feat(drivers/arm/mhu): add MHU driver
The Arm Message Handling Unit (MHU) is a mailbox controller used to
communicate with other processing element(s). Adding a driver to
enable the communication:
- Adding generic MHU driver interface,
- Adding MHU_v2_x driver.
Driver supports:
- Discovering available MHU channels,
- Sending / receiving words over MHU channels,
- Signaling happens over a dedicated channel.
Signed-off-by: Tamas Ban <tamas.ban@arm.com>
Signed-off-by: David Vincze <david.vincze@arm.com>
Change-Id: I41a5b968f6b8319cdbdf7907d70bd8837839862e
diff --git a/drivers/arm/mhu/mhu_v2_x.c b/drivers/arm/mhu/mhu_v2_x.c
new file mode 100644
index 0000000..3103b92
--- /dev/null
+++ b/drivers/arm/mhu/mhu_v2_x.c
@@ -0,0 +1,379 @@
+/*
+ * Copyright (c) 2020-2022, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "mhu_v2_x.h"
+
+#define MHU_V2_X_MAX_CHANNELS 124
+#define MHU_V2_1_MAX_CHCOMB_INT 4
+#define ENABLE 0x1
+#define DISABLE 0x0
+#define CLEAR_INTR 0x1
+#define CH_PER_CH_COMB 0x20
+#define SEND_FRAME(p_mhu) ((struct mhu_v2_x_send_frame_t *)p_mhu)
+#define RECV_FRAME(p_mhu) ((struct mhu_v2_x_recv_frame_t *)p_mhu)
+
+#define MHU_MAJOR_REV_V2 0x1u
+#define MHU_MINOR_REV_2_0 0x0u
+#define MHU_MINOR_REV_2_1 0x1u
+
+struct mhu_v2_x_send_ch_window_t {
+ /* Offset: 0x00 (R/ ) Channel Status */
+ volatile uint32_t ch_st;
+ /* Offset: 0x04 (R/ ) Reserved */
+ volatile uint32_t reserved_0;
+ /* Offset: 0x08 (R/ ) Reserved */
+ volatile uint32_t reserved_1;
+ /* Offset: 0x0C ( /W) Channel Set */
+ volatile uint32_t ch_set;
+ /* Offset: 0x10 (R/ ) Channel Interrupt Status (Reserved in 2.0) */
+ volatile uint32_t ch_int_st;
+ /* Offset: 0x14 ( /W) Channel Interrupt Clear (Reserved in 2.0) */
+ volatile uint32_t ch_int_clr;
+ /* Offset: 0x18 (R/W) Channel Interrupt Enable (Reserved in 2.0) */
+ volatile uint32_t ch_int_en;
+ /* Offset: 0x1C (R/ ) Reserved */
+ volatile uint32_t reserved_2;
+};
+
+struct mhu_v2_x_send_frame_t {
+ /* Offset: 0x000 ( / ) Sender Channel Window 0 -123 */
+ struct mhu_v2_x_send_ch_window_t send_ch_window[MHU_V2_X_MAX_CHANNELS];
+ /* Offset: 0xF80 (R/ ) Message Handling Unit Configuration */
+ volatile uint32_t mhu_cfg;
+ /* Offset: 0xF84 (R/W) Response Configuration */
+ volatile uint32_t resp_cfg;
+ /* Offset: 0xF88 (R/W) Access Request */
+ volatile uint32_t access_request;
+ /* Offset: 0xF8C (R/ ) Access Ready */
+ volatile uint32_t access_ready;
+ /* Offset: 0xF90 (R/ ) Interrupt Status */
+ volatile uint32_t int_st;
+ /* Offset: 0xF94 ( /W) Interrupt Clear */
+ volatile uint32_t int_clr;
+ /* Offset: 0xF98 (R/W) Interrupt Enable */
+ volatile uint32_t int_en;
+ /* Offset: 0xF9C (R/ ) Reserved */
+ volatile uint32_t reserved_0;
+ /* Offset: 0xFA0 (R/W) Channel Combined IRQ Stat (Reserved in 2.0) */
+ volatile uint32_t ch_comb_int_st[MHU_V2_1_MAX_CHCOMB_INT];
+ /* Offset: 0xFC4 (R/ ) Reserved */
+ volatile uint32_t reserved_1[6];
+ /* Offset: 0xFC8 (R/ ) Implementer Identification Register */
+ volatile uint32_t iidr;
+ /* Offset: 0xFCC (R/ ) Architecture Identification Register */
+ volatile uint32_t aidr;
+ /* Offset: 0xFD0 (R/ ) */
+ volatile uint32_t pid_1[4];
