• Benjamin Herrenschmidt's avatar
    powerpc/4xx: Add support for ISA holes on 4xx PCI/X/E · 84d727a1
    Benjamin Herrenschmidt authored
    This adds support for ISA memory holes on the PCI, PCI-X and
    PCI-E busses of the 4xx platforms. The patch includes changes
    to the Bamboo and Canyonlands device-trees to add such a hole,
    others can be updated separately.
    
    The ISA memory hole is an additional outbound window configured
    in the bridge to generate PCI cycles in the low memory addresses,
    thus allowing to access things such as the hard-decoded VGA
    aperture at 0xa0000..0xbffff or other similar things. It's made
    accessible to userspace via the new legacy_mem file in sysfs for
    which support was added by a previous patch.
    Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
    Signed-off-by: default avatarJosh Boyer <jwboyer@linux.vnet.ibm.com>
    84d727a1
ppc4xx_pci.c 49 KB