irqchip/mips-gic: Support multi-cluster in for_each_online_cpu_gic()

Use CM's GCR_CL_REDIRECT register to access registers in remote clusters,
so that users of gic_with_each_online_cpu() gains support for multi-cluster
without further changes.

Signed-off-by: Paul Burton <[email protected]>
Signed-off-by: Chao-ying Fu <[email protected]>
Signed-off-by: Dragan Mladjenovic <[email protected]>
Signed-off-by: Aleksandar Rikalo <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Serge Semin <[email protected]>
Tested-by: Gregory CLEMENT <[email protected]>
Link: https://lore.kernel.org/all/[email protected]

Author: paulburton

drivers/irqchip/irq-mips-gic.c

@@ -88,6 +88,12 @@ static int __gic_with_next_online_cpu(int prev)
 	return cpu;
 }
 
+static inline void gic_unlock_cluster(void)
+{
+	if (mips_cps_multicluster_cpus())
+		mips_cm_unlock_other();
+}
+
 /**
  * for_each_online_cpu_gic() - Iterate over online CPUs, access local registers
  * @cpu: An integer variable to hold the current CPU number
@@ -102,6 +108,7 @@ static int __gic_with_next_online_cpu(int prev)
 	guard(raw_spinlock_irqsave)(gic_lock);		\
 	for ((cpu) = __gic_with_next_online_cpu(-1);	\
 	     (cpu) < nr_cpu_ids;			\
+	     gic_unlock_cluster(),			\
 	     (cpu) = __gic_with_next_online_cpu(cpu))
 
 static void gic_clear_pcpu_masks(unsigned int intr)