Treat it as is.
It is a dirty laundry of HW engineers and you may need to communicate with them or read Errata docs on CPU.
If it is about a way how it is written - ask Steven, initially it was in mainland probe code but he think it should be a separate function. I just corrected him, pointing that erratas on 74K and 1074K are different. But because he insist on having the same CPU_74K for both, so...
- Leonid.
PS. If you think the code is bad, please be specific beyond broad blame.
Paul Burton <Paul.Burton@xxxxxxxxxx> wrote:
Could you expand on that please? What is errata E16, what are "some
problems" and how does this fix those problems? The commit message is
somewhat lacking...
Paul
On 11/09/13 21:01, Steven J. Hill wrote:
> From: Leonid Yegoshin <Leonid.Yegoshin@xxxxxxxxxx>
>
> Fixes errata E16 for some problems on 1074K cores.
>
> Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@xxxxxxxxxx>
> Signed-off-by: Steven J. Hill <Steven.Hill@xxxxxxxxxx>
> ---
> arch/mips/mm/c-r4k.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
> index f749f68..8d3ed32 100644
> --- a/arch/mips/mm/c-r4k.c
> +++ b/arch/mips/mm/c-r4k.c
> @@ -786,12 +786,12 @@ static inline void alias_74k_erratum(struct cpuinfo_mips *c)
> * aliases. In this case it is better to treat the cache as always
> * having aliases.
> */
> - if ((c->processor_id & 0xff) <= PRID_REV_ENCODE_332(2, 4, 0))
> - c->dcache.flags |= MIPS_CACHE_VTAG;
> - if ((c->processor_id & 0xff) == PRID_REV_ENCODE_332(2, 4, 0))
> - write_c0_config6(read_c0_config6() | MIPS_CONF6_SYND);
> - if (((c->processor_id & 0xff00) == PRID_IMP_1074K) &&
> - ((c->processor_id & 0xff) <= PRID_REV_ENCODE_332(1, 1, 0))) {
> + if ((c->processor_id & 0xff00) != PRID_IMP_1074K) {
> + if ((c->processor_id & 0xff) <= PRID_REV_ENCODE_332(2, 4, 0))
> + c->dcache.flags |= MIPS_CACHE_VTAG;
> + if ((c->processor_id & 0xff) == PRID_REV_ENCODE_332(2, 4, 0))
> + write_c0_config6(read_c0_config6() | MIPS_CONF6_SYND);
> + } else if ((c->processor_id & 0xff) <= PRID_REV_ENCODE_332(1, 1, 0)) {
> c->dcache.flags |= MIPS_CACHE_VTAG;
> write_c0_config6(read_c0_config6() | MIPS_CONF6_SYND);
> }
