From patchwork Thu Jul 9 01:54:16 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Luis R. Rodriguez" X-Patchwork-Id: 6752401 Return-Path: X-Original-To: patchwork-linux-fbdev@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id F066B9F319 for ; Thu, 9 Jul 2015 01:57:18 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2D51D20576 for ; Thu, 9 Jul 2015 01:57:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F187205EC for ; Thu, 9 Jul 2015 01:57:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753091AbbGIBzu (ORCPT ); Wed, 8 Jul 2015 21:55:50 -0400 Received: from mail-pa0-f51.google.com ([209.85.220.51]:34430 "EHLO mail-pa0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753137AbbGIByx (ORCPT ); Wed, 8 Jul 2015 21:54:53 -0400 Received: by pabvl15 with SMTP id vl15so141093851pab.1; Wed, 08 Jul 2015 18:54:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-type:content-transfer-encoding; bh=GCsywNeTxFihb5NCjnjiFUIa1TR5sDxVgczAZBw/GJk=; b=B2qiLQoHGatbDs3i20Pn0pif90g/v8iQ38NncM86tjukzxecKyVBeOMJPSzaJ7yi+H WHTLbx1pyPtBE5d3p+3uAt7/kB0NM+BjPFSypbIB1L+mUNNFfSzSvetu+/AELApDjtt4 ndSFiBl5ZX0A2ra/ObIrVEtaMeShn+Kf3Y2A3nSAvfJku8tLZm4fJ8tZyulIep4FsMaI oL3LFH6QBpDvdAAciglg48H94Kd0SX73IW+dsD56Oy6H9TIg0wj/JtXD1eka+v3xH3Ro lxrFm3mxVlQ9ig4d12vQZvTQuFBBTZr3IXx5jbkTxrEojFTy+O6e/F/JZNpkW0Rr9X3h FKQg== X-Received: by 10.68.137.104 with SMTP id qh8mr8299871pbb.114.1436406892305; Wed, 08 Jul 2015 18:54:52 -0700 (PDT) Received: from mcgrof@gmail.com ([2601:646:200:bc5b:ca60:ff:feda:57a7]) by smtp.gmail.com with ESMTPSA id pe3sm3895316pdb.55.2015.07.08.18.54.48 (version=TLSv1 cipher=RC4-SHA bits=128/128); Wed, 08 Jul 2015 18:54:50 -0700 (PDT) Received: by mcgrof@gmail.com (sSMTP sendmail emulation); Wed, 08 Jul 2015 18:54:47 -0700 From: "Luis R. Rodriguez" To: mingo@kernel.org Cc: bp@suse.de, arnd@arndb.de, bhelgaas@google.com, luto@amacapital.net, akpm@linux-foundation.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, tomi.valkeinen@ti.com, mst@redhat.com, toshi.kani@hp.com, linux-fbdev@vger.kernel.org, xen-devel@lists.xensource.com, benh@kernel.crashing.org, "Luis R. Rodriguez" , Antonino Daplas , Daniel Vetter , Dave Airlie , Dave Hansen , Davidlohr Bueso , david.vrabel@citrix.com, "H. Peter Anvin" , jbeulich@suse.com, Jean-Christophe Plagniol-Villard , Juergen Gross , konrad.wilk@oracle.com, linux-arch@vger.kernel.org, Mel Gorman , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= , Rusty Russell , Stefan Bader , Suresh Siddha , Thomas Gleixner , venkatesh.pallipadi@intel.com, =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= , Vlastimil Babka Subject: [PATCH v9 5/8] PCI: Add pci_iomap_wc() variants Date: Wed, 8 Jul 2015 18:54:16 -0700 Message-Id: <1436406859-1280-6-git-send-email-mcgrof@do-not-panic.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1436406859-1280-1-git-send-email-mcgrof@do-not-panic.com> References: <1436406859-1280-1-git-send-email-mcgrof@do-not-panic.com> MIME-Version: 1.0 Sender: linux-fbdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00,DKIM_SIGNED, RP_MATCHES_RCVD, T_DKIM_INVALID, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: "Luis R. Rodriguez" PCI BARs tell us whether prefetching is safe, but they don't say anything about write combining (WC). WC changes ordering rules and allows writes to be collapsed, so it's not safe in general to use it on a prefetchable region. Add pci_iomap_wc() and pci_iomap_wc_range() so drivers can take advantage of write combining when they know it's safe. On architectures that don't fully support WC, e.g., x86 without PAT, drivers for legacy framebuffers may get some of the benefit by using arch_phys_wc_add() in addition to pci_iomap_wc(). But arch_phys_wc_add() is unreliable and should be avoided in general. On x86, it uses MTRRs, which are limited in number and size, so the results will vary based on driver loading order. The goals of adding pci_iomap_wc() are to: - Give drivers an architecture-independent way to use WC so they can stop using interfaces like mtrr_add() (on x86, pci_iomap_wc() uses PAT when available). - Move toward using _PAGE_CACHE_MODE_UC, not _PAGE_CACHE_MODE_UC_MINUS, on x86 on ioremap_nocache() (see de33c442ed2a ("x86 PAT: fix performance drop for glx, use UC minus for ioremap(), ioremap_nocache() and pci_mmap_page_range()"). Signed-off-by: Luis R. Rodriguez Acked-by: Arnd Bergmann Cc: Andrew Morton Cc: Andy Lutomirski Cc: Antonino Daplas Cc: Arnd Bergmann Cc: benh@kernel.crashing.org Cc: bhelgaas@google.com Cc: Bjorn Helgaas Cc: Daniel Vetter Cc: Dave Airlie Cc: Dave Hansen Cc: Davidlohr Bueso Cc: david.vrabel@citrix.com Cc: H. Peter Anvin Cc: Ingo Molnar Cc: jbeulich@suse.com Cc: Jean-Christophe Plagniol-Villard Cc: Juergen Gross Cc: konrad.wilk@oracle.com Cc: linux-arch@vger.kernel.org Cc: