aboutsummaryrefslogblamecommitdiffstats
path: root/drivers/net/irda/vlsi_ir.h
blob: c8b9c74eea524249c443a1e1faa28865ccd5e81d (plain) (tree)
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539










































                                                                          















































































































































































































































































































































































































































































































                                                                                                        

                                                                
               
                                                                               


                                                                               

                                               





















































































































































































                                                                                              
                                    



























                                                                 

/*********************************************************************
 *
 *	vlsi_ir.h:	VLSI82C147 PCI IrDA controller driver for Linux
 *
 *	Version:	0.5
 *
 *	Copyright (c) 2001-2003 Martin Diehl
 *
 *	This program is free software; you can redistribute it and/or 
 *	modify it under the terms of the GNU General Public License as 
 *	published by the Free Software Foundation; either version 2 of 
 *	the License, or (at your option) any later version.
 *
 *	This program is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *	GNU General Public License for more details.
 *
 *	You should have received a copy of the GNU General Public License 
 *	along with this program; if not, write to the Free Software 
 *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, 
 *	MA 02111-1307 USA
 *
 ********************************************************************/

#ifndef IRDA_VLSI_FIR_H
#define IRDA_VLSI_FIR_H

/* ================================================================
 * compatibility stuff
 */

/* definitions not present in pci_ids.h */

#ifndef PCI_CLASS_WIRELESS_IRDA
#define PCI_CLASS_WIRELESS_IRDA		0x0d00
#endif

#ifndef PCI_CLASS_SUBCLASS_MASK
#define PCI_CLASS_SUBCLASS_MASK		0xffff
#endif

/* ================================================================ */

/* non-standard PCI registers */

enum vlsi_pci_regs {
	VLSI_PCI_CLKCTL		= 0x40,		/* chip clock input control */
	VLSI_PCI_MSTRPAGE	= 0x41,		/* addr [31:24] for all busmaster cycles */
	VLSI_PCI_IRMISC		= 0x42		/* mainly legacy UART related */
};

/* ------------------------------------------ */

/* VLSI_PCI_CLKCTL: Clock Control Register (u8, rw) */

/* Three possible clock sources: either on-chip 48MHz PLL or
 * external clock applied to EXTCLK pin. External clock may
 * be either 48MHz or 40MHz, which is indicated by XCKSEL.
 * CLKSTP controls whether the selected clock source gets
 * connected to the IrDA block.
 *
 * On my HP OB-800 the BIOS sets external 40MHz clock as source
 * when IrDA enabled and I've never detected any PLL lock success.
 * Apparently the 14.3...MHz OSC input required for the PLL to work
 * is not connected and the 40MHz EXTCLK is provided externally.
 * At least this is what makes the driver working for me.
 */

enum vlsi_pci_clkctl {

	/* PLL control */

	CLKCTL_PD_INV		= 0x04,		/* PD#: inverted power down signal,
						 * i.e. PLL is powered, if PD_INV set */
	CLKCTL_LOCK		= 0x40,		/* (ro) set, if PLL is locked */

	/* clock source selection */

	CLKCTL_EXTCLK		= 0x20,		/* set to select external clock input, not PLL */
	CLKCTL_XCKSEL		= 0x10,		/* set to indicate EXTCLK is 40MHz, not 48MHz */

	/* IrDA block control */

	CLKCTL_CLKSTP		= 0x80,		/* set to disconnect from selected clock source */
	CLKCTL_WAKE		= 0x08		/* set to enable wakeup feature: whenever IR activity
						 * is detected, PD_INV gets set(?) and CLKSTP cleared */
};

/* ------------------------------------------ */

/* VLSI_PCI_MSTRPAGE: Master Page Register (u8, rw) and busmastering stuff */

#define DMA_MASK_USED_BY_HW	0xffffffff
#define DMA_MASK_MSTRPAGE	0x00ffffff
#define MSTRPAGE_VALUE		(DMA_MASK_MSTRPAGE >> 24)

