Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  1 /*
  2  * drivers/sbus/char/bpp.c
  3  *
  4  * Copyright (c) 1995 Picture Elements
  5  *      Stephen Williams (steve@icarus.com)
  6  *      Gus Baldauf (gbaldauf@ix.netcom.com)
  7  *
  8  * Linux/SPARC port by Peter Zaitcev.
  9  * Integration into SPARC tree by Tom Dyas.
 10  */
 11 
 12 
 13 #include <linux/kernel.h>
 14 #include <linux/module.h>
 15 #include <linux/fs.h>
 16 #include <linux/errno.h>
 17 #include <linux/sched.h>
 18 #include <linux/smp_lock.h>
 19 #include <linux/spinlock.h>
 20 #include <linux/timer.h>
 21 #include <linux/ioport.h>
 22 #include <linux/major.h>
 23 #include <linux/devfs_fs_kernel.h>
 24 
 25 #include <asm/uaccess.h>
 26 #include <asm/io.h>
 27 
 28 #if defined(__i386__)
 29 # include <asm/system.h>
 30 #endif
 31 
 32 #if defined(__sparc__)
 33 # include <linux/init.h>
 34 # include <linux/delay.h>         /* udelay() */
 35 
 36 # include <asm/oplib.h>           /* OpenProm Library */
 37 # include <asm/sbus.h>
 38 #endif
 39 
 40 #include <asm/bpp.h>
 41 
 42 #define BPP_PROBE_CODE 0x55
 43 #define BPP_DELAY 100
 44 
 45 static const unsigned  BPP_MAJOR = LP_MAJOR;
 46 static const char* dev_name = "bpp";
 47 
 48 /* When switching from compatibility to a mode where I can read, try
 49    the following mode first. */
 50 
 51 /* const unsigned char DEFAULT_ECP = 0x10; */
 52 static const unsigned char DEFAULT_ECP = 0x30;
 53 static const unsigned char DEFAULT_NIBBLE = 0x00;
 54 
 55 /*
 56  * These are 1284 time constraints, in units of jiffies.
 57  */
 58 
 59 static const unsigned long TIME_PSetup = 1;
 60 static const unsigned long TIME_PResponse = 6;
 61 static const unsigned long TIME_IDLE_LIMIT = 2000;
 62 
 63 /*
 64  * One instance per supported subdevice...
 65  */
 66 # define BPP_NO 3
 67 
 68 enum IEEE_Mode { COMPATIBILITY, NIBBLE, ECP, ECP_RLE, EPP };
 69 
 70 struct inst {
 71       unsigned present  : 1; /* True if the hardware exists */
 72       unsigned enhanced : 1; /* True if the hardware in "enhanced" */
 73       unsigned opened   : 1; /* True if the device is opened already */
 74       unsigned run_flag : 1; /* True if waiting for a repeate byte */
 75 
 76       unsigned char direction; /* 0 --> out, 0x20 --> IN */
 77       unsigned char pp_state; /* State of host controlled pins. */
 78       enum IEEE_Mode mode;
 79 
 80       unsigned char run_length;
 81       unsigned char repeat_byte;
 82 
 83       /* These members manage timeouts for programmed delays */
 84       wait_queue_head_t wait_queue;
 85       struct timer_list timer_list;
 86 };
 87 
 88 static struct inst instances[BPP_NO];
 89 
 90 #if defined(__i386__)
 91 
 92 static const unsigned short base_addrs[BPP_NO] = { 0x278, 0x378, 0x3bc };
 93 
 94 /*
 95  * These are for data access.
 96  * Control lines accesses are hidden in set_bits() and get_bits().
 97  * The exception is the probe procedure, which is system-dependent.
 98  */
 99 #define bpp_outb_p(data, base)  outb_p((data), (base))
100 #define bpp_inb(base)  inb(base)
101 #define bpp_inb_p(base)  inb_p(base)
102 
103 /*
104  * This method takes the pin values mask and sets the hardware pins to
105  * the requested value: 1 == high voltage, 0 == low voltage. This
106  * burries the annoying PC bit inversion and preserves the direction
107  * flag.
