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
  ...

Documentation/devicetree/bindings/csky/cpus.txt

@@ -0,0 +1,73 @@
+==================
+C-SKY CPU Bindings
+==================
+
+The device tree allows to describe the layout of CPUs in a system through
+the "cpus" node, which in turn contains a number of subnodes (ie "cpu")
+defining properties for every cpu.
+
+Only SMP system need to care about the cpus node and single processor
+needn't define cpus node at all.
+
+=====================================
+cpus and cpu node bindings definition
+=====================================
+
+- cpus node
+
+	Description: Container of cpu nodes
+
+	The node name must be "cpus".
+
+	A cpus node must define the following properties:
+
+	- #address-cells
+		Usage: required
+		Value type: <u32>
+		Definition: must be set to 1
+	- #size-cells
+		Usage: required
+		Value type: <u32>
+		Definition: must be set to 0
+
+- cpu node
+
+	Description: Describes one of SMP cores
+
+	PROPERTIES
+
+	- device_type
+		Usage: required
+		Value type: <string>
+		Definition: must be "cpu"
+	- reg
+		Usage: required
+		Value type: <u32>
+		Definition: CPU index
+	- compatible:
+		Usage: required
+		Value type: <string>
+		Definition: must contain "csky", eg:
+			"csky,610"
+			"csky,807"
+			"csky,810"
+			"csky,860"
+
+Example:
+--------
+
+	cpus {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		cpu@0 {
+			device_type = "cpu";
+			reg = <0>;
+			status = "ok";
+		};
+
+		cpu@1 {
+			device_type = "cpu";
+			reg = <1>;
+			status = "ok";
+		};
+	};

Documentation/devicetree/bindings/interrupt-controller/csky,apb-intc.txt

@@ -0,0 +1,62 @@
+==============================
+C-SKY APB Interrupt Controller
+==============================
+
+C-SKY APB Interrupt Controller is a simple soc interrupt controller
+on the apb bus and we only use it as root irq controller.
+
+ - csky,apb-intc is used in a lot of csky fpgas and socs, it support 64 irq nums.
+ - csky,dual-apb-intc consists of 2 apb-intc and 128 irq nums supported.
+ - csky,gx6605s-intc is gx6605s soc internal irq interrupt controller, 64 irq nums.
+
+=============================
+intc node bindings definition
+=============================
+
+	Description: Describes APB interrupt controller
+
+	PROPERTIES
+
+	- compatible
+		Usage: required
+		Value type: <string>
+		Definition: must be "csky,apb-intc"
+				    "csky,dual-apb-intc"
+				    "csky,gx6605s-intc"
+	- #interrupt-cells
+		Usage: required
+		Value type: <u32>
+		Definition: must be <1>
+	- reg
+		Usage: required
+		Value type: <u32 u32>
+		Definition: <phyaddr size> in soc from cpu view
+	- interrupt-controller:
+		Usage: required
+	- csky,support-pulse-signal:
+		Usage: select
+		Description: to support pulse signal flag
+
+Examples:
+---------
+
+	intc: interrupt-controller@500000 {
+		compatible = "csky,apb-intc";
+		#interrupt-cells = <1>;
+		reg = <0x00500000 0x400>;
+		interrupt-controller;
+	};
+
+	intc: interrupt-controller@500000 {
+		compatible = "csky,dual-apb-intc";
+		#interrupt-cells = <1>;
+		reg = <0x00500000 0x400>;
+		interrupt-controller;
+	};
+
+	intc: interrupt-controller@500000 {
+		compatible = "csky,gx6605s-intc";
+		#interrupt-cells = <1>;
+		reg = <0x00500000 0x400>;
+		interrupt-controller;
+	};

Documentation/devicetree/bindings/interrupt-controller/csky,mpintc.txt

@@ -0,0 +1,40 @@
+===========================================
+C-SKY Multi-processors Interrupt Controller
+===========================================
+
+C-SKY Multi-processors Interrupt Controller is designed for ck807/ck810/ck860
+SMP soc, and it also could be used in non-SMP system.
+
+Interrupt number definition:
+
+  0-15  : software irq, and we use 15 as our IPI_IRQ.
+ 16-31  : private  irq, and we use 16 as the co-processor timer.
+ 31-1024: common irq for soc ip.
+
+=============================
+intc node bindings definition
+=============================
+
+	Description: Describes SMP interrupt controller
+
+	PROPERTIES
+
+	- compatible
+		Usage: required
+		Value type: <string>
+		Definition: must be "csky,mpintc"
+	- #interrupt-cells
+		Usage: required
+		Value type: <u32>
+		Definition: must be <1>
+	- interrupt-controller:
+		Usage: required
+
+Examples:
+---------
+
+	intc: interrupt-controller {
+		compatible = "csky,mpintc";
+		#interrupt-cells = <1>;
+		interrupt-controller;
+	};

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -84,6 +84,7 @@ cosmic	Cosmic Circuits
 crane	Crane Connectivity Solutions
 creative	Creative Technology Ltd
 crystalfontz	Crystalfontz America, Inc.
+csky	Hangzhou C-SKY Microsystems Co., Ltd
 cubietech	Cubietech, Ltd.
 cypress	Cypress Semiconductor Corporation
 cznic	CZ.NIC, z.s.p.o.

MAINTAINERS

@@ -3229,6 +3229,15 @@ T:	git git://git.alsa-project.org/alsa-kernel.git
 S:	Maintained
 F:	sound/pci/oxygen/
 
+C-SKY ARCHITECTURE
+M:	Guo Ren <ren_guo@c-sky.com>
+T:	git https://github.com/c-sky/csky-linux.git
+S:	Supported
+F:	arch/csky/
+F:	Documentation/devicetree/bindings/csky/
+K:	csky
+N:	csky
+
 C6X ARCHITECTURE
 M:	Mark Salter <msalter@redhat.com>
 M:	Aurelien Jacquiot <jacquiot.aurelien@gmail.com>