diff --git a/drivers/allwinner/sunxi_rsb.c b/drivers/allwinner/sunxi_rsb.c
new file mode 100644
index 0000000..7075c67
--- /dev/null
+++ b/drivers/allwinner/sunxi_rsb.c
@@ -0,0 +1,136 @@
+/*
+ * Copyright (c) 2017-2018 ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <debug.h>
+#include <delay_timer.h>
+#include <errno.h>
+#include <mmio.h>
+#include <sunxi_mmap.h>
+
+#define RSB_CTRL	0x00
+#define RSB_CCR		0x04
+#define RSB_INTE	0x08
+#define RSB_STAT	0x0c
+#define RSB_DADDR0	0x10
+#define RSB_DLEN	0x18
+#define RSB_DATA0	0x1c
+#define RSB_LCR		0x24
+#define RSB_PMCR	0x28
+#define RSB_CMD		0x2c
+#define RSB_SADDR	0x30
+
+#define RSBCMD_SRTA	0xE8
+#define RSBCMD_RD8	0x8B
+#define RSBCMD_RD16	0x9C
+#define RSBCMD_RD32	0xA6
+#define RSBCMD_WR8	0x4E
+#define RSBCMD_WR16	0x59
+#define RSBCMD_WR32	0x63
+
+#define MAX_TRIES	100000
+
+static int rsb_wait_bit(const char *desc, unsigned int offset, uint32_t mask)
+{
+	uint32_t reg, tries = MAX_TRIES;
+
+	do
+		reg = mmio_read_32(SUNXI_R_RSB_BASE + offset);
+	while ((reg & mask) && --tries);	/* transaction in progress */
+	if (reg & mask) {
+		ERROR("%s: timed out\n", desc);
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int rsb_wait_stat(const char *desc)
+{
+	uint32_t reg;
+	int ret = rsb_wait_bit(desc, RSB_CTRL, BIT(7));
+
+	if (ret)
+		return ret;
+
+	reg = mmio_read_32(SUNXI_R_RSB_BASE + RSB_STAT);
+	if (reg == 0x01)
+		return 0;
+
+	ERROR("%s: 0x%x\n", desc, reg);
+	return -reg;
+}
+
+/* Initialize the RSB controller. */
+int rsb_init_controller(void)
+{
+	mmio_write_32(SUNXI_R_RSB_BASE + RSB_CTRL, 0x01); /* soft reset */
+
+	return rsb_wait_bit("RSB: reset controller", RSB_CTRL, BIT(0));
+}
+
+int rsb_read(uint8_t rt_addr, uint8_t reg_addr)
+{
+	int ret;
+
+	mmio_write_32(SUNXI_R_RSB_BASE + RSB_CMD, RSBCMD_RD8); /* read a byte */
+	mmio_write_32(SUNXI_R_RSB_BASE + RSB_SADDR, rt_addr << 16);
+	mmio_write_32(SUNXI_R_RSB_BASE + RSB_DADDR0, reg_addr);
+	mmio_write_32(SUNXI_R_RSB_BASE + RSB_CTRL, 0x80);/* start transaction */
+
+	ret = rsb_wait_stat("RSB: read command");
+	if (ret)
+		return ret;
+
+	return mmio_read_32(SUNXI_R_RSB_BASE + RSB_DATA0) & 0xff; /* result */
+}
+
+int rsb_write(uint8_t rt_addr, uint8_t reg_addr, uint8_t value)
+{
+	mmio_write_32(SUNXI_R_RSB_BASE + RSB_CMD, RSBCMD_WR8);	/* byte write */
+	mmio_write_32(SUNXI_R_RSB_BASE + RSB_SADDR, rt_addr << 16);
+	mmio_write_32(SUNXI_R_RSB_BASE + RSB_DADDR0, reg_addr);
+	mmio_write_32(SUNXI_R_RSB_BASE + RSB_DATA0, value);
+	mmio_write_32(SUNXI_R_RSB_BASE + RSB_CTRL, 0x80);/* start transaction */
+
+	return rsb_wait_stat("RSB: write command");
+}
+
+int rsb_set_device_mode(uint32_t device_mode)
+{
+	mmio_write_32(SUNXI_R_RSB_BASE + RSB_PMCR,
+		      (device_mode & 0x00ffffff) | BIT(31));
+
+	return rsb_wait_bit("RSB: set device to RSB", RSB_PMCR, BIT(31));
+}
+
+int rsb_set_bus_speed(uint32_t source_freq, uint32_t bus_freq)
+{
+	uint32_t reg;
+
+	if (bus_freq == 0)
+		return -EINVAL;
+
+	reg = source_freq / bus_freq;
+	if (reg < 2)
+		return -EINVAL;
+
+	reg = reg / 2 - 1;
+	reg |= (1U << 8);		/* one cycle of CD output delay */
+
+	mmio_write_32(SUNXI_R_RSB_BASE + RSB_CCR, reg);
+
+	return 0;
+}
+
+/* Initialize the RSB PMIC connection. */
+int rsb_assign_runtime_address(uint16_t hw_addr, uint8_t rt_addr)
+{
+	mmio_write_32(SUNXI_R_RSB_BASE + RSB_SADDR, hw_addr | (rt_addr << 16));
+	mmio_write_32(SUNXI_R_RSB_BASE + RSB_CMD, RSBCMD_SRTA);
+	mmio_write_32(SUNXI_R_RSB_BASE + RSB_CTRL, 0x80);
+
+	return rsb_wait_stat("RSB: set run-time address");
+}