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>

diff --git a/drivers/firmware/qcom/qcom_tzmem.c b/drivers/firmware/qcom/qcom_tzmem.c
index ea0a35355657064b1c08a6ebed7cfb483a60dd3f..186511ced9245ed2c2473a7a2ea6e6306dad0fce 100644 (file)
--- a/drivers/firmware/qcom/qcom_tzmem.c
+++ b/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);
 }
 

diff --git a/include/linux/firmware/qcom/qcom_tzmem.h b/include/linux/firmware/qcom/qcom_tzmem.h
index b83b63a0c049b75d6c8e3fc57e822360217e2754..48ac0e5454c7fcb1f763d4881e284ad07cad40b6 100644 (file)
--- a/include/linux/firmware/qcom/qcom_tzmem.h
+++ b/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 */