of: addr: 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.

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>

diff --git a/drivers/core/of_addr.c b/drivers/core/of_addr.c
index 9b77308182d8daf78e082a75910b8c0dd321a46c..a3af48fd885416262af2971323cca9825363af2a 100644 (file)
--- 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;
        }