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>

4 files changed, 542 insertions, 0 deletions

diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index 4c32426e0e..cb73b70f5b 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -4,3 +4,16 @@ config FIRMWARE
 config ARM_PSCI_FW
 	bool
 	select FIRMWARE
+
+config TI_SCI_PROTOCOL
+	tristate "TI System Control Interface (TISCI) Message Protocol"
+	depends on K3_SEC_PROXY
+	select FIRMWARE
+	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 K3
+	  generation SoC from TI.
+
+	  This protocol library is used by client drivers to use the features
+	  provided by the system controller.
diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
index b208255368..1cdda14977 100644
--- a/drivers/firmware/Makefile
+++ b/drivers/firmware/Makefile
@@ -1,2 +1,3 @@
 obj-$(CONFIG_FIRMWARE)		+= firmware-uclass.o
 obj-$(CONFIG_ARM_PSCI_FW)	+= psci.o
+obj-$(CONFIG_TI_SCI_PROTOCOL)	+= ti_sci.o
diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
new file mode 100644
index 0000000000..857d960787
--- /dev/null
+++ b/drivers/firmware/ti_sci.c
@@ -0,0 +1,448 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Texas Instruments System Control Interface Protocol Driver
+ * Based on drivers/firmware/ti_sci.c from Linux.
+ *
+ * Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
+ *	Lokesh Vutla <lokeshvutla@ti.com>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <mailbox.h>
+#include <dm/device.h>
+#include <linux/err.h>
+#include <linux/soc/ti/k3-sec-proxy.h>
+#include <linux/soc/ti/ti_sci_protocol.h>
+
+#include "ti_sci.h"
+
+/* List of all TI SCI devices active in system */
+static LIST_HEAD(ti_sci_list);
+
+/**
+ * struct ti_sci_xfer - Structure representing a message flow
+ * @tx_message:	Transmit message
+ * @rx_len:	Receive message length
+ */
+struct ti_sci_xfer {
+	struct k3_sec_proxy_msg tx_message;
+	u8 rx_len;
+};
+
+/**
+ * struct ti_sci_desc - Description of SoC integration
+ * @host_id:		Host identifier representing the compute entity
+ * @max_rx_timeout_us:	Timeout for communication with SoC (in Microseconds)
+ * @max_msg_size:	Maximum size of data per message that can be handled.
+ */
+struct ti_sci_desc {
+	u8 host_id;
+	int max_rx_timeout_us;
+	int max_msg_size;
+};
+
+/**
+ * struct ti_sci_info - Structure representing a TI SCI instance
+ * @dev:	Device pointer
+ * @desc:	SoC description for this instance
+ * @handle:	Instance of TI SCI handle to send to clients.
+ * @chan_tx:	Transmit mailbox channel
+ * @chan_rx:	Receive mailbox channel
+ * @xfer:	xfer info
+ * @list:	list head
+ * @is_secure:	Determines if the communication is through secure threads.
+ * @host_id:	Host identifier representing the compute entity
+ * @seq:	Seq id used for verification for tx and rx message.
+ */
+struct ti_sci_info {
+	struct udevice *dev;
+	const struct ti_sci_desc *desc;
+	struct ti_sci_handle handle;
+	struct mbox_chan chan_tx;
+	struct mbox_chan chan_rx;
+	struct mbox_chan chan_notify;
+	struct ti_sci_xfer xfer;
+	struct list_head list;
+	bool is_secure;
+	u8 host_id;
+	u8 seq;
+};
+
+#define handle_to_ti_sci_info(h) container_of(h, struct ti_sci_info, handle)
+
+/**
+ * ti_sci_setup_one_xfer() - Setup one message type
+ * @info:	Pointer to SCI entity information
+ * @msg_type:	Message type
+ * @msg_flags:	Flag to set for the message
+ * @buf:	Buffer to be send to mailbox channel
+ * @tx_message_size: transmit message size
+ * @rx_message_size: receive message size
+ *
+ * Helper function which is used by various command functions that are
+ * exposed to clients of this driver for allocating a message traffic event.
+ *
+ * Return: Corresponding ti_sci_xfer pointer if all went fine,
+ *	   else appropriate error pointer.
