From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Pieralisi Subject: Re: [PATCH V2 3/5] PCI: xilinx: Modifying AXI PCIe Host Bridge driver to work on both Zynq and Microblaze Date: Thu, 28 Jan 2016 14:49:45 +0000 Message-ID: <20160128144944.GA12690@red-moon> References: <1452620173-4905-1-git-send-email-bharatku@xilinx.com> <1917083.LB4Ng3Y2yP@wuerfel> <8520D5D51A55D047800579B094147198258741F5@XAP-PVEXMBX01.xlnx.xilinx.com> <3706176.5tvYx0gSBz@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <3706176.5tvYx0gSBz@wuerfel> Sender: linux-kernel-owner@vger.kernel.org To: Arnd Bergmann Cc: Bharat Kumar Gogada , "bhelgaas@google.com" , Michal Simek , "paul.burton@imgtec.com" , "yinghai@kernel.org" , "wangyijing@huawei.com" , "robh@kernel.org" , "russell.joyce@york.ac.uk" , Soren Brinkmann , "jiang.liu@linux.intel.com" , "pawel.moll@arm.com" , "mark.rutland@arm.com" , "ijc+devicetree@hellion.org.uk" , "galak@codeaurora.org" , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , linux-pci@ List-Id: devicetree@vger.kernel.org On Thu, Jan 28, 2016 at 03:23:37PM +0100, Arnd Bergmann wrote: > On Thursday 28 January 2016 14:18:15 Bharat Kumar Gogada wrote: > > > > > > I see. In the upstream code you seem to do it in > > > pcibios_setup_bus_devices(), while arm64 and powerpc do it in > > > pcibios_add_device(). > > > > > No that function is not getting called with generic API's, its getting called with pcibios_init flow which is tightly bound with struct pci_controller microblaze specific structure. So I added pcibios_add_device in pci-common.c. > > Ok > > > > > May be we can add similar on arm and test out, but we might need some > > > > cleanup in arch/arm/kernel/bios32.c > > > > > > I think that would still just be a half-baked solution. This should really be fully > > > automatic. We could do it in the __weak > > > pcibios_add_device() for all architectures that don't override it when the bus > > > was probed from DT, or we could do it in pci_read_irq(). > > When will pci_read_irq() call get invoked ? > > This is called early on when a device gets created in pci_setup_device(), > so platforms can still override the value later. > > The idea here is that normally a BIOS stores the interrupt number in > the PCI_INTERRUPT_LINE config space byte, and we just read it from > there. Generally speaking though, for non-PC systems we tend to not > have a BIOS that writes these values to start with, and any values > stored in here have no meaning in combination with SPARSE_IRQ > and/or IRQ_DOMAINS because the bootloader or BIOS doesn't know > what IRQ number will refer to hardware IRQ line in Linux. I think the best way to handle this is through Matthew's series (below), in the interim a callback in arch code would do, we will clean it up when Matthew's series goes upstream, it should not take too long. http://www.spinics.net/lists/linux-pci/msg45950.html Thanks, Lorenzo