mailbox: imx: fix wakeup failure from freeze mode

commit 892cb52 upstream.

Since IRQF_NO_SUSPEND used for imx mailbox driver, that means this irq
can't be used for wakeup source so that can't wakeup from freeze mode.
Add pm_system_wakeup() to wakeup from freeze mode.

Fixes: b7b2796("mailbox: imx: ONLY IPC MU needs IRQF_NO_SUSPEND flag")
Reviewed-by: Jacky Bai <ping.bai@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/mailbox/imx-mailbox.c

@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/suspend.h>
 #include <linux/slab.h>
 
 #define IMX_MU_xSR_GIPn(x)	BIT(28 + (3 - (x)))
@@ -66,6 +67,7 @@ struct imx_mu_priv {
 	const struct imx_mu_dcfg	*dcfg;
 	struct clk		*clk;
 	int			irq;
+	bool			suspend;
 
 	u32 xcr;
 
@@ -277,6 +279,9 @@ static irqreturn_t imx_mu_isr(int irq, void *p)
 		return IRQ_NONE;
 	}
 
+	if (priv->suspend)
+		pm_system_wakeup();
+
 	return IRQ_HANDLED;
 }
 
@@ -326,6 +331,8 @@ static int imx_mu_startup(struct mbox_chan *chan)
 		break;
 	}
 
+	priv->suspend = true;
+
 	return 0;
 }
 
@@ -543,6 +550,8 @@ static int imx_mu_probe(struct platform_device *pdev)
 
 	clk_disable_unprepare(priv->clk);
 
+	priv->suspend = false;
+
 	return 0;
 
 disable_runtime_pm: