1 /*********************************************************************
5 * Description: IrLAP QoS parameter negotiation
7 * Author: Dag Brattli <dagb@cs.uit.no>
8 * Created at: Tue Sep 9 00:00:26 1997
9 * Modified at: Sun Jan 30 14:29:16 2000
10 * Modified by: Dag Brattli <dagb@cs.uit.no>
12 * Copyright (c) 1998-2000 Dag Brattli <dagb@cs.uit.no>,
13 * All Rights Reserved.
14 * Copyright (c) 2000-2001 Jean Tourrilhes <jt@hpl.hp.com>
16 * This program is free software; you can redistribute it and/or
17 * modify it under the terms of the GNU General Public License as
18 * published by the Free Software Foundation; either version 2 of
19 * the License, or (at your option) any later version.
21 * This program is distributed in the hope that it will be useful,
22 * but WITHOUT ANY WARRANTY; without even the implied warranty of
23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
24 * GNU General Public License for more details.
26 * You should have received a copy of the GNU General Public License
27 * along with this program; if not, write to the Free Software
28 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
31 ********************************************************************/
33 #include <linux/export.h>
35 #include <asm/byteorder.h>
37 #include <net/irda/irda.h>
38 #include <net/irda/parameters.h>
39 #include <net/irda/qos.h>
40 #include <net/irda/irlap.h>
41 #include <net/irda/irlap_frame.h>
44 * Maximum values of the baud rate we negotiate with the other end.
45 * Most often, you don't have to change that, because Linux-IrDA will
46 * use the maximum offered by the link layer, which usually works fine.
47 * In some very rare cases, you may want to limit it to lower speeds...
49 int sysctl_max_baud_rate = 16000000;
51 * Maximum value of the lap disconnect timer we negotiate with the other end.
52 * Most often, the value below represent the best compromise, but some user
53 * may want to keep the LAP alive longer or shorter in case of link failure.
54 * Remember that the threshold time (early warning) is fixed to 3s...
56 int sysctl_max_noreply_time = 12;
58 * Minimum turn time to be applied before transmitting to the peer.
59 * Nonzero values (usec) are used as lower limit to the per-connection
60 * mtt value which was announced by the other end during negotiation.
61 * Might be helpful if the peer device provides too short mtt.
62 * Default is 10us which means using the unmodified value given by the
63 * peer except if it's 0 (0 is likely a bug in the other stack).
65 unsigned int sysctl_min_tx_turn_time = 10;
67 * Maximum data size to be used in transmission in payload of LAP frame.
68 * There is a bit of confusion in the IrDA spec :
69 * The LAP spec defines the payload of a LAP frame (I field) to be
70 * 2048 bytes max (IrLAP 1.1, chapt 6.6.5, p40).
71 * On the other hand, the PHY mention frames of 2048 bytes max (IrPHY
72 * 1.2, chapt 5.3.2.1, p41). But, this number includes the LAP header
73 * (2 bytes), and CRC (32 bits at 4 Mb/s). So, for the I field (LAP
74 * payload), that's only 2042 bytes. Oups !
75 * My nsc-ircc hardware has troubles receiving 2048 bytes frames at 4 Mb/s,
76 * so adjust to 2042... I don't know if this bug applies only for 2048
77 * bytes frames or all negotiated frame sizes, but you can use the sysctl
78 * to play with this value anyway.
80 unsigned int sysctl_max_tx_data_size = 2042;
82 * Maximum transmit window, i.e. number of LAP frames between turn-around.
83 * This allow to override what the peer told us. Some peers are buggy and
84 * don't always support what they tell us.
