diff mbox series

[v7,1/8] iommu/arm: Add iommu_dt_xlate()

Message ID 224570237ae19d10c554a14c6d8e34f171a3ce11.1738665272.git.mykyta_poturai@epam.com (mailing list archive)
State New
Headers show
Series SMMU handling for PCIe Passthrough on ARM | expand

Commit Message

Mykyta Poturai Feb. 4, 2025, 1:54 p.m. UTC 
From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

Move code for processing DT IOMMU specifier to a separate helper.
This helper will be re-used for adding PCI devices by the subsequent
patches as we will need exact the same actions for processing
DT PCI-IOMMU specifier.

While at it introduce NO_IOMMU to avoid magic "1".

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Signed-off-by: Stewart Hildebrand <stewart.hildebrand@amd.com>
Signed-off-by: Mykyta Poturai <mykyta_poturai@epam.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
---
v6->v7:
* explained NO_IOMMU in comments

v5->v6:
* pass ops parameter to iommu_dt_xlate()
* add Julien's R-b

v4->v5:
* rebase on top of "dynamic node programming using overlay dtbo" series
* move #define NO_IOMMU 1 to header
* s/these/this/ inside comment

v3->v4:
* make dt_phandle_args *iommu_spec const
* move !ops->add_device check to helper

v2->v3:
* no change

v1->v2:
* no change

downstream->v1:
* trivial rebase
* s/dt_iommu_xlate/iommu_dt_xlate/

(cherry picked from commit c26bab0415ca303df86aba1d06ef8edc713734d3 from
 the downstream branch poc/pci-passthrough from
 https://gitlab.com/xen-project/people/bmarquis/xen-arm-poc.git)
---
 xen/drivers/passthrough/device_tree.c | 48 +++++++++++++++++----------
 xen/include/xen/iommu.h               |  3 ++
 2 files changed, 33 insertions(+), 18 deletions(-)

Comments

Jan Beulich Feb. 4, 2025, 2:12 p.m. UTC | #1 
On 04.02.2025 14:54, Mykyta Poturai wrote:
> --- a/xen/include/xen/iommu.h
> +++ b/xen/include/xen/iommu.h
> @@ -238,6 +238,9 @@ int iommu_do_dt_domctl(struct xen_domctl *domctl, struct domain *d,
>   */
>  int iommu_remove_dt_device(struct dt_device_node *np);
>  
> +/* Error code for reporting no IOMMU is present */
> +#define NO_IOMMU    1

Hmm. The identifier is overly generic, and even the comment leaves open
whose error code this is.

Jan
diff mbox series

Patch

diff --git a/xen/drivers/passthrough/device_tree.c b/xen/drivers/passthrough/device_tree.c
index 075fb25a37..4c35281d98 100644
--- a/xen/drivers/passthrough/device_tree.c
+++ b/xen/drivers/passthrough/device_tree.c
@@ -137,6 +137,30 @@  int iommu_release_dt_devices(struct domain *d)
     return 0;
 }
 
+static int iommu_dt_xlate(struct device *dev,
+                          const struct dt_phandle_args *iommu_spec,
+                          const struct iommu_ops *ops)
+{
+    int rc;
+
+    if ( !ops->dt_xlate )
+        return -EINVAL;
+
+    if ( !dt_device_is_available(iommu_spec->np) )
+        return NO_IOMMU;
+
+    rc = iommu_fwspec_init(dev, &iommu_spec->np->dev);
+    if ( rc )
+        return rc;
+
+    /*
+     * Provide DT IOMMU specifier which describes the IOMMU master
+     * interfaces of that device (device IDs, etc) to the driver.
+     * The driver is responsible to decide how to interpret them.
+     */
+    return ops->dt_xlate(dev, iommu_spec);
+}
+
 int iommu_remove_dt_device(struct dt_device_node *np)
 {
     const struct iommu_ops *ops = iommu_get_ops();
@@ -146,7 +170,7 @@  int iommu_remove_dt_device(struct dt_device_node *np)
     ASSERT(rw_is_locked(&dt_host_lock));
 
     if ( !iommu_enabled )
-        return 1;
+        return NO_IOMMU;
 
     if ( !ops )
         return -EOPNOTSUPP;
@@ -187,12 +211,12 @@  int iommu_add_dt_device(struct dt_device_node *np)
     const struct iommu_ops *ops = iommu_get_ops();
     struct dt_phandle_args iommu_spec;
     struct device *dev = dt_to_dev(np);
-    int rc = 1, index = 0;
+    int rc = NO_IOMMU, index = 0;
 
     ASSERT(system_state < SYS_STATE_active || rw_is_locked(&dt_host_lock));
 
     if ( !iommu_enabled )
-        return 1;
+        return NO_IOMMU;
 
     if ( !ops )
         return -EINVAL;
@@ -215,27 +239,15 @@  int iommu_add_dt_device(struct dt_device_node *np)
     {
         /*
          * The driver which supports generic IOMMU DT bindings must have
-         * these callback implemented.
+         * this callback implemented.
          */
-        if ( !ops->add_device || !ops->dt_xlate )
+        if ( !ops->add_device )
         {
             rc = -EINVAL;
             goto fail;
         }
 
-        if ( !dt_device_is_available(iommu_spec.np) )
-            break;
-
-        rc = iommu_fwspec_init(dev, &iommu_spec.np->dev);
-        if ( rc )
-            break;
-
-        /*
-         * Provide DT IOMMU specifier which describes the IOMMU master
-         * interfaces of that device (device IDs, etc) to the driver.
-         * The driver is responsible to decide how to interpret them.
-         */
-        rc = ops->dt_xlate(dev, &iommu_spec);
+        rc = iommu_dt_xlate(dev, &iommu_spec, ops);
         if ( rc )
             break;
 
diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index b928c67e19..c3b8df9815 100644
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -238,6 +238,9 @@  int iommu_do_dt_domctl(struct xen_domctl *domctl, struct domain *d,
  */
 int iommu_remove_dt_device(struct dt_device_node *np);
 
+/* Error code for reporting no IOMMU is present */
+#define NO_IOMMU    1
+
 #endif /* HAS_DEVICE_TREE */
 
 struct page_info;