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Subject[PATCH 02/10] MIPS: CPC: Avoid lock when MIPS CM >= 3 is present
Date
MIPS CM version 3 removed the CPC_CL_OTHER register and instead the
CM_CL_OTHER register is used to redirect the CPC_OTHER region. As such,
we should not write the unimplmented register and can avoid the
spinlock as well.
These lock functions should aleady be called within the context of a
mips_cm_{lock,unlock}_other pair ensuring the correct CPC_OTHER region
will be accessed.

Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
---

arch/mips/kernel/mips-cpc.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/mips/kernel/mips-cpc.c b/arch/mips/kernel/mips-cpc.c
index 0e337f55ac60..2a45867d3b4f 100644
--- a/arch/mips/kernel/mips-cpc.c
+++ b/arch/mips/kernel/mips-cpc.c
@@ -71,6 +71,11 @@ int mips_cpc_probe(void)
void mips_cpc_lock_other(unsigned int core)
{
unsigned int curr_core;
+
+ if (mips_cm_revision() >= CM_REV_CM3)
+ /* Systems with CM >= 3 lock the CPC via mips_cm_lock_other */
+ return;
+
preempt_disable();
curr_core = current_cpu_data.core;
spin_lock_irqsave(&per_cpu(cpc_core_lock, curr_core),
@@ -86,7 +91,13 @@ void mips_cpc_lock_other(unsigned int core)

void mips_cpc_unlock_other(void)
{
- unsigned int curr_core = current_cpu_data.core;
+ unsigned int curr_core;
+
+ if (mips_cm_revision() >= CM_REV_CM3)
+ /* Systems with CM >= 3 lock the CPC via mips_cm_lock_other */
+ return;
+
+ curr_core = current_cpu_data.core;
spin_unlock_irqrestore(&per_cpu(cpc_core_lock, curr_core),
per_cpu(cpc_core_lock_flags, curr_core));
preempt_enable();
--
2.7.4
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