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

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/* Synchronous part of GSM Layer 1 */
/* (C) 2010 by Harald Welte <laforge@gnumonks.org>
* (C) 2010 by Dieter Spaar <spaar@mirider.augusta.de>
* (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.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 <asm/system.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 <abb/twl3025.h>
//#define DEBUG_EVERY_TDMA
#include <layer1/sync.h>
#include <layer1/afc.h>
#include <layer1/agc.h>
#include <layer1/apc.h>
#include <layer1/tdma_sched.h>
#include <layer1/mframe_sched.h>
#include <layer1/sched_gsmtime.h>
#include <layer1/tpu_window.h>
#include <layer1/l23_api.h>
#include <l1ctl_proto.h>
struct l1s_state l1s;
void l1s_time_inc(struct gsm_time *time, uint32_t delta_fn)
{
ADD_MODULO(time->fn, delta_fn, GSM_MAX_FN);
if (delta_fn == 1) {
ADD_MODULO(time->t2, 1, 26);
ADD_MODULO(time->t3, 1, 51);
/* if the new frame number is a multiple of 51 */
if (time->t3 == 0) {
ADD_MODULO(time->tc, 1, 8);
/* if new FN is multiple of 51 and 26 */
if (time->t2 == 0)
ADD_MODULO(time->t1, 1, 2048);
}
} else
gsm_fn2gsmtime(time, time->fn);
}
void l1s_time_dump(const struct gsm_time *time)
{
printf("fn=%lu(%u/%2u/%2u)", time->fn, time->t1, time->t2, time->t3);
}
/* clip a signed 16bit value at a certain limit */
int16_t clip_int16(int16_t angle, int16_t clip_at)
{
if (angle > clip_at)
angle = clip_at;
else if (angle < -clip_at)
angle = -clip_at;
return angle;
}
int16_t l1s_snr_int(uint16_t snr)
{
return snr >> 10;
}
uint16_t l1s_snr_fract(uint16_t snr)
{
uint32_t fract = snr & 0x3ff;
fract = fract * 1000 / (2 << 10);
return fract & 0xffff;
}
#define AFC_MAX_ANGLE 328 /* 0.01 radian in fx1.15 */
/* synchronize the L1S to a new timebase (typically a new cell */
void synchronize_tdma(struct l1_cell_info *cinfo)
{
int32_t fn_offset;
uint32_t tpu_shift = cinfo->time_alignment;
/* NB detection only works if the TOA of the SB
* is within 0...8. We have to add 75 to get an SB TOA of 4. */
tpu_shift += 75;
tpu_shift = (l1s.tpu_offset + tpu_shift) % QBITS_PER_TDMA;
fn_offset = cinfo->fn_offset - 1;
/* if we're already very close to the end of the TPU frame, the
* next interrupt will basically occur now and we need to
* compensate */
if (tpu_shift < SWITCH_TIME)
fn_offset++;
#if 0 /* probably wrong as we already added "offset" and "shift" above */
/* increment the TPU quarter-bit offset */
l1s.tpu_offset = (l1s.tpu_offset + tpu_shift) % TPU_RANGE;
#else
l1s.tpu_offset = tpu_shift;
#endif
puts("Synchronize_TDMA\n");
/* request the TPU to adjust the SYNCHRO and OFFSET registers */
tpu_enq_at(SWITCH_TIME);
tpu_enq_sync(l1s.tpu_offset);
#if 0
/* FIXME: properly end the TPU window at the emd of l1_sync() */
tpu_end_scenario();
#endif
/* Change the current time to reflect the new value */
l1s_time_inc(&l1s.current_time, fn_offset);
l1s.next_time = l1s.current_time;
l1s_time_inc(&l1s.next_time, 1);
/* The serving cell now no longer has a frame or bit offset */
