From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751341AbaIJNEn (ORCPT ); Wed, 10 Sep 2014 09:04:43 -0400 Received: from service87.mimecast.com ([91.220.42.44]:48563 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751245AbaIJNEk (ORCPT ); Wed, 10 Sep 2014 09:04:40 -0400 Date: Wed, 10 Sep 2014 14:04:32 +0100 From: Liviu Dudau To: Rob Herring Cc: Bjorn Helgaas , Arnd Bergmann , Rob Herring , Jason Gunthorpe , Benjamin Herrenschmidt , Catalin Marinas , Will Deacon , Russell King , linux-pci , Linus Walleij , Tanmay Inamdar , Grant Likely , Sinan Kaya , Jingoo Han , Kukjin Kim , Suravee Suthikulanit , linux-arch , LKML , Device Tree ML , LAKML , "grant.likely@linaro.org" Subject: Re: [PATCH v10 07/10] OF: Introduce helper function for getting PCI domain_nr Message-ID: <20140910130432.GB27864@e106497-lin.cambridge.arm.com> References: <1410184472-17630-1-git-send-email-Liviu.Dudau@arm.com> <1410184472-17630-8-git-send-email-Liviu.Dudau@arm.com> <20140908145459.GO27864@e106497-lin.cambridge.arm.com> <20140908155931.GP27864@e106497-lin.cambridge.arm.com> MIME-Version: 1.0 In-Reply-To: <20140908155931.GP27864@e106497-lin.cambridge.arm.com> User-Agent: Mutt/1.5.22 (2013-10-16) X-OriginalArrivalTime: 10 Sep 2014 13:04:33.0624 (UTC) FILETIME=[C41CBD80:01CFCCF7] X-MC-Unique: 114091014043511901 Content-Type: multipart/mixed; boundary="d6Gm4EdcadzBjdND" Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --d6Gm4EdcadzBjdND Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Sep 08, 2014 at 04:59:31PM +0100, Liviu Dudau wrote: > On Mon, Sep 08, 2014 at 04:27:36PM +0100, Rob Herring wrote: > > On Mon, Sep 8, 2014 at 9:54 AM, Liviu Dudau wrote= : > > > On Mon, Sep 08, 2014 at 03:27:56PM +0100, Rob Herring wrote: > > >> On Mon, Sep 8, 2014 at 8:54 AM, Liviu Dudau wr= ote: > > >> > Add of_pci_get_domain_nr() to retrieve the PCI domain number > > >> > of a given device from DT. If the information is not present, > > >> > the function can be requested to allocate a new domain number. > > >> > > > >> > Cc: Bjorn Helgaas > > >> > Cc: Arnd Bergmann > > >> > Cc: Grant Likely > > >> > Cc: Rob Herring > > >> > Reviewed-by: Catalin Marinas > > >> > Signed-off-by: Liviu Dudau > > >> > --- > > >> > drivers/of/of_pci.c | 34 ++++++++++++++++++++++++++++++++++ > > >> > include/linux/of_pci.h | 7 +++++++ > > >> > 2 files changed, 41 insertions(+) > > >> > > > >> > diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c > > >> > index 8481996..a107edb 100644 > > >> > --- a/drivers/of/of_pci.c > > >> > +++ b/drivers/of/of_pci.c > > >> > @@ -89,6 +89,40 @@ int of_pci_parse_bus_range(struct device_node *= node, struct resource *res) > > >> > } > > >> > EXPORT_SYMBOL_GPL(of_pci_parse_bus_range); > > >> > > > >> > +static atomic_t of_domain_nr =3D ATOMIC_INIT(-1); > > >> > + > > >> > +/** > > >> > + * This function will try to obtain the host bridge domain number= by > > >> > + * using of_alias_get_id() call with "pci-domain" as a stem. If t= hat > > >> > + * fails, a local allocator will be used. The local allocator can > > >> > + * be requested to return a new domain_nr if the information is m= issing > > >> > + * from the device tree. > > >> > + * > > >> > + * @node: device tree node with the domain information > > >> > + * @allocate_if_missing: if DT lacks information about the domain= nr, > > >> > + * allocate a new number. > > >> > + * > > >> > + * Returns the associated domain number from DT, or a new domain = number > > >> > + * if DT information is missing and @allocate_if_missing is true.= If > > >> > + * @allocate_if_missing is false then the last allocated domain n= umber > > >> > + * will be returned. > > >> > + */ > > >> > +int of_pci_get_domain_nr(struct device_node *node, bool allocate_= if_missing) > > >> > +{ > > >> > + int domain; > > >> > + > > >> > + domain =3D of_alias_get_id(node, "pci-domain"); > > >> > + if (domain =3D=3D -ENODEV) { > > >> > + if (allocate_if_missing) > > >> > + domain =3D atomic_inc_return(&of_domain_nr= ); > > >> > + else > > >> > + domain =3D atomic_read(&of_domain_nr); > > >> > > >> This function seems a bit broken to me. It is overloaded with too ma= ny > > >> different outcomes. Think about how this would work if you have > > >> multiple PCI buses and a mixture of having pci-domain aliases or not= . > > >> Aren't domain numbers global? Allocation should then start outside o= f > > >> the range of alias ids. > > >> > > >> Rob > > >> > > > > > > Rob, > > > > > > Would this version make more sense? > >=20 > > No. > >=20 Hi Rob, Here is an updated version of the patch. I have implemented a separate func= tion for getting the max domain number from the device tree and use the result a= s the start value + 1 for the allocator. Best regards, Liviu --=20 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- =C2=AF\_(=E3=83=84)_/=C2=AF --d6Gm4EdcadzBjdND Content-Type: text/x-diff; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="0001-OF-Introduce-helper-function-for-getting-PCI-domain_.patch" >>From 77257fceaa8fbd74d6132fcf57c3af14bd48c0ae Mon Sep 17 00:00:00 2001 From: Liviu Dudau Date: Mon, 4 Aug 2014 17:03:04 +0100 Subject: [PATCH v10 07/10] OF: Introduce helper function for getting PCI do= main_nr Add of_pci_get_domain_nr() to retrieve the PCI domain number of a given device from DT. If the information is not present, the function can be requested to allocate a new domain number. Cc: Bjorn Helgaas Cc: Arnd Bergmann Cc: Grant Likely Cc: Rob Herring Reviewed-by: Catalin Marinas Signed-off-by: Liviu Dudau --- drivers/of/of_pci.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++= ++++ include/linux/of_pci.h | 7 ++++++ 2 files changed, 69 insertions(+) diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c index 8481996..3560401 100644 --- a/drivers/of/of_pci.c +++ b/drivers/of/of_pci.c @@ -3,6 +3,8 @@ #include #include =20 +#include "of_private.h" + static inline int __of_pci_pci_compare(struct device_node *node, =09=09=09=09 unsigned int data) { @@ -89,6 +91,66 @@ int of_pci_parse_bus_range(struct device_node *node, str= uct resource *res) } EXPORT_SYMBOL_GPL(of_pci_parse_bus_range); =20 +static atomic_t of_domain_nr =3D ATOMIC_INIT(-1); + +/* + * Get the maximum value for a domain number from the device tree + */ +static int of_get_max_pci_domain_nr(void) +{ +=09struct alias_prop *app; +=09int max_domain =3D -1; + +=09mutex_lock(&of_mutex); +=09list_for_each_entry(app, &aliases_lookup, link) { +=09=09if (strncmp(app->stem, "pci-domain", 10) !=3D 0) +=09=09=09continue; + +=09=09max_domain =3D max(max_domain, app->id); +=09} +=09mutex_unlock(&of_mutex); + +=09return max_domain; +} + +/** + * This function will try to obtain the host bridge domain number by + * using of_alias_get_id() call with "pci-domain" as a stem. If that + * fails, a local allocator will be used. The local allocator can + * be requested to return a new domain_nr if the information is missing + * from the device tree. + * + * @node: device tree node with the domain information + * @allocate_if_missing: if DT lacks information about the domain nr, + * allocate a new number. + * + * Returns the associated domain number from DT, or a new domain number + * if DT information is missing and @allocate_if_missing is true. If + * @allocate_if_missing is false then the last allocated domain number + * will be returned. + */ +int of_pci_get_domain_nr(struct device_node *node, bool allocate_if_missin= g) +{ +=09int domain; + +=09domain =3D atomic_read(&of_domain_nr); +=09if (of_domain_nr =3D=3D -1) { +=09=09/* first run, get max defined domain nr in device tree */ +=09=09domain =3D of_get_max_pci_domain_nr(); +=09=09/* then set the start value for allocator to be max + 1 */ +=09=09atomic_set(&of_domain_nr, domain + 1); +=09} +=09domain =3D of_alias_get_id(node, "pci-domain"); +=09if (domain =3D=3D -ENODEV) { +=09=09domain =3D atomic_read(&of_domain_nr); +=09=09if (allocate_if_missing) +=09=09=09atomic_inc(&of_domain_nr); +=09} + +=09return domain; +} +EXPORT_SYMBOL_GPL(of_pci_get_domain_nr); + #ifdef CONFIG_PCI_MSI =20 static LIST_HEAD(of_pci_msi_chip_list); diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h index dde3a4a..3a3824c 100644 --- a/include/linux/of_pci.h +++ b/include/linux/of_pci.h @@ -15,6 +15,7 @@ struct device_node *of_pci_find_child_device(struct devic= e_node *parent, int of_pci_get_devfn(struct device_node *np); int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin); int of_pci_parse_bus_range(struct device_node *node, struct resource *res)= ; +int of_pci_get_domain_nr(struct device_node *node, bool allocate_if_missin= g); #else static inline int of_irq_parse_pci(const struct pci_dev *pdev, struct of_p= handle_args *out_irq) { @@ -43,6 +44,12 @@ of_pci_parse_bus_range(struct device_node *node, struct = resource *res) { =09return -EINVAL; } + +static inline int +of_pci_get_domain_nr(struct device_node *node, bool allocate_if_missing) +{ +=09return -1; +} #endif =20 #if defined(CONFIG_OF) && defined(CONFIG_PCI_MSI) --=20 2.0.4 --d6Gm4EdcadzBjdND--