[HWRNG]: move status polling loop to data_present callbacks

[powerpc.git] / drivers / char / hw_random / via-rng.c

diff --git a/drivers/char/hw_random/via-rng.c b/drivers/char/hw_random/via-rng.c
index ec435cb..868e39f 100644 (file)
--- 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)