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From: Tomasz Jeznach <tjeznach@rivosinc.com>
To: Joerg Roedel <joro@8bytes.org>,
	Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Anup Patel <apatel@ventanamicro.com>,
	Sunil V L <sunilvl@ventanamicro.com>,
	Nick Kossifidis <mick@ics.forth.gr>,
	Sebastien Boeuf <seb@rivosinc.com>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	devicetree@vger.kernel.org,
	iommu@lists.linux.dev,
	linux-riscv@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	linux@rivosinc.com,
	Tomasz Jeznach <tjeznach@rivosinc.com>
Subject: [PATCH v2 4/7] iommu/riscv: Enable IOMMU registration and device probe.
Date: Thu, 18 Apr 2024 09:32:22 -0700
Message-Id: <c681ad581ddf644a288cac44ed4f7fdfd1acae0a.1713456598.git.tjeznach@rivosinc.com>
In-Reply-To: <cover.1713456597.git.tjeznach@rivosinc.com>
References: <cover.1713456597.git.tjeznach@rivosinc.com>
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Advertise IOMMU device and its core API.
Only minimal implementation for single identity domain type, without
per-group domain protection.

Signed-off-by: Tomasz Jeznach <tjeznach@rivosinc.com>
---
 drivers/iommu/riscv/iommu.c | 69 +++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

diff --git a/drivers/iommu/riscv/iommu.c b/drivers/iommu/riscv/iommu.c
index af68c89200a9..d38317cb2493 100644
--- a/drivers/iommu/riscv/iommu.c
+++ b/drivers/iommu/riscv/iommu.c
@@ -18,6 +18,7 @@
 #include <linux/iommu.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/pci.h>
 
 #include "iommu-bits.h"
 #include "iommu.h"
@@ -30,6 +31,67 @@ MODULE_LICENSE("GPL");
 /* Timeouts in [us] */
 #define RISCV_IOMMU_DDTP_TIMEOUT	50000
 
+static int riscv_iommu_attach_identity_domain(struct iommu_domain *domain,
+					      struct device *dev)
+{
+	/* Global pass-through already enabled, do nothing for now. */
+	return 0;
+}
+
+static struct iommu_domain riscv_iommu_identity_domain = {
+	.type = IOMMU_DOMAIN_IDENTITY,
+	.ops = &(const struct iommu_domain_ops) {
+		.attach_dev = riscv_iommu_attach_identity_domain,
+	}
+};
+
+static int riscv_iommu_device_domain_type(struct device *dev)
+{
+	return IOMMU_DOMAIN_IDENTITY;
+}
+
+static struct iommu_group *riscv_iommu_device_group(struct device *dev)
+{
+	if (dev_is_pci(dev))
+		return pci_device_group(dev);
+	return generic_device_group(dev);
+}
+
+static int riscv_iommu_of_xlate(struct device *dev, const struct of_phandle_args *args)
+{
+	return iommu_fwspec_add_ids(dev, args->args, 1);
+}
+
+static struct iommu_device *riscv_iommu_probe_device(struct device *dev)
+{
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+	struct riscv_iommu_device *iommu;
+
+	if (!fwspec->iommu_fwnode->dev || !fwspec->num_ids)
+		return ERR_PTR(-ENODEV);
+
+	iommu = dev_get_drvdata(fwspec->iommu_fwnode->dev);
+	if (!iommu)
+		return ERR_PTR(-ENODEV);
+
+	return &iommu->iommu;
+}
+
+static void riscv_iommu_probe_finalize(struct device *dev)
+{
+	iommu_setup_dma_ops(dev, 0, U64_MAX);
+}
+
+static const struct iommu_ops riscv_iommu_ops = {
+	.owner = THIS_MODULE,
+	.of_xlate = riscv_iommu_of_xlate,
+	.identity_domain = &riscv_iommu_identity_domain,
+	.def_domain_type = riscv_iommu_device_domain_type,
+	.device_group = riscv_iommu_device_group,
+	.probe_device = riscv_iommu_probe_device,
+	.probe_finalize = riscv_iommu_probe_finalize,
+};
+
 static int riscv_iommu_init_check(struct riscv_iommu_device *iommu)
 {
 	u64 ddtp;
@@ -60,6 +122,7 @@ static int riscv_iommu_init_check(struct riscv_iommu_device *iommu)
 
 void riscv_iommu_remove(struct riscv_iommu_device *iommu)
 {
+	iommu_device_unregister(&iommu->iommu);
 	iommu_device_sysfs_remove(&iommu->iommu);
 }
 
@@ -82,8 +145,14 @@ int riscv_iommu_init(struct riscv_iommu_device *iommu)
 	if (WARN(rc, "cannot register sysfs interface\n"))
 		goto err_sysfs;
 
+	rc = iommu_device_register(&iommu->iommu, &riscv_iommu_ops, iommu->dev);
+	if (WARN(rc, "cannot register iommu interface\n"))
+		goto err_iommu;
+
 	return 0;
 
+err_iommu:
+	iommu_device_sysfs_remove(&iommu->iommu);
 err_sysfs:
 	return rc;
 }
-- 
2.34.1