From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Subject: Re: [RFC PATCH RESEND v2] of/pci: Provide support for parsing PCI DT ranges property Date: Thu, 21 Mar 2013 17:06:25 +0100 Message-ID: <20130321170625.2a1bf226@skate> References: <1362140616-19346-1-git-send-email-Andrew.Murray@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1362140616-19346-1-git-send-email-Andrew.Murray@arm.com> Sender: linux-kernel-owner@vger.kernel.org To: Andrew Murray Cc: "linux-kernel@vger.kernel.org" , "devicetree-discuss@lists.ozlabs.org" , "rob.herring@calxeda.com" , Grant Likely , Thierry Reding , "linux-pci@vger.kernel.org" , Linus Walleij , Liviu Dudau List-Id: devicetree@vger.kernel.org Dear Andrew Murray, On Fri, 1 Mar 2013 12:23:36 +0000, Andrew Murray wrote: > This patch factors out common implementations patterns to reduce overall kernel > code and provide a means for host bridge drivers to directly obtain struct > resources from the DT's ranges property without relying on architecture specific > DT handling. This will make it easier to write archiecture independent host bridge > drivers and mitigate against further duplication of DT parsing code. > > This patch can be used in the following way: > > struct of_pci_range_iter iter; > for_each_of_pci_range(&iter, np) { > > //directly access properties of the address range, e.g.: > //iter.pci_space, iter.pci_addr, iter.cpu_addr, iter.size or > //iter.flags > > //alternatively obtain a struct resource, e.g.: > //struct resource res; > //range_iter_fill_resource(iter, np, res); > } > > Additionally the implementation takes care of adjacent ranges and merges them > into a single range (as was the case with powerpc and microblaze). > > The modifications to microblaze, mips and powerpc have not been tested. > > v2: > This follows on from suggestions made by Grant Likely > (marc.info/?l=linux-kernel&m=136079602806328) > > Signed-off-by: Andrew Murray > Signed-off-by: Liviu Dudau Thanks, I've tested this successfully with the Marvell PCIe driver. I'm about to send a new version of the Marvell PCIe patch set that includes this RFC proposal. I only made two small changes compared to your version, detailed below. > +#define for_each_of_pci_range(iter, np) \ > + for (; of_pci_process_ranges(iter, np);) In the initial part of the loop, I added a memset() to initialize to zero the "iter" structure. Otherwise, if you forget to do it before calling of_pci_process_ranges(), it may crash (depending on the random values present in the uninitialized structure). > +#define range_iter_fill_resource(iter, np, res) \ > + do { \ > + res->flags = iter.flags; \ > + res->start = iter.cpu_addr; \ > + res->end = iter.cpu_addr + iter.size - 1; \ > + res->parent = res->child = res->sibling = NULL; \ > + res->name = np->full_name; \ > + } while (0) And here, I enclosed all the usage of the macro parameters in parenthesis. Like (res)->flags instead of res->flags. If you don't do that, then passing &foobar as the 'res' parameter causes some compilation failure because &foobar->res is not valid, while (&foobar)->res is. Best regards, Thomas -- Thomas Petazzoni, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com