xref: /linux/arch/mips/kernel/rtlx.c (revision 858259cf7d1c443c836a2022b78cb281f0a9b95e) 
1 /*
2  * Copyright (C) 2005 MIPS Technologies, Inc.  All rights reserved.
3  *
4  *  This program is free software; you can distribute it and/or modify it
5  *  under the terms of the GNU General Public License (Version 2) as
6  *  published by the Free Software Foundation.
7  *
8  *  This program is distributed in the hope it will be useful, but WITHOUT
9  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
11  *  for more details.
12  *
13  *  You should have received a copy of the GNU General Public License along
14  *  with this program; if not, write to the Free Software Foundation, Inc.,
15  *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
16  *
17  */
18 
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/fs.h>
22 #include <linux/init.h>
23 #include <asm/uaccess.h>
24 #include <linux/slab.h>
25 #include <linux/list.h>
26 #include <linux/vmalloc.h>
27 #include <linux/elf.h>
28 #include <linux/seq_file.h>
29 #include <linux/syscalls.h>
30 #include <linux/moduleloader.h>
31 #include <linux/interrupt.h>
32 #include <linux/poll.h>
33 #include <linux/sched.h>
34 #include <linux/wait.h>
35 #include <asm/mipsmtregs.h>
36 #include <asm/cacheflush.h>
37 #include <asm/atomic.h>
38 #include <asm/cpu.h>
39 #include <asm/processor.h>
40 #include <asm/system.h>
41 #include <asm/rtlx.h>
42 
43 #define RTLX_MAJOR 64
44 #define RTLX_TARG_VPE 1
45 
46 struct rtlx_info *rtlx;
47 static int major;
48 static char module_name[] = "rtlx";
49 static inline int spacefree(int read, int write, int size);
50 
51 static struct chan_waitqueues {
52 	wait_queue_head_t rt_queue;
53 	wait_queue_head_t lx_queue;
54 } channel_wqs[RTLX_CHANNELS];
55 
56 static struct irqaction irq;
57 static int irq_num;
58 
59 extern void *vpe_get_shared(int index);
60 
61 static void rtlx_dispatch(struct pt_regs *regs)
62 {
63 	do_IRQ(MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ, regs);
64 }
65 
66 irqreturn_t rtlx_interrupt(int irq, void *dev_id, struct pt_regs *regs)
67 {
68 	irqreturn_t r = IRQ_HANDLED;
69 	int i;
70 
71 	for (i = 0; i < RTLX_CHANNELS; i++) {
72 		struct rtlx_channel *chan = &rtlx->channel[i];
73 
74 		if (chan->lx_read != chan->lx_write)
75 			wake_up_interruptible(&channel_wqs[i].lx_queue);
76 	}
77 
78 	return r;
79 }
80 
81 void dump_rtlx(void)
82 {
83 	int i;
84 
85 	printk("id 0x%lx state %d\n", rtlx->id, rtlx->state);
86 
87 	for (i = 0; i < RTLX_CHANNELS; i++) {
88 		struct rtlx_channel *chan = &rtlx->channel[i];
89 
90 		printk(" rt_state %d lx_state %d buffer_size %d\n",
91 		       chan->rt_state, chan->lx_state, chan->buffer_size);
92 
93 		printk(" rt_read %d rt_write %d\n",
94 		       chan->rt_read, chan->rt_write);
95 
96 		printk(" lx_read %d lx_write %d\n",
97 		       chan->lx_read, chan->lx_write);
98 
99 		printk(" rt_buffer <%s>\n", chan->rt_buffer);
100 		printk(" lx_buffer <%s>\n", chan->lx_buffer);
101 	}
102 }
103 
104 /* call when we have the address of the shared structure from the SP side. */
105 static int rtlx_init(struct rtlx_info *rtlxi)
106 {
107 	int i;
108 
109 	if (rtlxi->id != RTLX_ID) {
110 		printk(KERN_WARNING "no valid RTLX id at 0x%p\n", rtlxi);
