[PATCH 1/4] ACPI: Allow _DMA method in walk resources

[Lorenzo Pieralisi]

The _DMA object contains a resource template, this change adds support
for the walk resources function so that ACPI devices containing a _DMA
object can actually parse it to detect DMA ranges for the respective
bus.

Signed-off-by: Lorenzo Pieralisi <***@arm.com>
Cc: Robert Moore <***@intel.com>
Cc: Zhang Rui <***@intel.com>
Cc: "Rafael J. Wysocki" <***@rjwysocki.net>
---
drivers/acpi/acpica/rsxface.c | 7 ++++---
include/acpi/acnames.h | 1 +
2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/acpica/rsxface.c b/drivers/acpi/acpica/rsxface.c
index 59a4f9e..be65e65 100644
--- a/drivers/acpi/acpica/rsxface.c
+++ b/drivers/acpi/acpica/rsxface.c
@@ -615,7 +615,7 @@ ACPI_EXPORT_SYMBOL(acpi_walk_resource_buffer)
* device we are querying
* name - Method name of the resources we want.
* (METHOD_NAME__CRS, METHOD_NAME__PRS, or
- * METHOD_NAME__AEI)
+ * METHOD_NAME__AEI or METHOD_NAME__DMA)
* user_function - Called for each resource
* context - Passed to user_function
*
@@ -641,11 +641,12 @@ acpi_walk_resources(acpi_handle device_handle,
if (!device_handle || !user_function || !name ||
(!ACPI_COMPARE_NAME(name, METHOD_NAME__CRS) &&
!ACPI_COMPARE_NAME(name, METHOD_NAME__PRS) &&
- !ACPI_COMPARE_NAME(name, METHOD_NAME__AEI))) {
+ !ACPI_COMPARE_NAME(name, METHOD_NAME__AEI) &&
+ !ACPI_COMPARE_NAME(name, METHOD_NAME__DMA))) {
return_ACPI_STATUS(AE_BAD_PARAMETER);
}

- /* Get the _CRS/_PRS/_AEI resource list */
+ /* Get the _CRS/_PRS/_AEI/_DMA resource list */

buffer.length = ACPI_ALLOCATE_LOCAL_BUFFER;
status = acpi_rs_get_method_data(device_handle, name, &buffer);
diff --git a/include/acpi/acnames.h b/include/acpi/acnames.h
index b421584..d8dd3bf 100644
--- a/include/acpi/acnames.h
+++ b/include/acpi/acnames.h
@@ -54,6 +54,7 @@
#define METHOD_NAME__CLS "_CLS"
#define METHOD_NAME__CRS "_CRS"
#define METHOD_NAME__DDN "_DDN"
+#define METHOD_NAME__DMA "_DMA"
#define METHOD_NAME__HID "_HID"
#define METHOD_NAME__INI "_INI"
#define METHOD_NAME__PLD "_PLD"

[Lorenzo Pieralisi]

The function acpi_dev_get_resources() is completely generic and
can be used to parse resource objects that are not necessarily
coming from the _CRS method but also from other objects eg _DMA
that have the same _CRS resource format.

Create an acpi_dev_get_resources() helper, internal to the ACPI
resources parsing compilation unit, acpi_dev_get_resources_method(),
that takes a char* parameter to detect which ACPI method should be
called to retrieve the resources list and make acpi_dev_get_resources()
call it with a method name _CRS leaving the API behaviour unchanged.

Signed-off-by: Lorenzo Pieralisi <***@arm.com>
Cc: "Rafael J. Wysocki" <***@rjwysocki.net>
---
drivers/acpi/resource.c | 54 +++++++++++++++++++++++++++++--------------------
1 file changed, 32 insertions(+), 22 deletions(-)

diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index cd4c427..2b20a09 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -573,6 +573,36 @@ static acpi_status acpi_dev_process_resource(struct acpi_resource *ares,
return AE_OK;
}

+static
+int acpi_dev_get_resources_method(struct acpi_device *adev,
+ struct list_head *list,
+ int (*preproc)(struct acpi_resource *, void *),
+ void *preproc_data, char *method)
+{
+ struct res_proc_context c;
+ acpi_status status;
+
+ if (!adev || !adev->handle || !list_empty(list))
+ return -EINVAL;
+
+ if (!acpi_has_method(adev->handle, method))
+ return 0;
+
+ c.list = list;
+ c.preproc = preproc;
+ c.preproc_data = preproc_data;
+ c.count = 0;
+ c.error = 0;
+ status = acpi_walk_resources(adev->handle, method,
+ acpi_dev_process_resource, &c);
+ if (ACPI_FAILURE(status)) {
+ acpi_dev_free_resource_list(list);
+ return c.error ? c.error : -EIO;
+ }
+
+ return c.count;
+}
+
/**
* acpi_dev_get_resources - Get current resources of a device.
* @adev: ACPI device node to get the resources for.
@@ -601,28 +631,8 @@ int acpi_dev_get_resources(struct acpi_device *adev, struct list_head *list,
int (*preproc)(struct acpi_resource *, void *),
void *preproc_data)
{
- struct res_proc_context c;
- acpi_status status;
-
- if (!adev || !adev->handle || !list_empty(list))
- return -EINVAL;
-
- if (!acpi_has_method(adev->handle, METHOD_NAME__CRS))
- return 0;
-
- c.list = list;
- c.preproc = preproc;
- c.preproc_data = preproc_data;
- c.count = 0;
- c.error = 0;
- status = acpi_walk_resources(adev->handle, METHOD_NAME__CRS,
- acpi_dev_process_resource, &c);
- if (ACPI_FAILURE(status)) {
- acpi_dev_free_resource_list(list);
- return c.error ? c.error : -EIO;
- }
-
- return c.count;
+ return acpi_dev_get_resources_method(adev, list, preproc,
+ preproc_data, METHOD_NAME__CRS);
}
EXPORT_SYMBOL_GPL(acpi_dev_get_resources);

[Rafael J. Wysocki]

Post by Lorenzo Pieralisi
The function acpi_dev_get_resources() is completely generic and
can be used to parse resource objects that are not necessarily
coming from the _CRS method but also from other objects eg _DMA
that have the same _CRS resource format.
Create an acpi_dev_get_resources() helper, internal to the ACPI
resources parsing compilation unit, acpi_dev_get_resources_method(),
that takes a char* parameter to detect which ACPI method should be
called to retrieve the resources list and make acpi_dev_get_resources()
call it with a method name _CRS leaving the API behaviour unchanged.
---
drivers/acpi/resource.c | 54 +++++++++++++++++++++++++++++--------------------
1 file changed, 32 insertions(+), 22 deletions(-)
diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index cd4c427..2b20a09 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -573,6 +573,36 @@ static acpi_status acpi_dev_process_resource(struct acpi_resource *ares,
return AE_OK;
}
+static
+int acpi_dev_get_resources_method(struct acpi_device *adev,

Do not break lines like this, please.

