slimbus: messaging: add slim_alloc/free_txn_tid()

This patch adds slim_alloc_txn_tid() and slim_free_txn_tid() api
to allow controllers like ngd to allocate tids for user specific
commands. This also cleans up the existing code to use single place
for tid allocations and free.

This patch also make the tid allocation cyclic one, its very useful
to track the transactions back during debug.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 52 insertions, 22 deletions

diff --git a/drivers/slimbus/messaging.c b/drivers/slimbus/messaging.c
index e3605ed1c459..d5879142dbef 100644
--- a/drivers/slimbus/messaging.c
+++ b/drivers/slimbus/messaging.c
@@ -29,22 +29,19 @@ void slim_msg_response(struct slim_controller *ctrl, u8 *reply, u8 tid, u8 len)
 
 	spin_lock_irqsave(&ctrl->txn_lock, flags);
 	txn = idr_find(&ctrl->tid_idr, tid);
-	if (txn == NULL) {
-		spin_unlock_irqrestore(&ctrl->txn_lock, flags);
+	spin_unlock_irqrestore(&ctrl->txn_lock, flags);
+
+	if (txn == NULL)
 		return;
-	}
 
 	msg = txn->msg;
 	if (msg == NULL || msg->rbuf == NULL) {
 		dev_err(ctrl->dev, "Got response to invalid TID:%d, len:%d\n",
 				tid, len);
-		spin_unlock_irqrestore(&ctrl->txn_lock, flags);
 		return;
 	}
 
-	idr_remove(&ctrl->tid_idr, tid);
-	spin_unlock_irqrestore(&ctrl->txn_lock, flags);
-
+	slim_free_txn_tid(ctrl, txn);
 	memcpy(msg->rbuf, reply, len);
 	if (txn->comp)
 		complete(txn->comp);
@@ -56,6 +53,48 @@ void slim_msg_response(struct slim_controller *ctrl, u8 *reply, u8 tid, u8 len)
 EXPORT_SYMBOL_GPL(slim_msg_response);
 
 /**
+ * slim_alloc_txn_tid() - Allocate a tid to txn
+ *
+ * @ctrl: Controller handle
+ * @txn: transaction to be allocated with tid.
+ *
+ * Return: zero on success with valid txn->tid and error code on failures.
+ */
+int slim_alloc_txn_tid(struct slim_controller *ctrl, struct slim_msg_txn *txn)
+{
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&ctrl->txn_lock, flags);
+	ret = idr_alloc_cyclic(&ctrl->tid_idr, txn, 0,
+				SLIM_MAX_TIDS, GFP_ATOMIC);
+	if (ret < 0) {
+		spin_unlock_irqrestore(&ctrl->txn_lock, flags);
+		return ret;
+	}
+	txn->tid = ret;
+	spin_unlock_irqrestore(&ctrl->txn_lock, flags);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(slim_alloc_txn_tid);
+
+/**
+ * slim_free_txn_tid() - Freee tid of txn
+ *
+ * @ctrl: Controller handle
+ * @txn: transaction whose tid should be freed
+ */
+void slim_free_txn_tid(struct slim_controller *ctrl, struct slim_msg_txn *txn)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&ctrl->txn_lock, flags);
+	idr_remove(&ctrl->tid_idr, txn->tid);
+	spin_unlock_irqrestore(&ctrl->txn_lock, flags);
+}
+EXPORT_SYMBOL_GPL(slim_free_txn_tid);
+
+/**
  * slim_do_transfer() - Process a SLIMbus-messaging transaction
  *
  * @ctrl: Controller handle
@@ -72,8 +111,7 @@ int slim_do_transfer(struct slim_controller *ctrl, struct slim_msg_txn *txn)
 {
 	DECLARE_COMPLETION_ONSTACK(done);
 	bool need_tid = false, clk_pause_msg = false;
-	unsigned long flags;
-	int ret, tid, timeout;
+	int ret, timeout;
 
 	/*
 	 * do not vote for runtime-PM if the transactions are part of clock
@@ -97,34 +135,26 @@ int slim_do_transfer(struct slim_controller *ctrl, struct slim_msg_txn *txn)
 	need_tid = slim_tid_txn(txn->mt, txn->mc);
 
 	if (need_tid) {
-		spin_lock_irqsave(&ctrl->txn_lock, flags);
-		tid = idr_alloc(&ctrl->tid_idr, txn, 0,
-				SLIM_MAX_TIDS, GFP_ATOMIC);
-		txn->tid = tid;
+		ret = slim_alloc_txn_tid(ctrl, txn);
+		if (ret)
+			return ret;
 
 		if (!txn->msg->comp)
 			txn->comp = &done;
 		else
 			txn->comp = txn->comp;
-
-		spin_unlock_irqrestore(&ctrl->txn_lock, flags);
-
-		if (tid < 0)
-			return tid;
 	}
 
 	ret = ctrl->xfer_msg(ctrl, txn);
 
-	if (ret && need_tid && !txn->msg->comp) {
+	if (!ret && need_tid && !txn->msg->comp) {
 		unsigned long ms = txn->rl + HZ;
 
 		timeout = wait_for_completion_timeout(txn->comp,
 						      msecs_to_jiffies(ms));
 		if (!timeout) {
 			ret = -ETIMEDOUT;
-			spin_lock_irqsave(&ctrl->txn_lock, flags);
-			idr_remove(&ctrl->tid_idr, tid);
-			spin_unlock_irqrestore(&ctrl->txn_lock, flags);
+			slim_free_txn_tid(ctrl, txn);
 		}
 	}