Workarounds in generic EHCI code

Rafal Jaworowski raj at
Fri Mar 7 15:34:05 UTC 2008

M. Warner Losh wrote:

> : I'd like to hear comments on the proper way of handling non-standard behaviour
> : of a host controller when a workaround needs to be aplied at the shared code
> : level. In the following I followed an example of existing VIA/ATI chip workaround:
> : 
> :
> : 
> : The respective flags are potentially set in platform-specific attachment
> : driver code, which knows if they apply etc.
> : 
> : Does anybody see a better way to handle such cases?
> This seems fine, but...
> +#define EHCI_SCFLG_USBMODEBUG	0x0003	/* workaround for Marvell 88F5281 chipsets */
> +#define EHCI_SCFLG_FORCESPEED	0x0004	/* workaround for Marvell chipsets */
> +#define EHCI_SCFLG_NORESTERM	0x0005	/* don't terminate reset sequence on Marvell chipsets */
> Two comments.  '3' isn't a bit, so those values need to change.

Ah, sure, thanks.

> Second, I'd make the descriptions a little better.  The first two
> aren't very helpful...

I have more detailed descriptions in the platform code that sets this, e.g.

  * Workaround for Marvell 88F5281 integrated EHCI controller: reset of
  * the EHCI core clears the USBMODE register, which sets the core in
  * an undefined state (neither host nor agent), so it needs to be set
  * again for proper operation.
  * Refer to errata document (p. 5.24 GL USB-2) for details.


But maybe it really better fits in the ehic.c/ehcivar.h.. I'll try to improve


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