86 unsigned int sysctl_max_tx_window = 7;
88 static int irlap_param_baud_rate(void *instance, irda_param_t *param, int get);
89 static int irlap_param_link_disconnect(void *instance, irda_param_t *parm,
91 static int irlap_param_max_turn_time(void *instance, irda_param_t *param,
93 static int irlap_param_data_size(void *instance, irda_param_t *param, int get);
94 static int irlap_param_window_size(void *instance, irda_param_t *param,
96 static int irlap_param_additional_bofs(void *instance, irda_param_t *parm,
98 static int irlap_param_min_turn_time(void *instance, irda_param_t *param,
101 #ifndef CONFIG_IRDA_DYNAMIC_WINDOW
102 static __u32 irlap_requested_line_capacity(struct qos_info *qos);
105 static __u32 min_turn_times[] = { 10000, 5000, 1000, 500, 100, 50, 10, 0 }; /* us */
106 static __u32 baud_rates[] = { 2400, 9600, 19200, 38400, 57600, 115200, 576000,
107 1152000, 4000000, 16000000 }; /* bps */
108 static __u32 data_sizes[] = { 64, 128, 256, 512, 1024, 2048 }; /* bytes */
109 static __u32 add_bofs[] = { 48, 24, 12, 5, 3, 2, 1, 0 }; /* bytes */
110 static __u32 max_turn_times[] = { 500, 250, 100, 50 }; /* ms */
111 static __u32 link_disc_times[] = { 3, 8, 12, 16, 20, 25, 30, 40 }; /* secs */
113 static __u32 max_line_capacities[10][4] = {
114 /* 500 ms 250 ms 100 ms 50 ms (max turn time) */
115 { 100, 0, 0, 0 }, /* 2400 bps */
116 { 400, 0, 0, 0 }, /* 9600 bps */
117 { 800, 0, 0, 0 }, /* 19200 bps */
118 { 1600, 0, 0, 0 }, /* 38400 bps */
119 { 2360, 0, 0, 0 }, /* 57600 bps */
120 { 4800, 2400, 960, 480 }, /* 115200 bps */
121 { 28800, 11520, 5760, 2880 }, /* 576000 bps */
122 { 57600, 28800, 11520, 5760 }, /* 1152000 bps */
123 { 200000, 100000, 40000, 20000 }, /* 4000000 bps */
124 { 800000, 400000, 160000, 80000 }, /* 16000000 bps */
127 static pi_minor_info_t pi_minor_call_table_type_0[] = {
129 /* 01 */{ irlap_param_baud_rate, PV_INTEGER | PV_LITTLE_ENDIAN },
136 /* 08 */{ irlap_param_link_disconnect, PV_INT_8_BITS }
139 static pi_minor_info_t pi_minor_call_table_type_1[] = {
142 /* 82 */{ irlap_param_max_turn_time, PV_INT_8_BITS },
143 /* 83 */{ irlap_param_data_size, PV_INT_8_BITS },
144 /* 84 */{ irlap_param_window_size, PV_INT_8_BITS },
145 /* 85 */{ irlap_param_additional_bofs, PV_INT_8_BITS },
146 /* 86 */{ irlap_param_min_turn_time, PV_INT_8_BITS },
149 static pi_major_info_t pi_major_call_table[] = {
150 { pi_minor_call_table_type_0, 9 },
151 { pi_minor_call_table_type_1, 7 },
154 static pi_param_info_t irlap_param_info = { pi_major_call_table, 2, 0x7f, 7 };
156 /* ---------------------- LOCAL SUBROUTINES ---------------------- */
157 /* Note : we start with a bunch of local subroutines.
158 * As the compiler is "one pass", this is the only way to get them to
163 * Function value_index (value, array, size)
165 * Returns the index to the value in the specified array
167 static inline int value_index(__u32 value, __u32 *array, int size)
171 for (i=0; i < size; i++)
172 if (array[i] == value)
178 * Function index_value (index, array)
180 * Returns value to index in array, easy!
183 static inline __u32 index_value(int index, __u32 *array)
189 * Function msb_index (word)
191 * Returns index to most significant bit (MSB) in word
194 static int msb_index (__u16 word)
197 int index = 15; /* Current MSB */
199 /* Check for buggy peers.
200 * Note : there is a small probability that it could be us, but I
201 * would expect driver authors to catch that pretty early and be
202 * able to check precisely what's going on. If a end user sees this,
203 * it's very likely the peer. - Jean II */
205 IRDA_WARNING("%s(), Detected buggy peer, adjust null PV to 0x1!\n",
207 /* The only safe choice (we don't know the array size) */
213 break; /* Found it! */
221 * Function value_lower_bits (value, array)
223 * Returns a bit field marking all possibility lower than value.
