A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-13 08:07:32 -04:00
Code Issues Projects Releases Packages Wiki Activity

usb: dwc3: Handle race between composition switch and cable disconnect

Browse source 
The current implementation of handling run/~stop of DCTL based
on state of VBUS or the pullup call from the udc core can
result in a below race condition where the run/~stop is cleared
twice leading to an invalid state of controller.

	Thread -1			Thread-2
	vbus_session (1)

	   spin_lock
	   no run_stop(1) call		pullup(1)
	   spin_unlock			  softconnect = 1
					  vbus_active checked

	vbus_session (0)
	   spin_lock
	   run_stop(0) called
	   spin_unlock

Prevent this by ensuring a proper state transitions and clear
run/~stop only when when there is a transition from ACTIVE
and there is an pullup(0) event or vbus_session(0) call.

Change-Id: I03c4acfc2c6697e02c510d079c7d48d9a82bb322
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>
Signed-off-by: Pratham Pratap <prathampratap@codeaurora.org>
This commit is contained in:
Sriharsha Allenki 2020-06-23 15:27:10 +05:30 • committed by Pratham Pratap
commit 592dc3b133
2 changed files with 78 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

8
drivers/usb/dwc3/core.h
View file

@ -850,6 +850,13 @@ enum dwc3_link_state {
DWC3_LINK_STATE_MASK = 0x0f,
};
enum gadget_state {
DWC3_GADGET_INACTIVE,
DWC3_GADGET_SOFT_CONN,
DWC3_GADGET_CABLE_CONN,
DWC3_GADGET_ACTIVE,
};
/* TRB Length, PCM and Status */
#define DWC3_TRB_SIZE_MASK (0x00ffffff)
#define DWC3_TRB_SIZE_LENGTH(n) ((n) & DWC3_TRB_SIZE_MASK)
@ -1382,6 +1389,7 @@ struct dwc3 {
unsigned int irq_event_count[MAX_INTR_STATS];
unsigned int irq_dbg_index;
enum gadget_state gadget_state;
/* Indicate if the gadget was powered by the otg driver */
unsigned int vbus_active:1;
/* Indicate if software connect was issued by the usb_gadget_driver */

86
drivers/usb/dwc3/gadget.c
View file

@ -2309,6 +2309,71 @@ static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend)
return 0;
}
static int dwc3_gadget_run_stop_util(struct dwc3 *dwc)
{
int ret = 0;
dev_dbg(dwc->dev, "%s: enter: %d\n", __func__, dwc->gadget_state);
switch (dwc->gadget_state) {
case DWC3_GADGET_INACTIVE:
if (dwc->vbus_active && dwc->softconnect) {
ret = dwc3_gadget_run_stop(dwc, true, false);
dwc->gadget_state = DWC3_GADGET_ACTIVE;
break;
}
if (dwc->vbus_active) {
dwc->gadget_state = DWC3_GADGET_CABLE_CONN;
break;
}
if (dwc->softconnect) {
dwc->gadget_state = DWC3_GADGET_SOFT_CONN;
break;
}
case DWC3_GADGET_SOFT_CONN:
if (!dwc->softconnect) {
dwc->gadget_state = DWC3_GADGET_INACTIVE;
break;
}
if (dwc->vbus_active) {
ret = dwc3_gadget_run_stop(dwc, true, false);
dwc->gadget_state = DWC3_GADGET_ACTIVE;
}
break;
case DWC3_GADGET_CABLE_CONN:
if (!dwc->vbus_active) {
dwc->gadget_state = DWC3_GADGET_INACTIVE;
break;
}
if (dwc->softconnect) {
ret = dwc3_gadget_run_stop(dwc, true, false);
dwc->gadget_state = DWC3_GADGET_ACTIVE;
}
break;
case DWC3_GADGET_ACTIVE:
if (!dwc->vbus_active) {
dwc->gadget_state = DWC3_GADGET_SOFT_CONN;
ret = dwc3_gadget_run_stop(dwc, false, false);
break;
}
if (!dwc->softconnect) {
dwc->gadget_state = DWC3_GADGET_CABLE_CONN;
ret = dwc3_gadget_run_stop(dwc, false, false);
break;
}
break;
default:
dev_err(dwc->dev, "Invalid state\n");
}
dev_dbg(dwc->dev, "%s: exit: %d\n", __func__, dwc->gadget_state);
return ret;
}
static int dwc3_gadget_vbus_draw(struct usb_gadget *g, unsigned int mA)
{
struct dwc3 *dwc = gadget_to_dwc(g);
@ -2328,6 +2393,7 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
ktime_t diff;
is_on = !!is_on;
spin_lock_irqsave(&dwc->lock, flags);
dwc->softconnect = is_on;
if (((dwc->dr_mode > USB_DR_MODE_HOST) && !dwc->vbus_active)
@ -2337,9 +2403,11 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
* Need to wait for vbus_session(on) from otg driver or to
* the udc_start.
*/
spin_unlock_irqrestore(&dwc->lock, flags);
dbg_event(0xFF, "WaitPullup", 0);
return 0;
}
spin_unlock_irqrestore(&dwc->lock, flags);
pm_runtime_get_sync(dwc->dev);
dbg_event(0xFF, "Pullup gsync",
@ -2393,7 +2461,7 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
dwc->b_suspend = false;
dwc3_notify_event(dwc, DWC3_CONTROLLER_NOTIFY_OTG_EVENT, 0);
ret = dwc3_gadget_run_stop(dwc, is_on, false);
ret = dwc3_gadget_run_stop_util(dwc);
spin_unlock_irqrestore(&dwc->lock, flags);
if (!is_on && ret == -ETIMEDOUT) {
/*
@ -2514,21 +2582,7 @@ static int dwc3_gadget_vbus_session(struct usb_gadget *_gadget, int is_active)
/* Mark that the vbus was powered */
dwc->vbus_active = is_active;
/*
* Check if upper level usb_gadget_driver was already registered with
* this udc controller driver (if dwc3_gadget_start was called)
*/
if (dwc->gadget_driver && dwc->softconnect) {
if (dwc->vbus_active) {
/*
* Both vbus was activated by otg and pullup was
* signaled by the gadget driver.
*/
ret = dwc3_gadget_run_stop(dwc, 1, false);
} else {
ret = dwc3_gadget_run_stop(dwc, 0, false);
}
}
ret = dwc3_gadget_run_stop_util(dwc);
/*
* Clearing run/stop bit might occur before disconnect event is seen.