Niranjana Vishwanathapura | daaf6ff | 2011-02-09 11:16:34 -0800 | [diff] [blame] | 1 | /* drivers/tty/serial/msm_smd_tty.c |
| 2 | * |
| 3 | * Copyright (C) 2007 Google, Inc. |
| 4 | * Copyright (c) 2011, Code Aurora Forum. All rights reserved. |
| 5 | * Author: Brian Swetland <swetland@google.com> |
| 6 | * |
| 7 | * This software is licensed under the terms of the GNU General Public |
| 8 | * License version 2, as published by the Free Software Foundation, and |
| 9 | * may be copied, distributed, and modified under those terms. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | */ |
| 17 | |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/fs.h> |
| 20 | #include <linux/cdev.h> |
| 21 | #include <linux/device.h> |
| 22 | #include <linux/wait.h> |
| 23 | |
| 24 | #include <linux/tty.h> |
| 25 | #include <linux/tty_driver.h> |
| 26 | #include <linux/tty_flip.h> |
| 27 | |
| 28 | #include <mach/msm_smd.h> |
| 29 | |
| 30 | #define MAX_SMD_TTYS 32 |
| 31 | |
| 32 | struct smd_tty_info { |
| 33 | struct tty_port port; |
| 34 | smd_channel_t *ch; |
| 35 | }; |
| 36 | |
| 37 | struct smd_tty_channel_desc { |
| 38 | int id; |
| 39 | const char *name; |
| 40 | }; |
| 41 | |
| 42 | static struct smd_tty_info smd_tty[MAX_SMD_TTYS]; |
| 43 | |
| 44 | static const struct smd_tty_channel_desc smd_default_tty_channels[] = { |
| 45 | { .id = 0, .name = "SMD_DS" }, |
| 46 | { .id = 27, .name = "SMD_GPSNMEA" }, |
| 47 | }; |
| 48 | |
| 49 | static const struct smd_tty_channel_desc *smd_tty_channels = |
| 50 | smd_default_tty_channels; |
| 51 | static int smd_tty_channels_len = ARRAY_SIZE(smd_default_tty_channels); |
| 52 | |
| 53 | static void smd_tty_notify(void *priv, unsigned event) |
| 54 | { |
| 55 | unsigned char *ptr; |
| 56 | int avail; |
| 57 | struct smd_tty_info *info = priv; |
| 58 | struct tty_struct *tty; |
| 59 | |
| 60 | if (event != SMD_EVENT_DATA) |
| 61 | return; |
| 62 | |
| 63 | tty = tty_port_tty_get(&info->port); |
| 64 | if (!tty) |
| 65 | return; |
| 66 | |
| 67 | for (;;) { |
| 68 | if (test_bit(TTY_THROTTLED, &tty->flags)) |
| 69 | break; |
| 70 | avail = smd_read_avail(info->ch); |
| 71 | if (avail == 0) |
| 72 | break; |
| 73 | |
| 74 | avail = tty_prepare_flip_string(tty, &ptr, avail); |
| 75 | |
| 76 | if (smd_read(info->ch, ptr, avail) != avail) { |
| 77 | /* shouldn't be possible since we're in interrupt |
| 78 | ** context here and nobody else could 'steal' our |
| 79 | ** characters. |
| 80 | */ |
| 81 | pr_err("OOPS - smd_tty_buffer mismatch?!"); |
| 82 | } |
| 83 | |
| 84 | tty_flip_buffer_push(tty); |
| 85 | } |
| 86 | |
| 87 | /* XXX only when writable and necessary */ |
| 88 | tty_wakeup(tty); |
| 89 | tty_kref_put(tty); |
| 90 | } |
| 91 | |
| 92 | static int smd_tty_port_activate(struct tty_port *tport, struct tty_struct *tty) |
| 93 | { |
| 94 | int i, res = 0; |
| 95 | int n = tty->index; |
| 96 | const char *name = NULL; |
| 97 | struct smd_tty_info *info = smd_tty + n; |
| 98 | |
| 99 | for (i = 0; i < smd_tty_channels_len; i++) { |
| 100 | if (smd_tty_channels[i].id == n) { |
| 101 | name = smd_tty_channels[i].name; |
| 102 | break; |
| 103 | } |
| 104 | } |
| 105 | if (!name) |
| 106 | return -ENODEV; |
| 107 | |
| 108 | if (info->ch) |
| 109 | smd_kick(info->ch); |
| 110 | else |
| 111 | res = smd_open(name, &info->ch, info, smd_tty_notify); |
| 112 | |
| 113 | if (!res) |
| 114 | tty->driver_data = info; |
| 115 | |
| 116 | return res; |
| 117 | } |
| 118 | |
| 119 | static void smd_tty_port_shutdown(struct tty_port *tport) |
| 120 | { |
| 121 | struct smd_tty_info *info; |
| 122 | struct tty_struct *tty = tty_port_tty_get(tport); |
| 123 | |
| 124 | info = tty->driver_data; |
| 125 | if (info->ch) { |
| 126 | smd_close(info->ch); |
| 127 | info->ch = 0; |
| 128 | } |
