
};
void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
@@ -935,6 +941,15 @@
/*---------------------------------------------------------------------------*/
+/* SPI transfer transformation methods */
+
+extern int spi_split_transfers_maxsize(struct spi_master *master,
+ struct spi_message *msg,
+ size_t maxsize,
+ gfp_t gfp);
+
+/*---------------------------------------------------------------------------*/
+
/* All these synchronous SPI transfer routines are utilities layered
* over the core async transfer primitive. Here, "synchronous" means
* they will sleep uninterruptibly until the async transfer completes.