+ /* Offset: 0xFE0 (R/ ) */
+ volatile uint32_t pid_0[4];
+ /* Offset: 0xFF0 (R/ ) */
+ volatile uint32_t cid[4];
+};
+
+struct mhu_v2_x_rec_ch_window_t {
+ /* Offset: 0x00 (R/ ) Channel Status */
+ volatile uint32_t ch_st;
+ /* Offset: 0x04 (R/ ) Channel Status Masked */
+ volatile uint32_t ch_st_msk;
+ /* Offset: 0x08 ( /W) Channel Clear */
+ volatile uint32_t ch_clr;
+ /* Offset: 0x0C (R/ ) Reserved */
+ volatile uint32_t reserved_0;
+ /* Offset: 0x10 (R/ ) Channel Mask Status */
+ volatile uint32_t ch_msk_st;
+ /* Offset: 0x14 ( /W) Channel Mask Set */
+ volatile uint32_t ch_msk_set;
+ /* Offset: 0x18 ( /W) Channel Mask Clear */
+ volatile uint32_t ch_msk_clr;
+ /* Offset: 0x1C (R/ ) Reserved */
+ volatile uint32_t reserved_1;
+};
+
+struct mhu_v2_x_recv_frame_t {
+ /* Offset: 0x000 ( / ) Receiver Channel Window 0 -123 */
+ struct mhu_v2_x_rec_ch_window_t rec_ch_window[MHU_V2_X_MAX_CHANNELS];
+ /* Offset: 0xF80 (R/ ) Message Handling Unit Configuration */
+ volatile uint32_t mhu_cfg;
+ /* Offset: 0xF84 (R/ ) Reserved */
+ volatile uint32_t reserved_0[3];
+ /* Offset: 0xF90 (R/ ) Interrupt Status (Reserved in 2.0) */
+ volatile uint32_t int_st;
+ /* Offset: 0xF94 (R/ ) Interrupt Clear (Reserved in 2.0) */
+ volatile uint32_t int_clr;
+ /* Offset: 0xF98 (R/W) Interrupt Enable (Reserved in 2.0) */
+ volatile uint32_t int_en;
+ /* Offset: 0xF9C (R/ ) Reserved */
+ volatile uint32_t reserved_1;
+ /* Offset: 0xFA0 (R/ ) Channel Combined IRQ Stat (Reserved in 2.0) */
+ volatile uint32_t ch_comb_int_st[MHU_V2_1_MAX_CHCOMB_INT];
+ /* Offset: 0xFB0 (R/ ) Reserved */
+ volatile uint32_t reserved_2[6];
+ /* Offset: 0xFC8 (R/ ) Implementer Identification Register */
+ volatile uint32_t iidr;
+ /* Offset: 0xFCC (R/ ) Architecture Identification Register */
+ volatile uint32_t aidr;
+ /* Offset: 0xFD0 (R/ ) */
+ volatile uint32_t pid_1[4];
+ /* Offset: 0xFE0 (R/ ) */
+ volatile uint32_t pid_0[4];
+ /* Offset: 0xFF0 (R/ ) */
+ volatile uint32_t cid[4];
+};
+
+union mhu_v2_x_frame {
+ struct mhu_v2_x_send_frame_t send_frame;
+ struct mhu_v2_x_recv_frame_t recv_frame;
+};
+
+enum mhu_v2_x_error_t mhu_v2_x_driver_init(struct mhu_v2_x_dev_t *dev,
+ enum mhu_v2_x_supported_revisions rev)
+{
+ uint32_t AIDR = 0;
+ union mhu_v2_x_frame *p_mhu;
+
+ assert(dev != NULL);
+
+ p_mhu = (union mhu_v2_x_frame *)dev->base;
+
+ if (dev->is_initialized) {
+ return MHU_V_2_X_ERR_ALREADY_INIT;
+ }
+
+ if (rev == MHU_REV_READ_FROM_HW) {
+ /* Read revision from HW */
+ if (dev->frame == MHU_V2_X_RECEIVER_FRAME) {
+ AIDR = p_mhu->recv_frame.aidr;
+ } else {
+ AIDR = p_mhu->send_frame.aidr;
+ }
+
+ /* Get bits 7:4 to read major revision */
+ if (((AIDR >> 4) & 0b1111) != MHU_MAJOR_REV_V2) {
+ /* Unsupported MHU version */
+ return MHU_V_2_X_ERR_UNSUPPORTED_VERSION;
+ } /* No need to save major version, driver only supports MHUv2 */
+
+ /* Get bits 3:0 to read minor revision */
+ dev->subversion = AIDR & 0b1111;
+
+ if (dev->subversion != MHU_MINOR_REV_2_0 &&
+ dev->subversion != MHU_MINOR_REV_2_1) {
+ /* Unsupported subversion */
+ return MHU_V_2_X_ERR_UNSUPPORTED_VERSION;
+ }
+ } else {
+ /* Revisions were provided by caller */
