mailbox: pcc: Use mbox_bind_client

Use generic mbox_bind_client() to bind omap mailbox channel to a client.

mbox_bind_client is identical to the replaced lines, except that it:
 - Does the operation under con_mutex which prevents possible races in
   removal path
 - Sets TXDONE_BY_ACK if pcc uses TXDONE_BY_POLL and the client knows
   when tx is done. TXDONE_BY_ACK is already set if there's no interrupt,
   so this is not applicable.
 - Calls chan->mbox->ops->startup. This is usecase for requesting irq:
   move the devm_request_irq into the startup callback and unregister it
   in the shutdown path.
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

drivers/mailbox/pcc.c

@@ -282,8 +282,7 @@ pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id)
 {
 	struct pcc_chan_info *pchan;
 	struct mbox_chan *chan;
-	struct device *dev;
-	unsigned long flags;
+	int rc;
 
 	if (subspace_id < 0 || subspace_id >= pcc_chan_count)
 		return ERR_PTR(-ENOENT);
@@ -294,32 +293,10 @@ pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id)
 		pr_err("Channel not found for idx: %d\n", subspace_id);
 		return ERR_PTR(-EBUSY);
 	}
-	dev = chan->mbox->dev;
-
-	spin_lock_irqsave(&chan->lock, flags);
-	chan->msg_free = 0;
-	chan->msg_count = 0;
-	chan->active_req = NULL;
-	chan->cl = cl;
-	init_completion(&chan->tx_complete);
-
-	if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
-		chan->txdone_method = TXDONE_BY_ACK;
 
-	spin_unlock_irqrestore(&chan->lock, flags);
-
-	if (pchan->plat_irq > 0) {
-		int rc;
-
-		rc = devm_request_irq(dev, pchan->plat_irq, pcc_mbox_irq, 0,
-				      MBOX_IRQ_NAME, chan);
-		if (unlikely(rc)) {
-			dev_err(dev, "failed to register PCC interrupt %d\n",
-				pchan->plat_irq);
-			pcc_mbox_free_channel(&pchan->chan);
+	rc = mbox_bind_client(chan, cl);
+	if (rc)
 		return ERR_PTR(rc);
-		}
-	}
 
 	return &pchan->chan;
 }
@@ -333,23 +310,12 @@ EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
  */
 void pcc_mbox_free_channel(struct pcc_mbox_chan *pchan)
 {
-	struct pcc_chan_info *pchan_info = to_pcc_chan_info(pchan);
 	struct mbox_chan *chan = pchan->mchan;
-	unsigned long flags;
 
 	if (!chan || !chan->cl)
 		return;
 
-	if (pchan_info->plat_irq > 0)
-		devm_free_irq(chan->mbox->dev, pchan_info->plat_irq, chan);
-
-	spin_lock_irqsave(&chan->lock, flags);
-	chan->cl = NULL;
-	chan->active_req = NULL;
-	if (chan->txdone_method == TXDONE_BY_ACK)
-		chan->txdone_method = TXDONE_BY_POLL;
-
-	spin_unlock_irqrestore(&chan->lock, flags);
+	mbox_free_channel(chan);
 }
 EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
 
@@ -377,8 +343,48 @@ static int pcc_send_data(struct mbox_chan *chan, void *data)
 	return pcc_chan_reg_read_modify_write(&pchan->db);
 }
 
+/**
+ * pcc_startup - Called from Mailbox Controller code. Used here
+ *		to request the interrupt.
+ * @chan: Pointer to Mailbox channel to startup.
+ *
+ * Return: Err if something failed else 0 for success.
+ */
+static int pcc_startup(struct mbox_chan *chan)
+{
+	struct pcc_chan_info *pchan = chan->con_priv;
+	int rc;
+
+	if (pchan->plat_irq > 0) {
+		rc = devm_request_irq(chan->mbox->dev, pchan->plat_irq, pcc_mbox_irq, 0,
+				      MBOX_IRQ_NAME, chan);
+		if (unlikely(rc)) {
+			dev_err(chan->mbox->dev, "failed to register PCC interrupt %d\n",
+				pchan->plat_irq);
+			return rc;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * pcc_shutdown - Called from Mailbox Controller code. Used here
+ *		to free the interrupt.
+ * @chan: Pointer to Mailbox channel to shutdown.
+ */
+static void pcc_shutdown(struct mbox_chan *chan)
+{
+	struct pcc_chan_info *pchan = chan->con_priv;
+
+	if (pchan->plat_irq > 0)
+		devm_free_irq(chan->mbox->dev, pchan->plat_irq, chan);
+}
+
 static const struct mbox_chan_ops pcc_chan_ops = {
 	.send_data = pcc_send_data,
+	.startup = pcc_startup,
+	.shutdown = pcc_shutdown,
 };
 
 /**