108  */
109 static void set_pins(unsigned short pins, unsigned minor)
110 {
111       unsigned char bits = instances[minor].direction;  /* == 0x20 */
112 
113       if (! (pins & BPP_PP_nStrobe))   bits |= 1;
114       if (! (pins & BPP_PP_nAutoFd))   bits |= 2;
115       if (   pins & BPP_PP_nInit)      bits |= 4;
116       if (! (pins & BPP_PP_nSelectIn)) bits |= 8;
117 
118       instances[minor].pp_state = bits;
119 
120       outb_p(bits, base_addrs[minor]+2);
121 }
122 
123 static unsigned short get_pins(unsigned minor)
124 {
125       unsigned short bits = 0;
126 
127       unsigned value = instances[minor].pp_state;
128       if (! (value & 0x01)) bits |= BPP_PP_nStrobe;
129       if (! (value & 0x02)) bits |= BPP_PP_nAutoFd;
130       if (value & 0x04)     bits |= BPP_PP_nInit;
131       if (! (value & 0x08)) bits |= BPP_PP_nSelectIn;
132 
133       value = inb_p(base_addrs[minor]+1);
134       if (value & 0x08)     bits |= BPP_GP_nFault;
135       if (value & 0x10)     bits |= BPP_GP_Select;
136       if (value & 0x20)     bits |= BPP_GP_PError;
137       if (value & 0x40)     bits |= BPP_GP_nAck;
138       if (! (value & 0x80)) bits |= BPP_GP_Busy;
139 
140       return bits;
141 }
142 
143 #endif /* __i386__ */
144 
145 #if defined(__sparc__)
146 
147 /*
148  * Register block
149  */
150       /* DMA registers */
151 #define BPP_CSR      0x00
152 #define BPP_ADDR     0x04
153 #define BPP_BCNT     0x08
154 #define BPP_TST_CSR  0x0C
155       /* Parallel Port registers */
156 #define BPP_HCR      0x10
157 #define BPP_OCR      0x12
158 #define BPP_DR       0x14
159 #define BPP_TCR      0x15
160 #define BPP_OR       0x16
161 #define BPP_IR       0x17
162 #define BPP_ICR      0x18
163 #define BPP_SIZE     0x1A
164 
165 /* BPP_CSR.  Bits of type RW1 are cleared with writting '1'. */
166 #define P_DEV_ID_MASK   0xf0000000      /* R   */
167 #define P_DEV_ID_ZEBRA  0x40000000
168 #define P_DEV_ID_L64854 0xa0000000      /*      == NCR 89C100+89C105. Pity. */
169 #define P_NA_LOADED     0x08000000      /* R    NA wirtten but was not used */
170 #define P_A_LOADED      0x04000000      /* R    */
171 #define P_DMA_ON        0x02000000      /* R    DMA is not disabled */
172 #define P_EN_NEXT       0x01000000      /* RW   */
173 #define P_TCI_DIS       0x00800000      /* RW   TCI forbidden from interrupts */
174 #define P_DIAG          0x00100000      /* RW   Disables draining and resetting
175                                                 of P-FIFO on loading of P_ADDR*/
176 #define P_BURST_SIZE    0x000c0000      /* RW   SBus burst size */
177 #define P_BURST_8       0x00000000
178 #define P_BURST_4       0x00040000
179 #define P_BURST_1       0x00080000      /*      "No burst" write */
180 #define P_TC            0x00004000      /* RW1  Term Count, can be cleared when
181                                            P_EN_NEXT=1 */
182 #define P_EN_CNT        0x00002000      /* RW   */
183 #define P_EN_DMA        0x00000200      /* RW   */
184 #define P_WRITE         0x00000100      /* R    DMA dir, 1=to ram, 0=to port */
185 #define P_RESET         0x00000080      /* RW   */
186 #define P_SLAVE_ERR     0x00000040      /* RW1  Access size error */
187 #define P_INVALIDATE    0x00000020      /* W    Drop P-FIFO */
188 #define P_INT_EN        0x00000010      /* RW   OK to P_INT_PEND||P_ERR_PEND */
189 #define P_DRAINING      0x0000000c      /* R    P-FIFO is draining to memory */
190 #define P_ERR_PEND      0x00000002      /* R    */
191 #define P_INT_PEND      0x00000001      /* R    */
192 
193 /* BPP_HCR. Time is in increments of SBus clock. */
194 #define P_HCR_TEST      0x8000      /* Allows buried counters to be read */
195 #define P_HCR_DSW       0x7f00      /* Data strobe width (in ticks) */
196 #define P_HCR_DDS       0x007f      /* Data setup before strobe (in ticks) */
197 
198 /* BPP_OCR. */
199 #define P_OCR_MEM_CLR   0x8000
200 #define P_OCR_DATA_SRC  0x4000      /* )                  */
201 #define P_OCR_DS_DSEL   0x2000      /* )  Bidirectional      */
202 #define P_OCR_BUSY_DSEL 0x1000      /* )    selects            */
203 #define P_OCR_ACK_DSEL  0x0800      /* )                  */
204 #define P_OCR_EN_DIAG   0x0400
205 #define P_OCR_BUSY_OP   0x0200      /* Busy operation */
206 #define P_OCR_ACK_OP    0x0100      /* Ack operation */
207 #define P_OCR_SRST      0x0080      /* Reset state machines. Not selfcleaning. */
208 #define P_OCR_IDLE      0x0008      /* PP data transfer state machine is idle */
209 #define P_OCR_V_ILCK    0x0002      /* Versatec faded. Zebra only. */
210 #define P_OCR_EN_VER    0x0001      /* Enable Versatec (0 - enable). Zebra only. */
211 
212 /* BPP_TCR */
213 #define P_TCR_DIR       0x08
214 #define P_TCR_BUSY      0x04
215 #define P_TCR_ACK       0x02
216 #define P_TCR_DS        0x01        /* Strobe */
217 
218 /* BPP_OR */
219 #define P_OR_V3         0x20        /* )                 */
