ipc: Remove unnecessary cache manipulation

The buffer containing the payload of the sent IPC message should always be
placed in shared memory (non-cached). Remove the unnecessary is_shared
field from the ipc_msg structure and the code responsible for performing
cache memory operations.

Signed-off-by: Adrian Warecki <adrian.warecki@intel.com>

Author: softwarecki

src/include/sof/ipc/msg.h

@@ -34,8 +34,7 @@ struct ipc_msg {
 	uint32_t header;	/* specific to platform */
 	uint32_t extension;	/* extension specific to platform */
 	uint32_t tx_size;	/* payload size in bytes */
-	void *tx_data;		/* pointer to payload data */
-	bool is_shared;		/* the message is shared cross-core */
+	void *tx_data;		/* pointer to payload data, must be in a non-cached memory */
 	struct list_item list;
 };
 

src/ipc/ipc-common.c

@@ -216,15 +216,6 @@ void ipc_msg_send(struct ipc_msg *msg, void *data, bool high_priority)
 	    msg->tx_data != data) {
 		ret = memcpy_s(msg->tx_data, msg->tx_size, data, msg->tx_size);
 		assert(!ret);
-		if (!cpu_is_primary(cpu_get_id())) {
-			/* Write back data to memory to maintain coherence between cores.
-			 * The response was prepared on a secondary core but will be sent
-			 * to the host from the primary core.
-			 */
-			dcache_writeback_region((__sparse_force void __sparse_cache *)msg->tx_data,
-						msg->tx_size);
-			msg->is_shared = true;
-		}
 	}
 
 	/*

src/ipc/ipc4/handler.c

@@ -72,9 +72,9 @@ struct ipc4_msg_data {
 static struct ipc4_msg_data msg_data;
 
 /* fw sends a fw ipc message to send the status of the last host ipc message */
-static struct ipc_msg msg_reply = {0, 0, 0, 0, false, LIST_INIT(msg_reply.list)};
+static struct ipc_msg msg_reply = {0, 0, 0, 0, LIST_INIT(msg_reply.list)};
 
-static struct ipc_msg msg_notify = {0, 0, 0, 0, false, LIST_INIT(msg_notify.list)};
+static struct ipc_msg msg_notify = {0, 0, 0, 0, LIST_INIT(msg_notify.list)};
 
 #if CONFIG_LIBRARY
 static inline struct ipc4_message_request *ipc4_get_message_request(void)
@@ -1471,18 +1471,8 @@ struct ipc_cmd_hdr *ipc_prepare_to_send(const struct ipc_msg *msg)
 	msg_data.msg_out.pri = msg->header;
 	msg_data.msg_out.ext = msg->extension;
 
-	if (msg->tx_size) {
-		/* Invalidate cache to ensure we read the latest data from memory.
-		 * The response was prepared on a secondary core but will be sent
-		 * to the host from the primary core.
-		 */
-		if (msg->is_shared) {
-			dcache_invalidate_region((__sparse_force void __sparse_cache *)msg->tx_data,
-						 msg->tx_size);
-		}
-
+	if (msg->tx_size)
 		mailbox_dspbox_write(0, (uint32_t *)msg->tx_data, msg->tx_size);
-	}
 
 	return &msg_data.msg_out;
 }
@@ -1515,7 +1505,6 @@ void ipc_send_panic_notification(void)
 {
 	msg_notify.header = SOF_IPC4_NOTIF_HEADER(SOF_IPC4_EXCEPTION_CAUGHT);
 	msg_notify.extension = cpu_get_id();
-	msg_notify.is_shared = !cpu_is_primary(cpu_get_id());
 	msg_notify.tx_size = 0;
 	msg_notify.tx_data = NULL;
 	list_init(&msg_notify.list);
@@ -1548,7 +1537,6 @@ void ipc_send_buffer_status_notify(void)
 	msg_notify.header = SOF_IPC4_NOTIF_HEADER(SOF_IPC4_NOTIFY_LOG_BUFFER_STATUS);
 	msg_notify.extension = 0;
 	msg_notify.tx_size = 0;
-	msg_notify.is_shared = false;
 
 	tr_dbg(&ipc_tr, "tx-notify\t: %#x|%#x", msg_notify.header, msg_notify.extension);
 

src/library_manager/lib_notification.c

@@ -73,7 +73,6 @@ struct ipc_msg *lib_notif_msg_init(uint32_t header, uint32_t size)
 	/* Update header and size, since message handle can be reused */
 	msg->header = header;
 	msg->tx_size = size;
-	msg->is_shared = !cpu_is_primary(cpu_get_id());
 	return msg;
 }