• Ivan Kokshaysky's avatar
    alpha: fix RTC on marvel · 5f7dc5d7
    Ivan Kokshaysky authored
    Unlike other alphas, marvel doesn't have real PC-style CMOS clock hardware
    - RTC accesses are emulated via PAL calls.  Unfortunately, for unknown
    reason these calls work only on CPU #0.  So current implementation for
    arbitrary CPU makes CMOS_READ/WRITE to be executed on CPU #0 via IPI.
    However, for obvious reason this doesn't work with standard
    get/set_rtc_time() functions, where a bunch of CMOS accesses is done with
    disabled interrupts.
    
    Solved by making the IPI calls for entire get/set_rtc_time() functions,
    not for individual CMOS accesses.  Which is also a lot more effective
    performance-wise.
    
    The patch is largely based on the code from Jay Estabrook.
    My changes:
    - tweak asm-generic/rtc.h by adding a couple of #defines to
      avoid a massive code duplication in arch/alpha/include/asm/rtc.h;
    - sys_marvel.c: fix get/set_rtc_time() return values (Jay's FIXMEs).
    
    NOTE: this fixes *only* LIB_RTC drivers.  Legacy (CONFIG_RTC) driver
    wont't work on marvel.  Actually I think that we should just disable
    CONFIG_RTC on alpha (maybe in 2.6.30?), like most other arches - AFAIK,
    all modern distributions use LIB_RTC anyway.
    Signed-off-by: default avatarIvan Kokshaysky <ink@jurassic.park.msu.ru>
    Cc: Richard Henderson <rth@twiddle.net>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    5f7dc5d7
machvec.h 3.53 KB