Re: [PATCH 0/2] usb: dwc3: Add cache type configuration support for freescale layerscape

[Frank Li]

On Wed, Jul 03, 2024 at 11:33:23PM +0000, Thinh Nguyen wrote:
> Hi Frank,
> 
> On Wed, Jul 03, 2024, Frank Li wrote:
> > There are several attempt to upstream this code in past year.
> > 
> > The first attempt:
> > https://urldefense.com/v3/__https://lore.kernel.org/linux-usb/20191121095356.GB7503@b29397-desktop/__;!!A4F2R9G_pg!cdNydVZ64br9EHG13lgP3lKWe5VuXQvvfvA1CzKJqhXZZB1H9vcJlwI1vj1EF3ynRFl2u8tD3lYqRvrJFSs2$ 
> > 
> > cache type is dwc core setting, not glue layer. So It'd better change in
> > dwc core instead of glue layer code.
> 
> Why not glue layer?

I understand glue layer is what provide clock, reset, power and other
control for dwc usb core and have a seperate mmio register space. All dwc
core register access should belong to dwc-core part. You may have
difference defination for glue layer.

> 
> > 
> > The second attempt:
> > https://urldefense.com/v3/__https://lore.kernel.org/linux-usb/20240123170206.3702413-1-Frank.Li@xxxxxxx/*t__;Iw!!A4F2R9G_pg!cdNydVZ64br9EHG13lgP3lKWe5VuXQvvfvA1CzKJqhXZZB1H9vcJlwI1vj1EF3ynRFl2u8tD3lYqRh7SiHmM$ 
> > 
> > DT team think there are not variable for property 'snps,dat-wr-reqinfo'.
> > And suggest use vendor compatible string.
> > 
> > This is third attempt:
> > Compared with first attempt:
> > - reduce compatible string to one 'fsl,ls-dwc3' because all setting are the
> > same.
> > - move update burst type code into dwc3_set_incr_burst_type(). and check
> > compatible string 'fsl,ls-dwc3'.
> > - Using bit field help macro.
> > 
> > Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
> > ---
> > Ran Wang (2):
> >       dt-bindings: usb: Add chip-specific compatible string 'fsl,ls-dwc3'
> >       usb: dwc3: Set cache type to 'snoop' for freescale layerscape chip
> > 
> >  Documentation/devicetree/bindings/usb/snps,dwc3.yaml |  1 +
> >  drivers/usb/dwc3/core.c                              | 12 ++++++++++++
> >  drivers/usb/dwc3/core.h                              |  4 ++++
> >  3 files changed, 17 insertions(+)
> > ---
> > base-commit: 0b58e108042b0ed28a71cd7edf5175999955b233
> > change-id: 20240703-dwc-5be3e378ddbe
> > 
> > Best regards,
> > ---
> > Frank Li <Frank.Li@xxxxxxx>
> > 
> 
> This may blow up the dwc3 core from various platforms and compatible
> strings. This can be handled in the glue driver and create the software
> property instead.
> 
> Radhey Shyam is working on this also. You can check his work here:
> 
> https://lore.kernel.org/linux-usb/1717657279-2631757-1-git-send-email-radhey.shyam.pandey@xxxxxxx/

This is quite good.

Frank

> 
> Thanks,
> Thinh