Re: [PATCH v5 16/16] of: Add plumbing for restricted DMA pool
On Fri, Apr 23, 2021 at 9:35 PM Robin Murphy wrote:
>
> On 2021-04-22 09:15, Claire Chang wrote:
> > If a device is not behind an IOMMU, we look up the device node and set
> > up the restricted DMA when the restricted-dma-pool is presented.
> >
> > Signed-off-by: Claire Chang
> > ---
> > drivers/of/address.c| 25 +
> > drivers/of/device.c | 3 +++
> > drivers/of/of_private.h | 5 +
> > 3 files changed, 33 insertions(+)
> >
> > diff --git a/drivers/of/address.c b/drivers/of/address.c
> > index 54f221dde267..fff3adfe4986 100644
> > --- a/drivers/of/address.c
> > +++ b/drivers/of/address.c
> > @@ -8,6 +8,7 @@
> > #include
> > #include
> > #include
> > +#include
> > #include
> > #include
> > #include
> > @@ -1109,6 +1110,30 @@ bool of_dma_is_coherent(struct device_node *np)
> > }
> > EXPORT_SYMBOL_GPL(of_dma_is_coherent);
> >
> > +int of_dma_set_restricted_buffer(struct device *dev)
> > +{
> > + struct device_node *node;
> > + int count, i;
> > +
> > + if (!dev->of_node)
> > + return 0;
> > +
> > + count = of_property_count_elems_of_size(dev->of_node, "memory-region",
> > + sizeof(phandle));
> > + for (i = 0; i < count; i++) {
> > + node = of_parse_phandle(dev->of_node, "memory-region", i);
> > + /* There might be multiple memory regions, but only one
> > + * restriced-dma-pool region is allowed.
> > + */
>
> What's the use-case for having multiple regions if the restricted pool
> is by definition the only one accessible?
There might be a device coherent pool (shared-dma-pool) and
dma_alloc_attrs might allocate memory from that pool [1].
I'm not sure if it makes sense to have another device coherent pool
while using restricted DMA pool though.
[1] https://elixir.bootlin.com/linux/v5.12/source/kernel/dma/mapping.c#L435
>
> Robin.
>
> > + if (of_device_is_compatible(node, "restricted-dma-pool") &&
> > + of_device_is_available(node))
> > + return of_reserved_mem_device_init_by_idx(
> > + dev, dev->of_node, i);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > /**
> >* of_mmio_is_nonposted - Check if device uses non-posted MMIO
> >* @np: device node
> > diff --git a/drivers/of/device.c b/drivers/of/device.c
> > index c5a9473a5fb1..d8d865223e51 100644
> > --- a/drivers/of/device.c
> > +++ b/drivers/of/device.c
> > @@ -165,6 +165,9 @@ int of_dma_configure_id(struct device *dev, struct
> > device_node *np,
> >
> > arch_setup_dma_ops(dev, dma_start, size, iommu, coherent);
> >
> > + if (!iommu)
> > + return of_dma_set_restricted_buffer(dev);
> > +
> > return 0;
> > }
> > EXPORT_SYMBOL_GPL(of_dma_configure_id);
> > diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
> > index d717efbd637d..e9237f5eff48 100644
> > --- a/drivers/of/of_private.h
> > +++ b/drivers/of/of_private.h
> > @@ -163,12 +163,17 @@ struct bus_dma_region;
> > #if defined(CONFIG_OF_ADDRESS) && defined(CONFIG_HAS_DMA)
> > int of_dma_get_range(struct device_node *np,
> > const struct bus_dma_region **map);
> > +int of_dma_set_restricted_buffer(struct device *dev);
> > #else
> > static inline int of_dma_get_range(struct device_node *np,
> > const struct bus_dma_region **map)
> > {
> > return -ENODEV;
> > }
> > +static inline int of_dma_get_restricted_buffer(struct device *dev)
> > +{
> > + return -ENODEV;
> > +}
> > #endif
> >
> > #endif /* _LINUX_OF_PRIVATE_H */
> >
Re: [PATCH v5 16/16] of: Add plumbing for restricted DMA pool
On 2021-04-22 09:15, Claire Chang wrote:
If a device is not behind an IOMMU, we look up the device node and set
up the restricted DMA when the restricted-dma-pool is presented.
