Messages in this thread | | | Date | Tue, 29 Mar 2011 12:39:09 -0300 | From | Mauro Carvalho Chehab <> | Subject | Re: [PATCH 05/30] amd64_edac: Cleanup chipselect handling |
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Em 29-03-2011 12:16, Borislav Petkov escreveu: > On Tue, Mar 29, 2011 at 10:56:26AM -0400, Mauro Carvalho Chehab wrote: >> Em 10-02-2011 15:15, Borislav Petkov escreveu: >>> From: Borislav Petkov <borislav.petkov@amd.com> >>> >>> Add a struct representing the DRAM chip select base/limit register >>> pairs. Concentrate all CS handling in a single function. Also, add CS >>> looping macros for cleaner, more readable code. While at it, adjust code >>> to F15h. Finally, do smaller macro names cleanups (remove family names >>> from register macros) and debug messages clarification. >>> >>> No functional change. >>> >>> Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> >> >> Hi Borislav, >> >>> --- a/drivers/edac/amd64_edac.h >>> +++ b/drivers/edac/amd64_edac.h >>> @@ -160,6 +160,14 @@ >>> #define OFF false >>> >>> /* >>> + * Create a contiguous bitmask starting at bit position @lo and ending at >>> + * position @hi. For example >>> + * >>> + * GENMASK(21, 39) gives us the 64bit vector 0x000000ffffe00000. >>> + */ >>> +#define GENMASK(lo, hi) (((1ULL << ((hi) - (lo) + 1)) - 1) << (lo)) >>> + >> >> This is a nice macro that could be useful outside amd64. It is probably a good >> idea to move it to include/linux/bitops.h. > > I'd suggest rather <drivers/edac/edac_core.h> if you want to use it in > EDAC. But if we have more users, I don't have a problem with putting > it there (or somewhere else generic enough if people have a better > suggestion).
Yeah, other edac drivers could benefit of using it, and also could benefit on a variant that would do an AND operation and shift it, something like (untested):
/* * Create a contiguous bitmask starting at bit position @lo and ending at * position @hi. For example * * APPLY_BITMASK(v, 21, 39) will return the result of: * (v & 0x000000ffffe00000) >> 21 */ #define APPLY_BITMASK(v, lo, hi) (((v) & ((1ULL << ((hi) - (lo) + 1)) - 1) << (lo)) >> (lo))
Almost all edac drivers do something like the above, for example, to get DIMM rows/cols/banks, etc.
Probably, the most complex part is to find a nice name for it ;)
Yet, I think non-edac drivers could also benefit of such macro, and, as this is not edac-specific, I think it would be better to add it at bitops.h.
Cheers, Mauro
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