On Tue, Mar 01, 2016 at 09:39:18AM +0100, Ard Biesheuvel wrote:
> >> As far as the Primecell ID is concerned, let's just whitelist whatever
> >> TC2 exposes, even if in error.
> >
> > You mean rather than mask the "stuck bit", specifically check if the
> > register is 0 or 2? (Where 2 is added as a #define to the header).
>
> I don't care deeply either way, but supporting the documented and the
> actual ID explicitly seems more correct, unless the difference is in
> the revision field?
So ... PeriphID3 holds the "Configuration" bits, so in any case, they
would be irrelevant for identification.
We really should macroise this up a bit better, like Linux does:
/* Some drivers don't use the struct amba_device */
#define AMBA_CONFIG_BITS(a) (((a) >> 24) & 0xff)
#define AMBA_REV_BITS(a) (((a) >> 20) & 0x0f)
#define AMBA_MANF_BITS(a) (((a) >> 12) & 0xff)
#define AMBA_PART_BITS(a) ((a) & 0xfff)
#define amba_config(d) AMBA_CONFIG_BITS((d)->periphid)
#define amba_rev(d) AMBA_REV_BITS((d)->periphid)
#define amba_manf(d) AMBA_MANF_BITS((d)->periphid)
#define amba_part(d) AMBA_PART_BITS((d)->periphid)
(after proper extraction of the 32-bit value from the 4 registers of
course)
Amusingly, the Linux driver ignores pretty much everything, and
accepts any primecell with ARM as designer.
Opens up for cute devicetree hacks, I guess...
/
Leif
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