+ if (rev == MHU_REV_2_0) {
+ dev->subversion = MHU_MINOR_REV_2_0;
+ } else if (rev == MHU_REV_2_1) {
+ dev->subversion = MHU_MINOR_REV_2_1;
+ } else {
+ /* Unsupported subversion */
+ return MHU_V_2_X_ERR_UNSUPPORTED_VERSION;
+ } /* No need to save major version, driver only supports MHUv2 */
+ }
+
+ dev->is_initialized = true;
+
+ return MHU_V_2_X_ERR_NONE;
+}
+
+uint32_t mhu_v2_x_get_num_channel_implemented(const struct mhu_v2_x_dev_t *dev)
+{
+ union mhu_v2_x_frame *p_mhu;
+
+ assert(dev != NULL);
+
+ p_mhu = (union mhu_v2_x_frame *)dev->base;
+
+ if (!(dev->is_initialized)) {
+ return MHU_V_2_X_ERR_NOT_INIT;
+ }
+
+ if (dev->frame == MHU_V2_X_SENDER_FRAME) {
+ return (SEND_FRAME(p_mhu))->mhu_cfg;
+ } else {
+ assert(dev->frame == MHU_V2_X_RECEIVER_FRAME);
+ return (RECV_FRAME(p_mhu))->mhu_cfg;
+ }
+}
+
+enum mhu_v2_x_error_t mhu_v2_x_channel_send(const struct mhu_v2_x_dev_t *dev,
+ uint32_t channel, uint32_t val)
+{
+ union mhu_v2_x_frame *p_mhu;
+
+ assert(dev != NULL);
+
+ p_mhu = (union mhu_v2_x_frame *)dev->base;
+
+ if (!(dev->is_initialized)) {
+ return MHU_V_2_X_ERR_NOT_INIT;
+ }
+
+ if (dev->frame == MHU_V2_X_SENDER_FRAME) {
+ (SEND_FRAME(p_mhu))->send_ch_window[channel].ch_set = val;
+ return MHU_V_2_X_ERR_NONE;
+ } else {
+ return MHU_V_2_X_ERR_INVALID_ARG;
+ }
+}
+
+enum mhu_v2_x_error_t mhu_v2_x_channel_poll(const struct mhu_v2_x_dev_t *dev,
+ uint32_t channel, uint32_t *value)
+{
+ union mhu_v2_x_frame *p_mhu;
+
+ assert(dev != NULL);
+
+ p_mhu = (union mhu_v2_x_frame *)dev->base;
+
+ if (!(dev->is_initialized)) {
+ return MHU_V_2_X_ERR_NOT_INIT;
+ }
+
+ if (dev->frame == MHU_V2_X_SENDER_FRAME) {
+ *value = (SEND_FRAME(p_mhu))->send_ch_window[channel].ch_st;
+ return MHU_V_2_X_ERR_NONE;
+ } else {
+ return MHU_V_2_X_ERR_INVALID_ARG;
+ }
+}
+
+enum mhu_v2_x_error_t mhu_v2_x_channel_clear(const struct mhu_v2_x_dev_t *dev,
+ uint32_t channel)
+{
+ union mhu_v2_x_frame *p_mhu;
+
+ assert(dev != NULL);
+
+ p_mhu = (union mhu_v2_x_frame *)dev->base;
+
+ if (!(dev->is_initialized)) {
+ return MHU_V_2_X_ERR_NOT_INIT;
+ }
+
+ if (dev->frame == MHU_V2_X_RECEIVER_FRAME) {
+ (RECV_FRAME(p_mhu))->rec_ch_window[channel].ch_clr = UINT32_MAX;
+ return MHU_V_2_X_ERR_NONE;
+ } else {
+ return MHU_V_2_X_ERR_INVALID_ARG;
+ }
+}
+
+enum mhu_v2_x_error_t mhu_v2_x_channel_receive(
+ const struct mhu_v2_x_dev_t *dev, uint32_t channel, uint32_t *value)
+{
+ union mhu_v2_x_frame *p_mhu;
+
+ assert(dev != NULL);
+
+ p_mhu = (union mhu_v2_x_frame *)dev->base;
+
+ if (!(dev->is_initialized)) {
+ return MHU_V_2_X_ERR_NOT_INIT;
+ }
+
+ if (dev->frame == MHU_V2_X_RECEIVER_FRAME) {
+ *value = (RECV_FRAME(p_mhu))->rec_ch_window[channel].ch_st;
+ return MHU_V_2_X_ERR_NONE;
+ } else {
+ return MHU_V_2_X_ERR_INVALID_ARG;
+ }
+}
+
+enum mhu_v2_x_error_t mhu_v2_x_channel_mask_set(
+ const struct mhu_v2_x_dev_t *dev, uint32_t channel, uint32_t mask)
+{
+ union mhu_v2_x_frame *p_mhu;
+
+ assert(dev != NULL);
+
+ p_mhu = (union mhu_v2_x_frame *)dev->base;
+
+ if (!(dev->is_initialized)) {
+ return MHU_V_2_X_ERR_NOT_INIT;
+ }
+
+ if (dev->frame == MHU_V2_X_RECEIVER_FRAME) {
+ (RECV_FRAME(p_mhu))->rec_ch_window[channel].ch_msk_set = mask;
