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>

diff --git a/drivers/char/hw_random/amd-rng.c b/drivers/char/hw_random/amd-rng.c
index bfa14b9a3a306d6e9dee38b48edd46c6dc9eaf0d..9959c762da2f8ec1f5cb0fde48021598f3deecfd 100644 (file)
--- 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)