1 files changed, 632 insertions, 0 deletions
diff --git a/drivers/firmware/arm_scmi/transports/optee.c b/drivers/firmware/arm_scmi/transports/optee.c
new file mode 100644
index 000000000000..56fc63edf51e
--- /dev/null
+++ b/drivers/firmware/arm_scmi/transports/optee.c
@@ -0,0 +1,632 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019-2021 Linaro Ltd.
+ */
+
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/tee_drv.h>
+#include <linux/uuid.h>
+#include <uapi/linux/tee.h>
+
+#include "../common.h"
+
+#define SCMI_OPTEE_MAX_MSG_SIZE		128
+
+enum scmi_optee_pta_cmd {
+	/*
+	 * PTA_SCMI_CMD_CAPABILITIES - Get channel capabilities
+	 *
+	 * [out]    value[0].a: Capability bit mask (enum pta_scmi_caps)
+	 * [out]    value[0].b: Extended capabilities or 0
+	 */
+	PTA_SCMI_CMD_CAPABILITIES = 0,
+
+	/*
+	 * PTA_SCMI_CMD_PROCESS_SMT_CHANNEL - Process SCMI message in SMT buffer
+	 *
+	 * [in]     value[0].a: Channel handle
+	 *
+	 * Shared memory used for SCMI message/response exhange is expected
+	 * already identified and bound to channel handle in both SCMI agent
+	 * and SCMI server (OP-TEE) parts.
+	 * The memory uses SMT header to carry SCMI meta-data (protocol ID and
+	 * protocol message ID).
+	 */
+	PTA_SCMI_CMD_PROCESS_SMT_CHANNEL = 1,
+
+	/*
+	 * PTA_SCMI_CMD_PROCESS_SMT_CHANNEL_MESSAGE - Process SMT/SCMI message
+	 *
+	 * [in]     value[0].a: Channel handle
+	 * [in/out] memref[1]: Message/response buffer (SMT and SCMI payload)
+	 *
+	 * Shared memory used for SCMI message/response is a SMT buffer
+	 * referenced by param[1]. It shall be 128 bytes large to fit response
+	 * payload whatever message playload size.
+	 * The memory uses SMT header to carry SCMI meta-data (protocol ID and
+	 * protocol message ID).
+	 */
+	PTA_SCMI_CMD_PROCESS_SMT_CHANNEL_MESSAGE = 2,
+
+	/*
+	 * PTA_SCMI_CMD_GET_CHANNEL - Get channel handle
+	 *
+	 * SCMI shm information are 0 if agent expects to use OP-TEE regular SHM
+	 *
+	 * [in]     value[0].a: Channel identifier
+	 * [out]    value[0].a: Returned channel handle
+	 * [in]     value[0].b: Requested capabilities mask (enum pta_scmi_caps)
+	 */
+	PTA_SCMI_CMD_GET_CHANNEL = 3,
+
+	/*
+	 * PTA_SCMI_CMD_PROCESS_MSG_CHANNEL - Process SCMI message in a MSG
+	 * buffer pointed by memref parameters
+	 *
+	 * [in]     value[0].a: Channel handle
+	 * [in]     memref[1]: Message buffer (MSG and SCMI payload)
+	 * [out]    memref[2]: Response buffer (MSG and SCMI payload)
+	 *
+	 * Shared memories used for SCMI message/response are MSG buffers
+	 * referenced by param[1] and param[2]. MSG transport protocol
+	 * uses a 32bit header to carry SCMI meta-data (protocol ID and
+	 * protocol message ID) followed by the effective SCMI message
+	 * payload.
+	 */
+	PTA_SCMI_CMD_PROCESS_MSG_CHANNEL = 4,
+};
+
+/*
+ * OP-TEE SCMI service capabilities bit flags (32bit)
+ *
+ * PTA_SCMI_CAPS_SMT_HEADER
+ * When set, OP-TEE supports command using SMT header protocol (SCMI shmem) in
+ * shared memory buffers to carry SCMI protocol synchronisation information.
+ *
+ * PTA_SCMI_CAPS_MSG_HEADER
+ * When set, OP-TEE supports command using MSG header protocol in an OP-TEE
+ * shared memory to carry SCMI protocol synchronisation information and SCMI
+ * message payload.
