From: Paul Burton <paulburton@xxxxxxxxxx>
Introduce support for multi-cluster GIC register access in
__gic_with_next_online_cpu(), and therefore in its user
for_each_online_cpu_gic(). 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@xxxxxxxxxx>
Signed-off-by: Chao-ying Fu <cfu@xxxxxxxxxxxx>
Signed-off-by: Dragan Mladjenovic <dragan.mladjenovic@xxxxxxxxxx>
Signed-off-by: Aleksandar Rikalo <aleksandar.rikalo@xxxxxxxxxx>
---
drivers/irqchip/irq-mips-gic.c | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
diff --git a/drivers/irqchip/irq-mips-gic.c b/drivers/irqchip/irq-mips-gic.c
index 9e7182150b5c..317ccc2593d1 100644
--- a/drivers/irqchip/irq-mips-gic.c
+++ b/drivers/irqchip/irq-mips-gic.c
@@ -70,6 +70,20 @@ 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);
@@ -80,10 +94,16 @@ 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;
}
@@ -105,6 +125,9 @@ static inline void __lockdep_assert_held(raw_spinlock_t *gic_lock)
*
* The caller must hold gic_lock throughout the loop, such that GIC_VL_OTHER
* cannot be clobbered.
+ *
+ * Please note that if you start a loop this way, it must be completed to the
+ * end, otherwise, GIC local register block will remain locked.
*/
#define for_each_online_cpu_gic(cpu, gic_lock) \
for (__lockdep_assert_held(gic_lock), \
--
2.25.1
