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Commit a91e1462 authored by Prakash Gupta's avatar Prakash Gupta Committed by Chris Goldsworthy
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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>
Signed-off-by: default avatarChris Goldsworthy <cgoldswo@codeaurora.org>
parent 77a29a8c

drivers/iommu/arm-smmu.c

+11 −10
Original line number Diff line number Diff line
@@ -66,7 +66,7 @@ 
#define ARM_MMU500_ACR_CACHE_LOCK	(1 << 26)



#define TLB_LOOP_TIMEOUT		500000	/* 500ms */

#define TLB_SPIN_COUNT			10

#define TLB_LOOP_INC_MAX		1000      /*1ms*/



#define ARM_SMMU_IMPL_DEF1(smmu) \

	((smmu)->base + (6 * (1 << (smmu)->pgshift)))
@@ -886,19 +886,20 @@ static void arm_smmu_domain_power_off(struct iommu_domain *domain, 
static int __arm_smmu_tlb_sync(struct arm_smmu_device *smmu, int page,

				int sync, int status)

{

	unsigned int spin_cnt, delay;

	unsigned int inc, delay;

	u32 sync_inv_ack, tbu_pwr_status = -EINVAL, sync_inv_progress = -EINVAL;

	u32 reg;



	arm_smmu_writel(smmu, page, sync, QCOM_DUMMY_VAL);

	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) {

		reg = arm_smmu_readl(smmu, page, status);

		if (!(reg & sTLBGSTATUS_GSACTIVE))

			return 0;



		cpu_relax();

		}

		udelay(delay);

		udelay(inc);

		if (inc < TLB_LOOP_INC_MAX)

			inc *= 2;

	}



	sync_inv_ack = arm_smmu_readl(smmu,