It should be

static int acpi_dev_get...

Also I would call it differently, maybe simply __acpi_dev_get_resources()?

Post by Lorenzo Pieralisi
+ struct list_head *list,
+ int (*preproc)(struct acpi_resource *, void *),
+ void *preproc_data, char *method)

const char *method ?

Thanks,
Rafael

[Lorenzo Pieralisi]

Post by Rafael J. Wysocki

Post by Lorenzo Pieralisi
The function acpi_dev_get_resources() is completely generic and
can be used to parse resource objects that are not necessarily
coming from the _CRS method but also from other objects eg _DMA
that have the same _CRS resource format.
Create an acpi_dev_get_resources() helper, internal to the ACPI
resources parsing compilation unit, acpi_dev_get_resources_method(),
that takes a char* parameter to detect which ACPI method should be
called to retrieve the resources list and make acpi_dev_get_resources()
call it with a method name _CRS leaving the API behaviour unchanged.
---
drivers/acpi/resource.c | 54 +++++++++++++++++++++++++++++--------------------
1 file changed, 32 insertions(+), 22 deletions(-)
diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index cd4c427..2b20a09 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -573,6 +573,36 @@ static acpi_status acpi_dev_process_resource(struct acpi_resource *ares,
return AE_OK;
}
+static
+int acpi_dev_get_resources_method(struct acpi_device *adev,

Do not break lines like this, please.
It should be
static int acpi_dev_get...
Also I would call it differently, maybe simply __acpi_dev_get_resources()?

Ok, it was how I wanted to call it but was not sure you would be happy
with it, I will rename it.

Post by Rafael J. Wysocki

Post by Lorenzo Pieralisi
+ struct list_head *list,
+ int (*preproc)(struct acpi_resource *, void *),
+ void *preproc_data, char *method)

const char *method ?

Yes, will update.

Thanks !
Lorenzo

[Lorenzo Pieralisi]

Post by Rafael J. Wysocki

Post by Lorenzo Pieralisi
The function acpi_dev_get_resources() is completely generic and
can be used to parse resource objects that are not necessarily
coming from the _CRS method but also from other objects eg _DMA
that have the same _CRS resource format.
Create an acpi_dev_get_resources() helper, internal to the ACPI
resources parsing compilation unit, acpi_dev_get_resources_method(),
that takes a char* parameter to detect which ACPI method should be
called to retrieve the resources list and make acpi_dev_get_resources()
call it with a method name _CRS leaving the API behaviour unchanged.
---
drivers/acpi/resource.c | 54 +++++++++++++++++++++++++++++--------------------
1 file changed, 32 insertions(+), 22 deletions(-)
diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index cd4c427..2b20a09 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -573,6 +573,36 @@ static acpi_status acpi_dev_process_resource(struct acpi_resource *ares,
return AE_OK;
}
+static
+int acpi_dev_get_resources_method(struct acpi_device *adev,

Do not break lines like this, please.
It should be
static int acpi_dev_get...
Also I would call it differently, maybe simply __acpi_dev_get_resources()?

Post by Lorenzo Pieralisi
+ struct list_head *list,
+ int (*preproc)(struct acpi_resource *, void *),
+ void *preproc_data, char *method)

const char *method ?

drivers/acpi/resource.c: In function '__acpi_dev_get_resources':
drivers/acpi/resource.c:587:37: warning: passing argument 2 of
'acpi_has_method' discards 'const' qualifier from pointer target type
[-Wdiscarded-qualifiers]
if (!acpi_has_method(adev->handle, method))
^~~~~~
In file included from ./include/linux/acpi.h:44:0,
from drivers/acpi/resource.c:21:
./include/acpi/acpi_bus.h:55:6: note: expected 'char *'
but argument is of type 'const char *'
bool acpi_has_method(acpi_handle handle, char *name);

Same problem with acpi_walk_resources().

So either I fiddle (eg cast the const away) with the method string
in __acpi_dev_get_resources() or I can add an int/bool to detect
which method to use ( _CRS or _DMA) instead of passing a const char *.

Thanks,
Lorenzo

[Rafael J. Wysocki]

Post by Lorenzo Pieralisi

Post by Rafael J. Wysocki

Post by Lorenzo Pieralisi
The function acpi_dev_get_resources() is completely generic and
can be used to parse resource objects that are not necessarily
coming from the _CRS method but also from other objects eg _DMA
that have the same _CRS resource format.
Create an acpi_dev_get_resources() helper, internal to the ACPI
resources parsing compilation unit, acpi_dev_get_resources_method(),
that takes a char* parameter to detect which ACPI method should be
called to retrieve the resources list and make acpi_dev_get_resources()
call it with a method name _CRS leaving the API behaviour unchanged.
---
drivers/acpi/resource.c | 54 +++++++++++++++++++++++++++++--------------------
1 file changed, 32 insertions(+), 22 deletions(-)
diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index cd4c427..2b20a09 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -573,6 +573,36 @@ static acpi_status acpi_dev_process_resource(struct acpi_resource *ares,
return AE_OK;
}
+static
+int acpi_dev_get_resources_method(struct acpi_device *adev,

Do not break lines like this, please.
It should be
static int acpi_dev_get...
Also I would call it differently, maybe simply __acpi_dev_get_resources()?

