mm: remove gup_flags FOLL_WRITE games from __get_user_pages()
[deliverable/linux.git] / drivers / tty / bfin_jtag_comm.c
CommitLineData
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1/*
2 * TTY over Blackfin JTAG Communication
3 *
4 * Copyright 2008-2009 Analog Devices Inc.
5 *
6 * Enter bugs at http://blackfin.uclinux.org/
7 *
8 * Licensed under the GPL-2 or later.
9 */
10
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11#define DRV_NAME "bfin-jtag-comm"
12#define DEV_NAME "ttyBFJC"
13#define pr_fmt(fmt) DRV_NAME ": " fmt
14
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15#include <linux/circ_buf.h>
16#include <linux/console.h>
17#include <linux/delay.h>
18#include <linux/err.h>
19#include <linux/kernel.h>
20#include <linux/kthread.h>
21#include <linux/module.h>
22#include <linux/mutex.h>
23#include <linux/sched.h>
5a0e3ad6 24#include <linux/slab.h>
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25#include <linux/tty.h>
26#include <linux/tty_driver.h>
27#include <linux/tty_flip.h>
60063497 28#include <linux/atomic.h>
0b914218 29
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30#define pr_init(fmt, args...) ({ static const __initconst char __fmt[] = fmt; printk(__fmt, ## args); })
31
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32/* See the Debug/Emulation chapter in the HRM */
33#define EMUDOF 0x00000001 /* EMUDAT_OUT full & valid */
34#define EMUDIF 0x00000002 /* EMUDAT_IN full & valid */
35#define EMUDOOVF 0x00000004 /* EMUDAT_OUT overflow */
36#define EMUDIOVF 0x00000008 /* EMUDAT_IN overflow */
37
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38static inline uint32_t bfin_write_emudat(uint32_t emudat)
39{
40 __asm__ __volatile__("emudat = %0;" : : "d"(emudat));
41 return emudat;
42}
43
44static inline uint32_t bfin_read_emudat(void)
45{
46 uint32_t emudat;
47 __asm__ __volatile__("%0 = emudat;" : "=d"(emudat));
48 return emudat;
49}
50
51static inline uint32_t bfin_write_emudat_chars(char a, char b, char c, char d)
52{
53 return bfin_write_emudat((a << 0) | (b << 8) | (c << 16) | (d << 24));
54}
55
56#define CIRC_SIZE 2048 /* see comment in tty_io.c:do_tty_write() */
57#define CIRC_MASK (CIRC_SIZE - 1)
58#define circ_empty(circ) ((circ)->head == (circ)->tail)
59#define circ_free(circ) CIRC_SPACE((circ)->head, (circ)->tail, CIRC_SIZE)
60#define circ_cnt(circ) CIRC_CNT((circ)->head, (circ)->tail, CIRC_SIZE)
61#define circ_byte(circ, idx) ((circ)->buf[(idx) & CIRC_MASK])
62
63static struct tty_driver *bfin_jc_driver;
64static struct task_struct *bfin_jc_kthread;
560460b8 65static struct tty_port port;
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66static volatile struct circ_buf bfin_jc_write_buf;
67
68static int
69bfin_jc_emudat_manager(void *arg)
70{
71 uint32_t inbound_len = 0, outbound_len = 0;
72
73 while (!kthread_should_stop()) {
e63f9f74 74 struct tty_struct *tty = tty_port_tty_get(&port);
0b914218 75 /* no one left to give data to, so sleep */
e63f9f74 76 if (tty == NULL && circ_empty(&bfin_jc_write_buf)) {
56578abf 77 pr_debug("waiting for readers\n");
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78 __set_current_state(TASK_UNINTERRUPTIBLE);
79 schedule();
e63f9f74 80 continue;
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81 }
82
83 /* no data available, so just chill */
84 if (!(bfin_read_DBGSTAT() & EMUDIF) && circ_empty(&bfin_jc_write_buf)) {
56578abf 85 pr_debug("waiting for data (in_len = %i) (circ: %i %i)\n",
0b914218 86 inbound_len, bfin_jc_write_buf.tail, bfin_jc_write_buf.head);
e63f9f74 87 tty_kref_put(tty);
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88 if (inbound_len)
89 schedule();
90 else
91 schedule_timeout_interruptible(HZ);
92 continue;
93 }
94
95 /* if incoming data is ready, eat it */
96 if (bfin_read_DBGSTAT() & EMUDIF) {
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97 uint32_t emudat = bfin_read_emudat();
98 if (inbound_len == 0) {
99 pr_debug("incoming length: 0x%08x\n", emudat);
100 inbound_len = emudat;
101 } else {
102 size_t num_chars = (4 <= inbound_len ? 4 : inbound_len);