+ */
+#define PTA_SCMI_CAPS_NONE		0
+#define PTA_SCMI_CAPS_SMT_HEADER	BIT(0)
+#define PTA_SCMI_CAPS_MSG_HEADER	BIT(1)
+#define PTA_SCMI_CAPS_MASK		(PTA_SCMI_CAPS_SMT_HEADER | \
+					 PTA_SCMI_CAPS_MSG_HEADER)
+
+/**
+ * struct scmi_optee_channel - Description of an OP-TEE SCMI channel
+ *
+ * @channel_id: OP-TEE channel ID used for this transport
+ * @tee_session: TEE session identifier
+ * @caps: OP-TEE SCMI channel capabilities
+ * @rx_len: Response size
+ * @mu: Mutex protection on channel access
+ * @cinfo: SCMI channel information
+ * @req: union for SCMI interface
+ * @req.shmem: Virtual base address of the shared memory
+ * @req.msg: Shared memory protocol handle for SCMI request and
+ *   synchronous response
+ * @tee_shm: TEE shared memory handle @req or NULL if using IOMEM shmem
+ * @link: Reference in agent's channel list
+ */
+struct scmi_optee_channel {
+	u32 channel_id;
+	u32 tee_session;
+	u32 caps;
+	u32 rx_len;
+	struct mutex mu;
+	struct scmi_chan_info *cinfo;
+	union {
+		struct scmi_shared_mem __iomem *shmem;
+		struct scmi_msg_payld *msg;
+	} req;
+	struct tee_shm *tee_shm;
+	struct list_head link;
+};
+
+/**
+ * struct scmi_optee_agent - OP-TEE transport private data
+ *
+ * @dev: Device used for communication with TEE
+ * @tee_ctx: TEE context used for communication
+ * @caps: Supported channel capabilities
+ * @mu: Mutex for protection of @channel_list
+ * @channel_list: List of all created channels for the agent
+ */
+struct scmi_optee_agent {
+	struct device *dev;
+	struct tee_context *tee_ctx;
+	u32 caps;
+	struct mutex mu;
+	struct list_head channel_list;
+};
+
+static struct scmi_transport_core_operations *core;
+
+/* There can be only 1 SCMI service in OP-TEE we connect to */
+static struct scmi_optee_agent *scmi_optee_private;
+
+/* Open a session toward SCMI OP-TEE service with REE_KERNEL identity */
+static int open_session(struct scmi_optee_agent *agent, u32 *tee_session)
+{
+	struct device *dev = agent->dev;
+	struct tee_client_device *scmi_pta = to_tee_client_device(dev);
+	struct tee_ioctl_open_session_arg arg = { };
+	int ret;
+
+	memcpy(arg.uuid, scmi_pta->id.uuid.b, TEE_IOCTL_UUID_LEN);
+	arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL;
+
+	ret = tee_client_open_session(agent->tee_ctx, &arg, NULL);
+	if (ret < 0 || arg.ret) {
+		dev_err(dev, "Can't open tee session: %d / %#x\n", ret, arg.ret);
+		return -EOPNOTSUPP;
+	}
+
+	*tee_session = arg.session;
+
+	return 0;
+}
+
+static void close_session(struct scmi_optee_agent *agent, u32 tee_session)
+{
+	tee_client_close_session(agent->tee_ctx, tee_session);
+}
+
+static int get_capabilities(struct scmi_optee_agent *agent)
+{
+	struct tee_ioctl_invoke_arg arg = { };
+	struct tee_param param[1] = { };
+	u32 caps;
+	u32 tee_session;
+	int ret;
+
+	ret = open_session(agent, &tee_session);
+	if (ret)
+		return ret;
+
+	arg.func = PTA_SCMI_CMD_CAPABILITIES;
+	arg.session = tee_session;
+	arg.num_params = 1;
+
+	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT;
+
+	ret = tee_client_invoke_func(agent->tee_ctx, &arg, param);
+
+	close_session(agent, tee_session);
+
+	if (ret < 0 || arg.ret) {
+		dev_err(agent->dev, "Can't get capabilities: %d / %#x\n", ret, arg.ret);
+		return -EOPNOTSUPP;
+	}
+
+	caps = param[0].u.value.a;
+
+	if (!(caps & (PTA_SCMI_CAPS_SMT_HEADER | PTA_SCMI_CAPS_MSG_HEADER))) {
+		dev_err(agent->dev, "OP-TEE SCMI PTA doesn't support SMT and MSG\n");
+		return -EOPNOTSUPP;
+	}
+
+	agent->caps = caps;
+
+	return 0;
+}
+
+static int get_channel(struct scmi_optee_channel *channel)
