From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 14 Jan 2016 17:59:24 +0000 From: Lorenzo Pieralisi To: Mark Salter Cc: Sinan Kaya , Tomasz Nowicki , bhelgaas@google.com, arnd@arndb.de, will.deacon@arm.com, catalin.marinas@arm.com, rjw@rjwysocki.net, hanjun.guo@linaro.org, jiang.liu@linux.intel.com, Stefano.Stabellini@eu.citrix.com, robert.richter@caviumnetworks.com, mw@semihalf.com, Liviu.Dudau@arm.com, ddaney@caviumnetworks.com, tglx@linutronix.de, wangyijing@huawei.com, Suravee.Suthikulpanit@amd.com, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linaro-acpi@lists.linaro.org, jchandra@broadcom.com, jcm@redhat.com Subject: Re: [PATCH V3 00/21] MMCONFIG refactoring and support for ARM64 PCI hostbridge init based on ACPI Message-ID: <20160114175924.GC20706@red-moon> References: <1452691267-32240-1-git-send-email-tn@semihalf.com> <1452785393.28109.16.camel@redhat.com> <5697C0EB.4020404@codeaurora.org> <20160114161238.GA20706@red-moon> <1452789524.28109.24.camel@redhat.com> <20160114170723.GB20706@red-moon> <1452792723.28109.31.camel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 In-Reply-To: <1452792723.28109.31.camel@redhat.com> Sender: linux-acpi-owner@vger.kernel.org List-ID: On Thu, Jan 14, 2016 at 12:32:03PM -0500, Mark Salter wrote: > On Thu, 2016-01-14 at 17:07 +0000, Lorenzo Pieralisi wrote: > > On Thu, Jan 14, 2016 at 11:38:44AM -0500, Mark Salter wrote: > > > > [...] > > > > > You would lose that bet. AddressMinimum/Maximum describe the > > > PCI bus addresses. > > > > In the mainline DT (APM Mustang), the CPU physical address corresponding > > to IO space is 0xe010000000, PCI bus address is 0x0. > > > > >                 QWordIO (ResourceProducer, MinFixed, MaxFixed, PosDecode, EntireRange, > > >                     0x0000000000000000, // Granularity > > >                     0x0000000010000000, // Range Minimum > > > > > > >                     0x000000001000FFFF, // Range Maximum > > >                     0x000000E000000000, // Translation Offset > > > > See above, I will get the APM specifications to countercheck. > > The spec won't help other than to verify that the PCIe bridge supports > a 32-bit IO address space. The firmware sets the PCI bus base @ > 0x10000000 with a CPU base address for that window @ 0xe010000000. The > pci-xgene.c driver sets the PCI bus IO base address to whatever DT > tells it too. For ACPI, we have to use whatever the firmware set it to > and described it in the ACPI table. It makes sense, thank you for clarifying (and sorry for jumping to conclusions, I am a bit worried about the ACPI IO space descriptors specification and usage on arm64). > When I looked at this a while back, neither ACPI nor PCI had anything > which disallowed 32-bit IO space on the PCI bus. The 16-bit limit is > an x86 limit in the instruction set. We should ask Jiang to remove that check or to make it x86 only (does current mainline - where the offset is added to the resource start/end - work on ia64 ?) Thanks, Lorenzo > > > > > I agree with you we have to verify if this IO space limitation is > > real or it is just an x86ism, in which case we remove that check. > > > > Lorenzo > > >                     0x0000000000010000, // Length > > >                     ,, , TypeStatic) > > > > > > > > > > > > Jiang's patch: > > > > > > > > https://lkml.org/lkml/2015/12/16/249 > > > > > > > > parses the IO descriptors and stores the AddressMinimum, AddressMaximum > > > > in the IO resource (with AddressTranslation as offset which must be the > > > > *CPU* physical address mapping IO), from the log above it seems to me in > > > > AddressMinimum APM specifies the *CPU* physical address generating IO > > > > cycles. > > > > > > > > All in all, I was right to fear this would happen, and I already > > > > raised the point within the ACPI spec working group, ACPI IO > > > > descriptors specification is ambiguous and we must agree on how > > > > they have to be specified once for all. > > > > > > > > Lorenzo > > > >