2023-09-12 14:54:33

by Martin Kaiser

[permalink] [raw]
Subject: [PATCH 2/2] hwrng: imx-rngc - reasonable timeout for initial seed

Set a more reasonable timeout for calculating the initial seed.

The reference manuals says that "The initial seed takes approximately
2,000,000 clock cycles." The rngc peripheral clock runs at >= 33.25MHz,
so seeding takes at most 60ms.

A timeout of 200ms is more appropriate than the current value of 3
seconds.

Signed-off-by: Martin Kaiser <[email protected]>
---
drivers/char/hw_random/imx-rngc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c
index 127c292dfbbf..118a72acb99b 100644
--- a/drivers/char/hw_random/imx-rngc.c
+++ b/drivers/char/hw_random/imx-rngc.c
@@ -51,9 +51,8 @@

#define RNGC_ERROR_STATUS_STAT_ERR 0x00000008

-#define RNGC_TIMEOUT 3000 /* 3 sec */
-
#define RNGC_SELFTEST_TIMEOUT 2500 /* us */
+#define RNGC_SEED_TIMEOUT 200 /* ms */

static bool self_test = true;
module_param(self_test, bool, 0);
@@ -184,7 +183,8 @@ static int imx_rngc_init(struct hwrng *rng)
cmd = readl(rngc->base + RNGC_COMMAND);
writel(cmd | RNGC_CMD_SEED, rngc->base + RNGC_COMMAND);

- ret = wait_for_completion_timeout(&rngc->rng_op_done, msecs_to_jiffies(RNGC_TIMEOUT));
+ ret = wait_for_completion_timeout(&rngc->rng_op_done,
+ msecs_to_jiffies(RNGC_SEED_TIMEOUT));
if (!ret) {
ret = -ETIMEDOUT;
goto err;
--
2.39.2