[PATCH 5.13 333/351] firmware: turris-mox-rwtm: fail probing when firmware does not support hwrng

Greg Kroah-Hartman
2021-07-19T17:48:15Z

From: Pali Rohár <pali@kernel.org>

[ Upstream commit 2eab59cf0d2036a5a9e264f719b71c21ccf679c2 ]

When Marvell's rWTM firmware, which does not support the GET_RANDOM
command, is used, kernel prints an error message
hwrng: no data available
every 10 seconds.

Fail probing of this driver if the rWTM firmware does not support the
GET_RANDOM command.

Fixes: 389711b37493 ("firmware: Add Turris Mox rWTM firmware driver")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/firmware/turris-mox-rwtm.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)

diff --git a/drivers/firmware/turris-mox-rwtm.c b/drivers/firmware/turris-mox-rwtm.c
index d7e3489e4bf2..3ef9687dddca 100644
--- a/drivers/firmware/turris-mox-rwtm.c
+++ b/drivers/firmware/turris-mox-rwtm.c
@@ -260,6 +260,27 @@ static int mox_get_board_info(struct mox_rwtm *rwtm)
return 0;
}

+static int check_get_random_support(struct mox_rwtm *rwtm)
+{
+ struct armada_37xx_rwtm_tx_msg msg;
+ int ret;
+
+ msg.command = MBOX_CMD_GET_RANDOM;
+ msg.args[0] = 1;
+ msg.args[1] = rwtm->buf_phys;
+ msg.args[2] = 4;
+
+ ret = mbox_send_message(rwtm->mbox, &msg);
+ if (ret < 0)
+ return ret;
+
+ ret = wait_for_completion_timeout(&rwtm->cmd_done, HZ / 2);
+ if (ret < 0)
+ return ret;
+
+ return mox_get_status(MBOX_CMD_GET_RANDOM, rwtm->reply.retval);
+}
+
static int mox_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
{
struct mox_rwtm *rwtm = (struct mox_rwtm *) rng->priv;
@@ -497,6 +518,13 @@ static int turris_mox_rwtm_probe(struct platform_device *pdev)
if (ret < 0)
dev_warn(dev, "Cannot read board information: %i\n", ret);

+ ret = check_get_random_support(rwtm);
+ if (ret < 0) {
+ dev_notice(dev,
+ "Firmware does not support the GET_RANDOM command\n");
+ goto free_channel;
+ }
+
rwtm->hwrng.name = DRIVER_NAME "_hwrng";
rwtm->hwrng.read = mox_hwrng_read;
rwtm->hwrng.priv = (unsigned long) rwtm;
--
2.30.2