Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Tty buffer allocation management |
| 3 | */ |
| 4 | |
| 5 | #include <linux/types.h> |
| 6 | #include <linux/errno.h> |
| 7 | #include <linux/tty.h> |
| 8 | #include <linux/tty_driver.h> |
| 9 | #include <linux/tty_flip.h> |
| 10 | #include <linux/timer.h> |
| 11 | #include <linux/string.h> |
| 12 | #include <linux/slab.h> |
| 13 | #include <linux/sched.h> |
| 14 | #include <linux/init.h> |
| 15 | #include <linux/wait.h> |
| 16 | #include <linux/bitops.h> |
| 17 | #include <linux/delay.h> |
| 18 | #include <linux/module.h> |
George Spelvin | 593fb1ae4 | 2013-02-12 02:00:43 -0500 | [diff] [blame] | 19 | #include <linux/ratelimit.h> |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 20 | |
Peter Hurley | 1cef50e | 2013-06-15 09:36:02 -0400 | [diff] [blame] | 21 | |
| 22 | #define MIN_TTYB_SIZE 256 |
| 23 | #define TTYB_ALIGN_MASK 255 |
| 24 | |
Peter Hurley | 7bfe0b7 | 2013-06-15 09:36:08 -0400 | [diff] [blame^] | 25 | /* |
| 26 | * Byte threshold to limit memory consumption for flip buffers. |
| 27 | * The actual memory limit is > 2x this amount. |
| 28 | */ |
| 29 | #define TTYB_MEM_LIMIT 65536 |
| 30 | |
| 31 | |
| 32 | /** |
| 33 | * tty_buffer_space_avail - return unused buffer space |
| 34 | * @port - tty_port owning the flip buffer |
| 35 | * |
| 36 | * Returns the # of bytes which can be written by the driver without |
| 37 | * reaching the buffer limit. |
| 38 | * |
| 39 | * Note: this does not guarantee that memory is available to write |
| 40 | * the returned # of bytes (use tty_prepare_flip_string_xxx() to |
| 41 | * pre-allocate if memory guarantee is required). |
| 42 | */ |
| 43 | |
| 44 | int tty_buffer_space_avail(struct tty_port *port) |
| 45 | { |
| 46 | int space = TTYB_MEM_LIMIT - atomic_read(&port->buf.memory_used); |
| 47 | return max(space, 0); |
| 48 | } |
| 49 | |
Peter Hurley | 9dd5139 | 2013-06-15 09:36:03 -0400 | [diff] [blame] | 50 | static void tty_buffer_reset(struct tty_buffer *p, size_t size) |
| 51 | { |
| 52 | p->used = 0; |
| 53 | p->size = size; |
| 54 | p->next = NULL; |
| 55 | p->commit = 0; |
| 56 | p->read = 0; |
| 57 | } |
| 58 | |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 59 | /** |
| 60 | * tty_buffer_free_all - free buffers used by a tty |
| 61 | * @tty: tty to free from |
| 62 | * |
| 63 | * Remove all the buffers pending on a tty whether queued with data |
| 64 | * or in the free ring. Must be called when the tty is no longer in use |
| 65 | * |
| 66 | * Locking: none |
| 67 | */ |
| 68 | |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 69 | void tty_buffer_free_all(struct tty_port *port) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 70 | { |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 71 | struct tty_bufhead *buf = &port->buf; |
Peter Hurley | 809850b | 2013-06-15 09:36:06 -0400 | [diff] [blame] | 72 | struct tty_buffer *p, *next; |
| 73 | struct llist_node *llist; |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 74 | |
Peter Hurley | 2cf7b67 | 2013-06-15 09:36:05 -0400 | [diff] [blame] | 75 | while ((p = buf->head) != NULL) { |
| 76 | buf->head = p->next; |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 77 | if (p->size > 0) |
| 78 | kfree(p); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 79 | } |
Peter Hurley | 809850b | 2013-06-15 09:36:06 -0400 | [diff] [blame] | 80 | llist = llist_del_all(&buf->free); |
| 81 | llist_for_each_entry_safe(p, next, llist, free) |
Peter Hurley | 2cf7b67 | 2013-06-15 09:36:05 -0400 | [diff] [blame] | 82 | kfree(p); |
Peter Hurley | 809850b | 2013-06-15 09:36:06 -0400 | [diff] [blame] | 83 | |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 84 | tty_buffer_reset(&buf->sentinel, 0); |
| 85 | buf->head = &buf->sentinel; |
| 86 | buf->tail = &buf->sentinel; |
Peter Hurley | 7bfe0b7 | 2013-06-15 09:36:08 -0400 | [diff] [blame^] | 87 | |
| 88 | atomic_set(&buf->memory_used, 0); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 89 | } |
| 90 | |
| 91 | /** |
| 92 | * tty_buffer_alloc - allocate a tty buffer |
