Commit 81db12ee authored Sep 04, 2019 by Rob Herring

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



'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>

parent 04db93a9

drivers/of/address.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -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;
		}

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