osmocom-bb/src/target/firmware/layer1/prim_rach.c

163 lines
4.3 KiB
C

/* 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;
}