On Thu, 9 Aug 2012 14:15:51 +0300 Felipe Balbi <ba...@ti.com> wrote:

> hehe, that's nasty. Please send a patch converting to a try count and a
> udelay_range(), or something.
> 

how's this?

Thanks,
NeilBrown


From: NeilBrown <ne...@suse.de>
Date: Mon, 13 Aug 2012 12:32:58 +1000
Subject: [PATCH] omap2430: don't loop indefinitely in interrupt.

When called during resume_irqs, omap2430_musb_set_vbus() is run with
interrupts disabled,  In that case 'jiffies' never changes so the loop
can loop forever.

So impose a maximum loop count and add an 'mdelay' to ensure we wait
a reasonable amount of time for bit to be cleared.

This fixes a hang on resume.

Signed-of-by: NeilBrown <ne...@suse.de>

diff --git a/drivers/usb/musb/omap2430.c b/drivers/usb/musb/omap2430.c
index c7785e8..8a93381 100644
--- a/drivers/usb/musb/omap2430.c
+++ b/drivers/usb/musb/omap2430.c
@@ -34,6 +34,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/pm_runtime.h>
 #include <linux/err.h>
+#include <linux/delay.h>
 
 #include "musb_core.h"
 #include "omap2430.h"
@@ -145,6 +146,7 @@ static void omap2430_musb_set_vbus(struct musb *musb, int 
is_on)
 
        if (is_on) {
                if (musb->xceiv->state == OTG_STATE_A_IDLE) {
+                       int loops = 100;
                        /* start the session */
                        devctl |= MUSB_DEVCTL_SESSION;
                        musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);
@@ -154,9 +156,11 @@ static void omap2430_musb_set_vbus(struct musb *musb, int 
is_on)
                         */
                        while (musb_readb(musb->mregs, MUSB_DEVCTL) & 0x80) {
 
+                               mdelay(5);
                                cpu_relax();
 
-                               if (time_after(jiffies, timeout)) {
+                               if (time_after(jiffies, timeout)
+                                   || loops-- <= 0) {
                                        dev_err(musb->controller,
                                        "configured as A device timeout");
                                        ret = -EINVAL;

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