Hello, On 2014-10-25 03:16, Paul Zimmerman wrote:
From: Marek Szyprowski [mailto:m.szyprow...@samsung.com] Sent: Monday, October 20, 2014 3:46 AMSuspend/resume code assumed that the gadget was always enabled and connected to usb bus. This means that the actual state of the gadget (soft-enabled/disabled or connected/disconnected) was not correctly preserved on suspend/resume cycle. This patch fixes this issue. Signed-off-by: Marek Szyprowski <m.szyprow...@samsung.com> --- drivers/usb/dwc2/core.h | 4 +++- drivers/usb/dwc2/gadget.c | 43 +++++++++++++++++++++++++++---------------- 2 files changed, 30 insertions(+), 17 deletions(-) diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h index bf015ab3b44c..3648b76a18b4 100644 --- a/drivers/usb/dwc2/core.h +++ b/drivers/usb/dwc2/core.h @@ -210,7 +210,9 @@ struct s3c_hsotg { u8 ctrl_buff[8]; struct usb_gadget gadget; - unsigned int setup; + unsigned int setup:1; + unsigned int connected:1; + unsigned int enabled:1; unsigned long last_rst; struct s3c_hsotg_ep *eps; }; diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c index 0d34cfc71bfb..c6c6cf982c90 100644 --- a/drivers/usb/dwc2/gadget.c +++ b/drivers/usb/dwc2/gadget.c @@ -2925,6 +2925,8 @@ static int s3c_hsotg_udc_start(struct usb_gadget *gadget, spin_lock_irqsave(&hsotg->lock, flags); s3c_hsotg_init(hsotg); s3c_hsotg_core_init_disconnected(hsotg); + hsotg->enabled = 1; + hsotg->connected = 0; spin_unlock_irqrestore(&hsotg->lock, flags); dev_info(hsotg->dev, "bound driver %s\n", driver->driver.name); @@ -2961,6 +2963,8 @@ static int s3c_hsotg_udc_stop(struct usb_gadget *gadget, hsotg->driver = NULL; hsotg->gadget.speed = USB_SPEED_UNKNOWN; + hsotg->enabled = 0; + hsotg->connected = 0; spin_unlock_irqrestore(&hsotg->lock, flags); @@ -2999,11 +3003,14 @@ static int s3c_hsotg_pullup(struct usb_gadget *gadget, int is_on) dev_dbg(hsotg->dev, "%s: is_on: %d\n", __func__, is_on); spin_lock_irqsave(&hsotg->lock, flags); + if (is_on) { clk_enable(hsotg->clk); + hsotg->connected = 1; s3c_hsotg_core_connect(hsotg); } else { s3c_hsotg_core_disconnect(hsotg); + hsotg->connected = 0; clk_disable(hsotg->clk); } @@ -3652,16 +3659,18 @@ static int s3c_hsotg_suspend(struct platform_device *pdev, pm_message_t state) dev_info(hsotg->dev, "suspending usb gadget %s\n", hsotg->driver->driver.name); - spin_lock_irqsave(&hsotg->lock, flags); - s3c_hsotg_core_disconnect(hsotg); - s3c_hsotg_disconnect(hsotg); - hsotg->gadget.speed = USB_SPEED_UNKNOWN; - spin_unlock_irqrestore(&hsotg->lock, flags); + if (hsotg->enabled) {Hmm. Are you sure it's safe to check ->enabled outside of the spinlock? What happens if s3c_hsotg_udc_stop() runs right after this, before the spinlock is taken, and disables stuff? Sure, it's a tiny window, but still...
This code is called only in system suspend path, when userspace has been already frozen. udc_stop() can be called only as a result of userspace action, so it is imho safe to
assume that the above code doesn't need additional locking. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
