[PATCH 1/4] spi: spi-loopback-test: Add test to trigger DMA/PIO mixing

[Vincent Whitchurch <vincent.whitchurch@xxxxxxxx>]

Add a test where a small and a large transfer in a message hit the same
cache line.  This test currently fails on spi-s3c64xx on in DMA mode
since it ends up mixing DMA and PIO without proper cache maintenance.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@xxxxxxxx>
---
 drivers/spi/spi-loopback-test.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/spi/spi-loopback-test.c b/drivers/spi/spi-loopback-test.c
index 4d4f77a186a9..dd7de8fa37d0 100644
--- a/drivers/spi/spi-loopback-test.c
+++ b/drivers/spi/spi-loopback-test.c
@@ -313,6 +313,33 @@ static struct spi_test spi_tests[] = {
 			},
 		},
 	},
+	{
+		.description	= "three tx+rx transfers with overlapping cache lines",
+		.fill_option	= FILL_COUNT_8,
+		/*
+		 * This should be large enough for the controller driver to
+		 * choose to transfer it with DMA.
+		 */
+		.iterate_len    = { 512, -1 },
+		.iterate_transfer_mask = BIT(1),
+		.transfer_count = 3,
+		.transfers		= {
+			{
+				.len = 1,
+				.tx_buf = TX(0),
+				.rx_buf = RX(0),
+			},
+			{
+				.tx_buf = TX(1),
+				.rx_buf = RX(1),
+			},
+			{
+				.len = 1,
+				.tx_buf = TX(513),
+				.rx_buf = RX(513),
+			},
+		},
+	},
 
 	{ /* end of tests sequence */ }
 };
-- 
2.34.1