Re: resetting USB HC at kernel boot.

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On Thu, Sep 2, 2010 at 9:44 PM, Prabhu Chawandi
<prabhu.chavandi@xxxxxxxxx> wrote:
> Hi,
>
>  I  want to know how the HC is reset @ the boot of the kernel.

perhaps u can look here:

http://www.mail-archive.com/u-boot@xxxxxxxxxxxxx/msg34219.html

Searching the text for "HC reset" reveal its occurrence in several places.

And the kernel's version of the same file, drivers/usb/host/ohci-hcd.c
has some info too:

        /* HC Reset requires max 10 us delay */
        ohci_writel (ohci, OHCI_HCR,  &ohci->regs->cmdstatus);
        val = 30;       /* ... allow extra time */
        while ((ohci_readl (ohci, &ohci->regs->cmdstatus) & OHCI_HCR) != 0) {
                if (--val == 0) {
                        spin_unlock_irq (&ohci->lock);
                        ohci_err (ohci, "USB HC reset timed out!\n");
                        return -1;
                }
                udelay (1);
        }


>
> Thanks & Reagrs,
> Prabhu
>
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>



-- 
Regards,
Peter Teoh

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