linux-kernel - [PATCH] iommu/arm-smmu: Use context bank TLBSTATUS registers

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Date:   Mon, 22 May 2017 14:25:28 +0530
From:   vjitta@...eaurora.org
To:     will.deacon@....com, robin.murphy@....com, joro@...tes.org
Cc:     iommu@...ts.linux-foundation.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        shashim@...eaurora.org, guptap@...eaurora.org,
        Vijayanand Jitta <vjitta@...eaurora.org>
Subject: [PATCH] iommu/arm-smmu: Use context bank TLBSTATUS registers

From: Vijayanand Jitta <vjitta@...eaurora.org>

There are TLBSTATUS registers in SMMU global register space as well as
context bank register space.  Currently we're polling the global
TLBSTATUS registers after TLB invalidation, even when using the TLB
invalidation registers from context bank address space.  This violates
the usage model described in the ARM SMMU spec.  Fix this by polling
context bank TLBSTATUS registers for context bank TLB operations, and
global TLBSTATUS registers for global TLB operations.

Signed-off-by: Vijayanand Jitta <vjitta@...eaurora.org>
---
 drivers/iommu/arm-smmu.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 7cecc37..8dc6da9 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -233,6 +233,9 @@ enum arm_smmu_s2cr_privcfg {
 #define ARM_SMMU_CB_S1_TLBIVAL		0x620
 #define ARM_SMMU_CB_S2_TLBIIPAS2	0x630
 #define ARM_SMMU_CB_S2_TLBIIPAS2L	0x638
+#define ARM_SMMU_CB_TLBSYNC		0x7f0
+#define ARM_SMMU_CB_TLBSTATUS		0x7f4
+#define TLBSTATUS_SACTIVE		(1 << 0)
 #define ARM_SMMU_CB_ATS1PR		0x800
 #define ARM_SMMU_CB_ATSR		0x8f0
 
@@ -580,6 +583,19 @@ static void __arm_smmu_free_bitmap(unsigned long *map, int idx)
 }
 
 /* Wait for any pending TLB invalidations to complete */
+static void arm_smmu_tlb_sync_cb(struct arm_smmu_device *smmu,
+				int cbndx)
+{
+	void __iomem *base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, cbndx);
+	u32 val;
+
+	writel_relaxed(0, base + ARM_SMMU_CB_TLBSYNC);
+	if (readl_poll_timeout_atomic(base + ARM_SMMU_CB_TLBSTATUS, val,
+				      !(val & TLBSTATUS_SACTIVE),
+				      0, TLB_LOOP_TIMEOUT))
+		dev_err(smmu->dev, "TLBSYNC timeout!\n");
+}
+
 static void __arm_smmu_tlb_sync(struct arm_smmu_device *smmu)
 {
 	int count = 0;
@@ -601,7 +617,7 @@ static void __arm_smmu_tlb_sync(struct arm_smmu_device *smmu)
 static void arm_smmu_tlb_sync(void *cookie)
 {
 	struct arm_smmu_domain *smmu_domain = cookie;
-	__arm_smmu_tlb_sync(smmu_domain->smmu);
+	arm_smmu_tlb_sync_cb(smmu_domain->smmu, smmu_domain->cfg.cbndx);
 }
 
 static void arm_smmu_tlb_inv_context(void *cookie)
@@ -616,13 +632,13 @@ static void arm_smmu_tlb_inv_context(void *cookie)
 		base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, cfg->cbndx);
 		writel_relaxed(ARM_SMMU_CB_ASID(smmu, cfg),
 			       base + ARM_SMMU_CB_S1_TLBIASID);
+		arm_smmu_tlb_sync_cb(smmu, cfg->cbndx);
 	} else {
 		base = ARM_SMMU_GR0(smmu);
 		writel_relaxed(ARM_SMMU_CB_VMID(smmu, cfg),
 			       base + ARM_SMMU_GR0_TLBIVMID);
+		__arm_smmu_tlb_sync(smmu);
 	}
-
-	__arm_smmu_tlb_sync(smmu);
 }
 
 static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size,
-- 
1.9.1