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linux/sound/isa/sb/sb8_midi.c
Takashi Iwai 20e5f8bfb1 ALSA: sb: Minor optimization / fix of timer usage in sb8_midi.c 
Currently the SB8 MIDI code sets up the timer object at each time
before scheduling it at trigger callback, but basically this is
superfluous once after set up.  Also, the code misses the
del_timer_sync() call that may leave a race condition for
use-after-free.

This patch addresses these issues, moving timer_setup() to
snd_sb8dsp_midi(), and adding the del_timer_sync() call at
snd_sb8dsp_midi_output_trigger() to make sure.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-10-25 10:00:43 +02:00

280 lines
8.1 KiB
C
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/*
* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
* Routines for control of SoundBlaster cards - MIDI interface
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* --
*
* Sun May 9 22:54:38 BST 1999 George David Morrison <gdm@gedamo.demon.co.uk>
* Fixed typo in snd_sb8dsp_midi_new_device which prevented midi from
* working.
*
* Sun May 11 12:34:56 UTC 2003 Clemens Ladisch <clemens@ladisch.de>
* Added full duplex UART mode for DSP version 2.0 and later.
*/
#include <linux/io.h>
#include <linux/time.h>
#include <sound/core.h>
#include <sound/sb.h>
irqreturn_t snd_sb8dsp_midi_interrupt(struct snd_sb *chip)
{
struct snd_rawmidi *rmidi;
int max = 64;
char byte;
if (!chip)
return IRQ_NONE;
rmidi = chip->rmidi;
if (!rmidi) {
inb(SBP(chip, DATA_AVAIL)); /* ack interrupt */
return IRQ_NONE;
}
spin_lock(&chip->midi_input_lock);
while (max-- > 0) {
if (inb(SBP(chip, DATA_AVAIL)) & 0x80) {
byte = inb(SBP(chip, READ));
if (chip->open & SB_OPEN_MIDI_INPUT_TRIGGER) {
snd_rawmidi_receive(chip->midi_substream_input, &byte, 1);
}
}
}
spin_unlock(&chip->midi_input_lock);
return IRQ_HANDLED;
}
static int snd_sb8dsp_midi_input_open(struct snd_rawmidi_substream *substream)
{
unsigned long flags;
struct snd_sb *chip;
unsigned int valid_open_flags;
chip = substream->rmidi->private_data;
valid_open_flags = chip->hardware >= SB_HW_20
? SB_OPEN_MIDI_OUTPUT | SB_OPEN_MIDI_OUTPUT_TRIGGER : 0;
spin_lock_irqsave(&chip->open_lock, flags);
if (chip->open & ~valid_open_flags) {
spin_unlock_irqrestore(&chip->open_lock, flags);
return -EAGAIN;
}
chip->open |= SB_OPEN_MIDI_INPUT;
chip->midi_substream_input = substream;
if (!(chip->open & SB_OPEN_MIDI_OUTPUT)) {
spin_unlock_irqrestore(&chip->open_lock, flags);
snd_sbdsp_reset(chip); /* reset DSP */
if (chip->hardware >= SB_HW_20)
snd_sbdsp_command(chip, SB_DSP_MIDI_UART_IRQ);
} else {
spin_unlock_irqrestore(&chip->open_lock, flags);
}
return 0;
}
static int snd_sb8dsp_midi_output_open(struct snd_rawmidi_substream *substream)
{
unsigned long flags;
struct snd_sb *chip;
unsigned int valid_open_flags;
chip = substream->rmidi->private_data;
valid_open_flags = chip->hardware >= SB_HW_20
? SB_OPEN_MIDI_INPUT | SB_OPEN_MIDI_INPUT_TRIGGER : 0;
spin_lock_irqsave(&chip->open_lock, flags);
if (chip->open & ~valid_open_flags) {
spin_unlock_irqrestore(&chip->open_lock, flags);
return -EAGAIN;
}
chip->open |= SB_OPEN_MIDI_OUTPUT;
chip->midi_substream_output = substream;
if (!(chip->open & SB_OPEN_MIDI_INPUT)) {
spin_unlock_irqrestore(&chip->open_lock, flags);
snd_sbdsp_reset(chip); /* reset DSP */
if (chip->hardware >= SB_HW_20)
snd_sbdsp_command(chip, SB_DSP_MIDI_UART_IRQ);
} else {
spin_unlock_irqrestore(&chip->open_lock, flags);
}
return 0;
}
static int snd_sb8dsp_midi_input_close(struct snd_rawmidi_substream *substream)
{
unsigned long flags;
struct snd_sb *chip;
chip = substream->rmidi->private_data;
spin_lock_irqsave(&chip->open_lock, flags);
chip->open &= ~(SB_OPEN_MIDI_INPUT | SB_OPEN_MIDI_INPUT_TRIGGER);
chip->midi_substream_input = NULL;
if (!(chip->open & SB_OPEN_MIDI_OUTPUT)) {
spin_unlock_irqrestore(&chip->open_lock, flags);
snd_sbdsp_reset(chip); /* reset DSP */
} else {
spin_unlock_irqrestore(&chip->open_lock, flags);
}
return 0;
}
static int snd_sb8dsp_midi_output_close(struct snd_rawmidi_substream *substream)
{
