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Commit cf03a5c0 authored by Prakash Gupta's avatar Prakash Gupta
Browse files

iommu/arm-smmu: reduce tlb sync poll retry latency 



Limit tlb sync poll retry latency to a upper limit. This reduces the
response time of tlb sync completion.

Change-Id: I7b92e216c17f5942ad01a9e9f24eff88f7608388
Signed-off-by: default avatarPrakash Gupta <guptap@codeaurora.org>
parent 020668f2

drivers/iommu/arm-smmu.c

+10 −9
Original line number Diff line number Diff line
@@ -86,7 +86,7 @@ 
#define ARM_MMU500_ACR_SMTNMB_TLBEN	(1 << 8)



#define TLB_LOOP_TIMEOUT		500000	/* 500ms */

#define TLB_SPIN_COUNT			10

#define TLB_LOOP_INC_MAX		1000      /*1ms*/



#define ARM_SMMU_IMPL_DEF0(smmu) \

	((smmu)->base + (2 * (1 << (smmu)->pgshift)))
@@ -1280,16 +1280,17 @@ static void __arm_smmu_tlb_sync_timeout(struct arm_smmu_device *smmu) 
static int __arm_smmu_tlb_sync(struct arm_smmu_device *smmu,

			void __iomem *sync, void __iomem *status)

{

	unsigned int spin_cnt, delay;

	unsigned int inc, delay;



	writel_relaxed(QCOM_DUMMY_VAL, sync);

	for (delay = 1; delay < TLB_LOOP_TIMEOUT; delay *= 2) {

		for (spin_cnt = TLB_SPIN_COUNT; spin_cnt > 0; spin_cnt--) {

	for (delay = 1, inc = 1; delay < TLB_LOOP_TIMEOUT; delay += inc) {

		if (!(readl_relaxed(status) & sTLBGSTATUS_GSACTIVE))

			return 0;



		cpu_relax();

		}

		udelay(delay);

		udelay(inc);

		if (inc < TLB_LOOP_INC_MAX)

			inc *= 2;

	}

	trace_tlbsync_timeout(smmu->dev, 0);

	__arm_smmu_tlb_sync_timeout(smmu);