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Pisound: MIDI communication fixes for scaled down CPU.

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* Increased maximum SPI communication speed to avoid running too slow
  when the CPU is scaled down and losing MIDI data.

* Keep track of buffer usage in millibytes for higher precision.

Signed-off-by: Giedrius Trainavičius <giedrius@blokas.io>
This commit is contained in:
Giedrius
2020-01-07 11:04:21 +02:00
committed by popcornmix
parent 76f2adafd6
commit d10c7d7946
1 changed files with 18 additions and 13 deletions
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31
sound/soc/bcm/pisound.c
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@@ -1,6 +1,6 @@
/*
* Pisound Linux kernel module.
* Copyright (C) 2016-2019 Vilniaus Blokas UAB, https://blokas.io/pisound
* Copyright (C) 2016-2020 Vilniaus Blokas UAB, https://blokas.io/pisound
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
@@ -326,7 +326,7 @@ static void spi_transfer(const uint8_t *txbuf, uint8_t *rxbuf, int len)
transfer.tx_buf = txbuf;
transfer.rx_buf = rxbuf;
transfer.len = len;
transfer.speed_hz = 100000;
transfer.speed_hz = 150000;
transfer.delay_usecs = 10;
spi_message_add_tail(&transfer, &msg);
@@ -403,9 +403,9 @@ static struct spi_device *pisnd_spi_find_device(void)
static void pisnd_work_handler(struct work_struct *work)
{
enum { TRANSFER_SIZE = 4 };
enum { PISOUND_OUTPUT_BUFFER_SIZE = 128 };
enum { MIDI_BYTES_PER_SECOND = 3125 };
int out_buffer_used = 0;
enum { PISOUND_OUTPUT_BUFFER_SIZE_MILLIBYTES = 127 * 1000 };
enum { MIDI_MILLIBYTES_PER_JIFFIE = (3125 * 1000) / HZ };
int out_buffer_used_millibytes = 0;
unsigned long now;
uint8_t val;
uint8_t txbuf[TRANSFER_SIZE];
@@ -445,7 +445,9 @@ static void pisnd_work_handler(struct work_struct *work)
had_data = false;
memset(txbuf, 0, sizeof(txbuf));
for (i = 0; i < sizeof(txbuf) &&
out_buffer_used < PISOUND_OUTPUT_BUFFER_SIZE;
((out_buffer_used_millibytes+1000 <
PISOUND_OUTPUT_BUFFER_SIZE_MILLIBYTES) ||
g_ledFlashDurationChanged);
i += 2) {
val = 0;
@@ -458,7 +460,7 @@ static void pisnd_work_handler(struct work_struct *work)
} else if (kfifo_get(&spi_fifo_out, &val)) {
txbuf[i+0] = 0x0f;
txbuf[i+1] = val;
++out_buffer_used;
out_buffer_used_millibytes += 1000;
}
}
@@ -469,12 +471,14 @@ static void pisnd_work_handler(struct work_struct *work)
* rate.
*/
now = jiffies;
out_buffer_used -=
(MIDI_BYTES_PER_SECOND / HZ) /
(now - last_transfer_at);
if (out_buffer_used < 0)
out_buffer_used = 0;
last_transfer_at = now;
if (now != last_transfer_at) {
out_buffer_used_millibytes -=
(now - last_transfer_at) *
MIDI_MILLIBYTES_PER_JIFFIE;
if (out_buffer_used_millibytes < 0)
out_buffer_used_millibytes = 0;
last_transfer_at = now;
}
for (i = 0; i < sizeof(rxbuf); i += 2) {
if (rxbuf[i]) {
@@ -489,6 +493,7 @@ static void pisnd_work_handler(struct work_struct *work)
|| !kfifo_is_empty(&spi_fifo_out)
|| pisnd_spi_has_more()
|| g_ledFlashDurationChanged
|| out_buffer_used_millibytes != 0
);
if (!kfifo_is_empty(&spi_fifo_in) && g_recvCallback)