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 <martin@kaiser.cx>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c
index 127c292dfbbfbfd53502ce45b25f5b22b8a55b69..118a72acb99b40cbe5b8ab2b2b739a04ce6a8b15 100644 (file)
--- 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;