// SPDX-License-Identifier: GPL-2.0-only
/*
 * Line 6 Linux USB driver
 *
 * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
 */

#include <linux/slab.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>

#include "capture.h"
#include "driver.h"
#include "pcm.h"
#include "playback.h"

/*
        Software stereo volume control.
*/
static void change_volume(struct urb *urb_out, int volume[],
                          int bytes_per_frame)
{
        int chn = 0;

        if (volume[0] == 256 && volume[1] == 256)
                return;         /* maximum volume - no change */

        if (bytes_per_frame == 4) {
                __le16 *p, *buf_end;

                p = (__le16 *)urb_out->transfer_buffer;
                buf_end = p + urb_out->transfer_buffer_length / sizeof(*p);

                for (; p < buf_end; ++p) {
                        short pv = le16_to_cpu(*p);
                        int val = (pv * volume[chn & 1]) >> 8;
                        pv = clamp(val, -0x8000, 0x7fff);
                        *p = cpu_to_le16(pv);
                        ++chn;
                }
        } else if (bytes_per_frame == 6) {
                unsigned char *p, *buf_end;

                p = (unsigned char *)urb_out->transfer_buffer;
                buf_end = p + urb_out->transfer_buffer_length;

                for (; p < buf_end; p += 3) {
                        int val;

                        val = p[0] + (p[1] << 8) + ((signed char)p[2] << 16);
                        val = (val * volume[chn & 1]) >> 8;
                        val = clamp(val, -0x800000, 0x7fffff);
                        p[0] = val;
                        p[1] = val >> 8;
                        p[2] = val >> 16;
                        ++chn;
                }
        }
}

/*
        Create signal for impulse response test.
*/
static void create_impulse_test_signal(struct snd_line6_pcm *line6pcm,
                                       struct urb *urb_out, int bytes_per_frame)
{
        int frames = urb_out->transfer_buffer_length / bytes_per_frame;

        if (bytes_per_frame == 4) {
                int i;
                short *pi = (short *)line6pcm->prev_fbuf;
                short *po = (short *)urb_out->transfer_buffer;

                for (i = 0; i < frames; ++i) {
                        po[0] = pi[0];
                        po[1] = 0;
                        pi += 2;
                        po += 2;
                }
        } else if (bytes_per_frame == 6) {
                int i, j;
                unsigned char *pi = line6pcm->prev_fbuf;
                unsigned char *po = urb_out->transfer_buffer;

                for (i = 0; i < frames; ++i) {
                        for (j = 0; j < bytes_per_frame / 2; ++j)
                                po[j] = pi[j];

                        for (; j < bytes_per_frame; ++j)
                                po[j] = 0;

                        pi += bytes_per_frame;
                        po += bytes_per_frame;
                }
        }
        if (--line6pcm->impulse_count <= 0) {
                ((unsigned char *)(urb_out->transfer_buffer))[bytes_per_frame -
                                                              1] =
                    line6pcm->impulse_volume;
                line6pcm->impulse_count = line6pcm->impulse_period;
        }
}

/*
        Add signal to buffer for software monitoring.
*/
static void add_monitor_signal(struct urb *urb_out, unsigned char *signal,
                               int volume, int bytes_per_frame)
{
        if (volume == 0)
                return;         /* zero volume - no change */

        if (bytes_per_frame == 4) {
                __le16 *pi, *po, *buf_end;

                pi = (__le16 *)signal;
                po = (__le16 *)urb_out->transfer_buffer;
                buf_end = po + urb_out->transfer_buffer_length / sizeof(*po);

                for (; po < buf_end; ++pi, ++po) {
                        short pov = le16_to_cpu(*po);
                        short piv = le16_to_cpu(*pi);
                        int val = pov + ((piv * volume) >> 8);
                        pov = clamp(val, -0x8000, 0x7fff);
                        *po = cpu_to_le16(pov);
                }
        }

        /*
           We don't need to handle devices with 6 bytes per frame here
           since they all support hardware monitoring.
         */
}

/*
        Find a free URB, prepare audio data, and submit URB.
        must be called in line6pcm->out.lock context
*/
static int submit_audio_out_urb(struct snd_line6_pcm *line6pcm)
{
        int index;
        int i, urb_size, urb_frames;
        int ret;
        const int bytes_per_frame =
                line6pcm->properties->bytes_per_channel *
                line6pcm->properties->playback_hw.channels_max;
        const int frame_increment =
                line6pcm->properties->rates.rats[0].num_min;
        const int frame_factor =
                line6pcm->properties->rates.rats[0].den *
                (line6pcm->line6->intervals_per_second / LINE6_ISO_INTERVAL);
        struct urb *urb_out;

        index = find_first_zero_bit(&line6pcm->out.active_urbs,
                                    line6pcm->line6->iso_buffers);

        if (index < 0 || index >= line6pcm->line6->iso_buffers) {
                dev_err(line6pcm->line6->ifcdev, "no free URB found\n");
                return -EINVAL;
        }

        urb_out = line6pcm->out.urbs[index];
        urb_size = 0;

