1. 01 Feb, 2008 29 commits
  2. 31 Jan, 2008 10 commits
  3. 30 Jan, 2008 1 commit
    • Michael Ellerman's avatar
      [POWERPC] Cell IOMMU fixed mapping support · 99e13912
      Michael Ellerman authored
      
      
      This patch adds support for setting up a fixed IOMMU mapping on certain
      cell machines.  For 64-bit devices this avoids the performance overhead of
      mapping and unmapping pages at runtime.  32-bit devices are unable to use
      the fixed mapping.
      
      The fixed mapping is established at boot, and maps all of physical memory
      1:1 into device space at some offset.  On machines with < 30 GB of memory
      we setup the fixed mapping immediately above the normal IOMMU window.
      
      For example a machine with 4GB of memory would end up with the normal
      IOMMU window from 0-2GB and the fixed mapping window from 2GB to 6GB. In
      this case a 64-bit device wishing to DMA to 1GB would be told to DMA to
      3GB, plus any offset required by firmware.  The firmware offset is encoded
      in the "dma-ranges" property.
      
      On machines with 30GB or more of memory, we are unable to place the fixed
      mapping above the normal IOMMU window as we would run out of address space.
      Instead we move the normal IOMMU window to coincide with the hash page
      table, this region does not need to be part of the fixed mapping as no
      device should ever be DMA'ing to it.  We then setup the fixed mapping
      from 0 to 32GB.
      Signed-off-by: default avatarMichael Ellerman <michael@ellerman.id.au>
      Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
      99e13912