firmware: imx-scu: Support one TX and one RX

Current imx-scu requires four TX and four RX to communicate with
SCU. This is low efficient and causes lots of mailbox interrupts.

With imx-mailbox driver could support one TX to use all four transmit
registers and one RX to use all four receive registers, imx-scu
could use one TX and one RX.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Author: MrVan

drivers/firmware/imx/imx-scu.c

@@ -38,6 +38,7 @@ struct imx_sc_ipc {
 	struct device *dev;
 	struct mutex lock;
 	struct completion done;
+	bool fast_ipc;
 
 	/* temporarily store the SCU msg */
 	u32 *msg;
@@ -115,13 +116,27 @@ static void imx_scu_rx_callback(struct mbox_client *c, void *msg)
 	struct imx_sc_ipc *sc_ipc = sc_chan->sc_ipc;
 	struct imx_sc_rpc_msg *hdr;
 	u32 *data = msg;
+	int i;
 
 	if (!sc_ipc->msg) {
 		dev_warn(sc_ipc->dev, "unexpected rx idx %d 0x%08x, ignore!\n",
 				sc_chan->idx, *data);
 		return;
 	}
 
+	if (sc_ipc->fast_ipc) {
+		hdr = msg;
+		sc_ipc->rx_size = hdr->size;
+		sc_ipc->msg[0] = *data++;
+
+		for (i = 1; i < sc_ipc->rx_size; i++)
+			sc_ipc->msg[i] = *data++;
+
+		complete(&sc_ipc->done);
+
+		return;
+	}
+
 	if (sc_chan->idx == 0) {
 		hdr = msg;
 		sc_ipc->rx_size = hdr->size;
@@ -147,6 +162,7 @@ static int imx_scu_ipc_write(struct imx_sc_ipc *sc_ipc, void *msg)
 	struct imx_sc_chan *sc_chan;
 	u32 *data = msg;
 	int ret;
+	int size;
 	int i;
 
 	/* Check size */
@@ -156,7 +172,8 @@ static int imx_scu_ipc_write(struct imx_sc_ipc *sc_ipc, void *msg)
 	dev_dbg(sc_ipc->dev, "RPC SVC %u FUNC %u SIZE %u\n", hdr->svc,
 		hdr->func, hdr->size);
 
-	for (i = 0; i < hdr->size; i++) {
+	size = sc_ipc->fast_ipc ? 1 : hdr->size;
+	for (i = 0; i < size; i++) {
 		sc_chan = &sc_ipc->chans[i % 4];
 
 		/*
@@ -168,8 +185,10 @@ static int imx_scu_ipc_write(struct imx_sc_ipc *sc_ipc, void *msg)
 		 * Wait for tx_done before every send to ensure that no
 		 * queueing happens at the mailbox channel level.
 		 */
-		wait_for_completion(&sc_chan->tx_done);
-		reinit_completion(&sc_chan->tx_done);
+		if (!sc_ipc->fast_ipc) {
+			wait_for_completion(&sc_chan->tx_done);
+			reinit_completion(&sc_chan->tx_done);
+		}
 
 		ret = mbox_send_message(sc_chan->ch, &data[i]);
 		if (ret < 0)
@@ -246,18 +265,29 @@ static int imx_scu_probe(struct platform_device *pdev)
 	struct imx_sc_chan *sc_chan;
 	struct mbox_client *cl;
 	char *chan_name;
+	struct of_phandle_args args;
+	int num_channel;
 	int ret;
 	int i;
 
 	sc_ipc = devm_kzalloc(dev, sizeof(*sc_ipc), GFP_KERNEL);
 	if (!sc_ipc)
 		return -ENOMEM;
 
-	for (i = 0; i < SCU_MU_CHAN_NUM; i++) {
-		if (i < 4)
+	ret = of_parse_phandle_with_args(pdev->dev.of_node, "mboxes",
+					 "#mbox-cells", 0, &args);
+	if (ret)
+		return ret;
+
+	sc_ipc->fast_ipc = of_device_is_compatible(args.np, "fsl,imx8-mu-scu");
+
+	num_channel = sc_ipc->fast_ipc ? 2 : SCU_MU_CHAN_NUM;
+	for (i = 0; i < num_channel; i++) {
+		if (i < num_channel / 2)
 			chan_name = kasprintf(GFP_KERNEL, "tx%d", i);
 		else
-			chan_name = kasprintf(GFP_KERNEL, "rx%d", i - 4);
+			chan_name = kasprintf(GFP_KERNEL, "rx%d",
+					      i - num_channel / 2);
 
 		if (!chan_name)
 			return -ENOMEM;
@@ -269,13 +299,15 @@ static int imx_scu_probe(struct platform_device *pdev)
 		cl->knows_txdone = true;
 		cl->rx_callback = imx_scu_rx_callback;
 
-		/* Initial tx_done completion as "done" */
-		cl->tx_done = imx_scu_tx_done;
-		init_completion(&sc_chan->tx_done);
-		complete(&sc_chan->tx_done);
+		if (!sc_ipc->fast_ipc) {
+			/* Initial tx_done completion as "done" */
+			cl->tx_done = imx_scu_tx_done;
+			init_completion(&sc_chan->tx_done);
+			complete(&sc_chan->tx_done);
+		}
 
 		sc_chan->sc_ipc = sc_ipc;
-		sc_chan->idx = i % 4;
+		sc_chan->idx = i % (num_channel / 2);
 		sc_chan->ch = mbox_request_channel_byname(cl, chan_name);
 		if (IS_ERR(sc_chan->ch)) {
 			ret = PTR_ERR(sc_chan->ch);