+{
+	struct device *dev = scmi_optee_private->dev;
+	struct tee_ioctl_invoke_arg arg = { };
+	struct tee_param param[1] = { };
+	unsigned int caps = 0;
+	int ret;
+
+	if (channel->tee_shm)
+		caps = PTA_SCMI_CAPS_MSG_HEADER;
+	else
+		caps = PTA_SCMI_CAPS_SMT_HEADER;
+
+	arg.func = PTA_SCMI_CMD_GET_CHANNEL;
+	arg.session = channel->tee_session;
+	arg.num_params = 1;
+
+	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT;
+	param[0].u.value.a = channel->channel_id;
+	param[0].u.value.b = caps;
+
+	ret = tee_client_invoke_func(scmi_optee_private->tee_ctx, &arg, param);
+
+	if (ret || arg.ret) {
+		dev_err(dev, "Can't get channel with caps %#x: %d / %#x\n", caps, ret, arg.ret);
+		return -EOPNOTSUPP;
+	}
+
+	/* From now on use channel identifer provided by OP-TEE SCMI service */
+	channel->channel_id = param[0].u.value.a;
+	channel->caps = caps;
+
+	return 0;
+}
+
+static int invoke_process_smt_channel(struct scmi_optee_channel *channel)
+{
+	struct tee_ioctl_invoke_arg arg = {
+		.func = PTA_SCMI_CMD_PROCESS_SMT_CHANNEL,
+		.session = channel->tee_session,
+		.num_params = 1,
+	};
+	struct tee_param param[1] = { };
+	int ret;
+
+	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
+	param[0].u.value.a = channel->channel_id;
+
+	ret = tee_client_invoke_func(scmi_optee_private->tee_ctx, &arg, param);
+	if (ret < 0 || arg.ret) {
+		dev_err(scmi_optee_private->dev, "Can't invoke channel %u: %d / %#x\n",
+			channel->channel_id, ret, arg.ret);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int invoke_process_msg_channel(struct scmi_optee_channel *channel, size_t msg_size)
+{
+	struct tee_ioctl_invoke_arg arg = {
+		.func = PTA_SCMI_CMD_PROCESS_MSG_CHANNEL,
+		.session = channel->tee_session,
+		.num_params = 3,
+	};
+	struct tee_param param[3] = { };
+	int ret;
+
+	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
+	param[0].u.value.a = channel->channel_id;
+
+	param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
+	param[1].u.memref.shm = channel->tee_shm;
+	param[1].u.memref.size = msg_size;
+
+	param[2].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
+	param[2].u.memref.shm = channel->tee_shm;
+	param[2].u.memref.size = SCMI_OPTEE_MAX_MSG_SIZE;
+
+	ret = tee_client_invoke_func(scmi_optee_private->tee_ctx, &arg, param);
+	if (ret < 0 || arg.ret) {
+		dev_err(scmi_optee_private->dev, "Can't invoke channel %u: %d / %#x\n",
+			channel->channel_id, ret, arg.ret);
+		return -EIO;
+	}
+
+	/* Save response size */
+	channel->rx_len = param[2].u.memref.size;
+
+	return 0;
+}
+
+static bool scmi_optee_chan_available(struct device_node *of_node, int idx)
+{
+	u32 channel_id;
+
+	return !of_property_read_u32_index(of_node, "linaro,optee-channel-id",
+					   idx, &channel_id);
+}
+
+static void scmi_optee_clear_channel(struct scmi_chan_info *cinfo)
+{
+	struct scmi_optee_channel *channel = cinfo->transport_info;
+
+	if (!channel->tee_shm)
+		core->shmem->clear_channel(channel->req.shmem);
+}
+
+static int setup_dynamic_shmem(struct device *dev, struct scmi_optee_channel *channel)
+{
+	const size_t msg_size = SCMI_OPTEE_MAX_MSG_SIZE;
+	void *shbuf;
+
+	channel->tee_shm = tee_shm_alloc_kernel_buf(scmi_optee_private->tee_ctx, msg_size);
+	if (IS_ERR(channel->tee_shm)) {
+		dev_err(channel->cinfo->dev, "shmem allocation failed\n");
+		return -ENOMEM;
+	}
+
+	shbuf = tee_shm_get_va(channel->tee_shm, 0);
+	memset(shbuf, 0, msg_size);
+	channel->req.msg = shbuf;
+	channel->rx_len = msg_size;
+
+	return 0;
+}
+
+static int setup_static_shmem(struct device *dev, struct scmi_chan_info *cinfo,
