diff options
Diffstat (limited to 'arch/powerpc/platforms/powernv/rng.c')
| -rw-r--r-- | arch/powerpc/platforms/powernv/rng.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powernv/rng.c b/arch/powerpc/platforms/powernv/rng.c index 1a9d84371a4d..c5ce3a8bd4c9 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; @@ -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); |