From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752263AbcELKo0 (ORCPT ); Thu, 12 May 2016 06:44:26 -0400 Received: from mail-yw0-f173.google.com ([209.85.161.173]:34885 "EHLO mail-yw0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751491AbcELKoX (ORCPT ); Thu, 12 May 2016 06:44:23 -0400 MIME-Version: 1.0 In-Reply-To: <20160511224314.GD28812@localhost> References: <1462893601-8937-1-git-send-email-tn@semihalf.com> <1462893601-8937-8-git-send-email-tn@semihalf.com> <20160511101101.GA16101@red-moon> <20160511224314.GD28812@localhost> From: Jayachandran C Date: Thu, 12 May 2016 16:13:43 +0530 Message-ID: Subject: Re: [PATCH V7 07/11] pci, acpi: Handle ACPI companion assignment. To: Bjorn Helgaas Cc: "Rafael J. Wysocki" , Lorenzo Pieralisi , Tomasz Nowicki , Arnd Bergmann , Will Deacon , Catalin Marinas , Hanjun Guo , Sinan Kaya , robert.richter@caviumnetworks.com, Marcin Wojtas , Liviu.Dudau@arm.com, David Daney , Wangyijing , Suravee Suthikulanit , Mark Salter , Linux PCI , "linux-arm-kernel@lists.infradead.org" , ACPI Devel Maling List , Linux Kernel Mailing List , "linaro-acpi@lists.linaro.org" , Jon Masters , Andrea Gallo , Duc Dang , jeremy.linton@arm.com, liudongdong3@huawei.com, Christopher Covington Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 12, 2016 at 4:13 AM, Bjorn Helgaas wrote: > On Wed, May 11, 2016 at 10:30:51PM +0200, Rafael J. Wysocki wrote: >> On Wed, May 11, 2016 at 12:11 PM, Lorenzo Pieralisi >> wrote: >> > On Tue, May 10, 2016 at 08:37:00PM +0200, Rafael J. Wysocki wrote: >> >> On Tue, May 10, 2016 at 5:19 PM, Tomasz Nowicki wrote: >> >> > This patch provides a way to set the ACPI companion in PCI code. >> >> > We define acpi_pci_set_companion() to set the ACPI companion pointer and >> >> > call it from PCI core code. The function is stub for now. >> >> > >> >> > Signed-off-by: Jayachandran C >> >> > Signed-off-by: Tomasz Nowicki >> >> > --- >> >> > drivers/pci/probe.c | 2 ++ >> >> > include/linux/pci-acpi.h | 4 ++++ >> >> > 2 files changed, 6 insertions(+) >> >> > >> >> > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c >> >> > index 8004f67..fb0b752 100644 >> >> > --- a/drivers/pci/probe.c >> >> > +++ b/drivers/pci/probe.c >> >> > @@ -12,6 +12,7 @@ >> >> > #include >> >> > #include >> >> > #include >> >> > +#include >> >> > #include >> >> > #include >> >> > #include >> >> > @@ -2141,6 +2142,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus, >> >> > bridge->dev.parent = parent; >> >> > bridge->dev.release = pci_release_host_bridge_dev; >> >> > dev_set_name(&bridge->dev, "pci%04x:%02x", pci_domain_nr(b), bus); >> >> > + acpi_pci_set_companion(bridge); >> >> >> >> Yes, we'll probably add something similar here. >> >> >> >> Do I think now is the right time to do that? No. >> >> >> >> > error = pcibios_root_bridge_prepare(bridge); >> >> > if (error) { >> >> > kfree(bridge); >> >> > diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h >> >> > index 09f9f02..1baa515 100644 >> >> > --- a/include/linux/pci-acpi.h >> >> > +++ b/include/linux/pci-acpi.h >> >> > @@ -111,6 +111,10 @@ static inline void acpi_pci_add_bus(struct pci_bus *bus) { } >> >> > static inline void acpi_pci_remove_bus(struct pci_bus *bus) { } >> >> > #endif /* CONFIG_ACPI */ >> >> > >> >> > +static inline void acpi_pci_set_companion(struct pci_host_bridge *bridge) >> >> > +{ >> >> > +} >> >> > + >> >> > static inline int acpi_pci_bus_domain_nr(struct pci_bus *bus) >> >> > { >> >> > return 0; >> >> > -- >> >> >> >> Honestly, to me it looks like this series is trying very hard to avoid >> >> doing any PCI host bridge configuration stuff from arch/arm64/ >> >> although (a) that might be simpler and (b) it would allow us to >> >> identify the code that's common between *all* architectures using ACPI >> >> support for host bridge configuration and to move *that* to a common >> >> place later. As done here it seems to be following the "ARM64 is >> >> generic and the rest of the world is special" line which isn't really >> >> helpful. >> > >> > I think patch [1-2] should be merged regardless (they may require minor >> > tweaks if we decide to move pci_acpi_scan_root() to arch/arm64 though, >> > for include files location). I guess you are referring to patch 8 in >> > your comments above, which boils down to deciding whether: >> > >> > - pci_acpi_scan_root() (and unfortunately all the MCFG/ECAM handling that >> > goes with it) should live in arch/arm64 or drivers/acpi >> >> To be precise, everything under #ifdef CONFIG_ACPI_PCI_HOST_GENERIC or >> equivalent is de facto ARM64-specific, because (as it stands in the >> patch series) ARM64 is the only architecture that will select that >> option. Unless you are aware of any more architectures planning to >> use ACPI (and I'm not aware of any), it will stay the only >> architecture selecting it in the foreseeable future. >> >> Therefore you could replace CONFIG_ACPI_PCI_HOST_GENERIC with >> CONFIG_ARM64 everywhere in that code which is why in my opinion the >> code should live somewhere under arch/arm64/. >> >> Going forward, it should be possible to identify common parts