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 <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Link: https://lore.kernel.org/r/20200908134521.6781-7-yung-chuan.liao@linux.intel.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/soundwire/bus.c

@@ -255,6 +255,21 @@ static int sdw_reset_page(struct sdw_bus *bus, u16 dev_num)
 	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
@@ -266,13 +281,7 @@ int sdw_transfer(struct sdw_bus *bus, struct sdw_msg *msg)
 
 	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);
 
@@ -428,6 +437,39 @@ sdw_bwrite_no_pm(struct sdw_bus *bus, u16 dev_num, u32 addr, u8 value)
 	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

@@ -168,6 +168,10 @@ sdw_update(struct sdw_slave *slave, u32 addr, u8 mask, u8 val)
 	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