From: Sinan Kaya <okaya@codeaurora.org>
To: Vinod Koul <vinod.koul@intel.com>
Cc: dmaengine@vger.kernel.org, timur@codeaurora.org,
cov@codeaurora.org, jcm@redhat.com, agross@codeaurora.org,
arnd@arndb.de, linux-arm-msm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH V7 3/3] dma: add Qualcomm Technologies HIDMA channel driver
Date: Wed, 2 Dec 2015 14:04:05 -0500 [thread overview]
Message-ID: <565F40A5.2040701@codeaurora.org> (raw)
In-Reply-To: <565E0E1D.1040505@codeaurora.org>
On 12/1/2015 4:16 PM, Sinan Kaya wrote:
>>>> >>>
>>>>> >>>> +static enum dma_status hidma_tx_status(struct dma_chan *dmach,
>>>>> >>>> + dma_cookie_t cookie, struct dma_tx_state *txstate)
>>>>> >>>> +{
>>>>> >>>> + struct hidma_chan *mchan = to_hidma_chan(dmach);
>>>>> >>>> + enum dma_status ret;
>>>>> >>>> +
>>>>> >>>> + if (mchan->paused)
>>>>> >>>> + ret = DMA_PAUSED;
>>>> >>>
>>>> >>> This is not quite right. The status query is for a descriptor and NOT for
>>>> >>> channel. Here if the descriptor queried was running then it would be paused
>>>> >>> for the rest pending txn, it would be DMA_IN_PROGRESS.
>>> >>
>>> >> The channel can be paused by the hypervisor. If it is paused, then no
>>> >> other transaction will go through including the pending requests. That's
>>> >> why, I'm checking the state first.
>> >
>> > You are missing the point. Channel can be paused, yes but the descriptor
>> > is in queue and is not paused. The descriptor running is paused, yes.
>> > There is subtle difference between these
> I'll follow your recommendation. PAUSE for the currently active
> descriptor and DMA_IN_PROGRESS for the rest.
>
I'm now confused.
I looked at several DMA driver implementations.
1. They call dma_cookie_status function to see if the job is done.
2. If done, they return right ahead.
3. Otherwise, dma_cookie_status returns DMA_IN_PROGRESS.
4. Next the code checks if the channel is paused and return value is
DMA_IN_PROGRESS. The code changes return code to DMA_PAUSED.
Whereas, I was returning paused first before even checking if the
descriptor is done. Are you OK with the sequence 1..4 above?
--
Sinan Kaya
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a
Linux Foundation Collaborative Project
next prev parent reply other threads:[~2015-12-02 19:04 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-23 2:28 [PATCH V7 0/3] dma: add Qualcomm Technologies HIDMA driver Sinan Kaya
2015-11-23 2:28 ` [PATCH V7 1/3] dma: qcom_bam_dma: move to qcom directory Sinan Kaya
2015-11-25 21:42 ` Andy Gross
2015-11-28 15:06 ` Sinan Kaya
2015-11-23 2:28 ` [PATCH V7 2/3] dma: add Qualcomm Technologies HIDMA management driver Sinan Kaya
2015-11-23 18:06 ` Andy Shevchenko
2015-11-23 18:49 ` Sinan Kaya
2015-11-30 8:21 ` Vinod Koul
2015-11-30 14:42 ` Sinan Kaya
2015-12-01 3:17 ` Vinod Koul
2015-12-02 4:57 ` Sinan Kaya
2015-12-05 7:58 ` Vinod Koul
2015-12-08 14:36 ` Sinan Kaya
2015-11-23 2:28 ` [PATCH V7 3/3] dma: add Qualcomm Technologies HIDMA channel driver Sinan Kaya
2015-11-30 8:59 ` Vinod Koul
2015-11-30 20:06 ` Sinan Kaya
2015-12-01 11:34 ` Vinod Koul
2015-12-01 21:16 ` Sinan Kaya
2015-12-02 19:04 ` Sinan Kaya [this message]
2015-12-05 8:00 ` Vinod Koul
2015-12-08 14:33 ` Sinan Kaya
2015-12-10 20:10 ` Sinan Kaya
2015-12-11 9:35 ` Vinod Koul
2015-12-17 23:52 ` Sinan Kaya
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=565F40A5.2040701@codeaurora.org \
--to=okaya@codeaurora.org \
--cc=agross@codeaurora.org \
--cc=arnd@arndb.de \
--cc=cov@codeaurora.org \
--cc=dmaengine@vger.kernel.org \
--cc=jcm@redhat.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=timur@codeaurora.org \
--cc=vinod.koul@intel.com \
/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).