From: Michal Simek <michal.simek@xilinx.com>
To: Rob Herring <robh+dt@kernel.org>, Michal Simek <michal.simek@xilinx.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Michal Simek <monstr@monstr.eu>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
<devicetree@vger.kernel.org>, Jiri Slaby <jslaby@suse.com>,
"open list:SERIAL DRIVERS" <linux-serial@vger.kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] of: base: Change logic in of_alias_get_alias_list()
Date: Tue, 9 Oct 2018 09:18:53 +0200 [thread overview]
Message-ID: <2bbc70c9-21b0-dfa2-ddea-554afb2c4f89@xilinx.com> (raw)
In-Reply-To: <CAL_JsqLNMM6mS1oy1voDAibRk1Srcp7i8e3pESTnM957Rxp4ow@mail.gmail.com>
On 8.10.2018 17:07, Rob Herring wrote:
> On Mon, Oct 8, 2018 at 7:19 AM Michal Simek <michal.simek@xilinx.com> wrote:
>>
>> Check compatible string first before setting up bit in bitmap to also
>> cover cases that allocated bitfield is not big enough.
>> Show warning about it but let driver to continue to work with allocated
>> bitfield to keep at least some devices (included console which
>> is commonly close to serial0) to work.
>>
>> Fixes: b1078c355d76 ("of: base: Introduce of_alias_get_alias_list() to check alias IDs")
>> Fixes: ae1cca3fa347 ("serial: uartps: Change uart ID port allocation")
>> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
>> ---
>>
>> I have looked at it and I don't think there should be necessary to
>> report error immediately back with partially initialized bitfield.
>> The reason is that still there could be a console device which is most
>> likely below that max limit and it is worth to return at least that nbits
>> properly filled.
>> It will also enable cases that you can still continue to use aliases
>> higher then fields prepared for devices without alias.
>
> Seems reasonable. Plus if you had a new dtb which added an alias
> greater than what the OS version supports, you would break that
> system.
I was checking that with our uart ps driver before I send this patch and
I found out that there is no reason not to support these cases.
Driver will simply find out ids which are free and ready for devices
which don't have alias.
>
>>
>> To be fixed patches are present in tty-next branch.
>>
>> ---
>> drivers/of/base.c | 22 ++++++++++++----------
>> drivers/tty/serial/xilinx_uartps.c | 2 +-
>> 2 files changed, 13 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/of/base.c b/drivers/of/base.c
>> index 908de45f966b..0b9611e196d1 100644
>> --- a/drivers/of/base.c
>> +++ b/drivers/of/base.c
>> @@ -1953,13 +1953,15 @@ int of_alias_get_id(struct device_node *np, const char *stem)
>> * The function travels the lookup table to record alias ids for the given
>> * device match structures and alias stem.
>> *
>> - * Return: 0 or -ENOSYS when !CONFIG_OF
>> + * Return: 0 or -ENOSYS when !CONFIG_OF or
>> + * -EINVAL if alias ID is greater then allocated nbits
>
> I think EOVERFLOW or ERANGE would be better as those are less common
> and I take EINVAL as the caller made an error.
That's a good point I was also thinking if EINVAL is good reaction on
this case. I will use EOVERFLOW if there is no issue with it.
Thanks,
Michal
prev parent reply other threads:[~2018-10-09 7:19 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-08 12:19 [PATCH] of: base: Change logic in of_alias_get_alias_list() Michal Simek
2018-10-08 15:07 ` Rob Herring
2018-10-09 7:18 ` Michal Simek [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=2bbc70c9-21b0-dfa2-ddea-554afb2c4f89@xilinx.com \
--to=michal.simek@xilinx.com \
--cc=devicetree@vger.kernel.org \
--cc=frowand.list@gmail.com \
--cc=geert@linux-m68k.org \
--cc=gregkh@linuxfoundation.org \
--cc=jslaby@suse.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-serial@vger.kernel.org \
--cc=monstr@monstr.eu \
--cc=robh+dt@kernel.org \
/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).