diff options
Diffstat (limited to 'drivers/char/hw_random/via-rng.c')
| -rw-r--r-- | drivers/char/hw_random/via-rng.c | 19 |
1 files changed, 12 insertions, 7 deletions
diff --git a/drivers/char/hw_random/via-rng.c b/drivers/char/hw_random/via-rng.c index ec435cb25c4..868e39fd42e 100644 --- a/drivers/char/hw_random/via-rng.c +++ b/drivers/char/hw_random/via-rng.c @@ -27,6 +27,7 @@ #include <linux/module.h> #include <linux/kernel.h> #include <linux/hw_random.h> +#include <linux/delay.h> #include <asm/io.h> #include <asm/msr.h> #include <asm/cpufeature.h> @@ -77,10 +78,11 @@ static inline u32 xstore(u32 *addr, u32 edx_in) return eax_out; } -static int via_rng_data_present(struct hwrng *rng) +static int via_rng_data_present(struct hwrng *rng, int wait) { u32 bytes_out; u32 *via_rng_datum = (u32 *)(&rng->priv); + int i; /* We choose the recommended 1-byte-per-instruction RNG rate, * for greater randomness at the expense of speed. Larger @@ -95,12 +97,15 @@ static int via_rng_data_present(struct hwrng *rng) * completes. */ - *via_rng_datum = 0; /* paranoia, not really necessary */ - bytes_out = xstore(via_rng_datum, VIA_RNG_CHUNK_1); - bytes_out &= VIA_XSTORE_CNT_MASK; - if (bytes_out == 0) - return 0; - return 1; + for (i = 0; i < 20; i++) { + *via_rng_datum = 0; /* paranoia, not really necessary */ + bytes_out = xstore(via_rng_datum, VIA_RNG_CHUNK_1); + bytes_out &= VIA_XSTORE_CNT_MASK; + if (bytes_out || !wait) + break; + udelay(10); + } + return bytes_out ? 1 : 0; } static int via_rng_data_read(struct hwrng *rng, u32 *data) |