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Subject[PATCH v2 04/12] irqchip: mips-gic: Support multi-cluster in gic_with_each_online_cpu()
Date
From: Paul Burton <paulburton@kernel.org>

Introduce support for multi-cluster GIC register access in
__gic_with_next_online_cpu(), and therefore in its user
gic_with_each_online_cpu(). We access registers in remote clusters using
the CM's GCR_CL_REDIRECT register, and so here we delegate to
mips_cm_lock_other() in order to configure this access.

With this done, users of gic_with_each_online_cpu() gain support for
multi-cluster with no further changes.

Signed-off-by: Paul Burton <paulburton@kernel.org>
Signed-off-by: Chao-ying Fu <cfu@wavecomp.com>
Signed-off-by: Dragan Mladjenovic <dragan.mladjenovic@syrmia.com>

diff --git a/drivers/irqchip/irq-mips-gic.c b/drivers/irqchip/irq-mips-gic.c
index 4872bebe24cf..89a3c6d04e09 100644
--- a/drivers/irqchip/irq-mips-gic.c
+++ b/drivers/irqchip/irq-mips-gic.c
@@ -69,6 +69,20 @@ static int __gic_with_next_online_cpu(int prev)
{
unsigned int cpu;

+ /*
+ * Unlock access to the previous CPU's GIC local register block.
+ *
+ * Delegate to the CM locking code in the multi-cluster case, since
+ * other clusters can only be accessed using GCR_CL_REDIRECT.
+ *
+ * In the single cluster case we don't need to do anything; the caller
+ * is responsible for maintaining gic_lock & nothing should be
+ * expecting any particular value of GIC_VL_OTHER so we can leave it
+ * as-is.
+ */
+ if ((prev != -1) && mips_cps_multicluster_cpus())
+ mips_cm_unlock_other();
+
/* Discover the next online CPU */
cpu = cpumask_next(prev, cpu_online_mask);

@@ -79,10 +93,16 @@ static int __gic_with_next_online_cpu(int prev)
/*
* Lock access to the next CPU's GIC local register block.
*
+ * Delegate to the CM locking code in the multi-cluster case, since
+ * other clusters can only be accessed using GCR_CL_REDIRECT.
+ *
* In the single cluster case we simply set GIC_VL_OTHER. The caller
* holds gic_lock so nothing can clobber the value we write.
*/
- write_gic_vl_other(mips_cm_vp_id(cpu));
+ if (mips_cps_multicluster_cpus())
+ mips_cm_lock_other_cpu(cpu, CM_GCR_Cx_OTHER_BLOCK_LOCAL);
+ else
+ write_gic_vl_other(mips_cm_vp_id(cpu));

return cpu;
}
--
2.17.1
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