ACPI/IORT: take _DMA methods into account for named components

Where IORT nodes for named components can describe simple DMA limits expressed as the number of address bits a device can drive, _DMA methods in AML can express more complex topologies, involving DMA translation in particular.

Currently, we only take this _DMA method into account if it appears on a ACPI device node describing a PCIe root complex, but it is perfectly acceptable to use them for named components as well, so let's ensure we take them into account in those cases too.

Note that such named components are expected to reside under a pseudo-bus node such as the ACPI0004 container device, which should be providing the _DMA method as well as a _CRS (as mandated by the ACPI spec). This is not enforced by the code however.

---
 drivers/acpi/arm64/iort.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

index ed3d2d1a7ae9..07eb78baf198 100644
@@ -1146,13 +1146,10 @@ void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)
 	else
 		size = 1ULL << 32;
 
-	if (dev_is_pci(dev)) {
-		ret = acpi_dma_get_range(dev, &dmaaddr, &offset, &size);
-		if (ret == -ENODEV)
-			ret = rc_dma_get_range(dev, &size);
-	} else {
-		ret = nc_dma_get_range(dev, &size);
-	}
+	ret = acpi_dma_get_range(dev, &dmaaddr, &offset, &size);
+	if (ret == -ENODEV)
+		ret = dev_is_pci(dev) ? rc_dma_get_range(dev, &size)
+				      : nc_dma_get_range(dev, &size);
 
 	if (!ret) {
 		/*

2.20.1

Applied to arm64 (for-next/acpi), thanks!

[1/1] ACPI/IORT: take _DMA methods into account for named components

      https://git.kernel.org/arm64/c/7fb89e1d44cb

Cheers,

Will

https://fixes.arm64.dev
https://next.arm64.dev