sparc64: broken %tick frequency on spitfire cpus

After early boot time stamps project the %tick frequency is detected
incorrectly on spittfire cpus.

We must use cpuid of boot cpu to find corresponding cpu node in OpenBoot,
and extract clock-frequency property from there.

Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc/kernel/time_64.c b/arch/sparc/kernel/time_64.c
index a62758ce9e19ad8018d64505da2880efba17ad21..f584c53e769a6e898f436c94eb48c8283d43e161 100644 (file)
--- a/arch/sparc/kernel/time_64.c
+++ b/arch/sparc/kernel/time_64.c
@@ -162,9 +162,34 @@ static unsigned long tick_add_tick(unsigned long adj)
        return new_tick;
 }
 
+/* Searches for cpu clock frequency with given cpuid in OpenBoot tree */
+static unsigned long cpuid_to_freq(phandle node, int cpuid)
+{
+       bool is_cpu_node = false;
+       unsigned long freq = 0;
+       char type[128];
+
+       if (!node)
+               return freq;
+
+       if (prom_getproperty(node, "device_type", type, sizeof(type)) != -1)
+               is_cpu_node = (strcmp(type, "cpu") == 0);
+
+       /* try upa-portis then cpuid to get cpuid, see prom_64.c */
+       if (is_cpu_node && (prom_getint(node, "upa-portis") == cpuid ||
+                           prom_getint(node, "cpuid") == cpuid))
+               freq = prom_getintdefault(node, "clock-frequency", 0);
+       if (!freq)
+               freq = cpuid_to_freq(prom_getchild(node), cpuid);
+       if (!freq)
+               freq = cpuid_to_freq(prom_getsibling(node), cpuid);
+
+       return freq;
+}
+
 static unsigned long tick_get_frequency(void)
 {
-       return local_cpu_data().clock_tick;
+       return cpuid_to_freq(prom_root_node, hard_smp_processor_id());
 }
 
 static struct sparc64_tick_ops tick_operations __cacheline_aligned = {