Merge commit 'v2.6.27-rc3' into x86/prototypes

[sfrench/cifs-2.6.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 ec435cb25c4fd4709f58c47d4f3ce9153b2748ca..f7feae4ebb5e9981e7f730f637a2b1e54f5cc767 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>
@@ -41,6 +42,8 @@ enum {
        VIA_STRFILT_ENABLE      = (1 << 14),
        VIA_RAWBITS_ENABLE      = (1 << 13),
        VIA_RNG_ENABLE          = (1 << 6),
+       VIA_NOISESRC1           = (1 << 8),
+       VIA_NOISESRC2           = (1 << 9),
        VIA_XSTORE_CNT_MASK     = 0x0F,
 
        VIA_RNG_CHUNK_8         = 0x00, /* 64 rand bits, 64 stored bits */
@@ -77,10 +80,11 @@ 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 +99,15 @@ 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)
@@ -114,6 +121,7 @@ static int via_rng_data_read(struct hwrng *rng, u32 *data)
 
 static int via_rng_init(struct hwrng *rng)
 {
+       struct cpuinfo_x86 *c = &cpu_data(0);
        u32 lo, hi, old_lo;
 
        /* Control the RNG via MSR.  Tread lightly and pay very close
@@ -129,6 +137,17 @@ static int via_rng_init(struct hwrng *rng)
        lo &= ~VIA_XSTORE_CNT_MASK;
        lo &= ~(VIA_STRFILT_ENABLE | VIA_STRFILT_FAIL | VIA_RAWBITS_ENABLE);
        lo |= VIA_RNG_ENABLE;
+       lo |= VIA_NOISESRC1;
+
+       /* Enable secondary noise source on CPUs where it is present. */
+
+       /* Nehemiah stepping 8 and higher */
+       if ((c->x86_model == 9) && (c->x86_mask > 7))
+               lo |= VIA_NOISESRC2;
+
+       /* Esther */
+       if (c->x86_model >= 10)
+               lo |= VIA_NOISESRC2;
 
        if (lo != old_lo)
                wrmsr(MSR_VIA_RNG, lo, hi);