From patchwork Thu Jun 9 18:20:23 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bjorn Helgaas X-Patchwork-Id: 9167709 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id CE79660890 for ; Thu, 9 Jun 2016 18:22:35 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C4FAE28359 for ; Thu, 9 Jun 2016 18:22:35 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BA38C2835B; Thu, 9 Jun 2016 18:22:35 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5599C28359 for ; Thu, 9 Jun 2016 18:22:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933072AbcFISUc (ORCPT ); Thu, 9 Jun 2016 14:20:32 -0400 Received: from mail.kernel.org ([198.145.29.136]:58884 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933071AbcFISU2 (ORCPT ); Thu, 9 Jun 2016 14:20:28 -0400 Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 7C9CB202FE; Thu, 9 Jun 2016 18:20:26 +0000 (UTC) Received: from localhost (173-27-161-33.client.mchsi.com [173.27.161.33]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 863362015A; Thu, 9 Jun 2016 18:20:25 +0000 (UTC) Subject: [PATCH v1 2/3] powerpc/pci: Remove __pci_mmap_set_pgprot() To: Yinghai Lu , Benjamin Herrenschmidt , Michal Simek , Paul Mackerras , Michael Ellerman From: Bjorn Helgaas Cc: linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Date: Thu, 09 Jun 2016 13:20:23 -0500 Message-ID: <20160609182023.13455.82564.stgit@bhelgaas-glaptop2.roam.corp.google.com> In-Reply-To: <20160609181102.13455.33593.stgit@bhelgaas-glaptop2.roam.corp.google.com> References: <20160609181102.13455.33593.stgit@bhelgaas-glaptop2.roam.corp.google.com> User-Agent: StGit/0.16 MIME-Version: 1.0 X-Virus-Scanned: ClamAV using ClamSMTP Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Yinghai Lu The powerpc-specific __pci_mmap_set_pgprot() does two things: 1) Disables write combining for I/O port space mappings This only affects procfs mappings. The pci_mmap_resource() sysfs path only requests write combining for resources with IORESOURCE_PREFETCH set, which doesn't include I/O resources. The only way to request write combining for I/O port space mappings was via the PCIIOC_WRITE_COMBINE ioctl and the proc_bus_pci_mmap() path, and we recently changed that path to ignore write combining for I/O, so this code in powerpc is no longer needed. 2) Automatically enables write combining for mappings of prefetchable resources, even if not requested by the user Both procfs (via PCIIOC_MMAP_IS_MEM and PCIIOC_WRITE_COMBINE ioctls) and sysfs (via "resourceN_wc" files, which are created for resources with IORESOURCE_PREFETCH) provide ways for the user to map PCI memory space with write combining. Users that desire write combining should use one of those ways instead of relying on powerpc-specific behavior. Remove the powerpc-specific __pci_mmap_set_pgprot(). The user-visible effect of this change is that users mapping prefetchable PCI memory space via procfs without PCIIOC_WRITE_COMBINE or via sysfs "resourceN" (not "resourceN_wc") will get regular uncacheable mappings instead of the write combining mappings they used to get. The new behavior matches the behavior on all other arches that support write combining mapping. [bhelgaas: changelog] Signed-off-by: Yinghai Lu Signed-off-by: Bjorn Helgaas --- arch/powerpc/kernel/pci-common.c | 37 ++++--------------------------------- 1 file changed, 4 insertions(+), 33 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c index 0f7a60f..8c6beb0 100644 --- a/arch/powerpc/kernel/pci-common.c +++ b/arch/powerpc/kernel/pci-common.c @@ -356,36 +356,6 @@ static struct resource *__pci_mmap_make_offset(struct pci_dev *dev, } /* - * Set vm_page_prot of VMA, as appropriate for this architecture, for a pci - * device mapping. - */ -static pgprot_t __pci_mmap_set_pgprot(struct pci_dev *dev, struct resource *rp, - pgprot_t protection, - enum pci_mmap_state mmap_state, - int write_combine) -{ - - /* Write combine is always 0 on non-memory space mappings. On - * memory space, if the user didn't pass 1, we check for a - * "prefetchable" resource. This is a bit hackish, but we use - * this to workaround the inability of /sysfs to provide a write - * combine bit - */ - if (mmap_state != pci_mmap_mem) - write_combine = 0; - else if (write_combine == 0) { - if (rp->flags & IORESOURCE_PREFETCH) - write_combine = 1; - } - - /* XXX would be nice to have a way to ask for write-through */ - if (write_combine) - return pgprot_noncached_wc(protection); - else - return pgprot_noncached(protection); -} - -/* * This one is used by /dev/mem and fbdev who have no clue about the * PCI device, it tries to find the PCI device first and calls the * above routine @@ -458,9 +428,10 @@ int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma, return -EINVAL; vma->vm_pgoff = offset >> PAGE_SHIFT; - vma->vm_page_prot = __pci_mmap_set_pgprot(dev, rp, - vma->vm_page_prot, - mmap_state, write_combine); + if (write_combine) + vma->vm_page_prot = pgprot_noncached_wc(vma->vm_page_prot); + else + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); ret = remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, vma->vm_end - vma->vm_start, vma->vm_page_prot);