> -----Original Message----- > From: devicetree-discuss- > bounces+stuart.yoder=freescale....@lists.ozlabs.org [mailto:devicetree- > discuss-bounces+stuart.yoder=freescale....@lists.ozlabs.org] On Behalf Of > Benjamin Herrenschmidt > Sent: Monday, February 07, 2011 3:46 PM > To: Meador Inge > Cc: Hollis Blanchard; devicetree-disc...@lists.ozlabs.org; linuxppc- > d...@lists.ozlabs.org > Subject: Re: [PATCH v3 1/4] powerpc: Removing support for 'protected- > sources' > > > > In my previous reply I said that "it is not so much as a need as it is > > a potential simplification." After further reflection, I don't think > > that is completely true. As we get into AMP systems with higher core > > counts, then implementing this functionality using the existing > > "protected-sources" implementation versus the new "pic-no-reset" work > > is going to be harder to maintain. > > I'm not arguing that your approach isn't more suitable for AMP systems, I > just want to leave the existing protected-sources mechanism alone. I'm not > opposing adding a new, better, mechanism for newer platforms. > > However, I'd name it differently. "pic-no-reset" doesn't carry enough > meaning in that case. What we want to point out here is that the PIC has > been pre-initialized. > > Another option, which may be cleaner, is to stick to "no-reset" (no need > for pic- prefix) and make it do just that (prevent the reset), and then use > a positive variant of "protected-sources", call it "allowed-sources". Maybe > even make it a series of ranges. Then have the MPIC only access these. > > I think this is more robust as it would also prevent "accidental" use of > the wrong sources (bad device-tree, drivers that let you muck around with > irq numbers, etc...).
What is the use case for "allowed-sources"? For AMP the only device nodes in your device tree should be your AMP partition's devices, thus any interrupt specifiers in your dev tree are "allowed". The MPIC is a shared device and thus the need for no-reset. So, all newer platforms should need is "no-reset". Stuart _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
