[PATCH v2 1/3] iommu/arm-smmu: introduction of ACTLR for custom prefetcher settings

[Bibek Kumar Patro]

Currently in Qualcomm  SoCs the default prefetch is set to 1 which allows
the TLB to fetch just the next page table. MMU-500 features ACTLR
register which is implementation defined and is used for Qualcomm SoCs
to have a prefetch setting of 1/3/7/15 enabling TLB to prefetch
the next set of page tables accordingly allowing for faster translations.

ACTLR value is unique for each SMR (Stream matching register) and stored
in a pre-populated table. This value is set to the register during
context bank initialisation.

Signed-off-by: Bibek Kumar Patro <quic_bibekkum at quicinc.com>
---
 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 41 ++++++++++++++++++++++
 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.h |  2 ++
 drivers/iommu/arm/arm-smmu/arm-smmu.c      |  5 +--
 drivers/iommu/arm/arm-smmu/arm-smmu.h      |  5 +++
 4 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index 549ae4dba3a6..578c662c7c30 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -14,6 +14,17 @@

 #define QCOM_DUMMY_VAL	-1

+struct actlr_config {
+	const struct actlr_data *adata;
+	size_t size;
+};
+
+struct actlr_data {
+	u16 sid;
+	u16 mask;
+	u32 actlr;
+};
+
 static struct qcom_smmu *to_qcom_smmu(struct arm_smmu_device *smmu)
 {
 	return container_of(smmu, struct qcom_smmu, smmu);
@@ -261,9 +272,36 @@ static const struct of_device_id qcom_smmu_client_of_match[] __maybe_unused = {
 	{ }
 };

+static void arm_smmu_set_actlr(struct arm_smmu_device *smmu, int idx,
+		const struct actlr_config *actlrcfg)
+{
+	struct arm_smmu_smr *smr = smmu->smrs;
+	int i;
+	u16 id;
+	u16 mask;
+
+	for (i = 0; i < actlrcfg->size; ++i) {
+		id = actlrcfg->adata[i].sid;
+		mask = actlrcfg->adata[i].mask;
+		if (!smr_is_subset(*smr, id, mask))
+			arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_ACTLR,
+					actlrcfg->adata[i].actlr);
+	}
+}
+
 static int qcom_smmu_init_context(struct arm_smmu_domain *smmu_domain,
 		struct io_pgtable_cfg *pgtbl_cfg, struct device *dev)
 {
+	struct arm_smmu_device *smmu = smmu_domain->smmu;
+	struct qcom_smmu *qsmmu = to_qcom_smmu(smmu);
+	const struct actlr_config *actlrcfg;
+	int idx = smmu_domain->cfg.cbndx;
+
+	if (qsmmu->actlrcfg) {
+		actlrcfg = qsmmu->actlrcfg;
+		arm_smmu_set_actlr(smmu, idx, actlrcfg);
+	}
+
 	smmu_domain->cfg.flush_walk_prefer_tlbiasid = true;

 	return 0;
@@ -467,6 +505,9 @@ static struct arm_smmu_device *qcom_smmu_create(struct arm_smmu_device *smmu,
 	qsmmu->smmu.impl = impl;
 	qsmmu->cfg = data->cfg;

+	if (data->actlrcfg && (data->actlrcfg->size))
+		qsmmu->actlrcfg = data->actlrcfg;
+
 	return &qsmmu->smmu;
 }

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.h b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.h
index 593910567b88..4b6862715070 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.h
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.h
@@ -9,6 +9,7 @@
 struct qcom_smmu {
 	struct arm_smmu_device smmu;
 	const struct qcom_smmu_config *cfg;
+	const struct actlr_config *actlrcfg;
 	bool bypass_quirk;
 	u8 bypass_cbndx;
 	u32 stall_enabled;
@@ -25,6 +26,7 @@ struct qcom_smmu_config {
 };

 struct qcom_smmu_match_data {
+	const struct actlr_config *actlrcfg;
 	const struct qcom_smmu_config *cfg;
 	const struct arm_smmu_impl *impl;
 	const struct arm_smmu_impl *adreno_impl;
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index d6d1a2a55cc0..8e4faf015286 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -990,9 +990,10 @@ static int arm_smmu_find_sme(struct arm_smmu_device *smmu, u16 id, u16 mask)
 		 * expect simply identical entries for this case, but there's
 		 * no harm in accommodating the generalisation.
 		 */
-		if ((mask & smrs[i].mask) == mask &&
-		    !((id ^ smrs[i].id) & ~smrs[i].mask))
+
+		if (smr_is_subset(smrs[i], id, mask))
 			return i;
+
 		/*
 		 * If the new entry has any other overlap with an existing one,
 		 * though, then there always exists at least one stream ID
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h b/drivers/iommu/arm/arm-smmu/arm-smmu.h
index 703fd5817ec1..b1638bbc41d4 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.h
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h
@@ -501,6 +501,11 @@ static inline void arm_smmu_writeq(struct arm_smmu_device *smmu, int page,
 		writeq_relaxed(val, arm_smmu_page(smmu, page) + offset);
 }

+static inline bool smr_is_subset(struct arm_smmu_smr smrs, u16 id, u16 mask)
+{
+	return (mask & smrs.mask) == mask && !((id ^ smrs.id) & ~smrs.mask);
+}
+
 #define ARM_SMMU_GR0		0
 #define ARM_SMMU_GR1		1
 #define ARM_SMMU_CB(s, n)	((s)->numpage + (n))
--
2.17.1