1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * f_serial.c - generic USB serial function driver 4 * 5 * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com) 6 * Copyright (C) 2008 by David Brownell 7 * Copyright (C) 2008 by Nokia Corporation 8 * 9 * This software is distributed under the terms of the GNU General 10 * Public License ("GPL") as published by the Free Software Foundation, 11 * either version 2 of that License or (at your option) any later version. 12 */ 13 14 #include <linux/slab.h> 15 #include <linux/kernel.h> 16 #include <linux/module.h> 17 #include <linux/device.h> 18 19 #include "u_serial.h" 20 21 22 /* 23 * This function packages a simple "generic serial" port with no real 24 * control mechanisms, just raw data transfer over two bulk endpoints. 25 * 26 * Because it's not standardized, this isn't as interoperable as the 27 * CDC ACM driver. However, for many purposes it's just as functional 28 * if you can arrange appropriate host side drivers. 29 */ 30 31 struct f_gser { 32 struct gserial port; 33 u8 data_id; 34 u8 port_num; 35 }; 36 37 static inline struct f_gser *func_to_gser(struct usb_function *f) 38 { 39 return container_of(f, struct f_gser, port.func); 40 } 41 42 /*-------------------------------------------------------------------------*/ 43 44 /* interface descriptor: */ 45 46 static struct usb_interface_descriptor gser_interface_desc = { 47 .bLength = USB_DT_INTERFACE_SIZE, 48 .bDescriptorType = USB_DT_INTERFACE, 49 /* .bInterfaceNumber = DYNAMIC */ 50 .bNumEndpoints = 2, 51 .bInterfaceClass = USB_CLASS_VENDOR_SPEC, 52 .bInterfaceSubClass = 0, 53 .bInterfaceProtocol = 0, 54 /* .iInterface = DYNAMIC */ 55 }; 56 57 /* full speed support: */ 58 59 static struct usb_endpoint_descriptor gser_fs_in_desc = { 60 .bLength = USB_DT_ENDPOINT_SIZE, 61 .bDescriptorType = USB_DT_ENDPOINT, 62 .bEndpointAddress = USB_DIR_IN, 63 .bmAttributes = USB_ENDPOINT_XFER_BULK, 64 }; 65 66 static struct usb_endpoint_descriptor gser_fs_out_desc = { 67 .bLength = USB_DT_ENDPOINT_SIZE, 68 .bDescriptorType = USB_DT_ENDPOINT, 69 .bEndpointAddress = USB_DIR_OUT, 70 .bmAttributes = USB_ENDPOINT_XFER_BULK, 71 }; 72 73 static struct usb_descriptor_header *gser_fs_function[] = { 74 (struct usb_descriptor_header *) &gser_interface_desc, 75 (struct usb_descriptor_header *) &gser_fs_in_desc, 76 (struct usb_descriptor_header *) &gser_fs_out_desc, 77 NULL, 78 }; 79 80 /* high speed support: */ 81 82 static struct usb_endpoint_descriptor gser_hs_in_desc = { 83 .bLength = USB_DT_ENDPOINT_SIZE, 84 .bDescriptorType = USB_DT_ENDPOINT, 85 .bmAttributes = USB_ENDPOINT_XFER_BULK, 86 .wMaxPacketSize = cpu_to_le16(512), 87 }; 88 89 static struct usb_endpoint_descriptor gser_hs_out_desc = { 90 .bLength = USB_DT_ENDPOINT_SIZE, 91 .bDescriptorType = USB_DT_ENDPOINT, 92 .bmAttributes = USB_ENDPOINT_XFER_BULK, 93 .wMaxPacketSize = cpu_to_le16(512), 94 }; 95 96 static struct usb_descriptor_header *gser_hs_function[] = { 97 (struct usb_descriptor_header *) &gser_interface_desc, 98 (struct usb_descriptor_header *) &gser_hs_in_desc, 99 (struct usb_descriptor_header *) &gser_hs_out_desc, 100 NULL, 101 }; 102 103 static struct usb_endpoint_descriptor gser_ss_in_desc = { 104 .bLength = USB_DT_ENDPOINT_SIZE, 105 .bDescriptorType = USB_DT_ENDPOINT, 106 .bmAttributes = USB_ENDPOINT_XFER_BULK, 107 .wMaxPacketSize = cpu_to_le16(1024), 108 }; 109 110 static struct usb_endpoint_descriptor gser_ss_out_desc = { 111 .bLength = USB_DT_ENDPOINT_SIZE, 112 .bDescriptorType = USB_DT_ENDPOINT, 113 .bmAttributes = USB_ENDPOINT_XFER_BULK, 114 .wMaxPacketSize = cpu_to_le16(1024), 115 }; 116 