firmware: Add basic support for TI System Control Interface (TI SCI) protocol

Texas Instrument's System Control Interface (TI SCI) message protocol is
used in Texas Instrument's System on Chip (SoC) such as those in the K3
family AM654 SoC to communicate between various compute processors with
a central system controller entity.

The TI SCI message protocol provides support for management of various
hardware entities within the SoC. Add support driver to allow
communication with system controller entity within the SoC using the
mailbox client.

This is mostly derived from the TI SCI driver in Linux located at
drivers/firmware/ti_sci.c.

Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>

1 files changed, 80 insertions, 0 deletions

diff --git a/drivers/firmware/ti_sci.h b/drivers/firmware/ti_sci.h
new file mode 100644
index 0000000000..ae8506261d
--- /dev/null
+++ b/drivers/firmware/ti_sci.h
@@ -0,0 +1,80 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/*
+ * Texas Instruments System Control Interface (TISCI) Protocol
+ *
+ * Communication protocol with TI SCI hardware
+ * The system works in a message response protocol
+ * See: http://processors.wiki.ti.com/index.php/TISCI for details
+ *
+ * Copyright (C)  2018 Texas Instruments Incorporated - http://www.ti.com/
+ * Based on drivers/firmware/ti_sci.h from Linux.
+ *
+ */
+
+#ifndef __TI_SCI_H
+#define __TI_SCI_H
+
+/* Generic Messages */
+#define TI_SCI_MSG_ENABLE_WDT		0x0000
+#define TI_SCI_MSG_WAKE_RESET		0x0001
+#define TI_SCI_MSG_VERSION		0x0002
+#define TI_SCI_MSG_WAKE_REASON		0x0003
+#define TI_SCI_MSG_GOODBYE		0x0004
+#define TI_SCI_MSG_SYS_RESET		0x0005
+#define TI_SCI_MSG_BOARD_CONFIG		0x000b
+
+/**
+ * struct ti_sci_msg_hdr - Generic Message Header for All messages and responses
+ * @type:	Type of messages: One of TI_SCI_MSG* values
+ * @host:	Host of the message
+ * @seq:	Message identifier indicating a transfer sequence
+ * @flags:	Flag for the message
+ */
+struct ti_sci_msg_hdr {
+	u16 type;
+	u8 host;
+	u8 seq;
+#define TI_SCI_MSG_FLAG(val)			(1 << (val))
+#define TI_SCI_FLAG_REQ_GENERIC_NORESPONSE	0x0
+#define TI_SCI_FLAG_REQ_ACK_ON_RECEIVED		TI_SCI_MSG_FLAG(0)
+#define TI_SCI_FLAG_REQ_ACK_ON_PROCESSED	TI_SCI_MSG_FLAG(1)
+#define TI_SCI_FLAG_RESP_GENERIC_NACK		0x0
+#define TI_SCI_FLAG_RESP_GENERIC_ACK		TI_SCI_MSG_FLAG(1)
+	/* Additional Flags */
+	u32 flags;
+} __packed;
+
+/**
+ * struct ti_sci_secure_msg_hdr - Header that prefixes all TISCI messages sent
+ *				  via secure transport.
+ * @checksum:	crc16 checksum for the entire message
+ * @reserved:	Reserved for future use.
+ */
+struct ti_sci_secure_msg_hdr {
+	u16 checksum;
+	u16 reserved;
+} __packed;
+
+/**
+ * struct ti_sci_msg_resp_version - Response for a message
+ * @hdr:		Generic header
+ * @firmware_description: String describing the firmware
+ * @firmware_revision:	Firmware revision
+ * @abi_major:		Major version of the ABI that firmware supports
+ * @abi_minor:		Minor version of the ABI that firmware supports
+ *
+ * In general, ABI version changes follow the rule that minor version increments
+ * are backward compatible. Major revision changes in ABI may not be
+ * backward compatible.
+ *
+ * Response to a generic message with message type TI_SCI_MSG_VERSION
+ */
+struct ti_sci_msg_resp_version {
+	struct ti_sci_msg_hdr hdr;
+	char firmware_description[32];
+	u16 firmware_revision;
+	u8 abi_major;
+	u8 abi_minor;
+} __packed;
+
+#endif /* __TI_SCI_H */