        /* TODO: this may not work for LINE6_ISO_PACKETS != 1 */
        for (i = 0; i < LINE6_ISO_PACKETS; ++i) {
                /* compute frame size for given sampling rate */
                int fsize = 0;
                struct usb_iso_packet_descriptor *fout =
                    &urb_out->iso_frame_desc[i];

                fsize = line6pcm->prev_fsize;
                if (fsize == 0) {
                        int n;

                        line6pcm->out.count += frame_increment;
                        n = line6pcm->out.count / frame_factor;
                        line6pcm->out.count -= n * frame_factor;
                        fsize = n;
                }

                fsize *= bytes_per_frame;

                fout->offset = urb_size;
                fout->length = fsize;
                urb_size += fsize;
        }

        if (urb_size == 0) {
                /* can't determine URB size */
                dev_err(line6pcm->line6->ifcdev, "driver bug: urb_size = 0\n");
                return -EINVAL;
        }

        urb_frames = urb_size / bytes_per_frame;
        urb_out->transfer_buffer =
            line6pcm->out.buffer +
            index * LINE6_ISO_PACKETS * line6pcm->max_packet_size_out;
        urb_out->transfer_buffer_length = urb_size;
        urb_out->context = line6pcm;

        if (test_bit(LINE6_STREAM_PCM, &line6pcm->out.running) &&
            !test_bit(LINE6_FLAG_PAUSE_PLAYBACK, &line6pcm->flags)) {
                struct snd_pcm_runtime *runtime =
                    get_substream(line6pcm, SNDRV_PCM_STREAM_PLAYBACK)->runtime;

                if (line6pcm->out.pos + urb_frames > runtime->buffer_size) {
                        /*
                           The transferred area goes over buffer boundary,
                           copy the data to the temp buffer.
                         */
                        int len;

                        len = runtime->buffer_size - line6pcm->out.pos;

                        if (len > 0) {
                                memcpy(urb_out->transfer_buffer,
                                       runtime->dma_area +
                                       line6pcm->out.pos * bytes_per_frame,
                                       len * bytes_per_frame);
                                memcpy(urb_out->transfer_buffer +
                                       len * bytes_per_frame, runtime->dma_area,
                                       (urb_frames - len) * bytes_per_frame);
                        } else
                                dev_err(line6pcm->line6->ifcdev, "driver bug: len = %d\n",
                                        len);
                } else {
                        memcpy(urb_out->transfer_buffer,
                               runtime->dma_area +
                               line6pcm->out.pos * bytes_per_frame,
                               urb_out->transfer_buffer_length);
                }

                line6pcm->out.pos += urb_frames;
                if (line6pcm->out.pos >= runtime->buffer_size)
                        line6pcm->out.pos -= runtime->buffer_size;

                change_volume(urb_out, line6pcm->volume_playback,
                              bytes_per_frame);
        } else {
                memset(urb_out->transfer_buffer, 0,
                       urb_out->transfer_buffer_length);
        }

        spin_lock_nested(&line6pcm->in.lock, SINGLE_DEPTH_NESTING);
        if (line6pcm->prev_fbuf) {
                if (test_bit(LINE6_STREAM_IMPULSE, &line6pcm->out.running)) {
                        create_impulse_test_signal(line6pcm, urb_out,
                                                   bytes_per_frame);
                        if (test_bit(LINE6_STREAM_PCM, &line6pcm->in.running)) {
                                line6_capture_copy(line6pcm,
                                                   urb_out->transfer_buffer,
                                                   urb_out->
                                                   transfer_buffer_length);
                                line6_capture_check_period(line6pcm,
                                        urb_out->transfer_buffer_length);
                        }
                } else {
                        if (!(line6pcm->line6->properties->capabilities & LINE6_CAP_HWMON)
                            && line6pcm->out.running && line6pcm->in.running)
                                add_monitor_signal(urb_out, line6pcm->prev_fbuf,
                                                   line6pcm->volume_monitor,
                                                   bytes_per_frame);
                }
                line6pcm->prev_fbuf = NULL;
                line6pcm->prev_fsize = 0;
        }
        spin_unlock(&line6pcm->in.lock);

        ret = usb_submit_urb(urb_out, GFP_ATOMIC);

        if (ret == 0)
                set_bit(index, &line6pcm->out.active_urbs);
        else
                dev_err(line6pcm->line6->ifcdev,
                        "URB out #%d submission failed (%d)\n", index, ret);

        return 0;
}

/*
        Submit all currently available playback URBs.
        must be called in line6pcm->out.lock context
 */
int line6_submit_audio_out_all_urbs(struct snd_line6_pcm *line6pcm)
{
        int ret = 0, i;

        for (i = 0; i < line6pcm->line6->iso_buffers; ++i) {
                ret = submit_audio_out_urb(line6pcm);
                if (ret < 0)
                        break;
        }

        return ret;
}

/*
        Callback for completed playback URB.
*/
static void audio_out_callback(struct urb *urb)
{
        int i, index, length = 0, shutdown = 0;
        unsigned long flags;
        struct snd_line6_pcm *line6pcm = (struct snd_line6_pcm *)urb->context;
        struct snd_pcm_substream *substream =
            get_substream(line6pcm, SNDRV_PCM_STREAM_PLAYBACK);
        const int bytes_per_frame =
                line6pcm->properties->bytes_per_channel *
                line6pcm->properties->playback_hw.channels_max;