cinfo->fn_offset = 0;
cinfo->time_alignment = 0;
}
void l1s_reset_hw(void)
{
dsp_api.w_page = 0;
dsp_api.r_page = 0;
dsp_api.r_page_used = 0;
dsp_api.db_w = (T_DB_MCU_TO_DSP *) BASE_API_W_PAGE_0;
dsp_api.db_r = (T_DB_DSP_TO_MCU *) BASE_API_R_PAGE_0;
dsp_api.ndb->d_dsp_page = 0;
/* we have to really reset the TPU, otherwise FB detection
* sometimes returns wrong TOA values. */
tpu_reset(1);
tpu_reset(0);
tpu_rewind();
tpu_enq_wait(5); /* really needed ? */
tpu_enq_sync(l1s.tpu_offset);
tpu_end_scenario();
}
/* Lost TDMA interrupt detection. This works by starting a hardware timer
* that is clocked by the same master clock source (VCTCXO). We expect
* 1875 timer ticks in the duration of a TDMA frame (5000 qbits / 1250 bits) */
/* Timer for detecting lost IRQ */
#define TIMER_TICKS_PER_TDMA 1875
#define TIMER_TICK_JITTER 1
static int last_timestamp;
static inline void check_lost_frame(void)
{
int diff, timestamp = hwtimer_read(1);
if (last_timestamp < timestamp)
last_timestamp += (4*TIMER_TICKS_PER_TDMA);
diff = last_timestamp - timestamp;
/* allow for a bit of jitter */
if (diff < TIMER_TICKS_PER_TDMA - TIMER_TICK_JITTER ||
diff > TIMER_TICKS_PER_TDMA + TIMER_TICK_JITTER)
printf("LOST %d!\n", diff);
last_timestamp = timestamp;
}
/* schedule a completion */
void l1s_compl_sched(enum l1_compl c)
{
unsigned long flags;
local_firq_save(flags);
l1s.scheduled_compl |= (1 << c);
local_irq_restore(flags);
}
/* main routine for synchronous part of layer 1, called by frame interrupt
* generated by TPU once every TDMA frame */
static void l1_sync(void)
{
uint16_t sched_flags;
putchart('+');
check_lost_frame();
/* Increment Time */
l1s.current_time = l1s.next_time;
l1s_time_inc(&l1s.next_time, 1);
//l1s_time_dump(&l1s.current_time); putchar(' ');
dsp_api.frame_ctr++;
dsp_api.r_page_used = 0;
/* Update pointers */
if (dsp_api.w_page == 0)
dsp_api.db_w = (T_DB_MCU_TO_DSP *) BASE_API_W_PAGE_0;
else
dsp_api.db_w = (T_DB_MCU_TO_DSP *) BASE_API_W_PAGE_1;
if (dsp_api.r_page == 0)
dsp_api.db_r = (T_DB_DSP_TO_MCU *) BASE_API_R_PAGE_0;
else
dsp_api.db_r = (T_DB_DSP_TO_MCU *) BASE_API_R_PAGE_1;
/* Reset MCU->DSP page */
dsp_api_memset((uint16_t *) dsp_api.db_w, sizeof(*dsp_api.db_w));
/* Update AFC */
afc_load_dsp();
if (dsp_api.ndb->d_error_status) {
printf("DSP Error Status: %u\n", dsp_api.ndb->d_error_status);
dsp_api.ndb->d_error_status = 0;
}
/* execute the sched_items that have been scheduled for this
* TDMA frame (including setup/cleanup steps) */
sched_flags = tdma_sched_flag_scan();
if (sched_flags & TDMA_IFLG_TPU)
l1s_win_init();
tdma_sched_execute();
if (dsp_api.r_page_used) {
/* clear and switch the read page */
dsp_api_memset((uint16_t *) dsp_api.db_r,
sizeof(*dsp_api.db_r));
/* TSM30 does it (really needed ?):
* Set crc result as "SB not found". */
dsp_api.db_r->a_sch[0] = (1<<B_SCH_CRC); /* B_SCH_CRC =1, BLUD =0 */
dsp_api.r_page ^= 1;
}
if (sched_flags & TDMA_IFLG_DSP)
dsp_end_scenario();
if (sched_flags & TDMA_IFLG_TPU)
tpu_end_scenario();
/* schedule new / upcoming TDMA items */