	/* PCI busmastering is somewhat special for this guy - in short:
	 *
	 * We select to operate using fixed MSTRPAGE=0, use ISA DMA
	 * address restrictions to make the PCI BM api aware of this,
	 * but ensure the hardware is dealing with real 32bit access.
	 *
	 * In detail:
	 * The chip executes normal 32bit busmaster cycles, i.e.
	 * drives all 32 address lines. These addresses however are
	 * composed of [0:23] taken from various busaddr-pointers
	 * and [24:31] taken from the MSTRPAGE register in the VLSI82C147
	 * config space. Therefore _all_ busmastering must be
	 * targeted to/from one single 16MB (busaddr-) superpage!
	 * The point is to make sure all the allocations for memory
	 * locations with busmaster access (ring descriptors, buffers)
	 * are indeed bus-mappable to the same 16MB range (for x86 this
	 * means they must reside in the same 16MB physical memory address
	 * range). The only constraint we have which supports "several objects
	 * mappable to common 16MB range" paradigma, is the old ISA DMA
	 * restriction to the first 16MB of physical address range.
	 * Hence the approach here is to enable PCI busmaster support using
	 * the correct 32bit dma-mask used by the chip. Afterwards the device's
	 * dma-mask gets restricted to 24bit, which must be honoured somehow by
	 * all allocations for memory areas to be exposed to the chip ...
	 *
	 * Note:
	 * Don't be surprised to get "Setting latency timer..." messages every
	 * time when PCI busmastering is enabled for the chip.
	 * The chip has its PCI latency timer RO fixed at 0 - which is not a
	 * problem here, because it is never requesting _burst_ transactions.
	 */

/* ------------------------------------------ */

/* VLSI_PCIIRMISC: IR Miscellaneous Register (u8, rw) */

/* legacy UART emulation - not used by this driver - would require:
 * (see below for some register-value definitions)
 *
 *	- IRMISC_UARTEN must be set to enable UART address decoding
 *	- IRMISC_UARTSEL configured
 *	- IRCFG_MASTER must be cleared
 *	- IRCFG_SIR must be set
 *	- IRENABLE_PHYANDCLOCK must be asserted 0->1 (and hence IRENABLE_SIR_ON)
 */

enum vlsi_pci_irmisc {

	/* IR transceiver control */

	IRMISC_IRRAIL		= 0x40,		/* (ro?) IR rail power indication (and control?)
						 * 0=3.3V / 1=5V. Probably set during power-on?
						 * unclear - not touched by driver */
	IRMISC_IRPD		= 0x08,		/* transceiver power down, if set */

	/* legacy UART control */

	IRMISC_UARTTST		= 0x80,		/* UART test mode - "always write 0" */
	IRMISC_UARTEN		= 0x04,		/* enable UART address decoding */

	/* bits [1:0] IRMISC_UARTSEL to select legacy UART address */

	IRMISC_UARTSEL_3f8	= 0x00,
	IRMISC_UARTSEL_2f8	= 0x01,
	IRMISC_UARTSEL_3e8	= 0x02,
	IRMISC_UARTSEL_2e8	= 0x03
};

/* ================================================================ */

/* registers mapped to 32 byte PCI IO space */

/* note: better access all registers at the indicated u8/u16 size
 *	 although some of them contain only 1 byte of information.
 *	 some of them (particaluarly PROMPT and IRCFG) ignore
 *	 access when using the wrong addressing mode!
 */

enum vlsi_pio_regs {
	VLSI_PIO_IRINTR		= 0x00,		/* interrupt enable/request (u8, rw) */
	VLSI_PIO_RINGPTR	= 0x02,		/* rx/tx ring pointer (u16, ro) */
	VLSI_PIO_RINGBASE	= 0x04,		/* [23:10] of ring address (u16, rw) */
	VLSI_PIO_RINGSIZE	= 0x06,		/* rx/tx ring size (u16, rw) */
	VLSI_PIO_PROMPT		= 0x08, 	/* triggers ring processing (u16, wo) */
	/* 0x0a-0x0f: reserved / duplicated UART regs */
	VLSI_PIO_IRCFG		= 0x10,		/* configuration select (u16, rw) */
	VLSI_PIO_SIRFLAG	= 0x12,		/* BOF/EOF for filtered SIR (u16, ro) */
	VLSI_PIO_IRENABLE	= 0x14,		/* enable and status register (u16, rw/ro) */
	VLSI_PIO_PHYCTL		= 0x16,		/* physical layer current status (u16, ro) */
	VLSI_PIO_NPHYCTL	= 0x18,		/* next physical layer select (u16, rw) */
	VLSI_PIO_MAXPKT		= 0x1a,		/* [11:0] max len for packet receive (u16, rw) */
	VLSI_PIO_RCVBCNT	= 0x1c		/* current receive-FIFO byte count (u16, ro) */
	/* 0x1e-0x1f: reserved / duplicated UART regs */
};