Signed-off-by: Claire Chang
---
drivers/of/address.c| 25 +
drivers/of/device.c | 3 +++
drivers/of/of_private.h | 5 +
3 files changed, 33 insertions(+)
diff --git a/drivers/of/address.c b/drivers/of/address.c
index 54f221dde267..fff3adfe4986 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -8,6 +8,7 @@
#include
#include
#include
+#include
#include
#include
#include
@@ -1109,6 +1110,30 @@ bool of_dma_is_coherent(struct device_node *np)
}
EXPORT_SYMBOL_GPL(of_dma_is_coherent);
+int of_dma_set_restricted_buffer(struct device *dev)
+{
+ struct device_node *node;
+ int count, i;
+
+ if (!dev->of_node)
+ return 0;
+
+ count = of_property_count_elems_of_size(dev->of_node, "memory-region",
+ sizeof(phandle));
+ for (i = 0; i < count; i++) {
+ node = of_parse_phandle(dev->of_node, "memory-region", i);
+ /* There might be multiple memory regions, but only one
+* restriced-dma-pool region is allowed.
+*/
What's the use-case for having multiple regions if the restricted pool
is by definition the only one accessible?
Robin.
+ if (of_device_is_compatible(node, "restricted-dma-pool") &&
+ of_device_is_available(node))
+ return of_reserved_mem_device_init_by_idx(
+ dev, dev->of_node, i);
+ }
+
+ return 0;
+}
+
/**
* of_mmio_is_nonposted - Check if device uses non-posted MMIO
* @np: device node
diff --git a/drivers/of/device.c b/drivers/of/device.c
index c5a9473a5fb1..d8d865223e51 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -165,6 +165,9 @@ int of_dma_configure_id(struct device *dev, struct
device_node *np,
arch_setup_dma_ops(dev, dma_start, size, iommu, coherent);
+ if (!iommu)
+ return of_dma_set_restricted_buffer(dev);
+
return 0;
}
EXPORT_SYMBOL_GPL(of_dma_configure_id);
diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index d717efbd637d..e9237f5eff48 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h
@@ -163,12 +163,17 @@ struct bus_dma_region;
#if defined(CONFIG_OF_ADDRESS) && defined(CONFIG_HAS_DMA)
int of_dma_get_range(struct device_node *np,
const struct bus_dma_region **map);
+int of_dma_set_restricted_buffer(struct device *dev);
#else
static inline int of_dma_get_range(struct device_node *np,
const struct bus_dma_region **map)
{
return -ENODEV;
}
+static inline int of_dma_get_restricted_buffer(struct device *dev)
+{
+ return -ENODEV;
+}
#endif
#endif /* _LINUX_OF_PRIVATE_H */
Re: [PATCH v5 16/16] of: Add plumbing for restricted DMA pool
On Thu, Apr 22, 2021 at 4:17 PM Claire Chang wrote:
>
> If a device is not behind an IOMMU, we look up the device node and set
> up the restricted DMA when the restricted-dma-pool is presented.
>
> Signed-off-by: Claire Chang
> ---
> drivers/of/address.c| 25 +
> drivers/of/device.c | 3 +++
> drivers/of/of_private.h | 5 +
> 3 files changed, 33 insertions(+)
>
> diff --git a/drivers/of/address.c b/drivers/of/address.c
> index 54f221dde267..fff3adfe4986 100644
> --- a/drivers/of/address.c
> +++ b/drivers/of/address.c
> @@ -8,6 +8,7 @@
> #include
> #include
> #include
> +#include
> #include
> #include
> #include
> @@ -1109,6 +1110,30 @@ bool of_dma_is_coherent(struct device_node *np)
> }
> EXPORT_SYMBOL_GPL(of_dma_is_coherent);
>
> +int of_dma_set_restricted_buffer(struct device *dev)
> +{
> + struct device_node *node;
> + int count, i;
> +
> + if (!dev->of_node)
> + return 0;
> +
> + count = of_property_count_elems_of_size(dev->of_node, "memory-region",
> + sizeof(phandle));
> + for (i = 0; i < count; i++) {
> + node = of_parse_phandle(dev->of_node, "memory-region", i);
> + /* There might be multiple memory regions, but only one
> +* restriced-dma-pool region is allowed.
