firmware: qcom: tzmem: export shm_bridge create/delete

Anyone with access to contiguous physical memory should be able to
share memory with QTEE using shm_bridge.

Tested-by: Neil Armstrong <neil.armstrong@linaro.org>
Tested-by: Harshal Dev <quic_hdev@quicinc.com>
Reviewed-by: Kuldeep Singh <quic_kuldsing@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-v12-1-17f07a942b8d@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

drivers/firmware/qcom/qcom_tzmem.c

@@ -109,7 +109,19 @@ notsupp:
 	return 0;
 }
 
-static int qcom_tzmem_init_area(struct qcom_tzmem_area *area)
+/**
+ * qcom_tzmem_shm_bridge_create() - Create a SHM bridge.
+ * @paddr: Physical address of the memory to share.
+ * @size: Size of the memory to share.
+ * @handle: Handle to the SHM bridge.
+ *
+ * On platforms that support SHM bridge, this function creates a SHM bridge
+ * for the given memory region with QTEE. The handle returned by this function
+ * must be passed to qcom_tzmem_shm_bridge_delete() to free the SHM bridge.
+ *
+ * Return: On success, returns 0; on failure, returns < 0.
+ */
+int qcom_tzmem_shm_bridge_create(phys_addr_t paddr, size_t size, u64 *handle)
 {
 	u64 pfn_and_ns_perm, ipfn_and_s_perm, size_and_flags;
 	int ret;
@@ -117,17 +129,49 @@ static int qcom_tzmem_init_area(struct qcom_tzmem_area *area)
 	if (!qcom_tzmem_using_shm_bridge)
 		return 0;
 
-	pfn_and_ns_perm = (u64)area->paddr | QCOM_SCM_PERM_RW;
-	ipfn_and_s_perm = (u64)area->paddr | QCOM_SCM_PERM_RW;
-	size_and_flags = area->size | (1 << QCOM_SHM_BRIDGE_NUM_VM_SHIFT);
+	pfn_and_ns_perm = paddr | QCOM_SCM_PERM_RW;
+	ipfn_and_s_perm = paddr | QCOM_SCM_PERM_RW;
+	size_and_flags = size | (1 << QCOM_SHM_BRIDGE_NUM_VM_SHIFT);
+
+	ret = qcom_scm_shm_bridge_create(pfn_and_ns_perm, ipfn_and_s_perm,
+					 size_and_flags, QCOM_SCM_VMID_HLOS,
+					 handle);
+	if (ret) {
+		dev_err(qcom_tzmem_dev,
+			"SHM Bridge failed: ret %d paddr 0x%pa, size %zu\n",
+			ret, &paddr, size);
+
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(qcom_tzmem_shm_bridge_create);
+
+/**
+ * qcom_tzmem_shm_bridge_delete() - Delete a SHM bridge.
+ * @handle: Handle to the SHM bridge.
+ *
+ * On platforms that support SHM bridge, this function deletes the SHM bridge
+ * for the given memory region. The handle must be the same as the one
+ * returned by qcom_tzmem_shm_bridge_create().
+ */
+void qcom_tzmem_shm_bridge_delete(u64 handle)
+{
+	if (qcom_tzmem_using_shm_bridge)
+		qcom_scm_shm_bridge_delete(handle);
+}
+EXPORT_SYMBOL_GPL(qcom_tzmem_shm_bridge_delete);
+
+static int qcom_tzmem_init_area(struct qcom_tzmem_area *area)
+{
+	int ret;
 
 	u64 *handle __free(kfree) = kzalloc(sizeof(*handle), GFP_KERNEL);
 	if (!handle)
 		return -ENOMEM;
 
-	ret = qcom_scm_shm_bridge_create(pfn_and_ns_perm, ipfn_and_s_perm,
-					 size_and_flags, QCOM_SCM_VMID_HLOS,
-					 handle);
+	ret = qcom_tzmem_shm_bridge_create(area->paddr, area->size, handle);
 	if (ret)
 		return ret;
 
@@ -140,10 +184,7 @@ static void qcom_tzmem_cleanup_area(struct qcom_tzmem_area *area)
 {
 	u64 *handle = area->priv;
 
-	if (!qcom_tzmem_using_shm_bridge)
-		return;
-
-	qcom_scm_shm_bridge_delete(*handle);
+	qcom_tzmem_shm_bridge_delete(*handle);
 	kfree(handle);
 }
 

include/linux/firmware/qcom/qcom_tzmem.h

@@ -53,4 +53,19 @@ DEFINE_FREE(qcom_tzmem, void *, if (_T) qcom_tzmem_free(_T))
 
 phys_addr_t qcom_tzmem_to_phys(void *ptr);
 
+#if IS_ENABLED(CONFIG_QCOM_TZMEM_MODE_SHMBRIDGE)
+int qcom_tzmem_shm_bridge_create(phys_addr_t paddr, size_t size, u64 *handle);
+void qcom_tzmem_shm_bridge_delete(u64 handle);
+#else
+static inline int qcom_tzmem_shm_bridge_create(phys_addr_t paddr,
+					       size_t size, u64 *handle)
+{
+	return 0;
+}
+
+static inline void qcom_tzmem_shm_bridge_delete(u64 handle)
+{
+}
+#endif
+
 #endif /* __QCOM_TZMEM */