Greg Kroah-Hartman | 79c822b | 2014-08-15 16:01:23 +0800 | [diff] [blame] | 1 | /* |
| 2 | * I2C bridge driver for the Greybus "generic" I2C module. |
| 3 | * |
| 4 | * Copyright 2014 Google Inc. |
| 5 | * |
| 6 | * Released under the GPLv2 only. |
| 7 | */ |
| 8 | |
| 9 | #include <linux/kernel.h> |
| 10 | #include <linux/module.h> |
| 11 | #include <linux/slab.h> |
| 12 | #include <linux/tty.h> |
| 13 | #include <linux/serial.h> |
| 14 | #include <linux/tty_driver.h> |
| 15 | #include <linux/tty_flip.h> |
Greg Kroah-Hartman | ff45c26 | 2014-08-15 18:33:33 +0800 | [diff] [blame] | 16 | #include <linux/idr.h> |
Greg Kroah-Hartman | 79c822b | 2014-08-15 16:01:23 +0800 | [diff] [blame] | 17 | #include "greybus.h" |
| 18 | |
Greg Kroah-Hartman | a18e151 | 2014-08-15 18:54:11 +0800 | [diff] [blame^] | 19 | #define GB_TTY_MAJOR 180 /* FIXME use a real number!!! */ |
| 20 | #define GB_NUM_MINORS 255 /* 255 is enough for anyone... */ |
Greg Kroah-Hartman | 79c822b | 2014-08-15 16:01:23 +0800 | [diff] [blame] | 21 | |
| 22 | struct gb_tty { |
| 23 | struct tty_port port; |
| 24 | struct greybus_device *gdev; |
| 25 | int cport; |
| 26 | unsigned int minor; |
| 27 | unsigned char clocal; |
Greg Kroah-Hartman | a18e151 | 2014-08-15 18:54:11 +0800 | [diff] [blame^] | 28 | unsigned int throttled:1; |
| 29 | unsigned int throttle_req:1; |
| 30 | spinlock_t read_lock; |
| 31 | spinlock_t write_lock; |
Greg Kroah-Hartman | 79c822b | 2014-08-15 16:01:23 +0800 | [diff] [blame] | 32 | // FIXME locking!!! |
| 33 | }; |
| 34 | |
| 35 | static const struct greybus_device_id id_table[] = { |
| 36 | { GREYBUS_DEVICE(0x45, 0x45) }, /* make shit up */ |
| 37 | { }, /* terminating NULL entry */ |
| 38 | }; |
| 39 | |
Greg Kroah-Hartman | ff45c26 | 2014-08-15 18:33:33 +0800 | [diff] [blame] | 40 | static struct tty_driver *gb_tty_driver; |
| 41 | static DEFINE_IDR(tty_minors); |
| 42 | static DEFINE_MUTEX(table_lock); |
| 43 | |
| 44 | static struct gb_tty *get_gb_by_minor(unsigned minor) |
| 45 | { |
| 46 | struct gb_tty *gb_tty; |
| 47 | |
| 48 | mutex_lock(&table_lock); |
| 49 | gb_tty = idr_find(&tty_minors, minor); |
| 50 | mutex_unlock(&table_lock); |
| 51 | return gb_tty; |
| 52 | } |
| 53 | |
| 54 | static int alloc_minor(struct gb_tty *gb_tty) |
| 55 | { |
| 56 | int minor; |
| 57 | |
| 58 | mutex_lock(&table_lock); |
| 59 | minor = idr_alloc(&tty_minors, gb_tty, 0, 0, GFP_KERNEL); |
| 60 | if (minor < 0) |
| 61 | goto error; |
| 62 | gb_tty->minor = minor; |
| 63 | error: |
| 64 | mutex_unlock(&table_lock); |
| 65 | return minor; |
| 66 | } |
| 67 | |
| 68 | static void release_minor(struct gb_tty *gb_tty) |
| 69 | { |
| 70 | mutex_lock(&table_lock); |
| 71 | idr_remove(&tty_minors, gb_tty->minor); |