225 static inline int value_lower_bits(__u32 value, __u32 *array, int size, __u16 *field)
231 for (i=0; i < size; i++) {
232 /* Add the current value to the bit field, shift mask */
236 if (array[i] >= value)
239 /* Send back a valid index */
241 i = size - 1; /* Last item */
247 * Function value_highest_bit (value, array)
249 * Returns a bit field marking the highest possibility lower than value.
251 static inline int value_highest_bit(__u32 value, __u32 *array, int size, __u16 *field)
257 for (i=0; i < size; i++) {
259 if (array[i] <= value)
264 /* Set the current value to the bit field */
266 /* Send back a valid index */
268 i = size - 1; /* Last item */
273 /* -------------------------- MAIN CALLS -------------------------- */
276 * Function irda_qos_compute_intersection (qos, new)
278 * Compute the intersection of the old QoS capabilities with new ones
281 void irda_qos_compute_intersection(struct qos_info *qos, struct qos_info *new)
283 IRDA_ASSERT(qos != NULL, return;);
284 IRDA_ASSERT(new != NULL, return;);
287 qos->baud_rate.bits &= new->baud_rate.bits;
288 qos->window_size.bits &= new->window_size.bits;
289 qos->min_turn_time.bits &= new->min_turn_time.bits;
290 qos->max_turn_time.bits &= new->max_turn_time.bits;
291 qos->data_size.bits &= new->data_size.bits;
292 qos->link_disc_time.bits &= new->link_disc_time.bits;
293 qos->additional_bofs.bits &= new->additional_bofs.bits;
295 irda_qos_bits_to_value(qos);
299 * Function irda_init_max_qos_capabilies (qos)
301 * The purpose of this function is for layers and drivers to be able to
302 * set the maximum QoS possible and then "and in" their own limitations
305 void irda_init_max_qos_capabilies(struct qos_info *qos)
309 * These are the maximum supported values as specified on pages
313 /* Use sysctl to set some configurable values... */
314 /* Set configured max speed */
315 i = value_lower_bits(sysctl_max_baud_rate, baud_rates, 10,
316 &qos->baud_rate.bits);
317 sysctl_max_baud_rate = index_value(i, baud_rates);
319 /* Set configured max disc time */
320 i = value_lower_bits(sysctl_max_noreply_time, link_disc_times, 8,
321 &qos->link_disc_time.bits);
322 sysctl_max_noreply_time = index_value(i, link_disc_times);
324 /* LSB is first byte, MSB is second byte */
325 qos->baud_rate.bits &= 0x03ff;
327 qos->window_size.bits = 0x7f;
328 qos->min_turn_time.bits = 0xff;
329 qos->max_turn_time.bits = 0x0f;
330 qos->data_size.bits = 0x3f;
331 qos->link_disc_time.bits &= 0xff;
332 qos->additional_bofs.bits = 0xff;
334 EXPORT_SYMBOL(irda_init_max_qos_capabilies);
337 * Function irlap_adjust_qos_settings (qos)
339 * Adjust QoS settings in case some values are not possible to use because
342 static void irlap_adjust_qos_settings(struct qos_info *qos)
347 IRDA_DEBUG(2, "%s()\n", __func__);
350 * Make sure the mintt is sensible.