/* ------------------------------------------ */

/* VLSI_PIO_IRINTR: Interrupt Register (u8, rw) */

/* enable-bits:
 *		1 = enable / 0 = disable
 * interrupt condition bits:
 * 		set according to corresponding interrupt source
 *		(regardless of the state of the enable bits)
 *		enable bit status indicates whether interrupt gets raised
 *		write-to-clear
 * note: RPKTINT and TPKTINT behave different in legacy UART mode (which we don't use :-)
 */

enum vlsi_pio_irintr {
	IRINTR_ACTEN	= 0x80,	/* activity interrupt enable */
	IRINTR_ACTIVITY	= 0x40,	/* activity monitor (traffic detected) */
	IRINTR_RPKTEN	= 0x20,	/* receive packet interrupt enable*/
	IRINTR_RPKTINT	= 0x10,	/* rx-packet transfered from fifo to memory finished */
	IRINTR_TPKTEN	= 0x08,	/* transmit packet interrupt enable */
	IRINTR_TPKTINT	= 0x04,	/* last bit of tx-packet+crc shifted to ir-pulser */
	IRINTR_OE_EN	= 0x02,	/* UART rx fifo overrun error interrupt enable */
	IRINTR_OE_INT	= 0x01	/* UART rx fifo overrun error (read LSR to clear) */
};

/* we use this mask to check whether the (shared PCI) interrupt is ours */

#define IRINTR_INT_MASK		(IRINTR_ACTIVITY|IRINTR_RPKTINT|IRINTR_TPKTINT)

/* ------------------------------------------ */

/* VLSI_PIO_RINGPTR: Ring Pointer Read-Back Register (u16, ro) */

/* _both_ ring pointers are indices relative to the _entire_ rx,tx-ring!
 * i.e. the referenced descriptor is located
 * at RINGBASE + PTR * sizeof(descr) for rx and tx
 * therefore, the tx-pointer has offset MAX_RING_DESCR
 */

#define MAX_RING_DESCR		64	/* tx, rx rings may contain up to 64 descr each */

#define RINGPTR_RX_MASK		(MAX_RING_DESCR-1)
#define RINGPTR_TX_MASK		((MAX_RING_DESCR-1)<<8)

#define RINGPTR_GET_RX(p)	((p)&RINGPTR_RX_MASK)
#define RINGPTR_GET_TX(p)	(((p)&RINGPTR_TX_MASK)>>8)

/* ------------------------------------------ */

/* VLSI_PIO_RINGBASE: Ring Pointer Base Address Register (u16, ro) */

/* Contains [23:10] part of the ring base (bus-) address
 * which must be 1k-alinged. [31:24] is taken from
 * VLSI_PCI_MSTRPAGE above.
 * The controller initiates non-burst PCI BM cycles to
 * fetch and update the descriptors in the ring.
 * Once fetched, the descriptor remains cached onchip
 * until it gets closed and updated due to the ring
 * processing state machine.
 * The entire ring area is split in rx and tx areas with each
 * area consisting of 64 descriptors of 8 bytes each.
 * The rx(tx) ring is located at ringbase+0 (ringbase+64*8).
 */

#define BUS_TO_RINGBASE(p)	(((p)>>10)&0x3fff)

/* ------------------------------------------ */

/* VLSI_PIO_RINGSIZE: Ring Size Register (u16, rw) */

/* bit mask to indicate the ring size to be used for rx and tx.
 * 	possible values		encoded bits
 *		 4		   0000
 *		 8		   0001
 *		16		   0011
 *		32		   0111
 *		64		   1111
 * located at [15:12] for tx and [11:8] for rx ([7:0] unused)
 *
 * note: probably a good idea to have IRCFG_MSTR cleared when writing
 *	 this so the state machines are stopped and the RINGPTR is reset!
 */

