This is a note to let you know that I've just added the patch titled
usb: chipidea: udc: don't do hardware access if gadget has stopped
to my usb git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git in the usb-linus branch.
The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.
If you have any questions about this process, please let me know.
From cbe85c88ce80fb92956a0793518d415864dcead8 Mon Sep 17 00:00:00 2001
From: Peter Chen peter.chen@nxp.com Date: Tue, 20 Aug 2019 02:07:58 +0000 Subject: usb: chipidea: udc: don't do hardware access if gadget has stopped
After _gadget_stop_activity is executed, we can consider the hardware operation for gadget has finished, and the udc can be stopped and enter low power mode. So, any later hardware operations (from usb_ep_ops APIs or usb_gadget_ops APIs) should be considered invalid, any deinitializatons has been covered at _gadget_stop_activity.
I meet this problem when I plug out usb cable from PC using mass_storage gadget, my callstack like: vbus interrupt->.vbus_session-> composite_disconnect ->pm_runtime_put_sync(&_gadget->dev), the composite_disconnect will call fsg_disable, but fsg_disable calls usb_ep_disable using async way, there are register accesses for usb_ep_disable. So sometimes, I get system hang due to visit register without clock, sometimes not.
The Linux Kernel USB maintainer Alan Stern suggests this kinds of solution. See: http://marc.info/?l=linux-usb&m=138541769810983&w=2.
Cc: stable@vger.kernel.org #v4.9+ Signed-off-by: Peter Chen peter.chen@nxp.com Link: https://lore.kernel.org/r/20190820020503.27080-2-peter.chen@nxp.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/chipidea/udc.c | 32 ++++++++++++++++++++++++-------- 1 file changed, 24 insertions(+), 8 deletions(-)
diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c index 6a5ee8e6da10..67ad40b0a05b 100644 --- a/drivers/usb/chipidea/udc.c +++ b/drivers/usb/chipidea/udc.c @@ -709,12 +709,6 @@ static int _gadget_stop_activity(struct usb_gadget *gadget) struct ci_hdrc *ci = container_of(gadget, struct ci_hdrc, gadget); unsigned long flags;
- spin_lock_irqsave(&ci->lock, flags); - ci->gadget.speed = USB_SPEED_UNKNOWN; - ci->remote_wakeup = 0; - ci->suspended = 0; - spin_unlock_irqrestore(&ci->lock, flags); - /* flush all endpoints */ gadget_for_each_ep(ep, gadget) { usb_ep_fifo_flush(ep); @@ -732,6 +726,12 @@ static int _gadget_stop_activity(struct usb_gadget *gadget) ci->status = NULL; }
+ spin_lock_irqsave(&ci->lock, flags); + ci->gadget.speed = USB_SPEED_UNKNOWN; + ci->remote_wakeup = 0; + ci->suspended = 0; + spin_unlock_irqrestore(&ci->lock, flags); + return 0; }
@@ -1303,6 +1303,10 @@ static int ep_disable(struct usb_ep *ep) return -EBUSY;
spin_lock_irqsave(hwep->lock, flags); + if (hwep->ci->gadget.speed == USB_SPEED_UNKNOWN) { + spin_unlock_irqrestore(hwep->lock, flags); + return 0; + }
/* only internal SW should disable ctrl endpts */
@@ -1392,6 +1396,10 @@ static int ep_queue(struct usb_ep *ep, struct usb_request *req, return -EINVAL;
spin_lock_irqsave(hwep->lock, flags); + if (hwep->ci->gadget.speed == USB_SPEED_UNKNOWN) { + spin_unlock_irqrestore(hwep->lock, flags); + return 0; + } retval = _ep_queue(ep, req, gfp_flags); spin_unlock_irqrestore(hwep->lock, flags); return retval; @@ -1415,8 +1423,8 @@ static int ep_dequeue(struct usb_ep *ep, struct usb_request *req) return -EINVAL;
spin_lock_irqsave(hwep->lock, flags); - - hw_ep_flush(hwep->ci, hwep->num, hwep->dir); + if (hwep->ci->gadget.speed != USB_SPEED_UNKNOWN) + hw_ep_flush(hwep->ci, hwep->num, hwep->dir);
list_for_each_entry_safe(node, tmpnode, &hwreq->tds, td) { dma_pool_free(hwep->td_pool, node->ptr, node->dma); @@ -1487,6 +1495,10 @@ static void ep_fifo_flush(struct usb_ep *ep) }
spin_lock_irqsave(hwep->lock, flags); + if (hwep->ci->gadget.speed == USB_SPEED_UNKNOWN) { + spin_unlock_irqrestore(hwep->lock, flags); + return; + }
hw_ep_flush(hwep->ci, hwep->num, hwep->dir);
@@ -1559,6 +1571,10 @@ static int ci_udc_wakeup(struct usb_gadget *_gadget) int ret = 0;
spin_lock_irqsave(&ci->lock, flags); + if (ci->gadget.speed == USB_SPEED_UNKNOWN) { + spin_unlock_irqrestore(&ci->lock, flags); + return 0; + } if (!ci->remote_wakeup) { ret = -EOPNOTSUPP; goto out;