1 files changed, 312 insertions, 0 deletions
diff --git a/drivers/firmware/scmi/optee_agent.c b/drivers/firmware/scmi/optee_agent.c
new file mode 100644
index 0000000000..1f26592234
--- /dev/null
+++ b/drivers/firmware/scmi/optee_agent.c
@@ -0,0 +1,312 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020-2021 Linaro Limited.
+ */
+
+#define LOG_CATEGORY UCLASS_SCMI_AGENT
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <scmi_agent.h>
+#include <scmi_agent-uclass.h>
+#include <string.h>
+#include <tee.h>
+#include <asm/types.h>
+#include <dm/device_compat.h>
+#include <dm/devres.h>
+#include <linux/arm-smccc.h>
+#include <linux/bug.h>
+#include <linux/compat.h>
+
+#include "smt.h"
+
+#define SCMI_SHM_SIZE		128
+
+/**
+ * struct scmi_optee_channel - Description of an SCMI OP-TEE transport
+ * @channel_id:		Channel identifier
+ * @smt:		Shared memory buffer with synchronisation protocol
+ * @dyn_shm:		True if using dynamically allocated shared memory
+ */
+struct scmi_optee_channel {
+	unsigned int channel_id;
+	struct scmi_smt smt;
+	bool dyn_shm;
+};
+
+/**
+ * struct channel_session - Aggreates SCMI service session context references
+ * @tee:		OP-TEE device to invoke
+ * @tee_session:	OP-TEE session identifier
+ * @tee_shm:		Dynamically allocated OP-TEE shared memory, or NULL
+ * @channel_hdl:	Channel handle provided by OP-TEE SCMI service
+ */
+struct channel_session {
+	struct udevice *tee;
+	u32 tee_session;
+	struct tee_shm *tee_shm;
+	u32 channel_hdl;
+};
+
+#define TA_SCMI_UUID { 0xa8cfe406, 0xd4f5, 0x4a2e, \
+		      { 0x9f, 0x8d, 0xa2, 0x5d, 0xc7, 0x54, 0xc0, 0x99 } }
+
+enum optee_smci_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,
+};
+
+/*
+ * 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.
+ */
+#define PTA_SCMI_CAPS_NONE		0
+#define PTA_SCMI_CAPS_SMT_HEADER	BIT(0)
+
+static int open_channel(struct udevice *dev, struct channel_session *sess)
+{
+	const struct tee_optee_ta_uuid uuid = TA_SCMI_UUID;
+	struct scmi_optee_channel *chan = dev_get_plat(dev);
+	struct tee_open_session_arg sess_arg = { };
+	struct tee_invoke_arg cmd_arg = { };
+	struct tee_param param[1] = { };
+	int ret;
+
+	memset(sess, 0, sizeof(sess));
+
+	sess->tee = tee_find_device(NULL, NULL, NULL, NULL);
+	if (!sess->tee)
+		return -ENODEV;
+
+	sess_arg.clnt_login = TEE_LOGIN_REE_KERNEL;
+	tee_optee_ta_uuid_to_octets(sess_arg.uuid, &uuid);
+
+	ret = tee_open_session(sess->tee, &sess_arg, 0, NULL);
+	if (ret) {
+		dev_err(dev, "can't open session: %d\n", ret);
+		return ret;
+	}
+
+	cmd_arg.func = PTA_SCMI_CMD_GET_CHANNEL;
+	cmd_arg.session = sess_arg.session;
+
+	param[0].attr = TEE_PARAM_ATTR_TYPE_VALUE_INOUT;
+	param[0].u.value.a = chan->channel_id;
+	param[0].u.value.b = PTA_SCMI_CAPS_SMT_HEADER;
+
+	ret = tee_invoke_func(sess->tee, &cmd_arg, ARRAY_SIZE(param), param);
+	if (ret || cmd_arg.ret) {
+		dev_err(dev, "Invoke failed: %d, 0x%x\n", ret, cmd_arg.ret);
+		if (!ret)
+			ret = -EPROTO;
+
+		tee_close_session(sess->tee, sess_arg.session);
+		return ret;
+	}
+
+	sess->tee_session = sess_arg.session;
+	sess->channel_hdl = param[0].u.value.a;
+
+	return 0;
+}
+
+static void close_channel(struct channel_session *sess)
+{
+	tee_close_session(sess->tee, sess->tee_session);
+}
+
+static int invoke_cmd(struct udevice *dev, struct channel_session *sess,
+		      struct scmi_msg *msg)