| 93 | * @tty: tty device |
| 94 | * @size: desired size (characters) |
| 95 | * |
| 96 | * Allocate a new tty buffer to hold the desired number of characters. |
Peter Hurley | 11b9faa | 2013-06-15 09:36:04 -0400 | [diff] [blame] | 97 | * We round our buffers off in 256 character chunks to get better |
| 98 | * allocation behaviour. |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 99 | * Return NULL if out of memory or the allocation would exceed the |
| 100 | * per device queue |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 101 | */ |
| 102 | |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 103 | static struct tty_buffer *tty_buffer_alloc(struct tty_port *port, size_t size) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 104 | { |
Peter Hurley | 809850b | 2013-06-15 09:36:06 -0400 | [diff] [blame] | 105 | struct llist_node *free; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 106 | struct tty_buffer *p; |
| 107 | |
Peter Hurley | 11b9faa | 2013-06-15 09:36:04 -0400 | [diff] [blame] | 108 | /* Round the buffer size out */ |
| 109 | size = __ALIGN_MASK(size, TTYB_ALIGN_MASK); |
| 110 | |
| 111 | if (size <= MIN_TTYB_SIZE) { |
Peter Hurley | 809850b | 2013-06-15 09:36:06 -0400 | [diff] [blame] | 112 | free = llist_del_first(&port->buf.free); |
| 113 | if (free) { |
| 114 | p = llist_entry(free, struct tty_buffer, free); |
Peter Hurley | 11b9faa | 2013-06-15 09:36:04 -0400 | [diff] [blame] | 115 | goto found; |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | /* Should possibly check if this fails for the largest buffer we |
| 120 | have queued and recycle that ? */ |
Peter Hurley | 7bfe0b7 | 2013-06-15 09:36:08 -0400 | [diff] [blame^] | 121 | if (atomic_read(&port->buf.memory_used) > TTYB_MEM_LIMIT) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 122 | return NULL; |
| 123 | p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); |
| 124 | if (p == NULL) |
| 125 | return NULL; |
Peter Hurley | 9dd5139 | 2013-06-15 09:36:03 -0400 | [diff] [blame] | 126 | |
Peter Hurley | 11b9faa | 2013-06-15 09:36:04 -0400 | [diff] [blame] | 127 | found: |
Peter Hurley | 9dd5139 | 2013-06-15 09:36:03 -0400 | [diff] [blame] | 128 | tty_buffer_reset(p, size); |
Peter Hurley | 7bfe0b7 | 2013-06-15 09:36:08 -0400 | [diff] [blame^] | 129 | atomic_add(size, &port->buf.memory_used); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 130 | return p; |
| 131 | } |
| 132 | |
| 133 | /** |
| 134 | * tty_buffer_free - free a tty buffer |
| 135 | * @tty: tty owning the buffer |
| 136 | * @b: the buffer to free |
| 137 | * |
| 138 | * Free a tty buffer, or add it to the free list according to our |
| 139 | * internal strategy |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 140 | */ |
| 141 | |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 142 | static void tty_buffer_free(struct tty_port *port, struct tty_buffer *b) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 143 | { |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 144 | struct tty_bufhead *buf = &port->buf; |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 145 | |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 146 | /* Dumb strategy for now - should keep some stats */ |
Peter Hurley | 7bfe0b7 | 2013-06-15 09:36:08 -0400 | [diff] [blame^] | 147 | WARN_ON(atomic_sub_return(b->size, &buf->memory_used) < 0); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 148 | |
Peter Hurley | 1cef50e | 2013-06-15 09:36:02 -0400 | [diff] [blame] | 149 | if (b->size > MIN_TTYB_SIZE) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 150 | kfree(b); |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 151 | else if (b->size > 0) |
Peter Hurley | 809850b | 2013-06-15 09:36:06 -0400 | [diff] [blame] | 152 | llist_add(&b->free, &buf->free); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 153 | } |
| 154 | |
| 155 | /** |
| 156 | * __tty_buffer_flush - flush full tty buffers |
| 157 | * @tty: tty to flush |
| 158 | * |
| 159 | * flush all the buffers containing receive data. Caller must |
