Re: [PATCH v5 2/5] iommu: Implement of_iommu_get_resv_regions()
On Sun, May 15, 2022 at 01:10:38PM +0200, Janne Grunau wrote:
> On 2022-05-12 21:00:49 +0200, Thierry Reding wrote:
> > 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.
> >
> > Signed-off-by: Thierry Reding
> > ---
> > Changes in v5:
> > - update for new "iommu-addresses" device tree bindings
> >
> > Changes in v4:
> > - fix build failure on !CONFIG_OF_ADDRESS
> >
> > 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 | 90
> > include/linux/of_iommu.h | 8
> > 2 files changed, 98 insertions(+)
> >
> > diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
> > index 5696314ae69e..9e341b5e307f 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
> >
> > static int of_iommu_xlate(struct device *dev,
> > @@ -172,3 +175,90 @@ 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)
> > +{
> > +#if IS_ENABLED(CONFIG_OF_ADDRESS)
> > + struct of_phandle_iterator it;
> > + int err;
> > +
> > + of_for_each_phandle(, err, dev->of_node, "memory-region", NULL, 0) {
> > + struct iommu_resv_region *region;
> > + struct resource res;
> > + const __be32 *maps;
> > + int size;
>
> Adding 'if (!of_device_is_available(it.node)) continue;' here would help
> backwards compatibility. My plan was to add the reserved regions with
> "iommu-addresses" with all zero adresses and sizes with status =
> "disabled" to the devicetree. A bootloader update is required to fill
> those.
Yes, good point. My plan was originally to have the bootloader/firmware
generate these nodes in their entirety, but yeah, prepopulating them and
having firmware just fill in updated values and setting status = "okay"
seems reasonable to me.
> > +
> > + memset(, 0, sizeof(res));
> > +
> > + /*
> > +* The "reg" property is optional and can be omitted by
> > reserved-memory regions
> > +* that represent reservations in the IOVA space, which are
> > regions that should
> > +* not be mapped.
> > +*/
> > + if (of_find_property(it.node, "reg", NULL)) {
> > + err = of_address_to_resource(it.node, 0, );
> > + if (err < 0) {
> > + dev_err(dev, "failed to parse memory region
> > %pOF: %d\n",
> > + it.node, err);
> > + continue;
> > + }
> > + }
> > +
> > + maps = of_get_property(it.node, "iommu-addresses", );
> > + if (maps) {
> > + const __be32 *end = maps + size / sizeof(__be32);
> > + struct device_node *np;
> > + unsigned int index = 0;
> > + u32 phandle;
> > + int na, ns;
> > +
> > + while (maps < end) {
> > + phys_addr_t start, end;
> > + size_t length;
> > +
> > + phandle = be32_to_cpup(maps++);
> > + np = of_find_node_by_phandle(phandle);
> > + na = of_n_addr_cells(np);
> > + ns = of_n_size_cells(np);
> > +
> > + start = of_translate_dma_address(np, maps);
> > + length = of_read_number(maps + na, ns);
>
> alternatively we could handle mappings/reservations with length 0 as
> error and skip them.
I
Re: [PATCH v5 2/5] iommu: Implement of_iommu_get_resv_regions()
On 2022-05-12 21:00:49 +0200, Thierry Reding wrote:
> 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.
>
> Signed-off-by: Thierry Reding
> ---
> Changes in v5:
> - update for new "iommu-addresses" device tree bindings
>
> Changes in v4:
> - fix build failure on !CONFIG_OF_ADDRESS
>
> 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 | 90
> include/linux/of_iommu.h | 8
> 2 files changed, 98 insertions(+)
>
> diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
> index 5696314ae69e..9e341b5e307f 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
>
> static int of_iommu_xlate(struct device *dev,
> @@ -172,3 +175,90 @@ 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)
> +{
> +#if IS_ENABLED(CONFIG_OF_ADDRESS)
> + struct of_phandle_iterator it;
> + int err;
> +
> + of_for_each_phandle(, err, dev->of_node, "memory-region", NULL, 0) {
> + struct iommu_resv_region *region;
> + struct resource res;
> + const __be32 *maps;
> + int size;
Adding 'if (!of_device_is_available(it.node)) continue;' here would help
backwards compatibility. My plan was to add the reserved regions with
"iommu-addresses" with all zero adresses and sizes with status =
"disabled" to the devicetree. A bootloader update is required to fill
those.