351 * Main culprit : Ericsson T39. - Jean II
353 if (sysctl_min_tx_turn_time > qos->min_turn_time.value) {
356 IRDA_WARNING("%s(), Detected buggy peer, adjust mtt to %dus!\n",
357 __func__, sysctl_min_tx_turn_time);
359 /* We don't really need bits, but easier this way */
360 i = value_highest_bit(sysctl_min_tx_turn_time, min_turn_times,
361 8, &qos->min_turn_time.bits);
362 sysctl_min_tx_turn_time = index_value(i, min_turn_times);
363 qos->min_turn_time.value = sysctl_min_tx_turn_time;
367 * Not allowed to use a max turn time less than 500 ms if the baudrate
368 * is less than 115200
370 if ((qos->baud_rate.value < 115200) &&
371 (qos->max_turn_time.value < 500))
374 "%s(), adjusting max turn time from %d to 500 ms\n",
375 __func__, qos->max_turn_time.value);
376 qos->max_turn_time.value = 500;
380 * The data size must be adjusted according to the baud rate and max
383 index = value_index(qos->data_size.value, data_sizes, 6);
384 line_capacity = irlap_max_line_capacity(qos->baud_rate.value,
385 qos->max_turn_time.value);
387 #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
388 while ((qos->data_size.value > line_capacity) && (index > 0)) {
389 qos->data_size.value = data_sizes[index--];
390 IRDA_DEBUG(2, "%s(), reducing data size to %d\n",
391 __func__, qos->data_size.value);
393 #else /* Use method described in section 6.6.11 of IrLAP */
394 while (irlap_requested_line_capacity(qos) > line_capacity) {
395 IRDA_ASSERT(index != 0, return;);
397 /* Must be able to send at least one frame */
398 if (qos->window_size.value > 1) {
399 qos->window_size.value--;
400 IRDA_DEBUG(2, "%s(), reducing window size to %d\n",
401 __func__, qos->window_size.value);
402 } else if (index > 1) {
403 qos->data_size.value = data_sizes[index--];
404 IRDA_DEBUG(2, "%s(), reducing data size to %d\n",
405 __func__, qos->data_size.value);
407 IRDA_WARNING("%s(), nothing more we can do!\n",
411 #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
413 * Fix tx data size according to user limits - Jean II
415 if (qos->data_size.value > sysctl_max_tx_data_size)
416 /* Allow non discrete adjustement to avoid losing capacity */
417 qos->data_size.value = sysctl_max_tx_data_size;
419 * Override Tx window if user request it. - Jean II
421 if (qos->window_size.value > sysctl_max_tx_window)
422 qos->window_size.value = sysctl_max_tx_window;
426 * Function irlap_negotiate (qos_device, qos_session, skb)
428 * Negotiate QoS values, not really that much negotiation :-)
429 * We just set the QoS capabilities for the peer station
432 int irlap_qos_negotiate(struct irlap_cb *self, struct sk_buff *skb)
436 ret = irda_param_extract_all(self, skb->data, skb->len,
439 /* Convert the negotiated bits to values */
440 irda_qos_bits_to_value(&self->qos_tx);
441 irda_qos_bits_to_value(&self->qos_rx);
443 irlap_adjust_qos_settings(&self->qos_tx);
445 IRDA_DEBUG(2, "Setting BAUD_RATE to %d bps.\n",
446 self->qos_tx.baud_rate.value);
447 IRDA_DEBUG(2, "Setting DATA_SIZE to %d bytes\n",
448 self->qos_tx.data_size.value);
449 IRDA_DEBUG(2, "Setting WINDOW_SIZE to %d\n",
450 self->qos_tx.window_size.value);
451 IRDA_DEBUG(2, "Setting XBOFS to %d\n",
452 self->qos_tx.additional_bofs.value);
453 IRDA_DEBUG(2, "Setting MAX_TURN_TIME to %d ms.\n",
454 self->qos_tx.max_turn_time.value);
455 IRDA_DEBUG(2, "Setting MIN_TURN_TIME to %d usecs.\n",
456 self->qos_tx.min_turn_time.value);
457 IRDA_DEBUG(2, "Setting LINK_DISC to %d secs.\n",
458 self->qos_tx.link_disc_time.value);
463 * Function irlap_insert_negotiation_params (qos, fp)
465 * Insert QoS negotiaion pararameters into frame
468 int irlap_insert_qos_negotiation_params(struct irlap_cb *self,
473 /* Insert data rate */
474 ret = irda_param_insert(self, PI_BAUD_RATE, skb_tail_pointer(skb),
475 skb_tailroom(skb), &irlap_param_info);
480 /* Insert max turnaround time */
481 ret = irda_param_insert(self, PI_MAX_TURN_TIME, skb_tail_pointer(skb),
482 skb_tailroom(skb), &irlap_param_info);
487 /* Insert data size */
