The memory_address_limit field present in IORT named component nodes
describes the effective number of address bits that a device can use
when accessing memory. Because this information has value when creating
or validating device dma_masks, the aforementioned accessor function is
introduced.
Signed-off-by: Nate Watterson <nwatters@xxxxxxxxxxxxxx>
---
drivers/acpi/arm64/iort.c | 25 +++++++++++++++++++++++++
include/linux/acpi_iort.h | 3 +++
2 files changed, 28 insertions(+)
diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index e0d2e6e..cd5d5f4 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -569,6 +569,31 @@ void iort_set_dma_mask(struct device *dev)
}
/**
+ * iort_get_memory_address_limit - If a named component node exists in the IORT
+ * for a device, get the number of address bits
+ * that the device can effectively use when
+ * accessing memory.
+ *
+ * @dev: The device
+ *
+ * Returns: ENOENT when no corresponding named component node found for dev
+ * Named component memory_address_limit field otherwise
+ */
+int iort_get_memory_address_limit(struct device *dev)
+{
+ struct acpi_iort_node *node;
+ struct acpi_iort_named_component *ncomp;
+
+ node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT,
+ iort_match_node_callback, dev);
+ if (!node)
+ return -ENOENT;
+
+ ncomp = (struct acpi_iort_named_component *)node->node_data;
+ return ncomp->memory_address_limit;
+}
+
+/**
* iort_iommu_configure - Set-up IOMMU configuration for a device.
*
* @dev: device to configure
diff --git a/include/linux/acpi_iort.h b/include/linux/acpi_iort.h
index 77e0809..677b9c4 100644
--- a/include/linux/acpi_iort.h
+++ b/include/linux/acpi_iort.h
@@ -36,6 +36,7 @@
struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id);
/* IOMMU interface */
void iort_set_dma_mask(struct device *dev);
+int iort_get_memory_address_limit(struct device *dev);
const struct iommu_ops *iort_iommu_configure(struct device *dev);
#else
static inline void acpi_iort_init(void) { }
@@ -47,6 +48,8 @@ static inline struct irq_domain *iort_get_device_domain(struct device *dev,
{ return NULL; }
/* IOMMU interface */
static inline void iort_set_dma_mask(struct device *dev) { }
+static inline int iort_get_memory_address_limit(struct device *dev)
+{ return -ENOENT; }
static inline
const struct iommu_ops *iort_iommu_configure(struct device *dev)
{ return NULL; }
--
Qualcomm Datacenter Technologies, Inc. on behalf of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux
Foundation Collaborative Project.
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