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/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 */