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08fdced60c
This commit adds a new framing mode that frames all MIDI data into 32-byte frames with a timestamp. The main benefit is that we can get accurate timestamps even if userspace wakeup and processing is not immediate. Testing on a Celeron N3150 with this mode has a max jitter of 2.8 ms, compared to the in-kernel seq implementation which has a max jitter of 5 ms during idle and much worse when running scheduler stress tests in parallel. Signed-off-by: David Henningsson <coding@diwic.se> Reviewed-by: Jaroslav Kysela <perex@perex.cz> Link: https://lore.kernel.org/r/20210515071533.55332-1-coding@diwic.se Signed-off-by: Takashi Iwai <tiwai@suse.de>
124 lines
3.3 KiB
C
124 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* 32bit -> 64bit ioctl wrapper for raw MIDI API
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* Copyright (c) by Takashi Iwai <tiwai@suse.de>
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*/
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/* This file included from rawmidi.c */
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#include <linux/compat.h>
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struct snd_rawmidi_params32 {
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s32 stream;
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u32 buffer_size;
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u32 avail_min;
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unsigned int no_active_sensing; /* avoid bit-field */
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unsigned int mode;
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unsigned char reserved[12];
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} __attribute__((packed));
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static int snd_rawmidi_ioctl_params_compat(struct snd_rawmidi_file *rfile,
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struct snd_rawmidi_params32 __user *src)
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{
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struct snd_rawmidi_params params;
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unsigned int val;
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if (get_user(params.stream, &src->stream) ||
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get_user(params.buffer_size, &src->buffer_size) ||
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get_user(params.avail_min, &src->avail_min) ||
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get_user(params.mode, &src->mode) ||
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get_user(val, &src->no_active_sensing))
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return -EFAULT;
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params.no_active_sensing = val;
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switch (params.stream) {
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case SNDRV_RAWMIDI_STREAM_OUTPUT:
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if (!rfile->output)
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return -EINVAL;
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return snd_rawmidi_output_params(rfile->output, ¶ms);
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case SNDRV_RAWMIDI_STREAM_INPUT:
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if (!rfile->input)
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return -EINVAL;
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return snd_rawmidi_input_params(rfile->input, ¶ms);
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}
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return -EINVAL;
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}
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struct compat_snd_rawmidi_status64 {
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s32 stream;
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u8 rsvd[4]; /* alignment */
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s64 tstamp_sec;
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s64 tstamp_nsec;
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u32 avail;
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u32 xruns;
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unsigned char reserved[16];
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} __attribute__((packed));
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static int snd_rawmidi_ioctl_status_compat64(struct snd_rawmidi_file *rfile,
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struct compat_snd_rawmidi_status64 __user *src)
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{
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int err;
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struct snd_rawmidi_status64 status;
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struct compat_snd_rawmidi_status64 compat_status;
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if (get_user(status.stream, &src->stream))
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return -EFAULT;
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switch (status.stream) {
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case SNDRV_RAWMIDI_STREAM_OUTPUT:
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if (!rfile->output)
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return -EINVAL;
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err = snd_rawmidi_output_status(rfile->output, &status);
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break;
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case SNDRV_RAWMIDI_STREAM_INPUT:
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if (!rfile->input)
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return -EINVAL;
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err = snd_rawmidi_input_status(rfile->input, &status);
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break;
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default:
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return -EINVAL;
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}
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if (err < 0)
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return err;
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compat_status = (struct compat_snd_rawmidi_status64) {
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.stream = status.stream,
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.tstamp_sec = status.tstamp_sec,
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.tstamp_nsec = status.tstamp_nsec,
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.avail = status.avail,
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.xruns = status.xruns,
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};
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if (copy_to_user(src, &compat_status, sizeof(*src)))
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return -EFAULT;
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return 0;
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}
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enum {
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SNDRV_RAWMIDI_IOCTL_PARAMS32 = _IOWR('W', 0x10, struct snd_rawmidi_params32),
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SNDRV_RAWMIDI_IOCTL_STATUS_COMPAT32 = _IOWR('W', 0x20, struct snd_rawmidi_status32),
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SNDRV_RAWMIDI_IOCTL_STATUS_COMPAT64 = _IOWR('W', 0x20, struct compat_snd_rawmidi_status64),
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};
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static long snd_rawmidi_ioctl_compat(struct file *file, unsigned int cmd, unsigned long arg)
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{
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struct snd_rawmidi_file *rfile;
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void __user *argp = compat_ptr(arg);
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rfile = file->private_data;
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switch (cmd) {
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case SNDRV_RAWMIDI_IOCTL_PVERSION:
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case SNDRV_RAWMIDI_IOCTL_INFO:
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case SNDRV_RAWMIDI_IOCTL_DROP:
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case SNDRV_RAWMIDI_IOCTL_DRAIN:
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return snd_rawmidi_ioctl(file, cmd, (unsigned long)argp);
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case SNDRV_RAWMIDI_IOCTL_PARAMS32:
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return snd_rawmidi_ioctl_params_compat(rfile, argp);
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case SNDRV_RAWMIDI_IOCTL_STATUS_COMPAT32:
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return snd_rawmidi_ioctl_status32(rfile, argp);
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case SNDRV_RAWMIDI_IOCTL_STATUS_COMPAT64:
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return snd_rawmidi_ioctl_status_compat64(rfile, argp);
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}
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return -ENOIOCTLCMD;
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}
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