A missing or empty dma-ranges in a DT node implies a 1:1 mapping for dma translations. In this specific case, the current behaviour is to zero out the entire specifier so that the translation could be carried on as an offset from zero. This includes address specifier that has flags (e.g. PCI ranges).
Once the flags portion has been zeroed, the translation chain is broken since the mapping functions will check the upcoming address specifier against mismatching flags, always failing the 1:1 mapping and its entire purpose of always succeeding.
Set to zero only the address portion while passing the flags through.
Fixes: dbbdee94734b ("of/address: Merge all of the bus translation code") Cc: stable@vger.kernel.org Signed-off-by: Andrea della Porta andrea.porta@suse.com Tested-by: Herve Codina herve.codina@bootlin.com --- drivers/of/address.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/of/address.c b/drivers/of/address.c index 286f0c161e33..b3479586bd4d 100644 --- a/drivers/of/address.c +++ b/drivers/of/address.c @@ -455,7 +455,8 @@ static int of_translate_one(struct device_node *parent, struct of_bus *bus, } if (ranges == NULL || rlen == 0) { offset = of_read_number(addr, na); - memset(addr, 0, pna * 4); + /* set address to zero, pass flags through */ + memset(addr + pbus->flag_cells, 0, (pna - pbus->flag_cells) * 4); pr_debug("empty ranges; 1:1 translation\n"); goto finish; }