unsigned long flags;
struct snd_sb *chip;
chip = substream->rmidi->private_data;
del_timer_sync(&chip->midi_timer);
spin_lock_irqsave(&chip->open_lock, flags);
chip->open &= ~(SB_OPEN_MIDI_OUTPUT | SB_OPEN_MIDI_OUTPUT_TRIGGER);
chip->midi_substream_output = NULL;
if (!(chip->open & SB_OPEN_MIDI_INPUT)) {
spin_unlock_irqrestore(&chip->open_lock, flags);
snd_sbdsp_reset(chip); /* reset DSP */
} else {
spin_unlock_irqrestore(&chip->open_lock, flags);
}
return 0;
}
static void snd_sb8dsp_midi_input_trigger(struct snd_rawmidi_substream *substream, int up)
{
unsigned long flags;
struct snd_sb *chip;
chip = substream->rmidi->private_data;
spin_lock_irqsave(&chip->open_lock, flags);
if (up) {
if (!(chip->open & SB_OPEN_MIDI_INPUT_TRIGGER)) {
if (chip->hardware < SB_HW_20)
snd_sbdsp_command(chip, SB_DSP_MIDI_INPUT_IRQ);
chip->open |= SB_OPEN_MIDI_INPUT_TRIGGER;
}
} else {
if (chip->open & SB_OPEN_MIDI_INPUT_TRIGGER) {
if (chip->hardware < SB_HW_20)
snd_sbdsp_command(chip, SB_DSP_MIDI_INPUT_IRQ);
chip->open &= ~SB_OPEN_MIDI_INPUT_TRIGGER;
}
}
spin_unlock_irqrestore(&chip->open_lock, flags);
}
static void snd_sb8dsp_midi_output_write(struct snd_rawmidi_substream *substream)
{
unsigned long flags;
struct snd_sb *chip;
char byte;
int max = 32;
/* how big is Tx FIFO? */
chip = substream->rmidi->private_data;
while (max-- > 0) {
spin_lock_irqsave(&chip->open_lock, flags);
if (snd_rawmidi_transmit_peek(substream, &byte, 1) != 1) {
chip->open &= ~SB_OPEN_MIDI_OUTPUT_TRIGGER;
del_timer(&chip->midi_timer);
spin_unlock_irqrestore(&chip->open_lock, flags);
break;
}
if (chip->hardware >= SB_HW_20) {
int timeout = 8;
while ((inb(SBP(chip, STATUS)) & 0x80) != 0 && --timeout > 0)
;
if (timeout == 0) {
/* Tx FIFO full - try again later */
spin_unlock_irqrestore(&chip->open_lock, flags);
break;
}
outb(byte, SBP(chip, WRITE));
} else {
snd_sbdsp_command(chip, SB_DSP_MIDI_OUTPUT);
snd_sbdsp_command(chip, byte);
}
snd_rawmidi_transmit_ack(substream, 1);
spin_unlock_irqrestore(&chip->open_lock, flags);
}
}
static void snd_sb8dsp_midi_output_timer(struct timer_list *t)
{
struct snd_sb *chip = from_timer(chip, t, midi_timer);
struct snd_rawmidi_substream *substream = chip->midi_substream_output;
unsigned long flags;
spin_lock_irqsave(&chip->open_lock, flags);
mod_timer(&chip->midi_timer, 1 + jiffies);
spin_unlock_irqrestore(&chip->open_lock, flags);
snd_sb8dsp_midi_output_write(substream);
}
static void snd_sb8dsp_midi_output_trigger(struct snd_rawmidi_substream *substream, int up)
{
unsigned long flags;
struct snd_sb *chip;
chip = substream->rmidi->private_data;
spin_lock_irqsave(&chip->open_lock, flags);
if (up) {
if (!(chip->open & SB_OPEN_MIDI_OUTPUT_TRIGGER)) {
mod_timer(&chip->midi_timer, 1 + jiffies);
chip->open |= SB_OPEN_MIDI_OUTPUT_TRIGGER;
}
} else {
if (chip->open & SB_OPEN_MIDI_OUTPUT_TRIGGER) {
chip->open &= ~SB_OPEN_MIDI_OUTPUT_TRIGGER;
}
}
spin_unlock_irqrestore(&chip->open_lock, flags);
if (up)
snd_sb8dsp_midi_output_write(substream);
}
static const struct snd_rawmidi_ops snd_sb8dsp_midi_output =
{
.open = snd_sb8dsp_midi_output_open,
.close = snd_sb8dsp_midi_output_close,
.trigger = snd_sb8dsp_midi_output_trigger,
};
static const struct snd_rawmidi_ops snd_sb8dsp_midi_input =
{
.open = snd_sb8dsp_midi_input_open,
.close = snd_sb8dsp_midi_input_close,
.trigger = snd_sb8dsp_midi_input_trigger,
};
int snd_sb8dsp_midi(struct snd_sb *chip, int device)
{
struct snd_rawmidi *rmidi;
int err;
if ((err = snd_rawmidi_new(chip->card, "SB8 MIDI", device, 1, 1, &rmidi)) < 0)
return err;
strcpy(rmidi->name, "SB8 MIDI");
snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &snd_sb8dsp_midi_output);
snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &snd_sb8dsp_midi_input);
rmidi->info_flags |= SNDRV_RAWMIDI_INFO_OUTPUT | SNDRV_RAWMIDI_INFO_INPUT;
if (chip->hardware >= SB_HW_20)
rmidi->info_flags |= SNDRV_RAWMIDI_INFO_DUPLEX;
rmidi->private_data = chip;
timer_setup(&chip->midi_timer, snd_sb8dsp_midi_output_timer, 0);
chip->rmidi = rmidi;
return 0;
}
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