#if USE_CLEAR_BUFFER_WORKAROUND
        memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);
#endif

        line6pcm->out.last_frame = urb->start_frame;

        /* find index of URB */
        for (index = 0; index < line6pcm->line6->iso_buffers; index++)
                if (urb == line6pcm->out.urbs[index])
                        break;

        if (index >= line6pcm->line6->iso_buffers)
                return;         /* URB has been unlinked asynchronously */

        for (i = 0; i < LINE6_ISO_PACKETS; i++)
                length += urb->iso_frame_desc[i].length;

        spin_lock_irqsave(&line6pcm->out.lock, flags);

        if (test_bit(LINE6_STREAM_PCM, &line6pcm->out.running)) {
                struct snd_pcm_runtime *runtime = substream->runtime;

                line6pcm->out.pos_done +=
                    length / bytes_per_frame;

                if (line6pcm->out.pos_done >= runtime->buffer_size)
                        line6pcm->out.pos_done -= runtime->buffer_size;
        }

        clear_bit(index, &line6pcm->out.active_urbs);

        for (i = 0; i < LINE6_ISO_PACKETS; i++)
                if (urb->iso_frame_desc[i].status == -EXDEV) {
                        shutdown = 1;
                        break;
                }

        if (test_and_clear_bit(index, &line6pcm->out.unlink_urbs))
                shutdown = 1;

        if (!shutdown) {
                submit_audio_out_urb(line6pcm);

                if (test_bit(LINE6_STREAM_PCM, &line6pcm->out.running)) {
                        line6pcm->out.bytes += length;
                        if (line6pcm->out.bytes >= line6pcm->out.period) {
                                line6pcm->out.bytes %= line6pcm->out.period;
                                spin_unlock(&line6pcm->out.lock);
                                snd_pcm_period_elapsed(substream);
                                spin_lock(&line6pcm->out.lock);
                        }
                }
        }
        spin_unlock_irqrestore(&line6pcm->out.lock, flags);
}

/* open playback callback */
static int snd_line6_playback_open(struct snd_pcm_substream *substream)
{
        int err;
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct snd_line6_pcm *line6pcm = snd_pcm_substream_chip(substream);

        err = snd_pcm_hw_constraint_ratdens(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
                                            &line6pcm->properties->rates);
        if (err < 0)
                return err;

        runtime->hw = line6pcm->properties->playback_hw;
        return 0;
}

/* close playback callback */
static int snd_line6_playback_close(struct snd_pcm_substream *substream)
{
        return 0;
}

/* playback operators */
const struct snd_pcm_ops snd_line6_playback_ops = {
        .open = snd_line6_playback_open,
        .close = snd_line6_playback_close,
        .hw_params = snd_line6_hw_params,
        .hw_free = snd_line6_hw_free,
        .prepare = snd_line6_prepare,
        .trigger = snd_line6_trigger,
        .pointer = snd_line6_pointer,
};

int line6_create_audio_out_urbs(struct snd_line6_pcm *line6pcm)
{
        struct usb_line6 *line6 = line6pcm->line6;
        int i;

        line6pcm->out.urbs = kzalloc_objs(struct urb *, line6->iso_buffers);
        if (line6pcm->out.urbs == NULL)
                return -ENOMEM;

        /* create audio URBs and fill in constant values: */
        for (i = 0; i < line6->iso_buffers; ++i) {
                struct urb *urb;

                /* URB for audio out: */
                urb = line6pcm->out.urbs[i] =
                    usb_alloc_urb(LINE6_ISO_PACKETS, GFP_KERNEL);

                if (urb == NULL)
                        return -ENOMEM;

                urb->dev = line6->usbdev;
                urb->pipe =
                    usb_sndisocpipe(line6->usbdev,
                                    line6->properties->ep_audio_w &
                                    USB_ENDPOINT_NUMBER_MASK);
                urb->transfer_flags = URB_ISO_ASAP;
                urb->start_frame = -1;
                urb->number_of_packets = LINE6_ISO_PACKETS;
                urb->interval = LINE6_ISO_INTERVAL;
                urb->error_count = 0;
                urb->complete = audio_out_callback;
                if (usb_urb_ep_type_check(urb))
                        return -EINVAL;
        }

        return 0;
}