117 static struct usb_ss_ep_comp_descriptor gser_ss_bulk_comp_desc = { 118 .bLength = sizeof gser_ss_bulk_comp_desc, 119 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP, 120 }; 121 122 static struct usb_descriptor_header *gser_ss_function[] = { 123 (struct usb_descriptor_header *) &gser_interface_desc, 124 (struct usb_descriptor_header *) &gser_ss_in_desc, 125 (struct usb_descriptor_header *) &gser_ss_bulk_comp_desc, 126 (struct usb_descriptor_header *) &gser_ss_out_desc, 127 (struct usb_descriptor_header *) &gser_ss_bulk_comp_desc, 128 NULL, 129 }; 130 131 /* string descriptors: */ 132 133 static struct usb_string gser_string_defs[] = { 134 [0].s = "Generic Serial", 135 { } /* end of list */ 136 }; 137 138 static struct usb_gadget_strings gser_string_table = { 139 .language = 0x0409, /* en-us */ 140 .strings = gser_string_defs, 141 }; 142 143 static struct usb_gadget_strings *gser_strings[] = { 144 &gser_string_table, 145 NULL, 146 }; 147 148 /*-------------------------------------------------------------------------*/ 149 150 static int gser_set_alt(struct usb_function *f, unsigned intf, unsigned alt) 151 { 152 struct f_gser *gser = func_to_gser(f); 153 struct usb_composite_dev *cdev = f->config->cdev; 154 155 /* we know alt == 0, so this is an activation or a reset */ 156 157 if (gser->port.in->enabled) { 158 dev_dbg(&cdev->gadget->dev, 159 "reset generic ttyGS%d\n", gser->port_num); 160 gserial_disconnect(&gser->port); 161 } 162 if (!gser->port.in->desc || !gser->port.out->desc) { 163 dev_dbg(&cdev->gadget->dev, 164 "activate generic ttyGS%d\n", gser->port_num); 165 if (config_ep_by_speed(cdev->gadget, f, gser->port.in) || 166 config_ep_by_speed(cdev->gadget, f, gser->port.out)) { 167 gser->port.in->desc = NULL; 168 gser->port.out->desc = NULL; 169 return -EINVAL; 170 } 171 } 172 gserial_connect(&gser->port, gser->port_num); 173 return 0; 174 } 175 176 static void gser_disable(struct usb_function *f) 177 { 178 struct f_gser *gser = func_to_gser(f); 179 struct usb_composite_dev *cdev = f->config->cdev; 180 181 dev_dbg(&cdev->gadget->dev, 182 "generic ttyGS%d deactivated\n", gser->port_num); 183 gserial_disconnect(&gser->port); 184 } 185 186 /*-------------------------------------------------------------------------*/ 187 188 /* serial function driver setup/binding */ 189 190 static int gser_bind(struct usb_configuration *c, struct usb_function *f) 191 { 192 struct usb_composite_dev *cdev = c->cdev; 193 struct f_gser *gser = func_to_gser(f); 194 int status; 195 struct usb_ep *ep; 196 197 /* REVISIT might want instance-specific strings to help 198 * distinguish instances ... 199 */ 200 201 /* maybe allocate device-global string ID */ 202 if (gser_string_defs[0].id == 0) { 203 status = usb_string_id(c->cdev); 204 if (status < 0) 205 return status; 206 gser_string_defs[0].id = status; 207 } 208 209 /* allocate instance-specific interface IDs */ 210 status = usb_interface_id(c, f); 211 if (status < 0) 212 goto fail; 213 gser->data_id = status; 214 gser_interface_desc.bInterfaceNumber = status; 215 216 status = -ENODEV; 217 218 /* allocate instance-specific endpoints */ 219 ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_in_desc); 220 if (!ep) 221 goto fail; 222 gser->port.in = ep; 223 224 ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_out_desc); 225 if (!ep) 226 goto fail; 227 gser->port.out = ep; 228 229 /* support all relevant hardware speeds... we expect that when 230 * hardware is dual speed, all bulk-capable endpoints work at 231 * both speeds 232 */ 233 gser_hs_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress; 