103 pr_debug(" incoming data: 0x%08x (pushing %zu)\n", emudat, num_chars);
104 inbound_len -= num_chars;
105 tty_insert_flip_string(&port, (unsigned char *)&emudat, num_chars);
106 tty_flip_buffer_push(&port);
0b914218 107 }
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108 }
109
110 /* if outgoing data is ready, post it */
111 if (!(bfin_read_DBGSTAT() & EMUDOF) && !circ_empty(&bfin_jc_write_buf)) {
112 if (outbound_len == 0) {
113 outbound_len = circ_cnt(&bfin_jc_write_buf);
114 bfin_write_emudat(outbound_len);
56578abf 115 pr_debug("outgoing length: 0x%08x\n", outbound_len);
0b914218 116 } else {
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117 int tail = bfin_jc_write_buf.tail;
118 size_t ate = (4 <= outbound_len ? 4 : outbound_len);
119 uint32_t emudat =
120 bfin_write_emudat_chars(
121 circ_byte(&bfin_jc_write_buf, tail + 0),
122 circ_byte(&bfin_jc_write_buf, tail + 1),
123 circ_byte(&bfin_jc_write_buf, tail + 2),
124 circ_byte(&bfin_jc_write_buf, tail + 3)
125 );
126 bfin_jc_write_buf.tail += ate;
127 outbound_len -= ate;
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128 if (tty)
129 tty_wakeup(tty);
56578abf 130 pr_debug(" outgoing data: 0x%08x (pushing %zu)\n", emudat, ate);
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131 }
132 }
e63f9f74 133 tty_kref_put(tty);
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134 }
135
136 __set_current_state(TASK_RUNNING);
137 return 0;
138}
139
140static int
141bfin_jc_open(struct tty_struct *tty, struct file *filp)
142{
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143 unsigned long flags;
144
145 spin_lock_irqsave(&port.lock, flags);
560460b8 146 port.count++;
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147 spin_unlock_irqrestore(&port.lock, flags);
148 tty_port_tty_set(&port, tty);
0b914218 149 wake_up_process(bfin_jc_kthread);
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150 return 0;
151}
152
153static void
154bfin_jc_close(struct tty_struct *tty, struct file *filp)
155{
e63f9f74
JS
156 unsigned long flags;
157 bool last;
158
159 spin_lock_irqsave(&port.lock, flags);
160 last = --port.count == 0;
161 spin_unlock_irqrestore(&port.lock, flags);
162 if (last)
163 tty_port_tty_set(&port, NULL);
0b914218 164 wake_up_process(bfin_jc_kthread);
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165}
166
167/* XXX: we dont handle the put_char() case where we must handle count = 1 */
168static int
169bfin_jc_circ_write(const unsigned char *buf, int count)
170{
171 int i;
172 count = min(count, circ_free(&bfin_jc_write_buf));
56578abf 173 pr_debug("going to write chunk of %i bytes\n", count);
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174 for (i = 0; i < count; ++i)
175 circ_byte(&bfin_jc_write_buf, bfin_jc_write_buf.head + i) = buf[i];
176 bfin_jc_write_buf.head += i;
177 return i;
178}
179
180#ifndef CONFIG_BFIN_JTAG_COMM_CONSOLE
ac751efa
TH
181# define console_lock()
182# define console_unlock()
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183#endif
184static int
185bfin_jc_write(struct tty_struct *tty, const unsigned char *buf, int count)
186{
187 int i;
ac751efa 188 console_lock();
0b914218 189 i = bfin_jc_circ_write(buf, count);
ac751efa 190 console_unlock();
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MF
191 wake_up_process(bfin_jc_kthread);
192 return i;
193}
194
195static void
196bfin_jc_flush_chars(struct tty_struct *tty)
197{
198 wake_up_process(bfin_jc_kthread);
199}
200
201static int
202bfin_jc_write_room(struct tty_struct *tty)
203{
204 return circ_free(&bfin_jc_write_buf);
205}
206
207static int
208bfin_jc_chars_in_buffer(struct tty_struct *tty)
209{
210 return circ_cnt(&bfin_jc_write_buf);
211}
212
1cceefd3 213static const struct tty_operations bfin_jc_ops = {
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214 .open = bfin_jc_open,
215 .close = bfin_jc_close,
216 .write = bfin_jc_write,
217 /*.put_char = bfin_jc_put_char,*/
218 .flush_chars = bfin_jc_flush_chars,
219 .write_room = bfin_jc_write_room,
220 .chars_in_buffer = bfin_jc_chars_in_buffer,
