On Tuesday 04 October 2011 12:43:44 Mark Salter wrote: > 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: Mark Salter <msalter@xxxxxxxxxx> > Signed-off-by: Aurelien Jacquiot <a-jacquiot@xxxxxx> > CC: devicetree-discuss@xxxxxxxxxxxxxxxx > CC: Grant Likely <grant.likely@xxxxxxxxxxxx> > CC: Arnd Bergmann <arnd@xxxxxxxx> Acked-by: Arnd Bergmann <arnd@xxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