Post by Lorenzo Pieralisi
+ struct list_head *list,
+ int (*preproc)(struct acpi_resource *, void *),
+ void *preproc_data, char *method)

const char *method ?

drivers/acpi/resource.c:587:37: warning: passing argument 2 of
'acpi_has_method' discards 'const' qualifier from pointer target type
[-Wdiscarded-qualifiers]
if (!acpi_has_method(adev->handle, method))
^~~~~~
In file included from ./include/linux/acpi.h:44:0,
./include/acpi/acpi_bus.h:55:6: note: expected 'char *'
but argument is of type 'const char *'
bool acpi_has_method(acpi_handle handle, char *name);
Same problem with acpi_walk_resources().
So either I fiddle (eg cast the const away) with the method string
in __acpi_dev_get_resources() or I can add an int/bool to detect
which method to use ( _CRS or _DMA) instead of passing a const char *.

No, that'd be overkill. Let's keep the (char *) in there.

Thanks,
Rafael

[Lorenzo Pieralisi]

Current ACPI DMA configuration set-up device DMA capabilities through
kernel defaults that do not take into account platform specific DMA
configurations reported by firmware.

By leveraging the ACPI acpi_dev_get_dma_resources() API, add code
in acpi_dma_configure() to retrieve the DMA regions to correctly
set-up devices DMA parameters.

Rework the ACPI IORT kernel API to make sure they can accommodate
the DMA set-up required by firmware. By making devices DMA set-up
ACPI IORT specific, the kernel is shielded from unwanted regressions
that could be triggered by parsing DMA resources on arches that were
previously ignoring them (ie x86/ia64), leaving kernel behaviour
unchanged on those arches.

Signed-off-by: Lorenzo Pieralisi <***@arm.com>
Cc: Will Deacon <***@arm.com>
Cc: Hanjun Guo <***@linaro.org>
Cc: Robin Murphy <***@arm.com>
Cc: "Rafael J. Wysocki" <***@rjwysocki.net>
---
drivers/acpi/arm64/iort.c | 27 +++++++++++++++++++++++++--
drivers/acpi/scan.c | 12 ++++--------
include/linux/acpi_iort.h | 5 +++--
3 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index a3215ee..9a7a65b 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -681,12 +681,17 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
}

/**
- * iort_set_dma_mask - Set-up dma mask for a device.
+ * iort_dma_setup() - Set-up device DMA parameters.
*
* @dev: device to configure
+ * @dma_addr: device DMA address result pointer
+ * @size: DMA range size result pointer
*/
-void iort_set_dma_mask(struct device *dev)
+void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)
{
+ u64 mask, dmaaddr = 0, size = 0, offset = 0;
+ int ret;
+
/*
* Set default coherent_dma_mask to 32 bit. Drivers are expected to
* setup the correct supported mask.
@@ -700,6 +705,24 @@ void iort_set_dma_mask(struct device *dev)
*/
if (!dev->dma_mask)
dev->dma_mask = &dev->coherent_dma_mask;
+
+ ret = acpi_dma_get_range(dev, &dmaaddr, &offset, &size);
+ if (ret < 0)
+ size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
+
+ mask = __roundup_pow_of_two(dmaaddr + size) - 1;
+ /*
+ * Limit coherent and dma mask based on size and default mask
+ * set by the driver.
+ */
+ dev->coherent_dma_mask = mask;
+ *dev->dma_mask = mask;
+
+ *dma_addr = dmaaddr;
+ *dma_size = size;
+
+ dev->dma_pfn_offset = PFN_DOWN(offset);
+ dev_dbg(dev, "dma_pfn_offset(%#08llx)\n", offset);
}

/**
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index eb493c2..15d0059 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1450,20 +1450,16 @@ int acpi_dma_get_range(struct device *dev, u64 *dma_addr, u64 *offset,
int acpi_dma_configure(struct device *dev, enum dev_dma_attr attr)
{
const struct iommu_ops *iommu;
- u64 size;
+ u64 dma_addr = 0, size = 0;

- iort_set_dma_mask(dev);
+ iort_dma_setup(dev, &dma_addr, &size);

iommu = iort_iommu_configure(dev);
if (IS_ERR(iommu) && PTR_ERR(iommu) == -EPROBE_DEFER)
return -EPROBE_DEFER;

- size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
- /*
- * Assume dma valid range starts at 0 and covers the whole
- * coherent_dma_mask.
- */
- arch_setup_dma_ops(dev, 0, size, iommu, attr == DEV_DMA_COHERENT);
+ arch_setup_dma_ops(dev, dma_addr, size,
+ iommu, attr == DEV_DMA_COHERENT);

return 0;
}
diff --git a/include/linux/acpi_iort.h b/include/linux/acpi_iort.h
index 8379d40..8d3f0bf 100644
--- a/include/linux/acpi_iort.h
+++ b/include/linux/acpi_iort.h
@@ -36,7 +36,7 @@ struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id);
void acpi_configure_pmsi_domain(struct device *dev);
int iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id);
/* IOMMU interface */
-void iort_set_dma_mask(struct device *dev);
+void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *size);
const struct iommu_ops *iort_iommu_configure(struct device *dev);
#else
static inline void acpi_iort_init(void) { }
@@ -47,7 +47,8 @@ static inline struct irq_domain *iort_get_device_domain(struct device *dev,
{ return NULL; }
static inline void acpi_configure_pmsi_domain(struct device *dev) { }
/* IOMMU interface */
-static inline void iort_set_dma_mask(struct device *dev) { }
+static inline void iort_dma_setup(struct device *dev, u64 *dma_addr,
+ u64 *size) { }
static inline
const struct iommu_ops *iort_iommu_configure(struct device *dev)
{ return NULL; }

[Lorenzo Pieralisi]

Some devices have limited addressing capabilities and cannot
reference the whole memory address space while carrying out DMA
operations (eg some devices with bus address bits range smaller than
system bus - which prevents them from using bus addresses that are
otherwise valid for the system).

The ACPI _DMA object allows bus devices to define the DMA window that is
actually addressable by devices that sit upstream the bus, therefore
providing a means to parse and initialize the devices DMA masks and
addressable DMA range size.

