// SPDX-License-Identifier: GPL-2.0+
/*
 *      uvc_video.c  --  USB Video Class Gadget driver
 *
 *      Copyright (C) 2009-2010
 *          Laurent Pinchart (laurent.pinchart@ideasonboard.com)
 */

#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>
#include <linux/usb/video.h>
#include <asm/unaligned.h>

#include <media/v4l2-dev.h>

#include "uvc.h"
#include "uvc_queue.h"
#include "uvc_video.h"

/* --------------------------------------------------------------------------
 * Video codecs
 */

static int
uvc_video_encode_header(struct uvc_video *video, struct uvc_buffer *buf,
                u8 *data, int len)
{
        struct uvc_device *uvc = container_of(video, struct uvc_device, video);
        struct usb_composite_dev *cdev = uvc->func.config->cdev;
        struct timespec64 ts = ns_to_timespec64(buf->buf.vb2_buf.timestamp);
        int pos = 2;

        data[1] = UVC_STREAM_EOH | video->fid;

        if (video->queue.buf_used == 0 && ts.tv_sec) {
                /* dwClockFrequency is 48 MHz */
                u32 pts = ((u64)ts.tv_sec * USEC_PER_SEC + ts.tv_nsec / NSEC_PER_USEC) * 48;

                data[1] |= UVC_STREAM_PTS;
                put_unaligned_le32(pts, &data[pos]);
                pos += 4;
        }

        if (cdev->gadget->ops->get_frame) {
                u32 sof, stc;

                sof = usb_gadget_frame_number(cdev->gadget);
                ktime_get_ts64(&ts);
                stc = ((u64)ts.tv_sec * USEC_PER_SEC + ts.tv_nsec / NSEC_PER_USEC) * 48;

                data[1] |= UVC_STREAM_SCR;
                put_unaligned_le32(stc, &data[pos]);
                put_unaligned_le16(sof, &data[pos+4]);
                pos += 6;
        }

        data[0] = pos;

        if (buf->bytesused - video->queue.buf_used <= len - pos)
                data[1] |= UVC_STREAM_EOF;

        return pos;
}

static int
uvc_video_encode_data(struct uvc_video *video, struct uvc_buffer *buf,
                u8 *data, int len)
{
        struct uvc_video_queue *queue = &video->queue;
        unsigned int nbytes;
        void *mem;

        /* Copy video data to the USB buffer. */
        mem = buf->mem + queue->buf_used;
        nbytes = min((unsigned int)len, buf->bytesused - queue->buf_used);

        memcpy(data, mem, nbytes);
        queue->buf_used += nbytes;

        return nbytes;
}

static void
uvc_video_encode_bulk(struct usb_request *req, struct uvc_video *video,
                struct uvc_buffer *buf)
{
        void *mem = req->buf;
        int len = video->req_size;
        int ret;

        /* Add a header at the beginning of the payload. */
        if (video->payload_size == 0) {
                ret = uvc_video_encode_header(video, buf, mem, len);
                video->payload_size += ret;
                mem += ret;
                len -= ret;
        }

        /* Process video data. */
        len = min((int)(video->max_payload_size - video->payload_size), len);
        ret = uvc_video_encode_data(video, buf, mem, len);

        video->payload_size += ret;
        len -= ret;

        req->length = video->req_size - len;
        req->zero = video->payload_size == video->max_payload_size;

        if (buf->bytesused == video->queue.buf_used) {
                video->queue.buf_used = 0;
                buf->state = UVC_BUF_STATE_DONE;
                uvcg_queue_next_buffer(&video->queue, buf);
                video->fid ^= UVC_STREAM_FID;

                video->payload_size = 0;
        }

        if (video->payload_size == video->max_payload_size ||
            buf->bytesused == video->queue.buf_used)
                video->payload_size = 0;
}

static void
uvc_video_encode_isoc_sg(struct usb_request *req, struct uvc_video *video,
                struct uvc_buffer *buf)
{
        unsigned int pending = buf->bytesused - video->queue.buf_used;
        struct uvc_request *ureq = req->context;
        struct scatterlist *sg, *iter;
        unsigned int len = video->req_size;
        unsigned int sg_left, part = 0;
        unsigned int i;
        int header_len;

        sg = ureq->sgt.sgl;
        sg_init_table(sg, ureq->sgt.nents);

        /* Init the header. */
        header_len = uvc_video_encode_header(video, buf, ureq->header,
                                      video->req_size);
        sg_set_buf(sg, ureq->header, header_len);
        len -= header_len;

        if (pending <= len)
                len = pending;

        req->length = (len == pending) ?
                len + header_len : video->req_size;

        /* Init the pending sgs with payload */
        sg = sg_next(sg);

        for_each_sg(sg, iter, ureq->sgt.nents - 1, i) {
                if (!len || !buf->sg)
                        break;

                sg_left = sg_dma_len(buf->sg) - buf->offset;
                part = min_t(unsigned int, len, sg_left);

                sg_set_page(iter, sg_page(buf->sg), part, buf->offset);

                if (part == sg_left) {
                        buf->offset = 0;
                        buf->sg = sg_next(buf->sg);
                } else {
                        buf->offset += part;
                }
                len -= part;
        }

