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    sh: add support for J-Core J2 processor · 5a846aba
    Rich Felker authored
    
    
    At the CPU/ISA level, the J2 is compatible with SH-2, and thus the
    changes to add J2 support build on existing SH-2 support. However, J2
    does not duplicate the memory-mapped SH-2 features like the cache
    interface. Instead, the cache interfaces is described in the device
    tree, and new code is added to be able to access the flat device tree
    at early boot before it is unflattened.
    
    Support is also added for receiving interrupts on trap numbers in the
    range 16 to 31, since the J-Core aic1 interrupt controller generates
    these traps. This range was unused but nominally for hardware
    exceptions on SH-2, and a few values in this range were used for
    exceptions on SH-2A, but SH-2A has its own version of the relevant
    code.
    
    No individual cpu subtypes are added for J2 since the intent moving
    forward is to represent SoCs with device tree rather than as
    hard-coded subtypes in the kernel. The CPU_SUBTYPE_J2 Kconfig item
    exists only to fit into the existing cpu selection mechanism until it
    is overhauled.
    
    Signed-off-by: default avatarRich Felker <dalias@libc.org>
    5a846aba