From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [RFC] igb_uio: deprecate iomem and ioport mapping
Date: Fri, 2 Dec 2016 15:47:06 -0800
Message-ID: <20161202154706.3676195c@xeon-e3>
References: <1472696197-37614-1-git-send-email-jianfeng.tan@intel.com>
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Cc: dev@dpdk.org, david.marchand@6wind.com, ferruh.yigit@intel.com
To: Jianfeng Tan <jianfeng.tan@intel.com>
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On Thu,  1 Sep 2016 02:16:37 +0000
Jianfeng Tan <jianfeng.tan@intel.com> wrote:

> Previously in igb_uio, iomem is mapped, and both ioport and io mem
> are recorded into uio framework, which is duplicated and makes the
> code too complex.
> 
> For iomem, DPDK user space code never opens or reads files under
> /sys/pci/bus/devices/xxxx:xx:xx.x/uio/uioY/maps/. Instead,
> /sys/pci/bus/devices/xxxx:xx:xx.x/resourceY are used to map device
> memory.
> 
> For ioport, non-x86 platforms cannot read from files under
> /sys/pci/bus/devices/xxxx:xx:xx.x/uio/uioY/portio/ directly, because
> non-x86 platforms need to map port region for access in user space,
> see non-x86 version pci_uio_ioport_map(). x86 platforms can use the
> the same way as uio_pci_generic.
> 
> This patch deprecates iomem and ioport mapping in igb_uio kernel
> module, and adjusts the iomem implementation in both igb_uio and
> uio_pci_generic:
>   - for x86 platform, get ports info from /proc/ioports;
>   - for non-x86 platform, map and get ports info by pci_uio_ioport_map().
> 
> Note: this will affect those applications who are using files under
> /sys/pci/bus/devices/xxxx:xx:xx.x/uio/uioY/maps/ and
> /sys/pci/bus/devices/xxxx:xx:xx.x/uio/uioY/portio/.
> 
> Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>

What about people using older kernels with the new DPDK EAL and
vice versa?  It makes sense to make igb_uio generic for non DPDK
usage, so it should probably follow the other UIO drivers.