+ return MHU_V_2_X_ERR_NONE;
+ } else {
+ return MHU_V_2_X_ERR_INVALID_ARG;
+ }
+}
+
+enum mhu_v2_x_error_t mhu_v2_x_channel_mask_clear(
+ const struct mhu_v2_x_dev_t *dev, uint32_t channel, uint32_t mask)
+{
+ union mhu_v2_x_frame *p_mhu;
+
+ assert(dev != NULL);
+
+ p_mhu = (union mhu_v2_x_frame *)dev->base;
+
+ if (!(dev->is_initialized)) {
+ return MHU_V_2_X_ERR_NOT_INIT;
+ }
+
+ if (dev->frame == MHU_V2_X_RECEIVER_FRAME) {
+ (RECV_FRAME(p_mhu))->rec_ch_window[channel].ch_msk_clr = mask;
+ return MHU_V_2_X_ERR_NONE;
+ } else {
+ return MHU_V_2_X_ERR_INVALID_ARG;
+ }
+}
+enum mhu_v2_x_error_t mhu_v2_x_initiate_transfer(
+ const struct mhu_v2_x_dev_t *dev)
+{
+ union mhu_v2_x_frame *p_mhu;
+
+ assert(dev != NULL);
+
+ p_mhu = (union mhu_v2_x_frame *)dev->base;
+
+ if (!(dev->is_initialized)) {
+ return MHU_V_2_X_ERR_NOT_INIT;
+ }
+
+ if (dev->frame != MHU_V2_X_SENDER_FRAME) {
+ return MHU_V_2_X_ERR_INVALID_ARG;
+ }
+
+ (SEND_FRAME(p_mhu))->access_request = ENABLE;
+
+ while (!((SEND_FRAME(p_mhu))->access_ready)) {
+ /* Wait in a loop for access ready signal to be high */
+ ;
+ }
+
+ return MHU_V_2_X_ERR_NONE;
+}
+
+enum mhu_v2_x_error_t mhu_v2_x_close_transfer(const struct mhu_v2_x_dev_t *dev)
+{
+ union mhu_v2_x_frame *p_mhu;
+
+ assert(dev != NULL);
+
+ p_mhu = (union mhu_v2_x_frame *)dev->base;
+
+ if (!(dev->is_initialized)) {
+ return MHU_V_2_X_ERR_NOT_INIT;
+ }
+
+ if (dev->frame != MHU_V2_X_SENDER_FRAME) {
+ return MHU_V_2_X_ERR_INVALID_ARG;
+ }
+
+ (SEND_FRAME(p_mhu))->access_request = DISABLE;
+
+ return MHU_V_2_X_ERR_NONE;
+}
diff --git a/drivers/arm/mhu/mhu_v2_x.h b/drivers/arm/mhu/mhu_v2_x.h
new file mode 100644
index 0000000..10247d2
--- /dev/null
+++ b/drivers/arm/mhu/mhu_v2_x.h
@@ -0,0 +1,210 @@
+/*
+ * Copyright (c) 2020-2022, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef MHU_V2_X_H
+#define MHU_V2_X_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#define MHU_2_X_INTR_NR2R_OFF (0x0u)
+#define MHU_2_X_INTR_R2NR_OFF (0x1u)
+#define MHU_2_1_INTR_CHCOMB_OFF (0x2u)
+
+#define MHU_2_X_INTR_NR2R_MASK (0x1u << MHU_2_X_INTR_NR2R_OFF)
+#define MHU_2_X_INTR_R2NR_MASK (0x1u << MHU_2_X_INTR_R2NR_OFF)
+#define MHU_2_1_INTR_CHCOMB_MASK (0x1u << MHU_2_1_INTR_CHCOMB_OFF)
+
+enum mhu_v2_x_frame_t {
+ MHU_V2_X_SENDER_FRAME = 0x0u,
+ MHU_V2_X_RECEIVER_FRAME = 0x1u,
+};
+
+enum mhu_v2_x_supported_revisions {
+ MHU_REV_READ_FROM_HW = 0,
+ MHU_REV_2_0,
+ MHU_REV_2_1,
+};
+
+struct mhu_v2_x_dev_t {
+ uintptr_t base;
+ enum mhu_v2_x_frame_t frame;
+ uint32_t subversion; /*!< Hardware subversion: v2.X */
+ bool is_initialized; /*!< Indicates if the MHU driver
+ * is initialized and enabled
+ */
+};
+
+/**
+ * MHU v2 error enumeration types.
+ */
+enum mhu_v2_x_error_t {
+ MHU_V_2_X_ERR_NONE = 0,
+ MHU_V_2_X_ERR_NOT_INIT = -1,
+ MHU_V_2_X_ERR_ALREADY_INIT = -2,
+ MHU_V_2_X_ERR_UNSUPPORTED_VERSION = -3,
+ MHU_V_2_X_ERR_INVALID_ARG = -4,
+ MHU_V_2_X_ERR_GENERAL = -5
+};
+
+/**
+ * Initializes the driver.
+ *
+ * dev MHU device struct mhu_v2_x_dev_t.
+ * rev MHU revision (if can't be identified from HW).
+ *
+ * Reads the MHU hardware version.
+ *
+ * Returns mhu_v2_x_error_t error code.