| 160 | * hold the buffer lock and must have ensured no parallel flush to |
| 161 | * ldisc is running. |
| 162 | * |
| 163 | * Locking: Caller must hold tty->buf.lock |
| 164 | */ |
| 165 | |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 166 | static void __tty_buffer_flush(struct tty_port *port) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 167 | { |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 168 | struct tty_bufhead *buf = &port->buf; |
Peter Hurley | 2cf7b67 | 2013-06-15 09:36:05 -0400 | [diff] [blame] | 169 | struct tty_buffer *next; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 170 | |
Peter Hurley | 2cf7b67 | 2013-06-15 09:36:05 -0400 | [diff] [blame] | 171 | while ((next = buf->head->next) != NULL) { |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 172 | tty_buffer_free(port, buf->head); |
Peter Hurley | 2cf7b67 | 2013-06-15 09:36:05 -0400 | [diff] [blame] | 173 | buf->head = next; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 174 | } |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 175 | WARN_ON(buf->head != buf->tail); |
| 176 | buf->head->read = buf->head->commit; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 177 | } |
| 178 | |
| 179 | /** |
| 180 | * tty_buffer_flush - flush full tty buffers |
| 181 | * @tty: tty to flush |
| 182 | * |
| 183 | * flush all the buffers containing receive data. If the buffer is |
| 184 | * being processed by flush_to_ldisc then we defer the processing |
| 185 | * to that function |
| 186 | * |
| 187 | * Locking: none |
| 188 | */ |
| 189 | |
| 190 | void tty_buffer_flush(struct tty_struct *tty) |
| 191 | { |
Jiri Slaby | 2fc2066 | 2012-10-18 22:26:44 +0200 | [diff] [blame] | 192 | struct tty_port *port = tty->port; |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 193 | struct tty_bufhead *buf = &port->buf; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 194 | unsigned long flags; |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 195 | |
| 196 | spin_lock_irqsave(&buf->lock, flags); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 197 | |
| 198 | /* If the data is being pushed to the tty layer then we can't |
| 199 | process it here. Instead set a flag and the flush_to_ldisc |
| 200 | path will process the flush request before it exits */ |
Jiri Slaby | 2fc2066 | 2012-10-18 22:26:44 +0200 | [diff] [blame] | 201 | if (test_bit(TTYP_FLUSHING, &port->iflags)) { |
| 202 | set_bit(TTYP_FLUSHPENDING, &port->iflags); |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 203 | spin_unlock_irqrestore(&buf->lock, flags); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 204 | wait_event(tty->read_wait, |
Jiri Slaby | 2fc2066 | 2012-10-18 22:26:44 +0200 | [diff] [blame] | 205 | test_bit(TTYP_FLUSHPENDING, &port->iflags) == 0); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 206 | return; |
| 207 | } else |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 208 | __tty_buffer_flush(port); |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 209 | spin_unlock_irqrestore(&buf->lock, flags); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 210 | } |
| 211 | |
| 212 | /** |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 213 | * tty_buffer_request_room - grow tty buffer if needed |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 214 | * @tty: tty structure |
| 215 | * @size: size desired |
| 216 | * |
| 217 | * Make at least size bytes of linear space available for the tty |
| 218 | * buffer. If we fail return the size we managed to find. |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 219 | * |
| 220 | * Locking: Takes port->buf.lock |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 221 | */ |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 222 | int tty_buffer_request_room(struct tty_port *port, size_t size) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 223 | { |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 224 | struct tty_bufhead *buf = &port->buf; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 225 | struct tty_buffer *b, *n; |
