ACPI: Introduce DMA ranges parsing

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 <lorenzo.pieralisi@arm.com>
Tested-by: Nate Watterson <nwatters@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 68bc6be447fd..07eb963b5026 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);