[U-Boot] [PATCH] powerpc/85xx: Add workaround for errata USB-14 (enable on P204x/P3041/P50x0)

[Kumar Gala]

On Mar 5, 2013, at 2:40 PM, Wolfgang Denk wrote:

> Dear Xu Lei-B33228,
> 
> Please do not top post / full quote.  Thanks.
> 
> In message <8CB6A38ADF9E994697FF8A45E96E085338810E at 039-SN1MPN1-004.039d.mgd.msft.net> you wrote:
>> 
>> 	Thank you and I agree with you. It is a little ugly but because these registers info are not publicly, so I did not use C struct to describe them, 
>> for this case is it ok, or other method such as define a struct but keep all other registers and bits in this register reserved? Thank you.
> 
> I'm not throwing in a formal NAK here, but for reasons of consistency
> (and because others are just too eager to quote such patches as
> authoritative precedent) I'd prefer the use of a struct.

While I'd prefer a struct as well, unfortunately this isn't something FSL has documented and we publish the erratum write ups with address like this.  So when a customer comes and looks for the code its more inline with the erratum writeup.

I'm not sure what value a dummy struct would provide above the explicit addressing utilized in the patch.

Again, I'm not happy about the situation, just not sure what additional value doing something like:

struct dummy_usb_dscr {
	u8 res[0x520];
	u32 erratum_usb14_reg;
	u8 res[4096-0x524];
};

Its going to be a bit more error prone than the method used when the struct needs updating for a new register field and when someone screws up getting the res[] sizes correct.

- k