| 226 | int left; |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 227 | unsigned long flags; |
| 228 | spin_lock_irqsave(&buf->lock, flags); |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 229 | b = buf->tail; |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 230 | left = b->size - b->used; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 231 | |
| 232 | if (left < size) { |
| 233 | /* This is the slow path - looking for new buffers to use */ |
Peter Hurley | 11b9faa | 2013-06-15 09:36:04 -0400 | [diff] [blame] | 234 | if ((n = tty_buffer_alloc(port, size)) != NULL) { |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 235 | b->next = n; |
| 236 | b->commit = b->used; |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 237 | buf->tail = n; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 238 | } else |
| 239 | size = left; |
| 240 | } |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 241 | spin_unlock_irqrestore(&buf->lock, flags); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 242 | return size; |
| 243 | } |
| 244 | EXPORT_SYMBOL_GPL(tty_buffer_request_room); |
| 245 | |
| 246 | /** |
Alan Cox | 2832fc1 | 2010-02-18 16:43:54 +0000 | [diff] [blame] | 247 | * tty_insert_flip_string_fixed_flag - Add characters to the tty buffer |
Jiri Slaby | 2f69335 | 2013-01-03 15:53:02 +0100 | [diff] [blame] | 248 | * @port: tty port |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 249 | * @chars: characters |
Alan Cox | 2832fc1 | 2010-02-18 16:43:54 +0000 | [diff] [blame] | 250 | * @flag: flag value for each character |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 251 | * @size: size |
| 252 | * |
| 253 | * Queue a series of bytes to the tty buffering. All the characters |
Johan Hovold | ccc5ca8 | 2010-05-07 19:58:32 +0200 | [diff] [blame] | 254 | * passed are marked with the supplied flag. Returns the number added. |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 255 | * |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 256 | * Locking: Called functions may take port->buf.lock |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 257 | */ |
| 258 | |
Jiri Slaby | 2f69335 | 2013-01-03 15:53:02 +0100 | [diff] [blame] | 259 | int tty_insert_flip_string_fixed_flag(struct tty_port *port, |
Alan Cox | 2832fc1 | 2010-02-18 16:43:54 +0000 | [diff] [blame] | 260 | const unsigned char *chars, char flag, size_t size) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 261 | { |
| 262 | int copied = 0; |
| 263 | do { |
Fang Wenqi | d4bee0a | 2010-03-09 18:54:28 +0800 | [diff] [blame] | 264 | int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE); |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 265 | int space = tty_buffer_request_room(port, goal); |
| 266 | struct tty_buffer *tb = port->buf.tail; |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 267 | if (unlikely(space == 0)) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 268 | break; |
Peter Hurley | 1fc359f | 2013-06-15 09:36:01 -0400 | [diff] [blame] | 269 | memcpy(char_buf_ptr(tb, tb->used), chars, space); |
| 270 | memset(flag_buf_ptr(tb, tb->used), flag, space); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 271 | tb->used += space; |
| 272 | copied += space; |
| 273 | chars += space; |
| 274 | /* There is a small chance that we need to split the data over |
| 275 | several buffers. If this is the case we must loop */ |
| 276 | } while (unlikely(size > copied)); |
| 277 | return copied; |
| 278 | } |
Alan Cox | 2832fc1 | 2010-02-18 16:43:54 +0000 | [diff] [blame] | 279 | EXPORT_SYMBOL(tty_insert_flip_string_fixed_flag); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 280 | |
| 281 | /** |
| 282 | * tty_insert_flip_string_flags - Add characters to the tty buffer |
Jiri Slaby | 2f69335 | 2013-01-03 15:53:02 +0100 | [diff] [blame] | 283 | * @port: tty port |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 284 | * @chars: characters |
| 285 | * @flags: flag bytes |
| 286 | * @size: size |
| 287 | * |
