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

Yendapally Reddy Dhananjaya Reddy
2016-05-23T16:20:51Z

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);
+ u32 num_words, count;

while ((__raw_readl(rng_base + RNG_STATUS) >> 24) == 0) {
if (!wait)
@@ -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);
+ if (num_words > max_words)
+ num_words = max_words;
+
+ for (count = 0; count < num_words; count++)
+ ((u32 *)buf)[count] = readl(rng_base + RNG_DATA);
+
+ return (num_words * sizeof(u32));
}

static struct hwrng bcm2835_rng_ops = {
--
2.1.0