mframe_schedule();
/* schedule new / upcoming one-shot events */
sched_gsmtime_execute(l1s.current_time.fn);
tdma_sched_advance();
}
/* ABORT command ********************************************************/
static int l1s_abort_cmd(__unused uint8_t p1, __unused uint8_t p2,
__unused uint16_t p3)
{
putchart('A');
/* similar to l1s_reset_hw() without touching the TPU */
dsp_api.w_page = 0;
dsp_api.r_page = 0;
dsp_api.r_page_used = 0;
dsp_api.db_w = (T_DB_MCU_TO_DSP *) BASE_API_W_PAGE_0;
dsp_api.db_r = (T_DB_DSP_TO_MCU *) BASE_API_R_PAGE_0;
/* Reset task commands. */
dsp_api.db_w->d_task_d = NO_DSP_TASK; /* Init. RX task to NO TASK */
dsp_api.db_w->d_task_u = NO_DSP_TASK; /* Init. TX task to NO TASK */
dsp_api.db_w->d_task_ra = NO_DSP_TASK; /* Init. RA task to NO TASK */
dsp_api.db_w->d_task_md = NO_DSP_TASK; /* Init. MONITORING task to NO TASK */
dsp_api.ndb->d_dsp_page = 0;
/* Set "b_abort" to TRUE, dsp will reset current and pending tasks */
dsp_api.db_w->d_ctrl_system |= (1 << B_TASK_ABORT);
return 0;
}
void l1s_dsp_abort(void)
{
/* abort right now */
tdma_schedule(0, &l1s_abort_cmd, 0, 0, 0, 10);
}
void l1s_tx_apc_helper(uint16_t arfcn)
{
int16_t auxapc;
enum gsm_band band;
int i;
/* Get DAC setting */
band = gsm_arfcn2band(arfcn);
auxapc = apc_tx_pwrlvl2auxapc(band, l1s.tx_power);
/* Load the ApcOffset into the DSP */
#define MY_OFFSET 4
dsp_api.ndb->d_apcoff = ABB_VAL(APCOFF, (1 << 6) | MY_OFFSET) | 1; /* 2x slope for the GTA-02 ramp */
/* Load the TX Power into the DSP */
/*
If the power is too low (below 0 dBm) the ramp is not OK,
especially for GSM-1800. However an MS does not send below
0dBm anyway.
*/
dsp_api.db_w->d_power_ctl = ABB_VAL(AUXAPC, auxapc);
/* Update the ramp according to the PCL */
for (i = 0; i < 16; i++)
dsp_api.ndb->a_ramp[i] = ABB_VAL(APCRAM, twl3025_default_ramp[i]);
/* The Ramp Table is sent to ABB only once after RF init routine called */
dsp_api.db_w->d_ctrl_abb |= (1 << B_RAMP) | (1 << B_BULRAMPDEL);
}
/* Interrupt handler */
static void frame_irq(__unused enum irq_nr nr)
{
l1_sync();
}
/* reset the layer1 as part of synchronizing to a new cell */
void l1s_reset(void)
{
/* Reset state */
l1s.fb.mode = 0;
l1s.tx_power = 7; /* initial power reset */
/* Leave dedicated mode */
l1s.dedicated.type = GSM_DCHAN_NONE;
/* reset scheduler and hardware */
sched_gsmtime_reset();
mframe_reset();
tdma_sched_reset();
l1s_dsp_abort();
/* Cipher off */
dsp_load_ciph_param(0, NULL);
}
void l1s_init(void)
{
unsigned int i;
for (i = 0; i < ARRAY_SIZE(l1s.tx_queue); i++)
INIT_LLIST_HEAD(&l1s.tx_queue[i]);
l1s.tx_meas = NULL;
sched_gsmtime_init();
/* register FRAME interrupt as FIQ so it can interrupt normal IRQs */
irq_register_handler(IRQ_TPU_FRAME, &frame_irq);
irq_config(IRQ_TPU_FRAME, 1, 1, 0);
irq_enable(IRQ_TPU_FRAME);
/* configure timer 1 to be auto-reload and have a prescale of 12 (13MHz/12 == qbit clock) */
hwtimer_enable(1, 1);
hwtimer_load(1, (1875*4)-1);
hwtimer_config(1, 0, 1);
hwtimer_enable(1, 1);
}
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