[PATCH 1/8] cmd: rng: fix error handling for dm_rng_read()

[Jamie Gibbons <jamie.gibbons@microchip.com>]

The rng command treated any non-zero return value from dm_rng_read() as
an error, even though the API returns the number of bytes read on
success.

Update the error handling to only report a failure when dm_rng_read()
returns a negative error code, or when a short read occurs.

This fixes false "Reading RNG failed" messages when RNG drivers
successfully return data.

Signed-off-by: Jamie Gibbons <jamie.gibbons@microchip.com>
---
 cmd/rng.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmd/rng.c b/cmd/rng.c
index 4d91094a8ec..18c0b6c9ca1 100644
--- a/cmd/rng.c
+++ b/cmd/rng.c
@@ -62,7 +62,7 @@ static int do_rng(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 	n = min(n, sizeof(buf));
 
 	err = dm_rng_read(dev, buf, n);
-	if (err) {
+	if (err < 0 || err != n) {
 		puts(err == -EINTR ? "Abort\n" : "Reading RNG failed\n");
 		ret = CMD_RET_FAILURE;
 	} else {
-- 
2.43.0