From mboxrd@z Thu Jan 1 00:00:00 1970 From: Santosh Shukla Subject: Re: [PATCH] eal: map io resources for non x86 architectures Date: Thu, 17 Dec 2015 15:32:19 +0530 Message-ID: References: <1450269064-23608-1-git-send-email-david.marchand@6wind.com> <20151216124834.GR29571@yliu-dev.sh.intel.com> <20151217093847.GB29571@yliu-dev.sh.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: dev@dpdk.org To: Yuanhan Liu Return-path: Received: from mail-pf0-f172.google.com (mail-pf0-f172.google.com [209.85.192.172]) by dpdk.org (Postfix) with ESMTP id 7ACCD11A2 for ; Thu, 17 Dec 2015 11:02:20 +0100 (CET) Received: by mail-pf0-f172.google.com with SMTP id 68so28337191pfc.1 for ; Thu, 17 Dec 2015 02:02:20 -0800 (PST) In-Reply-To: List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Thu, Dec 17, 2015 at 3:31 PM, Santosh Shukla wrote: > On Thu, Dec 17, 2015 at 3:08 PM, Yuanhan Liu > wrote: >> On Wed, Dec 16, 2015 at 07:21:55PM +0530, Santosh Shukla wrote: >>> On Wed, Dec 16, 2015 at 6:18 PM, Yuanhan Liu >>> wrote: >>> > On Wed, Dec 16, 2015 at 01:31:04PM +0100, David Marchand wrote: >>> >> x86 requires a special set of instructions to access ioports, but other >>> >> architectures let you remap io resources. >>> >> So let eal remap io resources by accepting IORESOURCE_IO flag for >>> >> architectures other than x86. >>> > >>> > One question: this patch could be a replacement of the igbuio_iomap patch >>> > from Santosh? If so, I like it: It's more elegant. >>> > >>> > --yliu >>> > >>> >>> I did tried similar in past but not in parse_sysfs (such that >>> mem.resource_addr to accept IO_RESOURCE_IO types) and observed that >>> pci_map_resource not able to map address hence segfault at tespmd >>> initialization. >>> >>> i was getting these: >>> EAL: pci_map_resource(): cannot mmap(19, 0x7fa5c00000, 0x20, 0x0): >>> Invalid argument (0xffffffffffffffff) >> >> That's because ARM (at least the kernel) doesn't allow an IO map: >> >> arch/arm/kernel/bios32.c >> ------------------------ >> 618 int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma, >> 619 enum pci_mmap_state mmap_state, int write_combine) >> 620 { >> 621 if (mmap_state == pci_mmap_io) >> 622 return -EINVAL; >> >> And with a quick glimpse of powerpc, I see no such limitation. Hence, >> this peice of code may work only on Powerpc platform (and maybe a few >> others we don't care). >> >> So, apparently, this will not work for ARM. >> > > Right and I did shared detailed explanation on why it wont work on > this link [1], infact this patch shouldn;t work for mips too. > > As I mentioned earlier I did tried similar approach and so to get > everything working like iomem is currently in dpdk; we need to add > something like pci_remap_iospace --> ioremap_page_range() but this api > not really pci_mmap_page_range types. user need to write more code on > top so to use this api efficiently, also this api looks like meant to > use by arch file only in kernel space. > > missed link; [1] http://dpdk.org/dev/patchwork/patch/9365/ >> --yliu