[PATCH v2] MTD: lantiq: handle NO_XIP on cfi0001 flash

[Jonas Gorski]

Hi,

On 6 June 2016 at 22:35, Hauke Mehrtens <hauke at hauke-m.de> wrote:
> From: John Crispin <john at phrozen.org>
>
> This uses the same device tree attribute as physmap_of.c
>
> Signed-off-by: John Crispin <john at phrozen.org>
> Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
> ---
>  drivers/mtd/maps/lantiq-flash.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/maps/lantiq-flash.c b/drivers/mtd/maps/lantiq-flash.c
> index c8febb3..88fc6d9 100644
> --- a/drivers/mtd/maps/lantiq-flash.c
> +++ b/drivers/mtd/maps/lantiq-flash.c
> @@ -137,7 +137,11 @@ ltq_mtd_probe(struct platform_device *pdev)
>         if (!ltq_mtd->map)
>                 return -ENOMEM;
>
> -       ltq_mtd->map->phys = ltq_mtd->res->start;
> +       if (of_find_property(pdev->dev.of_node, "no-unaligned-direct-access",
> +                            NULL))
> +               ltq_mtd->map->phys = NO_XIP;

This does not what you think it does; i.e. preventing unaligned io
memory accesses. All it's used for is in two drivers
(cfi_cmdset_0001.c, lpddr_cmds.c) as a check whether to populate
_point/_unpoint. But it does not prevent the map_read/map_write
accessors from doing memcpy_{from,to}_io() with unaligned addresses,
which at least on MIPS results in unaligned accesses with LWL/LWR.
Which is what I assume you want to prevent.


Regards
Jonas