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