Re: [PATCH v2 2/5] iommu: Implement of_iommu_get_resv_regions()
On Sat, Jul 17, 2021 at 02:07:12PM +0300, Dmitry Osipenko wrote:
> 16.07.2021 17:41, Rob Herring пишет:
> > On Fri, Jul 2, 2021 at 8:05 AM Dmitry Osipenko wrote:
> >>
> >> 23.04.2021 19:32, Thierry Reding пишет:
> >>> +void of_iommu_get_resv_regions(struct device *dev, struct list_head
> >>> *list)
> >>> +{
> >>> + struct of_phandle_iterator it;
> >>> + int err;
> >>> +
> >>> + of_for_each_phandle(&it, err, dev->of_node, "memory-region",
> >>> "#memory-region-cells", 0) {
> >>> + struct iommu_resv_region *region;
> >>> + struct of_phandle_args args;
> >>> + struct resource res;
> >>> +
> >>> + args.args_count = of_phandle_iterator_args(&it, args.args,
> >>> MAX_PHANDLE_ARGS);
> >>> +
> >>> + err = of_address_to_resource(it.node, 0, &res);
> >>> + if (err < 0) {
> >>> + dev_err(dev, "failed to parse memory region %pOF:
> >>> %d\n",
> >>> + it.node, err);
> >>> + continue;
> >>> + }
> >>> +
> >>> + if (args.args_count > 0) {
> >>> + /*
> >>> + * Active memory regions are expected to be
> >>> accessed by hardware during
> >>> + * boot and must therefore have an identity mapping
> >>> created prior to the
> >>> + * driver taking control of the hardware. This
> >>> ensures that non-quiescent
> >>> + * hardware doesn't cause IOMMU faults during boot.
> >>> + */
> >>> + if (args.args[0] & MEMORY_REGION_IDENTITY_MAPPING) {
> >>> + region = iommu_alloc_resv_region(res.start,
> >>> resource_size(&res),
> >>> + IOMMU_READ
> >>> | IOMMU_WRITE,
> >>> +
> >>> IOMMU_RESV_DIRECT_RELAXABLE);
> >>> + if (!region)
> >>> + continue;
> >>> +
> >>> + list_add_tail(®ion->list, list);
> >>> + }
> >>> + }
> >>> + }
> >>> +}
> >>> +EXPORT_SYMBOL(of_iommu_get_resv_regions);
> >>
> >> Any reason why this is not EXPORT_SYMBOL_GPL? I'm curious what is the
> >> logic behind the OF symbols in general since it looks like half of them
> >> are GPL.
> >
> > Generally, new ones are _GPL. Old ones probably predate _GPL.
> >
> > This one is up to the IOMMU maintainers.
>
> Thank you.
I prefer EXPORT_SYMBOL_GPL(). That's aligned with the symbols exported by
iommu.c, with the *single* exception of generic_iommu_put_resv_regions(),
which I think should be changed to _GPL() as well.
Will
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Re: [PATCH v2 2/5] iommu: Implement of_iommu_get_resv_regions()
16.07.2021 17:41, Rob Herring пишет:
> On Fri, Jul 2, 2021 at 8:05 AM Dmitry Osipenko wrote:
>>
>> 23.04.2021 19:32, Thierry Reding пишет:
>>> +void of_iommu_get_resv_regions(struct device *dev, struct list_head *list)
>>> +{
>>> + struct of_phandle_iterator it;
>>> + int err;
>>> +
>>> + of_for_each_phandle(&it, err, dev->of_node, "memory-region",
>>> "#memory-region-cells", 0) {
>>> + struct iommu_resv_region *region;
>>> + struct of_phandle_args args;
>>> + struct resource res;
>>> +
>>> + args.args_count = of_phandle_iterator_args(&it, args.args,
>>> MAX_PHANDLE_ARGS);
>>> +
>>> + err = of_address_to_resource(it.node, 0, &res);
>>> + if (err < 0) {
>>> + dev_err(dev, "failed to parse memory region %pOF:
>>> %d\n",
>>> + it.node, err);
>>> + continue;
>>> + }
>>> +
>>> + if (args.args_count > 0) {
>>> + /*
>>> + * Active memory regions are expected to be accessed
>>> by hardware during
>>> + * boot and must therefore have an identity mapping
>>> created prior to the
>>> + * driver taking control of the hardware. This
>>> ensures that non-quiescent
>>> + * hardware doesn't cause IOMMU faults during boot.
