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From:   Vladimir Oltean <olteanv@gmail.com>
Date:   Mon, 1 Jun 2020 12:36:08 +0300
Message-ID: <CA+h21hq4tah3EAdFaLdxTR1JtEaSiZfOFuinwHq-p0AZ+ENesw@mail.gmail.com>
Subject: Re: [PATCH v2] devres: keep both device name and resource name in
 pretty name
To:     Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        bgolaszewski@baylibre.com, mika.westerberg@linux.intel.com,
        efremov@linux.com, ztuowen@gmail.com,
        lkml <linux-kernel@vger.kernel.org>,
        netdev <netdev@vger.kernel.org>
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Hi Sergei,

On Mon, 1 Jun 2020 at 10:51, Sergei Shtylyov
<sergei.shtylyov@cogentembedded.com> wrote:
>
> Hello!
>
> On 31.05.2020 21:07, Vladimir Oltean wrote:
>
> > From: Vladimir Oltean <vladimir.oltean@nxp.com>
> >
> > Sometimes debugging a device is easiest using devmem on its register
> > map, and that can be seen with /proc/iomem. But some device drivers have
> > many memory regions. Take for example a networking switch. Its memory
> > map used to look like this in /proc/iomem:
> >
> > 1fc000000-1fc3fffff : pcie@1f0000000
> >    1fc000000-1fc3fffff : 0000:00:00.5
> >      1fc010000-1fc01ffff : sys
> >      1fc030000-1fc03ffff : rew
> >      1fc060000-1fc0603ff : s2
> >      1fc070000-1fc0701ff : devcpu_gcb
> >      1fc080000-1fc0800ff : qs
> >      1fc090000-1fc0900cb : ptp
> >      1fc100000-1fc10ffff : port0
> >      1fc110000-1fc11ffff : port1
> >      1fc120000-1fc12ffff : port2
> >      1fc130000-1fc13ffff : port3
> >      1fc140000-1fc14ffff : port4
> >      1fc150000-1fc15ffff : port5
> >      1fc200000-1fc21ffff : qsys
> >      1fc280000-1fc28ffff : ana
> >
> > But after the patch in Fixes: was applied, the information is now
> > presented in a much more opaque way:
> >
> > 1fc000000-1fc3fffff : pcie@1f0000000
> >    1fc000000-1fc3fffff : 0000:00:00.5
> >      1fc010000-1fc01ffff : 0000:00:00.5
> >      1fc030000-1fc03ffff : 0000:00:00.5
> >      1fc060000-1fc0603ff : 0000:00:00.5
> >      1fc070000-1fc0701ff : 0000:00:00.5
> >      1fc080000-1fc0800ff : 0000:00:00.5
> >      1fc090000-1fc0900cb : 0000:00:00.5
> >      1fc100000-1fc10ffff : 0000:00:00.5
> >      1fc110000-1fc11ffff : 0000:00:00.5
> >      1fc120000-1fc12ffff : 0000:00:00.5
> >      1fc130000-1fc13ffff : 0000:00:00.5
> >      1fc140000-1fc14ffff : 0000:00:00.5
> >      1fc150000-1fc15ffff : 0000:00:00.5
> >      1fc200000-1fc21ffff : 0000:00:00.5
> >      1fc280000-1fc28ffff : 0000:00:00.5
> >
> > That patch made a fair comment that /proc/iomem might be confusing when
> > it shows resources without an associated device, but we can do better
> > than just hide the resource name altogether. Namely, we can print the
> > device name _and_ the resource name. Like this:
> >
> > 1fc000000-1fc3fffff : pcie@1f0000000
> >    1fc000000-1fc3fffff : 0000:00:00.5
> >      1fc010000-1fc01ffff : 0000:00:00.5 sys
> >      1fc030000-1fc03ffff : 0000:00:00.5 rew
> >      1fc060000-1fc0603ff : 0000:00:00.5 s2
> >      1fc070000-1fc0701ff : 0000:00:00.5 devcpu_gcb
> >      1fc080000-1fc0800ff : 0000:00:00.5 qs
> >      1fc090000-1fc0900cb : 0000:00:00.5 ptp
> >      1fc100000-1fc10ffff : 0000:00:00.5 port0
> >      1fc110000-1fc11ffff : 0000:00:00.5 port1
> >      1fc120000-1fc12ffff : 0000:00:00.5 port2
> >      1fc130000-1fc13ffff : 0000:00:00.5 port3
> >      1fc140000-1fc14ffff : 0000:00:00.5 port4
> >      1fc150000-1fc15ffff : 0000:00:00.5 port5
> >      1fc200000-1fc21ffff : 0000:00:00.5 qsys
> >      1fc280000-1fc28ffff : 0000:00:00.5 ana
> >
> > Fixes: 8d84b18f5678 ("devres: always use dev_name() in devm_ioremap_resource()")
> > Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
> [...]
>
>     You didn't write the version log -- what changed since v1?
>
> MBR, Sergei

The changes in v2 are that I'm checking for memory allocation errors.

Thanks,
-Vladimir