of the >> PCI host bridge configuration code in arch/ and move it to >> drivers/acpi/ or drivers/pci/, but I bet that won't be the entire code >> this series puts under CONFIG_ACPI_PCI_HOST_GENERIC. >> >> The above leads to a quite straightforward conclusion about the order >> in which to do things: I'd add ACPI support for PCI host bridge on >> ARM64 following what's been done on ia64 (as x86 is more quirky and >> kludgy overall) as far as reasonably possible first and then think >> about moving common stuff to a common place. > > That does seem like a reasonable approach. I had hoped to get more of > this in for v4.7, but we don't have much time left. Maybe some of > Rafael's comments can be addressed by moving and slight restructuring > and we can still squeeze it in. > > The first three patches: > > PCI: Provide common functions for ECAM mapping > PCI: generic, thunder: Use generic ECAM API > PCI, of: Move PCI I/O space management to PCI core code > > seem relatively straightforward, and I applied them to pci/arm64 with > the intent of merging them unless there are objections. I made the > following tweaks, mainly to try to improve some error messages: > > diff --git a/drivers/pci/ecam.c b/drivers/pci/ecam.c > index 3d52005..e1add01 100644 > --- a/drivers/pci/ecam.c > +++ b/drivers/pci/ecam.c > @@ -24,9 +24,9 @@ > #include "ecam.h" > > /* > - * On 64 bit systems, we do a single ioremap for the whole config space > - * since we have enough virtual address range available. On 32 bit, do an > - * ioremap per bus. > + * On 64-bit systems, we do a single ioremap for the whole config space > + * since we have enough virtual address range available. On 32-bit, we > + * ioremap the config space for each bus individually. > */ > static const bool per_bus_mapping = !config_enabled(CONFIG_64BIT); > > @@ -42,6 +42,7 @@ struct pci_config_window *pci_ecam_create(struct device *dev, > { > struct pci_config_window *cfg; > unsigned int bus_range, bus_range_max, bsz; > + struct resource *conflict; > int i, err; > > if (busr->start > busr->end) > @@ -58,10 +59,10 @@ struct pci_config_window *pci_ecam_create(struct device *dev, > bus_range = resource_size(&cfg->busr); > bus_range_max = resource_size(cfgres) >> ops->bus_shift; > if (bus_range > bus_range_max) { > - dev_warn(dev, "bus max %#x reduced to %#x", > - bus_range, bus_range_max); > bus_range = bus_range_max; > cfg->busr.end = busr->start + bus_range - 1; > + dev_warn(dev, "ECAM area %pR can only accommodate %pR (reduced from %pR desired)\n", > + cfgres, &cfg->busr, busr); > } > bsz = 1 << ops->bus_shift; > > @@ -70,9 +71,11 @@ struct pci_config_window *pci_ecam_create(struct device *dev, > cfg->res.flags = IORESOURCE_MEM | IORESOURCE_BUSY; > cfg->res.name = "PCI ECAM"; > > - err = request_resource(&iomem_resource, &cfg->res); > - if (err) { > - dev_err(dev, "request ECAM res %pR failed\n", &cfg->res); > + conflict = request_resource(&iomem_resource, &cfg->res); > + if (conflict) { > + err = -EBUSY; > + dev_err(dev, "can't claim ECAM area %pR: address conflict with %s %pR\n", > + &cfg->res, conflict->name, conflict); > goto err_exit; > } > > diff --git a/drivers/pci/ecam.h b/drivers/pci/ecam.h > index 1ad2176..9878beb 100644 > --- a/drivers/pci/ecam.h > +++ b/drivers/pci/ecam.h > @@ -33,7 +33,7 @@ struct pci_ecam_ops { > > /* > * struct to hold the mappings of a config space window. This > - * is expected to be used as sysdata for PCI controlllers which > + * is expected to be used as sysdata for PCI controllers that > * use ECAM. > */ > struct pci_config_window { > @@ -43,11 +43,11 @@ struct pci_config_window { > struct pci_ecam_ops *ops; > union { > void __iomem *win; /* 64-bit single mapping */ > - void __iomem **winp; /* 32-bit per bus mapping */ > + void __iomem **winp; /* 32-bit per-bus mapping */ > }; > }; > > -/* create and free for pci_config_window */ > +/* create and free pci_config_window */ > struct pci_config_window *pci_ecam_create(struct device *dev, > struct resource *cfgres, struct resource *busr, > struct pci_ecam_ops *ops); > @@ -56,11 +56,11 @@ void pci_ecam_free(struct pci_config_window *cfg); > /* map_bus when ->sysdata is an instance of pci_config_window */ > void __iomem *pci_ecam_map_bus(struct pci_bus *bus, unsigned int devfn, > int where); > -/* default ECAM ops, bus shift 20, generic read and write */ > +/* default ECAM ops */ > extern struct pci_ecam_ops pci_generic_ecam_ops; > > #ifdef CONFIG_PCI_HOST_GENERIC > -/* for DT based pci controllers that support ECAM */ > +/* for DT-based PCI controllers that support ECAM */ > int pci_host_common_probe(struct platform_device *pdev, > struct pci_ecam_ops *ops); > #endif If we are moving the ACPI/PCI code from drivers/acpi to arch/arm64/ , there is an issue in having the header file ecam.h in drivers/pci The current include of "../pci/ecam.h" is slightly ugly (Arnd and David had already noted this), but including the driver header from arch code would be even worse. I can either merge ecam.h into include/linux/pci.h or move it to a new file include/linux/pci-ecam.h, any suggestion on which is preferable? JC.