| 288 | * Queue a series of bytes to the tty buffering. For each character |
| 289 | * the flags array indicates the status of the character. Returns the |
| 290 | * number added. |
| 291 | * |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 292 | * Locking: Called functions may take port->buf.lock |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 293 | */ |
| 294 | |
Jiri Slaby | 2f69335 | 2013-01-03 15:53:02 +0100 | [diff] [blame] | 295 | int tty_insert_flip_string_flags(struct tty_port *port, |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 296 | const unsigned char *chars, const char *flags, size_t size) |
| 297 | { |
| 298 | int copied = 0; |
| 299 | do { |
Fang Wenqi | d4bee0a | 2010-03-09 18:54:28 +0800 | [diff] [blame] | 300 | int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE); |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 301 | int space = tty_buffer_request_room(port, goal); |
| 302 | struct tty_buffer *tb = port->buf.tail; |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 303 | if (unlikely(space == 0)) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 304 | break; |
Peter Hurley | 1fc359f | 2013-06-15 09:36:01 -0400 | [diff] [blame] | 305 | memcpy(char_buf_ptr(tb, tb->used), chars, space); |
| 306 | memcpy(flag_buf_ptr(tb, tb->used), flags, space); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 307 | tb->used += space; |
| 308 | copied += space; |
| 309 | chars += space; |
| 310 | flags += space; |
| 311 | /* There is a small chance that we need to split the data over |
| 312 | several buffers. If this is the case we must loop */ |
| 313 | } while (unlikely(size > copied)); |
| 314 | return copied; |
| 315 | } |
| 316 | EXPORT_SYMBOL(tty_insert_flip_string_flags); |
| 317 | |
| 318 | /** |
| 319 | * tty_schedule_flip - push characters to ldisc |
Jiri Slaby | 6732c8b | 2013-01-03 15:53:07 +0100 | [diff] [blame] | 320 | * @port: tty port to push from |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 321 | * |
| 322 | * Takes any pending buffers and transfers their ownership to the |
| 323 | * ldisc side of the queue. It then schedules those characters for |
| 324 | * processing by the line discipline. |
Ivo Sieben | cee4ad1 | 2012-09-27 14:02:05 +0200 | [diff] [blame] | 325 | * Note that this function can only be used when the low_latency flag |
| 326 | * is unset. Otherwise the workqueue won't be flushed. |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 327 | * |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 328 | * Locking: Takes port->buf.lock |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 329 | */ |
| 330 | |
Jiri Slaby | 6732c8b | 2013-01-03 15:53:07 +0100 | [diff] [blame] | 331 | void tty_schedule_flip(struct tty_port *port) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 332 | { |
Jiri Slaby | 6732c8b | 2013-01-03 15:53:07 +0100 | [diff] [blame] | 333 | struct tty_bufhead *buf = &port->buf; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 334 | unsigned long flags; |
Jiri Slaby | 6732c8b | 2013-01-03 15:53:07 +0100 | [diff] [blame] | 335 | WARN_ON(port->low_latency); |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 336 | |
| 337 | spin_lock_irqsave(&buf->lock, flags); |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 338 | buf->tail->commit = buf->tail->used; |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 339 | spin_unlock_irqrestore(&buf->lock, flags); |
| 340 | schedule_work(&buf->work); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 341 | } |
| 342 | EXPORT_SYMBOL(tty_schedule_flip); |
| 343 | |
| 344 | /** |
| 345 | * tty_prepare_flip_string - make room for characters |
Jiri Slaby | 2f69335 | 2013-01-03 15:53:02 +0100 | [diff] [blame] | 346 | * @port: tty port |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 347 | * @chars: return pointer for character write area |
| 348 | * @size: desired size |
| 349 | * |
| 350 | * Prepare a block of space in the buffer for data. Returns the length |
| 351 | * available and buffer pointer to the space which is now allocated and |