        /* Assign the video data with header. */
        req->buf = NULL;
        req->sg = ureq->sgt.sgl;
        req->num_sgs = i + 1;

        req->length -= len;
        video->queue.buf_used += req->length - header_len;

        if (buf->bytesused == video->queue.buf_used || !buf->sg) {
                video->queue.buf_used = 0;
                buf->state = UVC_BUF_STATE_DONE;
                buf->offset = 0;
                uvcg_queue_next_buffer(&video->queue, buf);
                video->fid ^= UVC_STREAM_FID;
        }
}

static void
uvc_video_encode_isoc(struct usb_request *req, struct uvc_video *video,
                struct uvc_buffer *buf)
{
        void *mem = req->buf;
        int len = video->req_size;
        int ret;

        /* Add the header. */
        ret = uvc_video_encode_header(video, buf, mem, len);
        mem += ret;
        len -= ret;

        /* Process video data. */
        ret = uvc_video_encode_data(video, buf, mem, len);
        len -= ret;

        req->length = video->req_size - len;

        if (buf->bytesused == video->queue.buf_used) {
                video->queue.buf_used = 0;
                buf->state = UVC_BUF_STATE_DONE;
                uvcg_queue_next_buffer(&video->queue, buf);
                video->fid ^= UVC_STREAM_FID;
        }
}

/* --------------------------------------------------------------------------
 * Request handling
 */

static int uvcg_video_ep_queue(struct uvc_video *video, struct usb_request *req)
{
        int ret;

        ret = usb_ep_queue(video->ep, req, GFP_ATOMIC);
        if (ret < 0) {
                uvcg_err(&video->uvc->func, "Failed to queue request (%d).\n",
                         ret);

                /* If the endpoint is disabled the descriptor may be NULL. */
                if (video->ep->desc) {
                        /* Isochronous endpoints can't be halted. */
                        if (usb_endpoint_xfer_bulk(video->ep->desc))
                                usb_ep_set_halt(video->ep);
                }
        }

        return ret;
}

static void
uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
{
        struct uvc_request *ureq = req->context;
        struct uvc_video *video = ureq->video;
        struct uvc_video_queue *queue = &video->queue;
        struct uvc_device *uvc = video->uvc;
        unsigned long flags;

        switch (req->status) {
        case 0:
                break;

        case -ESHUTDOWN:        /* disconnect from host. */
                uvcg_dbg(&video->uvc->func, "VS request cancelled.\n");
                uvcg_queue_cancel(queue, 1);
                break;

        default:
                uvcg_info(&video->uvc->func,
                          "VS request completed with status %d.\n",
                          req->status);
                uvcg_queue_cancel(queue, 0);
        }

        spin_lock_irqsave(&video->req_lock, flags);
        list_add_tail(&req->list, &video->req_free);
        spin_unlock_irqrestore(&video->req_lock, flags);

        if (uvc->state == UVC_STATE_STREAMING)
                schedule_work(&video->pump);
}

static int
uvc_video_free_requests(struct uvc_video *video)
{
        unsigned int i;

        if (video->ureq) {
                for (i = 0; i < video->uvc_num_requests; ++i) {
                        sg_free_table(&video->ureq[i].sgt);

                        if (video->ureq[i].req) {
                                usb_ep_free_request(video->ep, video->ureq[i].req);
                                video->ureq[i].req = NULL;
                        }

                        if (video->ureq[i].req_buffer) {
                                kfree(video->ureq[i].req_buffer);
                                video->ureq[i].req_buffer = NULL;
                        }
                }

                kfree(video->ureq);
                video->ureq = NULL;
        }

        INIT_LIST_HEAD(&video->req_free);
        video->req_size = 0;
        return 0;
}

static int
uvc_video_alloc_requests(struct uvc_video *video)
{
        unsigned int req_size;
        unsigned int i;
        int ret = -ENOMEM;

        BUG_ON(video->req_size);

        req_size = video->ep->maxpacket
                 * max_t(unsigned int, video->ep->maxburst, 1)
                 * (video->ep->mult);

        video->ureq = kcalloc(video->uvc_num_requests, sizeof(struct uvc_request), GFP_KERNEL);
        if (video->ureq == NULL)
                return -ENOMEM;

        for (i = 0; i < video->uvc_num_requests; ++i) {
                video->ureq[i].req_buffer = kmalloc(req_size, GFP_KERNEL);
                if (video->ureq[i].req_buffer == NULL)
                        goto error;

                video->ureq[i].req = usb_ep_alloc_request(video->ep, GFP_KERNEL);
                if (video->ureq[i].req == NULL)
                        goto error;

                video->ureq[i].req->buf = video->ureq[i].req_buffer;
                video->ureq[i].req->length = 0;
                video->ureq[i].req->complete = uvc_video_complete;
                video->ureq[i].req->context = &video->ureq[i];
                video->ureq[i].video = video;

                list_add_tail(&video->ureq[i].req->list, &video->req_free);
                /* req_size/PAGE_SIZE + 1 for overruns and + 1 for header */
                sg_alloc_table(&video->ureq[i].sgt,
                               DIV_ROUND_UP(req_size - UVCG_REQUEST_HEADER_LEN,
                                            PAGE_SIZE) + 2, GFP_KERNEL);
        }

        video->req_size = req_size;

        return 0;

error:
        uvc_video_free_requests(video);
        return ret;
}

/* --------------------------------------------------------------------------
 * Video streaming
 */

