summaryrefslogtreecommitdiffstats
path: root/src/target/firmware/layer1/prim_rach.c
blob: e6ea6568cd7bb5ea8044121dfb3842d4c3a88a54 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
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
/* Layer 1 Random Access Channel Burst */

/* (C) 2010 by Dieter Spaar <spaar@mirider.augusta.de>
 * (C) 2010 by Harald Welte <laforge@gnumonks.org>
 *
 * All Rights Reserved
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */

#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include <defines.h>
#include <debug.h>
#include <memory.h>
#include <byteorder.h>
#include <osmocom/gsm/gsm_utils.h>
#include <osmocom/core/msgb.h>
#include <calypso/dsp_api.h>
#include <calypso/irq.h>
#include <calypso/tpu.h>
#include <calypso/tsp.h>
#include <calypso/dsp.h>
#include <calypso/timer.h>
#include <comm/sercomm.h>
#include <asm/system.h>

#include <layer1/sync.h>
#include <layer1/async.h>
#include <layer1/tdma_sched.h>
#include <layer1/tpu_window.h>
#include <layer1/l23_api.h>
#include <layer1/sched_gsmtime.h>

#include <l1ctl_proto.h>

struct {
	uint32_t fn;
	uint16_t band_arfcn;
} last_rach;

/* p1: type of operation (0: one NB, 1: one RACH burst, 2: four NB */
static int l1s_tx_rach_cmd(__unused uint8_t p1, __unused uint8_t p2, __unused uint16_t p3)
{
	uint16_t  *info_ptr;
	uint16_t arfcn;
	uint8_t data[2];

	putchart('T');

	l1s_tx_apc_helper(l1s.serving_cell.arfcn);

	data[0] = l1s.serving_cell.bsic << 2;
	data[1] = l1s.rach.ra;

	info_ptr = &dsp_api.ndb->d_rach;
	info_ptr[0] = ((uint16_t)(data[0])) | ((uint16_t)(data[1])<<8);

	arfcn = l1s.serving_cell.arfcn;

	dsp_api.db_w->d_task_ra = dsp_task_iq_swap(RACH_DSP_TASK, arfcn, 1);

	l1s_tx_win_ctrl(arfcn | ARFCN_UPLINK, L1_TXWIN_AB, 0, 3);

	return 0;
}

/* p1: type of operation (0: one NB, 1: one RACH burst, 2: four NB */
static int l1s_tx_rach_resp(__unused uint8_t p1, __unused uint8_t burst_id,
			    __unused uint16_t p3)
{
	putchart('t');

	dsp_api.r_page_used = 1;

	/* schedule a confirmation back indicating the GSM time at which
	 * the RACH burst was transmitted to the BTS */
	last_rach.fn = l1s.current_time.fn - 1;
	last_rach.band_arfcn = l1s.serving_cell.arfcn;
	l1s_compl_sched(L1_COMPL_RACH);

	return 0;
}

/* sched sets for uplink */
const struct tdma_sched_item rach_sched_set_ul[] = {
	SCHED_ITEM_DT(l1s_tx_rach_cmd, 3, 1, 0),	SCHED_END_FRAME(),
							SCHED_END_FRAME(),
	SCHED_ITEM(l1s_tx_rach_resp, -4, 1, 0),		SCHED_END_FRAME(),
	SCHED_END_SET()
};

/* Asynchronous completion handler for FB detection */
static void l1a_rach_compl(__unused enum l1_compl c)
{
	struct msgb *msg;

	msg = l1_create_l2_msg(L1CTL_RACH_CONF, last_rach.fn, 0,
				last_rach.band_arfcn);
	l1_queue_for_l2(msg);
}

static uint8_t t3_to_rach_comb[51] = {
	 0,  0,  0,  0,
	 0,  1,
	 2,  2,  2,  2,  2,  2,  2,  2,
	 2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12,
	13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
	25, 25, 25, 25, 25, 25, 25, 25,
	25, 26,
	27, 27, 27, 27};
static uint8_t rach_to_t3_comb[27] = {
	 4,  5,
	14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
	25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,
	45, 46};

/* request a RACH request at the next multiframe T3 = fn51 */
void l1a_rach_req(uint16_t offset, uint8_t combined, uint8_t ra)
{
	uint32_t fn_sched;
	unsigned long flags;

	offset += 3;

	local_firq_save(flags);
	if (combined) {
		/* add elapsed RACH slots to offset */
		offset += t3_to_rach_comb[l1s.current_time.t3];
		/* offset is the number of RACH slots in the future */
		fn_sched = l1s.current_time.fn - l1s.current_time.t3;
		fn_sched += offset / 27 * 51;
		fn_sched += rach_to_t3_comb[offset % 27];
	} else
		fn_sched = l1s.current_time.fn + offset;
	l1s.rach.ra = ra;
	sched_gsmtime(rach_sched_set_ul, fn_sched, 0);
	local_irq_restore(flags);

	memset(&last_rach, 0, sizeof(last_rach));
}

static __attribute__ ((constructor)) void prim_rach_init(void)
{
	l1s.completion[L1_COMPL_RACH] = &l1a_rach_compl;
}