Merge tag 'csky-for-linus-4.20' of https://github.com/c-sky/csky-linux

Pull C-SKY architecture port from Guo Ren:
 "This contains the Linux port for C-SKY(csky) based on linux-4.19
  Release, which has been through 10 rounds of review on mailing list.

  More information:

    http://en.c-sky.com

  The development repo:

    https://github.com/c-sky/csky-linux

  ABI Documentation:

    https://github.com/c-sky/csky-doc

  Here is the pre-built cross compiler for fast test from our CI:

    https://gitlab.com/c-sky/buildroot/-/jobs/101608095/artifacts/file/output/images/csky_toolchain_qemu_csky_ck807f_4.18_glibc_defconfig_482b221e52908be1c9b2ccb444255e1562bb7025.tar.xz

  We use buildroot as our CI-test enviornment. "LTP, Lmbench ..." will
  be tested for every commit. See here for more details:

    https://gitlab.com/c-sky/buildroot/pipelines

  We'll continouslly improve csky subsystem in future"

Arnd acks, and adds the following notes:
 "I did a thorough review of the ABI, which as usual mainly consists of
  spotting any files that don't use the asm-generic ABI itself, and
  having it changed to it matches exactly what we do on other new
  architectures.

  I also looked at every other patch and commented on maybe half of them
  where I saw something that did not quite seem right. Others have
  reviewed specific patches in greater depth. I'm sure that one could
  fine more of the minor details, but as long as they are not ABI
  relevant, they can be fixed later.

  The only patch that is part of the ABI and that nobody reviewed is the
  signal handling. This is one of the areas I never worked on in much
  detail. I did not see anything wrong with it, but I also don't know
  what the problems with the other architectures are here, and we seem
  to be hitting issues occasionally, and we never managed to generalize
  this enough for new architectures to have a trivial implementation.

  I was originally hoping that we could have the 64-bit time_t
  interfaces ready in time to completely drop the 32-bit ones, but that
  did not happen. We might still remove them in the next merge window
  depending on whether the libc upstream people prefer to keep them or
  not.

  One more general comment: I think this may well be the last new CPU
  architecture we ever add to the kernel. Both nds32 and c-sky are made
  by companies that also work on risc-v, and generally speaking risc-v
  seems to be killing off any of the minor licensable instruction set
  projects, just like ARM has mostly killed off the custom
  vendor-specific instruction sets already.

  If we add another architecture in the future, it may instead be
  something like the LLVM bitcode or WebAssembly, who knows?"

To which Geert Uytterhoeven pipes in about another architecture still in
the pipeline: Kalray MPPA.

* tag 'csky-for-linus-4.20' of https://github.com/c-sky/csky-linux: (24 commits)
  dt-bindings: interrupt-controller: C-SKY APB intc
  irqchip: add C-SKY APB bus interrupt controller
  dt-bindings: interrupt-controller: C-SKY SMP intc
  irqchip: add C-SKY SMP interrupt controller
  MAINTAINERS: Add csky
  dt-bindings: Add vendor prefix for csky
  dt-bindings: csky CPU Bindings
  csky: Misc headers
  csky: SMP support
  csky: Debug and Ptrace GDB
  csky: User access
  csky: Library functions
  csky: ELF and module probe
  csky: Atomic operations
  csky: IRQ handling
  csky: VDSO and rt_sigreturn
  csky: Process management and Signal
  csky: MMU and page table management
  csky: Cache and TLB routines
  csky: System Call
  ...

127 files changed, 10562 insertions, 0 deletions

diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
new file mode 100644
index 000000000000..0a0558567eaa
--- /dev/null
+++ b/arch/csky/Kconfig
@@ -0,0 +1,205 @@
+config CSKY
+	def_bool y
+	select ARCH_HAS_SYNC_DMA_FOR_CPU
+	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
+	select ARCH_USE_BUILTIN_BSWAP
+	select ARCH_USE_QUEUED_RWLOCKS if NR_CPUS>2
+	select COMMON_CLK
+	select CLKSRC_MMIO
+	select CLKSRC_OF
+	select DMA_DIRECT_OPS
+	select DMA_NONCOHERENT_OPS
+	select IRQ_DOMAIN
+	select HANDLE_DOMAIN_IRQ
+	select DW_APB_TIMER_OF
+	select GENERIC_LIB_ASHLDI3
+	select GENERIC_LIB_ASHRDI3
+	select GENERIC_LIB_LSHRDI3
+	select GENERIC_LIB_MULDI3
+	select GENERIC_LIB_CMPDI2
+	select GENERIC_LIB_UCMPDI2
+	select GENERIC_ALLOCATOR
+	select GENERIC_ATOMIC64
+	select GENERIC_CLOCKEVENTS
+	select GENERIC_CPU_DEVICES
+	select GENERIC_IRQ_CHIP
+	select GENERIC_IRQ_PROBE
+	select GENERIC_IRQ_SHOW
+	select GENERIC_IRQ_MULTI_HANDLER
+	select GENERIC_SCHED_CLOCK
+	select GENERIC_SMP_IDLE_THREAD
+	select HAVE_ARCH_TRACEHOOK
+	select HAVE_GENERIC_DMA_COHERENT
+	select HAVE_KERNEL_GZIP
+	select HAVE_KERNEL_LZO
+	select HAVE_KERNEL_LZMA
+	select HAVE_C_RECORDMCOUNT
+	select HAVE_DMA_API_DEBUG
+	select HAVE_DMA_CONTIGUOUS
+	select HAVE_MEMBLOCK
+	select MAY_HAVE_SPARSE_IRQ
+	select MODULES_USE_ELF_RELA if MODULES
+	select NO_BOOTMEM
+	select OF
+	select OF_EARLY_FLATTREE
+	select OF_RESERVED_MEM
+	select PERF_USE_VMALLOC
+	select RTC_LIB
+	select TIMER_OF
+	select USB_ARCH_HAS_EHCI
+	select USB_ARCH_HAS_OHCI
+
+config CPU_HAS_CACHEV2
+	bool
+
+config CPU_HAS_FPUV2
+	bool
+
+config CPU_HAS_HILO
+	bool
+
+config CPU_HAS_TLBI
+	bool
+
+conf