[PATCH] [RFC] drm: mxsfb: Implement LCDIF scanout CRC32 support

[Liu Ying]

On Tue, 2022-02-08 at 11:02 +0100, Marek Vasut wrote:
> On 2/8/22 03:41, Liu Ying wrote:
> 
> Hello everyone,
> 
> > > > > There are many blank areas which are undocumented, this LCDIF
> > > > > CRC32
> > > > > feature, i.MX8M Mini Arteris NOC at 0x32700000 , the ARM GPV
> > > > > NIC-
> > > > > 301
> > > > > at
> > > > > 0x32{0,1,2,3,4,5,6,8}00000 and their master/slave port
> > > > > mapping.
> > > > > The
> > > > > NOC
> > > > > and NICs were documented at least up to i.MX6QP and then that
> > > > > information disappeared from NXP datasheets. I think
> > > > > reconfiguring
> > > > > the
> > > > > NOC/NIC QoS would help mitigate this shift issue described
> > > > > below
> > > > > (*).
> > > > 
> > > > I also think the QoS would help if it is configureable.
> > > 
> > > It is programmable, it's just the port mapping which is
> > > undocumented.
> > > 
> > > > > Do you know if there is some additional NOC/NIC documentation
> > > > > for
> > > > > i.MX8M
> > > > > Mini available ?
> > > > 
> > > > No.
> > > 
> > > Can you ask someone internally in NXP maybe ?
> > 
> > Maybe, you may try community.nxp.com, like the i.MXRT case.
> 
> The community.nxp.com is unhelpful, the i.MXRT case it a good example
> -- 
> the solution to the problem has been found by the person who asked
> the 
> question on their own, and elsewhere too.

AFAIK, there are questions answered by internal support team and RnD
team at that community.  I personally take it as a resource to use. 

> 
> But note that the i.MXRT interconnect documentation is available in
> the 
> i.MXRT datasheet, which made that possible in the first place. On
> i.MX, 
> all that information has been removed from the datasheet in i.MX7
> and 
> i.MX8M, so I cannot even help myself, even if I wanted to. This is
> very bad.

I'm not familiar with the documention in that area, so I personally
will not be helpful at the documention topic.  The main purpose I
jumped in this thread is to review the patch and share the idea to use
the existing drm debugfs crc support instead of creating a sysfs
attribute.

Liu Ying