Re: [PATCH v3] usb: dwc3: Runtime get and put usb power_supply handle

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Sun, Aug 04, 2024, Kyle Tso wrote:
> It is possible that the usb power_supply is registered after the probe

Should we defer the dwc3 probe until the power_supply is registered
then?

> of dwc3. In this case, trying to get the usb power_supply during the
> probe will fail and there is no chance to try again. Also the usb
> power_supply might be unregistered at anytime so that the handle of it

This is problematic... If the power_supply is unregistered, the device
is no longer usable.

> in dwc3 would become invalid. To fix this, get the handle right before
> calling to power_supply functions and put it afterward.

Shouldn't the life-cycle of the dwc3 match with the power_supply? How
can we maintain function without the proper power_supply?

BR,
Thinh

> 
> dwc3_gadet_vbus_draw might be in interrupt context. Create a kthread
> worker beforehand and use it to process the "might-sleep"
> power_supply_put ASAP after the property set.
> 
> Fixes: 6f0764b5adea ("usb: dwc3: add a power supply for current control")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Kyle Tso <kyletso@xxxxxxxxxx>
> ---
> v2 -> v3:
> - Only move power_supply_put to a work. Still call _get_by_name and
>   _set_property in dwc3_gadget_vbus_draw.
> - Create a kthread_worker to handle the work
> 
> v1 -> v2:
> - move power_supply_put out of interrupt context
> 
>  drivers/usb/dwc3/core.c   | 29 ++++++++++++----------------
>  drivers/usb/dwc3/core.h   |  6 ++++--
>  drivers/usb/dwc3/gadget.c | 40 +++++++++++++++++++++++++++++++++++----
>  3 files changed, 52 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 734de2a8bd21..82c8376330d7 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1631,8 +1631,6 @@ static void dwc3_get_properties(struct dwc3 *dwc)
>  	u8			tx_thr_num_pkt_prd = 0;
>  	u8			tx_max_burst_prd = 0;
>  	u8			tx_fifo_resize_max_num;
> -	const char		*usb_psy_name;
> -	int			ret;
>  
>  	/* default to highest possible threshold */
>  	lpm_nyet_threshold = 0xf;
> @@ -1667,12 +1665,7 @@ static void dwc3_get_properties(struct dwc3 *dwc)
>  
>  	dwc->sys_wakeup = device_may_wakeup(dwc->sysdev);
>  
> -	ret = device_property_read_string(dev, "usb-psy-name", &usb_psy_name);
> -	if (ret >= 0) {
> -		dwc->usb_psy = power_supply_get_by_name(usb_psy_name);
> -		if (!dwc->usb_psy)
> -			dev_err(dev, "couldn't get usb power supply\n");
> -	}
> +	device_property_read_string(dev, "usb-psy-name", &dwc->usb_psy_name);
>  
>  	dwc->has_lpm_erratum = device_property_read_bool(dev,
>  				"snps,has-lpm-erratum");
> @@ -2132,19 +2125,24 @@ static int dwc3_probe(struct platform_device *pdev)
>  
>  	dwc3_get_software_properties(dwc);
>  
> +	dwc->worker = kthread_create_worker(0, "dwc3-worker");
> +	if (IS_ERR(dwc->worker))
> +		return PTR_ERR(dwc->worker);
> +	sched_set_fifo(dwc->worker->task);
> +
>  	dwc->reset = devm_reset_control_array_get_optional_shared(dev);
>  	if (IS_ERR(dwc->reset)) {
>  		ret = PTR_ERR(dwc->reset);
> -		goto err_put_psy;
> +		goto err_destroy_worker;
>  	}
>  
>  	ret = dwc3_get_clocks(dwc);
>  	if (ret)
> -		goto err_put_psy;
> +		goto err_destroy_worker;
>  
>  	ret = reset_control_deassert(dwc->reset);
>  	if (ret)
> -		goto err_put_psy;
> +		goto err_destroy_worker;
>  
>  	ret = dwc3_clk_enable(dwc);
>  	if (ret)
> @@ -2245,9 +2243,8 @@ static int dwc3_probe(struct platform_device *pdev)
>  	dwc3_clk_disable(dwc);
>  err_assert_reset:
>  	reset_control_assert(dwc->reset);
> -err_put_psy:
> -	if (dwc->usb_psy)
> -		power_supply_put(dwc->usb_psy);
> +err_destroy_worker:
> +	kthread_destroy_worker(dwc->worker);
>  
>  	return ret;
>  }
> @@ -2258,6 +2255,7 @@ static void dwc3_remove(struct platform_device *pdev)
>  
>  	pm_runtime_get_sync(&pdev->dev);
>  
> +	kthread_destroy_worker(dwc->worker);
>  	dwc3_core_exit_mode(dwc);
>  	dwc3_debugfs_exit(dwc);
