> From: Marek Szyprowski [mailto:[email protected]]
> Sent: Friday, November 14, 2014 1:19 AM
>
> On 2014-11-13 21:55, Paul Zimmerman wrote:
> >> From: Marek Szyprowski [mailto:[email protected]]
> >> Sent: Thursday, November 13, 2014 7:18 AM
> >>
> >> On 2014-10-31 19:46, Paul Zimmerman wrote:
> >>>> From: Marek Szyprowski [mailto:[email protected]]
> >>>> Sent: Friday, October 31, 2014 3:13 AM
> >>>>
> >>>> This patch adds mutex, which protects initialization and
> >>>> deinitialization procedures against suspend/resume methods.
> >>>>
> >>>> Signed-off-by: Marek Szyprowski <[email protected]>
> >>>> ---
> >>>> drivers/usb/dwc2/core.h | 1 +
> >>>> drivers/usb/dwc2/gadget.c | 20 ++++++++++++++++++++
> >>>> 2 files changed, 21 insertions(+)
> >>>>
> >>>> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
> >>>> index 9f77b4d1c5ff..58732a9a0019 100644
> >>>> --- a/drivers/usb/dwc2/core.h
> >>>> +++ b/drivers/usb/dwc2/core.h
> >>>> @@ -187,6 +187,7 @@ struct s3c_hsotg {
> >>>> struct s3c_hsotg_plat *plat;
> >>>>
> >>>> spinlock_t lock;
> >>>> + struct mutex init_mutex;
> >>>>
> >>>> void __iomem *regs;
> >>>> int irq;
> >>>> diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
> >>>> index d8dda39c9e16..a2e4272a904e 100644
> >>>> --- a/drivers/usb/dwc2/gadget.c
> >>>> +++ b/drivers/usb/dwc2/gadget.c
> >>>> @@ -21,6 +21,7 @@
> >>>> #include <linux/platform_device.h>
> >>>> #include <linux/dma-mapping.h>
> >>>> #include <linux/debugfs.h>
> >>>> +#include <linux/mutex.h>
> >>>> #include <linux/seq_file.h>
> >>>> #include <linux/delay.h>
> >>>> #include <linux/io.h>
> >>>> @@ -2908,6 +2909,7 @@ static int s3c_hsotg_udc_start(struct usb_gadget
> >>>> *gadget,
> >>>> return -EINVAL;
> >>>> }
> >>>>
> >>>> + mutex_lock(&hsotg->init_mutex);
> >>>> WARN_ON(hsotg->driver);
> >>>>
> >>>> driver->driver.bus = NULL;
> >>>> @@ -2933,9 +2935,12 @@ static int s3c_hsotg_udc_start(struct usb_gadget
> >>>> *gadget,
> >>>>
> >>>> dev_info(hsotg->dev, "bound driver %s\n", driver->driver.name);
> >>>>
> >>>> + mutex_unlock(&hsotg->init_mutex);
> >>>> +
> >>>> return 0;
> >>>>
> >>>> err:
> >>>> + mutex_unlock(&hsotg->init_mutex);
> >>>> hsotg->driver = NULL;
> >>>> return ret;
> >>>> }
> >>>> @@ -2957,6 +2962,8 @@ static int s3c_hsotg_udc_stop(struct usb_gadget
> >>>> *gadget,
> >>>> if (!hsotg)
> >>>> return -ENODEV;
> >>>>
> >>>> + mutex_lock(&hsotg->init_mutex);
> >>>> +
> >>>> /* all endpoints should be shutdown */
> >>>> for (ep = 1; ep < hsotg->num_of_eps; ep++)
> >>>> s3c_hsotg_ep_disable(&hsotg->eps[ep].ep);
> >>>> @@ -2974,6 +2981,8 @@ static int s3c_hsotg_udc_stop(struct usb_gadget
> >>>> *gadget,
> >>>>
> >>>> clk_disable(hsotg->clk);
> >>>>
> >>>> + mutex_unlock(&hsotg->init_mutex);
> >>>> +
> >>>> return 0;
> >>>> }
> >>>>
> >>>> @@ -3002,6 +3011,7 @@ static int s3c_hsotg_pullup(struct usb_gadget
> >>>> *gadget, int is_on)
> >>>>
> >>>> dev_dbg(hsotg->dev, "%s: is_on: %d\n", __func__, is_on);
> >>>>
> >>>> + mutex_lock(&hsotg->init_mutex);
> >>>> spin_lock_irqsave(&hsotg->lock, flags);
> >>>> if (is_on) {
> >>>> clk_enable(hsotg->clk);
