[HWRNG]: move status polling loop to data_present callbacks

Handle waiting for new random within the drivers themselves, this allows to
use better suited timeouts for the individual rngs.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 12 insertions, 3 deletions

diff --git a/drivers/char/hw_random/intel-rng.c b/drivers/char/hw_random/intel-rng.c
index 753f46052b87..5cc651ef75eb 100644
--- a/drivers/char/hw_random/intel-rng.c
+++ b/drivers/char/hw_random/intel-rng.c
@@ -29,6 +29,7 @@
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/stop_machine.h>
+#include <linux/delay.h>
 #include <asm/io.h>
 
 
@@ -162,11 +163,19 @@ static inline u8 hwstatus_set(void __iomem *mem,
         return hwstatus_get(mem);
 }
 
-static int intel_rng_data_present(struct hwrng *rng)
+static int intel_rng_data_present(struct hwrng *rng, int wait)
 {
         void __iomem *mem = (void __iomem *)rng->priv;
-
-        return !!(readb(mem + INTEL_RNG_STATUS) & INTEL_RNG_DATA_PRESENT);
+        int data, i;
+
+        for (i = 0; i < 20; i++) {
+                data = !!(readb(mem + INTEL_RNG_STATUS) &
+                          INTEL_RNG_DATA_PRESENT);
+                if (data || !wait)
+                        break;
+                udelay(10);
+        }
+        return data;
 }
 
 static int intel_rng_data_read(struct hwrng *rng, u32 *data)