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