lib/utils: Add RPMI messaging protocol and shared memory transport support

The RISC-V Platform Management Interface (RPMI) defines a messaging protocol
and shared memory based transport for bi-directional communication with an
on-chip or external microcontroller.

To support RPMI in OpenSBI, add:
1) The RPMI messaging protocol defines and helper macros
2) A FDT mailbox driver for the RPMI shared memory transport

Signed-off-by: Rahul Pathak <rpathak@ventanamicro.com>
Co-developed-by: Subrahmanya Lingappa <slingappa@ventanamicro.com>
Signed-off-by: Subrahmanya Lingappa <slingappa@ventanamicro.com>
Co-developed-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>

2 files changed, 287 insertions, 0 deletions

diff --git a/include/sbi_utils/mailbox/rpmi_mailbox.h b/include/sbi_utils/mailbox/rpmi_mailbox.h
new file mode 100644
index 00000000..61af51a8
--- /dev/null
+++ b/include/sbi_utils/mailbox/rpmi_mailbox.h
@@ -0,0 +1,32 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2023 Ventana Micro Systems Inc.
+ *
+ * Authors:
+ *   Anup Patel <apatel@ventanamicro.com>
+ */
+
+#ifndef __RPMI_MAILBOX_H__
+#define __RPMI_MAILBOX_H__
+
+#include <sbi/sbi_error.h>
+#include <sbi_utils/mailbox/rpmi_msgprot.h>
+
+#define rpmi_u32_count(__var)	(sizeof(__var) / sizeof(u32))
+
+/** Convert RPMI error to SBI error */
+int rpmi_xlate_error(enum rpmi_error error);
+
+/** Typical RPMI normal request with at least status code in response */
+int rpmi_normal_request_with_status(
+			struct mbox_chan *chan, u32 service_id,
+			void *req, u32 req_words, u32 req_endian_words,
+			void *resp, u32 resp_words, u32 resp_endian_words);
+
+/* RPMI posted request which is without any response*/
+int rpmi_posted_request(
+		struct mbox_chan *chan, u32 service_id,
+		void *req, u32 req_words, u32 req_endian_words);
+
+#endif /* !__RPMI_MAILBOX_H__ */
diff --git a/include/sbi_utils/mailbox/rpmi_msgprot.h b/include/sbi_utils/mailbox/rpmi_msgprot.h
new file mode 100644
index 00000000..f9f65447
--- /dev/null
+++ b/include/sbi_utils/mailbox/rpmi_msgprot.h
@@ -0,0 +1,255 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2023 Ventana Micro Systems Inc.
+ *
+ * Authors:
+ *   Rahul Pathak <rpathak@ventanamicro.com>
+ */
+
+#ifndef __RPMI_MSGPROT_H__
+#define __RPMI_MSGPROT_H__
+
+#include <sbi/sbi_byteorder.h>
+#include <sbi/sbi_error.h>
+
+/*
+ * 31                                            0
+ * +---------------------+-----------------------+
+ * | FLAGS | SERVICE_ID  |   SERVICEGROUP_ID     |
+ * +---------------------+-----------------------+
+ * |        TOKEN        |     DATA LENGTH       |
+ * +---------------------+-----------------------+
+ * |                 DATA/PAYLOAD                |
+ * +---------------------------------------------+
+ */
+
+/** Message Header byte offset */
+#define RPMI_MSG_HDR_OFFSET			(0x0)
+/** Message Header Size in bytes */
+#define RPMI_MSG_HDR_SIZE			(8)
+
+/** ServiceGroup ID field byte offset */