220 #define P_OR_V2         0x10        /* ) on Zebra only   */
221 #define P_OR_V1         0x08        /* )                 */
222 #define P_OR_INIT       0x04
223 #define P_OR_AFXN       0x02        /* Auto Feed */
224 #define P_OR_SLCT_IN    0x01
225 
226 /* BPP_IR */
227 #define P_IR_PE         0x04
228 #define P_IR_SLCT       0x02
229 #define P_IR_ERR        0x01
230 
231 /* BPP_ICR */
232 #define P_DS_IRQ        0x8000      /* RW1  */
233 #define P_ACK_IRQ       0x4000      /* RW1  */
234 #define P_BUSY_IRQ      0x2000      /* RW1  */
235 #define P_PE_IRQ        0x1000      /* RW1  */
236 #define P_SLCT_IRQ      0x0800      /* RW1  */
237 #define P_ERR_IRQ       0x0400      /* RW1  */
238 #define P_DS_IRQ_EN     0x0200      /* RW   Always on rising edge */
239 #define P_ACK_IRQ_EN    0x0100      /* RW   Always on rising edge */
240 #define P_BUSY_IRP      0x0080      /* RW   1= rising edge */
241 #define P_BUSY_IRQ_EN   0x0040      /* RW   */
242 #define P_PE_IRP        0x0020      /* RW   1= rising edge */
243 #define P_PE_IRQ_EN     0x0010      /* RW   */
244 #define P_SLCT_IRP      0x0008      /* RW   1= rising edge */
245 #define P_SLCT_IRQ_EN   0x0004      /* RW   */
246 #define P_ERR_IRP       0x0002      /* RW1  1= rising edge */
247 #define P_ERR_IRQ_EN    0x0001      /* RW   */
248 
249 static void __iomem *base_addrs[BPP_NO];
250 
251 #define bpp_outb_p(data, base)  sbus_writeb(data, (base) + BPP_DR)
252 #define bpp_inb_p(base)         sbus_readb((base) + BPP_DR)
253 #define bpp_inb(base)           sbus_readb((base) + BPP_DR)
254 
255 static void set_pins(unsigned short pins, unsigned minor)
256 {
257       void __iomem *base = base_addrs[minor];
258       unsigned char bits_tcr = 0, bits_or = 0;
259 
260       if (instances[minor].direction & 0x20) bits_tcr |= P_TCR_DIR;
261       if (   pins & BPP_PP_nStrobe)          bits_tcr |= P_TCR_DS;
262 
263       if (   pins & BPP_PP_nAutoFd)          bits_or |= P_OR_AFXN;
264       if (! (pins & BPP_PP_nInit))           bits_or |= P_OR_INIT;
265       if (! (pins & BPP_PP_nSelectIn))       bits_or |= P_OR_SLCT_IN;
266 
267       sbus_writeb(bits_or, base + BPP_OR);
268       sbus_writeb(bits_tcr, base + BPP_TCR);
269 }
270 
271 /*
272  * i386 people read output pins from a software image.
273  * We may get them back from hardware.
274  * Again, inversion of pins must he buried here.
275  */
276 static unsigned short get_pins(unsigned minor)
277 {
278       void __iomem *base = base_addrs[minor];
279       unsigned short bits = 0;
280       unsigned value_tcr = sbus_readb(base + BPP_TCR);
281       unsigned value_ir = sbus_readb(base + BPP_IR);
282       unsigned value_or = sbus_readb(base + BPP_OR);
283 
284       if (value_tcr & P_TCR_DS)         bits |= BPP_PP_nStrobe;
285       if (value_or & P_OR_AFXN)         bits |= BPP_PP_nAutoFd;
286       if (! (value_or & P_OR_INIT))     bits |= BPP_PP_nInit;
287       if (! (value_or & P_OR_SLCT_IN))  bits |= BPP_PP_nSelectIn;
288 
289       if (value_ir & P_IR_ERR)          bits |= BPP_GP_nFault;
290       if (! (value_ir & P_IR_SLCT))     bits |= BPP_GP_Select;
291       if (! (value_ir & P_IR_PE))       bits |= BPP_GP_PError;
292       if (! (value_tcr & P_TCR_ACK))    bits |= BPP_GP_nAck;
293       if (value_tcr & P_TCR_BUSY)       bits |= BPP_GP_Busy;
294 
295       return bits;
296 }
297 
298 #endif /* __sparc__ */
299 
300 static void bpp_wake_up(unsigned long val)
301 { wake_up(&instances[val].wait_queue); }
302 
303 static void snooze(unsigned long snooze_time, unsigned minor)
304 {
305       init_timer(&instances[minor].timer_list);
306       instances[minor].timer_list.expires = jiffies + snooze_time + 1;
307       instances[minor].timer_list.data    = minor;
308       add_timer(&instances[minor].timer_list);
309       sleep_on (&instances[minor].wait_queue);
310 }
311 
312 static int wait_for(unsigned short set, unsigned short clr,
313                unsigned long delay, unsigned minor)
314 {
315       unsigned short pins = get_pins(minor);
316 
317       unsigned long extime = 0;
318 
319       /*
320        * Try a real fast scan for the first jiffy, in case the device
321        * responds real good. The first while loop guesses an expire
322        * time accounting for possible wraparound of jiffies.
323        */
324       while (time_after_eq(jiffies, extime)) extime = jiffies + 1;
325       while ( (time_before(jiffies, extime))
326               && (((pins & set) != set) || ((pins & clr) != 0)) ) {
327             pins = get_pins(minor);
328       }
329 
330       delay -= 1;
331 
332       /*
333        * If my delay expired or the pins are still not where I want
334        * them, then resort to using the timer and greatly reduce my
335        * sample rate. If the peripheral is going to be slow, this will
336        * give the CPU up to some more worthy process.