+{
+	struct scmi_optee_channel *chan = dev_get_plat(dev);
+	struct tee_invoke_arg arg = { };
+	struct tee_param param[2] = { };
+	int ret;
+
+	scmi_write_msg_to_smt(dev, &chan->smt, msg);
+
+	arg.session = sess->tee_session;
+	param[0].attr = TEE_PARAM_ATTR_TYPE_VALUE_INPUT;
+	param[0].u.value.a = sess->channel_hdl;
+
+	if (chan->dyn_shm) {
+		arg.func = PTA_SCMI_CMD_PROCESS_SMT_CHANNEL_MESSAGE;
+		param[1].attr = TEE_PARAM_ATTR_TYPE_MEMREF_INOUT;
+		param[1].u.memref.shm = sess->tee_shm;
+		param[1].u.memref.size = SCMI_SHM_SIZE;
+	} else {
+		arg.func = PTA_SCMI_CMD_PROCESS_SMT_CHANNEL;
+	}
+
+	ret = tee_invoke_func(sess->tee, &arg, ARRAY_SIZE(param), param);
+	if (ret || arg.ret) {
+		if (!ret)
+			ret = -EPROTO;
+	} else {
+		ret = scmi_read_resp_from_smt(dev, &chan->smt, msg);
+	}
+
+	scmi_clear_smt_channel(&chan->smt);
+
+	return ret;
+}
+
+static int prepare_shm(struct udevice *dev, struct channel_session *sess)
+{
+	struct scmi_optee_channel *chan = dev_get_plat(dev);
+	int ret;
+
+	/* Static shm is already prepared by the firmware: nothing to do */
+	if (!chan->dyn_shm)
+		return 0;
+
+	chan->smt.size = SCMI_SHM_SIZE;
+
+	ret = tee_shm_alloc(sess->tee, chan->smt.size, 0, &sess->tee_shm);
+	if (ret) {
+		dev_err(dev, "Failed to allocated shmem: %d\n", ret);
+		return ret;
+	}
+
+	chan->smt.buf = sess->tee_shm->addr;
+
+	/* Initialize shm buffer for message exchanges */
+	scmi_clear_smt_channel(&chan->smt);
+
+	return 0;
+}
+
+static void release_shm(struct udevice *dev, struct channel_session *sess)
+{
+	struct scmi_optee_channel *chan = dev_get_plat(dev);
+
+	if (chan->dyn_shm)
+		tee_shm_free(sess->tee_shm);
+}
+
+static int scmi_optee_process_msg(struct udevice *dev, struct scmi_msg *msg)
+{
+	struct channel_session sess;
+	int ret;
+
+	ret = open_channel(dev, &sess);
+	if (ret)
+		return ret;
+
+	ret = prepare_shm(dev, &sess);
+	if (ret)
+		goto out;
+
+	ret = invoke_cmd(dev, &sess, msg);
+
+	release_shm(dev, &sess);
+
+out:
+	close_channel(&sess);
+
+	return ret;
+}
+
+static int scmi_optee_of_to_plat(struct udevice *dev)
+{
+	struct scmi_optee_channel *chan = dev_get_plat(dev);
+	int ret;
+
+	if (dev_read_u32(dev, "linaro,optee-channel-id", &chan->channel_id)) {
+		dev_err(dev, "Missing property linaro,optee-channel-id\n");
+		return -EINVAL;
+	}
+
+	if (dev_read_prop(dev, "shmem", NULL)) {
+		ret = scmi_dt_get_smt_buffer(dev, &chan->smt);
+		if (ret) {
+			dev_err(dev, "Failed to get smt resources: %d\n", ret);
+			return ret;
+		}
+		chan->dyn_shm = false;
+	} else {
+		chan->dyn_shm = true;
+	}
+
+	return 0;
+}
+
+static int scmi_optee_probe(struct udevice *dev)
+{
+	struct channel_session sess;
+	int ret;
+
+	/* Check OP-TEE service acknowledges the SCMI channel */
+	ret = open_channel(dev, &sess);
+	if (!ret)
+		close_channel(&sess);
+
+	return ret;
+}
+
+static const struct udevice_id scmi_optee_ids[] = {
+	{ .compatible = "linaro,scmi-optee" },
+	{ }
+};
+
+static const struct scmi_agent_ops scmi_optee_ops = {
+	.process_msg = scmi_optee_process_msg,
+};
+
+U_BOOT_DRIVER(scmi_optee) = {
+	.name		= "scmi-over-optee",
+	.id		= UCLASS_SCMI_AGENT,
+	.of_match	= scmi_optee_ids,
+	.plat_auto	= sizeof(struct scmi_optee_channel),
+	.of_to_plat	= scmi_optee_of_to_plat,
+	.probe		= scmi_optee_probe,
+	.flags		= DM_FLAG_OS_PREPARE,
+	.ops		= &scmi_optee_ops,
+};