# RE: \[EXT\] Re: \[PATCH RFC net-next 03/19\] net: mvpp2: add CM3 SRAM memory map

- From: Stefan Chulski \<hidden\>
- Date: 2021-01-10 17:53:01 
- List: netdev
- Page: https://ratatoskr.run/netdev/2021/01/6228953
- Thread: https://ratatoskr.run/netdev/2021/01/6228879/t.md

```text
> 
> > > Should there be -EPROBE_DEFER handling in here somewhere? The SRAM
> > > is a device, so it might not of been probed yet?
> >
> 
> > No, firmware probed during bootloader boot and we can use SRAM. SRAM
> > memory can be safely used.
> 
> A previous patch added:
> 
> +               CP11X_LABEL(cm3_sram): cm3@220000 {
> +                       compatible = "mmio-sram";
> +                       reg = <0x220000 0x800>;
> +                       #address-cells = <1>;
> +                       #size-cells = <1>;
> +                       ranges = <0 0x220000 0x800>;
> +               };
> +
> 
> So it looks like the SRAM is a device, in the linux driver model. And there is a
> driver for this, driver/misc/sram.c. How do you know this device has been
> probed before the Ethernet driver?
> 
>        Andrew

You right, I would add EPROBE_DEFER if of_gen_pool_get return NULL.

Thanks.
```