From: Grant Edwards <grant.b.edwards@gmail•com>
To: netdev@vger•kernel.org
Subject: Re: net: macb: fail when there's no PHY
Date: Thu, 3 Dec 2020 15:07:58 -0000 (UTC) [thread overview]
Message-ID: <rqav0e$4m3$1@ciao.gmane.io> (raw)
In-Reply-To: 20201203040758.GC2333853@lunn.ch
On 2020-12-03, Andrew Lunn <andrew@lunn•ch> wrote:
>> So I can avoid my local hack to macb_main.c by doing a doing a local
>> hack to macb_main.c?
>
> User space drivers were never supported in any meaningful way. The
> IOCTL call is basically there for mii-tool, and nothing much more.
I probably wouldn't call a single ioctl() to check the link status a
user-space-driver, but I guess that's what it is. If it's good enough
for the mii-tool, it's good enough for me.
> The way to avoid your local hack is to move your drivers into the
> kernel, along side all the other drivers for devices on MDIO busses.
I don't think I can justify the additional effort to devlope and
maintain a custom kern-space driver. We've already got a custom macb
driver, and writing a spearate driver in order to remove a handful of
lines from the macb driver just isn't worth it.
What has confused me all along was Florian Fainelli's post:
>> [I modified the macb driver to support fixed PHY plus mdio access]
>
> That should be unnecessary see below.
>
>> Was there some other way I should have done this with a 5.4 kernel
>> that I was unable to discover?
>
> You should be able to continue having the macb MDIO bus controller
> be registered with no PHY/MDIO devices represented in Device Tree
> such that user-space can continue to use it for ioctl() *and* you
> can point the macb node to a fixed PHY for the purpose of having
> fixed link parameters.
But to do that, I have to modify the macb driver to support a fixed
PHY plus mdio access. What would be the advantage of that modification
over the modification I've already made and tested?
Alternatively, I could write a seperate kernel driver that would "own"
the macb's mdio bus and provide some something equivalent to the
existing SIOC[SG]MIIREG ioctl() calls to access the devices on that
mdio bus.
Thanks for clearing this up for me.
BTW Andrew, we're still shipping plenty of product that running
eCos. :)
--
Grant
next prev parent reply other threads:[~2020-12-03 15:08 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-21 19:59 net: macb: fail when there's no PHY Grant Edwards
2017-09-21 20:05 ` Florian Fainelli
2017-09-21 20:36 ` Grant Edwards
2017-09-21 21:35 ` Brandon Streiff
2017-09-29 7:05 ` Harini Katakam
[not found] ` <CAK=1mW6Gti0QpUjirB6PfMCiQvnDjkbb56pVKkQmpCSkRU6wtA@mail.gmail.com>
2020-12-02 18:10 ` Florian Fainelli
2020-12-02 18:24 ` Grant Edwards
2020-12-02 18:35 ` Andrew Lunn
2020-12-02 19:16 ` Grant Edwards
2020-12-02 21:11 ` Andrew Lunn
2020-12-02 21:23 ` Grant Edwards
2020-12-03 2:39 ` Andrew Lunn
2020-12-03 3:03 ` Grant Edwards
2020-12-03 3:42 ` Florian Fainelli
2020-12-03 3:54 ` Grant Edwards
2020-12-03 4:07 ` Andrew Lunn
2020-12-03 15:07 ` Grant Edwards [this message]
2020-12-03 21:17 ` Andrew Lunn
2020-12-03 21:39 ` Grant Edwards
2020-12-03 21:49 ` Andrew Lunn
2020-12-03 22:20 ` Grant Edwards
2020-12-04 8:28 ` Alexander Dahl
2020-12-04 17:36 ` Andrew Lunn
2020-12-04 16:47 ` Florian Fainelli
2020-12-05 2:52 ` Grant Edwards
2020-12-05 3:06 ` Florian Fainelli
2020-12-03 4:00 ` Andrew Lunn
2020-12-02 18:10 ` Grant Edwards
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