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Re: [PATCH 03/10] iommu/ipmmu-vmsa: Teach xlate() to skip disabled iommus

From Geert Uytterhoeven <geert@linux-m68k.org>
Newsgroups linux.kernel
Subject Re: [PATCH 03/10] iommu/ipmmu-vmsa: Teach xlate() to skip disabled iommus
Date 2016-03-18 10:50 +0100
Message-ID <rdZcB-3MQ-3@gated-at.bofh.it> (permalink)
References <rdIY9-1i1-5@gated-at.bofh.it> <rdIYc-1i1-45@gated-at.bofh.it>
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On Thu, Mar 17, 2016 at 5:29 PM, Magnus Damm <magnus.damm@gmail.com> wrote:
> From: Magnus Damm <damm+renesas@opensource.se>
>
> Right now the ->xlate() call gets invoked even though
> the iommu device has status = "disabled" in DT, so
> make sure we skip over disabled devices.
>
> In my mind it would make sense to have this at some
> shared level, but I guess some users may want to
> configure the iommu regardless of DT state.
>
> Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
> ---
>
>  drivers/iommu/ipmmu-vmsa.c |    8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> --- 0017/drivers/iommu/ipmmu-vmsa.c
> +++ work/drivers/iommu/ipmmu-vmsa.c     2016-03-18 00:16:51.200513000 +0900
> @@ -890,7 +890,13 @@ static struct iommu_group *ipmmu_device_
>  static int ipmmu_of_xlate_dma(struct device *dev,
>                               struct of_phandle_args *spec)
>  {
> -       /* dummy callback to satisfy of_iommu_configure() */
> +       /* If the IPMMU device is disabled in DT then return error
> +        * to make sure the of_iommu code does not install ops
> +        * even though the iommu device is disabled
> +        */
> +       if (!of_device_is_available(spec->np))
> +               return -ENODEV;
> +
>         return 0;

I think this should be handled in drivers/iommu/of_iommu.c:of_iommu_init()
instead, cfr. commit 3e5dd6f6e690048d ("clk: Ignore disabled DT clock
providers").

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

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Thread

[PATCH 00/10] iommu/ipmmu-vmsa: Initial r8a7795 support Magnus Damm <magnus.damm@gmail.com> - 2016-03-17 17:30 +0100
  [PATCH 09/10] iommu/ipmmu-vmsa: Allow two bit SL0 Magnus Damm <magnus.damm@gmail.com> - 2016-03-17 17:30 +0100
  [PATCH 06/10] iommu/ipmmu-vmsa: Add optional root device feature Magnus Damm <magnus.damm@gmail.com> - 2016-03-17 17:30 +0100
  [PATCH 05/10] iommu/ipmmu-vmsa: Introduce features, break out alias Magnus Damm <magnus.damm@gmail.com> - 2016-03-17 17:30 +0100
  [PATCH 10/10] iommu/ipmmu-vmsa: Hook up r8a7795 DT matching code Magnus Damm <magnus.damm@gmail.com> - 2016-03-17 17:30 +0100
  [PATCH 07/10] iommu/ipmmu-vmsa: Write IMCTR twice Magnus Damm <magnus.damm@gmail.com> - 2016-03-17 17:30 +0100
  [PATCH 01/10] iommu/ipmmu-vmsa: Make use of IOMMU_OF_DECLARE() Magnus Damm <magnus.damm@gmail.com> - 2016-03-17 17:30 +0100
  [PATCH 03/10] iommu/ipmmu-vmsa: Teach xlate() to skip disabled iommus Magnus Damm <magnus.damm@gmail.com> - 2016-03-17 17:30 +0100
    Re: [PATCH 03/10] iommu/ipmmu-vmsa: Teach xlate() to skip disabled iommus Geert Uytterhoeven <geert@linux-m68k.org> - 2016-03-18 10:50 +0100
  [PATCH 08/10] iommu/ipmmu-vmsa: Make IMBUSCTR setup optional Magnus Damm <magnus.damm@gmail.com> - 2016-03-17 17:30 +0100
  [PATCH 04/10] iommu/ipmmu-vmsa: IPMMU device is 64-bit bus master Magnus Damm <magnus.damm@gmail.com> - 2016-03-17 17:30 +0100
  [PATCH 02/10] iommu/ipmmu-vmsa: Enable multi context support Magnus Damm <magnus.damm@gmail.com> - 2016-03-17 17:30 +0100

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