Peter M. Groen / tty0tty

Commit ba738340352a108768f7ff2b81251093d0432205

Authored by Craig McQueen
1 parent 90a8691f

Simplify references to paired serial port.

Inline Side-by-side
Showing 1 changed file with 24 additions and 48 deletions
module/tty0tty.c
  View file @ba73834
... ... @@ -52,6 +52,12 @@ MODULE_LICENSE("GPL");
52 52 #define TINY_TTY_MAJOR 240 /* experimental range */
53 53 #define TINY_TTY_MINORS 8 /* device number, always even*/
54 54  
  55 +/* Serial ports are paired by adjacent index numbers -- 0 and 1, 2 and 3, 4 and 5.
  56 + * I.e. same upper bits of index number; only different least-significant-bit.
  57 + * XOR least-significant-bit to find index of paired serial port.
  58 + */
  59 +#define PAIRED_INDEX(INDEX) ((INDEX) ^ 1)
  60 +
55 61 /* fake UART values */
56 62 //out
57 63 #define MCR_DTR 0x01
... ... @@ -85,6 +91,7 @@ static int tty0tty_open(struct tty_struct *tty, struct file *file)
85 91 {
86 92 struct tty0tty_serial *tty0tty;
87 93 int index;
  94 + int paired_index;
88 95 int msr=0;
89 96 int mcr=0;
90 97  
... ... @@ -96,6 +103,7 @@ static int tty0tty_open(struct tty_struct *tty, struct file *file)
96 103  
97 104 /* get the serial object associated with this tty pointer */
98 105 index = tty->index;
  106 + paired_index = PAIRED_INDEX(index);
99 107 tty0tty = tty0tty_table[index];
100 108 if (tty0tty == NULL) {
101 109 /* first time accessing this device, let's create it */
... ... @@ -114,18 +122,9 @@ static int tty0tty_open(struct tty_struct *tty, struct file *file)
114 122  
115 123 }
116 124  
117   - if( (index % 2) == 0)
118   - {
119   - if(tty0tty_table[index+1] != NULL)
120   - if (tty0tty_table[index+1]->open_count > 0)
121   - mcr=tty0tty_table[index+1]->mcr;
122   - }
123   - else
124   - {
125   - if(tty0tty_table[index-1] != NULL)
126   - if (tty0tty_table[index-1]->open_count > 0)
127   - mcr=tty0tty_table[index-1]->mcr;
128   - }
  125 + if (tty0tty_table[paired_index] != NULL &&
  126 + tty0tty_table[paired_index]->open_count > 0)
  127 + mcr = tty0tty_table[paired_index]->mcr;
129 128  
130 129 //null modem connection
131 130  
... ... @@ -188,6 +187,7 @@ static int tty0tty_write(struct tty_struct *tty, const unsigned char *buffer, in
188 187 struct tty0tty_serial *tty0tty = tty->driver_data;
189 188 int retval = -EINVAL;
190 189 struct tty_struct *ttyx = NULL;
  190 + int paired_index;
191 191  
192 192 if (!tty0tty)
193 193 return -ENODEV;
... ... @@ -198,18 +198,10 @@ static int tty0tty_write(struct tty_struct *tty, const unsigned char *buffer, in
198 198 /* port was not opened */
199 199 goto exit;
200 200  
201   - if( (tty0tty->tty->index % 2) == 0)
202   - {
203   - if(tty0tty_table[tty0tty->tty->index+1] != NULL)
204   - if (tty0tty_table[tty0tty->tty->index+1]->open_count > 0)
205   - ttyx=tty0tty_table[tty0tty->tty->index+1]->tty;
206   - }
207   - else
208   - {
209   - if(tty0tty_table[tty0tty->tty->index-1] != NULL)
210   - if (tty0tty_table[tty0tty->tty->index-1]->open_count > 0)
211   - ttyx=tty0tty_table[tty0tty->tty->index-1]->tty;
212   - }
  201 + paired_index = PAIRED_INDEX(tty0tty->tty->index);
  202 + if (tty0tty_table[paired_index] != NULL &&
  203 + tty0tty_table[paired_index]->open_count > 0)
  204 + ttyx = tty0tty_table[paired_index]->tty;
213 205  
214 206 // tty->low_latency=1;
215 207  
... ... @@ -364,23 +356,16 @@ static int tty0tty_tiocmset(struct tty_struct *tty, struct file *file,
364 356 struct tty0tty_serial *tty0tty = tty->driver_data;
365 357 unsigned int mcr = tty0tty->mcr;
366 358 unsigned int msr=0;
  359 + int paired_index;
367 360  
368 361 #ifdef SCULL_DEBUG
369 362 printk(KERN_DEBUG "%s - \n", __FUNCTION__);
370 363 #endif
371 364  
372   - if( (tty0tty->tty->index % 2) == 0)
373   - {
374   - if(tty0tty_table[tty0tty->tty->index+1] != NULL)
375   - if (tty0tty_table[tty0tty->tty->index+1]->open_count > 0)
376   - msr=tty0tty_table[tty0tty->tty->index+1]->msr;
377   - }
378   - else
379   - {
380   - if(tty0tty_table[tty0tty->tty->index-1] != NULL)
381   - if (tty0tty_table[tty0tty->tty->index-1]->open_count > 0)
382   - msr=tty0tty_table[tty0tty->tty->index-1]->msr;
383   - }
  365 + paired_index = PAIRED_INDEX(tty0tty->tty->index);
  366 + if (tty0tty_table[paired_index] != NULL &&
  367 + tty0tty_table[paired_index]->open_count > 0)
  368 + msr = tty0tty_table[paired_index]->msr;
384 369  
385 370 //null modem connection
386 371  
... ... @@ -414,18 +399,9 @@ static int tty0tty_tiocmset(struct tty_struct *tty, struct file *file,
414 399 /* set the new MCR value in the device */
415 400 tty0tty->mcr = mcr;
416 401  
417   - if( (tty0tty->tty->index % 2) == 0)
418   - {
419   - if(tty0tty_table[tty0tty->tty->index+1] != NULL)
420   - if (tty0tty_table[tty0tty->tty->index+1]->open_count > 0)
421   - tty0tty_table[tty0tty->tty->index+1]->msr=msr;
422   - }
423   - else
424   - {
425   - if(tty0tty_table[tty0tty->tty->index-1] != NULL)
426   - if (tty0tty_table[tty0tty->tty->index-1]->open_count > 0)
427   - tty0tty_table[tty0tty->tty->index-1]->msr=msr;
428   - }
  402 + if (tty0tty_table[paired_index] != NULL &&
  403 + tty0tty_table[paired_index]->open_count > 0)
  404 + tty0tty_table[paired_index]->msr = msr;
429 405 return 0;
430 406 }
431 407  
... ...