diff mbox series

[v10,04/13] iommu/arm-smmu-qcom: Add implementation for the adreno GPU SMMU

Message ID 20200720154047.3611092-5-jcrouse@codeaurora.org (mailing list archive)
State New, archived
Headers show
Series iommu/arm-smmu: Add Adreno SMMU specific implementation | expand

Commit Message

Jordan Crouse July 20, 2020, 3:40 p.m. UTC 
Add a special implementation for the SMMU attached to most Adreno GPU
target triggered from the qcom,adreno-smmu compatible string.

The new Adreno SMMU implementation will enable split pagetables
(TTBR1) for the domain attached to the GPU device (SID 0) and
hard code it context bank 0 so the GPU hardware can implement
per-instance pagetables.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
---

 drivers/iommu/arm-smmu-impl.c |  3 ++
 drivers/iommu/arm-smmu-qcom.c | 83 ++++++++++++++++++++++++++++++++++-
 drivers/iommu/arm-smmu.h      |  1 +
 3 files changed, 85 insertions(+), 2 deletions(-)

Comments

Bjorn Andersson July 27, 2020, 6:27 a.m. UTC | #1 
On Mon 20 Jul 08:40 PDT 2020, Jordan Crouse wrote:
> diff --git a/drivers/iommu/arm-smmu-qcom.c b/drivers/iommu/arm-smmu-qcom.c
[..]
> +static int qcom_adreno_smmu_alloc_context_bank(struct arm_smmu_domain *smmu_domain,
> +		struct device *dev, int start, int count)
> +{
> +	struct arm_smmu_device *smmu = smmu_domain->smmu;
> +
> +	/*
> +	 * Assign context bank 0 to the GPU device so the GPU hardware can
> +	 * switch pagetables
> +	 */
> +	if (qcom_adreno_smmu_is_gpu_device(dev)) {
> +		if (start > 0 || test_bit(0, smmu->context_map))
> +			return -ENOSPC;
> +
> +		set_bit(0, smmu->context_map);
> +		return 0;
> +	}
> +
> +	return __arm_smmu_alloc_bitmap(smmu->context_map, start, count);

If we end up here before the GPU device shows up this is going to
steal the first context bank, causing the subsequent allocation for the
GPU to always fail.

As such I think it would be appropriate for you to adjust "start" to
never be 0 here. And I think it would be appropriate to write this
function as:

	if (gpu) {
		start = 0;
		count = 1;
	} else {
		if (start == 0)
			start = 1;
	}

	return __arm_smmu_alloc_bitmap(smmu->context_map, start, count);

Regards,
Bjorn
Jordan Crouse July 27, 2020, 2:57 p.m. UTC | #2 
On Sun, Jul 26, 2020 at 11:27:03PM -0700, Bjorn Andersson wrote:
> On Mon 20 Jul 08:40 PDT 2020, Jordan Crouse wrote:
> > diff --git a/drivers/iommu/arm-smmu-qcom.c b/drivers/iommu/arm-smmu-qcom.c
> [..]
> > +static int qcom_adreno_smmu_alloc_context_bank(struct arm_smmu_domain *smmu_domain,
> > +		struct device *dev, int start, int count)
> > +{
> > +	struct arm_smmu_device *smmu = smmu_domain->smmu;
> > +
> > +	/*
> > +	 * Assign context bank 0 to the GPU device so the GPU hardware can
> > +	 * switch pagetables
> > +	 */
> > +	if (qcom_adreno_smmu_is_gpu_device(dev)) {
> > +		if (start > 0 || test_bit(0, smmu->context_map))
> > +			return -ENOSPC;
> > +
> > +		set_bit(0, smmu->context_map);
> > +		return 0;
> > +	}
> > +
> > +	return __arm_smmu_alloc_bitmap(smmu->context_map, start, count);
> 
> If we end up here before the GPU device shows up this is going to
> steal the first context bank, causing the subsequent allocation for the
> GPU to always fail.
> 
> As such I think it would be appropriate for you to adjust "start" to
> never be 0 here. And I think it would be appropriate to write this
> function as:
> 
> 	if (gpu) {
> 		start = 0;
> 		count = 1;
> 	} else {
> 		if (start == 0)
> 			start = 1;
> 	}
> 
> 	return __arm_smmu_alloc_bitmap(smmu->context_map, start, count);

Excellent suggestions.  Thanks.

Jordan

> Regards,
> Bjorn
diff mbox series

Patch

diff --git a/drivers/iommu/arm-smmu-impl.c b/drivers/iommu/arm-smmu-impl.c
index b71b14685cc9..3bb1ef4e85f7 100644
--- a/drivers/iommu/arm-smmu-impl.c
+++ b/drivers/iommu/arm-smmu-impl.c
@@ -176,5 +176,8 @@  struct arm_smmu_device *arm_smmu_impl_init(struct arm_smmu_device *smmu)
 	    of_device_is_compatible(np, "qcom,sc7180-smmu-500"))
 		return qcom_smmu_impl_init(smmu);
 
+	if (of_device_is_compatible(smmu->dev->of_node, "qcom,adreno-smmu"))
+		return qcom_adreno_smmu_impl_init(smmu);
+
 	return smmu;
 }
diff --git a/drivers/iommu/arm-smmu-qcom.c b/drivers/iommu/arm-smmu-qcom.c
index be4318044f96..b9a5c5369e86 100644
--- a/drivers/iommu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm-smmu-qcom.c
@@ -12,6 +12,67 @@  struct qcom_smmu {
 	struct arm_smmu_device smmu;
 };
 