+#define RPMI_MSG_SERVICEGROUP_ID_OFFSET		(0x0)
+/** ServiceGroup ID field size in bytes */
+#define RPMI_MSG_SERVICEGROUP_ID_SIZE		(2)
+
+/** Service ID field byte offset */
+#define RPMI_MSG_SERVICE_ID_OFFSET		(0x2)
+/** Service ID field size in bytes */
+#define RPMI_MSG_SERVICE_ID_SIZE		(1)
+
+/** Flags field byte offset */
+#define RPMI_MSG_FLAGS_OFFSET			(0x3)
+/** Flags field size in bytes */
+#define RPMI_MSG_FLAGS_SIZE			(1)
+
+#define RPMI_MSG_FLAGS_TYPE_POS			(0U)
+#define RPMI_MSG_FLAGS_TYPE_MASK		0x7
+#define RPMI_MSG_FLAGS_TYPE			\
+	((0x7) << RPMI_MSG_FLAGS_TYPE_POS)
+
+#define RPMI_MSG_FLAGS_DOORBELL_POS		(3U)
+#define RPMI_MSG_FLAGS_DOORBELL_MASK		0x1
+#define RPMI_MSG_FLAGS_DOORBELL			\
+	((0x1) << RPMI_MSG_FLAGS_DOORBELL_POS)
+
+/** Data length field byte offset */
+#define RPMI_MSG_DATALEN_OFFSET			(0x4)
+/** Data length field size in bytes */
+#define RPMI_MSG_DATALEN_SIZE			(2)
+
+/** Token field byte offset */
+#define RPMI_MSG_TOKEN_OFFSET			(0x6)
+/** Token field size in bytes */
+#define RPMI_MSG_TOKEN_SIZE			(2)
+/** Token field mask */
+#define RPMI_MSG_TOKEN_MASK			(0xffffU)
+
+/** Data field byte offset */
+#define RPMI_MSG_DATA_OFFSET			(RPMI_MSG_HDR_SIZE)
+/** Data field size in bytes */
+#define RPMI_MSG_DATA_SIZE(__slot_size)		((__slot_size) - RPMI_MSG_HDR_SIZE)
+
+/** Minimum slot size in bytes */
+#define RPMI_SLOT_SIZE_MIN			(64)
+
+/** Name length of 16 characters */
+#define RPMI_NAME_CHARS_MAX			(16)
+
+/** Queue layout */
+#define RPMI_QUEUE_HEAD_SLOT		0
+#define RPMI_QUEUE_TAIL_SLOT		1
+#define RPMI_QUEUE_HEADER_SLOTS		2
+
+/** Default timeout values */
+#define RPMI_DEF_TX_TIMEOUT			20
+#define RPMI_DEF_RX_TIMEOUT			20
+
+/**
+ * Common macro to generate composite version from major
+ * and minor version numbers.
+ *
+ * RPMI has Specification version, Implementation version
+ * Service group versions which follow the same versioning
+ * encoding as below.
+ */
+#define RPMI_VERSION(__major, __minor) (((__major) << 16) | (__minor))
+
+/** RPMI Message Header */
+struct rpmi_message_header {
+	le16_t servicegroup_id;
+	uint8_t service_id;
+	uint8_t flags;
+	le16_t datalen;
+	le16_t token;
+} __packed;
+
+/** RPMI Message */
+struct rpmi_message {
+	struct rpmi_message_header header;
+	u8 data[0];
+} __packed;
+
+/** RPMI Messages Types */
+enum rpmi_message_type {
+	/* Normal request backed with ack */
+	RPMI_MSG_NORMAL_REQUEST = 0x0,
+	/* Request without any ack */
+	RPMI_MSG_POSTED_REQUEST = 0x1,
+	/* Acknowledgment for normal request message */
+	RPMI_MSG_ACKNOWLDGEMENT = 0x2,
+	/* Notification message */
+	RPMI_MSG_NOTIFICATION = 0x3,
+};
+
+/** RPMI Error Types */
+enum rpmi_error {
+	/* Success */
+	RPMI_SUCCESS		= 0,
+	/* General failure  */
+	RPMI_ERR_FAILED		= -1,
+	/* Service or feature not supported */
+	RPMI_ERR_NOTSUPP	= -2,
+	/* Invalid Parameter  */
+	RPMI_ERR_INVALID_PARAM    = -3,
+	/*
+	 * Denied to insufficient permissions
+	 * or due to unmet prerequisite
