hwrng: core - Replace u32 in driver API with byte array

This patch implements a new method by which hw_random hardware drivers
can pass data to the core more efficiently, using a shared buffer.

The old methods have been retained as a compatability layer until all the
drivers have been updated.

Signed-off-by: Ian Molton <ian.molton@collabora.co.uk>
Acked-by: Matt Mackall <mpm@selenic.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 5 insertions, 2 deletions

diff --git a/include/linux/hw_random.h b/include/linux/hw_random.h
index 7244456e7e65..9bede7633f74 100644
--- a/include/linux/hw_random.h
+++ b/include/linux/hw_random.h
@@ -22,10 +22,12 @@
  * @cleanup:            Cleanup callback (can be NULL).
  * @data_present:       Callback to determine if data is available
  *                      on the RNG. If NULL, it is assumed that
- *                      there is always data available.
+ *                      there is always data available.  *OBSOLETE*
  * @data_read:          Read data from the RNG device.
  *                      Returns the number of lower random bytes in "data".
- *                      Must not be NULL.
+ *                      Must not be NULL.    *OSOLETE*
+ * @read:               New API. drivers can fill up to max bytes of data
+ *                      into the buffer. The buffer is aligned for any type.
  * @priv:               Private data, for use by the RNG driver.
  */
 struct hwrng {
@@ -34,6 +36,7 @@ struct hwrng {
         void (*cleanup)(struct hwrng *rng);
         int (*data_present)(struct hwrng *rng, int wait);
         int (*data_read)(struct hwrng *rng, u32 *data);
+        int (*read)(struct hwrng *rng, void *data, size_t max, bool wait);
         unsigned long priv;
 
         /* internal. */