linux-fbdev@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: Mel Gorman Cc: "Michael S. Tsirkin" Cc: Roger Pau Monné Cc: Rusty Russell Cc: Stefan Bader Cc: Suresh Siddha Cc: Thomas Gleixner Cc: Tomi Valkeinen Cc: Toshi Kani Cc: venkatesh.pallipadi@intel.com Cc: Ville Syrjälä Cc: Vlastimil Babka Link: http://lkml.kernel.org/r/1426893517-2511-6-git-send-email-mcgrof@do-not-panic.com Link: http://lkml.kernel.org/r/1435195342-26879-6-git-send-email-mcgrof@do-not-panic.com [ Move IORESOURCE_IO check up, space out statements for better readability. ] Signed-off-by: Borislav Petkov --- include/asm-generic/pci_iomap.h | 14 +++++++++ lib/pci_iomap.c | 66 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 80 insertions(+) diff --git a/include/asm-generic/pci_iomap.h b/include/asm-generic/pci_iomap.h index 7389c87116a0..b1e17fcee2d0 100644 --- a/include/asm-generic/pci_iomap.h +++ b/include/asm-generic/pci_iomap.h @@ -15,9 +15,13 @@ struct pci_dev; #ifdef CONFIG_PCI /* Create a virtual mapping cookie for a PCI BAR (memory or IO) */ extern void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max); +extern void __iomem *pci_iomap_wc(struct pci_dev *dev, int bar, unsigned long max); extern void __iomem *pci_iomap_range(struct pci_dev *dev, int bar, unsigned long offset, unsigned long maxlen); +extern void __iomem *pci_iomap_wc_range(struct pci_dev *dev, int bar, + unsigned long offset, + unsigned long maxlen); /* Create a virtual mapping cookie for a port on a given PCI device. * Do not call this directly, it exists to make it easier for architectures * to override */ @@ -34,12 +38,22 @@ static inline void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned lon return NULL; } +static inline void __iomem *pci_iomap_wc(struct pci_dev *dev, int bar, unsigned long max) +{ + return NULL; +} static inline void __iomem *pci_iomap_range(struct pci_dev *dev, int bar, unsigned long offset, unsigned long maxlen) { return NULL; } +static inline void __iomem *pci_iomap_wc_range(struct pci_dev *dev, int bar, + unsigned long offset, + unsigned long maxlen) +{ + return NULL; +} #endif #endif /* __ASM_GENERIC_IO_H */ diff --git a/lib/pci_iomap.c b/lib/pci_iomap.c index bcce5f149310..5f5d24d1d53f 100644 --- a/lib/pci_iomap.c +++ b/lib/pci_iomap.c @@ -52,6 +52,51 @@ void __iomem *pci_iomap_range(struct pci_dev *dev, EXPORT_SYMBOL(pci_iomap_range); /** + * pci_iomap_wc_range - create a virtual WC mapping cookie for a PCI BAR + * @dev: PCI device that owns the BAR + * @bar: BAR number + * @offset: map memory at the given offset in BAR + * @maxlen: max length of the memory to map + * + * Using this function you will get a __iomem address to your device BAR. + * You can access it using ioread*() and iowrite*(). These functions hide + * the details if this is a MMIO or PIO address space and will just do what + * you expect from them in the correct way. When possible write combining + * is used. + * + * @maxlen specifies the maximum length to map. If you want to get access to + * the complete BAR from offset to the end, pass %0 here. + * */ +void __iomem *pci_iomap_wc_range(struct pci_dev *dev, + int bar, + unsigned long offset, + unsigned long maxlen) +{ + resource_size_t start = pci_resource_start(dev, bar); + resource_size_t len = pci_resource_len(dev, bar); + unsigned long flags = pci_resource_flags(dev, bar); + + + if (flags & IORESOURCE_IO) + return NULL; + + if (len <= offset || !start) + return NULL; + + len -= offset; + start += offset; + if (maxlen && len > maxlen) + len = maxlen; + + if (flags & IORESOURCE_MEM) + return ioremap_wc(start, len); + + /* What? */ + return NULL; +} +EXPORT_SYMBOL_GPL(pci_iomap_wc_range); + +/** * pci_iomap - create a virtual mapping cookie for a PCI BAR * @dev: PCI device that owns the BAR * @bar: BAR number @@ -70,4 +115,25 @@ void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen) return pci_iomap_range(dev, bar, 0, maxlen); } EXPORT_SYMBOL(pci_iomap); + +/** + * pci_iomap_wc - create a virtual WC mapping cookie for a PCI BAR + * @dev: PCI device that owns the BAR + * @bar: BAR number + * @maxlen: length of the memory to map + * + * Using this function you will get a __iomem address to your device BAR. + * You can access it using ioread*() and iowrite*(). These functions hide + * the details if this is a MMIO or PIO address space and will just do what + * you expect from them in the correct way. When possible write combining + * is used. + * + * @maxlen specifies the maximum length to map. If you want to get access to + * the complete BAR without checking for its length first, pass %0 here. + * */ +void __iomem *pci_iomap_wc(struct pci_dev *dev, int bar, unsigned long maxlen) +{ + return pci_iomap_wc_range(dev, bar, 0, maxlen); +} +EXPORT_SYMBOL_GPL(pci_iomap_wc); #endif /* CONFIG_PCI */