By relying on the generic ACPI kernel layer to retrieve and parse
resources, introduce ACPI core code to parse the _DMA object.

Signed-off-by: Lorenzo Pieralisi <***@arm.com>
Cc: Robin Murphy <***@arm.com>
Cc: "Rafael J. Wysocki" <***@rjwysocki.net>
---
drivers/acpi/resource.c | 35 +++++++++++++++++++++
drivers/acpi/scan.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++
include/acpi/acpi_bus.h | 2 ++
include/linux/acpi.h | 8 +++++
4 files changed, 128 insertions(+)

diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index 2b20a09..9602248 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -636,6 +636,41 @@ int acpi_dev_get_resources(struct acpi_device *adev, struct list_head *list,
}
EXPORT_SYMBOL_GPL(acpi_dev_get_resources);

+static int is_memory(struct acpi_resource *ares, void *not_used)
+{
+ struct resource_win win;
+ struct resource *res = &win.res;
+
+ memset(&win, 0, sizeof(win));
+
+ return !(acpi_dev_resource_memory(ares, res)
+ || acpi_dev_resource_address_space(ares, &win)
+ || acpi_dev_resource_ext_address_space(ares, &win));
+}
+
+/**
+ * acpi_dev_get_dma_resources - Get current DMA resources of a device.
+ * @adev: ACPI device node to get the resources for.
+ * @list: Head of the resultant list of resources (must be empty).
+ *
+ * Evaluate the _DMA method for the given device node and process its
+ * output.
+ *
+ * The resultant struct resource objects are put on the list pointed to
+ * by @list, that must be empty initially, as members of struct
+ * resource_entry objects. Callers of this routine should use
+ * %acpi_dev_free_resource_list() to free that list.
+ *
+ * The number of resources in the output list is returned on success,
+ * an error code reflecting the error condition is returned otherwise.
+ */
+int acpi_dev_get_dma_resources(struct acpi_device *adev, struct list_head *list)
+{
+ return acpi_dev_get_resources_method(adev, list, is_memory, NULL,
+ METHOD_NAME__DMA);
+}
+EXPORT_SYMBOL_GPL(acpi_dev_get_dma_resources);
+
/**
* acpi_dev_filter_resource_type - Filter ACPI resource according to resource
* types
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 3389729..eb493c2 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1360,6 +1360,89 @@ enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev)
}

/**
+ * acpi_dma_get_range() - Get device DMA parameters.
+ *
+ * @dev: device to configure
+ * @dma_addr: pointer device DMA address result
+ * @offset: pointer to the DMA offset result
+ * @size: pointer to DMA range size result
+ *
+ * Evaluate DMA regions and return respectively DMA region start, offset
+ * and size in dma_addr, offset and size on parsing success; it does not
+ * update the passed in values on failure.
+ *
+ * Return 0 on success, < 0 on failure.
+ */
+int acpi_dma_get_range(struct device *dev, u64 *dma_addr, u64 *offset,
+ u64 *size)
+{
+ struct acpi_device *adev;
+ LIST_HEAD(list);
+ struct resource_entry *rentry;
+ int ret;
+ struct device *dma_dev = dev;
+ struct acpi_buffer name_buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+ u64 dma_start = U64_MAX, dma_end = 0, dma_offset = 0;
+
+ /*
+ * Walk the device tree chasing an ACPI companion with a _DMA
+ * object while we go. Stop if we find a device with an ACPI
+ * companion containing a _DMA method.
+ */
+ do {
+ if (has_acpi_companion(dma_dev)) {
+ adev = ACPI_COMPANION(dma_dev);
+
+ if (acpi_has_method(adev->handle, METHOD_NAME__DMA))
+ break;
+ }
+ } while ((dma_dev = dma_dev->parent));
+
+ if (!dma_dev)
+ return -ENODEV;
+
+ if (!acpi_has_method(adev->handle, METHOD_NAME__CRS)) {
+ acpi_get_name(adev->handle, ACPI_FULL_PATHNAME, &name_buffer);
+ pr_warn(FW_BUG "%s: _DMA object only valid in object with valid _CRS\n",
+ (char *)name_buffer.pointer);
+ kfree(name_buffer.pointer);
+ return -EINVAL;
+ }
+
+ ret = acpi_dev_get_dma_resources(adev, &list);
+ if (ret > 0) {
+ list_for_each_entry(rentry, &list, node) {
+ if (dma_offset && rentry->offset != dma_offset) {
+ ret = -EINVAL;
+ pr_warn("Can't handle multiple windows with different offsets\n");
+ goto out;
+ }
+ dma_offset = rentry->offset;
+
+ /* Take lower and upper limits */
+ if (rentry->res->start < dma_start)
+ dma_start = rentry->res->start;
+ if (rentry->res->end > dma_end)
+ dma_end = rentry->res->end;
+ }
+
+ if (dma_start >= dma_end) {
+ ret = -EINVAL;
+ pr_warn("Invalid DMA regions configuration\n");
+ goto out;
+ }
+
+ *dma_addr = dma_start - dma_offset;
+ *size = dma_end - dma_start + 1;
+ *offset = dma_offset;
+ }
+ out:
+ acpi_dev_free_resource_list(&list);
+
+ return ret >= 0 ? 0 : ret;
+}
+
+/**
* acpi_dma_configure - Set-up DMA configuration for the device.
* @dev: The pointer to the device
* @attr: device dma attributes
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 68bc6be..07eb963 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -578,6 +578,8 @@ struct acpi_pci_root {

bool acpi_dma_supported(struct acpi_device *adev);
enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev);
+int acpi_dma_get_range(struct device *dev, u64 *dma_addr, u64 *offset,
+ u64 *size);
int acpi_dma_configure(struct device *dev, enum dev_dma_attr attr);
void acpi_dma_deconfigure(struct device *dev);

diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index c749eef..a5eaff9 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -427,6 +427,8 @@ void acpi_dev_free_resource_list(struct list_head *list);
int acpi_dev_get_resources(struct acpi_device *adev, struct list_head *list,
int (*preproc)(struct acpi_resource *, void *),
void *preproc_data);
+int acpi_dev_get_dma_resources(struct acpi_device *adev,
+ struct list_head *list);
int acpi_dev_filter_resource_type(struct acpi_resource *ares,
unsigned long types);

