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usb: dwc3: workaround: unexpected transtion U3 -> RESUME

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In DWC3 versions < 2.50a configured without
Hibernation mode enabled, there will be an
extra link status change interrupt if device
detects host-initiated U3 exit.

In that case, core will generate an unnecessary
U3 -> RESUME transition which should be ignored
by the driver.

Signed-off-by: Felipe Balbi <balbi@ti.com>
This commit is contained in:
Felipe Balbi 2012-09-18 21:39:24 +03:00
parent 7ac6a593d5
commit 0b0cc1cd31
1 changed files with 28 additions and 0 deletions
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28
drivers/usb/dwc3/gadget.c
View file

@ -2317,6 +2317,34 @@ static void dwc3_gadget_linksts_change_interrupt(struct dwc3 *dwc,
unsigned int evtinfo)
{
enum dwc3_link_state next = evtinfo & DWC3_LINK_STATE_MASK;
unsigned int pwropt;
/*
* WORKAROUND: DWC3 < 2.50a have an issue when configured without
* Hibernation mode enabled which would show up when device detects
* host-initiated U3 exit.
*
* In that case, device will generate a Link State Change Interrupt
* from U3 to RESUME which is only necessary if Hibernation is
* configured in.
*
* There are no functional changes due to such spurious event and we
* just need to ignore it.
*
* Refers to:
*
* STAR#9000570034 RTL: SS Resume event generated in non-Hibernation
* operational mode
*/
pwropt = DWC3_GHWPARAMS1_EN_PWROPT(dwc->hwparams.hwparams1);
if ((dwc->revision < DWC3_REVISION_250A) &&
(pwropt != DWC3_GHWPARAMS1_EN_PWROPT_HIB)) {
if ((dwc->link_state == DWC3_LINK_STATE_U3) &&
(next == DWC3_LINK_STATE_RESUME)) {
dev_vdbg(dwc->dev, "ignoring transition U3 -> Resume\n");
return;
}
}
/*
* WORKAROUND: DWC3 Revisions <1.83a have an issue which, depending