From patchwork Mon Feb 27 15:14:13 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lorenzo Pieralisi X-Patchwork-Id: 732904 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3vX55P1dMCz9sDC for ; Tue, 28 Feb 2017 02:21:13 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751612AbdB0PPf (ORCPT ); Mon, 27 Feb 2017 10:15:35 -0500 Received: from foss.arm.com ([217.140.101.70]:54300 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751387AbdB0PPc (ORCPT ); Mon, 27 Feb 2017 10:15:32 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E55D4139F; Mon, 27 Feb 2017 07:14:55 -0800 (PST) Received: from red-moon.cambridge.arm.com (red-moon.cambridge.arm.com [10.1.206.55]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2530B3F77C; Mon, 27 Feb 2017 07:14:51 -0800 (PST) From: Lorenzo Pieralisi To: linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Lorenzo Pieralisi , Arnd Bergmann , Will Deacon , Bjorn Helgaas , Russell King , Catalin Marinas , Pratyush Anand , Jingoo Han , Mingkai Hu , John Garry , Tanmay Inamdar , Murali Karicheri , Bharat Kumar Gogada , Ray Jui , Wenrui Li , Shawn Lin , Minghuan Lian , Jon Mason , Gabriele Paoloni , Thomas Petazzoni , Joao Pinto , Thierry Reding , Michal Simek , Stanimir Varbanov , Zhou Wang , Roy Zang Subject: [PATCH 02/20] PCI: fix pci_remap_iospace() remap attribute Date: Mon, 27 Feb 2017 15:14:13 +0000 Message-Id: <20170227151436.18698-3-lorenzo.pieralisi@arm.com> X-Mailer: git-send-email 2.10.0 In-Reply-To: <20170227151436.18698-1-lorenzo.pieralisi@arm.com> References: <20170227151436.18698-1-lorenzo.pieralisi@arm.com> Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org According to the PCI local bus specifications (Revision 3.0, 3.2.5), I/O Address space transactions are non-posted. On architectures where I/O space is implemented through a chunk of memory mapped space mapped to PCI address space (ie IA64/ARM/ARM64) the memory mapping for the region backing I/O Address Space transactions determines the I/O transactions attributes (before the transactions actually reaches the PCI bus where it is handled according to the PCI specifications). Current pci_remap_iospace() interface, that is used to map the PCI I/O Address Space into virtual address space, use pgprot_device() as memory attribute for the virtual address mapping, that in some architectures (ie ARM64) provides non-cacheable but write bufferable mappings (ie posted writes), which clash with the non-posted write behaviour for I/O Address Space mandated by the PCI specifications. Update the prot ioremap_page_range() parameter in pci_remap_iospace() to pgprot_noncached to ensure that the virtual mapping backing I/O Address Space guarantee non-posted write transactions issued when addressing I/O Address Space through the MMIO mapping. Signed-off-by: Lorenzo Pieralisi Cc: Arnd Bergmann Cc: Will Deacon Cc: Bjorn Helgaas Cc: Russell King Cc: Catalin Marinas --- drivers/pci/pci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index bd98674..bfb3c6e 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3375,7 +3375,7 @@ int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr) return -EINVAL; return ioremap_page_range(vaddr, vaddr + resource_size(res), phys_addr, - pgprot_device(PAGE_KERNEL)); + pgprot_noncached(PAGE_KERNEL)); #else /* this architecture does not have memory mapped I/O space, so this function should never be called */