+ */
+static struct ti_sci_xfer *ti_sci_setup_one_xfer(struct ti_sci_info *info,
+						 u16 msg_type, u32 msg_flags,
+						 u32 *buf,
+						 size_t tx_message_size,
+						 size_t rx_message_size)
+{
+	struct ti_sci_xfer *xfer = &info->xfer;
+	struct ti_sci_msg_hdr *hdr;
+
+	/* Ensure we have sane transfer sizes */
+	if (rx_message_size > info->desc->max_msg_size ||
+	    tx_message_size > info->desc->max_msg_size ||
+	    rx_message_size < sizeof(*hdr) || tx_message_size < sizeof(*hdr))
+		return ERR_PTR(-ERANGE);
+
+	info->seq = ~info->seq;
+	xfer->tx_message.buf = buf;
+	xfer->tx_message.len = tx_message_size;
+	xfer->rx_len = (u8)rx_message_size;
+
+	hdr = (struct ti_sci_msg_hdr *)buf;
+	hdr->seq = info->seq;
+	hdr->type = msg_type;
+	hdr->host = info->host_id;
+	hdr->flags = msg_flags;
+
+	return xfer;
+}
+
+/**
+ * ti_sci_get_response() - Receive response from mailbox channel
+ * @info:	Pointer to SCI entity information
+ * @xfer:	Transfer to initiate and wait for response
+ * @chan:	Channel to receive the response
+ *
+ * Return: -ETIMEDOUT in case of no response, if transmit error,
+ *	   return corresponding error, else if all goes well,
+ *	   return 0.
+ */
+static inline int ti_sci_get_response(struct ti_sci_info *info,
+				      struct ti_sci_xfer *xfer,
+				      struct mbox_chan *chan)
+{
+	struct k3_sec_proxy_msg *msg = &xfer->tx_message;
+	struct ti_sci_secure_msg_hdr *secure_hdr;
+	struct ti_sci_msg_hdr *hdr;
+	int ret;
+
+	/* Receive the response */
+	ret = mbox_recv(chan, msg, info->desc->max_rx_timeout_us);
+	if (ret) {
+		dev_err(info->dev, "%s: Message receive failed. ret = %d\n",
+			__func__, ret);
+		return ret;
+	}
+
+	/* ToDo: Verify checksum */
+	if (info->is_secure) {
+		secure_hdr = (struct ti_sci_secure_msg_hdr *)msg->buf;
+		msg->buf = (u32 *)((void *)msg->buf + sizeof(*secure_hdr));
+	}
+
+	/* msg is updated by mailbox driver */
+	hdr = (struct ti_sci_msg_hdr *)msg->buf;
+
+	/* Sanity check for message response */
+	if (hdr->seq != info->seq) {
+		dev_dbg(info->dev, "%s: Message for %d is not expected\n",
+			__func__, hdr->seq);
+		return ret;
+	}
+
+	if (msg->len > info->desc->max_msg_size) {
+		dev_err(info->dev, "%s: Unable to handle %zu xfer (max %d)\n",
+			__func__, msg->len, info->desc->max_msg_size);
+		return -EINVAL;
+	}
+
+	if (msg->len < xfer->rx_len) {
+		dev_err(info->dev, "%s: Recv xfer %zu < expected %d length\n",
+			__func__, msg->len, xfer->rx_len);
+	}
+
+	return ret;
+}
+
+/**
+ * ti_sci_do_xfer() - Do one transfer
+ * @info:	Pointer to SCI entity information
+ * @xfer:	Transfer to initiate and wait for response
+ *
+ * Return: 0 if all went fine, else return appropriate error.