#define SIZE_TO_BITS(num)		((((num)-1)>>2)&0x0f)
#define TX_RX_TO_RINGSIZE(tx,rx)	((SIZE_TO_BITS(tx)<<12)|(SIZE_TO_BITS(rx)<<8))
#define RINGSIZE_TO_RXSIZE(rs)		((((rs)&0x0f00)>>6)+4)
#define RINGSIZE_TO_TXSIZE(rs)		((((rs)&0xf000)>>10)+4)


/* ------------------------------------------ */

/* VLSI_PIO_PROMPT: Ring Prompting Register (u16, write-to-start) */

/* writing any value kicks the ring processing state machines
 * for both tx, rx rings as follows:
 * 	- active rings (currently owning an active descriptor)
 *	  ignore the prompt and continue
 *	- idle rings fetch the next descr from the ring and start
 *	  their processing
 */

/* ------------------------------------------ */

/* VLSI_PIO_IRCFG: IR Config Register (u16, rw) */

/* notes:
 *	- not more than one SIR/MIR/FIR bit must be set at any time
 *	- SIR, MIR, FIR and CRC16 select the configuration which will
 *	  be applied on next 0->1 transition of IRENABLE_PHYANDCLOCK (see below).
 *	- besides allowing the PCI interface to execute busmaster cycles
 *	  and therefore the ring SM to operate, the MSTR bit has side-effects:
 *	  when MSTR is cleared, the RINGPTR's get reset and the legacy UART mode
 *	  (in contrast to busmaster access mode) gets enabled.
 *	- clearing ENRX or setting ENTX while data is received may stall the
 *	  receive fifo until ENRX reenabled _and_ another packet arrives
 *	- SIRFILT means the chip performs the required unwrapping of hardware
 *	  headers (XBOF's, BOF/EOF) and un-escaping in the _receive_ direction.
 *	  Only the resulting IrLAP payload is copied to the receive buffers -
 *	  but with the 16bit FCS still encluded. Question remains, whether it
 *	  was already checked or we should do it before passing the packet to IrLAP?
 */

enum vlsi_pio_ircfg {
	IRCFG_LOOP	= 0x4000,	/* enable loopback test mode */
	IRCFG_ENTX	= 0x1000,	/* transmit enable */
	IRCFG_ENRX	= 0x0800,	/* receive enable */
	IRCFG_MSTR	= 0x0400,	/* master enable */
	IRCFG_RXANY	= 0x0200,	/* receive any packet */
	IRCFG_CRC16	= 0x0080,	/* 16bit (not 32bit) CRC select for MIR/FIR */
	IRCFG_FIR	= 0x0040,	/* FIR 4PPM encoding mode enable */
	IRCFG_MIR	= 0x0020,	/* MIR HDLC encoding mode enable */
	IRCFG_SIR	= 0x0010,	/* SIR encoding mode enable */
	IRCFG_SIRFILT	= 0x0008,	/* enable SIR decode filter (receiver unwrapping) */
	IRCFG_SIRTEST	= 0x0004,	/* allow SIR decode filter when not in SIR mode */
	IRCFG_TXPOL	= 0x0002,	/* invert tx polarity when set */
	IRCFG_RXPOL	= 0x0001	/* invert rx polarity when set */
};

/* ------------------------------------------ */

/* VLSI_PIO_SIRFLAG: SIR Flag Register (u16, ro) */

/* register contains hardcoded BOF=0xc0 at [7:0] and EOF=0xc1 at [15:8]
 * which is used for unwrapping received frames in SIR decode-filter mode
 */

