[PATCH v4 05/11] firmware: qcom: scm: add support for object invocation

Amirreza Zarrabi
2025-04-29T06:07:06Z

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.

Signed-off-by: Amirreza Zarrabi <amirreza.zarrabi@oss.qualcomm.com>
---
drivers/firmware/qcom/qcom_scm.c | 128 +++++++++++++++++++++++++++++++++
drivers/firmware/qcom/qcom_scm.h | 7 ++
include/linux/firmware/qcom/qcom_scm.h | 27 +++++++
3 files changed, 162 insertions(+)

diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
index fc4d67e4c4a6..bff1b0d3306e 100644
--- a/drivers/firmware/qcom/qcom_scm.c
+++ b/drivers/firmware/qcom/qcom_scm.c
@@ -2084,6 +2084,124 @@ static int qcom_scm_qseecom_init(struct qcom_scm *scm)

#endif /* CONFIG_QCOM_QSEECOM */

+#ifdef CONFIG_QCOMTEE
+
+/**
+ * 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;
+
+ *response_type = res.result[0];
+ *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;
+
+ *response_type = res.result[0];
+ *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 int qcom_scm_qtee_init(struct qcom_scm *scm)
+{
+ struct platform_device *qtee_dev;
+ int ret;
+
+ /* Setup QTEE interface device. */
+ qtee_dev = platform_device_alloc("qcomtee", -1);
+ if (!qtee_dev)
+ return -ENOMEM;
+
+ qtee_dev->dev.parent = scm->dev;
+
+ ret = platform_device_add(qtee_dev);
+ if (ret) {
+ platform_device_put(qtee_dev);
+ return ret;
+ }
+
+ return devm_add_action_or_reset(scm->dev, qcom_scm_qtee_free, qtee_dev);
+}
+
+#else
+
+static int qcom_scm_qtee_init(struct qcom_scm *scm)
+{
+ return 0;
+}
+
+#endif /* CONFIG_QCOMTEE */
+
/**
* qcom_scm_is_available() - Checks if SCM is available
*/
@@ -2319,6 +2437,16 @@ 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.
+ *
+ * This only represents the availability for QTEE object invocation
+ * and callback support. On failure, ignore the result. Any subsystem
+ * depending on it may fail if it tries to access this interface.
+ */
+ ret = qcom_scm_qtee_init(scm);
+ WARN(ret < 0, "failed to initialize qcomtee: %d\n", ret);
+
return 0;

err:
diff --git a/drivers/firmware/qcom/qcom_scm.h b/drivers/firmware/qcom/qcom_scm.h
index 097369d38b84..a25202e99f7c 100644
--- a/drivers/firmware/qcom/qcom_scm.h
+++ b/drivers/firmware/qcom/qcom_scm.h
@@ -152,6 +152,13 @@ struct qcom_tzmem_pool *qcom_scm_get_tzmem_pool(void);
#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
diff --git a/include/linux/firmware/qcom/qcom_scm.h b/include/linux/firmware/qcom/qcom_scm.h
index 983e1591bbba..bf5e64f6deba 100644
--- a/include/linux/firmware/qcom/qcom_scm.h
+++ b/include/linux/firmware/qcom/qcom_scm.h
@@ -176,4 +176,31 @@ static inline int qcom_scm_qseecom_app_send(u32 app_id,

#endif /* CONFIG_QCOM_QSEECOM */

+#ifdef CONFIG_QCOMTEE
+
+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);
+
+#else /* CONFIG_QCOMTEE */
+
+static inline 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)
+{
+ return -EINVAL;
+}
+
+static inline int qcom_scm_qtee_callback_response(phys_addr_t buf,
+ size_t buf_size, u64 *result,
+ u64 *response_type)
+{
+ return -EINVAL;
+}
+
+#endif /* CONFIG_QCOMTEE */
+
#endif

--
2.34.1