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221};
222
223static int __init bfin_jc_init(void)
224{
225 int ret;
226
227 bfin_jc_kthread = kthread_create(bfin_jc_emudat_manager, NULL, DRV_NAME);
228 if (IS_ERR(bfin_jc_kthread))
229 return PTR_ERR(bfin_jc_kthread);
230
231 ret = -ENOMEM;
232
233 bfin_jc_write_buf.head = bfin_jc_write_buf.tail = 0;
234 bfin_jc_write_buf.buf = kmalloc(CIRC_SIZE, GFP_KERNEL);
235 if (!bfin_jc_write_buf.buf)
d9d691f5 236 goto err_buf;
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237
238 bfin_jc_driver = alloc_tty_driver(1);
239 if (!bfin_jc_driver)
d9d691f5 240 goto err_driver;
0b914218 241
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242 tty_port_init(&port);
243
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MF
244 bfin_jc_driver->driver_name = DRV_NAME;
245 bfin_jc_driver->name = DEV_NAME;
246 bfin_jc_driver->type = TTY_DRIVER_TYPE_SERIAL;
247 bfin_jc_driver->subtype = SERIAL_TYPE_NORMAL;
248 bfin_jc_driver->init_termios = tty_std_termios;
249 tty_set_operations(bfin_jc_driver, &bfin_jc_ops);
b19e2ca7 250 tty_port_link_device(&port, bfin_jc_driver, 0);
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251
252 ret = tty_register_driver(bfin_jc_driver);
253 if (ret)
254 goto err;
255
256 pr_init(KERN_INFO DRV_NAME ": initialized\n");
257
258 return 0;
259
260 err:
191c5f10 261 tty_port_destroy(&port);
0b914218 262 put_tty_driver(bfin_jc_driver);
d9d691f5 263 err_driver:
0b914218 264 kfree(bfin_jc_write_buf.buf);
d9d691f5 265 err_buf:
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MF
266 kthread_stop(bfin_jc_kthread);
267 return ret;
268}
269module_init(bfin_jc_init);
270
271static void __exit bfin_jc_exit(void)
272{
273 kthread_stop(bfin_jc_kthread);
274 kfree(bfin_jc_write_buf.buf);
275 tty_unregister_driver(bfin_jc_driver);
276 put_tty_driver(bfin_jc_driver);
191c5f10 277 tty_port_destroy(&port);
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MF
278}
279module_exit(bfin_jc_exit);
280
281#if defined(CONFIG_BFIN_JTAG_COMM_CONSOLE) || defined(CONFIG_EARLY_PRINTK)
282static void
283bfin_jc_straight_buffer_write(const char *buf, unsigned count)
284{
285 unsigned ate = 0;
286 while (bfin_read_DBGSTAT() & EMUDOF)
287 continue;
288 bfin_write_emudat(count);
289 while (ate < count) {
290 while (bfin_read_DBGSTAT() & EMUDOF)
291 continue;
292 bfin_write_emudat_chars(buf[ate], buf[ate+1], buf[ate+2], buf[ate+3]);
293 ate += 4;
294 }
295}
296#endif
297
298#ifdef CONFIG_BFIN_JTAG_COMM_CONSOLE
299static void
300bfin_jc_console_write(struct console *co, const char *buf, unsigned count)
301{
302 if (bfin_jc_kthread == NULL)
303 bfin_jc_straight_buffer_write(buf, count);
304 else
305 bfin_jc_circ_write(buf, count);
306}
307
308static struct tty_driver *
309bfin_jc_console_device(struct console *co, int *index)
310{
311 *index = co->index;
312 return bfin_jc_driver;
313}
314
315static struct console bfin_jc_console = {
316 .name = DEV_NAME,
317 .write = bfin_jc_console_write,
318 .device = bfin_jc_console_device,
319 .flags = CON_ANYTIME | CON_PRINTBUFFER,
320 .index = -1,
321};
322
323static int __init bfin_jc_console_init(void)
324{
325 register_console(&bfin_jc_console);
326 return 0;
327}
328console_initcall(bfin_jc_console_init);
329#endif
330
331#ifdef CONFIG_EARLY_PRINTK
332static void __init
333bfin_jc_early_write(struct console *co, const char *buf, unsigned int count)
334{
335 bfin_jc_straight_buffer_write(buf, count);
336}
337
f8294523 338static struct console bfin_jc_early_console __initdata = {
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MF
339 .name = "early_BFJC",
340 .write = bfin_jc_early_write,
341 .flags = CON_ANYTIME | CON_PRINTBUFFER,
342 .index = -1,
343};
344
345struct console * __init
346bfin_jc_early_init(unsigned int port, unsigned int cflag)
347{
348 return &bfin_jc_early_console;
349}
350#endif
351
352MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>");
353MODULE_DESCRIPTION("TTY over Blackfin JTAG Communication");
354MODULE_LICENSE("GPL");
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