/* ------------------------------------------ */

/* VLSI_PIO_IRENABLE: IR Enable Register (u16, rw/ro) */

/* notes:
 *	- IREN acts as gate for latching the configured IR mode information
 *	  from IRCFG and IRPHYCTL when IREN=reset and applying them when
 *	  IREN gets set afterwards.
 *	- ENTXST reflects IRCFG_ENTX
 *	- ENRXST = IRCFG_ENRX && (!IRCFG_ENTX || IRCFG_LOOP)
 */

enum vlsi_pio_irenable {
	IRENABLE_PHYANDCLOCK	= 0x8000,  /* enable IR phy and gate the mode config (rw) */
	IRENABLE_CFGER		= 0x4000,  /* mode configuration error (ro) */
	IRENABLE_FIR_ON		= 0x2000,  /* FIR on status (ro) */
	IRENABLE_MIR_ON		= 0x1000,  /* MIR on status (ro) */
	IRENABLE_SIR_ON		= 0x0800,  /* SIR on status (ro) */
	IRENABLE_ENTXST		= 0x0400,  /* transmit enable status (ro) */
	IRENABLE_ENRXST		= 0x0200,  /* Receive enable status (ro) */
	IRENABLE_CRC16_ON	= 0x0100   /* 16bit (not 32bit) CRC enabled status (ro) */
};

#define	  IRENABLE_MASK	    0xff00  /* Read mask */

/* ------------------------------------------ */

/* VLSI_PIO_PHYCTL: IR Physical Layer Current Control Register (u16, ro) */

/* read-back of the currently applied physical layer status.
 * applied from VLSI_PIO_NPHYCTL at rising edge of IRENABLE_PHYANDCLOCK
 * contents identical to VLSI_PIO_NPHYCTL (see below)
 */

/* ------------------------------------------ */

/* VLSI_PIO_NPHYCTL: IR Physical Layer Next Control Register (u16, rw) */

/* latched during IRENABLE_PHYANDCLOCK=0 and applied at 0-1 transition
 *
 * consists of BAUD[15:10], PLSWID[9:5] and PREAMB[4:0] bits defined as follows:
 *
 * SIR-mode:	BAUD = (115.2kHz / baudrate) - 1
 *		PLSWID = (pulsetime * freq / (BAUD+1)) - 1
 *			where pulsetime is the requested IrPHY pulse width
 *			and freq is 8(16)MHz for 40(48)MHz primary input clock
 *		PREAMB: don't care for SIR
 *
 *		The nominal SIR pulse width is 3/16 bit time so we have PLSWID=12
 *		fixed for all SIR speeds at 40MHz input clock (PLSWID=24 at 48MHz).
 *		IrPHY also allows shorter pulses down to the nominal pulse duration
 *		at 115.2kbaud (minus some tolerance) which is 1.41 usec.
 *		Using the expression PLSWID = 12/(BAUD+1)-1 (multiplied by two for 48MHz)
 *		we get the minimum acceptable PLSWID values according to the VLSI
 *		specification, which provides 1.5 usec pulse width for all speeds (except
 *		for 2.4kbaud getting 6usec). This is fine with IrPHY v1.3 specs and
 *		reduces the transceiver power which drains the battery. At 9.6kbaud for
 *		example this amounts to more than 90% battery power saving!
 *
 * MIR-mode:	BAUD = 0
 *		PLSWID = 9(10) for 40(48) MHz input clock
 *			to get nominal MIR pulse width
 *		PREAMB = 1
 *
 * FIR-mode:	BAUD = 0
 *		PLSWID: don't care
 *		PREAMB = 15
 */

#define PHYCTL_BAUD_SHIFT	10
#define PHYCTL_BAUD_MASK	0xfc00
#define PHYCTL_PLSWID_SHIFT	5
#define PHYCTL_PLSWID_MASK	0x03e0
#define PHYCTL_PREAMB_SHIFT	0
#define PHYCTL_PREAMB_MASK	0x001f

#define PHYCTL_TO_BAUD(bwp)	(((bwp)&PHYCTL_BAUD_MASK)>>PHYCTL_BAUD_SHIFT)
#define PHYCTL_TO_PLSWID(bwp)	(((bwp)&PHYCTL_PLSWID_MASK)>>PHYCTL_PLSWID_SHIFT)
#define PHYCTL_TO_PREAMB(bwp)	(((bwp)&PHYCTL_PREAMB_MASK)>>PHYCTL_PREAMB_SHIFT)