337        */
338       while ( delay && (((pins & set) != set) || ((pins & clr) != 0)) ) {
339 
340             snooze(1, minor);
341             pins = get_pins(minor);
342             delay -= 1;
343       }
344 
345       if (delay == 0) return -1;
346       else return pins;
347 }
348 
349 /*
350  * Return ZERO(0) If the negotiation succeeds, an errno otherwise. An
351  * errno means something broke, and I do not yet know how to fix it.
352  */
353 static int negotiate(unsigned char mode, unsigned minor)
354 {
355       int rc;
356       unsigned short pins = get_pins(minor);
357       if (pins & BPP_PP_nSelectIn) return -EIO;
358 
359 
360         /* Event 0: Write the mode to the data lines */
361       bpp_outb_p(mode, base_addrs[minor]);
362 
363       snooze(TIME_PSetup, minor);
364 
365         /* Event 1: Strobe the mode code into the peripheral */
366       set_pins(BPP_PP_nSelectIn|BPP_PP_nStrobe|BPP_PP_nInit, minor);
367 
368         /* Wait for Event 2: Peripheral responds as a 1284 device. */
369       rc = wait_for(BPP_GP_PError|BPP_GP_Select|BPP_GP_nFault,
370                 BPP_GP_nAck,
371                 TIME_PResponse,
372                 minor);
373 
374       if (rc == -1) return -ETIMEDOUT;
375 
376         /* Event 3: latch extensibility request */
377       set_pins(BPP_PP_nSelectIn|BPP_PP_nInit, minor);
378 
379         /* ... quick nap while peripheral ponders the byte i'm sending...*/
380       snooze(1, minor);
381 
382         /* Event 4: restore strobe, to ACK peripheral's response. */
383       set_pins(BPP_PP_nSelectIn|BPP_PP_nAutoFd|BPP_PP_nStrobe|BPP_PP_nInit, minor);
384 
385         /* Wait for Event 6: Peripheral latches response bits */
386       rc = wait_for(BPP_GP_nAck, 0, TIME_PSetup+TIME_PResponse, minor);
387       if (rc == -1) return -EIO;
388 
389         /* A 1284 device cannot refuse nibble mode */
390       if (mode == DEFAULT_NIBBLE) return 0;
391 
392       if (pins & BPP_GP_Select) return 0;
393 
394       return -EPROTONOSUPPORT;
395 }
396 
397 static int terminate(unsigned minor)
398 {
399       int rc;
400 
401         /* Event 22: Request termination of 1284 mode */
402       set_pins(BPP_PP_nAutoFd|BPP_PP_nStrobe|BPP_PP_nInit, minor);
403 
404         /* Wait for Events 23 and 24: ACK termination request. */
405       rc = wait_for(BPP_GP_Busy|BPP_GP_nFault,
406                 BPP_GP_nAck,
407                 TIME_PSetup+TIME_PResponse,
408                 minor);
409 
410       instances[minor].direction = 0;
411       instances[minor].mode = COMPATIBILITY;
412 
413       if (rc == -1) {
414           return -EIO;
415       }
416 
417         /* Event 25: Handshake by lowering nAutoFd */
418       set_pins(BPP_PP_nStrobe|BPP_PP_nInit, minor);
419 
420         /* Event 26: Peripheral wiggles lines... */
421 
422         /* Event 27: Peripheral sets nAck HIGH to ack handshake */
423       rc = wait_for(BPP_GP_nAck, 0, TIME_PResponse, minor);
424       if (rc == -1) {
425           set_pins(BPP_PP_nAutoFd|BPP_PP_nStrobe|BPP_PP_nInit, minor);
426           return -EIO;
427       }
428 
429         /* Event 28: Finish phase by raising nAutoFd */
430       set_pins(BPP_PP_nAutoFd|BPP_PP_nStrobe|BPP_PP_nInit, minor);
431 
432       return 0;
433 }
434 
435 static DEFINE_SPINLOCK(bpp_open_lock);
436 
437 /*
438  * Allow only one process to open the device at a time.
439  */
440 static int bpp_open(struct inode *inode, struct file *f)
441 {
442       unsigned minor = iminor(inode);
443       int ret;
444 
445       spin_lock(&bpp_open_lock);
446       ret = 0;
447       if (minor >= BPP_NO) {
448               ret = -ENODEV;
449       } else {
450               if (! instances[minor].present) {
451                       ret = -ENODEV;
452               } else {
453                       if (instances[minor].opened) 
454                               ret = -EBUSY;
455                       else
456                               instances[minor].opened = 1;
457               }
458       }
459       spin_unlock(&bpp_open_lock);
460 
461       return ret;
462 }
463 
464 /*
465  * When the process closes the device, this method is called to clean
466  * up and reset the hardware. Always leave the device in compatibility
467  * mode as this is a reasonable place to clean up from messes made by
468  * ioctls, or other mayhem.
