> -----Original Message----- > From: Jagan Teki <ja...@amarulasolutions.com> > Sent: Tuesday, April 21, 2020 1:45 PM > To: Kuldeep Singh <kuldeep.si...@nxp.com> > Cc: U-Boot-Denx <u-boot@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.si...@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. Thanks Kuldeep [1] https://elixir.bootlin.com/linux/latest/source/drivers/spi/spi-nxp-fspi.c