| Message ID | 3029857353c9499659369c1540ba887d7860670f.1730123575.git.andrea.porta@suse.com |
|---|---|
| State | New |
| Headers | show |
| Series | Add support for RaspberryPi RP1 PCI device using a DT overlay | expand |
Hi Andrea, On Mon, 28 Oct 2024 15:07:23 +0100 Andrea della Porta <andrea.porta@suse.com> wrote: > 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. > > Signed-off-by: Andrea della Porta <andrea.porta@suse.com> Tested ok with my LAN966x PCI device. Tested-by: Herve Codina <herve.codina@bootlin.com> Best regards, Hervé
diff --git a/drivers/of/address.c b/drivers/of/address.c index 286f0c161e33..72b6accff21c 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); + /* copy the address while preserving the flags */ + memset(addr + pbus->flag_cells, 0, (pna - pbus->flag_cells) * 4); pr_debug("empty ranges; 1:1 translation\n"); goto finish; }
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. Signed-off-by: Andrea della Porta <andrea.porta@suse.com> --- drivers/of/address.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)