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

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@vger.kernel.org Signed-off-by: Kyle Tso kyletso@google.com

---

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