[PATCH 9/9] drm/xen-front: Implement communication with backend
Daniel Vetter
daniel at ffwll.ch
Mon Mar 5 09:25:15 UTC 2018
On Wed, Feb 21, 2018 at 10:03:42AM +0200, Oleksandr Andrushchenko wrote:
> From: Oleksandr Andrushchenko <oleksandr_andrushchenko at epam.com>
>
> Handle communication with the backend:
> - send requests and wait for the responses according
> to the displif protocol
> - serialize access to the communication channel
> - time-out used for backend communication is set to 3000 ms
> - manage display buffers shared with the backend
>
> Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko at epam.com>
After the demidlayering it probably makes sense to merge this with the
overall kms/basic-drm-driver patch. Up to you really.
-Daniel
> ---
> drivers/gpu/drm/xen/xen_drm_front.c | 327 +++++++++++++++++++++++++++++++++++-
> drivers/gpu/drm/xen/xen_drm_front.h | 5 +
> 2 files changed, 327 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/xen/xen_drm_front.c b/drivers/gpu/drm/xen/xen_drm_front.c
> index 8de88e359d5e..5ad546231d30 100644
> --- a/drivers/gpu/drm/xen/xen_drm_front.c
> +++ b/drivers/gpu/drm/xen/xen_drm_front.c
> @@ -31,12 +31,146 @@
> #include "xen_drm_front_evtchnl.h"
> #include "xen_drm_front_shbuf.h"
>
> +/* timeout in ms to wait for backend to respond */
> +#define VDRM_WAIT_BACK_MS 3000
> +
> +struct xen_drm_front_dbuf {
> + struct list_head list;
> + uint64_t dbuf_cookie;
> + uint64_t fb_cookie;
> + struct xen_drm_front_shbuf *shbuf;
> +};
> +
> +static int dbuf_add_to_list(struct xen_drm_front_info *front_info,
> + struct xen_drm_front_shbuf *shbuf, uint64_t dbuf_cookie)
> +{
> + struct xen_drm_front_dbuf *dbuf;
> +
> + dbuf = kzalloc(sizeof(*dbuf), GFP_KERNEL);
> + if (!dbuf)
> + return -ENOMEM;
> +
> + dbuf->dbuf_cookie = dbuf_cookie;
> + dbuf->shbuf = shbuf;
> + list_add(&dbuf->list, &front_info->dbuf_list);
> + return 0;
> +}
> +
> +static struct xen_drm_front_dbuf *dbuf_get(struct list_head *dbuf_list,
> + uint64_t dbuf_cookie)
> +{
> + struct xen_drm_front_dbuf *buf, *q;
> +
> + list_for_each_entry_safe(buf, q, dbuf_list, list)
> + if (buf->dbuf_cookie == dbuf_cookie)
> + return buf;
> +
> + return NULL;
> +}
> +
> +static void dbuf_flush_fb(struct list_head *dbuf_list, uint64_t fb_cookie)
> +{
> + struct xen_drm_front_dbuf *buf, *q;
> +
> + list_for_each_entry_safe(buf, q, dbuf_list, list)
> + if (buf->fb_cookie == fb_cookie)
> + xen_drm_front_shbuf_flush(buf->shbuf);
> +}
> +
> +static void dbuf_free(struct list_head *dbuf_list, uint64_t dbuf_cookie)
> +{
> + struct xen_drm_front_dbuf *buf, *q;
> +
> + list_for_each_entry_safe(buf, q, dbuf_list, list)
> + if (buf->dbuf_cookie == dbuf_cookie) {
> + list_del(&buf->list);
> + xen_drm_front_shbuf_unmap(buf->shbuf);
> + xen_drm_front_shbuf_free(buf->shbuf);
> + kfree(buf);
> + break;
> + }
> +}
> +
> +static void dbuf_free_all(struct list_head *dbuf_list)
> +{
> + struct xen_drm_front_dbuf *buf, *q;
> +