111 		return (-ENOEXEC);
112 	}
113 
114 	/* initialise the wait queues */
115 	for (i = 0; i < RTLX_CHANNELS; i++) {
116 		init_waitqueue_head(&channel_wqs[i].rt_queue);
117 		init_waitqueue_head(&channel_wqs[i].lx_queue);
118 	}
119 
120 	/* set up for interrupt handling */
121 	memset(&irq, 0, sizeof(struct irqaction));
122 
123 	if (cpu_has_vint) {
124 		set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
125 	}
126 
127 	irq_num = MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ;
128 	irq.handler = rtlx_interrupt;
129 	irq.flags = SA_INTERRUPT;
130 	irq.name = "RTLX";
131 	irq.dev_id = rtlx;
132 	setup_irq(irq_num, &irq);
133 
134 	rtlx = rtlxi;
135 	return (0);
136 }
137 
138 /* only allow one open process at a time to open each channel */
139 static int rtlx_open(struct inode *inode, struct file *filp)
140 {
141 	int minor, ret;
142 	struct rtlx_channel *chan;
143 
144 	/* assume only 1 device at the mo. */
145 	minor = MINOR(inode->i_rdev);
146 
147 	if (rtlx == NULL) {
148 		struct rtlx_info **p;
149 		if( (p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
150 			printk(" vpe_get_shared is NULL. Has an SP program been loaded?\n");
151 			return (-EFAULT);
152 		}
153 
154 		if (*p == NULL) {
155 			printk(" vpe_shared %p %p\n", p, *p);
156 			return (-EFAULT);
157 		}
158 
159 		if ((ret = rtlx_init(*p)) < 0)
160 			return (ret);
161 	}
162 
163 	chan = &rtlx->channel[minor];
164 
165 	/* already open? */
166 	if (chan->lx_state == RTLX_STATE_OPENED)
167 		return (-EBUSY);
168 
169 	chan->lx_state = RTLX_STATE_OPENED;
170 	return (0);
171 }
172 
173 static int rtlx_release(struct inode *inode, struct file *filp)
174 {
175 	int minor;
176 
177 	minor = MINOR(inode->i_rdev);
178 	rtlx->channel[minor].lx_state = RTLX_STATE_UNUSED;
179 	return (0);
180 }
181 
182 static unsigned int rtlx_poll(struct file *file, poll_table * wait)
183 {
184 	int minor;
185 	unsigned int mask = 0;
186 	struct rtlx_channel *chan;
187 
188 	minor = MINOR(file->f_dentry->d_inode->i_rdev);
189 	chan = &rtlx->channel[minor];
190 
191 	poll_wait(file, &channel_wqs[minor].rt_queue, wait);
192 	poll_wait(file, &channel_wqs[minor].lx_queue, wait);
193 
194 	/* data available to read? */
195 	if (chan->lx_read != chan->lx_write)
196 		mask |= POLLIN | POLLRDNORM;
197 
198 	/* space to write */
199 	if (spacefree(chan->rt_read, chan->rt_write, chan->buffer_size))
200 		mask |= POLLOUT | POLLWRNORM;
201 
202 	return (mask);
203 }
204 
205 static ssize_t rtlx_read(struct file *file, char __user * buffer, size_t count,
206 			 loff_t * ppos)
207 {
208 	size_t fl = 0L;
209 	int minor;
210 	struct rtlx_channel *lx;
211 	DECLARE_WAITQUEUE(wait, current);
212 
213 	minor = MINOR(file->f_dentry->d_inode->i_rdev);
214 	lx = &rtlx->channel[minor];
215 
216 	/* data available? */
217 	if (lx->lx_write == lx->lx_read) {
218 		if (file->f_flags & O_NONBLOCK)
219 			return (0);	// -EAGAIN makes cat whinge
220 
221 		/* go to sleep */
222 		add_wait_queue(&channel_wqs[minor].lx_queue, &wait);
223 		set_current_state(TASK_INTERRUPTIBLE);
224 
225 		while (lx->lx_write == lx->lx_read)
226 			schedule();
227 
228 		set_current_state(TASK_RUNNING);
229 		remove_wait_queue(&channel_wqs[minor].lx_queue, &wait);