@@ -774,6 +776,12 @@ static inline enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev)
return DEV_DMA_NOT_SUPPORTED;
}

+static inline int acpi_dma_get_range(struct device *dev, u64 *dma_addr,
+ u64 *offset, u64 *size)
+{
+ return -ENODEV;
+}
+
static inline int acpi_dma_configure(struct device *dev,
enum dev_dma_attr attr)
{

[Rafael J. Wysocki]

Post by Lorenzo Pieralisi
Some devices have limited addressing capabilities and cannot
reference the whole memory address space while carrying out DMA
operations (eg some devices with bus address bits range smaller than
system bus - which prevents them from using bus addresses that are
otherwise valid for the system).
The ACPI _DMA object allows bus devices to define the DMA window that is
actually addressable by devices that sit upstream the bus, therefore
providing a means to parse and initialize the devices DMA masks and
addressable DMA range size.
By relying on the generic ACPI kernel layer to retrieve and parse
resources, introduce ACPI core code to parse the _DMA object.
---
drivers/acpi/resource.c | 35 +++++++++++++++++++++
drivers/acpi/scan.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++
include/acpi/acpi_bus.h | 2 ++
include/linux/acpi.h | 8 +++++
4 files changed, 128 insertions(+)
diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index 2b20a09..9602248 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -636,6 +636,41 @@ int acpi_dev_get_resources(struct acpi_device *adev, struct list_head *list,
}
EXPORT_SYMBOL_GPL(acpi_dev_get_resources);
+static int is_memory(struct acpi_resource *ares, void *not_used)
+{
+ struct resource_win win;
+ struct resource *res = &win.res;
+
+ memset(&win, 0, sizeof(win));
+
+ return !(acpi_dev_resource_memory(ares, res)
+ || acpi_dev_resource_address_space(ares, &win)
+ || acpi_dev_resource_ext_address_space(ares, &win));
+}
+
+/**
+ * acpi_dev_get_dma_resources - Get current DMA resources of a device.
+ *
+ * Evaluate the _DMA method for the given device node and process its
+ * output.
+ *
+ * The resultant struct resource objects are put on the list pointed to
+ * resource_entry objects. Callers of this routine should use
+ * %acpi_dev_free_resource_list() to free that list.
+ *
+ * The number of resources in the output list is returned on success,
+ * an error code reflecting the error condition is returned otherwise.
+ */
+int acpi_dev_get_dma_resources(struct acpi_device *adev, struct list_head *list)
+{
+ return acpi_dev_get_resources_method(adev, list, is_memory, NULL,
+ METHOD_NAME__DMA);
+}
+EXPORT_SYMBOL_GPL(acpi_dev_get_dma_resources);
+
/**
* acpi_dev_filter_resource_type - Filter ACPI resource according to resource
* types
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 3389729..eb493c2 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1360,6 +1360,89 @@ enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev)
}
/**
+ * acpi_dma_get_range() - Get device DMA parameters.
+ *
+ *
+ * Evaluate DMA regions and return respectively DMA region start, offset
+ * and size in dma_addr, offset and size on parsing success; it does not
+ * update the passed in values on failure.
+ *
+ * Return 0 on success, < 0 on failure.
+ */
+int acpi_dma_get_range(struct device *dev, u64 *dma_addr, u64 *offset,
+ u64 *size)
+{
+ struct acpi_device *adev;
+ LIST_HEAD(list);
+ struct resource_entry *rentry;
+ int ret;
+ struct device *dma_dev = dev;
+ struct acpi_buffer name_buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+ u64 dma_start = U64_MAX, dma_end = 0, dma_offset = 0;
+
+ /*
+ * Walk the device tree chasing an ACPI companion with a _DMA
+ * object while we go. Stop if we find a device with an ACPI
+ * companion containing a _DMA method.
+ */
+ do {
+ if (has_acpi_companion(dma_dev)) {
+ adev = ACPI_COMPANION(dma_dev);
+
+ if (acpi_has_method(adev->handle, METHOD_NAME__DMA))
+ break;

Why don't you do

adev = ACPI_COMPANION(dma_dev);
if (adev && acpi_has_method(adev->handle, METHOD_NAME__DMA))
break;

instead?

Post by Lorenzo Pieralisi
+ }
+ } while ((dma_dev = dma_dev->parent));

We had a rule to avoid things like this once and it wasn't a bad one. :-)

Why don't you just do

dma_dev = dma_dev->parent;
} while (dma_dev);

?

Post by Lorenzo Pieralisi
+
+ if (!dma_dev)
+ return -ENODEV;
+
+ if (!acpi_has_method(adev->handle, METHOD_NAME__CRS)) {
+ acpi_get_name(adev->handle, ACPI_FULL_PATHNAME, &name_buffer);
+ pr_warn(FW_BUG "%s: _DMA object only valid in object with valid _CRS\n",
+ (char *)name_buffer.pointer);
+ kfree(name_buffer.pointer);

We have acpi_handle_warn() and friends for stuff like that ...

Post by Lorenzo Pieralisi
+ return -EINVAL;
+ }
+
+ ret = acpi_dev_get_dma_resources(adev, &list);
+ if (ret > 0) {
+ list_for_each_entry(rentry, &list, node) {
+ if (dma_offset && rentry->offset != dma_offset) {
+ ret = -EINVAL;
+ pr_warn("Can't handle multiple windows with different offsets\n");
+ goto out;
+ }
+ dma_offset = rentry->offset;
+
+ /* Take lower and upper limits */
+ if (rentry->res->start < dma_start)
+ dma_start = rentry->res->start;
+ if (rentry->res->end > dma_end)
+ dma_end = rentry->res->end;
+ }
+
+ if (dma_start >= dma_end) {
+ ret = -EINVAL;
+ pr_warn("Invalid DMA regions configuration\n");

dev_warn()?

And why _warn() and not _info()?

