Groups > linux.kernel > #1200426

Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read

From	Michal Suchanek <hramrach@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read
Date	2015-08-05 08:00 +0200
Message-ID	<pTZU6-GE-3@gated-at.bofh.it> (permalink)
References	(3 earlier) <pTg0V-PQ-1@gated-at.bofh.it> <pTMNc-6DQ-3@gated-at.bofh.it> <pTOP0-1jD-9@gated-at.bofh.it> <pTZr4-89-13@gated-at.bofh.it> <pTZAK-jr-13@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 5 August 2015 at 07:35, Vignesh R <vigneshr@ti.com> wrote:
>
>
> On 08/05/2015 10:51 AM, Michal Suchanek wrote:
>> Hello,
>>
>> On 4 August 2015 at 19:59, R, Vignesh <vigneshr@ti.com> wrote:
>>>
>>>
>>> On 8/4/2015 9:21 PM, Mark Brown wrote:
>>>> On Mon, Aug 03, 2015 at 10:27:19AM +0530, Vignesh R wrote:
>>>>

>>>
>>> TI QSPI controller has two blocks:
>>> 1. SPI_CORE: This is generic(normal) spi mode. This can be used to
>>> communicate with any SPI devices (serial flashes as well as non-flash
>>> devices like touchscreen).
>>> 2. SFI_MM_IF(SPI memory mapped interface): The SFI_MM_IF block only
>>> allows reading and writing to an SPI flash device only. Used to speed up
>>> flash reads. It _cannot_ be used to communicate with non flash devices.
>>> Now, the spi_message that ti-qspi receives in transfer_one() callback
>>> can be from mtd device(in which case SFI_MM_IF can be used) or from any
>>> other non flash SPI device (in which case SFI_MM_IF must not be used
>>> instead SPI_CORE is to be used) but there is no way(is there?) to
>>> distinguish where spi_message is from. Therefore I introduced flag
>>> (use_mmap_mode) to struct spi_message. mtd driver will set flag to true,
>>> this helps the ti-qspi driver to determine that the user is flash device
>>> and thus can do read via SFI_MM_IF. If this flag is not set then the
>>> user is assumed to be non flash SPI driver and will use SPI_CORE block
>>> to communicate.
>>>
>>> On the whole, I just need a way to determine that the user is a flash
>>> device in order to switch to memory mapped interface.
>>>
>>
>> Maybe it can be set on the SPI slave rather than each message.
>
> You mean to add flag to spi_device struct? That's ok for me.
>

There are already mode flags so you can just add one more.

Thanks

Michal
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Thread

[RFC PATCH 0/5] Add memory mapped read support for TI QSPI. Vignesh R <vigneshr@ti.com> - 2015-07-28 10:50 +0200
  [RFC PATCH 4/5] ARM: dts: DRA7: Add memory map region entries for qspi Vignesh R <vigneshr@ti.com> - 2015-07-28 10:50 +0200
    Re: [RFC PATCH 4/5] ARM: dts: DRA7: Add memory map region entries  for qspi Vignesh R <vigneshr@ti.com> - 2015-08-03 07:10 +0200
      Re: [RFC PATCH 4/5] ARM: dts: DRA7: Add memory map region entries  for qspi Mark Brown <broonie@kernel.org> - 2015-08-04 18:00 +0200
    Re: [RFC PATCH 4/5] ARM: dts: DRA7: Add memory map region entries  for qspi Vignesh R <vigneshr@ti.com> - 2015-08-03 07:10 +0200
    Re: [RFC PATCH 4/5] ARM: dts: DRA7: Add memory map region entries  for qspi Vignesh R <vigneshr@ti.com> - 2015-08-03 07:20 +0200
  [RFC PATCH 2/5] spi: spi-ti-qspi: Add memory mapped read support Vignesh R <vigneshr@ti.com> - 2015-07-28 10:50 +0200
  [RFC PATCH 1/5] spi: introduce flag for memory mapped read Vignesh R <vigneshr@ti.com> - 2015-07-28 10:50 +0200
    Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Vignesh R <vigneshr@ti.com> - 2015-08-03 07:00 +0200
      Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Mark Brown <broonie@kernel.org> - 2015-08-04 18:00 +0200
        Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read "R, Vignesh" <vigneshr@ti.com> - 2015-08-04 20:10 +0200
          Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Michal Suchanek <hramrach@gmail.com> - 2015-08-05 07:30 +0200
            Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Vignesh R <vigneshr@ti.com> - 2015-08-05 07:40 +0200
              Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Michal Suchanek <hramrach@gmail.com> - 2015-08-05 08:00 +0200
          Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Mark Brown <broonie@kernel.org> - 2015-08-05 14:00 +0200
            Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Michal Suchanek <hramrach@gmail.com> - 2015-08-05 14:50 +0200
              Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Mark Brown <broonie@kernel.org> - 2015-08-05 14:50 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Michal Suchanek <hramrach@gmail.com> - 2015-08-05 15:00 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Mark Brown <broonie@kernel.org> - 2015-08-06 11:10 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Michal Suchanek <hramrach@gmail.com> - 2015-08-06 12:10 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-08-06 12:30 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Mark Brown <broonie@kernel.org> - 2015-08-06 13:10 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Michal Suchanek <hramrach@gmail.com> - 2015-08-06 13:10 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Vignesh R <vigneshr@ti.com> - 2015-08-06 14:30 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-08-06 16:00 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Geert Uytterhoeven <geert@linux-m68k.org> - 2015-08-06 18:20 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Michal Suchanek <hramrach@gmail.com> - 2015-08-06 20:30 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-08-06 23:40 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Michal Suchanek <hramrach@gmail.com> - 2015-08-07 09:40 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Vignesh R <vigneshr@ti.com> - 2015-08-07 10:40 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Martin Sperl <martin@sperl.org> - 2015-08-07 10:30 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Michal Suchanek <hramrach@gmail.com> - 2015-08-07 12:20 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Vignesh R <vigneshr@ti.com> - 2015-08-12 11:30 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Mark Brown <broonie@kernel.org> - 2015-08-06 18:50 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Mark Brown <broonie@kernel.org> - 2015-08-06 20:30 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Mark Brown <broonie@kernel.org> - 2015-08-06 13:30 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Michal Suchanek <hramrach@gmail.com> - 2015-08-06 13:50 +0200
                Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read Mark Brown <broonie@kernel.org> - 2015-08-06 18:10 +0200
  [RFC PATCH 5/5] ARM: dts: AM4372: Add memory map region entries for qspi Vignesh R <vigneshr@ti.com> - 2015-07-28 10:50 +0200
  [RFC PATCH 3/5] mtd: devices: m25p80: set flag to request memory mapped read Vignesh R <vigneshr@ti.com> - 2015-07-28 10:50 +0200

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