234 gser_hs_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress; 235 236 gser_ss_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress; 237 gser_ss_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress; 238 239 status = usb_assign_descriptors(f, gser_fs_function, gser_hs_function, 240 gser_ss_function, NULL); 241 if (status) 242 goto fail; 243 dev_dbg(&cdev->gadget->dev, "generic ttyGS%d: %s speed IN/%s OUT/%s\n", 244 gser->port_num, 245 gadget_is_superspeed(c->cdev->gadget) ? "super" : 246 gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full", 247 gser->port.in->name, gser->port.out->name); 248 return 0; 249 250 fail: 251 ERROR(cdev, "%s: can't bind, err %d\n", f->name, status); 252 253 return status; 254 } 255 256 static inline struct f_serial_opts *to_f_serial_opts(struct config_item *item) 257 { 258 return container_of(to_config_group(item), struct f_serial_opts, 259 func_inst.group); 260 } 261 262 static void serial_attr_release(struct config_item *item) 263 { 264 struct f_serial_opts *opts = to_f_serial_opts(item); 265 266 usb_put_function_instance(&opts->func_inst); 267 } 268 269 static struct configfs_item_operations serial_item_ops = { 270 .release = serial_attr_release, 271 }; 272 273 static ssize_t f_serial_port_num_show(struct config_item *item, char *page) 274 { 275 return sprintf(page, "%u\n", to_f_serial_opts(item)->port_num); 276 } 277 278 CONFIGFS_ATTR_RO(f_serial_, port_num); 279 280 static struct configfs_attribute *acm_attrs[] = { 281 &f_serial_attr_port_num, 282 NULL, 283 }; 284 285 static struct config_item_type serial_func_type = { 286 .ct_item_ops = &serial_item_ops, 287 .ct_attrs = acm_attrs, 288 .ct_owner = THIS_MODULE, 289 }; 290 291 static void gser_free_inst(struct usb_function_instance *f) 292 { 293 struct f_serial_opts *opts; 294 295 opts = container_of(f, struct f_serial_opts, func_inst); 296 gserial_free_line(opts->port_num); 297 kfree(opts); 298 } 299 300 static struct usb_function_instance *gser_alloc_inst(void) 301 { 302 struct f_serial_opts *opts; 303 int ret; 304 305 opts = kzalloc(sizeof(*opts), GFP_KERNEL); 306 if (!opts) 307 return ERR_PTR(-ENOMEM); 308 309 opts->func_inst.free_func_inst = gser_free_inst; 310 ret = gserial_alloc_line(&opts->port_num); 311 if (ret) { 312 kfree(opts); 313 return ERR_PTR(ret); 314 } 315 config_group_init_type_name(&opts->func_inst.group, "", 316 &serial_func_type); 317 318 return &opts->func_inst; 319 } 320 321 static void gser_free(struct usb_function *f) 322 { 323 struct f_gser *serial; 324 325 serial = func_to_gser(f); 326 kfree(serial); 327 } 328 329 static void gser_unbind(struct usb_configuration *c, struct usb_function *f) 330 { 331 usb_free_all_descriptors(f); 332 } 333 334 static struct usb_function *gser_alloc(struct usb_function_instance *fi) 335 { 336 struct f_gser *gser; 337 struct f_serial_opts *opts; 338 339 /* allocate and initialize one new instance */ 340 gser = kzalloc(sizeof(*gser), GFP_KERNEL); 341 if (!gser) 342 return ERR_PTR(-ENOMEM); 343 344 opts = container_of(fi, struct f_serial_opts, func_inst); 345 346 gser->port_num = opts->port_num; 347 348 gser->port.func.name = "gser"; 349 gser->port.func.strings = gser_strings; 350 gser->port.func.bind = gser_bind; 351 gser->port.func.unbind = gser_unbind; 352 gser->port.func.set_alt = gser_set_alt; 353 gser->port.func.disable = gser_disable; 354 gser->port.func.free_func = gser_free; 355 356 return &gser->port.func; 357 } 358 359 DECLARE_USB_FUNCTION_INIT(gser, gser_alloc_inst, gser_alloc); 360 MODULE_LICENSE("GPL"); 361 MODULE_AUTHOR("Al Borchers"); 362 MODULE_AUTHOR("David Brownell"); 363