[U-Boot] [PATCH] MUSB timeout broken

Orjan Friberg of at flatfrog.com
Mon Jul 4 16:37:34 CEST 2011


The following construct (musb_hcd.c, usb_lowlevel_init)

    timeout = musb_cfg.timeout;
         while (timeout--)
                 if (readb(&musbr->devctl) & MUSB_DEVCTL_HM)
                         break;

will leave timeout == -1 when the timeout is reached, hence the timeout 
detecting code that follows will not trigger:

         /* if musb core is not in host mode, then return */
         if (!timeout)
                 return -1;


Without the patch below, doing a 'usb reset' without a device connected 
makes it impossible to discover connected devices later.  I have not 
investigated why this happens since the timeout logic was broken (and 
correcting that fixed the issue at hand).

Changed to pre-decrement since I assume the timeout value is not *that* 
exact.

Thanks,
Orjan

diff --git a/drivers/usb/musb/musb_hcd.c b/drivers/usb/musb/musb_hcd.c
index 974bb31..adcf7f7 100644
--- a/drivers/usb/musb/musb_hcd.c
+++ b/drivers/usb/musb/musb_hcd.c
@@ -1114,7 +1114,7 @@ int usb_lowlevel_init(void)
          * should be a usb device connected.
          */
         timeout = musb_cfg.timeout;
-       while (timeout--)
+       while (--timeout)
                 if (readb(&musbr->devctl) & MUSB_DEVCTL_HM)
                         break;




-- 
Orjan Friberg
FlatFrog Laboratories AB


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