#define BWP_TO_PHYCTL(b,w,p)	((((b)<<PHYCTL_BAUD_SHIFT)&PHYCTL_BAUD_MASK) \
				 | (((w)<<PHYCTL_PLSWID_SHIFT)&PHYCTL_PLSWID_MASK) \
				 | (((p)<<PHYCTL_PREAMB_SHIFT)&PHYCTL_PREAMB_MASK))

#define BAUD_BITS(br)		((115200/(br))-1)

static inline unsigned
calc_width_bits(unsigned baudrate, unsigned widthselect, unsigned clockselect)
{
	unsigned	tmp;

	if (widthselect)	/* nominal 3/16 puls width */
		return (clockselect) ? 12 : 24;

	tmp = ((clockselect) ? 12 : 24) / (BAUD_BITS(baudrate)+1);

	/* intermediate result of integer division needed here */

	return (tmp>0) ? (tmp-1) : 0;
}

#define PHYCTL_SIR(br,ws,cs)	BWP_TO_PHYCTL(BAUD_BITS(br),calc_width_bits((br),(ws),(cs)),0)
#define PHYCTL_MIR(cs)		BWP_TO_PHYCTL(0,((cs)?9:10),1)
#define PHYCTL_FIR		BWP_TO_PHYCTL(0,0,15)

/* quite ugly, I know. But implementing these calculations here avoids
 * having magic numbers in the code and allows some playing with pulsewidths
 * without risk to violate the standards.
 * FWIW, here is the table for reference:
 *
 * baudrate	BAUD	min-PLSWID	nom-PLSWID	PREAMB
 *     2400	  47	   0(0)		   12(24)	   0
 *     9600	  11	   0(0)		   12(24)	   0
 *    19200	   5	   1(2)		   12(24)	   0
 *    38400	   2	   3(6)	           12(24)	   0
 *    57600	   1	   5(10)	   12(24)	   0
 *   115200	   0	  11(22)	   12(24)	   0
 *	MIR	   0	    -		    9(10)	   1
 *	FIR	   0        -               0		  15
 *
 * note: x(y) means x-value for 40MHz / y-value for 48MHz primary input clock
 */

/* ------------------------------------------ */


/* VLSI_PIO_MAXPKT: Maximum Packet Length register (u16, rw) */

/* maximum acceptable length for received packets */

/* hw imposed limitation - register uses only [11:0] */
#define MAX_PACKET_LENGTH	0x0fff

/* IrLAP I-field (apparently not defined elsewhere) */
#define IRDA_MTU		2048

/* complete packet consists of A(1)+C(1)+I(<=IRDA_MTU) */
#define IRLAP_SKB_ALLOCSIZE	(1+1+IRDA_MTU)

/* the buffers we use to exchange frames with the hardware need to be
 * larger than IRLAP_SKB_ALLOCSIZE because we may have up to 4 bytes FCS
 * appended and, in SIR mode, a lot of frame wrapping bytes. The worst
 * case appears to be a SIR packet with I-size==IRDA_MTU and all bytes
 * requiring to be escaped to provide transparency. Furthermore, the peer
 * might ask for quite a number of additional XBOFs:
 *	up to 115+48 XBOFS		 163
 *	regular BOF			   1
 *	A-field				   1
 *	C-field				   1
 *	I-field, IRDA_MTU, all escaped	4096
 *	FCS (16 bit at SIR, escaped)	   4
 *	EOF				   1
 * AFAICS nothing in IrLAP guarantees A/C field not to need escaping
 * (f.e. 0xc0/0xc1 - i.e. BOF/EOF - are legal values there) so in the
 * worst case we have 4269 bytes total frame size.
 * However, the VLSI uses 12 bits only for all buffer length values,
 * which limits the maximum useable buffer size <= 4095.
 * Note this is not a limitation in the receive case because we use
 * the SIR filtering mode where the hw unwraps the frame and only the
 * bare packet+fcs is stored into the buffer - in contrast to the SIR
 * tx case where we have to pass frame-wrapped packets to the hw.
 * If this would ever become an issue in real life, the only workaround
 * I see would be using the legacy UART emulation in SIR mode.
 */