> + list_for_each_entry_safe(buf, q, dbuf_list, list) {
> + list_del(&buf->list);
> + xen_drm_front_shbuf_unmap(buf->shbuf);
> + xen_drm_front_shbuf_free(buf->shbuf);
> + kfree(buf);
> + }
> +}
> +
> +static struct xendispl_req *be_prepare_req(
> + struct xen_drm_front_evtchnl *evtchnl, uint8_t operation)
> +{
> + struct xendispl_req *req;
> +
> + req = RING_GET_REQUEST(&evtchnl->u.req.ring,
> + evtchnl->u.req.ring.req_prod_pvt);
> + req->operation = operation;
> + req->id = evtchnl->evt_next_id++;
> + evtchnl->evt_id = req->id;
> + return req;
> +}
> +
> +static int be_stream_do_io(struct xen_drm_front_evtchnl *evtchnl,
> + struct xendispl_req *req)
> +{
> + reinit_completion(&evtchnl->u.req.completion);
> + if (unlikely(evtchnl->state != EVTCHNL_STATE_CONNECTED))
> + return -EIO;
> +
> + xen_drm_front_evtchnl_flush(evtchnl);
> + return 0;
> +}
> +
> +static int be_stream_wait_io(struct xen_drm_front_evtchnl *evtchnl)
> +{
> + if (wait_for_completion_timeout(&evtchnl->u.req.completion,
> + msecs_to_jiffies(VDRM_WAIT_BACK_MS)) <= 0)
> + return -ETIMEDOUT;
> +
> + return evtchnl->u.req.resp_status;
> +}
> +
> static int be_mode_set(struct xen_drm_front_drm_pipeline *pipeline, uint32_t x,
> uint32_t y, uint32_t width, uint32_t height, uint32_t bpp,
> uint64_t fb_cookie)
>
> {
> - return 0;
> + struct xen_drm_front_evtchnl *evtchnl;
> + struct xen_drm_front_info *front_info;
> + struct xendispl_req *req;
> + unsigned long flags;
> + int ret;
> +
> + front_info = pipeline->drm_info->front_info;
> + evtchnl = &front_info->evt_pairs[pipeline->index].req;
> + if (unlikely(!evtchnl))
> + return -EIO;
> +
> + mutex_lock(&front_info->req_io_lock);
> +
> + spin_lock_irqsave(&front_info->io_lock, flags);
> + req = be_prepare_req(evtchnl, XENDISPL_OP_SET_CONFIG);
> + req->op.set_config.x = x;
> + req->op.set_config.y = y;
> + req->op.set_config.width = width;
> + req->op.set_config.height = height;
> + req->op.set_config.bpp = bpp;
> + req->op.set_config.fb_cookie = fb_cookie;
> +
> + ret = be_stream_do_io(evtchnl, req);
> + spin_unlock_irqrestore(&front_info->io_lock, flags);
> +
> + if (ret == 0)
> + ret = be_stream_wait_io(evtchnl);
> +
> + mutex_unlock(&front_info->req_io_lock);
> + return ret;
> }
>
> static int be_dbuf_create_int(struct xen_drm_front_info *front_info,
> @@ -44,7 +178,69 @@ static int be_dbuf_create_int(struct xen_drm_front_info *front_info,
> uint32_t bpp, uint64_t size, struct page **pages,
> struct sg_table *sgt)
> {
> + struct xen_drm_front_evtchnl *evtchnl;
> + struct xen_drm_front_shbuf *shbuf;
> + struct xendispl_req *req;
> + struct xen_drm_front_shbuf_cfg buf_cfg;
> + unsigned long flags;
> + int ret;
> +
> + evtchnl = &front_info->evt_pairs[GENERIC_OP_EVT_CHNL].req;
> + if (unlikely(!evtchnl))
> + return -EIO;
> +
> + memset(&buf_cfg, 0, sizeof(buf_cfg));
> + buf_cfg.xb_dev = front_info->xb_dev;
> + buf_cfg.pages = pages;
> + buf_cfg.size = size;
> + buf_cfg.sgt = sgt;
> + buf_cfg.be_alloc = front_info->cfg.be_alloc;
> +
