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MIPS: CPC: Avoid lock when MIPS CM >= 3 is present 

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>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/14219/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Matt Redfearn 2016-09-07 10:45:10 +01:00 committed by Ralf Baechle
parent 6b89d22e74
commit d621942048
1 changed files with 12 additions and 1 deletions
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13
arch/mips/kernel/mips-cpc.c
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@ -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();