ipc: ipc3: Add support for SOF_IPC_FW_READY sequence initiated by host

In the case of i.MX93 Linux will send an IPC_FW_READY
message to SOF and will expect to receive the following information
in the hostbox:
	1) reply structure
	2) sof_ipc_fw_ready structure
	3) sof_ipc_fw_ready structure

This flow is required because the FW (due to Jailhouse's design)
will be up before the platform driver from Linux so the
SOF_IPC_FW_READY sequence can't be initiated by SOF.

Signed-off-by: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>

src/ipc/ipc3/handler.c

@@ -1603,6 +1603,35 @@ void ipc_boot_complete_msg(struct ipc_cmd_hdr *header, uint32_t data)
 	header->dat[1] = data;
 }
 
+static int ipc_fw_ready(void)
+{
+#ifdef CONFIG_IMX93_A55
+	/* VERY IMPORTANT:
+	 *	* due to how the FW is started, i.MX93 has the
+	 *	following flow (please note that the host driver
+	 *	is blacklisted and inserted later on):
+	 *
+	 *	1) Linux kernel boots and user space becomes
+	 *	available.
+	 *	2) FW is started (through Jailhouse) => SOF is running
+	 *	4) Host driver module is inserted.
+	 *	5) Host platform driver sends SOF_IPC_FW_READY and
+	 *	expects SOF to send the SOF_IPC_FW_READY
+	 *	message, the window regions and the reply
+	 *	header in the following order:
+	 *		1) reply structure
+	 *		2) sof_ipc_fw_ready structure
+	 *		3) windows structure
+	 *	(all of the above information is written
+	 *	contiguously in the hostbox)
+	 */
+	return platform_boot_complete(0);
+#else
+	/* any other platform should not receive SOF_IPC_FW_READY from host */
+	return -EINVAL;
+#endif /* CONFIG_IMX93_A55 */
+}
+
 /*
  * Global IPC Operations.
  */
@@ -1663,6 +1692,9 @@ void ipc_cmd(struct ipc_cmd_hdr *_hdr)
 	case SOF_IPC_GLB_DEBUG:
 		ret = ipc_glb_debug_message(hdr->cmd);
 		break;
+	case SOF_IPC_FW_READY:
+		ret = ipc_fw_ready();
+		break;
 #if CONFIG_DEBUG
 	case SOF_IPC_GLB_TEST:
 		ret = ipc_glb_test_message(hdr->cmd);