Linux Serial subsystem development
 help / color / mirror / Atom feed
From: "Piotr Król" <piotr.krol@3mdeb.com>
To: linux-serial@vger.kernel.org
Cc: jslaby@suse.cz, gregkh@linuxfoundation.org, linux@arm.linux.org.uk
Subject: amba-pl011 complains about DMA for bcm2835 where it is not supported
Date: Tue, 28 Oct 2014 00:44:31 +0100	[thread overview]
Message-ID: <20141027234430.GA1788@haysend> (raw)

Hi all,
according to BCM2835 ARM Peripherals spec DMA is optional functionality
for ARM PL011 UART and it is not supported on this SoC. It looks like
amba-pl011 search for device tree property (dma-names) unconditionally,
what leads to error message:

of_dma_request_slave_channel: dma-names property of node '/soc/uart@7e201000' missing or empty
uart-pl011 20201000.uart: no DMA platform data

I assume that if it is possible that amba-pl011 can be without DMA we
should check if DMA is supported and then try to read properties. Is
there any known method for checking dma support ? If yes that I would be
glad for any pointers.

Let me know if I should ignore/accept this error message or there is
some code fix needed.

Thanks,
Piotr Król
~
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

             reply	other threads:[~2014-10-28  0:03 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-27 23:44 Piotr Król [this message]
2014-10-27 23:59 ` amba-pl011 complains about DMA for bcm2835 where it is not supported Russell King - ARM Linux
2014-10-28  0:09   ` Piotr Król
2014-10-28  0:16     ` Russell King - ARM Linux

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=20141027234430.GA1788@haysend \
    --to=piotr.krol@3mdeb.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=jslaby@suse.cz \
    --cc=linux-serial@vger.kernel.org \
    --cc=linux@arm.linux.org.uk \
    /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