[PATCH rtems-docs 2/2] user/zynqmp: Add NAND driver information

[Chris Johns]

On 22/3/2023 1:18 pm, Kinsey Moore wrote:
> On Tue, Mar 21, 2023 at 7:39 PM Chris Johns <chrisj at rtems.org
> <mailto:chrisj at rtems.org>> wrote:
> 
>     On 22/3/2023 7:00 am, Kinsey Moore wrote:
>     > ---
>     >  user/bsps/aarch64/xilinx-zynqmp.rst | 9 +++++++++
>     >  1 file changed, 9 insertions(+)
>     >
>     > diff --git a/user/bsps/aarch64/xilinx-zynqmp.rst
>     b/user/bsps/aarch64/xilinx-zynqmp.rst
>     > index 4de0115..e30c3f6 100644
>     > --- a/user/bsps/aarch64/xilinx-zynqmp.rst
>     > +++ b/user/bsps/aarch64/xilinx-zynqmp.rst
>     > @@ -250,6 +250,15 @@ Console Driver
>     >  The console driver supports the default Qemu emulated ARM PL011 PrimeCell
>     UART
>     >  as well as the physical ARM PL011 PrimeCell UART in the ZynqMP hardware.
>     > 
>     > +NAND Controller Driver
>     > +----------------------
>     > +
>     > +The ZynqMP BSP has a NAND controller driver which allows writing to and
>     reading
>     > +from one or more attached NAND chips. This driver was imported from the
>     Xilinx
>     > +embeddedsw repository and requires the clock to be configured since it is a
>     > +polling driver and not interrupt-driven. This driver is only available for
>     > +hardware BSPs since QEMU does not emulate the NAND controller.
> 
>     Is the JFFS support that uses this driver for production or just an example?
> 
>     I ask because the QSPI driver takes control of the whole flash and that is
>     confusing if you run an app that has a boot image in the same device because the
>     JFFS erases it.
> 
> 
> The JFFS2 glue in the ZynqMP BSP (both NAND and NOR) is perfectly usable in
> production, but it does not encompass every use case that may exist which is why
> it is not run by default. The user would need to customize their own version of
> the glue code if they have requirements beyond "use the whole device".

Is this worth explaining? It confused us when we played with the code.

Chris