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

[Prabhakar Kushwaha]

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?

--pk