Support VIA Nano hardware RNG
The VIA Nano CPU supports the same XSTORE instruction based RNG,
but it lacks the MSR present in earlier CPUs.
Signed-off-by: Harald Welte <haraldwe...@viatech.com>
diff --git a/drivers/char/hw_random/via-rng.c b/drivers/char/hw_random/via-rng.c
index 4e9573c..794aacb 100644
--- a/drivers/char/hw_random/via-rng.c
+++ b/drivers/char/hw_random/via-rng.c
@@ -132,6 +132,19 @@ static int via_rng_init(struct hwrng *rng)
struct cpuinfo_x86 *c = &cpu_data(0);
u32 lo, hi, old_lo;
+ /* VIA Nano CPUs don't have the MSR_VIA_RNG anymore. The RNG
+ * is always enabled if CPUID rng_en is set. There is no
+ * RNG configuration like it used to be the case in this
+ * register */
+ if ((c->x86 == 6) && (c->x86_model >= 0x0f)) {
+ if (!cpu_has_xstore_enabled) {
+ printk(KERN_ERR PFX "can't enable hardware RNG "
+ "if XSTORE is not enabled\n");
+ return -ENODEV;
+ }
+ return 0;
+ }
+
/* Control the RNG via MSR. Tread lightly and pay very close
* close attention to values written, as the reserved fields
* are documented to be "undefined and unpredictable"; but it
--
- Harald Welte <haraldwe...@viatech.com> http://linux.via.com.tw/
============================================================================
VIA Open Source Liaison
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