469  */
470 static int bpp_release(struct inode *inode, struct file *f)
471 {
472       unsigned minor = iminor(inode);
473 
474       spin_lock(&bpp_open_lock);
475       instances[minor].opened = 0;
476 
477       if (instances[minor].mode != COMPATIBILITY)
478               terminate(minor);
479 
480       spin_unlock(&bpp_open_lock);
481 
482       return 0;
483 }
484 
485 static long read_nibble(unsigned minor, char __user *c, unsigned long cnt)
486 {
487       unsigned long remaining = cnt;
488       long rc;
489 
490       while (remaining > 0) {
491           unsigned char byte = 0;
492           int pins;
493 
494           /* Event 7: request nibble */
495           set_pins(BPP_PP_nSelectIn|BPP_PP_nStrobe, minor);
496 
497           /* Wait for event 9: Peripher strobes first nibble */
498           pins = wait_for(0, BPP_GP_nAck, TIME_IDLE_LIMIT, minor);
499           if (pins == -1) return -ETIMEDOUT;
500 
501           /* Event 10: I handshake nibble */
502           set_pins(BPP_PP_nSelectIn|BPP_PP_nStrobe|BPP_PP_nAutoFd, minor);
503           if (pins & BPP_GP_nFault) byte |= 0x01;
504           if (pins & BPP_GP_Select) byte |= 0x02;
505           if (pins & BPP_GP_PError) byte |= 0x04;
506           if (pins & BPP_GP_Busy)   byte |= 0x08;
507 
508           /* Wait for event 11: Peripheral handshakes nibble */
509           rc = wait_for(BPP_GP_nAck, 0, TIME_PResponse, minor);
510 
511           /* Event 7: request nibble */
512           set_pins(BPP_PP_nSelectIn|BPP_PP_nStrobe, minor);
513 
514           /* Wait for event 9: Peripher strobes first nibble */
515           pins = wait_for(0, BPP_GP_nAck, TIME_PResponse, minor);
516           if (rc == -1) return -ETIMEDOUT;
517 
518           /* Event 10: I handshake nibble */
519           set_pins(BPP_PP_nSelectIn|BPP_PP_nStrobe|BPP_PP_nAutoFd, minor);
520           if (pins & BPP_GP_nFault) byte |= 0x10;
521           if (pins & BPP_GP_Select) byte |= 0x20;
522           if (pins & BPP_GP_PError) byte |= 0x40;
523           if (pins & BPP_GP_Busy)   byte |= 0x80;
524 
525           if (put_user(byte, c))
526                   return -EFAULT;
527           c += 1;
528           remaining -= 1;
529 
530           /* Wait for event 11: Peripheral handshakes nibble */
531           rc = wait_for(BPP_GP_nAck, 0, TIME_PResponse, minor);
532           if (rc == -1) return -EIO;
533       }
534 
535       return cnt - remaining;
536 }
537 
538 static long read_ecp(unsigned minor, char __user *c, unsigned long cnt)
539 {
540       unsigned long remaining;
541       long rc;
542 
543         /* Turn ECP mode from forward to reverse if needed. */
544       if (! instances[minor].direction) {
545           unsigned short pins = get_pins(minor);
546 
547             /* Event 38: Turn the bus around */
548           instances[minor].direction = 0x20;
549           pins &= ~BPP_PP_nAutoFd;
550           set_pins(pins, minor);
551 
552             /* Event 39: Set pins for reverse mode. */
553           snooze(TIME_PSetup, minor);
554           set_pins(BPP_PP_nStrobe|BPP_PP_nSelectIn, minor);
555 
556             /* Wait for event 40: Peripheral ready to be strobed */
557           rc = wait_for(0, BPP_GP_PError, TIME_PResponse, minor);
558           if (rc == -1) return -ETIMEDOUT;
559       }
560 
561       remaining = cnt;
562 
563       while (remaining > 0) {
564 
565             /* If there is a run length for a repeated byte, repeat */
566             /* that byte a few times. */
567           if (instances[minor].run_length && !instances[minor].run_flag) {
568 
569               char buffer[128];
570               unsigned idx;
571               unsigned repeat = remaining < instances[minor].run_length
572                                      ? remaining
573                                : instances[minor].run_length;
574 
575               for (idx = 0 ;  idx < repeat ;  idx += 1)
576                 buffer[idx] = instances[minor].repeat_byte;
577 
578               if (copy_to_user(c, buffer, repeat))
579                       return -EFAULT;
580               remaining -= repeat;
581               c += repeat;
582               instances[minor].run_length -= repeat;
583           }
584 
585           if (remaining == 0) break;
586 
587 
588             /* Wait for Event 43: Data active on the bus. */
589           rc = wait_for(0, BPP_GP_nAck, TIME_IDLE_LIMIT, minor);
590           if (rc == -1) break;
591 
592           if (rc & BPP_GP_Busy) {
593                 /* OK, this is data. read it in. */
594               unsigned char byte = bpp_inb(base_addrs[minor]);
595               if (put_user(byte, c))
596                       return -EFAULT;
597               c += 1;
598               remaining -= 1;
599 
600               if (instances[minor].run_flag) {
601                   instances[minor].repeat_byte = byte;
602                   instances[minor].run_flag = 0;
603               }
604 
605           } else {
606               unsigned char byte = bpp_inb(base_addrs[minor]);
607               if (byte & 0x80) {
608                   printk("bpp%d: "
609                          "Ignoring ECP channel %u from device.\n",
610                          minor, byte & 0x7f);
611               } else {
