usb: musb: start session in resume for host port

commit 7f88a5ac upstream.

Commit 17539f2f ("usb: musb: fix enumeration after resume") replaced
musb_start() in musb_resume() to not override softconnect bit, but it
doesn't restart the session for host port which was done in musb_start().
The session could be disabled in musb_suspend(), which leads the host
port doesn't stay in host mode.

So let's start the session specifically for host port in musb_resume().

Fixes: 17539f2f ("usb: musb: fix enumeration after resume")

Cc: stable@vger.kernel.org
Signed-off-by: Bin Liu <b-liu@ti.com>
Link: https://lore.kernel.org/r/20200525025049.3400-3-b-liu@ti.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/musb/musb_core.c

@@ -2737,6 +2737,13 @@ static int musb_resume(struct device *dev)
 	musb_enable_interrupts(musb);
 	musb_platform_enable(musb);
 
+	/* session might be disabled in suspend */
+	if (musb->port_mode == MUSB_HOST &&
+	    !(musb->ops->quirks & MUSB_PRESERVE_SESSION)) {
+		devctl |= MUSB_DEVCTL_SESSION;
+		musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);
+	}
+
 	spin_lock_irqsave(&musb->lock, flags);
 	error = musb_run_resume_work(musb);
 	if (error)