drivers/usb/dwc2/drd.c

Source file repositories/reference/linux-study-clean/drivers/usb/dwc2/drd.c

File Facts

System
Linux kernel
Corpus path
drivers/usb/dwc2/drd.c
Extension
.c
Size
7354 bytes
Lines
260
Domain
Driver Families
Bucket
drivers/usb
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (dwc2_is_device_enabled(hsotg)) {
			/* This clear DCTL.SFTDISCON bit */
			dwc2_hsotg_core_connect(hsotg);
		}
	} else {
		if (dwc2_is_device_mode(hsotg)) {
			if (!dwc2_ovr_bvalid(hsotg, false))
				/* This set DCTL.SFTDISCON bit */
				dwc2_hsotg_core_disconnect(hsotg);
		} else {
			dwc2_ovr_avalid(hsotg, false);
		}
	}

	spin_unlock_irqrestore(&hsotg->lock, flags);

	if (!already && hsotg->dr_mode == USB_DR_MODE_OTG)
		/* This will raise a Connector ID Status Change Interrupt */
		dwc2_force_mode(hsotg, role == USB_ROLE_HOST);

	if (!hsotg->ll_hw_enabled && hsotg->clk)
		clk_disable_unprepare(hsotg->clk);

	dev_dbg(hsotg->dev, "%s-session valid\n",
		role == USB_ROLE_NONE ? "No" :
		role == USB_ROLE_HOST ? "A" : "B");

	return 0;
}

int dwc2_drd_init(struct dwc2_hsotg *hsotg)
{
	struct usb_role_switch_desc role_sw_desc = {0};
	struct usb_role_switch *role_sw;
	int ret;

	if (!device_property_read_bool(hsotg->dev, "usb-role-switch"))
		return 0;

	hsotg->role_sw_default_mode = usb_get_role_switch_default_mode(hsotg->dev);
	role_sw_desc.driver_data = hsotg;
	role_sw_desc.fwnode = dev_fwnode(hsotg->dev);
	role_sw_desc.set = dwc2_drd_role_sw_set;
	role_sw_desc.allow_userspace_control = true;

	role_sw = usb_role_switch_register(hsotg->dev, &role_sw_desc);
	if (IS_ERR(role_sw)) {
		ret = PTR_ERR(role_sw);
		dev_err(hsotg->dev,
			"failed to register role switch: %d\n", ret);
		return ret;
	}

	hsotg->role_sw = role_sw;

	/* Enable override and initialize values */
	dwc2_ovr_init(hsotg);

	return 0;
}

void dwc2_drd_suspend(struct dwc2_hsotg *hsotg)
{
	u32 gintsts, gintmsk;

	if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) {
		gintmsk = dwc2_readl(hsotg, GINTMSK);
		gintmsk &= ~GINTSTS_CONIDSTSCHNG;
		dwc2_writel(hsotg, gintmsk, GINTMSK);
		gintsts = dwc2_readl(hsotg, GINTSTS);
		dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS);
	}
}

void dwc2_drd_resume(struct dwc2_hsotg *hsotg)
{
	u32 gintsts, gintmsk;
	enum usb_role role;

	if (hsotg->role_sw) {
		/* get last known role (as the get ops isn't implemented by this driver) */
		role = usb_role_switch_get_role(hsotg->role_sw);

		if (role == USB_ROLE_NONE) {
			if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
				role = USB_ROLE_HOST;
			else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
				role = USB_ROLE_DEVICE;
		}

Annotation

Implementation Notes