Re: [RFC PATCH 1/8] of/device: Allow specifying a custom iommu_spec to of_dma_configure
From: Robin Murphy
Date: Tue Feb 16 2021 - 07:48:54 EST
Hi Mikko,
On 2021-02-08 16:38, Mikko Perttunen wrote:
To allow for more customized device tree bindings that point to IOMMUs,
allow manual specification of iommu_spec to of_dma_configure.
The initial use case for this is with Host1x, where the driver manages
a set of device tree-defined IOMMU contexts that are dynamically
allocated to various users. These contexts don't correspond to
platform devices and are instead attached to dummy devices on a custom
software bus.
I'd suggest taking a closer look at the patches that made this
of_dma_configure_id() in the first place, and the corresponding bus code
in fsl-mc. At this level, Host1x sounds effectively identical to DPAA2
in terms of being a bus of logical devices composed from bits of
implicit behind-the-scenes hardware. I mean, compare your series title
to the fact that their identifiers are literally named "Isolation
Context ID" ;)
Please just use the existing mechanisms to describe a mapping between
Host1x context IDs and SMMU Stream IDs, rather than what looks like a
giant hacky mess here.
(This also reminds me I wanted to rip out all the PCI special-cases and
convert pci_dma_configure() over to passing its own IDs too, so thanks
for the memory-jog...)
Robin.
Signed-off-by: Mikko Perttunen <mperttunen@xxxxxxxxxx>
---
drivers/iommu/of_iommu.c | 12 ++++++++----
drivers/of/device.c | 9 +++++----
include/linux/of_device.h | 34 +++++++++++++++++++++++++++-------
include/linux/of_iommu.h | 6 ++++--
4 files changed, 44 insertions(+), 17 deletions(-)
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index e505b9130a1c..3fefa6c63863 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -87,8 +87,7 @@ int of_get_dma_window(struct device_node *dn, const char *prefix, int index,
}
EXPORT_SYMBOL_GPL(of_get_dma_window);
-static int of_iommu_xlate(struct device *dev,
- struct of_phandle_args *iommu_spec)
+int 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;
@@ -117,6 +116,7 @@ static int of_iommu_xlate(struct device *dev,
module_put(ops->owner);
return ret;
}
+EXPORT_SYMBOL_GPL(of_iommu_xlate);
static int of_iommu_configure_dev_id(struct device_node *master_np,
struct device *dev,
@@ -177,7 +177,8 @@ static int of_iommu_configure_device(struct device_node *master_np,
const struct iommu_ops *of_iommu_configure(struct device *dev,
struct device_node *master_np,
- const u32 *id)
+ const u32 *id,
+ struct of_phandle_args *iommu_spec)
{
const struct iommu_ops *ops = NULL;
struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
@@ -209,7 +210,10 @@ const struct iommu_ops *of_iommu_configure(struct device *dev,
err = pci_for_each_dma_alias(to_pci_dev(dev),
of_pci_iommu_init, &info);
} else {
- err = of_iommu_configure_device(master_np, dev, id);
+ if (iommu_spec)
+ err = of_iommu_xlate(dev, iommu_spec);
+ else
+ err = of_iommu_configure_device(master_np, dev, id);
fwspec = dev_iommu_fwspec_get(dev);
if (!err && fwspec)
diff --git a/drivers/of/device.c b/drivers/of/device.c
index aedfaaafd3e7..84ada2110c5b 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -88,8 +88,9 @@ int of_device_add(struct platform_device *ofdev)
* can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
* to fix up DMA configuration.
*/
-int of_dma_configure_id(struct device *dev, struct device_node *np,
- bool force_dma, const u32 *id)
+int __of_dma_configure(struct device *dev, struct device_node *np,
+ bool force_dma, const u32 *id,
+ struct of_phandle_args *iommu_spec)
{
const struct iommu_ops *iommu;
const struct bus_dma_region *map = NULL;
@@ -170,7 +171,7 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,
dev_dbg(dev, "device is%sdma coherent\n",
coherent ? " " : " not ");
- iommu = of_iommu_configure(dev, np, id);
+ iommu = of_iommu_configure(dev, np, id, iommu_spec);
if (PTR_ERR(iommu) == -EPROBE_DEFER) {
kfree(map);
return -EPROBE_DEFER;
@@ -184,7 +185,7 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,
dev->dma_range_map = map;
return 0;
}
-EXPORT_SYMBOL_GPL(of_dma_configure_id);
+EXPORT_SYMBOL_GPL(__of_dma_configure);
int of_device_register(struct platform_device *pdev)
{
diff --git a/include/linux/of_device.h b/include/linux/of_device.h
index 07ca187fc5e4..40cc3e788cb9 100644
--- a/include/linux/of_device.h
+++ b/include/linux/of_device.h
@@ -55,14 +55,27 @@ static inline struct device_node *of_cpu_device_node_get(int cpu)
return of_node_get(cpu_dev->of_node);
}
-int of_dma_configure_id(struct device *dev,
+int __of_dma_configure(struct device *dev,
struct device_node *np,
- bool force_dma, const u32 *id);
+ bool force_dma, const u32 *id,
+ struct of_phandle_args *iommu_spec);
static inline int of_dma_configure(struct device *dev,
struct device_node *np,
bool force_dma)
{
- return of_dma_configure_id(dev, np, force_dma, NULL);
+ return __of_dma_configure(dev, np, force_dma, NULL, NULL);
+}
+static inline int of_dma_configure_id(struct device *dev,
+ struct device_node *np,
+ bool force_dma, const u32 *id)
+{
+ return __of_dma_configure(dev, np, force_dma, id, NULL);
+}
+static inline int
+of_dma_configure_iommu_spec(struct device *dev, struct device_node *np,
+ bool force_dma, struct of_phandle_args *iommu_spec)
+{
+ return __of_dma_configure(dev, np, force_dma, NULL, iommu_spec);
}
#else /* CONFIG_OF */
@@ -112,18 +125,25 @@ static inline struct device_node *of_cpu_device_node_get(int cpu)
return NULL;
}
-static inline int of_dma_configure_id(struct device *dev,
+static inline int of_dma_configure(struct device *dev,
struct device_node *np,
bool force_dma)
{
return 0;
}
-static inline int of_dma_configure(struct device *dev,
- struct device_node *np,
- bool force_dma)
+
+static inline int of_dma_configure_id(struct device *dev,
+ struct device_node *np,
+ bool force_dma, const u32 *id)
{
return 0;
}
+
+static inline int
+of_dma_configure_iommu_spec(struct device *dev, struct device_node *np,
+ bool force_dma, struct of_phandle_args *iommu_spec)
+{ return 0;
+}
#endif /* CONFIG_OF */
#endif /* _LINUX_OF_DEVICE_H */
diff --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h
index 16f4b3e87f20..e8d1e6d32d77 100644
--- a/include/linux/of_iommu.h
+++ b/include/linux/of_iommu.h
@@ -14,7 +14,8 @@ extern int of_get_dma_window(struct device_node *dn, const char *prefix,
extern const struct iommu_ops *of_iommu_configure(struct device *dev,
struct device_node *master_np,
- const u32 *id);
+ const u32 *id,
+ struct of_phandle_args *iommu_spec);
#else
@@ -27,7 +28,8 @@ static inline int of_get_dma_window(struct device_node *dn, const char *prefix,
static inline const struct iommu_ops *of_iommu_configure(struct device *dev,
struct device_node *master_np,
- const u32 *id)
+ const u32 *id,
+ struct of_phandle_args *iommu_spec);
{
return NULL;
}