1// SPDX-License-Identifier: GPL-2.0 2/* 3 * drd.c - DesignWare USB2 DRD Controller Dual-role support 4 * 5 * Copyright (C) 2020 STMicroelectronics 6 * 7 * Author(s): Amelie Delaunay <amelie.delaunay@st.com> 8 */ 9 10#include <linux/clk.h> 11#include <linux/iopoll.h> 12#include <linux/platform_device.h> 13#include <linux/usb/role.h> 14#include "core.h" 15 16static void dwc2_ovr_init(struct dwc2_hsotg *hsotg) 17{ 18 unsigned long flags; 19 u32 gotgctl; 20 21 spin_lock_irqsave(&hsotg->lock, flags); 22 23 gotgctl = dwc2_readl(hsotg, GOTGCTL); 24 gotgctl |= GOTGCTL_BVALOEN | GOTGCTL_AVALOEN | GOTGCTL_VBVALOEN; 25 gotgctl |= GOTGCTL_DBNCE_FLTR_BYPASS; 26 gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL); 27 dwc2_writel(hsotg, gotgctl, GOTGCTL); 28 29 spin_unlock_irqrestore(&hsotg->lock, flags); 30 31 dwc2_force_mode(hsotg, (hsotg->dr_mode == USB_DR_MODE_HOST)); 32} 33 34static int dwc2_ovr_avalid(struct dwc2_hsotg *hsotg, bool valid) 35{ 36 u32 gotgctl = dwc2_readl(hsotg, GOTGCTL); 37 38 /* Check if A-Session is already in the right state */ 39 if ((valid && (gotgctl & GOTGCTL_ASESVLD)) || 40 (!valid && !(gotgctl & GOTGCTL_ASESVLD))) 41 return -EALREADY; 42 43 gotgctl &= ~GOTGCTL_BVALOVAL; 44 if (valid) 45 gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL; 46 else 47 gotgctl &= ~(GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL); 48 dwc2_writel(hsotg, gotgctl, GOTGCTL); 49 50 return 0; 51} 52 53static int dwc2_ovr_bvalid(struct dwc2_hsotg *hsotg, bool valid) 54{ 55 u32 gotgctl = dwc2_readl(hsotg, GOTGCTL); 56 57 /* Check if B-Session is already in the right state */ 58 if ((valid && (gotgctl & GOTGCTL_BSESVLD)) || 59 (!valid && !(gotgctl & GOTGCTL_BSESVLD))) 60 return -EALREADY; 61 62 gotgctl &= ~GOTGCTL_AVALOVAL; 63 if (valid) 64 gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL; 65 else 66 gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL); 67 dwc2_writel(hsotg, gotgctl, GOTGCTL); 68 69 return 0; 70} 71 72static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role) 73{ 74 struct dwc2_hsotg *hsotg = usb_role_switch_get_drvdata(sw); 75 unsigned long flags; 76 int already = 0; 77 78 /* Skip session not in line with dr_mode */ 79 if ((role == USB_ROLE_DEVICE && hsotg->dr_mode == USB_DR_MODE_HOST) || 80 (role == USB_ROLE_HOST && hsotg->dr_mode == USB_DR_MODE_PERIPHERAL)) 81 return -EINVAL; 82 83#if IS_ENABLED(CONFIG_USB_DWC2_PERIPHERAL) || \ 84 IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE) 85 /* Skip session if core is in test mode */ 86 if (role == USB_ROLE_NONE && hsotg->test_mode) { 87 dev_dbg(hsotg->dev, "Core is in test mode\n"); 88 return -EBUSY; 89 } 90#endif 91 92 /* 93 * In case of USB_DR_MODE_PERIPHERAL, clock is disabled at the end of 94 * the probe and enabled on udc_start. 