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>

1 files changed, 26 insertions, 1 deletions

diff --git a/arch/sparc/kernel/time_64.c b/arch/sparc/kernel/time_64.c
index a62758ce9e19..f584c53e769a 100644
--- 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 = {