topic Re: Using QuadSPI to access SRAM Memory in i.MX Processors

Using QuadSPI to access SRAM Memory

frk — Tue, 15 Dec 2020 12:47:18 GMT

Hi everyone,

I'm actually trying to use the QuadSpi bus to access to a SRAM memory with an i.MX8m (kernel 5.4.70) but I don't know where to begin with as I didn't find any drivers for the memory in the kernel sources.

The memory I want to use is a 65WVS5128GALL from ISSI.

How can I map the SRAM to QuadSpi and see the mtd device in the userspace? Using device tree I assume but without specific driver for the memory?

Re: Using QuadSPI to access SRAM Memory

igorpadykov — Wed, 16 Dec 2020 00:51:37 GMT

Hi frk

unfortunately such devices are not supported in nxp bsps and new driver with

specific LUT (Look-up Table) for that device should be developed.

One can start with sect.3.8 SPI NOR Flash Memory Technology Device (MTD)

i.MX Linux Reference Manual

Look-up Table description can be found in sect.10.2.4.3.4 Look-up Table,

sect.10.2.7.1.3 Fast Read Quad Output (Winbond)

i.MX 8M Dual/8M QuadLite/8M Quad Applications Processors Reference Manual

Best regards
igor

Re: Using QuadSPI to access SRAM Memory

frk — Tue, 22 Dec 2020 15:06:41 GMT

Hi Igor,

Thanks for these hints.

I've seen the following ressource : https://elixir.bootlin.com/linux/latest/source/drivers/mtd/devices/mchp23k256.c

I'm wondering if it could be a good start too.