612                   instances[minor].run_length = byte;
613                   instances[minor].run_flag = 1;
614               }
615           }
616 
617             /* Event 44: I got it. */
618           set_pins(BPP_PP_nStrobe|BPP_PP_nAutoFd|BPP_PP_nSelectIn, minor);
619 
620             /* Wait for event 45: peripheral handshake */
621           rc = wait_for(BPP_GP_nAck, 0, TIME_PResponse, minor);
622           if (rc == -1) return -ETIMEDOUT;
623 
624              /* Event 46: Finish handshake */
625           set_pins(BPP_PP_nStrobe|BPP_PP_nSelectIn, minor);
626 
627       }
628 
629 
630       return cnt - remaining;
631 }
632 
633 static ssize_t bpp_read(struct file *f, char __user *c, size_t cnt, loff_t * ppos)
634 {
635       long rc;
636       unsigned minor = iminor(f->f_dentry->d_inode);
637       if (minor >= BPP_NO) return -ENODEV;
638       if (!instances[minor].present) return -ENODEV;
639 
640       switch (instances[minor].mode) {
641 
642         default:
643           if (instances[minor].mode != COMPATIBILITY)
644             terminate(minor);
645 
646           if (instances[minor].enhanced) {
647               /* For now, do all reads with ECP-RLE mode */
648               unsigned short pins;
649 
650               rc = negotiate(DEFAULT_ECP, minor);
651               if (rc < 0) break;
652 
653               instances[minor].mode = ECP_RLE;
654 
655               /* Event 30: set nAutoFd low to setup for ECP mode */
656               pins = get_pins(minor);
657               pins &= ~BPP_PP_nAutoFd;
658               set_pins(pins, minor);
659 
660               /* Wait for Event 31: peripheral ready */
661               rc = wait_for(BPP_GP_PError, 0, TIME_PResponse, minor);
662               if (rc == -1) return -ETIMEDOUT;
663 
664               rc = read_ecp(minor, c, cnt);
665 
666           } else {
667               rc = negotiate(DEFAULT_NIBBLE, minor);
668               if (rc < 0) break;
669 
670               instances[minor].mode = NIBBLE;
671 
672               rc = read_nibble(minor, c, cnt);
673           }
674           break;
675 
676         case NIBBLE:
677           rc = read_nibble(minor, c, cnt);
678           break;
679 
680         case ECP:
681         case ECP_RLE:
682           rc = read_ecp(minor, c, cnt);
683           break;
684 
685       }
686 
687 
688       return rc;
689 }
690 
691 /*
692  * Compatibility mode handshaking is a matter of writing data,
693  * strobing it, and waiting for the printer to stop being busy.
694  */
695 static long write_compat(unsigned minor, const char __user *c, unsigned long cnt)
696 {
697       long rc;
698       unsigned short pins = get_pins(minor);
699 
700       unsigned long remaining = cnt;
701 
702 
703       while (remaining > 0) {
704             unsigned char byte;
705 
706             if (get_user(byte, c))
707                     return -EFAULT;
708             c += 1;
709 
710             rc = wait_for(BPP_GP_nAck, BPP_GP_Busy, TIME_IDLE_LIMIT, minor);
711             if (rc == -1) return -ETIMEDOUT;
712 
713             bpp_outb_p(byte, base_addrs[minor]);
714             remaining -= 1;
715           /* snooze(1, minor); */
716 
717           pins &= ~BPP_PP_nStrobe;
718           set_pins(pins, minor);
719 
720           rc = wait_for(BPP_GP_Busy, 0, TIME_PResponse, minor);
721 
722           pins |= BPP_PP_nStrobe;
723           set_pins(pins, minor);
724       }
725 
726       return cnt - remaining;
727 }
728 
729 /*
730  * Write data using ECP mode. Watch out that the port may be set up
731  * for reading. If so, turn the port around.
732  */
733 static long write_ecp(unsigned minor, const char __user *c, unsigned long cnt)
734 {
735       unsigned short pins = get_pins(minor);
736       unsigned long remaining = cnt;
737 
738       if (instances[minor].direction) {
739           int rc;
740 
741             /* Event 47 Request bus be turned around */
742           pins |= BPP_PP_nInit;
743           set_pins(pins, minor);
744 
745             /* Wait for Event 49: Peripheral relinquished bus */
746           rc = wait_for(BPP_GP_PError, 0, TIME_PResponse, minor);
747 
748           pins |= BPP_PP_nAutoFd;
749           instances[minor].direction = 0;
750           set_pins(pins, minor);
751       }
752 
753       while (remaining > 0) {
754           unsigned char byte;
755           int rc;
756 
757           if (get_user(byte, c))
758                   return -EFAULT;
759 
760           rc = wait_for(0, BPP_GP_Busy, TIME_PResponse, minor);
761           if (rc == -1) return -ETIMEDOUT;
762 
763           c += 1;
764 
765           bpp_outb_p(byte, base_addrs[minor]);
766 
767           pins &= ~BPP_PP_nStrobe;
768           set_pins(pins, minor);
769 
770           pins |= BPP_PP_nStrobe;
771           rc = wait_for(BPP_GP_Busy, 0, TIME_PResponse, minor);
772           if (rc == -1) return -EIO;
773 
774           set_pins(pins, minor);
775       }
776 
777       return cnt - remaining;
778 }
779 
780 /*
781  * Write to the peripheral. Be sensitive of the current mode. If I'm
782  * in a mode that can be turned around (ECP) then just do
783  * that. Otherwise, terminate and do my writing in compat mode. This
784  * is the safest course as any device can handle it.
