mailbox: imx: get RR/TR registers num from Parameter register

i.MX8ULP, i.MX93 MU has a Parameter register encoded as below:
BIT: 15 --- 8 | 7 --- 0
      RR_NUM    TR_NUM

So to make driver easy to support more variants, get the RR/TR
registers number from Parameter register.

The patch only adds support the specific MU, such as ELE MU.
For generic MU, not add support for number larger than 4.

Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>

drivers/mailbox/imx-mailbox.c

@@ -4,6 +4,7 @@
  * Copyright 2022 NXP, Peng Fan <peng.fan@nxp.com>
  */
 
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/firmware/imx/ipc.h>
 #include <linux/firmware/imx/s4.h>
@@ -29,7 +30,9 @@
 #define IMX_MU_S4_CHANS		2
 #define IMX_MU_CHAN_NAME_SIZE	20
 
-#define IMX_MU_NUM_RR		4
+#define IMX_MU_V2_PAR_OFF	0x4
+#define IMX_MU_V2_TR_MASK	GENMASK(7, 0)
+#define IMX_MU_V2_RR_MASK	GENMASK(15, 8)
 
 #define IMX_MU_SECO_TX_TOUT (msecs_to_jiffies(3000))
 #define IMX_MU_SECO_RX_TOUT (msecs_to_jiffies(3000))
@@ -93,10 +96,11 @@ struct imx_mu_priv {
 	struct clk		*clk;
 	int			irq[IMX_MU_CHANS];
 	bool			suspend;
-
-	u32 xcr[IMX_MU_xCR_MAX];
-
 	bool			side_b;
+
+	u32			xcr[IMX_MU_xCR_MAX];
+	u32			num_tr;
+	u32			num_rr;
 };
 
 enum imx_mu_type {
@@ -264,18 +268,17 @@ static int imx_mu_generic_rxdb(struct imx_mu_priv *priv,
 static int imx_mu_specific_tx(struct imx_mu_priv *priv, struct imx_mu_con_priv *cp, void *data)
 {
 	u32 *arg = data;
+	u32 num_tr = priv->num_tr;
 	int i, ret;
 	u32 xsr;
-	u32 size, max_size, num_tr;
+	u32 size, max_size;
 
 	if (priv->dcfg->type & IMX_MU_V2_S4) {
 		size = ((struct imx_s4_rpc_msg_max *)data)->hdr.size;
 		max_size = sizeof(struct imx_s4_rpc_msg_max);
-		num_tr = 8;
 	} else {
 		size = ((struct imx_sc_rpc_msg_max *)data)->hdr.size;
 		max_size = sizeof(struct imx_sc_rpc_msg_max);
-		num_tr = 4;
 	}
 
 	switch (cp->type) {
@@ -324,6 +327,7 @@ static int imx_mu_specific_rx(struct imx_mu_priv *priv, struct imx_mu_con_priv *
 	int i, ret;
 	u32 xsr;
 	u32 size, max_size;
+	u32 num_rr = priv->num_rr;
 
 	data = (u32 *)priv->msg;
 
@@ -345,13 +349,13 @@ static int imx_mu_specific_rx(struct imx_mu_priv *priv, struct imx_mu_con_priv *
 
 	for (i = 1; i < size; i++) {
 		ret = readl_poll_timeout(priv->base + priv->dcfg->xSR[IMX_MU_RSR], xsr,
-					 xsr & IMX_MU_xSR_RFn(priv->dcfg->type, i % 4), 0,
+					 xsr & IMX_MU_xSR_RFn(priv->dcfg->type, i % num_rr), 0,
 					 5 * USEC_PER_SEC);
 		if (ret) {
 			dev_err(priv->dev, "timeout read idx %d\n", i);
 			return ret;
 		}
-		*data++ = imx_mu_read(priv, priv->dcfg->xRR + (i % 4) * 4);
+		*data++ = imx_mu_read(priv, priv->dcfg->xRR + (i % num_rr) * 4);
 	}
 
 	imx_mu_xcr_rmw(priv, IMX_MU_RCR, IMX_MU_xCR_RIEn(priv->dcfg->type, 0), 0);
@@ -737,11 +741,30 @@ static struct mbox_chan *imx_mu_seco_xlate(struct mbox_controller *mbox,
 	return imx_mu_xlate(mbox, sp);
 }
 
+static void imx_mu_get_tr_rr(struct imx_mu_priv *priv)
+{
+	u32 val;
+
+	if (priv->dcfg->type & IMX_MU_V2) {
+		val = imx_mu_read(priv, IMX_MU_V2_PAR_OFF);
+		priv->num_tr = FIELD_GET(IMX_MU_V2_TR_MASK, val);
+		priv->num_rr = FIELD_GET(IMX_MU_V2_RR_MASK, val);
+	} else {
+		priv->num_tr = 4;
+		priv->num_rr = 4;
+	}
+}
+
 static int imx_mu_init_generic(struct imx_mu_priv *priv)
 {
 	unsigned int i;
 	unsigned int val;
 
+	if (priv->num_rr > 4 || priv->num_tr > 4) {
+		WARN_ONCE(true, "%s not support TR/RR larger than 4\n", __func__);
+		return -EOPNOTSUPP;
+	}
+
 	for (i = 0; i < IMX_MU_CHANS; i++) {
 		struct imx_mu_con_priv *cp = &priv->con_priv[i];
 
@@ -768,8 +791,8 @@ static int imx_mu_init_generic(struct imx_mu_priv *priv)
 	imx_mu_write(priv, val, priv->dcfg->xSR[IMX_MU_GSR]);
 
 	/* Clear any pending RSR */
-	for (i = 0; i < IMX_MU_NUM_RR; i++)
-		imx_mu_read(priv, priv->dcfg->xRR + (i % 4) * 4);
+	for (i = 0; i < priv->num_rr; i++)
+		imx_mu_read(priv, priv->dcfg->xRR + i * 4);
 
 	return 0;
 }
@@ -874,6 +897,8 @@ static int imx_mu_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	imx_mu_get_tr_rr(priv);
+
 	priv->side_b = of_property_read_bool(np, "fsl,mu-side-b");
 
 	ret = priv->dcfg->init(priv);