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/*
* Copyright © 2015 Keith Packard <keithp@keithp.com>
*
* 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; version 2 of the License.
*
* 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 _AO_ADC_FAST_H_
#define _AO_ADC_FAST_H_
void
ao_adc_read(uint16_t *dest, int len);
void
ao_adc_init(void);
/* Total ring size in samples */
#define AO_ADC_RING_SIZE 256
/* Number of samples fetched per ao_adc_start call */
#define AO_ADC_RING_CHUNK (AO_ADC_RING_SIZE >> 1)
extern uint16_t ao_adc_ring[AO_ADC_RING_SIZE];
#define ao_adc_ring_step(pos,inc) (((pos) + (inc)) & (AO_ADC_RING_SIZE - 1))
extern uint16_t ao_adc_ring_head, ao_adc_ring_tail;
extern uint8_t ao_adc_running;
void
_ao_adc_start(void);
static inline uint16_t
_ao_adc_remain(void)
{
if (ao_adc_ring_tail > ao_adc_ring_head)
return AO_ADC_RING_SIZE - ao_adc_ring_tail;
return ao_adc_ring_head - ao_adc_ring_tail;
}
static inline uint16_t
_ao_adc_space(void)
{
if (ao_adc_ring_head == ao_adc_ring_tail)
return AO_ADC_RING_SIZE;
if (ao_adc_ring_head > ao_adc_ring_tail)
return AO_ADC_RING_SIZE - ao_adc_ring_head;
return ao_adc_ring_tail - ao_adc_ring_head;
}
static inline uint16_t *
ao_adc_get(uint16_t n)
{
if (ao_adc_ring_tail + n > AO_ADC_RING_SIZE)
ao_panic(AO_PANIC_ADC);
ao_arch_block_interrupts();
while (_ao_adc_remain() < n) {
if (!ao_adc_running)
_ao_adc_start();
ao_sleep(&ao_adc_ring_head);
}
ao_arch_release_interrupts();
return &ao_adc_ring[ao_adc_ring_tail];
}
static inline void
ao_adc_ack(uint16_t n)
{
if (ao_adc_ring_tail + n > AO_ADC_RING_SIZE)
ao_panic(AO_PANIC_ADC);
ao_arch_block_interrupts();
ao_adc_ring_tail += n;
if (ao_adc_ring_tail == AO_ADC_RING_SIZE)
ao_adc_ring_tail = 0;
if (!ao_adc_running && _ao_adc_space() >= AO_ADC_RING_CHUNK)
_ao_adc_start();
ao_arch_release_interrupts();
}
#endif /* _AO_ADC_FAST_H_ */
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