#define XFER_BUF_SIZE		MAX_PACKET_LENGTH

/* ------------------------------------------ */

/* VLSI_PIO_RCVBCNT: Receive Byte Count Register (u16, ro) */

/* receive packet counter gets incremented on every non-filtered
 * byte which was put in the receive fifo and reset for each
 * new packet. Used to decide whether we are just in the middle
 * of receiving
 */

/* better apply the [11:0] mask when reading, as some docs say the
 * reserved [15:12] would return 1 when reading - which is wrong AFAICS
 */
#define RCVBCNT_MASK	0x0fff

/******************************************************************/

/* descriptors for rx/tx ring
 *
 * accessed by hardware - don't change!
 *
 * the descriptor is owned by hardware, when the ACTIVE status bit
 * is set and nothing (besides reading status to test the bit)
 * shall be done. The bit gets cleared by hw, when the descriptor
 * gets closed. Premature reaping of descriptors owned be the chip
 * can be achieved by disabling IRCFG_MSTR
 *
 * Attention: Writing addr overwrites status!
 *
 * ### FIXME: depends on endianess (but there ain't no non-i586 ob800 ;-)
 */

struct ring_descr_hw {
	volatile __le16	rd_count;	/* tx/rx count [11:0] */
	__le16		reserved;
	union {
		__le32	addr;		/* [23:0] of the buffer's busaddress */
		struct {
			u8		addr_res[3];
			volatile u8	status;		/* descriptor status */
		} __attribute__((packed)) rd_s;
	} __attribute((packed)) rd_u;
} __attribute__ ((packed));

#define rd_addr		rd_u.addr
#define rd_status	rd_u.rd_s.status

/* ring descriptor status bits */

#define RD_ACTIVE		0x80	/* descriptor owned by hw (both TX,RX) */

/* TX ring descriptor status */

#define	RD_TX_DISCRC		0x40	/* do not send CRC (for SIR) */
#define	RD_TX_BADCRC		0x20	/* force a bad CRC */
#define	RD_TX_PULSE		0x10	/* send indication pulse after this frame (MIR/FIR) */
#define	RD_TX_FRCEUND		0x08	/* force underrun */
#define	RD_TX_CLRENTX		0x04	/* clear ENTX after this frame */
#define	RD_TX_UNDRN		0x01	/* TX fifo underrun (probably PCI problem) */

/* RX ring descriptor status */

#define RD_RX_PHYERR		0x40	/* physical encoding error */
#define RD_RX_CRCERR		0x20	/* CRC error (MIR/FIR) */
#define RD_RX_LENGTH		0x10	/* frame exceeds buffer length */
#define RD_RX_OVER		0x08	/* RX fifo overrun (probably PCI problem) */
#define RD_RX_SIRBAD		0x04	/* EOF missing: BOF follows BOF (SIR, filtered) */

#define RD_RX_ERROR		0x7c	/* any error in received frame */

/* the memory required to hold the 2 descriptor rings */
#define HW_RING_AREA_SIZE	(2 * MAX_RING_DESCR * sizeof(struct ring_descr_hw))

/******************************************************************/

/* sw-ring descriptors consists of a bus-mapped transfer buffer with
 * associated skb and a pointer to the hw entry descriptor
 */

struct ring_descr {
	struct ring_descr_hw	*hw;
	struct sk_buff		*skb;
	void			*buf;
};

/* wrappers for operations on hw-exposed ring descriptors
 * access to the hw-part of the descriptors must use these.
 */

static inline int rd_is_active(struct ring_descr *rd)
{
	return ((rd->hw->rd_status & RD_ACTIVE) != 0);
}

static inline void rd_activate(struct ring_descr *rd)
{
	rd->hw->rd_status |= RD_ACTIVE;
}

static inline void rd_set_status(struct ring_descr *rd, u8 s)
{
	rd->hw->rd_status = s;	 /* may pass ownership to the hardware */
}

static inline void rd_set_addr_status(struct ring_descr *rd, dma_addr_t a, u8 s)
{
	/* order is important for two reasons:
	 *  - overlayed: writing addr overwrites status
	 *  - we want to write status last so we have valid address in
	 *    case status has RD_ACTIVE set
	 */

