[U-Boot] [RFC 0/5] sf: Update spi-nor framework

[Jagan Teki]

On Tue, Dec 12, 2017 at 11:44 AM, Prabhakar Kushwaha
<prabhakar.kushwaha at nxp.com> wrote:
> Hi Marek,
>
>> -----Original Message-----
>> From: Marek Vasut [mailto:marek.vasut at gmail.com]
>> Sent: Monday, December 11, 2017 3:04 PM
>> To: Prabhakar Kushwaha <prabhakar.kushwaha at nxp.com>; u-
>> boot at lists.denx.de
>> Cc: jagannadh.teki at gmail.com; Poonam Aggrwal
>> <poonam.aggrwal at nxp.com>; Suresh Gupta <suresh.gupta at nxp.com>;
>> cyrille.pitchen at atmel.com
>> Subject: Re: [RFC 0/5] sf: Update spi-nor framework
>>
>> On 12/11/2017 06:57 AM, Prabhakar Kushwaha wrote:
>> > SPI-NOR framework currently supports-
>> >  - (1-1-1, 1-1-2, 1-1-4) read protocols
>> >  - read latency(dummy bytes) are hardcoded with the assumption
>> >  that the flash would support it.
>> >  - No support of mode bits.
>> >  - No support of flash size above 128Mib
>> >
>> > This patch set add support of 1-2-2, 1-4-4 read protocols.
>> > It ports Linux commits "mtd: spi-nor: add a stateless method to support
>> > memory size above 128Mib" and "mtd: spi-nor: parse Serial Flash
>> > Discoverable Parameters (SFDP) tables". It enables 4byte address opcode
>> > and run time flash parameters discovery including dummy cycle and mode
>> > cycle.
>> >
>> > Finally it update fsl-quadspi driver to store(set_mode) spi bus mode and
>> > provision for run-time LUTs creation.
>> >
>> > Note: This patch-set is only **compliation** tested. Sending RFC to get
>> > early feed-back on the approach.
>> >
>> > Prabhakar Kushwaha (5):
>> >   sf: Add support of 1-2-2, 1-4-4 IO READ protocols
>> >   sf: add method to support memory size above 128Mib
>> >   sf: parse Serial Flash Discoverable Parameters (SFDP) tables
>> >   sf: fsl_qspi: Add support of fsl_qspi_set_mode
>> >   sf: fsl_quadspi: Configue LUT based on padding information
>> >
>> >  drivers/mtd/spi/sf_internal.h   | 230 +++++++++++++++-
>> >  drivers/mtd/spi/spi_flash.c     | 574
>> +++++++++++++++++++++++++++++++++++++++-
>> >  drivers/spi/fsl_qspi.c          |  85 +++++-
>> >  include/spi_flash.h             |   2 +
>> >  5 files changed, 875 insertions(+), 18 deletions(-)
>> >
>>
>> Could you rather port the entire SPI NOR framework from Linux 4.14 ?
>> That'd make more sense than porting bits and pieces on top of the
>> current crappy code IMO.
>
> I agree with you. Linux 4.14 SPI NOR framework should be ported.
> I may not able to do this because of bandwidth and lack of expertise.
> I will request Jagan (custodian) to look into this.
>
> This RFC patch-set can easily be applied to existing and  ported Linux SPI NOR framework when it gets available.
>
> For now, I think these patches(the next version) with the existing framework can be reviewed and accepted.
> Please help to share your views.
>
> For next version of this patch set, I will be working on testing  it to enable other flashes.
> It will also help Jagan during 4.14 porting.
> Jagan, your views?

direct-porting from Linux is not so optimal(not well suited for U-Boot
design) as I've tried before. We're working on the dm-driven spi-nor.
So I will continue to review your patches on current code and will see
how we can merge the same once dm-spi-nor available.

Jagan.