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 >