Re: [PATCH 3/4] iommu/rockchip: Play nice in multi-platform builds

["Heiko Stübner" <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>]

Hi Thierry,

Am Mittwoch, 4. Februar 2015, 08:58:09 schrieb Thierry Reding:
> From: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> 
> The Rockchip IOMMU driver unconditionally executes code and registers a
> struct iommu_ops with the platform bus irrespective of whether it runs
> on a Rockchip SoC or not. This causes problems in multi-platform kernels
> where drivers for other SoCs will no longer be able to register their
> own struct iommu_ops or even try to use a struct iommu_ops for an IOMMU
> that obviously isn't there.
> 
> The smallest fix I could think of is to check for the existence of any
> Rockchip IOMMU devices in the device tree and skip initialization
> otherwise.
> 
> This fixes a problem on Tegra20 where the DRM driver will try to use the
> obviously non-existent Rockchip IOMMU.
> 
> Reported-by: Nicolas Chauvet <kwizart-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Cc: Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>
> Cc: Daniel Kurtz <djkurtz-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> Signed-off-by: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

Reviewed-by: Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>

on a rk3288-firefly with drm through the hdmi connector
Tested-by: Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>