firmware: qcom: scm: add support for object invocation

Qualcomm TEE (QTEE) hosts Trusted Applications (TAs) and services in
the secure world, accessed via objects. A QTEE client can invoke these
objects to request services. Similarly, QTEE can request services from
the nonsecure world using objects exported to the secure world.

Add low-level primitives to facilitate the invocation of objects hosted
in QTEE, as well as those hosted in the nonsecure world.

If support for object invocation is available, the qcom_scm allocates
a dedicated child platform device. The driver for this device communicates
with QTEE using low-level primitives.

Tested-by: Neil Armstrong <neil.armstrong@linaro.org>
Tested-by: Harshal Dev <quic_hdev@quicinc.com>
Signed-off-by: Amirreza Zarrabi <amirreza.zarrabi@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250911-qcom-tee-using-tee-ss-without-mem-obj-v12-2-17f07a942b8d@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Author: qc-azarrabi

drivers/firmware/qcom/qcom_scm.c

@@ -2093,6 +2093,122 @@ static int qcom_scm_qseecom_init(struct qcom_scm *scm)
 
 #endif /* CONFIG_QCOM_QSEECOM */
 
+/**
+ * qcom_scm_qtee_invoke_smc() - Invoke a QTEE object.
+ * @inbuf: start address of memory area used for inbound buffer.
+ * @inbuf_size: size of the memory area used for inbound buffer.
+ * @outbuf: start address of memory area used for outbound buffer.
+ * @outbuf_size: size of the memory area used for outbound buffer.
+ * @result: result of QTEE object invocation.
+ * @response_type: response type returned by QTEE.
+ *
+ * @response_type determines how the contents of @inbuf and @outbuf
+ * should be processed.
+ *
+ * Return: On success, return 0 or <0 on failure.
+ */
+int qcom_scm_qtee_invoke_smc(phys_addr_t inbuf, size_t inbuf_size,
+			     phys_addr_t outbuf, size_t outbuf_size,
+			     u64 *result, u64 *response_type)
+{
+	struct qcom_scm_desc desc = {
+		.svc = QCOM_SCM_SVC_SMCINVOKE,
+		.cmd = QCOM_SCM_SMCINVOKE_INVOKE,
+		.owner = ARM_SMCCC_OWNER_TRUSTED_OS,
+		.args[0] = inbuf,
+		.args[1] = inbuf_size,
+		.args[2] = outbuf,
+		.args[3] = outbuf_size,
+		.arginfo = QCOM_SCM_ARGS(4, QCOM_SCM_RW, QCOM_SCM_VAL,
+					 QCOM_SCM_RW, QCOM_SCM_VAL),
+	};
+	struct qcom_scm_res res;
+	int ret;
+
+	ret = qcom_scm_call(__scm->dev, &desc, &res);
+	if (ret)
+		return ret;
+
+	if (response_type)
+		*response_type = res.result[0];
+
+	if (result)
+		*result = res.result[1];
+
+	return 0;
+}
+EXPORT_SYMBOL(qcom_scm_qtee_invoke_smc);
+
+/**
+ * qcom_scm_qtee_callback_response() - Submit response for callback request.
+ * @buf: start address of memory area used for outbound buffer.
+ * @buf_size: size of the memory area used for outbound buffer.
+ * @result: Result of QTEE object invocation.
+ * @response_type: Response type returned by QTEE.
+ *
+ * @response_type determines how the contents of @buf should be processed.
+ *
+ * Return: On success, return 0 or <0 on failure.
+ */
+int qcom_scm_qtee_callback_response(phys_addr_t buf, size_t buf_size,
+				    u64 *result, u64 *response_type)
+{
+	struct qcom_scm_desc desc = {
+		.svc = QCOM_SCM_SVC_SMCINVOKE,
+		.cmd = QCOM_SCM_SMCINVOKE_CB_RSP,
+		.owner = ARM_SMCCC_OWNER_TRUSTED_OS,
+		.args[0] = buf,
+		.args[1] = buf_size,
+		.arginfo = QCOM_SCM_ARGS(2, QCOM_SCM_RW, QCOM_SCM_VAL),
+	};
+	struct qcom_scm_res res;
+	int ret;
+
+	ret = qcom_scm_call(__scm->dev, &desc, &res);
+	if (ret)
+		return ret;
+
+	if (response_type)
+		*response_type = res.result[0];
+
+	if (result)
+		*result = res.result[1];
+
+	return 0;
+}
+EXPORT_SYMBOL(qcom_scm_qtee_callback_response);
+
+static void qcom_scm_qtee_free(void *data)
+{
+	struct platform_device *qtee_dev = data;
+
+	platform_device_unregister(qtee_dev);
+}
+
+static void qcom_scm_qtee_init(struct qcom_scm *scm)
+{
+	struct platform_device *qtee_dev;
+	u64 result, response_type;
+	int ret;
+
+	/*
+	 * Probe for smcinvoke support. This will fail due to invalid buffers,
+	 * but first, it checks whether the call is supported in QTEE syscall
+	 * handler. If it is not supported, -EIO is returned.
+	 */
+	ret = qcom_scm_qtee_invoke_smc(0, 0, 0, 0, &result, &response_type);
+	if (ret == -EIO)
+		return;
+
+	/* Setup QTEE interface device. */
+	qtee_dev = platform_device_register_data(scm->dev, "qcomtee",
+						 PLATFORM_DEVID_NONE, NULL, 0);
+	if (IS_ERR(qtee_dev))
+		return;
+
+	devm_add_action_or_reset(scm->dev, qcom_scm_qtee_free, qtee_dev);
+}
+
 /**
  * qcom_scm_is_available() - Checks if SCM is available
  */
@@ -2325,6 +2441,9 @@ static int qcom_scm_probe(struct platform_device *pdev)
 	ret = qcom_scm_qseecom_init(scm);
 	WARN(ret < 0, "failed to initialize qseecom: %d\n", ret);
 
+	/* Initialize the QTEE object interface. */
+	qcom_scm_qtee_init(scm);
+
 	return 0;
 }
 

drivers/firmware/qcom/qcom_scm.h

@@ -156,6 +156,13 @@ int qcom_scm_shm_bridge_enable(struct device *scm_dev);
 #define QCOM_SCM_SVC_GPU			0x28
 #define QCOM_SCM_SVC_GPU_INIT_REGS		0x01
 
+/* ARM_SMCCC_OWNER_TRUSTED_OS calls */
+
+#define QCOM_SCM_SVC_SMCINVOKE			0x06
+#define QCOM_SCM_SMCINVOKE_INVOKE_LEGACY	0x00
+#define QCOM_SCM_SMCINVOKE_CB_RSP		0x01
+#define QCOM_SCM_SMCINVOKE_INVOKE		0x02
+
 /* common error codes */
 #define QCOM_SCM_V2_EBUSY	-12
 #define QCOM_SCM_ENOMEM		-5

include/linux/firmware/qcom/qcom_scm.h

@@ -175,4 +175,10 @@ static inline int qcom_scm_qseecom_app_send(u32 app_id,
 
 #endif /* CONFIG_QCOM_QSEECOM */
 
+int qcom_scm_qtee_invoke_smc(phys_addr_t inbuf, size_t inbuf_size,
+			     phys_addr_t outbuf, size_t outbuf_size,
+			     u64 *result, u64 *response_type);
+int qcom_scm_qtee_callback_response(phys_addr_t buf, size_t buf_size,
+				    u64 *result, u64 *response_type);
+
 #endif