+ */
+static inline int ti_sci_do_xfer(struct ti_sci_info *info,
+				 struct ti_sci_xfer *xfer)
+{
+	struct k3_sec_proxy_msg *msg = &xfer->tx_message;
+	u8 secure_buf[info->desc->max_msg_size];
+	struct ti_sci_secure_msg_hdr secure_hdr;
+	int ret;
+
+	if (info->is_secure) {
+		/* ToDo: get checksum of the entire message */
+		secure_hdr.checksum = 0;
+		secure_hdr.reserved = 0;
+		memcpy(&secure_buf[sizeof(secure_hdr)], xfer->tx_message.buf,
+		       xfer->tx_message.len);
+
+		xfer->tx_message.buf = (u32 *)secure_buf;
+		xfer->tx_message.len += sizeof(secure_hdr);
+		xfer->rx_len += sizeof(secure_hdr);
+	}
+
+	/* Send the message */
+	ret = mbox_send(&info->chan_tx, msg);
+	if (ret) {
+		dev_err(info->dev, "%s: Message sending failed. ret = %d\n",
+			__func__, ret);
+		return ret;
+	}
+
+	return ti_sci_get_response(info, xfer, &info->chan_rx);
+}
+
+/**
+ * ti_sci_cmd_get_revision() - command to get the revision of the SCI entity
+ * @handle:	pointer to TI SCI handle
+ *
+ * Updates the SCI information in the internal data structure.
+ *
+ * Return: 0 if all went fine, else return appropriate error.
+ */
+static int ti_sci_cmd_get_revision(struct ti_sci_handle *handle)
+{
+	struct ti_sci_msg_resp_version *rev_info;
+	struct ti_sci_version_info *ver;
+	struct ti_sci_msg_hdr hdr;
+	struct ti_sci_info *info;
+	struct ti_sci_xfer *xfer;
+	int ret;
+
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	if (!handle)
+		return -EINVAL;
+
+	info = handle_to_ti_sci_info(handle);
+
+	xfer = ti_sci_setup_one_xfer(info, TI_SCI_MSG_VERSION, 0x0,
+				     (u32 *)&hdr, sizeof(struct ti_sci_msg_hdr),
+				     sizeof(*rev_info));
+	if (IS_ERR(xfer)) {
+		ret = PTR_ERR(xfer);
+		dev_err(info->dev, "Message alloc failed(%d)\n", ret);
+		return ret;
+	}
+
+	ret = ti_sci_do_xfer(info, xfer);
+	if (ret) {
+		dev_err(info->dev, "Mbox communication fail %d\n", ret);
+		return ret;
+	}
+
+	rev_info = (struct ti_sci_msg_resp_version *)xfer->tx_message.buf;
+
+	ver = &handle->version;
+	ver->abi_major = rev_info->abi_major;
+	ver->abi_minor = rev_info->abi_minor;
+	ver->firmware_revision = rev_info->firmware_revision;
+	strncpy(ver->firmware_description, rev_info->firmware_description,
+		sizeof(ver->firmware_description));
+
+	return 0;
+}
+
+/**
+ * ti_sci_is_response_ack() - Generic ACK/NACK message checkup
+ * @r:	pointer to response buffer
+ *
+ * Return: true if the response was an ACK, else returns false.
+ */
+static inline bool ti_sci_is_response_ack(void *r)
+{
+	struct ti_sci_msg_hdr *hdr = r;
+
+	return hdr->flags & TI_SCI_FLAG_RESP_GENERIC_ACK ? true : false;
+}
+
+/**
+ * ti_sci_get_handle_from_sysfw() - Get the TI SCI handle of the SYSFW
+ * @dev:	Pointer to the SYSFW device
+ *
+ * Return: pointer to handle if successful, else EINVAL if invalid conditions
+ *         are encountered.
+ */
+const
+struct ti_sci_handle *ti_sci_get_handle_from_sysfw(struct udevice *sci_dev)
+{
+	if (!sci_dev)
+		return ERR_PTR(-EINVAL);
+
+	struct ti_sci_info *info = dev_get_priv(sci_dev);
+
+	if (!info)
+		return ERR_PTR(-EINVAL);
+
+	struct ti_sci_handle *handle = &info->handle;
+
+	if (!handle)
+		return ERR_PTR(-EINVAL);
+
+	return handle;
+}
+
+/**
+ * ti_sci_get_handle() - Get the TI SCI handle for a device
+ * @dev:	Pointer to device for which we want SCI handle
+ *
+ * Return: pointer to handle if successful, else EINVAL if invalid conditions
+ *         are encountered.
+ */
+const struct ti_sci_handle *ti_sci_get_handle(struct udevice *dev)
+{
+	if (!dev)
+		return ERR_PTR(-EINVAL);
+
+	struct udevice *sci_dev = dev_get_parent(dev);
+
+	return ti_sci_get_handle_from_sysfw(sci_dev);
+}
+
+/**
+ * ti_sci_get_by_phandle() - Get the TI SCI handle using DT phandle
+ * @dev:	device node
+ * @propname:	property name containing phandle on TISCI node
+ *
+ * Return: pointer to handle if successful, else appropriate error value.