> >>>> @@ -3013,6 +3023,7 @@ static int s3c_hsotg_pullup(struct usb_gadget
> >>>> *gadget, int is_on)
> >>>>
> >>>> hsotg->gadget.speed = USB_SPEED_UNKNOWN;
> >>>> spin_unlock_irqrestore(&hsotg->lock, flags);
> >>>> + mutex_unlock(&hsotg->init_mutex);
> >>>>
> >>>> return 0;
> >>>> }
> >>>> @@ -3507,6 +3518,7 @@ static int s3c_hsotg_probe(struct platform_device
> >>>> *pdev)
> >>>> }
> >>>>
> >>>> spin_lock_init(&hsotg->lock);
> >>>> + mutex_init(&hsotg->init_mutex);
> >>>>
> >>>> hsotg->irq = ret;
> >>>>
> >>>> @@ -3652,6 +3664,8 @@ static int s3c_hsotg_suspend(struct
> >>>> platform_device *pdev, pm_message_t
> >> state)
> >>>> unsigned long flags;
> >>>> int ret = 0;
> >>>>
> >>>> + mutex_lock(&hsotg->init_mutex);
> >>>> +
> >>>> if (hsotg->driver)
> >>>> dev_info(hsotg->dev, "suspending usb gadget %s\n",
> >>>> hsotg->driver->driver.name);
> >>>> @@ -3674,6 +3688,8 @@ static int s3c_hsotg_suspend(struct
> >>>> platform_device *pdev, pm_message_t
> >> state)
> >>>> clk_disable(hsotg->clk);
> >>>> }
> >>>>
> >>>> + mutex_unlock(&hsotg->init_mutex);
> >>>> +
> >>>> return ret;
> >>>> }
> >>>>
> >>>> @@ -3683,7 +3699,9 @@ static int s3c_hsotg_resume(struct platform_device
> >>>> *pdev)
> >>>> unsigned long flags;
> >>>> int ret = 0;
> >>>>
> >>>> + mutex_lock(&hsotg->init_mutex);
> >>>> if (hsotg->driver) {
> >>>> +
> >>>> dev_info(hsotg->dev, "resuming usb gadget %s\n",
> >>>> hsotg->driver->driver.name);
> >>>>
> >>>> @@ -3699,6 +3717,8 @@ static int s3c_hsotg_resume(struct platform_device
> >>>> *pdev)
> >>>> s3c_hsotg_core_connect(hsotg);
> >>>> spin_unlock_irqrestore(&hsotg->lock, flags);
> >>>>
> >>>> + mutex_unlock(&hsotg->init_mutex);
> >>>> +
> >>>> return ret;
> >>>> }
> >>>>
> >>> Hmm. I can't find any other UDC driver that uses a mutex in its
> >>> suspend/resume functions. Can you explain why this is needed only
> >>> for dwc2?
> >> I've posted this version because I thought you were not convinced that
> >> the patch
> >> "usb: dwc2/gadget: rework suspend/resume code to correctly restore
> >> gadget state"
> >> can add code for initialization and deinitialization in suspend/resume
> >> paths.
> > My problem with that patch was that you were checking the ->enabled
> > flag outside of the spinlock. To address that, you only need to move
> > the check inside of the spinlock. I don't see why a mutex is needed.
>
> It is not that simple. I can add spin_lock() before checking enabled,
> but then
> I would need to spin_unlock() to call regulator_bulk_enable() and
> phy_enable(),
> because both cannot be called from atomic context. This means that the
> spinlock
> in such case will not protect anything and is simply useless.
Ah, OK. So you're using the mutex instead of the ->enabled flag that you
proposed in the "rework suspend/resume code" patch. So this patch is a
replacement for that one. Somehow I was thinking this patch was on top
of that one.
So I guess this is OK, but I would like to get Felipe's opinion about
it before we apply this.
Felipe?
--
Paul
N�����r��y����b�X��ǧv�^�){.n�+����{������^n�r���z���h�����&�� �G���h�(�階�ݢj"���m������z�ޖ���f���h���~�m�
