From d6219420480b75258b93583caa3885fb80d83313 Mon Sep 17 00:00:00 2001 From: Matt Redfearn Date: Wed, 7 Sep 2016 10:45:10 +0100 Subject: [PATCH] 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 Reviewed-by: Paul Burton 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 --- 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 0e337f5..2a45867 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