From: Sourav Poddar <sourav.poddar@ti.com>
To: Mark Brown <broonie@kernel.org>
Cc: Peter Korsgaard <peter@korsgaard.com>,
Brian Norris <computersforpeace@gmail.com>,
"Balbi, Felipe" <balbi@ti.com>,
"linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
"Gupta, Pekon" <pekon@ti.com>,
"spi-devel-general@lists.sourceforge.net"
<spi-devel-general@lists.sourceforge.net>,
Trent Piepho <tpiepho@gmail.com>,
David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH 1/3] spi/qspi: Add memory mapped read support.
Date: Fri, 18 Oct 2013 09:36:06 +0530 [thread overview]
Message-ID: <5260B3AE.9070308@ti.com> (raw)
In-Reply-To: <20131017234230.GZ2443@sirena.org.uk>
On Friday 18 October 2013 05:12 AM, Mark Brown wrote:
> On Thu, Oct 17, 2013 at 01:03:26PM +0000, Gupta, Pekon wrote:
>
>> mtd_read() {
>> if (flash->mmap_mode)
>> if (dma_available)
>> read_via_dma(destination, source, length);
>> else
>> memcpy(destination, source, length);
>> else
>> /* use spi frame-work by default */
>> }
>> Are you looking for comparison between read_via_dma() v/s memcpy() ?
> No, I'm looking for a comparison of normal SPI mode (which I'd have
> expected to DMA) and the memcpy() mode.
>
>> If yes, then unfortunately we are bit constrained because our controller
>> does not support DMA. So, we have to depend on CPU based memcpy()
>> only. However, use of DMA can be added as an independent patch on
>> top of this CASE-2 patch.
> However if the controller can't DMA at all then that's not going to be
> possible... am I understanding you correctly that normal SPI can't DMA?
Yes, you are correct, the normal SPI cant DMA.
next prev parent reply other threads:[~2013-10-18 4:07 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-09 15:24 [PATCH 0/3]Add quad/memory mapped support for SPI flash Sourav Poddar
2013-10-09 15:24 ` [PATCH 1/3] spi/qspi: Add memory mapped read support Sourav Poddar
2013-10-09 16:07 ` Mark Brown
2013-10-09 16:54 ` Sourav Poddar
2013-10-09 17:40 ` Mark Brown
2013-10-09 18:15 ` Sourav Poddar
2013-10-09 18:41 ` Mark Brown
2013-10-09 19:01 ` Peter Korsgaard
2013-10-09 19:36 ` Mark Brown
2013-10-10 2:27 ` Trent Piepho
2013-10-10 8:52 ` Sourav Poddar
2013-10-10 10:14 ` Mark Brown
2013-10-10 10:17 ` Sourav Poddar
2013-10-10 11:08 ` Sourav Poddar
2013-10-11 10:08 ` Mark Brown
2013-10-15 6:06 ` Sourav Poddar
2013-10-15 11:16 ` Mark Brown
2013-10-15 11:49 ` Sourav Poddar
2013-10-15 12:46 ` Mark Brown
2013-10-15 13:23 ` Sourav Poddar
2013-10-15 15:33 ` Gupta, Pekon
2013-10-15 16:01 ` Mark Brown
2013-10-15 16:54 ` Gupta, Pekon
2013-10-15 15:53 ` Mark Brown
2013-10-15 18:01 ` Brian Norris
2013-10-15 18:10 ` Sourav Poddar
2013-10-15 18:13 ` Trent Piepho
2013-10-15 18:33 ` Gupta, Pekon
2013-10-15 20:52 ` Mark Brown
2013-10-15 21:03 ` Trent Piepho
2013-10-15 22:10 ` Mark Brown
2013-10-17 12:24 ` Sourav Poddar
2013-10-17 12:38 ` Mark Brown
2013-10-17 13:03 ` Gupta, Pekon
2013-10-17 23:42 ` Mark Brown
2013-10-18 4:06 ` Sourav Poddar [this message]
2013-10-18 5:56 ` Trent Piepho
2013-10-18 6:10 ` Sourav Poddar
2013-10-18 7:27 ` Sourav Poddar
2013-10-18 10:31 ` Mark Brown
2013-10-18 11:48 ` Sourav Poddar
2013-10-18 13:08 ` Mark Brown
2013-10-18 14:47 ` Sourav Poddar
2013-10-15 20:59 ` Mark Brown
2013-10-11 9:30 ` Gupta, Pekon
2013-10-10 10:10 ` Mark Brown
[not found] ` <CA+7tXigijA6ASOiHkRDz45PTruv2vwYJu0UUWz0hvKr0=zwu5w@mail.gmail.com>
2013-10-11 9:59 ` Mark Brown
2013-10-09 15:24 ` [PATCHv3 2/3] drivers: mtd: devices: Add quad " Sourav Poddar
2013-10-09 18:15 ` Jagan Teki
2013-10-11 7:10 ` Gupta, Pekon
2013-10-24 1:06 ` Brian Norris
2013-10-24 5:44 ` Sourav Poddar
2013-10-24 7:34 ` Brian Norris
2013-10-24 8:44 ` Sourav Poddar
2013-10-24 17:07 ` Brian Norris
2013-10-24 17:55 ` Sourav Poddar
2013-10-09 15:24 ` [RFC/PATCH 3/3] drivers: mtd: devices: Add memory mapped " Sourav Poddar
2013-10-09 15:45 ` Mark Brown
2013-10-24 0:22 ` [PATCH 0/3]Add quad/memory mapped support for SPI flash Brian Norris
2013-10-24 4:51 ` Sourav Poddar
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