| 129 | |
| 130 | tty->driver_data = 0; |
| 131 | tty_kref_put(tty); |
| 132 | } |
| 133 | |
| 134 | static int smd_tty_open(struct tty_struct *tty, struct file *f) |
| 135 | { |
| 136 | struct smd_tty_info *info = smd_tty + tty->index; |
| 137 | |
| 138 | return tty_port_open(&info->port, tty, f); |
| 139 | } |
| 140 | |
| 141 | static void smd_tty_close(struct tty_struct *tty, struct file *f) |
| 142 | { |
| 143 | struct smd_tty_info *info = tty->driver_data; |
| 144 | |
| 145 | tty_port_close(&info->port, tty, f); |
| 146 | } |
| 147 | |
| 148 | static int smd_tty_write(struct tty_struct *tty, |
| 149 | const unsigned char *buf, int len) |
| 150 | { |
| 151 | struct smd_tty_info *info = tty->driver_data; |
| 152 | int avail; |
| 153 | |
| 154 | /* if we're writing to a packet channel we will |
| 155 | ** never be able to write more data than there |
| 156 | ** is currently space for |
| 157 | */ |
| 158 | avail = smd_write_avail(info->ch); |
| 159 | if (len > avail) |
| 160 | len = avail; |
| 161 | |
| 162 | return smd_write(info->ch, buf, len); |
| 163 | } |
| 164 | |
| 165 | static int smd_tty_write_room(struct tty_struct *tty) |
| 166 | { |
| 167 | struct smd_tty_info *info = tty->driver_data; |
| 168 | return smd_write_avail(info->ch); |
| 169 | } |
| 170 | |
| 171 | static int smd_tty_chars_in_buffer(struct tty_struct *tty) |
| 172 | { |
| 173 | struct smd_tty_info *info = tty->driver_data; |
| 174 | return smd_read_avail(info->ch); |
| 175 | } |
| 176 | |
| 177 | static void smd_tty_unthrottle(struct tty_struct *tty) |
| 178 | { |
| 179 | struct smd_tty_info *info = tty->driver_data; |
| 180 | smd_kick(info->ch); |
| 181 | } |
| 182 | |
| 183 | static const struct tty_port_operations smd_tty_port_ops = { |
| 184 | .shutdown = smd_tty_port_shutdown, |
| 185 | .activate = smd_tty_port_activate, |
| 186 | }; |
| 187 | |
| 188 | static const struct tty_operations smd_tty_ops = { |
| 189 | .open = smd_tty_open, |
| 190 | .close = smd_tty_close, |
| 191 | .write = smd_tty_write, |
| 192 | .write_room = smd_tty_write_room, |
| 193 | .chars_in_buffer = smd_tty_chars_in_buffer, |
| 194 | .unthrottle = smd_tty_unthrottle, |
| 195 | }; |
| 196 | |
| 197 | static struct tty_driver *smd_tty_driver; |
| 198 | |
| 199 | static int __init smd_tty_init(void) |
| 200 | { |
| 201 | int ret, i; |
| 202 | |
| 203 | smd_tty_driver = alloc_tty_driver(MAX_SMD_TTYS); |
| 204 | if (smd_tty_driver == 0) |
| 205 | return -ENOMEM; |
| 206 | |
| 207 | smd_tty_driver->owner = THIS_MODULE; |
| 208 | smd_tty_driver->driver_name = "smd_tty_driver"; |
| 209 | smd_tty_driver->name = "smd"; |
| 210 | smd_tty_driver->major = 0; |
| 211 | smd_tty_driver->minor_start = 0; |
| 212 | smd_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; |
| 213 | smd_tty_driver->subtype = SERIAL_TYPE_NORMAL; |
| 214 | smd_tty_driver->init_termios = tty_std_termios; |
| 215 | smd_tty_driver->init_termios.c_iflag = 0; |
| 216 | smd_tty_driver->init_termios.c_oflag = 0; |
| 217 | smd_tty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; |
| 218 | smd_tty_driver->init_termios.c_lflag = 0; |
| 219 | smd_tty_driver->flags = TTY_DRIVER_RESET_TERMIOS | |
| 220 | TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; |
| 221 | tty_set_operations(smd_tty_driver, &smd_tty_ops); |
| 222 | |
| 223 | ret = tty_register_driver(smd_tty_driver); |
| 224 | if (ret) |
| 225 | return ret; |
| 226 | |
| 227 | for (i = 0; i < smd_tty_channels_len; i++) { |
| 228 | tty_port_init(&smd_tty[smd_tty_channels[i].id].port); |
| 229 | smd_tty[smd_tty_channels[i].id].port.ops = &smd_tty_port_ops; |
| 230 | tty_register_device(smd_tty_driver, smd_tty_channels[i].id, 0); |
| 231 | } |
| 232 | |
| 233 | return 0; |
| 234 | } |
| 235 | |
| 236 | module_init(smd_tty_init); |