> + shbuf = xen_drm_front_shbuf_alloc(&buf_cfg);
> + if (!shbuf)
> + return -ENOMEM;
> +
> + ret = dbuf_add_to_list(front_info, shbuf, dbuf_cookie);
> + if (ret < 0) {
> + xen_drm_front_shbuf_free(shbuf);
> + return ret;
> + }
> +
> + mutex_lock(&front_info->req_io_lock);
> +
> + spin_lock_irqsave(&front_info->io_lock, flags);
> + req = be_prepare_req(evtchnl, XENDISPL_OP_DBUF_CREATE);
> + req->op.dbuf_create.gref_directory =
> + xen_drm_front_shbuf_get_dir_start(shbuf);
> + req->op.dbuf_create.buffer_sz = size;
> + req->op.dbuf_create.dbuf_cookie = dbuf_cookie;
> + req->op.dbuf_create.width = width;
> + req->op.dbuf_create.height = height;
> + req->op.dbuf_create.bpp = bpp;
> + if (buf_cfg.be_alloc)
> + req->op.dbuf_create.flags |= XENDISPL_DBUF_FLG_REQ_ALLOC;
> +
> + ret = be_stream_do_io(evtchnl, req);
> + spin_unlock_irqrestore(&front_info->io_lock, flags);
> +
> + if (ret < 0)
> + goto fail;
> +
> + ret = be_stream_wait_io(evtchnl);
> + if (ret < 0)
> + goto fail;
> +
> + ret = xen_drm_front_shbuf_map(shbuf);
> + if (ret < 0)
> + goto fail;
> +
> + mutex_unlock(&front_info->req_io_lock);
> return 0;
> +
> +fail:
> + mutex_unlock(&front_info->req_io_lock);
> + dbuf_free(&front_info->dbuf_list, dbuf_cookie);
> + return ret;
> }
>
> static int be_dbuf_create_from_sgt(struct xen_drm_front_info *front_info,
> @@ -66,26 +262,144 @@ static int be_dbuf_create_from_pages(struct xen_drm_front_info *front_info,
> static int be_dbuf_destroy(struct xen_drm_front_info *front_info,
> uint64_t dbuf_cookie)
> {
> - return 0;
> + struct xen_drm_front_evtchnl *evtchnl;
> + struct xendispl_req *req;
> + unsigned long flags;
> + bool be_alloc;
> + int ret;
> +
> + evtchnl = &front_info->evt_pairs[GENERIC_OP_EVT_CHNL].req;
> + if (unlikely(!evtchnl))
> + return -EIO;
> +
> + be_alloc = front_info->cfg.be_alloc;
> +
> + /*
> + * for the backend allocated buffer release references now, so backend
> + * can free the buffer
> + */
> + if (be_alloc)
> + dbuf_free(&front_info->dbuf_list, dbuf_cookie);
> +
> + mutex_lock(&front_info->req_io_lock);
> +
> + spin_lock_irqsave(&front_info->io_lock, flags);
> + req = be_prepare_req(evtchnl, XENDISPL_OP_DBUF_DESTROY);
> + req->op.dbuf_destroy.dbuf_cookie = dbuf_cookie;
> +
> + ret = be_stream_do_io(evtchnl, req);
> + spin_unlock_irqrestore(&front_info->io_lock, flags);
> +
> + if (ret == 0)
> + ret = be_stream_wait_io(evtchnl);
> +
> + /*
> + * do this regardless of communication status with the backend:
> + * if we cannot remove remote resources remove what we can locally
> + */
> + if (!be_alloc)
> + dbuf_free(&front_info->dbuf_list, dbuf_cookie);
> +
> + mutex_unlock(&front_info->req_io_lock);
> + return ret;
> }
>
> static int be_fb_attach(struct xen_drm_front_info *front_info,
> uint64_t dbuf_cookie, uint64_t fb_cookie, uint32_t width,
> uint32_t height, uint32_t pixel_format)
> {
> - return 0;
> + struct xen_drm_front_evtchnl *evtchnl;
> + struct xen_drm_front_dbuf *buf;
> + struct xendispl_req *req;
