[EXT] Re: [Patch v2] spi: nxp-fspi: Add 1us delay to make controller ready for next transaction

[Jagan Teki]

On Tue, Apr 21, 2020 at 2:56 PM Kuldeep Singh <kuldeep.singh at nxp.com> wrote:
>
>
>
> > -----Original Message-----
> > From: Jagan Teki <jagan at amarulasolutions.com>
> > Sent: Tuesday, April 21, 2020 1:45 PM
> > To: Kuldeep Singh <kuldeep.singh at nxp.com>
> > Cc: U-Boot-Denx <u-boot at lists.denx.de>
> > Subject: [EXT] Re: [Patch v2] spi: nxp-fspi: Add 1us delay to make controller
> > ready for next transaction
> >
> > Caution: EXT Email
> >
> > On Tue, Apr 21, 2020 at 11:57 AM Kuldeep Singh <mailto:kuldeep.singh at nxp.com>
> > wrote:
> > >
> > > Board gets reset when performing burst read/write operations. On the
> > > other hand, no such behaviour is observed on small size operations.
> > >
> > > In Linux, readl_poll_timeout API already add delay of 1us which is
> > > skipped in U-boot. Since, NXP Flexspi U-boot driver is a ported
> > > version of Linux driver and U-boot poll_timeout API lacks delay
> > > functionality, add 1us delay so as to make controller ready for other
> > transactions.
> >
> > Can you link me, where  does Linux add this delay?
>
> Please see[1] for Linux nxp flexspi driver code.
> fspi_readl_poll_tout, line: 795
>
> If you see implementation of " fspi_readl_poll_tout ", it further calls "readl_poll_timeout" which includes delay of 1us.
> And also please see the difference of "readl_poll_timeout" api implementation in uboot and Linux.
> This api adds delay in Linux but skips it in uboot.

Yes, it worked for myself also. so please use the new api which I have
introduced on this series [2]

[2] https://patchwork.ozlabs.org/project/uboot/patch/20200425110354.12381-3-jagan@amarulasolutions.com/