[PATCH 7/8] spi: loopback-test: add option to use vmalloc'ed buffers

[Frode Isaksen <fisaksen@baylibre.com>]

Using vmalloc'ed buffers will use one SG entry for each page,
that may provoke DMA errors for large transfers.
Also vmalloc'ed buffers may cause errors on CPU's with VIVT cache.
Add this option to catch these errors when testing.

Signed-off-by: Frode Isaksen <fisaksen@baylibre.com>
---
 drivers/spi/spi-loopback-test.c | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-loopback-test.c b/drivers/spi/spi-loopback-test.c
index ce552af..5618df3 100644
--- a/drivers/spi/spi-loopback-test.c
+++ b/drivers/spi/spi-loopback-test.c
@@ -55,6 +55,12 @@ module_param(run_only_test, int, 0);
 MODULE_PARM_DESC(run_only_test,
 		 "only run the test with this number (0-based !)");
 
+/* use vmalloc'ed buffers */
+int use_vmalloc;
+module_param(use_vmalloc, int, 0644);
+MODULE_PARM_DESC(use_vmalloc,
+		 "use vmalloc'ed buffers instead of kmalloc'ed");
+
 /* the actual tests to execute */
 static struct spi_test spi_tests[] = {
 	{
@@ -970,13 +976,19 @@ int spi_test_run_tests(struct spi_device *spi,
 	/* allocate rx/tx buffers of 128kB size without devm
 	 * in the hope that is on a page boundary
 	 */
-	rx = kzalloc(SPI_TEST_MAX_SIZE_PLUS, GFP_KERNEL);
+	if (use_vmalloc)
+		rx = vmalloc(SPI_TEST_MAX_SIZE_PLUS);
+	else
+		rx = kzalloc(SPI_TEST_MAX_SIZE_PLUS, GFP_KERNEL);
 	if (!rx) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
-	tx = kzalloc(SPI_TEST_MAX_SIZE_PLUS, GFP_KERNEL);
+	if (use_vmalloc)
+		tx = vmalloc(SPI_TEST_MAX_SIZE_PLUS);
+	else
+		tx = kzalloc(SPI_TEST_MAX_SIZE_PLUS, GFP_KERNEL);
 	if (!tx) {
 		ret = -ENOMEM;
 		goto out;
@@ -1004,8 +1016,13 @@ int spi_test_run_tests(struct spi_device *spi,
 	}
 
 out:
-	kfree(rx);
-	kfree(tx);
+	if (use_vmalloc) {
+		vfree(rx);
+		vfree(tx);
+	} else {
+		kfree(rx);
+		kfree(tx);
+	}
 	return ret;
 }
 EXPORT_SYMBOL_GPL(spi_test_run_tests);
-- 
2.7.4