From: lauri.hintsala@bluegiga•com (Lauri Hintsala)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 2/3] serial: mxs-auart: add the DMA support for mx28
Date: Thu, 15 Nov 2012 09:22:39 +0200 [thread overview]
Message-ID: <50A4983F.8080407@bluegiga.com> (raw)
In-Reply-To: <50A45F83.1010009@freescale.com>
Hi,
On 11/15/2012 05:20 AM, Huang Shijie wrote:
> ? 2012?11?13? 17:42, Lauri Hintsala ??:
>> Hi Huang,
>>
>> DMA support doesn't work with latest stable v3.6.5 or development
>> 3.7-rc5 kernels. I get following error message when I open the serial
>> port /dev/ttyAPP0:
>>
>> [ 48.730000] mxs-auart 8006a000.serial: step 1 error
>> [ 48.750000] mxs-auart 8006a000.serial: We can not start up the DMA.
>>
> I tested this patch set in imx28-evk board Rev C with linux-next-20121114.
> it works fine.
>
> Maybe you can try the linux-next code.
I tested linux-next-20121114 on apx4devkit (imx28 based device) and I
got the same error message:
# stty -F /dev/ttyAPP0 crtscts; microcom /dev/ttyAPP0 -s 115200
[ 133.710000] mxs-auart 8006a000.serial: step 1 error
[ 133.720000] mxs-auart 8006a000.serial: We can not start up the DMA.
> About the flow control:
> If we do not enable the HW flow control, the data may lost. And I do not
> know how to handle with the Xon/Xoff when the DMA is supported.
I do not have the answer but it is already implemented in Freescale's
reference kernel
(http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/tree/drivers/serial/mxs-auart.c?h=imx_2.6.35_11.09.01).
So I think it is possible to handle all data without HW flow control.
Best Regards,
Lauri Hintsala
next prev parent reply other threads:[~2012-11-15 7:22 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-24 10:27 [PATCH v2 0/3] serial: mxs-auart: add DMA support for auart in mx28 Huang Shijie
2012-10-24 10:27 ` [PATCH v2 1/3] serial: mxs-auart: distinguish the different SOCs Huang Shijie
2012-10-24 10:27 ` [PATCH v2 2/3] serial: mxs-auart: add the DMA support for mx28 Huang Shijie
2012-10-25 4:18 ` Vinod Koul
2012-10-25 5:50 ` Huang Shijie
2012-10-25 6:07 ` Vinod Koul
2012-10-25 9:15 ` Huang Shijie
2012-10-25 11:08 ` Vinod Koul
2012-11-05 3:16 ` Huang Shijie
2012-11-13 9:42 ` Lauri Hintsala
2012-11-15 3:20 ` Huang Shijie
2012-11-15 7:22 ` Lauri Hintsala [this message]
2012-11-15 9:11 ` Huang Shijie
2012-11-15 11:51 ` Lauri Hintsala
2012-10-24 10:27 ` [PATCH v2 3/3] ARM: dts: enable dma support for auart0 in mx28 Huang Shijie
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