+	 */
+	RPMI_ERR_DENIED		= -4,
+	/* Invalid address or offset */
+	RPMI_ERR_INVALID_ADDR	= -5,
+	/*
+	 * Operation failed as it was already in
+	 * progress or the state has changed already
+	 * for which the operation was carried out.
+	 */
+	RPMI_ERR_ALREADY	= -6,
+	/*
+	 * Error in implementation which violates
+	 * the specification version
+	 */
+	RPMI_ERR_EXTENSION	= -7,
+	/* Operation failed due to hardware issues */
+	RPMI_ERR_HW_FAULT	= -8,
+	/* System, device or resource is busy */
+	RPMI_ERR_BUSY		= -9,
+	/* System or device or resource in invalid state */
+	RPMI_ERR_INVALID_STATE	= -10,
+	/* Index, offset or address is out of range */
+	RPMI_ERR_BAD_RANGE	= -11,
+	/* Operation timed out */
+	RPMI_ERR_TIMEOUT	= -12,
+	/*
+	 * Error in input or output or
+	 * error in sending or receiving data
+	 * through communication medium
+	 */
+	RPMI_ERR_IO		= -13,
+	/* No data available */
+	RPMI_ERR_NO_DATA	= -14,
+	RPMI_ERR_RESERVED_START	= -15,
+	RPMI_ERR_RESERVED_END	= -127,
+	RPMI_ERR_VENDOR_START	= -128,
+};
+
+/** RPMI Message Arguments */
+struct rpmi_message_args {
+	u32 flags;
+#define RPMI_MSG_FLAGS_NO_TX		(1U << 0)
+#define RPMI_MSG_FLAGS_NO_RX		(1U << 1)
+#define RPMI_MSG_FLAGS_NO_RX_TOKEN	(1U << 2)
+	enum rpmi_message_type type;
+	u8 service_id;
+	u32 tx_endian_words;
+	u32 rx_endian_words;
+	u16 rx_token;
+	u32 rx_data_len;
+};
+
+/*
+ * RPMI SERVICEGROUPS AND SERVICES
+ */
+
+/** RPMI ServiceGroups IDs */
+enum rpmi_servicegroup_id {
+	RPMI_SRVGRP_ID_MIN = 0,
+	RPMI_SRVGRP_BASE = 0x0001,
+	RPMI_SRVGRP_ID_MAX_COUNT,
+
+	/* Reserved range for service groups */
+	RPMI_SRVGRP_RESERVE_START = RPMI_SRVGRP_ID_MAX_COUNT,
+	RPMI_SRVGRP_RESERVE_END = 0x7FFF,
+
+	/* Vendor/Implementation-specific service groups range */
+	RPMI_SRVGRP_VENDOR_START = 0x8000,
+	RPMI_SRVGRP_VENDOR_END = 0xFFFF,
+};
+
+/** RPMI enable notification request */
+struct rpmi_enable_notification_req {
+	u32 eventid;
+};
+
+/** RPMI enable notification response */
+struct rpmi_enable_notification_resp {
+	s32 status;
+};
+
+/** RPMI Base ServiceGroup Service IDs */
+enum rpmi_base_service_id {
+	RPMI_BASE_SRV_ENABLE_NOTIFICATION = 0x01,
+	RPMI_BASE_SRV_GET_IMPLEMENTATION_VERSION = 0x02,
+	RPMI_BASE_SRV_GET_IMPLEMENTATION_IDN = 0x03,
+	RPMI_BASE_SRV_GET_SPEC_VERSION = 0x04,
+	RPMI_BASE_SRV_GET_PLATFORM_INFO = 0x05,
+	RPMI_BASE_SRV_PROBE_SERVICE_GROUP = 0x06,
+	RPMI_BASE_SRV_GET_ATTRIBUTES = 0x07,
+	RPMI_BASE_SRV_SET_MSI = 0x08,
+};
+
+#define RPMI_BASE_FLAGS_F0_PRIVILEGE		(1U << 2)
+#define RPMI_BASE_FLAGS_F0_EV_NOTIFY		(1U << 1)
+#define RPMI_BASE_FLAGS_F0_MSI_EN		(1U)
+
+enum rpmi_base_context_priv_level {
+	RPMI_BASE_CONTEXT_PRIV_S_MODE,
+	RPMI_BASE_CONTEXT_PRIV_M_MODE,
+};
+
+struct rpmi_base_get_attributes_resp {
+	s32 status_code;
+	u32 f0;
+	u32 f1;
+	u32 f2;
+	u32 f3;
+};
+
+struct rpmi_base_get_platform_info_resp {
+	s32 status;
+	u32 plat_info_len;
+	char plat_info[];
+};
+
+#endif /* !__RPMI_MSGPROT_H__ */