Post by Lorenzo Pieralisi
+ goto out;
+ }
+
+ *dma_addr = dma_start - dma_offset;
+ *size = dma_end - dma_start + 1;
+ *offset = dma_offset;
+ }
+ acpi_dev_free_resource_list(&list);
+
+ return ret >= 0 ? 0 : ret;
+}

Thanks,
Rafael

[Lorenzo Pieralisi]

On Sat, Jul 22, 2017 at 12:15:42AM +0200, Rafael J. Wysocki wrote:

[...]

Post by Rafael J. Wysocki

Post by Lorenzo Pieralisi
+ * acpi_dma_get_range() - Get device DMA parameters.
+ *
+ *
+ * Evaluate DMA regions and return respectively DMA region start, offset
+ * and size in dma_addr, offset and size on parsing success; it does not
+ * update the passed in values on failure.
+ *
+ * Return 0 on success, < 0 on failure.
+ */
+int acpi_dma_get_range(struct device *dev, u64 *dma_addr, u64 *offset,
+ u64 *size)
+{
+ struct acpi_device *adev;
+ LIST_HEAD(list);
+ struct resource_entry *rentry;
+ int ret;
+ struct device *dma_dev = dev;
+ struct acpi_buffer name_buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+ u64 dma_start = U64_MAX, dma_end = 0, dma_offset = 0;
+
+ /*
+ * Walk the device tree chasing an ACPI companion with a _DMA
+ * object while we go. Stop if we find a device with an ACPI
+ * companion containing a _DMA method.
+ */
+ do {
+ if (has_acpi_companion(dma_dev)) {
+ adev = ACPI_COMPANION(dma_dev);
+
+ if (acpi_has_method(adev->handle, METHOD_NAME__DMA))
+ break;

Why don't you do
adev = ACPI_COMPANION(dma_dev);
if (adev && acpi_has_method(adev->handle, METHOD_NAME__DMA))
break;
instead?

Yes, it is better.

Post by Rafael J. Wysocki

Post by Lorenzo Pieralisi
+ }
+ } while ((dma_dev = dma_dev->parent));

We had a rule to avoid things like this once and it wasn't a bad one. :-)
Why don't you just do
dma_dev = dma_dev->parent;
} while (dma_dev);
?

Yes I should have done that in the first place, will update.

Post by Rafael J. Wysocki

Post by Lorenzo Pieralisi
+
+ if (!dma_dev)
+ return -ENODEV;
+
+ if (!acpi_has_method(adev->handle, METHOD_NAME__CRS)) {
+ acpi_get_name(adev->handle, ACPI_FULL_PATHNAME, &name_buffer);
+ pr_warn(FW_BUG "%s: _DMA object only valid in object with valid _CRS\n",
+ (char *)name_buffer.pointer);
+ kfree(name_buffer.pointer);

We have acpi_handle_warn() and friends for stuff like that ...

I will update to it.

Post by Rafael J. Wysocki

Post by Lorenzo Pieralisi
+ return -EINVAL;
+ }
+
+ ret = acpi_dev_get_dma_resources(adev, &list);
+ if (ret > 0) {
+ list_for_each_entry(rentry, &list, node) {
+ if (dma_offset && rentry->offset != dma_offset) {
+ ret = -EINVAL;
+ pr_warn("Can't handle multiple windows with different offsets\n");
+ goto out;
+ }
+ dma_offset = rentry->offset;
+
+ /* Take lower and upper limits */
+ if (rentry->res->start < dma_start)
+ dma_start = rentry->res->start;
+ if (rentry->res->end > dma_end)
+ dma_end = rentry->res->end;
+ }
+
+ if (dma_start >= dma_end) {
+ ret = -EINVAL;
+ pr_warn("Invalid DMA regions configuration\n");

dev_warn()?
And why _warn() and not _info()?

Mmm..ok for the dev_ prefix - basically this would be a FW_BUG (I think
this specific error condition is overkill TBH, the ACPI resource
validation code should catch it before we even get here) not sure
about downgrading it to _info() though, I would leave it at this
loglevel - in particular in the offset check above:

if (dma_offset && rentry->offset != dma_offset) {
ret = -EINVAL;
pr_warn("Can't handle multiple windows with different offsets\n");
goto out;
}

Thanks,
Lorenzo

[Rafael J. Wysocki]

On Mon, Jul 24, 2017 at 12:40 PM, Lorenzo Pieralisi
[cut]

Post by Lorenzo Pieralisi

Post by Rafael J. Wysocki

+ return -EINVAL;
+ }
+
+ ret = acpi_dev_get_dma_resources(adev, &list);
+ if (ret > 0) {
+ list_for_each_entry(rentry, &list, node) {
+ if (dma_offset && rentry->offset != dma_offset) {
+ ret = -EINVAL;
+ pr_warn("Can't handle multiple windows with different offsets\n");
+ goto out;
+ }
+ dma_offset = rentry->offset;
+
+ /* Take lower and upper limits */
+ if (rentry->res->start < dma_start)
+ dma_start = rentry->res->start;
+ if (rentry->res->end > dma_end)
+ dma_end = rentry->res->end;
+ }
+
+ if (dma_start >= dma_end) {
+ ret = -EINVAL;
+ pr_warn("Invalid DMA regions configuration\n");

dev_warn()?
And why _warn() and not _info()?

Mmm..ok for the dev_ prefix - basically this would be a FW_BUG (I think
this specific error condition is overkill TBH, the ACPI resource
validation code should catch it before we even get here) not sure
about downgrading it to _info() though, I would leave it at this
if (dma_offset && rentry->offset != dma_offset) {
ret = -EINVAL;
pr_warn("Can't handle multiple windows with different offsets\n");
goto out;
}

Well, so the "why" question above still has no answer ...

