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of/address: Translate 'dma-ranges' for parent nodes missing 'dma-ranges'

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'dma-ranges' frequently exists without parent nodes having 'dma-ranges'.
While this is an error for 'ranges', this is fine because DMA capable
devices always have a translatable DMA address. Also, with no
'dma-ranges' at all, the assumption is that DMA addresses are 1:1 with
no restrictions unless perhaps the device itself has implicit
restrictions.

Cc: Robin Murphy <robin.murphy@arm.com>
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Rob Herring <robh@kernel.org>
This commit is contained in:
Rob Herring 2019-09-04 11:43:30 +01:00
parent 04db93a95a
commit 81db12ee15
1 changed files with 5 additions and 1 deletions
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6
drivers/of/address.c
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@ -519,9 +519,13 @@ static int of_translate_one(struct device_node *parent, struct of_bus *bus,
*
* As far as we know, this damage only exists on Apple machines, so
* This code is only enabled on powerpc. --gcl
*
* This quirk also applies for 'dma-ranges' which frequently exist in
* child nodes without 'dma-ranges' in the parent nodes. --RobH
*/
ranges = of_get_property(parent, rprop, &rlen);
if (ranges == NULL && !of_empty_ranges_quirk(parent)) {
if (ranges == NULL && !of_empty_ranges_quirk(parent) &&
strcmp(rprop, "dma-ranges")) {
pr_debug("no ranges; cannot translate\n");
return 1;
}