| 72 | mutex_unlock(&table_lock); |
| 73 | } |
| 74 | |
| 75 | static int gb_tty_install(struct tty_driver *driver, struct tty_struct *tty) |
| 76 | { |
| 77 | struct gb_tty *gb_tty; |
| 78 | int retval; |
| 79 | |
| 80 | gb_tty = get_gb_by_minor(tty->index); |
| 81 | if (!gb_tty) |
| 82 | return -ENODEV; |
| 83 | |
| 84 | retval = tty_standard_install(driver, tty); |
| 85 | if (retval) |
| 86 | goto error; |
| 87 | |
| 88 | tty->driver_data = gb_tty; |
| 89 | return 0; |
| 90 | error: |
| 91 | tty_port_put(&gb_tty->port); |
| 92 | return retval; |
| 93 | } |
| 94 | |
| 95 | static int gb_tty_open(struct tty_struct *tty, struct file *file) |
| 96 | { |
| 97 | struct gb_tty *gb_tty = tty->driver_data; |
| 98 | |
| 99 | return tty_port_open(&gb_tty->port, tty, file); |
| 100 | } |
| 101 | |
| 102 | static void gb_tty_close(struct tty_struct *tty, struct file *file) |
| 103 | { |
| 104 | struct gb_tty *gb_tty = tty->driver_data; |
| 105 | |
| 106 | tty_port_close(&gb_tty->port, tty, file); |
| 107 | } |
| 108 | |
| 109 | static void gb_tty_cleanup(struct tty_struct *tty) |
| 110 | { |
| 111 | struct gb_tty *gb_tty = tty->driver_data; |
| 112 | |
| 113 | tty_port_put(&gb_tty->port); |
| 114 | } |
| 115 | |
| 116 | static void gb_tty_hangup(struct tty_struct *tty) |
| 117 | { |
| 118 | struct gb_tty *gb_tty = tty->driver_data; |
| 119 | |
| 120 | tty_port_hangup(&gb_tty->port); |
| 121 | } |
| 122 | |
Greg Kroah-Hartman | a18e151 | 2014-08-15 18:54:11 +0800 | [diff] [blame^] | 123 | static int gb_tty_write(struct tty_struct *tty, const unsigned char *buf, |
| 124 | int count) |
| 125 | { |
| 126 | struct gb_tty *gb_tty = tty->driver_data; |
| 127 | |
| 128 | // FIXME - actually implement... |
| 129 | |
| 130 | return 0; |
| 131 | } |
| 132 | |
| 133 | static int gb_tty_write_room(struct tty_struct *tty) |
| 134 | { |
| 135 | struct gb_tty *gb_tty = tty->driver_data; |
| 136 | |
| 137 | // FIXME - how much do we want to say we have room for? |
| 138 | return 0; |
| 139 | } |
| 140 | |
| 141 | static int gb_tty_chars_in_buffer(struct tty_struct *tty) |
| 142 | { |
| 143 | struct gb_tty *gb_tty = tty->driver_data; |
| 144 | |
| 145 | // FIXME - how many left to send? |
| 146 | return 0; |
| 147 | } |
| 148 | |
| 149 | static void gb_tty_throttle(struct tty_struct *tty) |
| 150 | { |
| 151 | struct gb_tty *gb_tty = tty->driver_data; |
| 152 | |
| 153 | spin_lock_irq(&gb_tty->read_lock); |
| 154 | gb_tty->throttle_req = 1; |
| 155 | spin_unlock_irq(&gb_tty->read_lock); |
| 156 | } |
| 157 | |
| 158 | static void gb_tty_unthrottle(struct tty_struct *tty) |
| 159 | { |
| 160 | struct gb_tty *gb_tty = tty->driver_data; |
| 161 | unsigned int was_throttled; |
| 162 | |