> +*/
> + if (of_device_is_compatible(node, "restricted-dma-pool") &&
> + of_device_is_available(node))
> + return of_reserved_mem_device_init_by_idx(
> + dev, dev->of_node, i);
> + }
> +
> + return 0;
> +}
> +
> /**
> * of_mmio_is_nonposted - Check if device uses non-posted MMIO
> * @np:device node
> diff --git a/drivers/of/device.c b/drivers/of/device.c
> index c5a9473a5fb1..d8d865223e51 100644
> --- a/drivers/of/device.c
> +++ b/drivers/of/device.c
> @@ -165,6 +165,9 @@ int of_dma_configure_id(struct device *dev, struct
> device_node *np,
>
> arch_setup_dma_ops(dev, dma_start, size, iommu, coherent);
>
> + if (!iommu)
> + return of_dma_set_restricted_buffer(dev);
> +
> return 0;
> }
> EXPORT_SYMBOL_GPL(of_dma_configure_id);
> diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
> index d717efbd637d..e9237f5eff48 100644
> --- a/drivers/of/of_private.h
> +++ b/drivers/of/of_private.h
> @@ -163,12 +163,17 @@ struct bus_dma_region;
> #if defined(CONFIG_OF_ADDRESS) && defined(CONFIG_HAS_DMA)
> int of_dma_get_range(struct device_node *np,
> const struct bus_dma_region **map);
> +int of_dma_set_restricted_buffer(struct device *dev);
> #else
> static inline int of_dma_get_range(struct device_node *np,
> const struct bus_dma_region **map)
> {
> return -ENODEV;
> }
> +static inline int of_dma_get_restricted_buffer(struct device *dev)
This one should be of_dma_set_restricted_buffer. Sorry for the typo.
> +{
> + return -ENODEV;
> +}
> #endif
>
> #endif /* _LINUX_OF_PRIVATE_H */
> --
> 2.31.1.368.gbe11c130af-goog
>
[PATCH v5 16/16] of: Add plumbing for restricted DMA pool
If a device is not behind an IOMMU, we look up the device node and set
up the restricted DMA when the restricted-dma-pool is presented.
Signed-off-by: Claire Chang
---
drivers/of/address.c| 25 +
drivers/of/device.c | 3 +++
drivers/of/of_private.h | 5 +
3 files changed, 33 insertions(+)
diff --git a/drivers/of/address.c b/drivers/of/address.c
index 54f221dde267..fff3adfe4986 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -8,6 +8,7 @@
#include
#include
#include
+#include
#include
#include
#include
@@ -1109,6 +1110,30 @@ bool of_dma_is_coherent(struct device_node *np)
}
EXPORT_SYMBOL_GPL(of_dma_is_coherent);
+int of_dma_set_restricted_buffer(struct device *dev)
+{
+ struct device_node *node;
+ int count, i;
+
+ if (!dev->of_node)
+ return 0;
+
+ count = of_property_count_elems_of_size(dev->of_node, "memory-region",
+ sizeof(phandle));
+ for (i = 0; i < count; i++) {
+ node = of_parse_phandle(dev->of_node, "memory-region", i);
+ /* There might be multiple memory regions, but only one
+* restriced-dma-pool region is allowed.
+*/
+ if (of_device_is_compatible(node, "restricted-dma-pool") &&
+ of_device_is_available(node))
+ return of_reserved_mem_device_init_by_idx(
+ dev, dev->of_node, i);
+ }
+
+ return 0;
+}
+
/**
* of_mmio_is_nonposted - Check if device uses non-posted MMIO
* @np:device node
diff --git a/drivers/of/device.c b/drivers/of/device.c
index c5a9473a5fb1..d8d865223e51 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -165,6 +165,9 @@ int of_dma_configure_id(struct device *dev, struct
device_node *np,
arch_setup_dma_ops(dev, dma_start, size, iommu, coherent);
+ if (!iommu)
+ return of_dma_set_restricted_buffer(dev);
+
return 0;
}
EXPORT_SYMBOL_GPL(of_dma_configure_id);
diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index d717efbd637d..e9237f5eff48 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h
@@ -163,12 +163,17 @@ struct bus_dma_region;
#if defined(CONFIG_OF_ADDRESS) && defined(CONFIG_HAS_DMA)
int of_dma_get_range(struct device_node *np,
const struct bus_dma_region **map);
+int of_dma_set_restricted_buffer(struct device *dev);
#else
static inline int of_dma_get_range(struct device_node *np,
const struct bus_dma_region **map)
{
return -ENODEV;
}
+static inline int of_dma_get_restricted_buffer(struct device *dev)
+{
+ return -ENODEV;
+}
#endif
#endif /* _LINUX_OF_PRIVATE_H */
--
2.31.1.368.gbe11c130af-goog