+ *
+ * MHU revision only has to be specified when versions can't be read
+ * from HW (ARCH_MAJOR_REV reg reads as 0x0).
+ *
+ * This function doesn't check if dev is NULL.
+ */
+enum mhu_v2_x_error_t mhu_v2_x_driver_init(struct mhu_v2_x_dev_t *dev,
+ enum mhu_v2_x_supported_revisions rev);
+
+/**
+ * Returns the number of channels implemented.
+ *
+ * dev MHU device struct mhu_v2_x_dev_t.
+ *
+ * This function doesn't check if dev is NULL.
+ */
+uint32_t mhu_v2_x_get_num_channel_implemented(
+ const struct mhu_v2_x_dev_t *dev);
+
+/**
+ * Sends the value over a channel.
+ *
+ * dev MHU device struct mhu_v2_x_dev_t.
+ * channel Channel to send the value over.
+ * val Value to send.
+ *
+ * Sends the value over a channel.
+ *
+ * Returns mhu_v2_x_error_t error code.
+ *
+ * This function doesn't check if dev is NULL.
+ * This function doesn't check if channel is implemented.
+ */
+enum mhu_v2_x_error_t mhu_v2_x_channel_send(const struct mhu_v2_x_dev_t *dev,
+ uint32_t channel, uint32_t val);
+
+/**
+ * Polls sender channel status.
+ *
+ * dev MHU device struct mhu_v2_x_dev_t.
+ * channel Channel to poll the status of.
+ * value Pointer to variable that will store the value.
+ *
+ * Polls sender channel status.
+ *
+ * Returns mhu_v2_x_error_t error code.
+ *
+ * This function doesn't check if dev is NULL.
+ * This function doesn't check if channel is implemented.
+ */
+enum mhu_v2_x_error_t mhu_v2_x_channel_poll(const struct mhu_v2_x_dev_t *dev,
+ uint32_t channel, uint32_t *value);
+
+/**
+ * Clears the channel after the value is send over it.
+ *
+ * dev MHU device struct mhu_v2_x_dev_t.
+ * channel Channel to clear.
+ *
+ * Clears the channel after the value is send over it.
+ *
+ * Returns mhu_v2_x_error_t error code..
+ *
+ * This function doesn't check if dev is NULL.
+ * This function doesn't check if channel is implemented.
+ */
+enum mhu_v2_x_error_t mhu_v2_x_channel_clear(const struct mhu_v2_x_dev_t *dev,
+ uint32_t channel);
+
+/**
+ * Receives the value over a channel.
+ *
+ * dev MHU device struct mhu_v2_x_dev_t.
+ * channel Channel to receive the value from.
+ * value Pointer to variable that will store the value.
+ *
+ * Receives the value over a channel.
+ *
+ * Returns mhu_v2_x_error_t error code.
+ *
+ * This function doesn't check if dev is NULL.
+ * This function doesn't check if channel is implemented.
+ */
+enum mhu_v2_x_error_t mhu_v2_x_channel_receive(
+ const struct mhu_v2_x_dev_t *dev, uint32_t channel, uint32_t *value);
+
+/**
+ * Sets bits in the Channel Mask.
+ *
+ * dev MHU device struct mhu_v2_x_dev_t.
+ * channel Which channel's mask to set.
+ * mask Mask to be set over a receiver frame.
+ *
+ * Sets bits in the Channel Mask.
+ *
+ * Returns mhu_v2_x_error_t error code..
+ *
+ * This function doesn't check if dev is NULL.
+ * This function doesn't check if channel is implemented.
+ */
+enum mhu_v2_x_error_t mhu_v2_x_channel_mask_set(
+ const struct mhu_v2_x_dev_t *dev, uint32_t channel, uint32_t mask);
+
+/**
+ * Clears bits in the Channel Mask.
+ *
+ * dev MHU device struct mhu_v2_x_dev_t.
+ * channel Which channel's mask to clear.
+ * mask Mask to be clear over a receiver frame.
+ *
+ * Clears bits in the Channel Mask.
+ *
+ * Returns mhu_v2_x_error_t error code.
+ *
+ * This function doesn't check if dev is NULL.
+ * This function doesn't check if channel is implemented.
+ */
+enum mhu_v2_x_error_t mhu_v2_x_channel_mask_clear(
+ const struct mhu_v2_x_dev_t *dev, uint32_t channel, uint32_t mask);
+
+/**
+ * Initiates a MHU transfer with the handshake signals.
+ *
+ * dev MHU device struct mhu_v2_x_dev_t.
+ *
+ * Initiates a MHU transfer with the handshake signals in a blocking mode.
+ *
+ * Returns mhu_v2_x_error_t error code.
+ *
+ * This function doesn't check if dev is NULL.
+ */
+enum mhu_v2_x_error_t mhu_v2_x_initiate_transfer(
+ const struct mhu_v2_x_dev_t *dev);
+
+/**
+ * Closes a MHU transfer with the handshake signals.
+ *
+ * dev MHU device struct mhu_v2_x_dev_t.
