Hi Oleksij,

two more nitpickings fro my side.

On 08/02/2018 10:23 AM, Oleksij Rempel wrote:

The i.MX Messaging Unit is a two side block which allows applications
implement communication over this sides.

The MU includes the following features:
- Messaging control by interrupts or by polling
- Four general-purpose interrupt requests reflected to the other side
- Three general-purpose flags reflected to the other side
- Four receive registers with maskable interrupt
- Four transmit registers with maskable interrupt

Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>

[snip]

+static irqreturn_t imx_mu_isr(int irq, void *p)
+{
+	struct mbox_chan *chan = p;
+	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
+	struct imx_mu_con_priv *cp = chan->con_priv;
+	u32 val, ctrl, dat;
+
+	ctrl = imx_mu_read(priv, IMX_MU_xCR);
+	val = imx_mu_read(priv, IMX_MU_xSR);
+
+	switch (cp->type) {
+	case IMX_MU_TYPE_TX:
+		val &= IMX_MU_xSR_TEn(cp->idx) &
+			(ctrl & IMX_MU_xCR_TIEn(cp->idx));
+		break;
+	case IMX_MU_TYPE_RX:
+		val &= IMX_MU_xSR_RFn(cp->idx) &
+			(ctrl & IMX_MU_xCR_RIEn(cp->idx));
+		break;
+	case IMX_MU_TYPE_RXDB:
+		val &= IMX_MU_xSR_GIPn(cp->idx) &
+			(ctrl & IMX_MU_xCR_GIEn(cp->idx));
+		break;
+	default:
+		break;
+	}
+
+	if (!val) {
+		return IRQ_NONE;
+	} else if (val == IMX_MU_xSR_TEn(cp->idx)) {

Please drop the 'else' branch above.

Here you can either just start from a new 'if', or all together drop 'if (!val)'
and return IRQ_NONE at the end of the if-else construction.

+		imx_mu_xcr_rmw(priv, 0, IMX_MU_xCR_TIEn(cp->idx));
+		mbox_chan_txdone(chan, 0);
+	} else if (val == IMX_MU_xSR_RFn(cp->idx)) {
+		dat = imx_mu_read(priv, IMX_MU_xRRn(cp->idx));
+		mbox_chan_received_data(chan, (void *)&dat);
+	} else if (val == IMX_MU_xSR_GIPn(cp->idx)) {
+		imx_mu_write(priv, IMX_MU_xSR_GIPn(cp->idx), IMX_MU_xSR);
+		mbox_chan_received_data(chan, NULL);
+	} else {
+		dev_warn_ratelimited(priv->dev, "Not handled interrupt\n");
+		return IRQ_NONE;
+	}
+
+	return IRQ_HANDLED;
+}

[snip]

+	for (i = 0; i < IMX_MU_CHANS; i++) {
+		struct imx_mu_con_priv *cp = &priv->con_priv[i];
+
+		cp->idx = i % 4;
+		cp->type = (i - cp->idx) >> 2;

cp->type = i >> 2;

+		cp->chan = &priv->mbox_chans[i];
+		priv->mbox_chans[i].con_priv = cp;
+		snprintf(cp->irq_desc, sizeof(cp->irq_desc),
+			 "imx_mu_chan[%i-%i]", cp->type, cp->idx);
+	}
+
+	priv->side_b = of_property_read_bool(np, "fsl,mu-side-b");
+
+	spin_lock_init(&priv->xcr_lock);
+
+	priv->mbox.dev = dev;
+	priv->mbox.ops = &imx_mu_ops;
+	priv->mbox.chans = priv->mbox_chans;
+	priv->mbox.num_chans = IMX_MU_CHANS;
+	priv->mbox.of_xlate = imx_mu_xlate;
+	priv->mbox.txdone_irq = true;
+
+	platform_set_drvdata(pdev, priv);
+
+	imx_mu_init_generic(priv);
+
+	return mbox_controller_register(&priv->mbox);
+}

--
Best wishes,
Vladimir