usb, davinci: usb 2.0 problem on an am1808 based board

[Manjunathappa, Prakash]

Hi Heiko,

I do not know how putting delay helped MSC device detection.
Can you please check if MUSB is coming up in "b_idle" state(by
$cat /sys/devices/platform/musb-da8xx/musb-hdrc/mode)?
State should move to b_peripheral on connecting gadget cable.
If you connect MSC device via mini-A connector, state should change to "a_host".
OTG timer is responsible for above state changes, can you please check if below
changes are present?
diff --git a/drivers/usb/musb/da8xx.c b/drivers/usb/musb/da8xx.c index 4da7492..a1a692e 100644
--- a/drivers/usb/musb/da8xx.c
+++ b/drivers/usb/musb/da8xx.c
@@ -76,6 +76,7 @@
 #define DA8XX_INTR_TX_SHIFT    0
 #define DA8XX_INTR_TX_MASK     (DA8XX_USB_TX_EP_MASK << DA8XX_INTR_TX_SHIFT)

+#define A_WAIT_BCON_TIMEOUT     1100            /* in ms */
 #define DA8XX_MENTOR_CORE_OFFSET 0x400

 #define CFGCHIP2       IO_ADDRESS(DA8XX_SYSCFG0_BASE + DA8XX_CFGCHIP2_REG)
@@ -443,6 +444,7 @@ static int da8xx_musb_init(struct musb *musb)
                 rev, __raw_readl(CFGCHIP2),
                 musb_readb(reg_base, DA8XX_USB_CTRL_REG));

+       musb->a_wait_bcon = A_WAIT_BCON_TIMEOUT;
        musb->isr = da8xx_musb_interrupt;
        return 0;
 fail:

Thanks,
Prakash

On Thu, May 17, 2012 at 12:07:23, Heiko Schocher wrote:
> Hello,
> 
> Heiko Schocher wrote:
> > Hello,
> > 
> > a while ago (see discussion here:
> > http://comments.gmane.org/gmane.linux.usb.general/54505), I found this
> > "USB timing Bug" on an am1808 based board:
> > 
> > Heiko Schocher wrote:
> >> Hello Sergei,
> > [...]
> >> Sergei Shtylyov wrote:
> >>> Hello.
> >>>
> >>> On 11.11.2011 11:19, Felipe Balbi wrote:
> >>>
> >>>>> I try to bring up usb 2.0 support on an am1808 based
> >>>>> board and Linux version 3.1.0-rc10 and I am facing
> >>>>> some issues:
> > [...]
> >>>>>   But if I add in drivers/usb/musb/da8xx.c
> >>>>>    da8xx_musb_interrupt() a 10ms delay befor the
> >>>>>    "if (status&  (DA8XX_INTR_DRVVBUS<<  DA8XX_INTR_USB_SHIFT)) {"
> >>>>>    line usb works fine!
> >>>>>    It also works without this timeout if I change the
> >>>>>    "dev_dbg(musb->controller, "USB IRQ %08x\n", status);"
> >>>>>    to
> >>>>>    "printk(musb->controller, "USB IRQ %08x\n", status);"
> >>>>>
> >>>>>    ->  some timing issue, but I have no idea why!
> >>>>>       (Maybe you have an idea?)
> >>>> unfortunately I don't know any details about DaVinci.
> >>>    AM1808 is not exactly DaVinci, to be precise...
> >>>
> >>>> Sergei, are you able to help on this question ?
> >>>    Maybe. :-)
> >> I hope it ;-)
> > 
> > now I digged deeper and found this patch, which solves the
> > problem (without adding a 10 ms delay):
> > 
> > -----------------------------
> > diff --git a/drivers/usb/musb/da8xx.c b/drivers/usb/musb/da8xx.c
> > index d32aa4d..6a6b17b 100644
> > --- a/drivers/usb/musb/da8xx.c
> > +++ b/drivers/usb/musb/da8xx.c
> > @@ -297,6 +297,7 @@ static irqreturn_t da8xx_musb_interrupt(int irq, void *hci)
> >         unsigned long           flags;
> >         irqreturn_t             ret = IRQ_NONE;
> >         u32                     status;
> > +       int                     flag = 1;
> > 
> >         spin_lock_irqsave(&musb->lock, flags);
> > 
> > @@ -368,6 +363,7 @@ static irqreturn_t da8xx_musb_interrupt(int irq, void *hci)
> >                         musb->xceiv->default_a = 0;
> >                         musb->xceiv->state = OTG_STATE_B_IDLE;
> >                         portstate(musb->port1_status &= ~USB_PORT_STAT_POWER);
> > +                       flag = 0;
> >                 }
> > 
> >                 dev_dbg(musb->controller, "VBUS %s (%s)%s, devctl %02x\n",
> > @@ -378,7 +374,7 @@ static irqreturn_t da8xx_musb_interrupt(int irq, void *hci)
> >                 ret = IRQ_HANDLED;
> >         }
> > 
> > -       if (musb->int_tx || musb->int_rx || musb->int_usb)
> > +       if (flag && ((musb->int_tx || musb->int_rx || musb->int_usb)))
> >                 ret |= musb_interrupt(musb);
> > 
> >   eoi:
> > -----------------------------
> > 
> > If we get an DA8XX_INTR_DRVVBUS IRQ, in the else case
> > 
> > musb->xceiv->state = OTG_STATE_B_IDLE;
> > 
> > is set, but overwritten in the musb_interrupt() call, which results
> > in not starting the "Poll for ID change" timer ... as I am not an USB
> > expert, posting this intermediate result here, maybe someone have an
> > idea/explanation if this patch is the way to go, or what would be a
> > better solution?