[PATCH v4 2/4] spi: Split spi message into max_dma_len size chunks

[Noralf Trønnes <noralf@xxxxxxxxxxx>]

From: Meghana Madhyastha <meghana.madhyastha@xxxxxxxxx>

Some drivers like spi_bcm2835 have a max size on DMA transfers. Work
around this by splitting up the transfer if necessary.

->max_transfer_size is MAX_INT if the driver doesn't set it, so this change
will only affect drivers that set the value.

Signed-off-by: Meghana Madhyastha <meghana.madhyastha@xxxxxxxxx>
Signed-off-by: Noralf Trønnes <noralf@xxxxxxxxxxx>
---
 drivers/spi/spi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 05875e63be43..22bc658032b3 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1299,6 +1299,11 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
 
 	trace_spi_message_start(ctlr->cur_msg);
 
+	ret = spi_split_transfers_maxsize(ctlr, ctlr->cur_msg, ctlr->max_dma_len,
+					  GFP_KERNEL | GFP_DMA);
+	if (ret)
+		goto out;
+
 	if (ctlr->prepare_message) {
 		ret = ctlr->prepare_message(ctlr, ctlr->cur_msg);
 		if (ret) {
-- 
2.20.1