diff options
| author | Corentin LABBE <clabbe.montjoie@gmail.com> | 2016-08-26 14:11:36 +0300 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2016-08-31 18:00:47 +0300 |
| commit | 85962d2248fae84ffaa04f09826596d20af56819 (patch) | |
| tree | 6bc4f8c63a5a1680fe7db850a20ae9a7fea4d79f /drivers/char | |
| parent | 3c343a37644c5fe07960c3226a463d98627607f0 (diff) | |
| download | linux-85962d2248fae84ffaa04f09826596d20af56819.tar.xz | |
hwrng: amd - Convert to new hwrng read() API
This patch convert the hwrng interface used by amd768-rng to its new API
by replacing data_read()/data_present() by read().
Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/hw_random/amd-rng.c | 47 |
1 files changed, 28 insertions, 19 deletions
diff --git a/drivers/char/hw_random/amd-rng.c b/drivers/char/hw_random/amd-rng.c index bfa14b9a3a30..9959c762da2f 100644 --- a/drivers/char/hw_random/amd-rng.c +++ b/drivers/char/hw_random/amd-rng.c @@ -58,27 +58,37 @@ struct amd768_priv { u32 pmbase; }; -static int amd_rng_data_present(struct hwrng *rng, int wait) +static int amd_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) { + u32 *data = buf; struct amd768_priv *priv = (struct amd768_priv *)rng->priv; - int data, i; - - for (i = 0; i < 20; i++) { - data = !!(ioread32(priv->iobase + RNGDONE) & 1); - if (data || !wait) - break; - udelay(10); + size_t read = 0; + /* We will wait at maximum one time per read */ + int timeout = max / 4 + 1; + + /* + * RNG data is available when RNGDONE is set to 1 + * New random numbers are generated approximately 128 microseconds + * after RNGDATA is read + */ + while (read < max) { + if (ioread32(priv->iobase + RNGDONE) == 0) { + if (wait) { + /* Delay given by datasheet */ + usleep_range(128, 196); + if (timeout-- == 0) + return read; + } else { + return 0; + } + } else { + *data = ioread32(priv->iobase + RNGDATA); + data++; + read += 4; + } } - return data; -} - -static int amd_rng_data_read(struct hwrng *rng, u32 *data) -{ - struct amd768_priv *priv = (struct amd768_priv *)rng->priv; - - *data = ioread32(priv->iobase + RNGDATA); - return 4; + return read; } static int amd_rng_init(struct hwrng *rng) @@ -111,8 +121,7 @@ static struct hwrng amd_rng = { .name = "amd", .init = amd_rng_init, .cleanup = amd_rng_cleanup, - .data_present = amd_rng_data_present, - .data_read = amd_rng_data_read, + .read = amd_rng_read, }; static int __init mod_init(void) |