[PATCH v2 4/7] iommu/riscv: Enable IOMMU registration and device probe.

Tomasz Jeznach
2024-04-18T17:46:28Z

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