>>> + */
>>> + if (args.args[0] & MEMORY_REGION_IDENTITY_MAPPING) {
>>> + region = iommu_alloc_resv_region(res.start,
>>> resource_size(&res),
>>> + IOMMU_READ |
>>> IOMMU_WRITE,
>>> +
>>> IOMMU_RESV_DIRECT_RELAXABLE);
>>> + if (!region)
>>> + continue;
>>> +
>>> + list_add_tail(®ion->list, list);
>>> + }
>>> + }
>>> + }
>>> +}
>>> +EXPORT_SYMBOL(of_iommu_get_resv_regions);
>>
>> Any reason why this is not EXPORT_SYMBOL_GPL? I'm curious what is the
>> logic behind the OF symbols in general since it looks like half of them
>> are GPL.
>
> Generally, new ones are _GPL. Old ones probably predate _GPL.
>
> This one is up to the IOMMU maintainers.
Thank you.
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Re: [PATCH v2 2/5] iommu: Implement of_iommu_get_resv_regions()
On Fri, Jul 2, 2021 at 8:05 AM Dmitry Osipenko wrote:
>
> 23.04.2021 19:32, Thierry Reding пишет:
> > +void of_iommu_get_resv_regions(struct device *dev, struct list_head *list)
> > +{
> > + struct of_phandle_iterator it;
> > + int err;
> > +
> > + of_for_each_phandle(&it, err, dev->of_node, "memory-region",
> > "#memory-region-cells", 0) {
> > + struct iommu_resv_region *region;
> > + struct of_phandle_args args;
> > + struct resource res;
> > +
> > + args.args_count = of_phandle_iterator_args(&it, args.args,
> > MAX_PHANDLE_ARGS);
> > +
> > + err = of_address_to_resource(it.node, 0, &res);
> > + if (err < 0) {
> > + dev_err(dev, "failed to parse memory region %pOF:
> > %d\n",
> > + it.node, err);
> > + continue;
> > + }
> > +
> > + if (args.args_count > 0) {
> > + /*
> > + * Active memory regions are expected to be accessed
> > by hardware during
> > + * boot and must therefore have an identity mapping
> > created prior to the
> > + * driver taking control of the hardware. This
> > ensures that non-quiescent
> > + * hardware doesn't cause IOMMU faults during boot.
> > + */
> > + if (args.args[0] & MEMORY_REGION_IDENTITY_MAPPING) {
> > + region = iommu_alloc_resv_region(res.start,
> > resource_size(&res),
> > + IOMMU_READ |
> > IOMMU_WRITE,
> > +
> > IOMMU_RESV_DIRECT_RELAXABLE);
> > + if (!region)
> > + continue;
> > +
> > + list_add_tail(®ion->list, list);
> > + }
> > + }
> > + }
> > +}
> > +EXPORT_SYMBOL(of_iommu_get_resv_regions);
>
> Any reason why this is not EXPORT_SYMBOL_GPL? I'm curious what is the
> logic behind the OF symbols in general since it looks like half of them
> are GPL.
Generally, new ones are _GPL. Old ones probably predate _GPL.
This one is up to the IOMMU maintainers.
Rob
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Re: [PATCH v2 2/5] iommu: Implement of_iommu_get_resv_regions()
23.04.2021 19:32, Thierry Reding пишет:
> +void of_iommu_get_resv_regions(struct device *dev, struct list_head *list)
> +{
> + struct of_phandle_iterator it;
> + int err;
> +
> + of_for_each_phandle(&it, err, dev->of_node, "memory-region",
> "#memory-region-cells", 0) {
> + struct iommu_resv_region *region;
> + struct of_phandle_args args;
> + struct resource res;
> +
> + args.args_count = of_phandle_iterator_args(&it, args.args,
> MAX_PHANDLE_ARGS);
> +
> + err = of_address_to_resource(it.node, 0, &res);
> + if (err < 0) {
> + dev_err(dev, "failed to parse memory region %pOF: %d\n",
> + it.node, err);
> + continue;
> + }
> +
> + if (args.args_count > 0) {
> + /*
> + * Active memory regions are expected to be accessed by
> hardware during
> + * boot and must therefore have an identity mapping
> created prior to the
> + * driver taking control of the hardware. This ensures
> that non-quiescent
> + * hardware doesn't cause IOMMU faults during boot.
