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Subject[PATCH V11 01/11] iommu/of: Refactor of_iommu_configure() for error handling
Date
From: Robin Murphy <robin.murphy@arm.com>

In preparation for some upcoming cleverness, rework the control flow in
of_iommu_configure() to minimise duplication and improve the propogation
of errors. It's also as good a time as any to switch over from the
now-just-a-compatibility-wrapper of_iommu_get_ops() to using the generic
IOMMU instance interface directly.

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
drivers/iommu/of_iommu.c | 83 +++++++++++++++++++++++++++++++-----------------
1 file changed, 53 insertions(+), 30 deletions(-)

diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 2683e9f..8f4e599 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -96,6 +96,28 @@ int of_get_dma_window(struct device_node *dn, const char *prefix, int index,
}
EXPORT_SYMBOL_GPL(of_get_dma_window);

+static const struct iommu_ops
+*of_iommu_xlate(struct device *dev, struct of_phandle_args *iommu_spec)
+{
+ const struct iommu_ops *ops;
+ struct fwnode_handle *fwnode = &iommu_spec->np->fwnode;
+ int err;
+
+ ops = iommu_ops_from_fwnode(fwnode);
+ if (!ops || !ops->of_xlate)
+ return NULL;
+
+ err = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
+ if (err)
+ return ERR_PTR(err);
+
+ err = ops->of_xlate(dev, iommu_spec);
+ if (err)
+ return ERR_PTR(err);
+
+ return ops;
+}
+
static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data)
{
struct of_phandle_args *iommu_spec = data;
@@ -105,10 +127,11 @@ static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data)
}

static const struct iommu_ops
-*of_pci_iommu_configure(struct pci_dev *pdev, struct device_node *bridge_np)
+*of_pci_iommu_init(struct pci_dev *pdev, struct device_node *bridge_np)
{
const struct iommu_ops *ops;
struct of_phandle_args iommu_spec;
+ int err;

/*
* Start by tracing the RID alias down the PCI topology as
@@ -123,56 +146,56 @@ static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data)
* bus into the system beyond, and which IOMMU it ends up at.
*/
iommu_spec.np = NULL;
- if (of_pci_map_rid(bridge_np, iommu_spec.args[0], "iommu-map",
- "iommu-map-mask", &iommu_spec.np, iommu_spec.args))
- return NULL;
+ err = of_pci_map_rid(bridge_np, iommu_spec.args[0], "iommu-map",
+ "iommu-map-mask", &iommu_spec.np,
+ iommu_spec.args);
+ if (err)
+ return err == -ENODEV ? NULL : ERR_PTR(err);

- ops = iommu_ops_from_fwnode(&iommu_spec.np->fwnode);
- if (!ops || !ops->of_xlate ||
- iommu_fwspec_init(&pdev->dev, &iommu_spec.np->fwnode, ops) ||
- ops->of_xlate(&pdev->dev, &iommu_spec))
- ops = NULL;
+ ops = of_iommu_xlate(&pdev->dev, &iommu_spec);

of_node_put(iommu_spec.np);
return ops;
}

-const struct iommu_ops *of_iommu_configure(struct device *dev,
- struct device_node *master_np)
+static const struct iommu_ops
+*of_platform_iommu_init(struct device *dev, struct device_node *np)
{
struct of_phandle_args iommu_spec;
- struct device_node *np;
const struct iommu_ops *ops = NULL;
int idx = 0;

- if (dev_is_pci(dev))
- return of_pci_iommu_configure(to_pci_dev(dev), master_np);
-
/*
* We don't currently walk up the tree looking for a parent IOMMU.
* See the `Notes:' section of
* Documentation/devicetree/bindings/iommu/iommu.txt
*/
- while (!of_parse_phandle_with_args(master_np, "iommus",
- "#iommu-cells", idx,
- &iommu_spec)) {
- np = iommu_spec.np;
- ops = iommu_ops_from_fwnode(&np->fwnode);
-
- if (!ops || !ops->of_xlate ||
- iommu_fwspec_init(dev, &np->fwnode, ops) ||
- ops->of_xlate(dev, &iommu_spec))
- goto err_put_node;
-
- of_node_put(np);
+ while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells",
+ idx, &iommu_spec)) {
+ ops = of_iommu_xlate(dev, &iommu_spec);
+ of_node_put(iommu_spec.np);
idx++;
+ if (IS_ERR_OR_NULL(ops))
+ break;
}

return ops;
+}
+
+const struct iommu_ops *of_iommu_configure(struct device *dev,
+ struct device_node *master_np)
+{
+ const struct iommu_ops *ops;
+
+ if (!master_np)
+ return NULL;
+
+ if (dev_is_pci(dev))
+ ops = of_pci_iommu_init(to_pci_dev(dev), master_np);
+ else
+ ops = of_platform_iommu_init(dev, master_np);

-err_put_node:
- of_node_put(np);
- return NULL;
+ return IS_ERR(ops) ? NULL : ops;
}

static int __init of_iommu_init(void)
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
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