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 <linux/poll.h> 24 #include <linux/sched.h> 25 #include <linux/wait.h> 26 #include <asm/mipsmtregs.h> 27 #include <asm/bitops.h> 28 #include <asm/cpu.h> 29 #include <asm/processor.h> 30 #include <asm/rtlx.h> 31 #include <asm/uaccess.h> 32 33 #define RTLX_TARG_VPE 1 34 35 static struct rtlx_info *rtlx; 36 static int major; 37 static char module_name[] = "rtlx"; 38 static struct irqaction irq; 39 static int irq_num; 40 41 static inline int spacefree(int read, int write, int size) 42 { 43 if (read == write) { 44 /* 45 * never fill the buffer completely, so indexes are always 46 * equal if empty and only empty, or !equal if data available 47 */ 48 return size - 1; 49 } 50 51 return ((read + size - write) % size) - 1; 52 } 53 54 static struct chan_waitqueues { 55 wait_queue_head_t rt_queue; 56 wait_queue_head_t lx_queue; 57 } channel_wqs[RTLX_CHANNELS]; 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 static irqreturn_t rtlx_interrupt(int irq, void *dev_id, struct pt_regs *regs) 67 { 68 int i; 69 70 for (i = 0; i < RTLX_CHANNELS; i++) { 71 struct rtlx_channel *chan = &rtlx->channel[i]; 72 73 if (chan->lx_read != chan->lx_write) 74 wake_up_interruptible(&channel_wqs[i].lx_queue); 75 } 76 77 return IRQ_HANDLED; 78 } 79 80 /* call when we have the address of the shared structure from the SP side. */ 81 static int rtlx_init(struct rtlx_info *rtlxi) 82 { 83 int i; 84 85 if (rtlxi->id != RTLX_ID) { 86 printk(KERN_WARNING "no valid RTLX id at 0x%p\n", rtlxi); 87 return -ENOEXEC; 88 } 89 90 /* initialise the wait queues */ 91 for (i = 0; i < RTLX_CHANNELS; i++) { 92 init_waitqueue_head(&channel_wqs[i].rt_queue); 93 init_waitqueue_head(&channel_wqs[i].lx_queue); 94 } 95 96 /* set up for interrupt handling */ 97 memset(&irq, 0, sizeof(struct irqaction)); 98 99 if (cpu_has_vint) 100 set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch); 101 102 irq_num = MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ; 103 irq.handler = rtlx_interrupt; 104 irq.flags = SA_INTERRUPT; 105 irq.name = "RTLX"; 106 irq.dev_id = rtlx; 107 setup_irq(irq_num, &irq); 108 109 rtlx = rtlxi; 110 111 return 0; 112 } 113 114 /* only allow one open process at a time to open each channel */ 115 static int rtlx_open(struct inode *inode, struct file *filp) 116 { 117 int minor, ret; 118 struct rtlx_channel *chan; 119 120 /* assume only 1 device at the mo. */ 121 minor = MINOR(inode->i_rdev); 122 123 if (rtlx == NULL) { 124 struct rtlx_info **p; 125 if( (p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) { 126 printk(KERN_ERR "vpe_get_shared is NULL. " 127 "Has an SP program been loaded?\n"); 128 return -EFAULT; 129 } 130 131 if (*p == NULL) { 132 printk(KERN_ERR "vpe_shared %p %p\n", p, *p); 133 return -EFAULT; 134 } 135 136 if ((ret = rtlx_init(*p)) < 0) 137 return ret; 138 } 139 140 chan = &rtlx->channel[minor]; 141 142 if (test_and_set_bit(RTLX_STATE_OPENED, &chan->lx_state)) 143 return -EBUSY; 144 145 return 0; 146 } 147 148 static int rtlx_release(struct inode *inode, struct file *filp) 149 { 150 int minor = MINOR(inode->i_rdev); 151 152 clear_bit(RTLX_STATE_OPENED, &rtlx->channel[minor].lx_state); 153 smp_mb__after_clear_bit(); 154 155 return 0; 156 } 157 158 static unsigned int rtlx_poll(struct file *file, poll_table * wait) 159 { 160 int minor; 161 unsigned int mask = 0; 162 struct rtlx_channel *chan; 163 164 minor = MINOR(file->f_dentry->d_inode->i_rdev); 165 chan = &rtlx->channel[minor]; 166 167 poll_wait(file, &channel_wqs[minor].rt_queue, wait); 168 poll_wait(file, &channel_wqs[minor].lx_queue, wait); 169 170 /* data available to read? */ 171 if (chan->lx_read != chan->lx_write) 172 mask |= POLLIN | POLLRDNORM; 173 174 /* space to write */ 175 if (spacefree(chan->rt_read, chan->rt_write, chan->buffer_size)) 176 mask |= POLLOUT | POLLWRNORM; 177 178 return mask; 179 } 180 181 static ssize_t rtlx_read(struct