+			      struct scmi_optee_channel *channel)
+{
+	channel->req.shmem = core->shmem->setup_iomap(cinfo, dev, true, NULL);
+	if (IS_ERR(channel->req.shmem))
+		return PTR_ERR(channel->req.shmem);
+
+	return 0;
+}
+
+static int setup_shmem(struct device *dev, struct scmi_chan_info *cinfo,
+		       struct scmi_optee_channel *channel)
+{
+	if (of_property_present(cinfo->dev->of_node, "shmem"))
+		return setup_static_shmem(dev, cinfo, channel);
+	else
+		return setup_dynamic_shmem(dev, channel);
+}
+
+static int scmi_optee_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, bool tx)
+{
+	struct scmi_optee_channel *channel;
+	uint32_t channel_id;
+	int ret;
+
+	if (!tx)
+		return -ENODEV;
+
+	channel = devm_kzalloc(dev, sizeof(*channel), GFP_KERNEL);
+	if (!channel)
+		return -ENOMEM;
+
+	ret = of_property_read_u32_index(cinfo->dev->of_node, "linaro,optee-channel-id",
+					 0, &channel_id);
+	if (ret)
+		return ret;
+
+	cinfo->transport_info = channel;
+	channel->cinfo = cinfo;
+	channel->channel_id = channel_id;
+	mutex_init(&channel->mu);
+
+	ret = setup_shmem(dev, cinfo, channel);
+	if (ret)
+		return ret;
+
+	ret = open_session(scmi_optee_private, &channel->tee_session);
+	if (ret)
+		goto err_free_shm;
+
+	ret = tee_client_system_session(scmi_optee_private->tee_ctx, channel->tee_session);
+	if (ret)
+		dev_warn(dev, "Could not switch to system session, do best effort\n");
+
+	ret = get_channel(channel);
+	if (ret)
+		goto err_close_sess;
+
+	/* Enable polling */
+	cinfo->no_completion_irq = true;
+
+	mutex_lock(&scmi_optee_private->mu);
+	list_add(&channel->link, &scmi_optee_private->channel_list);
+	mutex_unlock(&scmi_optee_private->mu);
+
+	return 0;
+
+err_close_sess:
+	close_session(scmi_optee_private, channel->tee_session);
+err_free_shm:
+	if (channel->tee_shm)
+		tee_shm_free(channel->tee_shm);
+
+	return ret;
+}
+
+static int scmi_optee_chan_free(int id, void *p, void *data)
+{
+	struct scmi_chan_info *cinfo = p;
+	struct scmi_optee_channel *channel = cinfo->transport_info;
+
+	/*
+	 * Different protocols might share the same chan info, so a previous
+	 * call might have already freed the structure.
+	 */
+	if (!channel)
+		return 0;
+
+	mutex_lock(&scmi_optee_private->mu);
+	list_del(&channel->link);
+	mutex_unlock(&scmi_optee_private->mu);
+
+	close_session(scmi_optee_private, channel->tee_session);
+
+	if (channel->tee_shm) {
+		tee_shm_free(channel->tee_shm);
+		channel->tee_shm = NULL;
+	}
+
+	cinfo->transport_info = NULL;
+	channel->cinfo = NULL;
+
+	return 0;
+}
+
+static int scmi_optee_send_message(struct scmi_chan_info *cinfo,
+				   struct scmi_xfer *xfer)
+{
+	struct scmi_optee_channel *channel = cinfo->transport_info;
+	int ret;
+
+	mutex_lock(&channel->mu);
+
+	if (channel->tee_shm) {
+		core->msg->tx_prepare(channel->req.msg, xfer);
+		ret = invoke_process_msg_channel(channel,
+						 core->msg->command_size(xfer));
+	} else {
+		core->shmem->tx_prepare(channel->req.shmem, xfer, cinfo);
+		ret = invoke_process_smt_channel(channel);
+	}
+
+	if (ret)
+		mutex_unlock(&channel->mu);
+
+	return ret;
+}
+
+static void scmi_optee_fetch_response(struct scmi_chan_info *cinfo,
+				      struct scmi_xfer *xfer)
+{
+	struct scmi_optee_channel *channel = cinfo->transport_info;
+
+	if (channel->tee_shm)
+		core->msg->fetch_response(channel->req.msg,
+					  channel->rx_len, xfer);
+	else
+		core->shmem->fetch_response(channel->req.shmem, xfer);
+}
+
+static void scmi_optee_mark_txdone(struct scmi_chan_info *cinfo, int ret,
