[PATCH v12 08/10] iommu/arm-smmu-v3: Add struct arm_smmu_impl_ops

[Nicolin Chen <nicolinc@nvidia.com>]

From: Jason Gunthorpe <jgg@nvidia.com>

NVIDIA Tegra241 implemented SMMU in a slightly different way that supports
a CMDQV extension feature as a secondary CMDQ for virtualization cases.

Mimicing the arm-smmu (v2) driver, introduce a struct arm_smmu_impl_ops to
accommodate impl routines.

Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 51 ++++++++++++++++++++-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |  9 ++++
 2 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 6df3cb0bc406..2159455cd781 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -338,7 +338,12 @@ static int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent)
 
 static struct arm_smmu_cmdq *arm_smmu_get_cmdq(struct arm_smmu_device *smmu)
 {
-	return &smmu->cmdq;
+	struct arm_smmu_cmdq *cmdq = NULL;
+
+	if (smmu->impl_ops && smmu->impl_ops->get_secondary_cmdq)
+		cmdq = smmu->impl_ops->get_secondary_cmdq(smmu);
+
+	return cmdq ?: &smmu->cmdq;
 }
 
 static bool arm_smmu_cmdq_needs_busy_polling(struct arm_smmu_device *smmu,
@@ -4044,6 +4049,14 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu)
 		return ret;
 	}
 
+	if (smmu->impl_ops && smmu->impl_ops->device_reset) {
+		ret = smmu->impl_ops->device_reset(smmu);
+		if (ret) {
+			dev_err(smmu->dev, "failed to reset impl\n");
+			return ret;
+		}
+	}
+
 	return 0;
 }
 
@@ -4450,6 +4463,38 @@ static void arm_smmu_rmr_install_bypass_ste(struct arm_smmu_device *smmu)
 	iort_put_rmr_sids(dev_fwnode(smmu->dev), &rmr_list);
 }
 
+static void arm_smmu_impl_remove(void *data)
+{
+	struct arm_smmu_device *smmu = data;
+
+	if (smmu->impl_ops && smmu->impl_ops->device_remove)
+		smmu->impl_ops->device_remove(smmu);
+}
+
+/*
+ * Probe all the compiled in implementations. Each one checks to see if it
+ * matches this HW and if so returns a devm_krealloc'd arm_smmu_device which
+ * replaces the callers. Otherwise the original is returned or ERR_PTR.
+ */
+static struct arm_smmu_device *arm_smmu_impl_probe(struct arm_smmu_device *smmu)
+{
+	struct arm_smmu_device *new_smmu = ERR_PTR(-ENODEV);
+	int ret;
+
+	/* Add impl probe */
+
+	if (new_smmu == ERR_PTR(-ENODEV))
+		return smmu;
+	if (IS_ERR(new_smmu))
+		return new_smmu;
+
+	ret = devm_add_action_or_reset(new_smmu->dev, arm_smmu_impl_remove,
+				       new_smmu);
+	if (ret)
+		return ERR_PTR(ret);
+	return new_smmu;
+}
+
 static int arm_smmu_device_probe(struct platform_device *pdev)
 {
 	int irq, ret;
@@ -4471,6 +4516,10 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	smmu = arm_smmu_impl_probe(smmu);
+	if (IS_ERR(smmu))
+		return PTR_ERR(smmu);
+
 	/* Base address */
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index 9f5d156b73af..475517729307 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -15,6 +15,7 @@
 #include <linux/sizes.h>
 
 struct acpi_iort_node;
+struct arm_smmu_device;
 
 /* MMIO registers */
 #define ARM_SMMU_IDR0			0x0
@@ -629,9 +630,17 @@ struct arm_smmu_strtab_cfg {
 	u32				strtab_base_cfg;
 };
 
+struct arm_smmu_impl_ops {
+	int (*device_reset)(struct arm_smmu_device *smmu);
+	void (*device_remove)(struct arm_smmu_device *smmu);
+	struct arm_smmu_cmdq *(*get_secondary_cmdq)(struct arm_smmu_device *smmu);
+};
+
 /* An SMMUv3 instance */
 struct arm_smmu_device {
 	struct device			*dev;
+	const struct arm_smmu_impl_ops	*impl_ops;
+
 	void __iomem			*base;
 	void __iomem			*page1;
 
-- 
2.43.0