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 keystone family K2G SoC to communicate between various compute
processors with a central system controller entity.

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.

We introduce the basic registration and query capability for the
driver protocol as part of this change. Subsequent patches add in
functionality specific to the TI-SCI features.
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>

MAINTAINERS

@@ -11890,6 +11890,8 @@ M:	Santosh Shilimkar <ssantosh@kernel.org>
 L:	linux-arm-kernel@lists.infradead.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/arm/keystone/ti,sci.txt
+F:	drivers/firmware/ti_sci*
+F:	include/linux/soc/ti/ti_sci_protocol.h
 
 THANKO'S RAREMONO AM/FM/SW RADIO RECEIVER USB DRIVER
 M:	Hans Verkuil <hverkuil@xs4all.nl>

drivers/firmware/Kconfig

@@ -203,6 +203,21 @@ config QCOM_SCM_64
 	def_bool y
 	depends on QCOM_SCM && ARM64
 
+config TI_SCI_PROTOCOL
+	tristate "TI System Control Interface (TISCI) Message Protocol"
+	depends on TI_MESSAGE_MANAGER
+	help
+	  TI System Control Interface (TISCI) Message Protocol is used to manage
+	  compute systems such as ARM, DSP etc with the system controller in
+	  complex System on Chip(SoC) such as those found on certain keystone
+	  generation SoC from TI.
+
+	  System controller provides various facilities including power
+	  management function support.
+
+	  This protocol library is used by client drivers to use the features
+	  provided by the system controller.
+
 config HAVE_ARM_SMCCC
 	bool
 

drivers/firmware/Makefile

@@ -20,6 +20,7 @@ obj-$(CONFIG_QCOM_SCM)		+= qcom_scm.o
 obj-$(CONFIG_QCOM_SCM_64)	+= qcom_scm-64.o
 obj-$(CONFIG_QCOM_SCM_32)	+= qcom_scm-32.o
 CFLAGS_qcom_scm-32.o :=$(call as-instr,.arch armv7-a\n.arch_extension sec,-DREQUIRES_SEC=1) -march=armv7-a
+obj-$(CONFIG_TI_SCI_PROTOCOL)	+= ti_sci.o
 
 obj-y				+= broadcom/
 obj-y				+= meson/

drivers/firmware/ti_sci.h

+/*
+ * 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)  2015-2016 Texas Instruments Incorporated - http://www.ti.com/
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ *   Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the
+ *   distribution.
+ *
+ *   Neither the name of Texas Instruments Incorporated nor the names of
+ *   its contributors may be used to endorse or promote products derived
+ *   from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#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
+
+/**
+ * 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_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 */

include/linux/soc/ti/ti_sci_protocol.h

+/*
+ * Texas Instruments System Control Interface Protocol
+ *
+ * Copyright (C) 2015-2016 Texas Instruments Incorporated - http://www.ti.com/
+ *	Nishanth Menon
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __TISCI_PROTOCOL_H
+#define __TISCI_PROTOCOL_H
+
+/**
+ * struct ti_sci_version_info - version information structure
+ * @abi_major:	Major ABI version. Change here implies risk of backward
+ *		compatibility break.
+ * @abi_minor:	Minor ABI version. Change here implies new feature addition,
+ *		or compatible change in ABI.
+ * @firmware_revision:	Firmware revision (not usually used).
+ * @firmware_description: Firmware description (not usually used).
+ */
+struct ti_sci_version_info {
+	u8 abi_major;
+	u8 abi_minor;
+	u16 firmware_revision;
+	char firmware_description[32];
+};
+
+/**
+ * struct ti_sci_handle - Handle returned to TI SCI clients for usage.
+ * @version:	structure containing version information
+ */
+struct ti_sci_handle {
+	struct ti_sci_version_info version;
+};
+
+#if IS_ENABLED(CONFIG_TI_SCI_PROTOCOL)
+const struct ti_sci_handle *ti_sci_get_handle(struct device *dev);
+int ti_sci_put_handle(const struct ti_sci_handle *handle);
+const struct ti_sci_handle *devm_ti_sci_get_handle(struct device *dev);
+
+#else	/* CONFIG_TI_SCI_PROTOCOL */
+
+static inline const struct ti_sci_handle *ti_sci_get_handle(struct device *dev)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static inline int ti_sci_put_handle(const struct ti_sci_handle *handle)
+{
+	return -EINVAL;
+}
+
+static inline
+const struct ti_sci_handle *devm_ti_sci_get_handle(struct device *dev)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+#endif	/* CONFIG_TI_SCI_PROTOCOL */
+
+#endif	/* __TISCI_PROTOCOL_H */