95 * If role-switch set is called before the udc_start, we need to enable 96 * the clock to read/write GOTGCTL and GUSBCFG registers to override 97 * mode and sessions. It is the case if cable is plugged at boot. 98 */ 99 if (!hsotg->ll_hw_enabled && hsotg->clk) { 100 int ret = clk_prepare_enable(hsotg->clk); 101 102 if (ret) 103 return ret; 104 } 105 106 spin_lock_irqsave(&hsotg->lock, flags); 107 108 if (role == USB_ROLE_HOST) { 109 already = dwc2_ovr_avalid(hsotg, true); 110 } else if (role == USB_ROLE_DEVICE) { 111 already = dwc2_ovr_bvalid(hsotg, true); 112 if (dwc2_is_device_enabled(hsotg)) { 113 /* This clear DCTL.SFTDISCON bit */ 114 dwc2_hsotg_core_connect(hsotg); 115 } 116 } else { 117 if (dwc2_is_device_mode(hsotg)) { 118 if (!dwc2_ovr_bvalid(hsotg, false)) 119 /* This set DCTL.SFTDISCON bit */ 120 dwc2_hsotg_core_disconnect(hsotg); 121 } else { 122 dwc2_ovr_avalid(hsotg, false); 123 } 124 } 125 126 spin_unlock_irqrestore(&hsotg->lock, flags); 127 128 if (!already && hsotg->dr_mode == USB_DR_MODE_OTG) 129 /* This will raise a Connector ID Status Change Interrupt */ 130 dwc2_force_mode(hsotg, role == USB_ROLE_HOST); 131 132 if (!hsotg->ll_hw_enabled && hsotg->clk) 133 clk_disable_unprepare(hsotg->clk); 134 135 dev_dbg(hsotg->dev, "%s-session valid\n", 136 role == USB_ROLE_NONE ? "No" : 137 role == USB_ROLE_HOST ? "A" : "B"); 138 139 return 0; 140} 141 142int dwc2_drd_init(struct dwc2_hsotg *hsotg) 143{ 144 struct usb_role_switch_desc role_sw_desc = {0}; 145 struct usb_role_switch *role_sw; 146 int ret; 147 148 if (!device_property_read_bool(hsotg->dev, "usb-role-switch")) 149 return 0; 150 151 role_sw_desc.driver_data = hsotg; 152 role_sw_desc.fwnode = dev_fwnode(hsotg->dev); 153 role_sw_desc.set = dwc2_drd_role_sw_set; 154 role_sw_desc.allow_userspace_control = true; 155 156 role_sw = usb_role_switch_register(hsotg->dev, &role_sw_desc); 157 if (IS_ERR(role_sw)) { 158 ret = PTR_ERR(role_sw); 159 dev_err(hsotg->dev, 160 "failed to register role switch: %d\n", ret); 161 return ret; 162 } 163 164 hsotg->role_sw = role_sw; 165 166 /* Enable override and initialize values */ 167 dwc2_ovr_init(hsotg); 168 169 return 0; 170} 171 172void dwc2_drd_suspend(struct dwc2_hsotg *hsotg) 173{ 174 u32 gintsts, gintmsk; 175 176 if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) { 177 gintmsk = dwc2_readl(hsotg, GINTMSK); 178 gintmsk &= ~GINTSTS_CONIDSTSCHNG; 179 dwc2_writel(hsotg, gintmsk, GINTMSK); 180 gintsts = dwc2_readl(hsotg, GINTSTS); 181 dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS); 182 } 183} 184 185void dwc2_drd_resume(struct dwc2_hsotg *hsotg) 186{ 187 u32 gintsts, gintmsk; 188 189 if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) { 190 gintsts = dwc2_readl(hsotg, GINTSTS); 191 dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS); 192 gintmsk = dwc2_readl(hsotg, GINTMSK); 193 gintmsk |= GINTSTS_CONIDSTSCHNG; 194 dwc2_writel(hsotg, gintmsk, GINTMSK); 195 } 196} 197 198void dwc2_drd_exit(struct dwc2_hsotg *hsotg) 199{ 200 if (hsotg->role_sw) 201 usb_role_switch_unregister(hsotg->role_sw); 202} 203