230 
231 		/* back running */
232 	}
233 
234 	/* find out how much in total */
235 	count = min( count,
236 		     (size_t)(lx->lx_write + lx->buffer_size - lx->lx_read) % lx->buffer_size);
237 
238 	/* then how much from the read pointer onwards */
239 	fl = min( count, (size_t)lx->buffer_size - lx->lx_read);
240 
241 	copy_to_user (buffer, &lx->lx_buffer[lx->lx_read], fl);
242 
243 	/* and if there is anything left at the beginning of the buffer */
244 	if ( count - fl )
245 		copy_to_user (buffer + fl, lx->lx_buffer, count - fl);
246 
247 	/* update the index */
248 	lx->lx_read += count;
249 	lx->lx_read %= lx->buffer_size;
250 
251 	return (count);
252 }
253 
254 static inline int spacefree(int read, int write, int size)
255 {
256 	if (read == write) {
257 		/* never fill the buffer completely, so indexes are always equal if empty
258 		   and only empty, or !equal if data available */
259 		return (size - 1);
260 	}
261 
262 	return ((read + size - write) % size) - 1;
263 }
264 
265 static ssize_t rtlx_write(struct file *file, const char __user * buffer,
266 			  size_t count, loff_t * ppos)
267 {
268 	int minor;
269 	struct rtlx_channel *rt;
270 	size_t fl;
271 	DECLARE_WAITQUEUE(wait, current);
272 
273 	minor = MINOR(file->f_dentry->d_inode->i_rdev);
274 	rt = &rtlx->channel[minor];
275 
276 	/* any space left... */
277 	if (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size)) {
278 
279 		if (file->f_flags & O_NONBLOCK)
280 			return (-EAGAIN);
281 
282 		add_wait_queue(&channel_wqs[minor].rt_queue, &wait);
283 		set_current_state(TASK_INTERRUPTIBLE);
284 
285 		while (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size))
286 			schedule();
287 
288 		set_current_state(TASK_RUNNING);
289 		remove_wait_queue(&channel_wqs[minor].rt_queue, &wait);
290 	}
291 
292 	/* total number of bytes to copy */
293 	count = min( count, (size_t)spacefree(rt->rt_read, rt->rt_write, rt->buffer_size) );
294 
295 	/* first bit from write pointer to the end of the buffer, or count */
296 	fl = min(count, (size_t) rt->buffer_size - rt->rt_write);
297 
298 	copy_from_user(&rt->rt_buffer[rt->rt_write], buffer, fl);
299 
300 	/* if there's any left copy to the beginning of the buffer */
301 	if( count - fl )
302 		copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
303 
304 	rt->rt_write += count;
305 	rt->rt_write %= rt->buffer_size;
306 
307 	return(count);
308 }
309 
310 static struct file_operations rtlx_fops = {
311 	.owner = THIS_MODULE,
312 	.open = rtlx_open,
313 	.release = rtlx_release,
314 	.write = rtlx_write,
315 	.read = rtlx_read,
316 	.poll = rtlx_poll
317 };
318 
319 static int rtlx_module_init(void)
320 {
321 	if ((major = register_chrdev(RTLX_MAJOR, module_name, &rtlx_fops)) < 0) {
322 		printk("rtlx_module_init: unable to register device\n");
323 		return (-EBUSY);
324 	}
325 
326 	if (major == 0)
327 		major = RTLX_MAJOR;
328 
329 	return (0);
330 }
331 
332 static void rtlx_module_exit(void)
333 {
334 	unregister_chrdev(major, module_name);
335 }
336 
337 module_init(rtlx_module_init);
338 module_exit(rtlx_module_exit);
339 MODULE_DESCRIPTION("MIPS RTLX");
340 MODULE_AUTHOR("Elizabeth Clarke, MIPS Technologies, Inc");
341 MODULE_LICENSE("GPL");
342