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| 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 <[email protected]> |
| 8 | + */ |
| 9 | + |
| 10 | +#include <linux/iopoll.h> |
| 11 | +#include <linux/platform_device.h> |
| 12 | +#include <linux/usb/role.h> |
| 13 | +#include "core.h" |
| 14 | + |
| 15 | +static void dwc2_ovr_init(struct dwc2_hsotg *hsotg) |
| 16 | +{ |
| 17 | + unsigned long flags; |
| 18 | + u32 gotgctl; |
| 19 | + |
| 20 | + spin_lock_irqsave(&hsotg->lock, flags); |
| 21 | + |
| 22 | + gotgctl = dwc2_readl(hsotg, GOTGCTL); |
| 23 | + gotgctl |= GOTGCTL_BVALOEN | GOTGCTL_AVALOEN | GOTGCTL_VBVALOEN; |
| 24 | + gotgctl |= GOTGCTL_DBNCE_FLTR_BYPASS; |
| 25 | + gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL); |
| 26 | + dwc2_writel(hsotg, gotgctl, GOTGCTL); |
| 27 | + |
| 28 | + dwc2_force_mode(hsotg, false); |
| 29 | + |
| 30 | + spin_unlock_irqrestore(&hsotg->lock, flags); |
| 31 | +} |
| 32 | + |
| 33 | +static int dwc2_ovr_avalid(struct dwc2_hsotg *hsotg, bool valid) |
| 34 | +{ |
| 35 | + u32 gotgctl = dwc2_readl(hsotg, GOTGCTL); |
| 36 | + |
| 37 | + /* Check if A-Session is already in the right state */ |
| 38 | + if ((valid && (gotgctl & GOTGCTL_ASESVLD)) || |
| 39 | + (!valid && !(gotgctl & GOTGCTL_ASESVLD))) |
| 40 | + return -EALREADY; |
| 41 | + |
| 42 | + if (valid) |
| 43 | + gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL; |
| 44 | + else |
| 45 | + gotgctl &= ~(GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL); |
| 46 | + dwc2_writel(hsotg, gotgctl, GOTGCTL); |
| 47 | + |
| 48 | + return 0; |
| 49 | +} |
| 50 | + |
| 51 | +static int dwc2_ovr_bvalid(struct dwc2_hsotg *hsotg, bool valid) |
| 52 | +{ |
| 53 | + u32 gotgctl = dwc2_readl(hsotg, GOTGCTL); |
| 54 | + |
| 55 | + /* Check if B-Session is already in the right state */ |
| 56 | + if ((valid && (gotgctl & GOTGCTL_BSESVLD)) || |
| 57 | + (!valid && !(gotgctl & GOTGCTL_BSESVLD))) |
| 58 | + return -EALREADY; |
| 59 | + |
| 60 | + if (valid) |
| 61 | + gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL; |
| 62 | + else |
| 63 | + gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL); |
| 64 | + dwc2_writel(hsotg, gotgctl, GOTGCTL); |
| 65 | + |
| 66 | + return 0; |
| 67 | +} |
| 68 | + |
| 69 | +static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role) |
| 70 | +{ |
| 71 | + struct dwc2_hsotg *hsotg = usb_role_switch_get_drvdata(sw); |
| 72 | + unsigned long flags; |
| 73 | + int already = 0; |
| 74 | + |
| 75 | + /* Skip session not in line with dr_mode */ |
| 76 | + if ((role == USB_ROLE_DEVICE && hsotg->dr_mode == USB_DR_MODE_HOST) || |
| 77 | + (role == USB_ROLE_HOST && hsotg->dr_mode == USB_DR_MODE_PERIPHERAL)) |
| 78 | + return -EINVAL; |
| 79 | + |
| 80 | +#if IS_ENABLED(CONFIG_USB_DWC2_PERIPHERAL) || \ |
| 81 | + IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE) |
| 82 | + /* Skip session if core is in test mode */ |
| 83 | + if (role == USB_ROLE_NONE && hsotg->test_mode) { |
| 84 | + dev_dbg(hsotg->dev, "Core is in test mode\n"); |
| 85 | + return -EBUSY; |
| 86 | + } |
| 87 | +#endif |
| 88 | + |
| 89 | + spin_lock_irqsave(&hsotg->lock, flags); |
| 90 | + |
| 91 | + if (role == USB_ROLE_HOST) { |
| 92 | + already = dwc2_ovr_avalid(hsotg, true); |
