diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 36512a8995..4d7a115569 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -120,4 +120,23 @@ config RISCV_RDTIME
config SYS_MALLOC_F_LEN
default 0x1000
+config SMP
+ bool "Symmetric Multi-Processing"
+ help
+ This enables support for systems with more than one CPU. If
+ you say N here, U-Boot will run on single and multiprocessor
+ machines, but will use only one CPU of a multiprocessor
+ machine. If you say Y here, U-Boot will run on many, but not
+ all, single processor machines.
+
+config NR_CPUS
+ int "Maximum number of CPUs (2-32)"
+ range 2 32
+ depends on SMP
+ default 8
+ help
+ On multiprocessor machines, U-Boot sets up a stack for each CPU.
+ Stack memory is pre-allocated. U-Boot must therefore know the
+ maximum number of CPUs that may be present.
+
endmenu
diff --git a/arch/riscv/include/asm/global_data.h b/arch/riscv/include/asm/global_data.h
index a3a342c6e1..80e3165e39 100644
--- a/arch/riscv/include/asm/global_data.h
+++ b/arch/riscv/include/asm/global_data.h
@@ -10,12 +10,18 @@
#ifndef __ASM_GBL_DATA_H
#define __ASM_GBL_DATA_H
+#include <asm/smp.h>
+
/* Architecture-specific global data */
struct arch_global_data {
long boot_hart; /* boot hart id */
#ifdef CONFIG_SIFIVE_CLINT
void __iomem *clint; /* clint base address */
#endif
+#ifdef CONFIG_SMP
+ struct ipi_data ipi[CONFIG_NR_CPUS];
+#endif
+ ulong available_harts;
};
#include <asm-generic/global_data.h>
diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
new file mode 100644
index 0000000000..bc863fdbaf
--- /dev/null
+++ b/arch/riscv/include/asm/smp.h
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 Fraunhofer AISEC,
+ * Lukas Auer <lukas.auer@aisec.fraunhofer.de>
+ */
+
+#ifndef _ASM_RISCV_SMP_H
+#define _ASM_RISCV_SMP_H
+
+/**
+ * struct ipi_data - Inter-processor interrupt (IPI) data structure
+ *
+ * IPIs are used for SMP support to communicate to other harts what function to
+ * call. Functions are in the form
+ * void (*addr)(ulong hart, ulong arg0, ulong arg1).
+ *
+ * The function address and the two arguments, arg0 and arg1, are stored in the
+ * IPI data structure. The hart ID is inserted by the hart handling the IPI and
+ * calling the function.
+ *
+ * @addr: Address of function
+ * @arg0: First argument of function
+ * @arg1: Second argument of function
+ */
+struct ipi_data {
+ ulong addr;
+ ulong arg0;
+ ulong arg1;
+};
+
+/**
+ * handle_ipi() - interrupt handler for software interrupts
+ *
+ * The IPI interrupt handler must be called to handle software interrupts. It
+ * calls the function specified in the hart's IPI data structure.
+ *
+ * @hart: Hart ID of the current hart
+ */
+void handle_ipi(ulong hart);
+
+/**
+ * smp_call_function() - Call a function on all other harts
+ *
+ * Send IPIs with the specified function call to all harts.
+ *
+ * @addr: Address of function
+ * @arg0: First argument of function
+ * @arg1: Second argument of function
+ * @return 0 if OK, -ve on error
+ */
+int smp_call_function(ulong addr, ulong arg0, ulong arg1);
+
+#endif
diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index edfa61690c..19370f9749 100644
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_SIFIVE_CLINT) += sifive_clint.o
obj-y += interrupts.o
obj-y += reset.o
obj-y += setjmp.o
+obj-$(CONFIG_SMP) += smp.o
# For building EFI apps
CFLAGS_$(EFI_CRT0) := $(CFLAGS_EFI)
diff --git a/arch/riscv/lib/smp.c b/arch/riscv/lib/smp.c
new file mode 100644
index 0000000000..caa292ccd2
--- /dev/null
+++ b/arch/riscv/lib/smp.c
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Fraunhofer AISEC,
+ * Lukas Auer <lukas.auer@aisec.fraunhofer.de>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <asm/barrier.h>
+#include <asm/smp.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/**
+ * riscv_send_ipi() - Send inter-processor interrupt (IPI)
+ *
+ * Platform code must provide this function.
+ *
+ * @hart: Hart ID of receiving hart
+ * @return 0 if OK, -ve on error
+ */
+extern int riscv_send_ipi(int hart);
+
+/**
+ * riscv_clear_ipi() - Clear inter-processor interrupt (IPI)
+ *
+ * Platform code must provide this function.
+ *
+ * @hart: Hart ID of hart to be cleared
+ * @return 0 if OK, -ve on error
+ */
+extern int riscv_clear_ipi(int hart);
+
+static int send_ipi_many(struct ipi_data *ipi)
+{
+ ofnode node, cpus;
+ u32 reg;
+ int ret;
+
+ cpus = ofnode_path("/cpus");
+ if (!ofnode_valid(cpus)) {
+ pr_err("Can't find cpus node!\n");
+ return -EINVAL;
+ }
+
+ ofnode_for_each_subnode(node, cpus) {
+ /* skip if hart is marked as not available in the device tree */
+ if (!ofnode_is_available(node))
+ continue;
+
+ /* read hart ID of CPU */
+ ret = ofnode_read_u32(node, "reg", ®);
+ if (ret)
+ continue;
+
+ /* skip if it is the hart we are running on */
+ if (reg == gd->arch.boot_hart)
+ continue;
+
+ if (reg >= CONFIG_NR_CPUS) {
+ pr_err("Hart ID %d is out of range, increase CONFIG_NR_CPUS\n",
+ reg);
+ continue;
+ }
+
+ /* skip if hart is not available */
+ if (!(gd->arch.available_harts & (1 << reg)))
+ continue;
+
+ gd->arch.ipi[reg].addr = ipi->addr;
+ gd->arch.ipi[reg].arg0 = ipi->arg0;
+ gd->arch.ipi[reg].arg1 = ipi->arg1;
+
+ ret = riscv_send_ipi(reg);
+ if (ret) {
+ pr_err("Cannot send IPI to hart %d\n", reg);
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+void handle_ipi(ulong hart)
+{
+ int ret;
+ void (*smp_function)(ulong hart, ulong arg0, ulong arg1);
+
+ if (hart >= CONFIG_NR_CPUS)
+ return;
+
+ ret = riscv_clear_ipi(hart);
+ if (ret) {
+ pr_err("Cannot clear IPI of hart %ld\n", hart);
+ return;
+ }
+
+ __smp_mb();
+
+ smp_function = (void (*)(ulong, ulong, ulong))gd->arch.ipi[hart].addr;
+ invalidate_icache_all();
+
+ smp_function(hart, gd->arch.ipi[hart].arg0, gd->arch.ipi[hart].arg1);
+}
+
+int smp_call_function(ulong addr, ulong arg0, ulong arg1)
+{
+ int ret = 0;
+ struct ipi_data ipi;
+
+ ipi.addr = addr;
+ ipi.arg0 = arg0;
+ ipi.arg1 = arg1;
+
+ ret = send_ipi_many(&ipi);
+
+ return ret;
+}