• Mark Salter's avatar
    C6X: devicetree support · 041cadca
    Mark Salter authored
    This is the basic devicetree support for C6X. Currently, four boards are
    supported. Each one uses a different SoC part. Two of the four supported
    SoCs are multicore. One with 3 cores and the other with 6 cores. There is
    no coherency between the core-level caches, so SMP is not an option. It is
    possible to run separate kernel instances on the various cores. There is
    currently no C6X bootloader support for device trees so we build in the DTB
    for now.
    
    There are some interesting twists to the hardware which are of note for device
    tree support. Each core has its own interrupt controller which is controlled
    by special purpose core registers. This core controller provides 12 general
    purpose prioritized interrupt sources. Each core is contained within a
    hardware "module" which provides L1 and L2 caches, power control, and another
    interrupt controller which cascades into the core interrupt controller. These
    core module functions are controlled by memory mapped registers. The addresses
    for these registers are the same for each core. That is, when coreN accesses
    a module-level MMIO register at a given address, it accesses the register for
    coreN even though other cores would use the same address to access the register
    in the module containing those cores. Other hardware modules (timers, enet, etc)
    which are memory mapped can be accessed by all cores.
    
    The timers need some further explanation for multicore SoCs. Even though all
    timer control registers are visible to all cores, interrupt routing or other
    considerations may make a given timer more suitable for use by a core than
    some other timer. Because of this and the desire to have the same image run
    on more than one core, the timer nodes have a "ti,core-mask" property which
    is used by the driver to scan for a suitable timer to use.
    Signed-off-by: default avatarMark Salter <msalter@redhat.com>
    Signed-off-by: default avatarAurelien Jacquiot <a-jacquiot@ti.com>
    Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
    041cadca
emifa.txt 1.63 KB