[Lorenzo Pieralisi]

Post by Rafael J. Wysocki
On Mon, Jul 24, 2017 at 12:40 PM, Lorenzo Pieralisi
[cut]

Post by Lorenzo Pieralisi

Post by Rafael J. Wysocki

+ return -EINVAL;
+ }
+
+ ret = acpi_dev_get_dma_resources(adev, &list);
+ if (ret > 0) {
+ list_for_each_entry(rentry, &list, node) {
+ if (dma_offset && rentry->offset != dma_offset) {
+ ret = -EINVAL;
+ pr_warn("Can't handle multiple windows with different offsets\n");
+ goto out;
+ }
+ dma_offset = rentry->offset;
+
+ /* Take lower and upper limits */
+ if (rentry->res->start < dma_start)
+ dma_start = rentry->res->start;
+ if (rentry->res->end > dma_end)
+ dma_end = rentry->res->end;
+ }
+
+ if (dma_start >= dma_end) {
+ ret = -EINVAL;
+ pr_warn("Invalid DMA regions configuration\n");

dev_warn()?
And why _warn() and not _info()?

Mmm..ok for the dev_ prefix - basically this would be a FW_BUG (I think
this specific error condition is overkill TBH, the ACPI resource
validation code should catch it before we even get here) not sure
about downgrading it to _info() though, I would leave it at this
if (dma_offset && rentry->offset != dma_offset) {
ret = -EINVAL;
pr_warn("Can't handle multiple windows with different offsets\n");
goto out;
}

Well, so the "why" question above still has no answer ...

It is a firmware misconfiguration, we end up dismissing firmware
information and use the device with default/possibly misconfigured
DMA windows (ie offset == 0) for that platform, that's the reason
why I thought it would deserve a _warn rather than _info loglevel.

Thanks,
Lorenzo

[Rafael J. Wysocki]

Post by Lorenzo Pieralisi

Post by Rafael J. Wysocki
On Mon, Jul 24, 2017 at 12:40 PM, Lorenzo Pieralisi
[cut]

Post by Lorenzo Pieralisi

Post by Rafael J. Wysocki

+ return -EINVAL;
+ }
+
+ ret = acpi_dev_get_dma_resources(adev, &list);
+ if (ret > 0) {
+ list_for_each_entry(rentry, &list, node) {
+ if (dma_offset && rentry->offset != dma_offset) {
+ ret = -EINVAL;
+ pr_warn("Can't handle multiple windows with different offsets\n");
+ goto out;
+ }
+ dma_offset = rentry->offset;
+
+ /* Take lower and upper limits */
+ if (rentry->res->start < dma_start)
+ dma_start = rentry->res->start;
+ if (rentry->res->end > dma_end)
+ dma_end = rentry->res->end;
+ }
+
+ if (dma_start >= dma_end) {
+ ret = -EINVAL;
+ pr_warn("Invalid DMA regions configuration\n");

dev_warn()?
And why _warn() and not _info()?

Mmm..ok for the dev_ prefix - basically this would be a FW_BUG (I think
this specific error condition is overkill TBH, the ACPI resource
validation code should catch it before we even get here) not sure
about downgrading it to _info() though, I would leave it at this
if (dma_offset && rentry->offset != dma_offset) {
ret = -EINVAL;
pr_warn("Can't handle multiple windows with different offsets\n");
goto out;
}

Well, so the "why" question above still has no answer ...

It is a firmware misconfiguration, we end up dismissing firmware
information and use the device with default/possibly misconfigured
DMA windows (ie offset == 0) for that platform, that's the reason
why I thought it would deserve a _warn rather than _info loglevel.

Well, _warn only makes it slightly more visible for people with somewhat
unusual logging configurations, but fair enough.

Thanks,
Rafael

[Moore, Robert]

I think we can take this as-is into ACPICA.
Bob

-----Original Message-----
Sent: Thursday, July 20, 2017 7:45 AM
Subject: [PATCH 1/4] ACPI: Allow _DMA method in walk resources
The _DMA object contains a resource template, this change adds support
for the walk resources function so that ACPI devices containing a _DMA
object can actually parse it to detect DMA ranges for the respective
bus.
---
drivers/acpi/acpica/rsxface.c | 7 ++++---
include/acpi/acnames.h | 1 +
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/acpi/acpica/rsxface.c
b/drivers/acpi/acpica/rsxface.c index 59a4f9e..be65e65 100644
--- a/drivers/acpi/acpica/rsxface.c
+++ b/drivers/acpi/acpica/rsxface.c
@@ -615,7 +615,7 @@ ACPI_EXPORT_SYMBOL(acpi_walk_resource_buffer)
* device we are querying
* name - Method name of the resources we want.
* (METHOD_NAME__CRS, METHOD_NAME__PRS, or
- * METHOD_NAME__AEI)
+ * METHOD_NAME__AEI or METHOD_NAME__DMA)
* user_function - Called for each resource
* context - Passed to user_function
*
@@ -641,11 +641,12 @@ acpi_walk_resources(acpi_handle device_handle,
if (!device_handle || !user_function || !name ||
(!ACPI_COMPARE_NAME(name, METHOD_NAME__CRS) &&
!ACPI_COMPARE_NAME(name, METHOD_NAME__PRS) &&
- !ACPI_COMPARE_NAME(name, METHOD_NAME__AEI))) {
+ !ACPI_COMPARE_NAME(name, METHOD_NAME__AEI) &&
+ !ACPI_COMPARE_NAME(name, METHOD_NAME__DMA))) {
return_ACPI_STATUS(AE_BAD_PARAMETER);
}
- /* Get the _CRS/_PRS/_AEI resource list */
+ /* Get the _CRS/_PRS/_AEI/_DMA resource list */
buffer.length = ACPI_ALLOCATE_LOCAL_BUFFER;
status = acpi_rs_get_method_data(device_handle, name, &buffer);
diff --git a/include/acpi/acnames.h b/include/acpi/acnames.h index
b421584..d8dd3bf 100644
--- a/include/acpi/acnames.h
+++ b/include/acpi/acnames.h
@@ -54,6 +54,7 @@
#define METHOD_NAME__CLS "_CLS"
#define METHOD_NAME__CRS "_CRS"
#define METHOD_NAME__DDN "_DDN"
+#define METHOD_NAME__DMA "_DMA"
#define METHOD_NAME__HID "_HID"
#define METHOD_NAME__INI "_INI"
#define METHOD_NAME__PLD "_PLD"
--
2.10.0

[Moore, Robert]

Could you post this as a pull request on our github?

