cvs commit: src/sys/conf files.i386 src/sys/i386/isa elcr.c src/sys/i386/include intr_machdep.h

[John Baldwin]

jhb         2004/05/04 13:07:46 PDT

  FreeBSD src repository

  Modified files:
    sys/conf             files.i386 
    sys/i386/include     intr_machdep.h 
  Added files:
    sys/i386/isa         elcr.c 
  Log:
  Add a simple mini-driver for the ELCR register.  Originally, the ELCR
  register controlled the trigger mode and polarity of EISA interrupts.
  However, it appears that most (all?) PCI systems use the ELCR to manage
  the trigger mode and polarity of ISA interrupts as well since ISA IRQs used
  to route PCI interrupts need to be level triggered with active low
  polarity.  We check to see if the ELCR exists by sanity checking the value
  we get back ensuring that IRQS 0 (8254), 1 (atkbd), 2 (the link from the
  slave PIC), and 8 (RTC) are all clear indicating edge trigger and active
  high polarity.
  
  This mini-driver will be used by the atpic driver to manage the trigger and
  polarity of ISA IRQs.  Also, the mptable parsing code will use this mini
  driver rather than examining the ELCR directly.
  
  Revision  Changes    Path
  1.487     +1 -0      src/sys/conf/files.i386
  1.3       +5 -0      src/sys/i386/include/intr_machdep.h
  1.1       +143 -0    src/sys/i386/isa/elcr.c (new)