| 352 | * accounted for as ready for normal characters. This is used for drivers |
| 353 | * that need their own block copy routines into the buffer. There is no |
| 354 | * guarantee the buffer is a DMA target! |
| 355 | * |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 356 | * Locking: May call functions taking port->buf.lock |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 357 | */ |
| 358 | |
Jiri Slaby | 2f69335 | 2013-01-03 15:53:02 +0100 | [diff] [blame] | 359 | int tty_prepare_flip_string(struct tty_port *port, unsigned char **chars, |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 360 | size_t size) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 361 | { |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 362 | int space = tty_buffer_request_room(port, size); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 363 | if (likely(space)) { |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 364 | struct tty_buffer *tb = port->buf.tail; |
Peter Hurley | 1fc359f | 2013-06-15 09:36:01 -0400 | [diff] [blame] | 365 | *chars = char_buf_ptr(tb, tb->used); |
| 366 | memset(flag_buf_ptr(tb, tb->used), TTY_NORMAL, space); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 367 | tb->used += space; |
| 368 | } |
| 369 | return space; |
| 370 | } |
| 371 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string); |
| 372 | |
| 373 | /** |
| 374 | * tty_prepare_flip_string_flags - make room for characters |
Jiri Slaby | 2f69335 | 2013-01-03 15:53:02 +0100 | [diff] [blame] | 375 | * @port: tty port |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 376 | * @chars: return pointer for character write area |
| 377 | * @flags: return pointer for status flag write area |
| 378 | * @size: desired size |
| 379 | * |
| 380 | * Prepare a block of space in the buffer for data. Returns the length |
| 381 | * available and buffer pointer to the space which is now allocated and |
| 382 | * accounted for as ready for characters. This is used for drivers |
| 383 | * that need their own block copy routines into the buffer. There is no |
| 384 | * guarantee the buffer is a DMA target! |
| 385 | * |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 386 | * Locking: May call functions taking port->buf.lock |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 387 | */ |
| 388 | |
Jiri Slaby | 2f69335 | 2013-01-03 15:53:02 +0100 | [diff] [blame] | 389 | int tty_prepare_flip_string_flags(struct tty_port *port, |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 390 | unsigned char **chars, char **flags, size_t size) |
| 391 | { |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 392 | int space = tty_buffer_request_room(port, size); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 393 | if (likely(space)) { |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 394 | struct tty_buffer *tb = port->buf.tail; |
Peter Hurley | 1fc359f | 2013-06-15 09:36:01 -0400 | [diff] [blame] | 395 | *chars = char_buf_ptr(tb, tb->used); |
| 396 | *flags = flag_buf_ptr(tb, tb->used); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 397 | tb->used += space; |
| 398 | } |
| 399 | return space; |
| 400 | } |
| 401 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags); |
| 402 | |
| 403 | |
Peter Hurley | da261e7 | 2013-06-15 09:14:14 -0400 | [diff] [blame] | 404 | static int |
| 405 | receive_buf(struct tty_struct *tty, struct tty_buffer *head, int count) |
| 406 | { |
| 407 | struct tty_ldisc *disc = tty->ldisc; |
Peter Hurley | 1fc359f | 2013-06-15 09:36:01 -0400 | [diff] [blame] | 408 | unsigned char *p = char_buf_ptr(head, head->read); |
| 409 | char *f = flag_buf_ptr(head, head->read); |
Peter Hurley | da261e7 | 2013-06-15 09:14:14 -0400 | [diff] [blame] | 410 | |
Peter Hurley | 24a89d1 | 2013-06-15 09:14:15 -0400 | [diff] [blame] | 411 | if (disc->ops->receive_buf2) |
| 412 | count = disc->ops->receive_buf2(tty, p, f, count); |
| 413 | else { |
| 414 | count = min_t(int, count, tty->receive_room); |
| 415 | if (count) |
| 416 | disc->ops->receive_buf(tty, p, f, count); |
| 417 | } |
