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| author |   Matt Porter <mporter@linaro.org> | 2014-04-10 15:22:10 -0400 |
|---|---|---|
| committer |   Herbert Xu <herbert@gondor.apana.org.au> | 2014-04-11 11:31:13 +0800 |
| commit | eb4a5346e777784f1b5ae9fd0c29b96344bdc3ae (patch) | |
| tree | 9803168c7b40fd074d3140436547a58c6c0365dd /drivers/char/hw_random/bcm2835-rng.c | |
| parent | Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 (diff) | |
| download | linux-dev-eb4a5346e777784f1b5ae9fd0c29b96344bdc3ae.tar.xz linux-dev-eb4a5346e777784f1b5ae9fd0c29b96344bdc3ae.zip | |
hwrng: bcm2835 - fix oops when rng h/w is accessed during registration
Commit "d9e7972 hwrng: add randomness to system from rng sources"
exposed a bug in the bcm2835-rng driver resulting in boot failure
on Raspberry Pi due to the following oops:
[ 28.261523] BUG: soft lockup - CPU#0 stuck for 23s! [swapper:1]
[ 28.271058]
[ 28.275958] CPU: 0 PID: 1 Comm: swapper Not tainted 3.14.0+ #11
[ 28.285374] task: db480000 ti: db484000 task.ti: db484000
[ 28.294279] PC is at bcm2835_rng_read+0x28/0x48
[ 28.302276] LR is at hwrng_register+0x1a8/0x238
.
.
.
The RNG h/w is not completely initialized and enabled before
hwrng_register() is called and so the bcm2835_rng_read() fails.
Fix this by making the warmup/enable writes before registering
the RNG source with the hwrng core.
Signed-off-by: Matt Porter <mporter@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'drivers/char/hw_random/bcm2835-rng.c')
| -rw-r--r-- | drivers/char/hw_random/bcm2835-rng.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c index 8c3b255e629a..e900961cdd2e 100644 --- a/drivers/char/hw_random/bcm2835-rng.c +++ b/drivers/char/hw_random/bcm2835-rng.c @@ -61,18 +61,18 @@ static int bcm2835_rng_probe(struct platform_device *pdev) } bcm2835_rng_ops.priv = (unsigned long)rng_base; + /* set warm-up count & enable */ + __raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS); + __raw_writel(RNG_RBGEN, rng_base + RNG_CTRL); + /* register driver */ err = hwrng_register(&bcm2835_rng_ops); if (err) { dev_err(dev, "hwrng registration failed\n"); iounmap(rng_base); - } else { + } else dev_info(dev, "hwrng registered\n"); - /* set warm-up count & enable */ - __raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS); - __raw_writel(RNG_RBGEN, rng_base + RNG_CTRL); - } return err; } |