From mboxrd@z Thu Jan 1 00:00:00 1970
Return-Path: <sshukla@mvista.com>
Received: from mail-pa0-f44.google.com (mail-pa0-f44.google.com
[209.85.220.44]) by dpdk.org (Postfix) with ESMTP id 6F1C868A5
for <dev@dpdk.org>; Thu, 17 Dec 2015 11:21:21 +0100 (CET)
Received: by mail-pa0-f44.google.com with SMTP id q3so20126831pav.3
for <dev@dpdk.org>; Thu, 17 Dec 2015 02:21:21 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=mvista-com.20150623.gappssmtp.com; s=20150623;
h=mime-version:in-reply-to:references:date:message-id:subject:from:to
:cc:content-type;
bh=T88YUfY6bwAe0hUM4F6HpliA+2j8/5132tvZS/nNfWA=;
b=fQPKzb+0bj4Fsawu/ocfyGUHwSp/hNa38btRxUNfl6RhRnSDV9wr5AaunphtvqGiHR
7MWnElKczyeBprTr5rLcAfcH5fqBKlgxy5jOUE4CESNRse6gH/JpwILZlwiq7jEIb3su
uSlKq1lQw8N3wHyjLXJ18ce9ob96fNpDt5Fu16ffM7rol73hD0M2BK3wke/RprTLHkTN
dxaCEyIiRjlfTRAxA1PdrieFmZntZPFwCQk1auOjsBaYlTWOaE8LaBcbOziGP8UgkIAF
t+OAYRsYlCX7fZK97h1KIaYKSdwJWGAyrJXT0wjuX/MDMpxBpEuJZ6M83sg67pO0FuYK
5TFQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=1e100.net; s=20130820;
h=x-gm-message-state:mime-version:in-reply-to:references:date
:message-id:subject:from:to:cc:content-type;
bh=T88YUfY6bwAe0hUM4F6HpliA+2j8/5132tvZS/nNfWA=;
b=V3MxPT5jgSdbYUJBj6vIUrkpHd18hiVitJZdhO0iBPnk4tEgH6fsaXhydhsJGTUIog
+soeT4zK7pm1+53xEu5GmljK58VCVajTl+o+nIevfCR8ajfuAsqXjadOd2KilfXa7Rw8
u+nrdtoiOqBhkklkBYv3LuQZ9jb2/kXhnPAVA2BlN4C23HB9L0eLWZf3ECd3m3JE7sT/
QqMyus2iq10QdesTx+DFkrfLuwR9jbjipuM/LqQTdAeenOuvj/ufBbGXTdIxNX9nFxSu
uLFiCm+lva6x0plIV5+xzN9FOATERrgPFz9FuyyvjWgBkyDRdxL/Jmbt0FIZSiRzS4lk
BXwg==
X-Gm-Message-State: ALoCoQlxWJ4yybF0fYzNK0sPg0p1GoeW+vFBSiarDEi8KSXu9HqD5eVIkZFVjvHvV+gxyPYVb9aJmhgGdkjZUeDZcCEELtBGp9QtOVTvADbDwsNFl+PpJEE=
MIME-Version: 1.0
X-Received: by 10.66.140.79 with SMTP id re15mr68926162pab.127.1450347680764;
Thu, 17 Dec 2015 02:21:20 -0800 (PST)
Received: by 10.66.13.233 with HTTP; Thu, 17 Dec 2015 02:21:20 -0800 (PST)
In-Reply-To: <2241331.HNmyzf8foi@xps13>
References: <CAAyOgsaMO7V1K8Yxh=Zf-E4iodDevMFG+rRBPgZXBysca9JopA@mail.gmail.com>
<CAAyOgsbbb2O9RX+boPQkEWuBJ2p402YH-dBhk5oD1hUi9A0tXQ@mail.gmail.com>
<CAAyOgsboGTcQ4CyksMpA400KkWDQSDbU490E9yQan4HMCzsxFg@mail.gmail.com>
<2241331.HNmyzf8foi@xps13>
Date: Thu, 17 Dec 2015 15:51:20 +0530
Message-ID: <CAAyOgsad_+fD5yNB83UG_JwBhYhJLWoLHCiH0XQb3pxb3AEcdg@mail.gmail.com>
From: Santosh Shukla <sshukla@mvista.com>
To: Thomas Monjalon <thomas.monjalon@6wind.com>
Content-Type: text/plain; charset=UTF-8
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH] eal: map io resources for non x86
architectures
X-BeenThere: dev@dpdk.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: patches and discussions about DPDK <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
<mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
<mailto:dev-request@dpdk.org?subject=subscribe>
X-List-Received-Date: Thu, 17 Dec 2015 10:21:21 -0000
On Thu, Dec 17, 2015 at 3:44 PM, Thomas Monjalon
<thomas.monjalon@6wind.com> wrote:
> Hi,
>
> 2015-12-17 15:37, Santosh Shukla:
>> On Thu, Dec 17, 2015 at 3:32 PM, Santosh Shukla <sshukla@mvista.com> wrote:
>> > On Thu, Dec 17, 2015 at 3:31 PM, Santosh Shukla <sshukla@mvista.com> wrote:
>> >> On Thu, Dec 17, 2015 at 3:08 PM, Yuanhan Liu
>> >> <yuanhan.liu@linux.intel.com> 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
>> >>>> <yuanhan.liu@linux.intel.com> 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/
>> >
>>
>> IMO, it is worth keeping one special device file who could work across
>> archs like arm/arm64/powerpc and others, who could map iopci bar to
>> dpdk user-space. also this approach has no kernel version dependency
>> too. BTW; I did mentioned in second approach in to add /dev/ioport
>> interface in drivers/char/mem.c which could read more than byte in one
>> single operation, but that has kernel dependency. However that
>> approach too is arch agnostic.
>
> Your first approach use an out-of-tree kernel module (igb_uio), so we cannot
> really say there is no kernel dependency.
Agree but I mentioned kernel __version__ dependency.
> We should try to remove the need for any out-of-tree kernel module.
> That's why the Linux upstream approach is a better solution.
IIUC, your suggesting archs like arm/arm64 to support io_mappe_io in
pci_mmap_page_range()?