488 ret = irda_param_insert(self, PI_DATA_SIZE, skb_tail_pointer(skb),
489 skb_tailroom(skb), &irlap_param_info);
494 /* Insert window size */
495 ret = irda_param_insert(self, PI_WINDOW_SIZE, skb_tail_pointer(skb),
496 skb_tailroom(skb), &irlap_param_info);
501 /* Insert additional BOFs */
502 ret = irda_param_insert(self, PI_ADD_BOFS, skb_tail_pointer(skb),
503 skb_tailroom(skb), &irlap_param_info);
508 /* Insert minimum turnaround time */
509 ret = irda_param_insert(self, PI_MIN_TURN_TIME, skb_tail_pointer(skb),
510 skb_tailroom(skb), &irlap_param_info);
515 /* Insert link disconnect/threshold time */
516 ret = irda_param_insert(self, PI_LINK_DISC, skb_tail_pointer(skb),
517 skb_tailroom(skb), &irlap_param_info);
526 * Function irlap_param_baud_rate (instance, param, get)
528 * Negotiate data-rate
531 static int irlap_param_baud_rate(void *instance, irda_param_t *param, int get)
535 struct irlap_cb *self = (struct irlap_cb *) instance;
537 IRDA_ASSERT(self != NULL, return -1;);
538 IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);
541 param->pv.i = self->qos_rx.baud_rate.bits;
542 IRDA_DEBUG(2, "%s(), baud rate = 0x%02x\n",
543 __func__, param->pv.i);
546 * Stations must agree on baud rate, so calculate
549 IRDA_DEBUG(2, "Requested BAUD_RATE: 0x%04x\n", (__u16) param->pv.i);
550 final = (__u16) param->pv.i & self->qos_rx.baud_rate.bits;
552 IRDA_DEBUG(2, "Final BAUD_RATE: 0x%04x\n", final);
553 self->qos_tx.baud_rate.bits = final;
554 self->qos_rx.baud_rate.bits = final;
561 * Function irlap_param_link_disconnect (instance, param, get)
563 * Negotiate link disconnect/threshold time.
566 static int irlap_param_link_disconnect(void *instance, irda_param_t *param,
571 struct irlap_cb *self = (struct irlap_cb *) instance;
573 IRDA_ASSERT(self != NULL, return -1;);
574 IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);
577 param->pv.i = self->qos_rx.link_disc_time.bits;
580 * Stations must agree on link disconnect/threshold
583 IRDA_DEBUG(2, "LINK_DISC: %02x\n", (__u8) param->pv.i);
584 final = (__u8) param->pv.i & self->qos_rx.link_disc_time.bits;
586 IRDA_DEBUG(2, "Final LINK_DISC: %02x\n", final);
587 self->qos_tx.link_disc_time.bits = final;
588 self->qos_rx.link_disc_time.bits = final;
594 * Function irlap_param_max_turn_time (instance, param, get)
596 * Negotiate the maximum turnaround time. This is a type 1 parameter and
597 * will be negotiated independently for each station
600 static int irlap_param_max_turn_time(void *instance, irda_param_t *param,
603 struct irlap_cb *self = (struct irlap_cb *) instance;
605 IRDA_ASSERT(self != NULL, return -1;);
606 IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);
609 param->pv.i = self->qos_rx.max_turn_time.bits;
611 self->qos_tx.max_turn_time.bits = (__u8) param->pv.i;
617 * Function irlap_param_data_size (instance, param, get)
619 * Negotiate the data size. This is a type 1 parameter and
620 * will be negotiated independently for each station
623 static int irlap_param_data_size(void *instance, irda_param_t *param, int get)
625 struct irlap_cb *self = (struct irlap_cb *) instance;
627 IRDA_ASSERT(self != NULL, return -1;);
628 IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);
631 param->pv.i = self->qos_rx.data_size.bits;
633 self->qos_tx.data_size.bits = (__u8) param->pv.i;
639 * Function irlap_param_window_size (instance, param, get)
641 * Negotiate the window size. This is a type 1 parameter and
642 * will be negotiated independently for each station
645 static int irlap_param_window_size(void *instance, irda_param_t *param,
648 struct irlap_cb *self = (struct irlap_cb *) instance;
650 IRDA_ASSERT(self != NULL, return -1;);
651 IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);
654 param->pv.i = self->qos_rx.window_size.bits;
656 self->qos_tx.window_size.bits = (__u8) param->pv.i;
662 * Function irlap_param_additional_bofs (instance, param, get)
664 * Negotiate additional BOF characters. This is a type 1 parameter and
665 * will be negotiated independently for each station.