+ *
+ * Closes a MHU transfer with the handshake signals in a blocking mode.
+ *
+ * Returns mhu_v2_x_error_t error code.
+ *
+ * This function doesn't check if dev is NULL.
+ */
+enum mhu_v2_x_error_t mhu_v2_x_close_transfer(
+ const struct mhu_v2_x_dev_t *dev);
+
+#endif /* MHU_V2_X_H */
diff --git a/drivers/arm/mhu/mhu_wrapper_v2_x.c b/drivers/arm/mhu/mhu_wrapper_v2_x.c
new file mode 100644
index 0000000..d8b7cfd
--- /dev/null
+++ b/drivers/arm/mhu/mhu_wrapper_v2_x.c
@@ -0,0 +1,302 @@
+/*
+ * Copyright (c) 2022, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <drivers/arm/mhu.h>
+
+#include "mhu_v2_x.h"
+
+#define MHU_NOTIFY_VALUE (1234u)
+
+/*
+ * MHU devices for host:
+ * HSE: Host to Secure Enclave (sender device)
+ * SEH: Secure Enclave to Host (receiver device)
+ */
+struct mhu_v2_x_dev_t MHU1_HSE_DEV = {0, MHU_V2_X_SENDER_FRAME};
+struct mhu_v2_x_dev_t MHU1_SEH_DEV = {0, MHU_V2_X_RECEIVER_FRAME};
+
+static enum mhu_error_t error_mapping_to_mhu_error_t(enum mhu_v2_x_error_t err)
+{
+ switch (err) {
+ case MHU_V_2_X_ERR_NONE:
+ return MHU_ERR_NONE;
+ case MHU_V_2_X_ERR_NOT_INIT:
+ return MHU_ERR_NOT_INIT;
+ case MHU_V_2_X_ERR_ALREADY_INIT:
+ return MHU_ERR_ALREADY_INIT;
+ case MHU_V_2_X_ERR_UNSUPPORTED_VERSION:
+ return MHU_ERR_UNSUPPORTED_VERSION;
+ case MHU_V_2_X_ERR_INVALID_ARG:
+ return MHU_ERR_INVALID_ARG;
+ case MHU_V_2_X_ERR_GENERAL:
+ return MHU_ERR_GENERAL;
+ default:
+ return MHU_ERR_GENERAL;
+ }
+}
+
+static enum mhu_v2_x_error_t signal_and_wait_for_clear(void)
+{
+ enum mhu_v2_x_error_t err;
+ struct mhu_v2_x_dev_t *dev = &MHU1_HSE_DEV;
+ uint32_t val = MHU_NOTIFY_VALUE;
+ /* Using the last channel for notifications */
+ uint32_t channel_notify = mhu_v2_x_get_num_channel_implemented(dev) - 1;
+
+ err = mhu_v2_x_channel_send(dev, channel_notify, val);
+ if (err != MHU_V_2_X_ERR_NONE) {
+ return err;
+ }
+
+ do {
+ err = mhu_v2_x_channel_poll(dev, channel_notify, &val);
+ if (err != MHU_V_2_X_ERR_NONE) {
+ break;
+ }
+ } while (val != 0);
+
+ return err;
+}
+
+static enum mhu_v2_x_error_t wait_for_signal(void)
+{
+ enum mhu_v2_x_error_t err;
+ struct mhu_v2_x_dev_t *dev = &MHU1_SEH_DEV;
+ uint32_t val = 0;
+ /* Using the last channel for notifications */
+ uint32_t channel_notify = mhu_v2_x_get_num_channel_implemented(dev) - 1;
+
+ do {
+ err = mhu_v2_x_channel_receive(dev, channel_notify, &val);
+ if (err != MHU_V_2_X_ERR_NONE) {
+ break;
+ }
+ } while (val != MHU_NOTIFY_VALUE);
+
+ return err;
+}
+
+static enum mhu_v2_x_error_t clear_and_wait_for_next_signal(void)
+{
+ enum mhu_v2_x_error_t err;
+ struct mhu_v2_x_dev_t *dev = &MHU1_SEH_DEV;
+ uint32_t num_channels = mhu_v2_x_get_num_channel_implemented(dev);
+ uint32_t i;
+
+ /* Clear all channels */
+ for (i = 0; i < num_channels; ++i) {
+ err = mhu_v2_x_channel_clear(dev, i);
+ if (err != MHU_V_2_X_ERR_NONE) {
+ return err;
+ }
+ }
+
+ return wait_for_signal();
+}
+
+enum mhu_error_t mhu_init_sender(uintptr_t mhu_sender_base)
+{
+ enum mhu_v2_x_error_t err;
+
+ assert(mhu_sender_base != (uintptr_t)NULL);
+
+ MHU1_HSE_DEV.base = mhu_sender_base;
+
+ err = mhu_v2_x_driver_init(&MHU1_HSE_DEV, MHU_REV_READ_FROM_HW);
+ return error_mapping_to_mhu_error_t(err);
+}
+
+enum mhu_error_t mhu_init_receiver(uintptr_t mhu_receiver_base)
+{
+ enum mhu_v2_x_error_t err;
+ uint32_t num_channels, i;
+
+ assert(mhu_receiver_base != (uintptr_t)NULL);
+
+ MHU1_SEH_DEV.base = mhu_receiver_base;
+
+ err = mhu_v2_x_driver_init(&MHU1_SEH_DEV, MHU_REV_READ_FROM_HW);
+ if (err != MHU_V_2_X_ERR_NONE) {
+ return error_mapping_to_mhu_error_t(err);
+ }
+
+ num_channels = mhu_v2_x_get_num_channel_implemented(&MHU1_SEH_DEV);
+
+ /* Mask all channels except the notifying channel */
+ for (i = 0; i < (num_channels - 1); ++i) {
+ err = mhu_v2_x_channel_mask_set(&MHU1_SEH_DEV, i, UINT32_MAX);
+ if (err != MHU_V_2_X_ERR_NONE) {
+ return error_mapping_to_mhu_error_t(err);
+ }
+ }
+
+ /* The last channel is used for notifications */
+ err = mhu_v2_x_channel_mask_clear(
+ &MHU1_SEH_DEV, (num_channels - 1), UINT32_MAX);
+ return error_mapping_to_mhu_error_t(err);
+}
+
+/*
+ * Public function. See mhu.h
+ *
+ * The basic steps of transferring a message:
+ * 1. Initiate MHU transfer.
