From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
To: Florian Fainelli <f.fainelli@gmail.com>,
David Miller <davem@davemloft.net>,
vivien.didelot@savoirfairelinux.com
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel@savoirfairelinux.com
Subject: Re: [PATCH] net: mdio-gpio: support access that may sleep
Date: Fri, 24 Apr 2015 20:42:49 +0300 [thread overview]
Message-ID: <553A8099.5000705@cogentembedded.com> (raw)
In-Reply-To: <553A7F28.4040109@gmail.com>
On 04/24/2015 08:36 PM, Florian Fainelli wrote:
>>>>> Some systems using mdio-gpio may use gpio on message based busses,
>>>>> which
>>>>> require sleeping (e.g. gpio from an I2C I/O expander).
>>>>> Since this driver does not use IRQ handler, it is safe to use the
>>>>> _cansleep suffixed gpio accessors.
>>>>> Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
>>>> Since this is down underneath the layer of an MII bus, you cannot
>>>> universally say that these routines are always called in a sleepable
>>>> context.
>>>> The PHY layer, and the driver itself above that, might call these
>>>> routines from timers, interruptes etc.
>>> The PHY library calls these routines from its state machine workqueue
>>> for that reason, or from process context (when invoked via ethtool
>>> ioctl). The only special case is phy_mac_interrupt() which is callable
>>> from interrupt context,
>> It is not (as we have discussed recently) -- cancel_work_sync() may
>> sleep.
> True, but that does not invalidate my comment, I meant to write that
> this is the only function that you *might* potentially want to call from
> interrupt context,
Sure, I did want that. :-)
> and yet it does not trigger low-level I/O accesses to
> the underlying MDIO bus, but instead uses the PHY library state machine
> workqueue to do that.
That's so.
> Thanks for the reminder though, that needs fixing ;)
Hopefully it's fixable... I had to use GPIO interrupt for AVB_PHY_INT pin
since I didn't want to create a thread just to call phy_mac_interrupt().
> --
> Florian
WBR, Sergei
prev parent reply other threads:[~2015-04-24 17:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-22 17:06 [PATCH] net: mdio-gpio: support access that may sleep Vivien Didelot
2015-04-24 15:04 ` David Miller
2015-04-24 15:56 ` Florian Fainelli
2015-04-24 16:01 ` David Miller
2015-04-24 16:19 ` Florian Fainelli
2015-04-24 16:25 ` David Miller
2015-04-24 17:25 ` Sergei Shtylyov
2015-04-24 17:36 ` Florian Fainelli
2015-04-24 17:42 ` Sergei Shtylyov [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=553A8099.5000705@cogentembedded.com \
--to=sergei.shtylyov@cogentembedded.com \
--cc=davem@davemloft.net \
--cc=f.fainelli@gmail.com \
--cc=kernel@savoirfairelinux.com \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=vivien.didelot@savoirfairelinux.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).