/*
 * uvcg_video_pump - Pump video data into the USB requests
 *
 * This function fills the available USB requests (listed in req_free) with
 * video data from the queued buffers.
 */
static void uvcg_video_pump(struct work_struct *work)
{
        struct uvc_video *video = container_of(work, struct uvc_video, pump);
        struct uvc_video_queue *queue = &video->queue;
        struct usb_request *req = NULL;
        struct uvc_buffer *buf;
        unsigned long flags;
        int ret;

        while (video->ep->enabled) {
                /* Retrieve the first available USB request, protected by the
                 * request lock.
                 */
                spin_lock_irqsave(&video->req_lock, flags);
                if (list_empty(&video->req_free)) {
                        spin_unlock_irqrestore(&video->req_lock, flags);
                        return;
                }
                req = list_first_entry(&video->req_free, struct usb_request,
                                        list);
                list_del(&req->list);
                spin_unlock_irqrestore(&video->req_lock, flags);

                /* Retrieve the first available video buffer and fill the
                 * request, protected by the video queue irqlock.
                 */
                spin_lock_irqsave(&queue->irqlock, flags);
                buf = uvcg_queue_head(queue);
                if (buf == NULL) {
                        spin_unlock_irqrestore(&queue->irqlock, flags);
                        break;
                }

                video->encode(req, video, buf);

                /* With usb3 we have more requests. This will decrease the
                 * interrupt load to a quarter but also catches the corner
                 * cases, which needs to be handled */
                if (list_empty(&video->req_free) ||
                    buf->state == UVC_BUF_STATE_DONE ||
                    !(video->req_int_count %
                       DIV_ROUND_UP(video->uvc_num_requests, 4))) {
                        video->req_int_count = 0;
                        req->no_interrupt = 0;
                } else {
                        req->no_interrupt = 1;
                }

                /* Queue the USB request */
                ret = uvcg_video_ep_queue(video, req);
                spin_unlock_irqrestore(&queue->irqlock, flags);

                if (ret < 0) {
                        uvcg_queue_cancel(queue, 0);
                        break;
                }
                video->req_int_count++;
        }

        if (!req)
                return;

        spin_lock_irqsave(&video->req_lock, flags);
        list_add_tail(&req->list, &video->req_free);
        spin_unlock_irqrestore(&video->req_lock, flags);
        return;
}

/*
 * Enable or disable the video stream.
 */
int uvcg_video_enable(struct uvc_video *video, int enable)
{
        unsigned int i;
        int ret;

        if (video->ep == NULL) {
                uvcg_info(&video->uvc->func,
                          "Video enable failed, device is uninitialized.\n");
                return -ENODEV;
        }

        if (!enable) {
                cancel_work_sync(&video->pump);
                uvcg_queue_cancel(&video->queue, 0);

                for (i = 0; i < video->uvc_num_requests; ++i)
                        if (video->ureq && video->ureq[i].req)
                                usb_ep_dequeue(video->ep, video->ureq[i].req);

                uvc_video_free_requests(video);
                uvcg_queue_enable(&video->queue, 0);
                return 0;
        }

        if ((ret = uvcg_queue_enable(&video->queue, 1)) < 0)
                return ret;

        if ((ret = uvc_video_alloc_requests(video)) < 0)
                return ret;

        if (video->max_payload_size) {
                video->encode = uvc_video_encode_bulk;
                video->payload_size = 0;
        } else
                video->encode = video->queue.use_sg ?
                        uvc_video_encode_isoc_sg : uvc_video_encode_isoc;

        video->req_int_count = 0;

        schedule_work(&video->pump);

        return ret;
}

/*
 * Initialize the UVC video stream.
 */
int uvcg_video_init(struct uvc_video *video, struct uvc_device *uvc)
{
        INIT_LIST_HEAD(&video->req_free);
        spin_lock_init(&video->req_lock);
        INIT_WORK(&video->pump, uvcg_video_pump);

        video->uvc = uvc;
        video->fcc = V4L2_PIX_FMT_YUYV;
        video->bpp = 16;
        video->width = 320;
        video->height = 240;
        video->imagesize = 320 * 240 * 2;

        /* Initialize the video buffers queue. */
        uvcg_queue_init(&video->queue, uvc->v4l2_dev.dev->parent,
                        V4L2_BUF_TYPE_VIDEO_OUTPUT, &video->mutex);
        return 0;
}