• Arnd Bergmann's avatar
    [PATCH] spufs: implement mfc access for PPE-side DMA · a33a7d73
    Arnd Bergmann authored
    This patch adds a new file called 'mfc' to each spufs directory.
    The file accepts DMA commands that are a subset of what would
    be legal DMA commands for problem state register access. Upon
    reading the file, a bitmask is returned with the completed
    tag groups set.
    
    The file is meant to be used from an abstraction in libspe
    that is added by a different patch.
    
    From the kernel perspective, this means a process can now
    offload a memory copy from or into an SPE local store
    without having to run code on the SPE itself.
    
    The transfer will only be performed while the SPE is owned
    by one thread that is waiting in the spu_run system call
    and the data will be transferred into that thread's
    address space, independent of which thread started the
    transfer.
    Signed-off-by: default avatarArnd Bergmann <arnd.bergmann@de.ibm.com>
    Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    a33a7d73
backing_ops.c 9.17 KB