> + */
> + if (args.args[0] & MEMORY_REGION_IDENTITY_MAPPING) {
> + region = iommu_alloc_resv_region(res.start,
> resource_size(&res),
> + IOMMU_READ |
> IOMMU_WRITE,
> +
> IOMMU_RESV_DIRECT_RELAXABLE);
> + if (!region)
> + continue;
> +
> + list_add_tail(®ion->list, list);
> + }
> + }
> + }
> +}
> +EXPORT_SYMBOL(of_iommu_get_resv_regions);
Any reason why this is not EXPORT_SYMBOL_GPL? I'm curious what is the
logic behind the OF symbols in general since it looks like half of them
are GPL.
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[PATCH v2 2/5] iommu: Implement of_iommu_get_resv_regions()
From: Thierry Reding
This is an implementation that IOMMU drivers can use to obtain reserved
memory regions from a device tree node. It uses the reserved-memory DT
bindings to find the regions associated with a given device. If these
regions are marked accordingly, identity mappings will be created for
them in the IOMMU domain that the devices will be attached to.
Cc: Frank Rowand
Cc: devicet...@vger.kernel.org
Reviewed-by: Rob Herring
Signed-off-by: Thierry Reding
---
Changes in v3:
- change "active" property to identity mapping flag that is part of the
memory region specifier (as defined by #memory-region-cells) to allow
per-reference flags to be used
Changes in v2:
- use "active" property to determine whether direct mappings are needed
---
drivers/iommu/of_iommu.c | 54
include/linux/of_iommu.h | 8 ++
2 files changed, 62 insertions(+)
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index a9d2df001149..321ebd5fdaba 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -11,12 +11,15 @@
#include
#include
#include
+#include
#include
#include
#include
#include
#include
+#include
+
#define NO_IOMMU 1
/**
@@ -240,3 +243,54 @@ const struct iommu_ops *of_iommu_configure(struct device
*dev,
return ops;
}
+
+/**
+ * of_iommu_get_resv_regions - reserved region driver helper for device tree
+ * @dev: device for which to get reserved regions
+ * @list: reserved region list
+ *
+ * IOMMU drivers can use this to implement their .get_resv_regions() callback
+ * for memory regions attached to a device tree node. See the reserved-memory
+ * device tree bindings on how to use these:
+ *
+ * Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
+ */
+void of_iommu_get_resv_regions(struct device *dev, struct list_head *list)
+{
+ struct of_phandle_iterator it;
+ int err;
+
+ of_for_each_phandle(&it, err, dev->of_node, "memory-region",
"#memory-region-cells", 0) {
+ struct iommu_resv_region *region;
+ struct of_phandle_args args;
+ struct resource res;
+
+ args.args_count = of_phandle_iterator_args(&it, args.args,
MAX_PHANDLE_ARGS);
+
+ err = of_address_to_resource(it.node, 0, &res);
+ if (err < 0) {
+ dev_err(dev, "failed to parse memory region %pOF: %d\n",
+ it.node, err);
+ continue;
+ }
+
+ if (args.args_count > 0) {
+ /*
+* Active memory regions are expected to be accessed by
hardware during
+* boot and must therefore have an identity mapping
created prior to the
+* driver taking control of the hardware. This ensures
that non-quiescent
+* hardware doesn't cause IOMMU faults during boot.
+*/
+ if (args.args[0] & MEMORY_REGION_IDENTITY_MAPPING) {
+ region = iommu_alloc_resv_region(res.start,
resource_size(&res),
+IOMMU_READ |
IOMMU_WRITE,
+
IOMMU_RESV_DIRECT_RELAXABLE);
+ if (!region)
+ continue;
+
+ list_add_tail(®ion->list, list);
+ }
+ }
+ }
+}
+EXPORT_SYMBOL(of_iommu_get_resv_regions);
diff --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h
index 16f4b3e87f20..8412437acaac 100644
--- a/include/linux/of_iommu.h
+++ b/include/linux/of_iommu.h
@@ -16,6 +16,9 @@ extern const struct iommu_ops *of_iommu_configure(struct
device *dev,
struct device_node *master_np,
const u32 *id);
+extern void of_iommu_get_resv_regions(struct device *dev,
+ struct list_head *list);
+
#else
static inline int of_get_dma_window(struct device_node *dn, const char *prefix,
@@ -32,6 +35,11 @@ static inline const struct iommu_ops
*of_iommu_configure(struct device *dev,
return NULL;
}
+static inline void of_iommu_get_resv_regions(struct device *dev,
+struct list_head *list)
+{
+}
+
#endif /* CONFIG_OF_IOMMU */
#endif /* __OF_IOMMU_H */
--
2.30.2
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