dmaengine Archive on lore.kernel.org
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From: Jon Hunter <jonathanh@nvidia.com>
To: Dmitry Osipenko <digetx@gmail.com>,
	Peter Ujfalusi <peter.ujfalusi@ti.com>,
	Sameer Pujar <spujar@nvidia.com>, Vinod Koul <vkoul@kernel.org>
Cc: <dan.j.williams@intel.com>, <tiwai@suse.com>,
	<dmaengine@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<sharadg@nvidia.com>, <rlokhande@nvidia.com>,
	<dramesh@nvidia.com>, <mkumard@nvidia.com>,
	linux-tegra <linux-tegra@vger.kernel.org>
Subject: Re: [PATCH] [RFC] dmaengine: add fifo_size member
Date: Thu, 6 Jun 2019 15:36:03 +0100
Message-ID: <e24a26d8-6355-bac0-eeba-8d8ce8d5f985@nvidia.com> (raw)
In-Reply-To: <2eab4777-79b8-0aea-c22f-ac9d11284889@nvidia.com>


On 06/06/2019 15:26, Jon Hunter wrote:

...

>>> If I understood everything correctly, the FIFO buffer is shared among
>>> all of the ADMA clients and hence it should be up to the ADMA driver to
>>> manage the quotas of the clients. So if there is only one client that
>>> uses ADMA at a time, then this client will get a whole FIFO buffer, but
>>> once another client starts to use ADMA, then the ADMA driver will have
>>> to reconfigure hardware to split the quotas.
>>>
>>
>> You could also simply hardcode the quotas per client in the ADMA driver
>> if the quotas are going to be static anyway.
> 
> Essentially this is what we have done so far, but Sameer is looking for
> a way to make this more programmable/flexible. We can always do that if
> there is no other option indeed. However, seems like a good time to see
> if there is a better way.

My thoughts on resolving this, in order of preference, would be ...

1. Add a new 'fifo_size' variable as Sameer is proposing.
2. Update the ADMA driver to use src/dst_maxburst as the fifo size and
   then have the ADMA driver set a suitable burst size for its burst
   size.
3. Resort to a static configuration.

I can see that #1 only makes sense if others would find it useful,
otherwise #2, may give us enough flexibility for now.

Cheers
Jon

-- 
nvpublic

  reply index

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-30 11:30 Sameer Pujar
2019-04-30 11:30 ` [PATCH] " Sameer Pujar
2019-05-02  6:04 ` Vinod Koul
2019-05-02  6:04   ` [PATCH] " Vinod Koul
2019-05-02 10:53   ` Sameer Pujar
2019-05-02 12:25     ` Vinod Koul
2019-05-02 13:29       ` Sameer Pujar
2019-05-03 19:10         ` Peter Ujfalusi
2019-05-04 10:23         ` Vinod Koul
2019-05-06 13:04           ` Sameer Pujar
2019-05-06 15:50             ` Vinod Koul
2019-06-06  3:49               ` Sameer Pujar
2019-06-06  6:00                 ` Peter Ujfalusi
2019-06-06  6:41                   ` Sameer Pujar
2019-06-06  7:14                     ` Jon Hunter
2019-06-06 10:22                       ` Peter Ujfalusi
2019-06-06 10:49                         ` Jon Hunter
2019-06-06 11:54                           ` Peter Ujfalusi
2019-06-06 12:37                             ` Jon Hunter
2019-06-06 13:45                               ` Dmitry Osipenko
2019-06-06 13:55                                 ` Dmitry Osipenko
2019-06-06 14:26                                   ` Jon Hunter
2019-06-06 14:36                                     ` Jon Hunter [this message]
2019-06-06 14:36                                     ` Dmitry Osipenko
2019-06-06 14:47                                       ` Jon Hunter
2019-06-06 14:25                                 ` Jon Hunter
2019-06-06 15:18                                   ` Dmitry Osipenko
2019-06-06 16:32                                     ` Jon Hunter
2019-06-06 16:44                                       ` Dmitry Osipenko
2019-06-06 16:53                                         ` Jon Hunter
2019-06-06 17:25                                           ` Dmitry Osipenko
2019-06-06 17:56                                             ` Dmitry Osipenko
2019-06-07  9:24                                             ` Jon Hunter
2019-06-07  5:50                               ` Peter Ujfalusi
2019-06-07  9:18                                 ` Jon Hunter
2019-06-07 10:27                                   ` Jon Hunter
2019-06-07 12:17                                     ` Peter Ujfalusi
2019-06-07 12:58                                       ` Jon Hunter
2019-06-07 13:35                                         ` Peter Ujfalusi
2019-06-07 20:53                                           ` Dmitry Osipenko
2019-06-10  8:01                                             ` Jon Hunter
2019-06-10  7:59                                           ` Jon Hunter
2019-06-13  4:43                 ` Vinod Koul
2019-06-17  7:07                   ` Sameer Pujar
2019-06-18  4:33                     ` Vinod Koul
2019-06-20 10:29                       ` Sameer Pujar
2019-06-24  6:26                         ` Vinod Koul
2019-06-25  2:57                           ` Sameer Pujar
2019-07-05  6:15                             ` Sameer Pujar
2019-07-15 15:42                               ` Sameer Pujar
2019-07-19  5:04                               ` Vinod Koul
2019-07-23  5:54                                 ` Sameer Pujar
2019-07-29  6:10                                   ` Vinod Koul
2019-07-31  9:48                                     ` Jon Hunter
2019-07-31 15:16                                       ` Vinod Koul
2019-08-02  8:51                                         ` Jon Hunter
2019-08-08 12:38                                           ` Vinod Koul
2019-08-19 15:56                                             ` Jon Hunter
2019-08-20 11:05                                               ` Vinod Koul
2019-09-16  9:02                                                 ` Sameer Pujar

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