+ * 2. Send over the size of the payload on Channel 1. It is the very first
+ * 4 Bytes of the transfer. Continue with Channel 2.
+ * 3. Send over the payload, writing the channels one after the other
+ * (4 Bytes each). The last available channel is reserved for controlling
+ * the transfer.
+ * When the last channel is reached or no more data is left, STOP.
+ * 4. Notify the receiver using the last channel and wait for acknowledge.
+ * If there is still data to transfer, jump to step 3. Otherwise, proceed.
+ * 5. Close MHU transfer.
+ *
+ */
+enum mhu_error_t mhu_send_data(const uint8_t *send_buffer, size_t size)
+{
+ enum mhu_v2_x_error_t err;
+ struct mhu_v2_x_dev_t *dev = &MHU1_HSE_DEV;
+ uint32_t num_channels = mhu_v2_x_get_num_channel_implemented(dev);
+ uint32_t chan = 0;
+ uint32_t i;
+ uint32_t *p;
+
+ /* For simplicity, require the send_buffer to be 4-byte aligned */
+ if ((uintptr_t)send_buffer & 0x3U) {
+ return MHU_ERR_INVALID_ARG;
+ }
+
+ err = mhu_v2_x_initiate_transfer(dev);
+ if (err != MHU_V_2_X_ERR_NONE) {
+ return error_mapping_to_mhu_error_t(err);
+ }
+
+ /* First send over the size of the actual message */
+ err = mhu_v2_x_channel_send(dev, chan, (uint32_t)size);
+ if (err != MHU_V_2_X_ERR_NONE) {
+ return error_mapping_to_mhu_error_t(err);
+ }
+ chan++;
+
+ p = (uint32_t *)send_buffer;
+ for (i = 0; i < size; i += 4) {
+ err = mhu_v2_x_channel_send(dev, chan, *p++);
+ if (err != MHU_V_2_X_ERR_NONE) {
+ return error_mapping_to_mhu_error_t(err);
+ }
+ if (++chan == (num_channels - 1)) {
+ err = signal_and_wait_for_clear();
+ if (err != MHU_V_2_X_ERR_NONE) {
+ return error_mapping_to_mhu_error_t(err);
+ }
+ chan = 0;
+ }
+ }
+
+ /* Signal the end of transfer.
+ * It's not required to send a signal when the message was
+ * perfectly-aligned (num_channels - 1 channels were used in the last
+ * round) preventing it from signaling twice at the end of transfer.
+ */
+ if (chan != 0) {
+ err = signal_and_wait_for_clear();
+ if (err != MHU_V_2_X_ERR_NONE) {
+ return error_mapping_to_mhu_error_t(err);
+ }
+ }
+
+ err = mhu_v2_x_close_transfer(dev);
+ return error_mapping_to_mhu_error_t(err);
+}
+
+/*
+ * Public function. See mhu.h
+ *
+ * The basic steps of receiving a message:
+ * 1. Read the size of the payload from Channel 1. It is the very first
+ * 4 Bytes of the transfer. Continue with Channel 2.
+ * 2. Receive the payload, read the channels one after the other
+ * (4 Bytes each). The last available channel is reserved for controlling
+ * the transfer.
+ * When the last channel is reached clear all the channels
+ * (also sending an acknowledge on the last channel).
+ * 3. If there is still data to receive wait for a notification on the last
+ * channel and jump to step 2 as soon as it arrived. Otherwise, proceed.
+ * 4. End of transfer.