+ */
+const struct ti_sci_handle *ti_sci_get_by_phandle(struct udevice *dev,
+						  const char *property)
+{
+	struct ti_sci_info *entry, *info = NULL;
+	u32 phandle, err;
+	ofnode node;
+
+	err = ofnode_read_u32(dev_ofnode(dev), property, &phandle);
+	if (err)
+		return ERR_PTR(err);
+
+	node = ofnode_get_by_phandle(phandle);
+	if (!ofnode_valid(node))
+		return ERR_PTR(-EINVAL);
+
+	list_for_each_entry(entry, &ti_sci_list, list)
+		if (ofnode_equal(dev_ofnode(entry->dev), node)) {
+			info = entry;
+			break;
+		}
+
+	if (!info)
+		return ERR_PTR(-ENODEV);
+
+	return &info->handle;
+}
+
+/**
+ * ti_sci_of_to_info() - generate private data from device tree
+ * @dev:	corresponding system controller interface device
+ * @info:	pointer to driver specific private data
+ *
+ * Return: 0 if all goes good, else appropriate error message.
+ */
+static int ti_sci_of_to_info(struct udevice *dev, struct ti_sci_info *info)
+{
+	int ret;
+
+	ret = mbox_get_by_name(dev, "tx", &info->chan_tx);
+	if (ret) {
+		dev_err(dev, "%s: Acquiring Tx channel failed. ret = %d\n",
+			__func__, ret);
+		return ret;
+	}
+
+	ret = mbox_get_by_name(dev, "rx", &info->chan_rx);
+	if (ret) {
+		dev_err(dev, "%s: Acquiring Rx channel failed. ret = %d\n",
+			__func__, ret);
+		return ret;
+	}
+
+	/* Notify channel is optional. Enable only if populated */
+	ret = mbox_get_by_name(dev, "notify", &info->chan_notify);
+	if (ret) {
+		dev_dbg(dev, "%s: Acquiring notify channel failed. ret = %d\n",
+			__func__, ret);
+	}
+
+	info->host_id = dev_read_u32_default(dev, "ti,host-id",
+					     info->desc->host_id);
+
+	info->is_secure = dev_read_bool(dev, "ti,secure-host");
+
+	return 0;
+}
+
+/**
+ * ti_sci_probe() - Basic probe
+ * @dev:	corresponding system controller interface device
+ *
+ * Return: 0 if all goes good, else appropriate error message.
+ */
+static int ti_sci_probe(struct udevice *dev)
+{
+	struct ti_sci_info *info;
+	int ret;
+
+	debug("%s(dev=%p)\n", __func__, dev);
+
+	info = dev_get_priv(dev);
+	info->desc = (void *)dev_get_driver_data(dev);
+
+	ret = ti_sci_of_to_info(dev, info);
+	if (ret) {
+		dev_err(dev, "%s: Probe failed with error %d\n", __func__, ret);
+		return ret;
+	}
+
+	info->dev = dev;
+	info->seq = 0xA;
+
+	list_add_tail(&info->list, &ti_sci_list);
+
+	ret = ti_sci_cmd_get_revision(&info->handle);
+
+	return ret;
+}
+
+/* Description for AM654 */
+static const struct ti_sci_desc ti_sci_sysfw_am654_desc = {
+	.host_id = 4,
+	.max_rx_timeout_us = 1000000,
+	.max_msg_size = 60,
+};
+
+static const struct udevice_id ti_sci_ids[] = {
+	{
+		.compatible = "ti,k2g-sci",
+		.data = (ulong)&ti_sci_sysfw_am654_desc
+	},
+	{ /* Sentinel */ },
+};
+
+U_BOOT_DRIVER(ti_sci) = {
+	.name = "ti_sci",
+	.id = UCLASS_FIRMWARE,
+	.of_match = ti_sci_ids,
+	.probe = ti_sci_probe,
+	.priv_auto_alloc_size = sizeof(struct ti_sci_info),
+};
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 */