27 files changed, 625 insertions, 59 deletions

diff --git a/Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt b/Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt
new file mode 100644
index 000000000000..b0a8af51c388
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt
@@ -0,0 +1,44 @@
+RISC-V Hart-Level Interrupt Controller (HLIC)
+---------------------------------------------
+
+RISC-V cores include Control Status Registers (CSRs) which are local to each
+CPU core (HART in RISC-V terminology) and can be read or written by software.
+Some of these CSRs are used to control local interrupts connected to the core.
+Every interrupt is ultimately routed through a hart's HLIC before it
+interrupts that hart.
+
+The RISC-V supervisor ISA manual specifies three interrupt sources that are
+attached to every HLIC: software interrupts, the timer interrupt, and external
+interrupts.  Software interrupts are used to send IPIs between cores.  The
+timer interrupt comes from an architecturally mandated real-time timer that is
+controller via Supervisor Binary Interface (SBI) calls and CSR reads.  External
+interrupts connect all other device interrupts to the HLIC, which are routed
+via the platform-level interrupt controller (PLIC).
+
+All RISC-V systems that conform to the supervisor ISA specification are
+required to have a HLIC with these three interrupt sources present.  Since the
+interrupt map is defined by the ISA it's not listed in the HLIC's device tree
+entry, though external interrupt controllers (like the PLIC, for example) will
+need to define how their interrupts map to the relevant HLICs.  This means
+a PLIC interrupt property will typically list the HLICs for all present HARTs
+in the system.
+
+Required properties:
+- compatible : "riscv,cpu-intc"
+- #interrupt-cells : should be <1>
+- interrupt-controller : Identifies the node as an interrupt controller
+
+Furthermore, this interrupt-controller MUST be embedded inside the cpu
+definition of the hart whose CSRs control these local interrupts.
+
+An example device tree entry for a HLIC is show below.
+
+        cpu1: cpu@1 {
+                compatible = "riscv";
+                ...
+                cpu1-intc: interrupt-controller {
+                        #interrupt-cells = <1>;
+                        compatible = "riscv,cpu-intc", "sifive,fu540-c000-cpu-intc";
+                        interrupt-controller;
+                };
+        };
diff --git a/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.txt b/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.txt
new file mode 100644
index 000000000000..6adf7a6e8825
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.txt
@@ -0,0 +1,58 @@
+SiFive Platform-Level Interrupt Controller (PLIC)
+-------------------------------------------------
+
+SiFive SOCs include an implementation of the Platform-Level Interrupt Controller
+(PLIC) high-level specification in the RISC-V Privileged Architecture
+specification.  The PLIC connects all external interrupts in the system to all
+hart contexts in the system, via the external interrupt source in each hart.
+
+A hart context is a privilege mode in a hardware execution thread.  For example,
+in an 4 core system with 2-way SMT, you have 8 harts and probably at least two
+privilege modes per hart; machine mode and supervisor mode.
+
+Each interrupt can be enabled on per-context basis.  Any context can claim
+a pending enabled interrupt and then release it once it has been handled.
+
+Each interrupt has a configurable priority.  Higher priority interrupts are
+serviced first.  Each context can specify a priority threshold. Interrupts
+with priority below this threshold will not cause the PLIC to raise its
+interrupt line leading to the context.
+
+While the PLIC supports both edge-triggered and level-triggered interrupts,
+interrupt handlers are oblivious to this distinction and therefore it is not
+specified in the PLIC device-tree binding.
+
+While the RISC-V ISA doesn't specify a memory layout for the PLIC, the
+"sifive,plic-1.0.0" device is a concrete implementation of the PLIC that
+contains a specific memory layout, which is documented in chapter 8 of the
+SiFive U5 Coreplex Series Manual <https://static.dev.sifive.com/U54-MC-RVCoreIP.pdf>.
+
+Required properties:
+- compatible : "sifive,plic-1.0.0" and a string identifying the actual
+  detailed implementation in case that specific bugs need to be worked around.
+- #address-cells : should be <0> or more.
+- #interrupt-cells : should be <1> or more.
+- interrupt-controller : Identifies the node as an interrupt controller.
+- reg : Should contain 1 register range (address and length).
+- interrupts-extended : Specifies which contexts are connected to the PLIC,
+  with "-1" specifying that a context is not present.  Each node pointed
+  to should be a riscv,cpu-intc node, which has a riscv node as parent.
+- riscv,ndev: Specifies how many external interrupts are supported by
+  this controller.
+
+Example:
+
+        plic: interrupt-controller@c000000 {
+                #address-cells = <0>;
+                #interrupt-cells = <1>;
+                compatible = "sifive,plic-1.0.0", "sifive,fu540-c000-plic";
+                interrupt-controller;
+                interrupts-extended = <
+                        &cpu0-intc 11
+                        &cpu1-intc 11 &cpu1-intc 9
+                        &cpu2-intc 11 &cpu2-intc 9
+                        &cpu3-intc 11 &cpu3-intc 9
+                        &cpu4-intc 11 &cpu4-intc 9>;
+                reg = <0xc000000 0x4000000>;
+                riscv,ndev = <10>;
+        };
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 2627e4813edf..9ddd88bb30b7 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -25,6 +25,9 @@ ifeq ($(CONFIG_ARCH_RV64I),y)
 
         KBUILD_CFLAGS += -mabi=lp64
         KBUILD_AFLAGS += -mabi=lp64
+        
+        KBUILD_CFLAGS   += $(call cc-ifversion, -ge, 0500, -DCONFIG_ARCH_SUPPORTS_INT128)
+
         KBUILD_MARCH = rv64im
         LDFLAGS += -melf64lriscv
 else
diff --git a/arch/riscv/configs/defconfig b/arch/riscv/configs/defconfig
index 07326466871b..36473d7dbaac 100644
--- a/arch/riscv/configs/defconfig
+++ b/arch/riscv/configs/defconfig
@@ -76,3 +76,4 @@ CONFIG_ROOT_NFS=y
 CONFIG_CRYPTO_USER_API_HASH=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
+CONFIG_SIFIVE_PLIC=y
diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index 421fa3585798..28a0d1cb374c 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -54,6 +54,7 @@
 /* Interrupt Enable and Interrupt Pending flags */
 #define SIE_SSIE _AC(0x00000002, UL) /* Software Interrupt Enable */
 #define SIE_STIE _AC(0x00000020, UL) /* Timer Interrupt Enable */
+#define SIE_SEIE _AC(0x00000200, UL) /* External Interrupt Enable */
 
 #define EXC_INST_MISALIGNED     0
 #define EXC_INST_ACCESS         1
diff --git a/arch/riscv/include/asm/irq.h b/arch/riscv/include/asm/irq.h
index 4dee9d4c13c0..996b6fbe17a6 100644
--- a/arch/riscv/include/asm/irq.h
+++ b/arch/riscv/include/asm/irq.h
@@ -17,11 +17,8 @@
 
 #define NR_IRQS         0
 
-#define INTERRUPT_CAUSE_SOFTWARE    1
-#define INTERRUPT_CAUSE_TIMER       5
-#define INTERRUPT_CAUSE_EXTERNAL    9
-