| 93 | + } else if (role == USB_ROLE_DEVICE) { |
| 94 | + already = dwc2_ovr_bvalid(hsotg, true); |
| 95 | + /* This clear DCTL.SFTDISCON bit */ |
| 96 | + dwc2_hsotg_core_connect(hsotg); |
| 97 | + } else { |
| 98 | + if (dwc2_is_device_mode(hsotg)) { |
| 99 | + if (!dwc2_ovr_bvalid(hsotg, false)) |
| 100 | + /* This set DCTL.SFTDISCON bit */ |
| 101 | + dwc2_hsotg_core_disconnect(hsotg); |
| 102 | + } else { |
| 103 | + dwc2_ovr_avalid(hsotg, false); |
| 104 | + } |
| 105 | + } |
| 106 | + |
| 107 | + spin_unlock_irqrestore(&hsotg->lock, flags); |
| 108 | + |
| 109 | + if (!already && hsotg->dr_mode == USB_DR_MODE_OTG) |
| 110 | + /* This will raise a Connector ID Status Change Interrupt */ |
| 111 | + dwc2_force_mode(hsotg, role == USB_ROLE_HOST); |
| 112 | + |
| 113 | + dev_dbg(hsotg->dev, "%s-session valid\n", |
| 114 | + role == USB_ROLE_NONE ? "No" : |
| 115 | + role == USB_ROLE_HOST ? "A" : "B"); |
| 116 | + |
| 117 | + return 0; |
| 118 | +} |
| 119 | + |
| 120 | +int dwc2_drd_init(struct dwc2_hsotg *hsotg) |
| 121 | +{ |
| 122 | + struct usb_role_switch_desc role_sw_desc = {0}; |
| 123 | + struct usb_role_switch *role_sw; |
| 124 | + int ret; |
| 125 | + |
| 126 | + if (!device_property_read_bool(hsotg->dev, "usb-role-switch")) |
| 127 | + return 0; |
| 128 | + |
| 129 | + role_sw_desc.driver_data = hsotg; |
| 130 | + role_sw_desc.fwnode = dev_fwnode(hsotg->dev); |
| 131 | + role_sw_desc.set = dwc2_drd_role_sw_set; |
| 132 | + role_sw_desc.allow_userspace_control = true; |
| 133 | + |
| 134 | + role_sw = usb_role_switch_register(hsotg->dev, &role_sw_desc); |
| 135 | + if (IS_ERR(role_sw)) { |
| 136 | + ret = PTR_ERR(role_sw); |
| 137 | + dev_err(hsotg->dev, |
| 138 | + "failed to register role switch: %d\n", ret); |
| 139 | + return ret; |
| 140 | + } |
| 141 | + |
| 142 | + hsotg->role_sw = role_sw; |
| 143 | + |
| 144 | + /* Enable override and initialize values */ |
| 145 | + dwc2_ovr_init(hsotg); |
| 146 | + |
| 147 | + return 0; |
| 148 | +} |
| 149 | + |
| 150 | +void dwc2_drd_suspend(struct dwc2_hsotg *hsotg) |
| 151 | +{ |
| 152 | + u32 gintsts, gintmsk; |
| 153 | + |
| 154 | + if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) { |
| 155 | + gintmsk = dwc2_readl(hsotg, GINTMSK); |
| 156 | + gintmsk &= ~GINTSTS_CONIDSTSCHNG; |
| 157 | + dwc2_writel(hsotg, gintmsk, GINTMSK); |
| 158 | + gintsts = dwc2_readl(hsotg, GINTSTS); |
| 159 | + dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS); |
| 160 | + } |
| 161 | +} |
| 162 | + |
| 163 | +void dwc2_drd_resume(struct dwc2_hsotg *hsotg) |
| 164 | +{ |
| 165 | + u32 gintsts, gintmsk; |
| 166 | + |
| 167 | + if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) { |
| 168 | + gintsts = dwc2_readl(hsotg, GINTSTS); |
| 169 | + dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS); |
| 170 | + gintmsk = dwc2_readl(hsotg, GINTMSK); |
| 171 | + gintmsk |= GINTSTS_CONIDSTSCHNG; |
| 172 | + dwc2_writel(hsotg, gintmsk, GINTMSK); |
| 173 | + } |
| 174 | +} |
| 175 | + |
| 176 | +void dwc2_drd_exit(struct dwc2_hsotg *hsotg) |
| 177 | +{ |
| 178 | + if (hsotg->role_sw) |
| 179 | + usb_role_switch_unregister(hsotg->role_sw); |
| 180 | +} |
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