+ *
+ */
+enum mhu_error_t mhu_receive_data(uint8_t *receive_buffer, size_t *size)
+{
+ enum mhu_v2_x_error_t err;
+ struct mhu_v2_x_dev_t *dev = &MHU1_SEH_DEV;
+ uint32_t num_channels = mhu_v2_x_get_num_channel_implemented(dev);
+ uint32_t chan = 0;
+ uint32_t message_len;
+ uint32_t i;
+ uint32_t *p;
+
+ /* For simplicity, require:
+ * - the receive_buffer to be 4-byte aligned,
+ * - the buffer size to be a multiple of 4.
+ */
+ if (((uintptr_t)receive_buffer & 0x3U) || (*size & 0x3U)) {
+ return MHU_ERR_INVALID_ARG;
+ }
+
+ /* Busy wait for incoming reply */
+ err = wait_for_signal();
+ if (err != MHU_V_2_X_ERR_NONE) {
+ return error_mapping_to_mhu_error_t(err);
+ }
+
+ /* The first word is the length of the actual message */
+ err = mhu_v2_x_channel_receive(dev, chan, &message_len);
+ if (err != MHU_V_2_X_ERR_NONE) {
+ return error_mapping_to_mhu_error_t(err);
+ }
+ chan++;
+
+ if (message_len > *size) {
+ /* Message buffer too small */
+ *size = message_len;
+ return MHU_ERR_BUFFER_TOO_SMALL;
+ }
+
+ p = (uint32_t *)receive_buffer;
+ for (i = 0; i < message_len; i += 4) {
+ err = mhu_v2_x_channel_receive(dev, chan, p++);
+ if (err != MHU_V_2_X_ERR_NONE) {
+ return error_mapping_to_mhu_error_t(err);
+ }
+
+ /* Only wait for next transfer if there is still missing data */
+ if (++chan == (num_channels - 1) && (message_len - i) > 4) {
+ /* Busy wait for next transfer */
+ err = clear_and_wait_for_next_signal();
+ if (err != MHU_V_2_X_ERR_NONE) {
+ return error_mapping_to_mhu_error_t(err);
+ }
+ chan = 0;
+ }
+ }
+
+ /* Clear all channels */
+ for (i = 0; i < num_channels; ++i) {
+ err = mhu_v2_x_channel_clear(dev, i);
+ if (err != MHU_V_2_X_ERR_NONE) {
+ return error_mapping_to_mhu_error_t(err);
+ }
+ }
+
+ *size = message_len;
+
+ return MHU_ERR_NONE;
+}
diff --git a/include/drivers/arm/mhu.h b/include/drivers/arm/mhu.h
new file mode 100644
index 0000000..7745bd9
--- /dev/null
+++ b/include/drivers/arm/mhu.h
@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2022, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef MHU_H
+#define MHU_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+/**
+ * Generic MHU error enumeration types.
+ */
+enum mhu_error_t {
+ MHU_ERR_NONE = 0,
+ MHU_ERR_NOT_INIT = -1,
+ MHU_ERR_ALREADY_INIT = -2,
+ MHU_ERR_UNSUPPORTED_VERSION = -3,
+ MHU_ERR_UNSUPPORTED = -4,
+ MHU_ERR_INVALID_ARG = -5,
+ MHU_ERR_BUFFER_TOO_SMALL = -6,
+ MHU_ERR_GENERAL = -7,
+};
+
+/**
+ * Initializes sender MHU.
+ *
+ * mhu_sender_base Base address of sender MHU.
+ *
+ * Returns mhu_error_t error code.
+ *
+ * This function must be called before mhu_send_data().
+ */
+enum mhu_error_t mhu_init_sender(uintptr_t mhu_sender_base);
+
+
+/**
+ * Initializes receiver MHU.
+ *
+ * mhu_receiver_base Base address of receiver MHU.
+ *
+ * Returns mhu_error_t error code.
+ *
+ * This function must be called before mhu_receive_data().
+ */
+enum mhu_error_t mhu_init_receiver(uintptr_t mhu_receiver_base);
+
+/**
+ * Sends data over MHU.
+ *
+ * send_buffer Pointer to buffer containing the data to be transmitted.
+ * size Size of the data to be transmitted in bytes.
+ *
+ * Returns mhu_error_t error code.
+ *
+ * The send_buffer must be 4-byte aligned and its length must be at least
+ * (4 - (size % 4)) bytes bigger than the data size to prevent buffer
+ * over-reading.
+ */
+enum mhu_error_t mhu_send_data(const uint8_t *send_buffer, size_t size);
+
+/**
+ * Receives data from MHU.
+ *
+ * receive_buffer Pointer the buffer where to store the received data.
+ * size As input the size of the receive_buffer, as output the
+ * number of bytes received. As a limitation,
+ * the size of the buffer must be a multiple of 4.
+ *
+ * Returns mhu_error_t error code.
+ *
+ * The receive_buffer must be 4-byte aligned and its length must be a
+ * multiple of 4.
+ */
+enum mhu_error_t mhu_receive_data(uint8_t *receive_buffer, size_t *size);
+
+#endif /* MHU_H */