+#define QCOM_ADRENO_SMMU_GPU_SID 0
+
+static bool qcom_adreno_smmu_is_gpu_device(struct device *dev)
+{
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+	struct arm_smmu_master_cfg *cfg = dev_iommu_priv_get(dev);
+	int idx, i;
+
+	/*
+	 * The GPU will always use SID 0 so that is a handy way to uniquely
+	 * identify it and configure it for per-instance pagetables
+	 */
+	for_each_cfg_sme(cfg, fwspec, i, idx) {
+		u16 sid = FIELD_GET(ARM_SMMU_SMR_ID, fwspec->ids[i]);
+
+		if (sid == QCOM_ADRENO_SMMU_GPU_SID)
+			return true;
+	}
+
+	return false;
+}
+
+static int qcom_adreno_smmu_alloc_context_bank(struct arm_smmu_domain *smmu_domain,
+		struct device *dev, int start, int count)
+{
+	struct arm_smmu_device *smmu = smmu_domain->smmu;
+
+	/*
+	 * Assign context bank 0 to the GPU device so the GPU hardware can
+	 * switch pagetables
+	 */
+	if (qcom_adreno_smmu_is_gpu_device(dev)) {
+		if (start > 0 || test_bit(0, smmu->context_map))
+			return -ENOSPC;
+
+		set_bit(0, smmu->context_map);
+		return 0;
+	}
+
+	return __arm_smmu_alloc_bitmap(smmu->context_map, start, count);
+}
+
+static int qcom_adreno_smmu_init_context(struct arm_smmu_domain *smmu_domain,
+		struct io_pgtable_cfg *pgtbl_cfg, struct device *dev)
+{
+	/* Only enable split pagetables for the GPU device (SID 0) */
+	if (!qcom_adreno_smmu_is_gpu_device(dev))
+		return 0;
+
+	/*
+	 * All targets that use the qcom,adreno-smmu compatible string *should*
+	 * be AARCH64 stage 1 but double check because the arm-smmu code assumes
+	 * that is the case when the TTBR1 quirk is enabled
+	 */
+	if ((smmu_domain->stage == ARM_SMMU_DOMAIN_S1) &&
+	    (smmu_domain->cfg.fmt == ARM_SMMU_CTX_FMT_AARCH64))
+		pgtbl_cfg->quirks |= IO_PGTABLE_QUIRK_ARM_TTBR1;
+
+	return 0;
+}
+
 static const struct of_device_id qcom_smmu_client_of_match[] __maybe_unused = {
 	{ .compatible = "qcom,adreno" },
 	{ .compatible = "qcom,mdp4" },
@@ -65,7 +126,15 @@  static const struct arm_smmu_impl qcom_smmu_impl = {
 	.reset = qcom_smmu500_reset,
 };
 
-struct arm_smmu_device *qcom_smmu_impl_init(struct arm_smmu_device *smmu)
+static const struct arm_smmu_impl qcom_adreno_smmu_impl = {
+	.init_context = qcom_adreno_smmu_init_context,
+	.def_domain_type = qcom_smmu_def_domain_type,
+	.reset = qcom_smmu500_reset,
+	.alloc_context_bank = qcom_adreno_smmu_alloc_context_bank,
+};
+
+static struct arm_smmu_device *qcom_smmu_create(struct arm_smmu_device *smmu,
+		const struct arm_smmu_impl *impl)
 {
 	struct qcom_smmu *qsmmu;
 
@@ -75,8 +144,18 @@  struct arm_smmu_device *qcom_smmu_impl_init(struct arm_smmu_device *smmu)
 
 	qsmmu->smmu = *smmu;
 
-	qsmmu->smmu.impl = &qcom_smmu_impl;
+	qsmmu->smmu.impl = impl;
 	devm_kfree(smmu->dev, smmu);
 
 	return &qsmmu->smmu;
 }
+
+struct arm_smmu_device *qcom_smmu_impl_init(struct arm_smmu_device *smmu)
+{
+	return qcom_smmu_create(smmu, &qcom_smmu_impl);
+}
+
+struct arm_smmu_device *qcom_adreno_smmu_impl_init(struct arm_smmu_device *smmu)
+{
+	return qcom_smmu_create(smmu, &qcom_adreno_smmu_impl);
+}
diff --git a/drivers/iommu/arm-smmu.h b/drivers/iommu/arm-smmu.h
index d10d745a0290..9f81c1fffe1e 100644
--- a/drivers/iommu/arm-smmu.h
+++ b/drivers/iommu/arm-smmu.h
@@ -491,6 +491,7 @@  static inline void arm_smmu_writeq(struct arm_smmu_device *smmu, int page,
 
 struct arm_smmu_device *arm_smmu_impl_init(struct arm_smmu_device *smmu);
 struct arm_smmu_device *qcom_smmu_impl_init(struct arm_smmu_device *smmu);
+struct arm_smmu_device *qcom_adreno_smmu_impl_init(struct arm_smmu_device *smmu);
 
 int arm_mmu500_reset(struct arm_smmu_device *smmu);