1 files changed, 63 insertions, 0 deletions

diff --git a/arch/ppc64/kernel/time.c b/arch/ppc64/kernel/time.c
index 33364a7d2cd2..2348a75e050d 100644
--- a/arch/ppc64/kernel/time.c
+++ b/arch/ppc64/kernel/time.c
@@ -107,6 +107,9 @@ void ppc_adjtimex(void);
 
 static unsigned adjusting_time = 0;
 
+unsigned long ppc_proc_freq;
+unsigned long ppc_tb_freq;
+
 static __inline__ void timer_check_rtc(void)
 {
         /*
@@ -472,6 +475,66 @@ int do_settimeofday(struct timespec *tv)
 
 EXPORT_SYMBOL(do_settimeofday);
 
+#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_MAPLE) || defined(CONFIG_PPC_BPA)
+void __init generic_calibrate_decr(void)
+{
+        struct device_node *cpu;
+        struct div_result divres;
+        unsigned int *fp;
+        int node_found;
+
+        /*
+         * The cpu node should have a timebase-frequency property
+         * to tell us the rate at which the decrementer counts.
+         */
+        cpu = of_find_node_by_type(NULL, "cpu");
+
+        ppc_tb_freq = DEFAULT_TB_FREQ;          /* hardcoded default */
+        node_found = 0;
+        if (cpu != 0) {
+                fp = (unsigned int *)get_property(cpu, "timebase-frequency",
+                                                  NULL);
+                if (fp != 0) {
+                        node_found = 1;
+                        ppc_tb_freq = *fp;
+                }
+        }
+        if (!node_found)
+                printk(KERN_ERR "WARNING: Estimating decrementer frequency "
+                                "(not found)\n");
+
+        ppc_proc_freq = DEFAULT_PROC_FREQ;
+        node_found = 0;
+        if (cpu != 0) {
+                fp = (unsigned int *)get_property(cpu, "clock-frequency",
+                                                  NULL);
+                if (fp != 0) {
+                        node_found = 1;
+                        ppc_proc_freq = *fp;
+                }
+        }
+        if (!node_found)
+                printk(KERN_ERR "WARNING: Estimating processor frequency "
+                                "(not found)\n");
+
+        of_node_put(cpu);
+
+        printk(KERN_INFO "time_init: decrementer frequency = %lu.%.6lu MHz\n",
+               ppc_tb_freq/1000000, ppc_tb_freq%1000000);
+        printk(KERN_INFO "time_init: processor frequency   = %lu.%.6lu MHz\n",
+               ppc_proc_freq/1000000, ppc_proc_freq%1000000);
+
+        tb_ticks_per_jiffy = ppc_tb_freq / HZ;
+        tb_ticks_per_sec = tb_ticks_per_jiffy * HZ;
+        tb_ticks_per_usec = ppc_tb_freq / 1000000;
+        tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000);
+        div128_by_32(1024*1024, 0, tb_ticks_per_sec, &divres);
+        tb_to_xs = divres.result_low;
+
+        setup_default_decr();
+}
+#endif
+
 void __init time_init(void)
 {
         /* This function is only called on the boot processor */