https://github.com/acpica/acpica

-----Original Message-----
From: Moore, Robert
Sent: Thursday, July 20, 2017 8:49 AM
Subject: RE: [PATCH 1/4] ACPI: Allow _DMA method in walk resources
I think we can take this as-is into ACPICA.
Bob

-----Original Message-----
Sent: Thursday, July 20, 2017 7:45 AM
Subject: [PATCH 1/4] ACPI: Allow _DMA method in walk resources
The _DMA object contains a resource template, this change adds support
for the walk resources function so that ACPI devices containing a _DMA
object can actually parse it to detect DMA ranges for the respective
bus.
---
drivers/acpi/acpica/rsxface.c | 7 ++++---
include/acpi/acnames.h | 1 +
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/acpi/acpica/rsxface.c
b/drivers/acpi/acpica/rsxface.c index 59a4f9e..be65e65 100644
--- a/drivers/acpi/acpica/rsxface.c
+++ b/drivers/acpi/acpica/rsxface.c
@@ -615,7 +615,7 @@ ACPI_EXPORT_SYMBOL(acpi_walk_resource_buffer)
* device we are querying
* name - Method name of the resources we

want.

* (METHOD_NAME__CRS,

METHOD_NAME__PRS,

or
- * METHOD_NAME__AEI)
+ * METHOD_NAME__AEI or

METHOD_NAME__DMA)

* user_function - Called for each resource
* context - Passed to user_function
*
@@ -641,11 +641,12 @@ acpi_walk_resources(acpi_handle device_handle,
if (!device_handle || !user_function || !name ||
(!ACPI_COMPARE_NAME(name, METHOD_NAME__CRS) &&
!ACPI_COMPARE_NAME(name, METHOD_NAME__PRS) &&
- !ACPI_COMPARE_NAME(name, METHOD_NAME__AEI))) {
+ !ACPI_COMPARE_NAME(name, METHOD_NAME__AEI) &&
+ !ACPI_COMPARE_NAME(name, METHOD_NAME__DMA))) {
return_ACPI_STATUS(AE_BAD_PARAMETER);
}
- /* Get the _CRS/_PRS/_AEI resource list */
+ /* Get the _CRS/_PRS/_AEI/_DMA resource list */
buffer.length = ACPI_ALLOCATE_LOCAL_BUFFER;
status = acpi_rs_get_method_data(device_handle, name, &buffer);

diff

--git a/include/acpi/acnames.h b/include/acpi/acnames.h index
b421584..d8dd3bf 100644
--- a/include/acpi/acnames.h
+++ b/include/acpi/acnames.h
@@ -54,6 +54,7 @@
#define METHOD_NAME__CLS "_CLS"
#define METHOD_NAME__CRS "_CRS"
#define METHOD_NAME__DDN "_DDN"
+#define METHOD_NAME__DMA "_DMA"
#define METHOD_NAME__HID "_HID"
#define METHOD_NAME__INI "_INI"
#define METHOD_NAME__PLD "_PLD"
--
2.10.0

[Lorenzo Pieralisi]

Post by Moore, Robert
Could you post this as a pull request on our github?
https://github.com/acpica/acpica

Sure, will do, thanks !

Lorenzo

Post by Moore, Robert

-----Original Message-----
From: Moore, Robert
Sent: Thursday, July 20, 2017 8:49 AM
Subject: RE: [PATCH 1/4] ACPI: Allow _DMA method in walk resources
I think we can take this as-is into ACPICA.
Bob

-----Original Message-----
Sent: Thursday, July 20, 2017 7:45 AM
Subject: [PATCH 1/4] ACPI: Allow _DMA method in walk resources
The _DMA object contains a resource template, this change adds support
for the walk resources function so that ACPI devices containing a _DMA
object can actually parse it to detect DMA ranges for the respective
bus.
---
drivers/acpi/acpica/rsxface.c | 7 ++++---
include/acpi/acnames.h | 1 +
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/acpi/acpica/rsxface.c
b/drivers/acpi/acpica/rsxface.c index 59a4f9e..be65e65 100644
--- a/drivers/acpi/acpica/rsxface.c
+++ b/drivers/acpi/acpica/rsxface.c
@@ -615,7 +615,7 @@ ACPI_EXPORT_SYMBOL(acpi_walk_resource_buffer)
* device we are querying
* name - Method name of the resources we

want.

* (METHOD_NAME__CRS,

METHOD_NAME__PRS,

or
- * METHOD_NAME__AEI)
+ * METHOD_NAME__AEI or

METHOD_NAME__DMA)

* user_function - Called for each resource
* context - Passed to user_function
*
@@ -641,11 +641,12 @@ acpi_walk_resources(acpi_handle device_handle,
if (!device_handle || !user_function || !name ||
(!ACPI_COMPARE_NAME(name, METHOD_NAME__CRS) &&
!ACPI_COMPARE_NAME(name, METHOD_NAME__PRS) &&
- !ACPI_COMPARE_NAME(name, METHOD_NAME__AEI))) {
+ !ACPI_COMPARE_NAME(name, METHOD_NAME__AEI) &&
+ !ACPI_COMPARE_NAME(name, METHOD_NAME__DMA))) {
return_ACPI_STATUS(AE_BAD_PARAMETER);
}
- /* Get the _CRS/_PRS/_AEI resource list */
+ /* Get the _CRS/_PRS/_AEI/_DMA resource list */
buffer.length = ACPI_ALLOCATE_LOCAL_BUFFER;
status = acpi_rs_get_method_data(device_handle, name, &buffer);

diff

--git a/include/acpi/acnames.h b/include/acpi/acnames.h index
b421584..d8dd3bf 100644
--- a/include/acpi/acnames.h
+++ b/include/acpi/acnames.h
@@ -54,6 +54,7 @@
#define METHOD_NAME__CLS "_CLS"
#define METHOD_NAME__CRS "_CRS"
#define METHOD_NAME__DDN "_DDN"
+#define METHOD_NAME__DMA "_DMA"
#define METHOD_NAME__HID "_HID"
#define METHOD_NAME__INI "_INI"
#define METHOD_NAME__PLD "_PLD"
--
2.10.0