drivers/usb/dwc2/drd.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * drd.c - DesignWare USB2 DRD Controller Dual-role support
  *
  * Copyright (C) 2020 STMicroelectronics
  *
  * Author(s): Amelie Delaunay <amelie.delaunay@st.com>
  */

 #include <linux/clk.h>
 #include <linux/iopoll.h>
 #include <linux/platform_device.h>
 #include <linux/usb/role.h>
 #include "core.h"

 #define dwc2_ovr_gotgctl(gotgctl) \
 	((gotgctl) |= GOTGCTL_BVALOEN | GOTGCTL_AVALOEN | GOTGCTL_VBVALOEN | \
 	 GOTGCTL_DBNCE_FLTR_BYPASS)

 static void dwc2_ovr_init(struct dwc2_hsotg *hsotg)
 {
 	unsigned long flags;
 	u32 gotgctl;

 	spin_lock_irqsave(&hsotg->lock, flags);

 	gotgctl = dwc2_readl(hsotg, GOTGCTL);
 	dwc2_ovr_gotgctl(gotgctl);
 	gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
 	if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
 		gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL;
 	else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
 		gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL;
 	dwc2_writel(hsotg, gotgctl, GOTGCTL);

 	spin_unlock_irqrestore(&hsotg->lock, flags);

 	dwc2_force_mode(hsotg, (hsotg->dr_mode == USB_DR_MODE_HOST));
 }

 static int dwc2_ovr_avalid(struct dwc2_hsotg *hsotg, bool valid)
 {
 	u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);

 	/* Check if A-Session is already in the right state */
 	if ((valid && (gotgctl & GOTGCTL_ASESVLD)) ||
 	    (!valid && !(gotgctl & GOTGCTL_ASESVLD)))
 		return -EALREADY;

 	/* Always enable overrides to handle the resume case */
 	dwc2_ovr_gotgctl(gotgctl);

 	gotgctl &= ~GOTGCTL_BVALOVAL;
 	if (valid)
 		gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL;
 	else
 		gotgctl &= ~(GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
 	dwc2_writel(hsotg, gotgctl, GOTGCTL);

 	return 0;
 }

 static int dwc2_ovr_bvalid(struct dwc2_hsotg *hsotg, bool valid)
 {
 	u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);

 	/* Check if B-Session is already in the right state */
 	if ((valid && (gotgctl & GOTGCTL_BSESVLD)) ||
 	    (!valid && !(gotgctl & GOTGCTL_BSESVLD)))
 		return -EALREADY;

 	/* Always enable overrides to handle the resume case */
 	dwc2_ovr_gotgctl(gotgctl);

 	gotgctl &= ~GOTGCTL_AVALOVAL;
 	if (valid)
 		gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL;
 	else
 		gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL);
 	dwc2_writel(hsotg, gotgctl, GOTGCTL);

 	return 0;
 }

 static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
 {
 	struct dwc2_hsotg *hsotg = usb_role_switch_get_drvdata(sw);
 	unsigned long flags;
 	int already = 0;

 	/* Skip session not in line with dr_mode */
 	if ((role == USB_ROLE_DEVICE && hsotg->dr_mode == USB_DR_MODE_HOST) ||
 	    (role == USB_ROLE_HOST && hsotg->dr_mode == USB_DR_MODE_PERIPHERAL))
 		return -EINVAL;

 #if IS_ENABLED(CONFIG_USB_DWC2_PERIPHERAL) || \
 	IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE)
 	/* Skip session if core is in test mode */
 	if (role == USB_ROLE_NONE && hsotg->test_mode) {
 		dev_dbg(hsotg->dev, "Core is in test mode\n");
 		return -EBUSY;
 	}
 #endif

 	/*
 	 * In case of USB_DR_MODE_PERIPHERAL, clock is disabled at the end of
 	 * the probe and enabled on udc_start.
 	 * If role-switch set is called before the udc_start, we need to enable
 	 * the clock to read/write GOTGCTL and GUSBCFG registers to override
 	 * mode and sessions. It is the case if cable is plugged at boot.
 	 */
 	if (!hsotg->ll_hw_enabled && hsotg->clk) {
 		int ret = clk_prepare_enable(hsotg->clk);

 		if (ret)
 			return ret;
 	}

 	spin_lock_irqsave(&hsotg->lock, flags);

 	if (role == USB_ROLE_NONE) {
 		/* default operation mode when usb role is 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;
 	}

 	if (role == USB_ROLE_HOST) {
 		already = dwc2_ovr_avalid(hsotg, true);
 	} else if (role == USB_ROLE_DEVICE) {
 		already = dwc2_ovr_bvalid(hsotg, true);
 		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;
 		}

 		/* restore last role that may have been lost */
 		if (role == USB_ROLE_HOST)
 			dwc2_ovr_avalid(hsotg, true);
 		else if (role == USB_ROLE_DEVICE)
 			dwc2_ovr_bvalid(hsotg, true);

 		dwc2_force_mode(hsotg, role == USB_ROLE_HOST);

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

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

 void dwc2_drd_exit(struct dwc2_hsotg *hsotg)
 {
 	if (hsotg->role_sw)
 		usb_role_switch_unregister(hsotg->role_sw);
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* drd.c - DesignWare USB2 DRD Controller Dual-role support
	*
	* Copyright (C) 2020 STMicroelectronics
	*
	* Author(s): Amelie Delaunay <amelie.delaunay@st.com>
	*/

