mmc: sandbox: Add support for writing

This adds support writing to the sandbox mmc backed by an in-memory
buffer. The unit test has been updated to test reading, writing, and
erasing. I'm not sure what MMCs erase to; I picked 0, but if it's 0xFF
then that can be easily changed.

Signed-off-by: Sean Anderson <sean.anderson@seco.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 14 insertions, 5 deletions

diff --git a/test/dm/mmc.c b/test/dm/mmc.c
index 4e5136c..f744452 100644
--- a/test/dm/mmc.c
+++ b/test/dm/mmc.c
@@ -29,16 +29,25 @@ static int dm_test_mmc_blk(struct unit_test_state *uts)
 {
 	struct udevice *dev;
 	struct blk_desc *dev_desc;
-	char cmp[1024];
+	int i;
+	char write[1024], read[1024];
 
 	ut_assertok(uclass_get_device(UCLASS_MMC, 0, &dev));
 	ut_assertok(blk_get_device_by_str("mmc", "0", &dev_desc));
 
-	/* Read a few blocks and look for the string we expect */
+	/* Write a few blocks and verify that we get the same data back */
 	ut_asserteq(512, dev_desc->blksz);
-	memset(cmp, '\0', sizeof(cmp));
-	ut_asserteq(2, blk_dread(dev_desc, 0, 2, cmp));
-	ut_assertok(strcmp(cmp, "this is a test"));
+	for (i = 0; i < sizeof(write); i++)
+		write[i] = i;
+	ut_asserteq(2, blk_dwrite(dev_desc, 0, 2, write));
+	ut_asserteq(2, blk_dread(dev_desc, 0, 2, read));
+	ut_asserteq_mem(write, read, sizeof(write));
+
+	/* Now erase them */
+	memset(write, '\0', sizeof(write));
+	ut_asserteq(2, blk_derase(dev_desc, 0, 2));
+	ut_asserteq(2, blk_dread(dev_desc, 0, 2, read));
+	ut_asserteq_mem(write, read, sizeof(write));
 
 	return 0;
 }