	if ((a & ~DMA_MASK_MSTRPAGE)>>24 != MSTRPAGE_VALUE) {
		IRDA_ERROR("%s: pci busaddr inconsistency!\n", __FUNCTION__);
		dump_stack();
		return;
	}

	a &= DMA_MASK_MSTRPAGE;  /* clear highbyte to make sure we won't write
				  * to status - just in case MSTRPAGE_VALUE!=0
				  */
	rd->hw->rd_addr = cpu_to_le32(a);
	wmb();
	rd_set_status(rd, s);	 /* may pass ownership to the hardware */
}

static inline void rd_set_count(struct ring_descr *rd, u16 c)
{
	rd->hw->rd_count = cpu_to_le16(c);
}

static inline u8 rd_get_status(struct ring_descr *rd)
{
	return rd->hw->rd_status;
}

static inline dma_addr_t rd_get_addr(struct ring_descr *rd)
{
	dma_addr_t	a;

	a = le32_to_cpu(rd->hw->rd_addr);
	return (a & DMA_MASK_MSTRPAGE) | (MSTRPAGE_VALUE << 24);
}

static inline u16 rd_get_count(struct ring_descr *rd)
{
	return le16_to_cpu(rd->hw->rd_count);
}

/******************************************************************/

/* sw descriptor rings for rx, tx:
 *
 * operations follow producer-consumer paradigm, with the hw
 * in the middle doing the processing.
 * ring size must be power of two.
 *
 * producer advances r->tail after inserting for processing
 * consumer advances r->head after removing processed rd
 * ring is empty if head==tail / full if (tail+1)==head
 */

struct vlsi_ring {
	struct pci_dev		*pdev;
	int			dir;
	unsigned		len;
	unsigned		size;
	unsigned		mask;
	atomic_t		head, tail;
	struct ring_descr	*rd;
};

/* ring processing helpers */

static inline struct ring_descr *ring_last(struct vlsi_ring *r)
{
	int t;

	t = atomic_read(&r->tail) & r->mask;
	return (((t+1) & r->mask) == (atomic_read(&r->head) & r->mask)) ? NULL : &r->rd[t];
}

static inline struct ring_descr *ring_put(struct vlsi_ring *r)
{
	atomic_inc(&r->tail);
	return ring_last(r);
}

static inline struct ring_descr *ring_first(struct vlsi_ring *r)
{
	int h;

	h = atomic_read(&r->head) & r->mask;
	return (h == (atomic_read(&r->tail) & r->mask)) ? NULL : &r->rd[h];
}

static inline struct ring_descr *ring_get(struct vlsi_ring *r)
{
	atomic_inc(&r->head);
	return ring_first(r);
}

/******************************************************************/

/* our private compound VLSI-PCI-IRDA device information */

typedef struct vlsi_irda_dev {
	struct pci_dev		*pdev;
	struct net_device_stats	stats;

	struct irlap_cb		*irlap;

	struct qos_info		qos;

	unsigned		mode;
	int			baud, new_baud;

	dma_addr_t		busaddr;
	void			*virtaddr;
	struct vlsi_ring	*tx_ring, *rx_ring;

	struct timeval		last_rx;

	spinlock_t		lock;
	struct mutex		mtx;

	u8			resume_ok;	
	struct proc_dir_entry	*proc_entry;

} vlsi_irda_dev_t;

/********************************************************/

/* the remapped error flags we use for returning from frame
 * post-processing in vlsi_process_tx/rx() after it was completed
 * by the hardware. These functions either return the >=0 number
 * of transfered bytes in case of success or the negative (-)
 * of the or'ed error flags.
 */

#define VLSI_TX_DROP		0x0001
#define VLSI_TX_FIFO		0x0002

#define VLSI_RX_DROP		0x0100
#define VLSI_RX_OVER		0x0200
#define VLSI_RX_LENGTH  	0x0400
#define VLSI_RX_FRAME		0x0800
#define VLSI_RX_CRC		0x1000

/********************************************************/

#endif /* IRDA_VLSI_FIR_H */