On Wed, Sep 30, 2020 at 06:36:52PM +0300, Dmitry Osipenko wrote: > I'... > >> + struct tegra_mc *mc = devm_tegra_get_memory_controller(dev); > >> + struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > > > > It looks to me like the only reason why you need this new global API is > > because PCI devices may not have a device tree node with a phandle to > > the IOMMU. However, SMMU support for PCI will only be enabled if the > > root complex has an iommus property, right? In that case, can't we > > simply do something like this: > > > > if (dev_is_pci(dev)) > > np = find_host_bridge(dev)->of_node; > > else > > np = dev->of_node; > > > > ? I'm not sure exactly what find_host_bridge() is called, but I'm pretty > > sure that exists. > > > > Once we have that we can still iterate over the iommus property and do > > not need to rely on this global variable. > > This sounds more complicated than the current variant. I don't think so. It's actually very clear and explicit. And yes, this might be a little more work (and honestly, this is what? a handful of lines?) than accessing a global variable, but that's a fair price to pay for proper encapsulation. > Secondly, I'm already about to use the new tegra_get_memory_controller() > API for all the T20/30/124/210 EMC and devfreq drivers. Also, this really proves the point I was trying to make about how this is going to proliferate... Thierry
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