| 163 | spin_lock_irq(&gb_tty->read_lock); |
| 164 | was_throttled = gb_tty->throttled; |
| 165 | gb_tty->throttle_req = 0; |
| 166 | gb_tty->throttled = 0; |
| 167 | spin_unlock_irq(&gb_tty->read_lock); |
| 168 | |
| 169 | if (was_throttled) { |
| 170 | // FIXME - send more data |
| 171 | } |
| 172 | } |
| 173 | |
Greg Kroah-Hartman | 79c822b | 2014-08-15 16:01:23 +0800 | [diff] [blame] | 174 | |
| 175 | static const struct tty_operations gb_ops = { |
| 176 | .install = gb_tty_install, |
| 177 | .open = gb_tty_open, |
| 178 | .close = gb_tty_close, |
| 179 | .cleanup = gb_tty_cleanup, |
| 180 | .hangup = gb_tty_hangup, |
| 181 | .write = gb_tty_write, |
| 182 | .write_room = gb_tty_write_room, |
| 183 | .ioctl = gb_tty_ioctl, |
| 184 | .throttle = gb_tty_throttle, |
| 185 | .unthrottle = gb_tty_unthrottle, |
| 186 | .chars_in_buffer = gb_tty_chars_in_buffer, |
| 187 | .break_ctl = gb_tty_break_ctl, |
| 188 | .set_termios = gb_tty_set_termios, |
| 189 | .tiocmget = gb_tty_tiocmget, |
| 190 | .tiocmset = gb_tty_tiocmset, |
| 191 | }; |
| 192 | |
Greg Kroah-Hartman | 79c822b | 2014-08-15 16:01:23 +0800 | [diff] [blame] | 193 | |
| 194 | static int tty_gb_probe(struct greybus_device *gdev, const struct greybus_device_id *id) |
| 195 | { |
Greg Kroah-Hartman | a18e151 | 2014-08-15 18:54:11 +0800 | [diff] [blame^] | 196 | struct gb_tty *gb_tty; |
| 197 | struct device *tty_dev; |
Greg Kroah-Hartman | 79c822b | 2014-08-15 16:01:23 +0800 | [diff] [blame] | 198 | int retval; |
Greg Kroah-Hartman | a18e151 | 2014-08-15 18:54:11 +0800 | [diff] [blame^] | 199 | int minor; |
Greg Kroah-Hartman | 79c822b | 2014-08-15 16:01:23 +0800 | [diff] [blame] | 200 | |
Greg Kroah-Hartman | a18e151 | 2014-08-15 18:54:11 +0800 | [diff] [blame^] | 201 | gb_tty = devm_kzalloc(&gdev->dev, sizeof(*gb_tty), GFP_KERNEL); |
| 202 | if (!gb_tty) |
| 203 | return -ENOMEM; |
| 204 | |
| 205 | minor = alloc_minor(gb_tty); |
| 206 | if (minor == GB_NUM_MINORS) { |
| 207 | dev_err(&gdev->dev, "no more free minor numbers\n"); |
| 208 | return -ENODEV; |
| 209 | } |
| 210 | |
| 211 | gb_tty->minor = minor; |
| 212 | gb_tty->gdev = gdev; |
| 213 | spin_lock_init(&gb_tty->write_lock); |
| 214 | spin_lock_init(&gb_tty->read_lock); |
| 215 | |
| 216 | /* FIXME - allocate gb buffers */ |
| 217 | |
| 218 | greybus_set_drvdata(gdev, gb_tty); |
| 219 | |
| 220 | tty_dev = tty_port_register_device(&gb_tty->port, gb_tty_driver, minor, |
| 221 | &gdev->dev); |
| 222 | if (IS_ERR(tty_dev)) { |
| 223 | retval = PTR_ERR(tty_dev); |
| 224 | goto error; |
| 225 | } |
| 226 | |
Greg Kroah-Hartman | 79c822b | 2014-08-15 16:01:23 +0800 | [diff] [blame] | 227 | return 0; |
Greg Kroah-Hartman | a18e151 | 2014-08-15 18:54:11 +0800 | [diff] [blame^] | 228 | error: |
