From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752503AbaCFKg3 (ORCPT ); Thu, 6 Mar 2014 05:36:29 -0500 Received: from service87.mimecast.com ([91.220.42.44]:51334 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751545AbaCFKg0 convert rfc822-to-8bit (ORCPT ); Thu, 6 Mar 2014 05:36:26 -0500 Date: Thu, 6 Mar 2014 10:36:20 +0000 From: Liviu Dudau To: Russell King - ARM Linux Cc: linux-pci , Bjorn Helgaas , Catalin Marinas , Will Deacon , linaro-kernel , "devicetree@vger.kernel.org" , Arnd Bergmann , Benjamin Herrenschmidt , LKML , Tanmay Inamdar , LAKML Subject: Re: [PATCH v6 1/3] Fix ioport_map() for !CONFIG_GENERIC_IOMAP cases. Message-ID: <20140306103620.GB6457@e106497-lin.cambridge.arm.com> Mail-Followup-To: Russell King - ARM Linux , linux-pci , Bjorn Helgaas , Catalin Marinas , Will Deacon , linaro-kernel , "devicetree@vger.kernel.org" , Arnd Bergmann , Benjamin Herrenschmidt , LKML , Tanmay Inamdar , LAKML References: <1394020150-1875-1-git-send-email-Liviu.Dudau@arm.com> <1394020150-1875-2-git-send-email-Liviu.Dudau@arm.com> <20140305233135.GZ21483@n2100.arm.linux.org.uk> MIME-Version: 1.0 In-Reply-To: <20140305233135.GZ21483@n2100.arm.linux.org.uk> User-Agent: Mutt/1.5.22 (2013-10-16) X-OriginalArrivalTime: 06 Mar 2014 10:36:21.0774 (UTC) FILETIME=[EA7F1AE0:01CF3927] X-MC-Unique: 114030610362313401 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 05, 2014 at 11:31:35PM +0000, Russell King - ARM Linux wrote: > On Wed, Mar 05, 2014 at 11:49:08AM +0000, Liviu Dudau wrote: > > The inline version of ioport_map() that gets used when !CONFIG_GENERIC_IOMAP > > is wrong. It returns a mapped (i.e. virtual) address that can start from > > zero and completely ignores the PCI_IOBASE and IO_SPACE_LIMIT that most > > architectures that use !CONFIG_GENERIC_MAP define. > > What value does PCI_IOBASE and IO_SPACE_LIMIT have on other architectures > who make use of asm-generic/io.h ? Hi Russell, Sorry for being a bit opaque in the commit message, I probably conflated two issues into one. The first issue is that ioport_map() is supposed to return a virtual address for the IO port. I struggle to believe that a virtual address of zero for IO is valid for most architectures other than x86. My guess is that most of the architectures that you have listed as including asm-generic/io.h have no support for PCI whatsoever. The other issue is that *if* you specify an PCI_IOBASE and don't come up with your own version of ioport_map() then you get the wrong virtual addresses back. One way to fix all this is to use PCI_IOBASE inside the generic version and to define it to a non-zero values for architectures that have memory mapped IO. That should reduce the number of custom versions of ioport_map() that we currently have. The other implied message that I'm getting is that you are suggesting that the commit message is generalising a bit too much? With that I agree, in light of your analysis. I can change it to something like: The inline version of ioport_map() that gets used for !CONFIG_GENERIC_IOMAP is wrong when PCI_IOBASE has a non-zero value. The function is supposed to return a virtual address for IO ports and for architectures that memory map the IO areas that is giving incorrect results as it ignores PCI_IOBASE. Fix this and also limit the port range to the IO_SPACE_LIMIT mask. > > $ git grep asm-generic/io.h arch/ > arch/arc/include/asm/io.h:#include > arch/blackfin/include/asm/io.h:#include > arch/metag/include/asm/io.h:#include > arch/microblaze/include/asm/io.h:/* from asm-generic/io.h */ > arch/openrisc/include/asm/io.h:#include > arch/s390/include/asm/io.h:#include > arch/score/include/asm/io.h:#include > arch/unicore32/include/asm/io.h:#include PCI_IOBASE = PKUNITY_PCILIO_BASE = PKUNITY_PCI_BASE + 0x00030000 = io_p2v(0x80000000) + 0x00030000 All other ones bar arm64 are either happy with PCI_IOBASE being zero (proxy for "no PCI support") or define their own version of ioport_map(). Best regards, Liviu > arch/xtensa/include/asm/io.h:#include > $ arch/arc/include/asm/io.h:#define PCI_IOBASE ((void __iomem *)0) > arch/arm64/include/asm/io.h:#define PCI_IOBASE ((void __iomem *)(MODULES_VADDR - SZ_2M)) > arch/arm64/include/asm/io.h: return readb(addr + PCI_IOBASE); > arch/arm64/include/asm/io.h: return readw(addr + PCI_IOBASE); > arch/arm64/include/asm/io.h: return readl(addr + PCI_IOBASE); > arch/arm64/include/asm/io.h: writeb(b, addr + PCI_IOBASE); > arch/arm64/include/asm/io.h: writew(b, addr + PCI_IOBASE); > arch/arm64/include/asm/io.h: writel(b, addr + PCI_IOBASE); > arch/arm64/include/asm/io.h: *buf++ = __raw_readb(addr + PCI_IOBASE); > arch/arm64/include/asm/io.h: *buf++ = __raw_readw(addr + PCI_IOBASE); > arch/arm64/include/asm/io.h: *buf++ = __raw_readl(addr + PCI_IOBASE); > arch/arm64/include/asm/io.h: __raw_writeb(*buf++, addr + PCI_IOBASE); > arch/arm64/include/asm/io.h: __raw_writew(*buf++, addr + PCI_IOBASE); > arch/arm64/include/asm/io.h: __raw_writel(*buf++, addr + PCI_IOBASE); > arch/unicore32/include/asm/io.h:#define PCI_IOBASE PKUNITY_PCILIO_BASE > arch/unicore32/include/asm/io.h:#define PIO_OFFSET (unsigned int)(PCI_IOBASE) > > > -- > FTTC broadband for 0.8mile line: now at 9.7Mbps down 460kbps up... slowly > improving, and getting towards what was expected from it. > -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