From: Sudeep Dutt <sudeep.dutt@intel.com>
To: Vinod Koul <vinod.koul@intel.com>
Cc: Ashutosh Dixit <ashutosh.dixit@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Dan Williams <dan.j.williams@intel.com>,
linux-kernel@vger.kernel.org, Nikhil Rao <nikhil.rao@intel.com>,
Siva Yerramreddy <yshivakrishna@gmail.com>,
Sudeep Dutt <sudeep.dutt@intel.com>
Subject: Re: [PATCH char-misc-next 11/19] dma: Add support to program MIC x100 status descriptiors
Date: Fri, 21 Aug 2015 09:14:13 -0700 [thread overview]
Message-ID: <1440173653.115234.123.camel@localhost> (raw)
In-Reply-To: <20150821082939.GL13546@localhost>
On Fri, 2015-08-21 at 13:59 +0530, Vinod Koul wrote:
> On Thu, Aug 20, 2015 at 10:30:50AM -0700, Sudeep Dutt wrote:
> > On Thu, 2015-08-20 at 10:50 +0530, Vinod Koul wrote:
> > > On Mon, Jul 27, 2015 at 04:58:17PM -0700, Ashutosh Dixit wrote:
>
> > > > + /*
> > > > + * This is a hack to program status descriptor since
> > > > + * DMA engine API doesn't have support for this.
> > > > + */
> > > what do you mean by programming status descriptor, what do you need to
> > > program?
> > >
> >
> > The MIC X100 DMA engine has a special status descriptor which writes an
> > 8 byte immediate data value to a destination address. It is used to
> > signal completion of all DMA descriptors prior to the status descriptor.
> > The DMA engine API does not allow drivers to pass a 8 byte value. We are
> > allowed to pass a source physical address but we cannot determine the
> > source value within the DMA driver using that information specifically
> > with the IOMMU enabled. We have added this workaround so that we can
> > program this special status update descriptor without making any changes
> > to the DMA engine API.
> I think this is a special case so you should export an API and let client
> program using that API.
>
Sounds good. We will export a new API from the MIC X100 DMA driver in
the next revision of this patch series.
Thanks for the review!
Sudeep Dutt
next prev parent reply other threads:[~2015-08-21 16:15 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-27 23:52 [PATCH char-misc-next 00/19] misc: mic: Enable COSM and remaining SCIF functionality Ashutosh Dixit
2015-07-27 23:53 ` [PATCH char-misc-next 01/19] misc: mic: SCIF poll Ashutosh Dixit
2015-07-27 23:53 ` [PATCH char-misc-next 02/19] misc: mic: Add support for kernel mode SCIF clients Ashutosh Dixit
2015-07-27 23:54 ` [PATCH char-misc-next 03/19] misc: mic: MIC COSM bus Ashutosh Dixit
2015-07-27 23:54 ` [PATCH char-misc-next 04/19] misc: mic: Coprocessor State Management (COSM) driver Ashutosh Dixit
2015-07-27 23:55 ` [PATCH char-misc-next 05/19] misc: mic: COSM SCIF server Ashutosh Dixit
2015-07-27 23:55 ` [PATCH char-misc-next 06/19] misc: mic: COSM client driver Ashutosh Dixit
2015-07-27 23:55 ` [PATCH char-misc-next 07/19] misc: mic: Remove COSM functionality from the MIC host driver Ashutosh Dixit
2015-07-27 23:55 ` [PATCH char-misc-next 08/19] misc: mic: Remove COSM functionality from the MIC card driver Ashutosh Dixit
2015-07-27 23:56 ` [PATCH char-misc-next 09/19] misc: mic: Update MIC host daemon with COSM changes Ashutosh Dixit
2015-07-27 23:57 ` [PATCH char-misc-next 10/19] lib: convert iova.c into a library Ashutosh Dixit
2015-07-28 10:03 ` Joerg Roedel
2015-07-28 10:41 ` Robin Murphy
2015-07-28 14:38 ` David Woodhouse
2015-07-28 17:01 ` Sudeep Dutt
2015-07-28 20:40 ` Andrew Morton
2015-07-31 0:31 ` Ashutosh Dixit
2015-07-27 23:58 ` [PATCH char-misc-next 11/19] dma: Add support to program MIC x100 status descriptiors Ashutosh Dixit
2015-08-20 5:20 ` Vinod Koul
2015-08-20 17:30 ` Sudeep Dutt
2015-08-21 8:29 ` Vinod Koul
2015-08-21 16:14 ` Sudeep Dutt [this message]
2015-07-27 23:59 ` [PATCH char-misc-next 12/19] misc: mic: SCIF RMA header file and IOCTL changes Ashutosh Dixit
2015-07-27 23:59 ` [PATCH char-misc-next 13/19] misc: mic: SCIF RMA header file Ashutosh Dixit
2015-07-27 23:59 ` [PATCH char-misc-next 14/19] misc: mic: SCIF memory registration and unregistration Ashutosh Dixit
2015-07-28 0:00 ` [PATCH char-misc-next 15/19] misc: mic: SCIF RMA list operations Ashutosh Dixit
2015-07-28 0:00 ` [PATCH char-misc-next 16/19] misc: mic: SCIF remote memory map/unmap interface Ashutosh Dixit
2015-07-28 0:00 ` [PATCH char-misc-next 17/19] misc: mic: SCIF DMA and CPU copy interface Ashutosh Dixit
2015-07-28 0:00 ` [PATCH char-misc-next 18/19] misc: mic: SCIF fence Ashutosh Dixit
2015-07-28 0:01 ` [PATCH char-misc-next 19/19] misc: mic: SCIF RMA nodeqp and minor miscellaneous changes Ashutosh Dixit
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