	#include <linux/clk.h>
	#include <linux/iopoll.h>
	#include <linux/platform_device.h>
	#include <linux/usb/role.h>
	#include "core.h"

	#define dwc2_ovr_gotgctl(gotgctl) \
	((gotgctl) \|= GOTGCTL_BVALOEN \| GOTGCTL_AVALOEN \| GOTGCTL_VBVALOEN \| \
	GOTGCTL_DBNCE_FLTR_BYPASS)

	static void dwc2_ovr_init(struct dwc2_hsotg *hsotg)
	{
	unsigned long flags;
	u32 gotgctl;

	spin_lock_irqsave(&hsotg->lock, flags);

	gotgctl = dwc2_readl(hsotg, GOTGCTL);
	dwc2_ovr_gotgctl(gotgctl);
	gotgctl &= ~(GOTGCTL_BVALOVAL \| GOTGCTL_AVALOVAL \| GOTGCTL_VBVALOVAL);
	if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
	gotgctl \|= GOTGCTL_AVALOVAL \| GOTGCTL_VBVALOVAL;
	else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
	gotgctl \|= GOTGCTL_BVALOVAL \| GOTGCTL_VBVALOVAL;
	dwc2_writel(hsotg, gotgctl, GOTGCTL);

	spin_unlock_irqrestore(&hsotg->lock, flags);

	dwc2_force_mode(hsotg, (hsotg->dr_mode == USB_DR_MODE_HOST));
	}

	static int dwc2_ovr_avalid(struct dwc2_hsotg *hsotg, bool valid)
	{
	u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);

	/* Check if A-Session is already in the right state */
	if ((valid && (gotgctl & GOTGCTL_ASESVLD)) \|\|
	(!valid && !(gotgctl & GOTGCTL_ASESVLD)))
	return -EALREADY;

	/* Always enable overrides to handle the resume case */
	dwc2_ovr_gotgctl(gotgctl);

	gotgctl &= ~GOTGCTL_BVALOVAL;
	if (valid)
	gotgctl \|= GOTGCTL_AVALOVAL \| GOTGCTL_VBVALOVAL;
	else
	gotgctl &= ~(GOTGCTL_AVALOVAL \| GOTGCTL_VBVALOVAL);
	dwc2_writel(hsotg, gotgctl, GOTGCTL);

	return 0;
	}

	static int dwc2_ovr_bvalid(struct dwc2_hsotg *hsotg, bool valid)
	{
	u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);

	/* Check if B-Session is already in the right state */
	if ((valid && (gotgctl & GOTGCTL_BSESVLD)) \|\|
	(!valid && !(gotgctl & GOTGCTL_BSESVLD)))
	return -EALREADY;

	/* Always enable overrides to handle the resume case */
	dwc2_ovr_gotgctl(gotgctl);

	gotgctl &= ~GOTGCTL_AVALOVAL;
	if (valid)
	gotgctl \|= GOTGCTL_BVALOVAL \| GOTGCTL_VBVALOVAL;
	else
	gotgctl &= ~(GOTGCTL_BVALOVAL \| GOTGCTL_VBVALOVAL);
	dwc2_writel(hsotg, gotgctl, GOTGCTL);

	return 0;
	}

	static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
	{
	struct dwc2_hsotg *hsotg = usb_role_switch_get_drvdata(sw);
	unsigned long flags;
	int already = 0;

	/* Skip session not in line with dr_mode */
	if ((role == USB_ROLE_DEVICE && hsotg->dr_mode == USB_DR_MODE_HOST) \|\|
	(role == USB_ROLE_HOST && hsotg->dr_mode == USB_DR_MODE_PERIPHERAL))
	return -EINVAL;

	#if IS_ENABLED(CONFIG_USB_DWC2_PERIPHERAL) \|\| \
	IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE)
	/* Skip session if core is in test mode */
	if (role == USB_ROLE_NONE && hsotg->test_mode) {
	dev_dbg(hsotg->dev, "Core is in test mode\n");
	return -EBUSY;
	}
	#endif

	/*
	* In case of USB_DR_MODE_PERIPHERAL, clock is disabled at the end of
	* the probe and enabled on udc_start.
	* If role-switch set is called before the udc_start, we need to enable
	* the clock to read/write GOTGCTL and GUSBCFG registers to override
	* mode and sessions. It is the case if cable is plugged at boot.
	*/
	if (!hsotg->ll_hw_enabled && hsotg->clk) {
	int ret = clk_prepare_enable(hsotg->clk);

	if (ret)
	return ret;
	}

	spin_lock_irqsave(&hsotg->lock, flags);

	if (role == USB_ROLE_NONE) {
	/* default operation mode when usb role is 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;
	}

	if (role == USB_ROLE_HOST) {
	already = dwc2_ovr_avalid(hsotg, true);
	} else if (role == USB_ROLE_DEVICE) {
	already = dwc2_ovr_bvalid(hsotg, true);
	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;
	}

	/* restore last role that may have been lost */
	if (role == USB_ROLE_HOST)
	dwc2_ovr_avalid(hsotg, true);
	else if (role == USB_ROLE_DEVICE)
	dwc2_ovr_bvalid(hsotg, true);

	dwc2_force_mode(hsotg, role == USB_ROLE_HOST);

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

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

	void dwc2_drd_exit(struct dwc2_hsotg *hsotg)
	{
	if (hsotg->role_sw)
	usb_role_switch_unregister(hsotg->role_sw);
	}