Peter Hurley | da261e7 | 2013-06-15 09:14:14 -0400 | [diff] [blame] | 418 | head->read += count; |
| 419 | return count; |
| 420 | } |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 421 | |
| 422 | /** |
| 423 | * flush_to_ldisc |
| 424 | * @work: tty structure passed from work queue. |
| 425 | * |
| 426 | * This routine is called out of the software interrupt to flush data |
| 427 | * from the buffer chain to the line discipline. |
| 428 | * |
| 429 | * Locking: holds tty->buf.lock to guard buffer list. Drops the lock |
| 430 | * while invoking the line discipline receive_buf method. The |
| 431 | * receive_buf method is single threaded for each tty instance. |
| 432 | */ |
| 433 | |
| 434 | static void flush_to_ldisc(struct work_struct *work) |
| 435 | { |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 436 | struct tty_port *port = container_of(work, struct tty_port, buf.work); |
| 437 | struct tty_bufhead *buf = &port->buf; |
| 438 | struct tty_struct *tty; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 439 | unsigned long flags; |
| 440 | struct tty_ldisc *disc; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 441 | |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 442 | tty = port->itty; |
Jiri Slaby | 34dcfb8 | 2013-02-27 22:30:24 +0100 | [diff] [blame] | 443 | if (tty == NULL) |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 444 | return; |
| 445 | |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 446 | disc = tty_ldisc_ref(tty); |
Peter Hurley | 3669752 | 2013-06-15 07:04:48 -0400 | [diff] [blame] | 447 | if (disc == NULL) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 448 | return; |
| 449 | |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 450 | spin_lock_irqsave(&buf->lock, flags); |
Linus Torvalds | 4524200 | 2009-10-14 08:59:49 -0700 | [diff] [blame] | 451 | |
Jiri Slaby | 2fc2066 | 2012-10-18 22:26:44 +0200 | [diff] [blame] | 452 | if (!test_and_set_bit(TTYP_FLUSHING, &port->iflags)) { |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 453 | while (1) { |
| 454 | struct tty_buffer *head = buf->head; |
Linus Torvalds | 4524200 | 2009-10-14 08:59:49 -0700 | [diff] [blame] | 455 | int count; |
Linus Torvalds | 4524200 | 2009-10-14 08:59:49 -0700 | [diff] [blame] | 456 | |
| 457 | count = head->commit - head->read; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 458 | if (!count) { |
| 459 | if (head->next == NULL) |
| 460 | break; |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 461 | buf->head = head->next; |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 462 | tty_buffer_free(port, head); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 463 | continue; |
| 464 | } |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 465 | spin_unlock_irqrestore(&buf->lock, flags); |
Peter Hurley | da261e7 | 2013-06-15 09:14:14 -0400 | [diff] [blame] | 466 | |
| 467 | count = receive_buf(tty, head, count); |
| 468 | |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 469 | spin_lock_irqsave(&buf->lock, flags); |
Peter Hurley | 39f610e | 2013-03-20 13:20:43 -0400 | [diff] [blame] | 470 | /* Ldisc or user is trying to flush the buffers. |
| 471 | We may have a deferred request to flush the |
| 472 | input buffer, if so pull the chain under the lock |
| 473 | and empty the queue */ |
| 474 | if (test_bit(TTYP_FLUSHPENDING, &port->iflags)) { |
| 475 | __tty_buffer_flush(port); |
| 476 | clear_bit(TTYP_FLUSHPENDING, &port->iflags); |
| 477 | wake_up(&tty->read_wait); |
| 478 | break; |
Peter Hurley | da261e7 | 2013-06-15 09:14:14 -0400 | [diff] [blame] | 479 | } else if (!count) |
| 480 | break; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 481 | } |
Jiri Slaby | 2fc2066 | 2012-10-18 22:26:44 +0200 | [diff] [blame] | 482 | clear_bit(TTYP_FLUSHING, &port->iflags); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 483 | } |
Linus Torvalds | 4524200 | 2009-10-14 08:59:49 -0700 | [diff] [blame] | 484 | |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 485 | spin_unlock_irqrestore(&buf->lock, flags); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 486 | |