file *file, char __user * buffer, size_t count, 182 loff_t * ppos) 183 { 184 unsigned long failed; 185 size_t fl = 0L; 186 int minor; 187 struct rtlx_channel *lx; 188 DECLARE_WAITQUEUE(wait, current); 189 190 minor = MINOR(file->f_dentry->d_inode->i_rdev); 191 lx = &rtlx->channel[minor]; 192 193 /* data available? */ 194 if (lx->lx_write == lx->lx_read) { 195 if (file->f_flags & O_NONBLOCK) 196 return 0; /* -EAGAIN makes cat whinge */ 197 198 /* go to sleep */ 199 add_wait_queue(&channel_wqs[minor].lx_queue, &wait); 200 set_current_state(TASK_INTERRUPTIBLE); 201 202 while (lx->lx_write == lx->lx_read) 203 schedule(); 204 205 set_current_state(TASK_RUNNING); 206 remove_wait_queue(&channel_wqs[minor].lx_queue, &wait); 207 208 /* back running */ 209 } 210 211 /* find out how much in total */ 212 count = min(count, 213 (size_t)(lx->lx_write + lx->buffer_size - lx->lx_read) % lx->buffer_size); 214 215 /* then how much from the read pointer onwards */ 216 fl = min(count, (size_t)lx->buffer_size - lx->lx_read); 217 218 failed = copy_to_user (buffer, &lx->lx_buffer[lx->lx_read], fl); 219 if (failed) { 220 count = fl - failed; 221 goto out; 222 } 223 224 /* and if there is anything left at the beginning of the buffer */ 225 if (count - fl) { 226 failed = copy_to_user (buffer + fl, lx->lx_buffer, count - fl); 227 if (failed) { 228 count -= failed; 229 goto out; 230 } 231 } 232 233 out: 234 /* update the index */ 235 lx->lx_read += count; 236 lx->lx_read %= lx->buffer_size; 237 238 return count; 239 } 240 241 static ssize_t rtlx_write(struct file *file, const char __user * buffer, 242 size_t count, loff_t * ppos) 243 { 244 unsigned long failed; 245 int minor; 246 struct rtlx_channel *rt; 247 size_t fl; 248 DECLARE_WAITQUEUE(wait, current); 249 250 minor = MINOR(file->f_dentry->d_inode->i_rdev); 251 rt = &rtlx->channel[minor]; 252 253 /* any space left... */ 254 if (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size)) { 255 256 if (file->f_flags & O_NONBLOCK) 257 return -EAGAIN; 258 259 add_wait_queue(&channel_wqs[minor].rt_queue, &wait); 260 set_current_state(TASK_INTERRUPTIBLE); 261 262 while (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size)) 263 schedule(); 264 265 set_current_state(TASK_RUNNING); 266 remove_wait_queue(&channel_wqs[minor].rt_queue, &wait); 267 } 268 269 /* total number of bytes to copy */ 270 count = min(count, (size_t)spacefree(rt->rt_read, rt->rt_write, rt->buffer_size) ); 271 272 /* first bit from write pointer to the end of the buffer, or count */ 273 fl = min(count, (size_t) rt->buffer_size - rt->rt_write); 274 275 failed = copy_from_user(&rt->rt_buffer[rt->rt_write], buffer, fl); 276 if (failed) { 277 count = fl - failed; 278 goto out; 279 } 280 281 /* if there's any left copy to the beginning of the buffer */ 282 if (count - fl) { 283 failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl); 284 if (failed) { 285 count -= failed; 286 goto out; 287 } 288 } 289 290 out: 291 rt->rt_write += count; 292 rt->rt_write %= rt->buffer_size; 293 294 return count; 295 } 296 297 static struct file_operations rtlx_fops = { 298 .owner = THIS_MODULE, 299 .open = rtlx_open, 300 .release = rtlx_release, 301 .write = rtlx_write, 302 .read = rtlx_read, 303 .poll = rtlx_poll 304 }; 305 306 static char register_chrdev_failed[] __initdata = 307 KERN_ERR "rtlx_module_init: unable to register device\n"; 308 309 static int __init rtlx_module_init(void) 310 { 311 major = register_chrdev(0, module_name, &rtlx_fops); 312 if (major < 0) { 313 printk(register_chrdev_failed); 314 return major; 315 } 316 317 return 0; 318 } 319 320 static void __exit rtlx_module_exit(void) 321 { 322 unregister_chrdev(major, module_name); 323 } 324 325 module_init(rtlx_module_init); 326 module_exit(rtlx_module_exit); 327 328 MODULE_DESCRIPTION("MIPS RTLX"); 329 MODULE_AUTHOR("Elizabeth Clarke, MIPS Technologies, Inc."); 330 MODULE_LICENSE("GPL"); 331