> +
> + memset(, 0, sizeof(res));
> +
> + /*
> + * The "reg" property is optional and can be omitted by
> reserved-memory regions
> + * that represent reservations in the IOVA space, which are
> regions that should
> + * not be mapped.
> + */
> + if (of_find_property(it.node, "reg", NULL)) {
> + err = of_address_to_resource(it.node, 0, );
> + if (err < 0) {
> + dev_err(dev, "failed to parse memory region
> %pOF: %d\n",
> + it.node, err);
> + continue;
> + }
> + }
> +
> + maps = of_get_property(it.node, "iommu-addresses", );
> + if (maps) {
> + const __be32 *end = maps + size / sizeof(__be32);
> + struct device_node *np;
> + unsigned int index = 0;
> + u32 phandle;
> + int na, ns;
> +
> + while (maps < end) {
> + phys_addr_t start, end;
> + size_t length;
> +
> + phandle = be32_to_cpup(maps++);
> + np = of_find_node_by_phandle(phandle);
> + na = of_n_addr_cells(np);
> + ns = of_n_size_cells(np);
> +
> + start = of_translate_dma_address(np, maps);
> + length = of_read_number(maps + na, ns);
alternatively we could handle mappings/reservations with length 0 as
error and skip them.
> + end = start + length - 1;
> +
> + if (np == dev->of_node) {
> + int prot = IOMMU_READ | IOMMU_WRITE;
> + enum iommu_resv_type type;
> +
> + /*
> + * IOMMU regions without an associated
> physical region
> + * cannot be mapped and are simply
>
[PATCH v5 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.
Signed-off-by: Thierry Reding
---
Changes in v5:
- update for new "iommu-addresses" device tree bindings
Changes in v4:
- fix build failure on !CONFIG_OF_ADDRESS
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 | 90
include/linux/of_iommu.h | 8
2 files changed, 98 insertions(+)
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 5696314ae69e..9e341b5e307f 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
static int of_iommu_xlate(struct device *dev,
@@ -172,3 +175,90 @@ 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)
+{
+#if IS_ENABLED(CONFIG_OF_ADDRESS)
+ struct of_phandle_iterator it;
+ int err;
+
+ of_for_each_phandle(, err, dev->of_node, "memory-region", NULL, 0) {
+ struct iommu_resv_region *region;
+ struct resource res;
+ const __be32 *maps;
+ int size;
+
+ memset(, 0, sizeof(res));
+
+ /*
+* The "reg" property is optional and can be omitted by
reserved-memory regions
+* that represent reservations in the IOVA space, which are
regions that should
+* not be mapped.
+*/
+ if (of_find_property(it.node, "reg", NULL)) {
+ err = of_address_to_resource(it.node, 0, );
+ if (err < 0) {
+ dev_err(dev, "failed to parse memory region
%pOF: %d\n",
+ it.node, err);
+ continue;
+ }
+ }
+
+ maps = of_get_property(it.node, "iommu-addresses", );
+ if (maps) {
+ const __be32 *end = maps + size / sizeof(__be32);
+ struct device_node *np;
+ unsigned int index = 0;
+ u32 phandle;
+ int na, ns;
+
+ while (maps < end) {
+ phys_addr_t start, end;
+ size_t length;
+
+ phandle = be32_to_cpup(maps++);
+ np = of_find_node_by_phandle(phandle);
+ na = of_n_addr_cells(np);
+ ns = of_n_size_cells(np);
+
+ start = of_translate_dma_address(np, maps);
+ length = of_read_number(maps + na, ns);
+ end = start + length - 1;
+
+ if (np == dev->of_node) {
+ int prot = IOMMU_READ | IOMMU_WRITE;
+ enum iommu_resv_type type;
+
+ /*
+* IOMMU regions without an associated
physical region
+* cannot be mapped and are simply
reservations.
+*/
+ if (res.end > res.start)
+ type =
IOMMU_RESV_DIRECT_RELAXABLE;
+ else
+ type = IOMMU_RESV_RESERVED;
+
+ region = iommu_alloc_resv_region(start,
length, prot, type);
+ if (region)
+ list_add_tail(>list,
list);
+ }
+
+