785  */
786 static ssize_t bpp_write(struct file *f, const char __user *c, size_t cnt, loff_t * ppos)
787 {
788       long errno = 0;
789       unsigned minor = iminor(f->f_dentry->d_inode);
790       if (minor >= BPP_NO) return -ENODEV;
791       if (!instances[minor].present) return -ENODEV;
792 
793       switch (instances[minor].mode) {
794 
795         case ECP:
796         case ECP_RLE:
797           errno = write_ecp(minor, c, cnt);
798           break;
799         case COMPATIBILITY:
800           errno = write_compat(minor, c, cnt);
801           break;
802         default:
803           terminate(minor);
804           errno = write_compat(minor, c, cnt);
805       }
806 
807       return errno;
808 }
809 
810 static int bpp_ioctl(struct inode *inode, struct file *f, unsigned int cmd,
811                  unsigned long arg)
812 {
813       int errno = 0;
814 
815       unsigned minor = iminor(inode);
816       if (minor >= BPP_NO) return -ENODEV;
817       if (!instances[minor].present) return -ENODEV;
818 
819 
820       switch (cmd) {
821 
822         case BPP_PUT_PINS:
823           set_pins(arg, minor);
824           break;
825 
826         case BPP_GET_PINS:
827           errno = get_pins(minor);
828           break;
829 
830         case BPP_PUT_DATA:
831           bpp_outb_p(arg, base_addrs[minor]);
832           break;
833 
834         case BPP_GET_DATA:
835           errno = bpp_inb_p(base_addrs[minor]);
836           break;
837 
838         case BPP_SET_INPUT:
839           if (arg)
840             if (instances[minor].enhanced) {
841                 unsigned short bits = get_pins(minor);
842                 instances[minor].direction = 0x20;
843                 set_pins(bits, minor);
844             } else {
845                 errno = -ENOTTY;
846             }
847           else {
848               unsigned short bits = get_pins(minor);
849               instances[minor].direction = 0x00;
850               set_pins(bits, minor);
851           }
852           break;
853 
854         default:
855             errno = -EINVAL;
856       }
857 
858       return errno;
859 }
860 
861 static struct file_operations bpp_fops = {
862         .owner =        THIS_MODULE,
863         .read =         bpp_read,
864         .write =        bpp_write,
865         .ioctl =        bpp_ioctl,
866         .open =         bpp_open,
867         .release =      bpp_release,
868 };
869 
870 #if defined(__i386__)
871 
872 #define collectLptPorts()  {}
873 
874 static void probeLptPort(unsigned idx)
875 {
876       unsigned int testvalue;
877       const unsigned short lpAddr = base_addrs[idx];
878 
879       instances[idx].present = 0;
880       instances[idx].enhanced = 0;
881       instances[idx].direction = 0;
882       instances[idx].mode = COMPATIBILITY;
883       instances[idx].wait_queue = 0;
884       instances[idx].run_length = 0;
885       instances[idx].run_flag = 0;
886       init_timer(&instances[idx].timer_list);
887       instances[idx].timer_list.function = bpp_wake_up;
888       if (!request_region(lpAddr,3, dev_name)) return;
889 
890       /*
891        * First, make sure the instance exists. Do this by writing to
892        * the data latch and reading the value back. If the port *is*
893        * present, test to see if it supports extended-mode
894        * operation. This will be required for IEEE1284 reverse
895        * transfers.
896        */
897 
898       outb_p(BPP_PROBE_CODE, lpAddr);
899       for (testvalue=0; testvalue<BPP_DELAY; testvalue++)
900             ;
901       testvalue = inb_p(lpAddr);
902       if (testvalue == BPP_PROBE_CODE) {
903             unsigned save;
904             instances[idx].present = 1;
905 
906             save = inb_p(lpAddr+2);
907             for (testvalue=0; testvalue<BPP_DELAY; testvalue++)
908                   ;
909             outb_p(save|0x20, lpAddr+2);
910             for (testvalue=0; testvalue<BPP_DELAY; testvalue++)
911                   ;
912             outb_p(~BPP_PROBE_CODE, lpAddr);
913             for (testvalue=0; testvalue<BPP_DELAY; testvalue++)
914                   ;
915             testvalue = inb_p(lpAddr);
916             if ((testvalue&0xff) == (0xff&~BPP_PROBE_CODE))
917                   instances[idx].enhanced = 0;
918             else
919                   instances[idx].enhanced = 1;
920             outb_p(save, lpAddr+2);
921       }
922       else {
923             release_region(lpAddr,3);
924       }
925       /*
926        * Leave the port in compat idle mode.
