MIPS: Unify checks for sibling CPUs

Up until now we have open-coded checks for whether CPUs are siblings,
with slight variations on whether we consider the package ID or not.

This will only get more complex when we introduce cluster support, so in
preparation for that this patch introduces a cpus_are_siblings()
function which can be used to check whether or not 2 CPUs are siblings
in a consistent manner.

By checking globalnumber with the VP ID masked out this also has the
neat side effect of being ready for multi-cluster systems already.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Acked-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17011/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/arch/mips/include/asm/cpu-info.h b/arch/mips/include/asm/cpu-info.h
index 9ae927282b12..0c61bdc82a53 100644
--- a/arch/mips/include/asm/cpu-info.h
+++ b/arch/mips/include/asm/cpu-info.h
@@ -158,6 +158,23 @@ static inline unsigned int cpu_vpe_id(struct cpuinfo_mips *cpuinfo)
 extern void cpu_set_core(struct cpuinfo_mips *cpuinfo, unsigned int core);
 extern void cpu_set_vpe_id(struct cpuinfo_mips *cpuinfo, unsigned int vpe);
 
+static inline bool cpus_are_siblings(int cpua, int cpub)
+{
+	struct cpuinfo_mips *infoa = &cpu_data[cpua];
+	struct cpuinfo_mips *infob = &cpu_data[cpub];
+	unsigned int gnuma, gnumb;
+
+	if (infoa->package != infob->package)
+		return false;
+
+	gnuma = infoa->globalnumber & ~MIPS_GLOBALNUMBER_VP;
+	gnumb = infob->globalnumber & ~MIPS_GLOBALNUMBER_VP;
+	if (gnuma != gnumb)
+		return false;
+
+	return true;
+}
+
 static inline unsigned long cpu_asid_inc(void)
 {
 	return 1 << CONFIG_MIPS_ASID_SHIFT;