'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 ---
drivers/core/of_addr.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/core/of_addr.c b/drivers/core/of_addr.c index 36cdfd3..b9abf90 100644 --- a/drivers/core/of_addr.c +++ b/drivers/core/of_addr.c @@ -174,12 +174,12 @@ static int of_translate_one(const struct device_node *parent, u64 offset = OF_BAD_ADDR;
ranges = of_get_property(parent, rprop, &rlen); - if (ranges == NULL) { + if (ranges == NULL && strcmp(rprop, "dma-ranges")) { debug("no ranges; cannot translate\n"); return 1; }
- if (rlen == 0) { + if (ranges == NULL || rlen == 0) { offset = of_read_number(addr, na); memset(addr, 0, pna * 4); debug("empty ranges; 1:1 translation\n");