-----Original Message----- From: Jagan Teki jagan@amarulasolutions.com Sent: Tuesday, April 21, 2020 1:45 PM To: Kuldeep Singh kuldeep.singh@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
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On Tue, Apr 21, 2020 at 11:57 AM Kuldeep Singh mailto:kuldeep.singh@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