>  
> @@ -2276,9 +2274,6 @@ static void dwc3_remove(struct platform_device *pdev)
>  	pm_runtime_set_suspended(&pdev->dev);
>  
>  	dwc3_free_event_buffers(dwc);
> -
> -	if (dwc->usb_psy)
> -		power_supply_put(dwc->usb_psy);
>  }
>  
>  #ifdef CONFIG_PM
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 1e561fd8b86e..3fc58204db6e 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -993,6 +993,7 @@ struct dwc3_scratchpad_array {
>  /**
>   * struct dwc3 - representation of our controller
>   * @drd_work: workqueue used for role swapping
> + * @worker: dedicated kthread worker
>   * @ep0_trb: trb which is used for the ctrl_req
>   * @bounce: address of bounce buffer
>   * @setup_buf: used while precessing STD USB requests
> @@ -1045,7 +1046,7 @@ struct dwc3_scratchpad_array {
>   * @role_sw: usb_role_switch handle
>   * @role_switch_default_mode: default operation mode of controller while
>   *			usb role is USB_ROLE_NONE.
> - * @usb_psy: pointer to power supply interface.
> + * @usb_psy_name: name of the usb power supply interface
>   * @usb2_phy: pointer to USB2 PHY
>   * @usb3_phy: pointer to USB3 PHY
>   * @usb2_generic_phy: pointer to array of USB2 PHYs
> @@ -1163,6 +1164,7 @@ struct dwc3_scratchpad_array {
>   */
>  struct dwc3 {
>  	struct work_struct	drd_work;
> +	struct kthread_worker	*worker;
>  	struct dwc3_trb		*ep0_trb;
>  	void			*bounce;
>  	u8			*setup_buf;
> @@ -1223,7 +1225,7 @@ struct dwc3 {
>  	struct usb_role_switch	*role_sw;
>  	enum usb_dr_mode	role_switch_default_mode;
>  
> -	struct power_supply	*usb_psy;
> +	const char		*usb_psy_name;
>  
>  	u32			fladj;
>  	u32			ref_clk_per;
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 89fc690fdf34..1ff583281eff 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -30,6 +30,11 @@
>  #define DWC3_ALIGN_FRAME(d, n)	(((d)->frame_number + ((d)->interval * (n))) \
>  					& ~((d)->interval - 1))
>  
> +struct dwc3_psy_put {
> +	struct kthread_work work;
> +	struct power_supply *psy;
> +};
> +
>  /**
>   * dwc3_gadget_set_test_mode - enables usb2 test modes
>   * @dwc: pointer to our context structure
> @@ -3047,22 +3052,49 @@ static void dwc3_gadget_set_ssp_rate(struct usb_gadget *g,
>  	spin_unlock_irqrestore(&dwc->lock, flags);
>  }
>  
> +static void dwc3_gadget_psy_put(struct kthread_work *work)
> +{
> +	struct dwc3_psy_put	*psy_put = container_of(work, struct dwc3_psy_put, work);
> +
> +	power_supply_put(psy_put->psy);
> +	kfree(psy_put);
> +}
> +
>  static int dwc3_gadget_vbus_draw(struct usb_gadget *g, unsigned int mA)
>  {
> -	struct dwc3		*dwc = gadget_to_dwc(g);
> +	struct dwc3			*dwc = gadget_to_dwc(g);
> +	struct power_supply		*usb_psy;
>  	union power_supply_propval	val = {0};
> +	struct dwc3_psy_put		*psy_put;
>  	int				ret;
>  
>  	if (dwc->usb2_phy)
>  		return usb_phy_set_power(dwc->usb2_phy, mA);
>  
> -	if (!dwc->usb_psy)
> +	if (!dwc->usb_psy_name)
>  		return -EOPNOTSUPP;
>  
> +	usb_psy = power_supply_get_by_name(dwc->usb_psy_name);
> +	if (!usb_psy) {
> +		dev_err(dwc->dev, "couldn't get usb power supply\n");
> +		return -ENODEV;
> +	}
> +
>  	val.intval = 1000 * mA;
> -	ret = power_supply_set_property(dwc->usb_psy, POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT, &val);
> +	ret = power_supply_set_property(usb_psy, POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT, &val);
> +	if (ret < 0) {
> +		dev_err(dwc->dev, "failed to set power supply property\n");
> +		return ret;
> +	}
>  
> -	return ret;
> +	psy_put = kzalloc(sizeof(*psy_put), GFP_ATOMIC);
> +	if (!psy_put)
> +		return -ENOMEM;
> +	kthread_init_work(&psy_put->work, dwc3_gadget_psy_put);
> +	psy_put->psy = usb_psy;
> +	kthread_queue_work(dwc->worker, &psy_put->work);
> +
> +	return 0;
>  }
>  
>  /**
> -- 
> 2.46.0.rc2.264.g509ed76dc8-goog
> 




[Index of Archives]     [Linux Media]     [Linux Input]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Old Linux USB Devel Archive]

  Powered by Linux