667 static int irlap_param_additional_bofs(void *instance, irda_param_t *param, int get)
669 struct irlap_cb *self = (struct irlap_cb *) instance;
671 IRDA_ASSERT(self != NULL, return -1;);
672 IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);
675 param->pv.i = self->qos_rx.additional_bofs.bits;
677 self->qos_tx.additional_bofs.bits = (__u8) param->pv.i;
683 * Function irlap_param_min_turn_time (instance, param, get)
685 * Negotiate the minimum turn around time. This is a type 1 parameter and
686 * will be negotiated independently for each station
688 static int irlap_param_min_turn_time(void *instance, irda_param_t *param,
691 struct irlap_cb *self = (struct irlap_cb *) instance;
693 IRDA_ASSERT(self != NULL, return -1;);
694 IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);
697 param->pv.i = self->qos_rx.min_turn_time.bits;
699 self->qos_tx.min_turn_time.bits = (__u8) param->pv.i;
705 * Function irlap_max_line_capacity (speed, max_turn_time, min_turn_time)
707 * Calculate the maximum line capacity
710 __u32 irlap_max_line_capacity(__u32 speed, __u32 max_turn_time)
715 IRDA_DEBUG(2, "%s(), speed=%d, max_turn_time=%d\n",
716 __func__, speed, max_turn_time);
718 i = value_index(speed, baud_rates, 10);
719 j = value_index(max_turn_time, max_turn_times, 4);
721 IRDA_ASSERT(((i >=0) && (i <10)), return 0;);
722 IRDA_ASSERT(((j >=0) && (j <4)), return 0;);
724 line_capacity = max_line_capacities[i][j];
726 IRDA_DEBUG(2, "%s(), line capacity=%d bytes\n",
727 __func__, line_capacity);
729 return line_capacity;
732 #ifndef CONFIG_IRDA_DYNAMIC_WINDOW
733 static __u32 irlap_requested_line_capacity(struct qos_info *qos)
737 line_capacity = qos->window_size.value *
738 (qos->data_size.value + 6 + qos->additional_bofs.value) +
739 irlap_min_turn_time_in_bytes(qos->baud_rate.value,
740 qos->min_turn_time.value);
742 IRDA_DEBUG(2, "%s(), requested line capacity=%d\n",
743 __func__, line_capacity);
745 return line_capacity;
749 void irda_qos_bits_to_value(struct qos_info *qos)
753 IRDA_ASSERT(qos != NULL, return;);
755 index = msb_index(qos->baud_rate.bits);
756 qos->baud_rate.value = baud_rates[index];
758 index = msb_index(qos->data_size.bits);
759 qos->data_size.value = data_sizes[index];
761 index = msb_index(qos->window_size.bits);
762 qos->window_size.value = index+1;
764 index = msb_index(qos->min_turn_time.bits);
765 qos->min_turn_time.value = min_turn_times[index];
767 index = msb_index(qos->max_turn_time.bits);
768 qos->max_turn_time.value = max_turn_times[index];
770 index = msb_index(qos->link_disc_time.bits);
771 qos->link_disc_time.value = link_disc_times[index];
773 index = msb_index(qos->additional_bofs.bits);
774 qos->additional_bofs.value = add_bofs[index];
776 EXPORT_SYMBOL(irda_qos_bits_to_value);