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Diffstat (limited to 'arch/powerpc/platforms/powernv/rng.c')
-rw-r--r--arch/powerpc/platforms/powernv/rng.c45
1 files changed, 42 insertions, 3 deletions
diff --git a/arch/powerpc/platforms/powernv/rng.c b/arch/powerpc/platforms/powernv/rng.c
index 1a9d84371a4d..718f50ed22f1 100644
--- a/arch/powerpc/platforms/powernv/rng.c
+++ b/arch/powerpc/platforms/powernv/rng.c
@@ -16,11 +16,13 @@
#include <linux/slab.h>
#include <linux/smp.h>
#include <asm/archrandom.h>
+#include <asm/cputable.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/smp.h>
+#define DARN_ERR 0xFFFFFFFFFFFFFFFFul
struct powernv_rng {
void __iomem *regs;
@@ -67,6 +69,41 @@ int powernv_get_random_real_mode(unsigned long *v)
return 1;
}
+int powernv_get_random_darn(unsigned long *v)
+{
+ unsigned long val;
+
+ /* Using DARN with L=1 - 64-bit conditioned random number */
+ asm volatile(PPC_DARN(%0, 1) : "=r"(val));
+
+ if (val == DARN_ERR)
+ return 0;
+
+ *v = val;
+
+ return 1;
+}
+
+static int initialise_darn(void)
+{
+ unsigned long val;
+ int i;
+
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ return -ENODEV;
+
+ for (i = 0; i < 10; i++) {
+ if (powernv_get_random_darn(&val)) {
+ ppc_md.get_random_seed = powernv_get_random_darn;
+ return 0;
+ }
+ }
+
+ pr_warn("Unable to use DARN for get_random_seed()\n");
+
+ return -EIO;
+}
+
int powernv_get_random_long(unsigned long *v)
{
struct powernv_rng *rng;
@@ -88,7 +125,7 @@ static __init void rng_init_per_cpu(struct powernv_rng *rng,
chip_id = of_get_ibm_chip_id(dn);
if (chip_id == -1)
- pr_warn("No ibm,chip-id found for %s.\n", dn->full_name);
+ pr_warn("No ibm,chip-id found for %pOF.\n", dn);
for_each_possible_cpu(cpu) {
if (per_cpu(powernv_rng, cpu) == NULL ||
@@ -141,8 +178,8 @@ static __init int rng_init(void)
for_each_compatible_node(dn, NULL, "ibm,power-rng") {
rc = rng_create(dn);
if (rc) {
- pr_err("Failed creating rng for %s (%d).\n",
- dn->full_name, rc);
+ pr_err("Failed creating rng for %pOF (%d).\n",
+ dn, rc);
continue;
}
@@ -150,6 +187,8 @@ static __init int rng_init(void)
of_platform_device_create(dn, NULL, NULL);
}
+ initialise_darn();
+
return 0;
}
machine_subsys_initcall(powernv, rng_init);