+				   struct scmi_xfer *__unused)
+{
+	struct scmi_optee_channel *channel = cinfo->transport_info;
+
+	mutex_unlock(&channel->mu);
+}
+
+static struct scmi_transport_ops scmi_optee_ops = {
+	.chan_available = scmi_optee_chan_available,
+	.chan_setup = scmi_optee_chan_setup,
+	.chan_free = scmi_optee_chan_free,
+	.send_message = scmi_optee_send_message,
+	.mark_txdone = scmi_optee_mark_txdone,
+	.fetch_response = scmi_optee_fetch_response,
+	.clear_channel = scmi_optee_clear_channel,
+};
+
+static int scmi_optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
+{
+	return ver->impl_id == TEE_IMPL_ID_OPTEE;
+}
+
+static struct scmi_desc scmi_optee_desc = {
+	.ops = &scmi_optee_ops,
+	.max_rx_timeout_ms = 30,
+	.max_msg = 20,
+	.max_msg_size = SCMI_OPTEE_MAX_MSG_SIZE,
+	.sync_cmds_completed_on_ret = true,
+};
+
+static const struct of_device_id scmi_of_match[] = {
+	{ .compatible = "linaro,scmi-optee" },
+	{ /* Sentinel */ },
+};
+
+DEFINE_SCMI_TRANSPORT_DRIVER(scmi_optee, scmi_optee_driver, scmi_optee_desc,
+			     scmi_of_match, core);
+
+static int scmi_optee_service_probe(struct device *dev)
+{
+	struct scmi_optee_agent *agent;
+	struct tee_context *tee_ctx;
+	int ret;
+
+	/* Only one SCMI OP-TEE device allowed */
+	if (scmi_optee_private) {
+		dev_err(dev, "An SCMI OP-TEE device was already initialized: only one allowed\n");
+		return -EBUSY;
+	}
+
+	tee_ctx = tee_client_open_context(NULL, scmi_optee_ctx_match, NULL, NULL);
+	if (IS_ERR(tee_ctx))
+		return -ENODEV;
+
+	agent = devm_kzalloc(dev, sizeof(*agent), GFP_KERNEL);
+	if (!agent) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	agent->dev = dev;
+	agent->tee_ctx = tee_ctx;
+	INIT_LIST_HEAD(&agent->channel_list);
+	mutex_init(&agent->mu);
+
+	ret = get_capabilities(agent);
+	if (ret)
+		goto err;
+
+	/* Ensure agent resources are all visible before scmi_optee_private is */
+	smp_mb();
+	scmi_optee_private = agent;
+
+	ret = platform_driver_register(&scmi_optee_driver);
+	if (ret) {
+		scmi_optee_private = NULL;
+		goto err;
+	}
+
+	return 0;
+
+err:
+	tee_client_close_context(tee_ctx);
+
+	return ret;
+}
+
+static int scmi_optee_service_remove(struct device *dev)
+{
+	struct scmi_optee_agent *agent = scmi_optee_private;
+
+	if (!scmi_optee_private)
+		return -EINVAL;
+
+	platform_driver_unregister(&scmi_optee_driver);
+
+	if (!list_empty(&scmi_optee_private->channel_list))
+		return -EBUSY;
+
+	/* Ensure cleared reference is visible before resources are released */
+	smp_store_mb(scmi_optee_private, NULL);
+
+	tee_client_close_context(agent->tee_ctx);
+
+	return 0;
+}
+
+static const struct tee_client_device_id scmi_optee_service_id[] = {
+	{
+		UUID_INIT(0xa8cfe406, 0xd4f5, 0x4a2e,
+			  0x9f, 0x8d, 0xa2, 0x5d, 0xc7, 0x54, 0xc0, 0x99)
+	},
+	{ }
+};
+
+MODULE_DEVICE_TABLE(tee, scmi_optee_service_id);
+
+static struct tee_client_driver scmi_optee_service_driver = {
+	.id_table	= scmi_optee_service_id,
+	.driver		= {
+		.name = "scmi-optee",
+		.bus = &tee_bus_type,
+		.probe = scmi_optee_service_probe,
+		.remove = scmi_optee_service_remove,
+	},
+};
+
+static int __init scmi_transport_optee_init(void)
+{
+	return driver_register(&scmi_optee_service_driver.driver);
+}
+module_init(scmi_transport_optee_init);
+
+static void __exit scmi_transport_optee_exit(void)
+{
+	driver_unregister(&scmi_optee_service_driver.driver);
+}
+module_exit(scmi_transport_optee_exit);
+
+MODULE_AUTHOR("Etienne Carriere <etienne.carriere@foss.st.com>");
+MODULE_DESCRIPTION("SCMI OPTEE Transport driver");
+MODULE_LICENSE("GPL");