| 487 | tty_ldisc_deref(disc); |
| 488 | } |
| 489 | |
| 490 | /** |
OGAWA Hirofumi | e043e42 | 2009-07-29 12:15:56 -0700 | [diff] [blame] | 491 | * tty_flush_to_ldisc |
| 492 | * @tty: tty to push |
| 493 | * |
| 494 | * Push the terminal flip buffers to the line discipline. |
| 495 | * |
| 496 | * Must not be called from IRQ context. |
| 497 | */ |
| 498 | void tty_flush_to_ldisc(struct tty_struct *tty) |
| 499 | { |
Jiri Slaby | d6c53c0 | 2013-01-03 15:53:05 +0100 | [diff] [blame] | 500 | if (!tty->port->low_latency) |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 501 | flush_work(&tty->port->buf.work); |
OGAWA Hirofumi | e043e42 | 2009-07-29 12:15:56 -0700 | [diff] [blame] | 502 | } |
| 503 | |
| 504 | /** |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 505 | * tty_flip_buffer_push - terminal |
Jiri Slaby | 2e124b4 | 2013-01-03 15:53:06 +0100 | [diff] [blame] | 506 | * @port: tty port to push |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 507 | * |
| 508 | * Queue a push of the terminal flip buffers to the line discipline. This |
Jiri Slaby | d6c53c0 | 2013-01-03 15:53:05 +0100 | [diff] [blame] | 509 | * function must not be called from IRQ context if port->low_latency is |
| 510 | * set. |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 511 | * |
| 512 | * In the event of the queue being busy for flipping the work will be |
| 513 | * held off and retried later. |
| 514 | * |
| 515 | * Locking: tty buffer lock. Driver locks in low latency mode. |
| 516 | */ |
| 517 | |
Jiri Slaby | 2e124b4 | 2013-01-03 15:53:06 +0100 | [diff] [blame] | 518 | void tty_flip_buffer_push(struct tty_port *port) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 519 | { |
Jiri Slaby | 2e124b4 | 2013-01-03 15:53:06 +0100 | [diff] [blame] | 520 | struct tty_bufhead *buf = &port->buf; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 521 | unsigned long flags; |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 522 | |
| 523 | spin_lock_irqsave(&buf->lock, flags); |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 524 | buf->tail->commit = buf->tail->used; |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 525 | spin_unlock_irqrestore(&buf->lock, flags); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 526 | |
Jiri Slaby | 2e124b4 | 2013-01-03 15:53:06 +0100 | [diff] [blame] | 527 | if (port->low_latency) |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 528 | flush_to_ldisc(&buf->work); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 529 | else |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 530 | schedule_work(&buf->work); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 531 | } |
| 532 | EXPORT_SYMBOL(tty_flip_buffer_push); |
| 533 | |
| 534 | /** |
| 535 | * tty_buffer_init - prepare a tty buffer structure |
| 536 | * @tty: tty to initialise |
| 537 | * |
| 538 | * Set up the initial state of the buffer management for a tty device. |
| 539 | * Must be called before the other tty buffer functions are used. |
| 540 | * |
| 541 | * Locking: none |
| 542 | */ |
| 543 | |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 544 | void tty_buffer_init(struct tty_port *port) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 545 | { |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 546 | struct tty_bufhead *buf = &port->buf; |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 547 | |
| 548 | spin_lock_init(&buf->lock); |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 549 | tty_buffer_reset(&buf->sentinel, 0); |
| 550 | buf->head = &buf->sentinel; |
| 551 | buf->tail = &buf->sentinel; |
Peter Hurley | 809850b | 2013-06-15 09:36:06 -0400 | [diff] [blame] | 552 | init_llist_head(&buf->free); |
Peter Hurley | 7bfe0b7 | 2013-06-15 09:36:08 -0400 | [diff] [blame^] | 553 | atomic_set(&buf->memory_used, 0); |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 554 | INIT_WORK(&buf->work, flush_to_ldisc); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 555 | } |
| 556 | |