927        */
928       set_pins(BPP_PP_nAutoFd|BPP_PP_nStrobe|BPP_PP_nInit, idx);
929 
930       printk("bpp%d: Port at 0x%03x: Enhanced mode %s\n", idx, base_addrs[idx],
931             instances[idx].enhanced? "SUPPORTED" : "UNAVAILABLE");
932 }
933 
934 static inline void freeLptPort(int idx)
935 {
936       release_region(base_addrs[idx], 3);
937 }
938 
939 #endif
940 
941 #if defined(__sparc__)
942 
943 static void __iomem *map_bpp(struct sbus_dev *dev, int idx)
944 {
945       return sbus_ioremap(&dev->resource[0], 0, BPP_SIZE, "bpp");
946 }
947 
948 static int collectLptPorts(void)
949 {
950         struct sbus_bus *bus;
951         struct sbus_dev *dev;
952         int count;
953 
954         count = 0;
955         for_all_sbusdev(dev, bus) {
956                 if (strcmp(dev->prom_name, "SUNW,bpp") == 0) {
957                         if (count >= BPP_NO) {
958                                 printk(KERN_NOTICE
959                                        "bpp: More than %d bpp ports,"
960                                        " rest is ignored\n", BPP_NO);
961                                 return count;
962                         }
963                         base_addrs[count] = map_bpp(dev, count);
964                         count++;
965                 }
966         }
967         return count;
968 }
969 
970 static void probeLptPort(unsigned idx)
971 {
972       void __iomem *rp = base_addrs[idx];
973       __u32 csr;
974       char *brand;
975 
976       instances[idx].present = 0;
977       instances[idx].enhanced = 0;
978       instances[idx].direction = 0;
979       instances[idx].mode = COMPATIBILITY;
980       init_waitqueue_head(&instances[idx].wait_queue);
981       instances[idx].run_length = 0;
982       instances[idx].run_flag = 0;
983       init_timer(&instances[idx].timer_list);
984       instances[idx].timer_list.function = bpp_wake_up;
985 
986       if (!rp) return;
987 
988       instances[idx].present = 1;
989       instances[idx].enhanced = 1;   /* Sure */
990 
991       csr = sbus_readl(rp + BPP_CSR);
992       if ((csr & P_DRAINING) != 0 && (csr & P_ERR_PEND) == 0) {
993             udelay(20);
994             csr = sbus_readl(rp + BPP_CSR);
995             if ((csr & P_DRAINING) != 0 && (csr & P_ERR_PEND) == 0) {
996                   printk("bpp%d: DRAINING still active (0x%08x)\n", idx, csr);
997             }
998       }
999       printk("bpp%d: reset with 0x%08x ..", idx, csr);
1000       sbus_writel((csr | P_RESET) & ~P_INT_EN, rp + BPP_CSR);
1001       udelay(500);
1002       sbus_writel(sbus_readl(rp + BPP_CSR) & ~P_RESET, rp + BPP_CSR);
1003       csr = sbus_readl(rp + BPP_CSR);
1004       printk(" done with csr=0x%08x ocr=0x%04x\n",
1005          csr, sbus_readw(rp + BPP_OCR));
1006 
1007       switch (csr & P_DEV_ID_MASK) {
1008       case P_DEV_ID_ZEBRA:
1009             brand = "Zebra";
1010             break;
1011       case P_DEV_ID_L64854:
1012             brand = "DMA2";
1013             break;
1014       default:
1015             brand = "Unknown";
1016       }
1017       printk("bpp%d: %s at %p\n", idx, brand, rp);
1018 
1019       /*
1020        * Leave the port in compat idle mode.
1021        */
1022       set_pins(BPP_PP_nAutoFd|BPP_PP_nStrobe|BPP_PP_nInit, idx);
1023 
1024       return;
1025 }
1026 
1027 static inline void freeLptPort(int idx)
1028 {
1029       sbus_iounmap(base_addrs[idx], BPP_SIZE);
1030 }
1031 
1032 #endif
1033 
1034 static int __init bpp_init(void)
1035 {
1036         int rc;
1037         unsigned idx;
1038 
1039         rc = collectLptPorts();
1040         if (rc == 0)
1041                 return -ENODEV;
1042 
1043         rc = register_chrdev(BPP_MAJOR, dev_name, &bpp_fops);
1044         if (rc < 0)
1045                 return rc;
1046 
1047         for (idx = 0; idx < BPP_NO; idx++) {
1048                 instances[idx].opened = 0;
1049                 probeLptPort(idx);
1050         }
1051         devfs_mk_dir("bpp");
1052         for (idx = 0; idx < BPP_NO; idx++) {
1053                 devfs_mk_cdev(MKDEV(BPP_MAJOR, idx),
1054                                 S_IFCHR | S_IRUSR | S_IWUSR, "bpp/%d", idx);
1055         }
1056 
1057         return 0;
1058 }
1059 
1060 static void __exit bpp_cleanup(void)
1061 {
1062         unsigned idx;
1063 
1064         for (idx = 0; idx < BPP_NO; idx++)
1065                 devfs_remove("bpp/%d", idx);
1066         devfs_remove("bpp");
1067         unregister_chrdev(BPP_MAJOR, dev_name);
1068 
1069         for (idx = 0;  idx < BPP_NO; idx++) {
1070                 if (instances[idx].present)
1071                         freeLptPort(idx);
1072         }
1073 }
1074 
1075 module_init(bpp_init);
1076 module_exit(bpp_cleanup);
1077 
1078 MODULE_LICENSE("GPL");
1079 
1080 
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