soundwire: bus: export broadcast read/write capability for tests

Provide prototype and export symbol to enable tests. The bus lock is
handled externally to avoid conflicts e.g. between kernel-generated
traffic and test traffic.

Signed-off-by: Pierre-Louis Bossart <[e-mail]>
Signed-off-by: Bard Liao <[e-mail]>
Reviewed-by: Kai Vehmanen <[e-mail]>
Reviewed-by: Guennadi Liakhovetski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/soundwire/bus.c

···
 	return ret;
 }
 
+static int sdw_transfer_unlocked(struct sdw_bus *bus, struct sdw_msg *msg)
+{
+	int ret;
+
+	ret = do_transfer(bus, msg);
+	if (ret != 0 && ret != -ENODATA)
+		dev_err(bus->dev, "trf on Slave %d failed:%d\n",
+			msg->dev_num, ret);
+
+	if (msg->page)
+		sdw_reset_page(bus, msg->dev_num);
+
+	return ret;
+}
+
 /**
  * sdw_transfer() - Synchronous transfer message to a SDW Slave device
  * @bus: SDW bus
···
 
 	mutex_lock(&bus->msg_lock);
 
-	ret = do_transfer(bus, msg);
-	if (ret != 0 && ret != -ENODATA)
-		dev_err(bus->dev, "trf on Slave %d failed:%d\n",
-			msg->dev_num, ret);
-
-	if (msg->page)
-		sdw_reset_page(bus, msg->dev_num);
+	ret = sdw_transfer_unlocked(bus, msg);
 
 	mutex_unlock(&bus->msg_lock);
 
···
 
 	return sdw_transfer(bus, &msg);
 }
+
+int sdw_bread_no_pm_unlocked(struct sdw_bus *bus, u16 dev_num, u32 addr)
+{
+	struct sdw_msg msg;
+	u8 buf;
+	int ret;
+
+	ret = sdw_fill_msg(&msg, NULL, addr, 1, dev_num,
+			   SDW_MSG_FLAG_READ, &buf);
+	if (ret)
+		return ret;
+
+	ret = sdw_transfer_unlocked(bus, &msg);
+	if (ret < 0)
+		return ret;
+
+	return buf;
+}
+EXPORT_SYMBOL(sdw_bread_no_pm_unlocked);
+
+int sdw_bwrite_no_pm_unlocked(struct sdw_bus *bus, u16 dev_num, u32 addr, u8 value)
+{
+	struct sdw_msg msg;
+	int ret;
+
+	ret = sdw_fill_msg(&msg, NULL, addr, 1, dev_num,
+			   SDW_MSG_FLAG_WRITE, &value);
+	if (ret)
+		return ret;
+
+	return sdw_transfer_unlocked(bus, &msg);
+}
+EXPORT_SYMBOL(sdw_bwrite_no_pm_unlocked);
 
 static int
 sdw_read_no_pm(struct sdw_slave *slave, u32 addr)

drivers/soundwire/bus.h

···
 	return sdw_write(slave, addr, tmp);
 }
 
+/* broadcast read/write for tests */
+int sdw_bread_no_pm_unlocked(struct sdw_bus *bus, u16 dev_num, u32 addr);
+int sdw_bwrite_no_pm_unlocked(struct sdw_bus *bus, u16 dev_num, u32 addr, u8 value);
+
 /*
  * At the moment we only track Master-initiated hw_reset.
  * Additional fields can be added as needed