[SPARC64]: Fetch bootup time of day from Hypervisor.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 50 insertions, 8 deletions

diff --git a/arch/sparc64/kernel/time.c b/arch/sparc64/kernel/time.c
index a22930d62adf..24681b9b4426 100644
--- a/arch/sparc64/kernel/time.c
+++ b/arch/sparc64/kernel/time.c
@@ -683,6 +683,48 @@ static void __init set_system_time(void)
         }
 }
 
+/* davem suggests we keep this within the 4M locked kernel image */
+static u32 starfire_get_time(void)
+{
+        static char obp_gettod[32];
+        static u32 unix_tod;
+
+        sprintf(obp_gettod, "h# %08x unix-gettod",
+                (unsigned int) (long) &unix_tod);
+        prom_feval(obp_gettod);
+
+        return unix_tod;
+}
+
+static u32 hypervisor_get_time(void)
+{
+        register unsigned long func asm("%o5");
+        register unsigned long arg0 asm("%o0");
+        register unsigned long arg1 asm("%o1");
+        int retries = 10000;
+
+retry:
+        func = HV_FAST_TOD_GET;
+        arg0 = 0;
+        arg1 = 0;
+        __asm__ __volatile__("ta        %6"
+                             : "=&r" (func), "=&r" (arg0), "=&r" (arg1)
+                             : "0" (func), "1" (arg0), "2" (arg1),
+                               "i" (HV_FAST_TRAP));
+        if (arg0 == HV_EOK)
+                return arg1;
+        if (arg0 == HV_EWOULDBLOCK) {
+                if (--retries > 0) {
+                        udelay(100);
+                        goto retry;
+                }
+                printk(KERN_WARNING "SUN4V: tod_get() timed out.\n");
+                return 0;
+        }
+        printk(KERN_WARNING "SUN4V: tod_get() not supported.\n");
+        return 0;
+}
+
 void __init clock_probe(void)
 {
         struct linux_prom_registers clk_reg[2];
@@ -702,14 +744,14 @@ void __init clock_probe(void)
 
 
         if (this_is_starfire) {
-                /* davem suggests we keep this within the 4M locked kernel image */
-                static char obp_gettod[256];
-                static u32 unix_tod;
-
-                sprintf(obp_gettod, "h# %08x unix-gettod",
-                        (unsigned int) (long) &unix_tod);
-                prom_feval(obp_gettod);
-                xtime.tv_sec = unix_tod;
+                xtime.tv_sec = starfire_get_time();
+                xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
+                set_normalized_timespec(&wall_to_monotonic,
+                                        -xtime.tv_sec, -xtime.tv_nsec);
+                return;
+        }
+        if (tlb_type == hypervisor) {
+                xtime.tv_sec = hypervisor_get_time();
                 xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
                 set_normalized_timespec(&wall_to_monotonic,
                                         -xtime.tv_sec, -xtime.tv_nsec);