'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.
This keeps in sync with Linux kernel commit:
81db12ee15cb: of/address: Translate 'dma-ranges' for parent nodes missing 'dma-ranges'
Signed-off-by: Bin Meng bmeng.cn@gmail.com Reviewed-by: Simon Glass sjg@chromium.org
---
Changes in v2: - rebase on top of Dario's revert patch: http://patchwork.ozlabs.org/project/uboot/patch/20210425141746.19115-6-dario... - drop commit "of: addr: Abort address translation for parent nodes missing 'ranges'", as the revert patch restores the abort behavior
drivers/core/of_addr.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/core/of_addr.c b/drivers/core/of_addr.c index 9b77308182..a3af48fd88 100644 --- a/drivers/core/of_addr.c +++ b/drivers/core/of_addr.c @@ -192,9 +192,13 @@ static int of_translate_one(const struct device_node *parent, * * 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")) { debug("no ranges; cannot translate\n"); return 1; }