[PATCH 4/4] hwrng: bcm2835: Read as much data as available

Eric Anholt
2016-05-24T02:21:00Z

Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>
writes:

> Read the requested number of data from the fifo
>
> Signed-off-by: Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>
> ---
> drivers/char/hw_random/bcm2835-rng.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c
> index b1e8b78..9bbdc07 100644
> --- a/drivers/char/hw_random/bcm2835-rng.c
> +++ b/drivers/char/hw_random/bcm2835-rng.c
> @@ -43,6 +43,8 @@ static int bcm2835_rng_read(struct hwrng *rng, void *buf, size_t max,
> bool wait)
> {
> void __iomem *rng_base = (void __iomem *)rng->priv;
> + u32 max_words = max/sizeof(u32);

Style fix: Binary operators get a space on each side, so
"max / sizeof(u32);"

> @@ -50,8 +52,14 @@ static int bcm2835_rng_read(struct hwrng *rng, void *buf, size_t max,
> cpu_relax();
> }
>
> - *(u32 *)buf = __raw_readl(rng_base + RNG_DATA);
> - return sizeof(u32);
> + num_words = (readl(rng_base + RNG_STATUS) >> 24);

Optional cleanup: here and in the return statement, drop the extra
parenthesis.

Functionality-wise, this patch looks great to me, and should make the
driver more efficient. With at least the binary operators change done,
it will be:

Reviewed-by: Eric Anholt <eric@anholt.net>

Thanks!
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