ipc: gdb: initialise GDB after IPC completion

To avoid timed out IPC on the host side, enter the GDB stub only
after replying to the IPC.

Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>

Author: lyakh

src/include/sof/debug/gdb/gdb.h

@@ -38,8 +38,9 @@
 void gdb_handle_exception(void);
 void gdb_debug_info(unsigned char *str);
 void gdb_init_debug_exception(void);
-void gdb_init(void);
 
 #endif /* CONFIG_GDB_DEBUG */
 
+void gdb_init(void);
+
 #endif /* __SOF_DEBUG_GDB_GDB_H__ */

src/include/sof/ipc/common.h

@@ -247,4 +247,7 @@ void ipc_msg_reply(struct sof_ipc_reply *reply);
  */
 void ipc_complete_cmd(struct ipc *ipc);
 
+/* GDB stub: should enter GDB after completing the IPC processing */
+extern bool ipc_enter_gdb;
+
 #endif /* __SOF_DRIVERS_IPC_H__ */

src/include/sof/ipc/driver.h

@@ -112,4 +112,9 @@ int ipc_platform_poll_is_host_ready(void);
  */
 int ipc_platform_poll_tx_host_msg(struct ipc_msg *msg);
 
+/**
+ * \brief wait for host acknowledgment to an IPC message
+ */
+void ipc_platform_wait_ack(struct ipc *ipc);
+
 #endif

src/ipc/ipc-common.c

@@ -9,6 +9,7 @@
 #include <sof/audio/component_ext.h>
 #include <sof/audio/pipeline.h>
 #include <sof/common.h>
+#include <sof/debug/gdb/gdb.h>
 #include <rtos/idc.h>
 #include <rtos/symbol.h>
 #include <sof/ipc/topology.h>
@@ -361,6 +362,13 @@ void ipc_complete_cmd(struct ipc *ipc)
 	ipc_platform_complete_cmd(ipc);
 }
 
+bool ipc_enter_gdb;
+
+__attribute__((weak)) void ipc_platform_wait_ack(struct ipc *ipc)
+{
+	k_msleep(1);
+}
+
 static void ipc_complete_task(void *data)
 {
 	struct ipc *ipc = data;
@@ -370,6 +378,13 @@ static void ipc_complete_task(void *data)
 	ipc->task_mask &= ~IPC_TASK_INLINE;
 	ipc_complete_cmd(ipc);
 	k_spin_unlock(&ipc->lock, key);
+#if CONFIG_GDBSTUB
+	if (ipc_enter_gdb) {
+		ipc_enter_gdb = false;
+		ipc_platform_wait_ack(ipc);
+		gdb_init();
+	}
+#endif
 }
 
 static enum task_state ipc_do_cmd(void *data)

src/ipc/ipc-zephyr.c

@@ -11,6 +11,8 @@
 
 #include <autoconf.h>
 
+#include <zephyr/kernel.h>
+
 #include <intel_adsp_ipc.h>
 #include <sof/ipc/common.h>
 
@@ -309,3 +311,23 @@ int platform_ipc_init(struct ipc *ipc)
 
 	return 0;
 }
+
+static bool ipc_wait_complete(const struct device *dev, void *arg)
+{
+	k_sem_give(arg);
+	return false;
+}
+
+void ipc_platform_wait_ack(struct ipc *ipc)
+{
+	static struct k_sem ipc_wait_sem;
+
+	k_sem_init(&ipc_wait_sem, 0, 1);
+
+	intel_adsp_ipc_set_done_handler(INTEL_ADSP_IPC_HOST_DEV, ipc_wait_complete, &ipc_wait_sem);
+
+	if (k_sem_take(&ipc_wait_sem, Z_TIMEOUT_MS(10)) == -EAGAIN)
+		tr_err(&ipc_tr, "Timeout waiting for host ack!");
+
+	intel_adsp_ipc_set_done_handler(INTEL_ADSP_IPC_HOST_DEV, NULL, NULL);
+}

src/ipc/ipc3/handler.c

@@ -973,7 +973,7 @@ static int ipc_glb_gdb_debug(uint32_t header)
 	(void) header;
 
 #if CONFIG_GDBSTUB
-	gdb_init();
+	ipc_enter_gdb = true;
 	return 0;
 // TODO: remove old GDB stub?
 #elif CONFIG_GDB_DEBUG