Commit 5ac65e8c authored by Robin Murphy's avatar Robin Murphy Committed by Christoph Hellwig
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ACPI/IORT: Support address size limit for root complexes

IORT revision D allows PCI root complex nodes to specify a memory
address size limit equivalently to named components, to help describe
straightforward integrations which don't really warrant a full-blown
_DMA method. Now that our headers are up-to-date, plumb it in.

If both _DMA and an address size limit are present, we would always
expect the former to be a more specific subset of the latter (since it
makes little sense for a _DMA range to involve bits which IORT says
aren't wired up), thus we can save calculating an explicit intersection
of the two effective masks and simply use short-circuit logic instead.

Reviewed-by: default avatarHanjun Guo <>
Signed-off-by: Robin Murphy's avatarRobin Murphy <>
Acked-by: default avatarArd Biesheuvel <>
Acked-by: default avatarWill Deacon <>
Acked-by: Lorenzo Pieralisi's avatarLorenzo Pieralisi <>
Signed-off-by: default avatarChristoph Hellwig <>
parent a5516219
......@@ -947,6 +947,24 @@ static int nc_dma_get_range(struct device *dev, u64 *size)
return 0;
static int rc_dma_get_range(struct device *dev, u64 *size)
struct acpi_iort_node *node;
struct acpi_iort_root_complex *rc;
node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
iort_match_node_callback, dev);
if (!node || node->revision < 1)
return -ENODEV;
rc = (struct acpi_iort_root_complex *)node->node_data;
*size = rc->memory_address_limit >= 64 ? U64_MAX :
return 0;
* iort_dma_setup() - Set-up device DMA parameters.
......@@ -975,10 +993,13 @@ void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)
size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
if (dev_is_pci(dev))
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);
if (!ret) {
msb = fls64(dmaaddr + size - 1);
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