[PATCH v6 4/7] iommu/riscv: Enable IOMMU registration and device probe.

Tomasz Jeznach
2024-05-24T19:35:23Z

Advertise IOMMU device and its core API.
Only minimal implementation for single identity domain type, without
per-group domain protection.

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Tomasz Jeznach <tjeznach@rivosinc.com>
---
drivers/iommu/riscv/iommu.c | 66 +++++++++++++++++++++++++++++++++++++
1 file changed, 66 insertions(+)

diff --git a/drivers/iommu/riscv/iommu.c b/drivers/iommu/riscv/iommu.c
index 3c5a6b49669d..b8e0e4b62585 100644
--- a/drivers/iommu/riscv/iommu.c
+++ b/drivers/iommu/riscv/iommu.c
@@ -17,6 +17,7 @@
#include <linux/init.h>
#include <linux/iommu.h>
#include <linux/kernel.h>
+#include <linux/pci.h>

#include "iommu-bits.h"
#include "iommu.h"
@@ -36,6 +37,60 @@ static void riscv_iommu_disable(struct riscv_iommu_device *iommu)
riscv_iommu_writel(iommu, RISCV_IOMMU_REG_PQCSR, 0);
}

+static int riscv_iommu_attach_identity_domain(struct iommu_domain *iommu_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 || !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 const struct iommu_ops riscv_iommu_ops = {
+ .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,
+};
+
static int riscv_iommu_init_check(struct riscv_iommu_device *iommu)
{
u64 ddtp;
@@ -71,6 +126,7 @@ 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);
}

@@ -95,5 +151,15 @@ int riscv_iommu_init(struct riscv_iommu_device *iommu)
return dev_err_probe(iommu->dev, rc,
"cannot register sysfs interface\n");

+ rc = iommu_device_register(&iommu->iommu, &riscv_iommu_ops, iommu->dev);
+ if (rc) {
+ dev_err_probe(iommu->dev, rc, "cannot register iommu interface\n");
+ goto err_remove_sysfs;
+ }
+
return 0;
+
+err_remove_sysfs:
+ iommu_device_sysfs_remove(&iommu->iommu);
+ return rc;
}
--
2.34.1