| 229 | release_minor(gb_tty); |
| 230 | return retval; |
Greg Kroah-Hartman | 79c822b | 2014-08-15 16:01:23 +0800 | [diff] [blame] | 231 | } |
| 232 | |
| 233 | static void tty_gb_disconnect(struct greybus_device *gdev) |
| 234 | { |
Greg Kroah-Hartman | a18e151 | 2014-08-15 18:54:11 +0800 | [diff] [blame^] | 235 | struct gb_tty *gb_tty = greybus_get_drvdata(gdev); |
| 236 | struct tty_struct *tty; |
| 237 | |
| 238 | tty = tty_port_tty_get(&gb_tty->port); |
| 239 | if (tty) { |
| 240 | tty_vhangup(tty); |
| 241 | tty_kref_put(tty); |
| 242 | } |
| 243 | /* FIXME - stop all traffic */ |
| 244 | |
| 245 | tty_unregister_device(gb_tty_driver, gb_tty->minor); |
| 246 | |
| 247 | tty_port_put(&gb_tty->port); |
Greg Kroah-Hartman | 79c822b | 2014-08-15 16:01:23 +0800 | [diff] [blame] | 248 | } |
| 249 | |
| 250 | static struct greybus_driver tty_gb_driver = { |
| 251 | .probe = tty_gb_probe, |
| 252 | .disconnect = tty_gb_disconnect, |
| 253 | .id_table = id_table, |
| 254 | }; |
| 255 | |
| 256 | |
| 257 | static int __init gb_tty_init(void) |
| 258 | { |
| 259 | int retval; |
| 260 | |
Greg Kroah-Hartman | a18e151 | 2014-08-15 18:54:11 +0800 | [diff] [blame^] | 261 | gb_tty_driver = alloc_tty_driver(GB_NUM_MINORS); |
Greg Kroah-Hartman | 79c822b | 2014-08-15 16:01:23 +0800 | [diff] [blame] | 262 | if (!gb_tty_driver) |
| 263 | return -ENOMEM; |
| 264 | |
| 265 | gb_tty_driver->driver_name = "gb"; |
| 266 | gb_tty_driver->name = "ttyGB"; |
| 267 | gb_tty_driver->major = GB_TTY_MAJOR; |
| 268 | gb_tty_driver->minor_start = 0; |
| 269 | gb_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; |
| 270 | gb_tty_driver->subtype = SERIAL_TYPE_NORMAL; |
| 271 | gb_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; |
| 272 | gb_tty_driver->init_termios = tty_std_termios; |
| 273 | gb_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL; |
| 274 | tty_set_operations(gb_tty_driver, &gb_ops); |
| 275 | |
| 276 | retval = tty_register_driver(gb_tty_driver); |
| 277 | if (retval) { |
| 278 | put_tty_driver(gb_tty_driver); |
| 279 | return retval; |
| 280 | } |
| 281 | |
| 282 | retval = greybus_register(&tty_gb_driver); |
| 283 | if (retval) { |
| 284 | tty_unregister_driver(gb_tty_driver); |
| 285 | put_tty_driver(gb_tty_driver); |
| 286 | } |
| 287 | return retval; |
| 288 | } |
| 289 | |
| 290 | static void __exit gb_tty_exit(void) |
| 291 | { |
| 292 | greybus_deregister(&tty_gb_driver); |
| 293 | tty_unregister_driver(gb_tty_driver); |
| 294 | put_tty_driver(gb_tty_driver); |
| 295 | } |
| 296 | |
| 297 | module_init(gb_tty_init); |
| 298 | module_exit(gb_tty_exit); |
| 299 | MODULE_LICENSE("GPL"); |
| 300 | MODULE_AUTHOR("Greg Kroah-Hartman <gregkh@linuxfoundation.org>"); |