> + unsigned long flags;
> + int ret;
> +
> + evtchnl = &front_info->evt_pairs[GENERIC_OP_EVT_CHNL].req;
> + if (unlikely(!evtchnl))
> + return -EIO;
> +
> + buf = dbuf_get(&front_info->dbuf_list, dbuf_cookie);
> + if (!buf)
> + return -EINVAL;
> +
> + buf->fb_cookie = fb_cookie;
> +
> + mutex_lock(&front_info->req_io_lock);
> +
> + spin_lock_irqsave(&front_info->io_lock, flags);
> + req = be_prepare_req(evtchnl, XENDISPL_OP_FB_ATTACH);
> + req->op.fb_attach.dbuf_cookie = dbuf_cookie;
> + req->op.fb_attach.fb_cookie = fb_cookie;
> + req->op.fb_attach.width = width;
> + req->op.fb_attach.height = height;
> + req->op.fb_attach.pixel_format = pixel_format;
> +
> + ret = be_stream_do_io(evtchnl, req);
> + spin_unlock_irqrestore(&front_info->io_lock, flags);
> +
> + if (ret == 0)
> + ret = be_stream_wait_io(evtchnl);
> +
> + mutex_unlock(&front_info->req_io_lock);
> + return ret;
> }
>
> static int be_fb_detach(struct xen_drm_front_info *front_info,
> uint64_t fb_cookie)
> {
> - return 0;
> + struct xen_drm_front_evtchnl *evtchnl;
> + struct xendispl_req *req;
> + unsigned long flags;
> + int ret;
> +
> + evtchnl = &front_info->evt_pairs[GENERIC_OP_EVT_CHNL].req;
> + if (unlikely(!evtchnl))
> + return -EIO;
> +
> + mutex_lock(&front_info->req_io_lock);
> +
> + spin_lock_irqsave(&front_info->io_lock, flags);
> + req = be_prepare_req(evtchnl, XENDISPL_OP_FB_DETACH);
> + req->op.fb_detach.fb_cookie = fb_cookie;
> +
> + ret = be_stream_do_io(evtchnl, req);
> + spin_unlock_irqrestore(&front_info->io_lock, flags);
> +
> + if (ret == 0)
> + ret = be_stream_wait_io(evtchnl);
> +
> + mutex_unlock(&front_info->req_io_lock);
> + return ret;
> }
>
> static int be_page_flip(struct xen_drm_front_info *front_info, int conn_idx,
> uint64_t fb_cookie)
> {
> - return 0;
> + struct xen_drm_front_evtchnl *evtchnl;
> + struct xendispl_req *req;
> + unsigned long flags;
> + int ret;
> +
> + if (unlikely(conn_idx >= front_info->num_evt_pairs))
> + return -EINVAL;
> +
> + dbuf_flush_fb(&front_info->dbuf_list, fb_cookie);
> + evtchnl = &front_info->evt_pairs[conn_idx].req;
> +
> + mutex_lock(&front_info->req_io_lock);
> +
> + spin_lock_irqsave(&front_info->io_lock, flags);
> + req = be_prepare_req(evtchnl, XENDISPL_OP_PG_FLIP);
> + req->op.pg_flip.fb_cookie = fb_cookie;
> +
> + ret = be_stream_do_io(evtchnl, req);
> + spin_unlock_irqrestore(&front_info->io_lock, flags);
> +
> + if (ret == 0)
> + ret = be_stream_wait_io(evtchnl);
> +
> + mutex_unlock(&front_info->req_io_lock);
> + return ret;
> }
>
> static void xen_drm_drv_unload(struct xen_drm_front_info *front_info)
> @@ -183,6 +497,7 @@ static void xen_drv_remove_internal(struct xen_drm_front_info *front_info)
> {
> xen_drm_drv_deinit(front_info);
> xen_drm_front_evtchnl_free_all(front_info);
> + dbuf_free_all(&front_info->dbuf_list);
> }
>
> static int backend_on_initwait(struct xen_drm_front_info *front_info)
> @@ -310,6 +625,8 @@ static int xen_drv_probe(struct xenbus_device *xb_dev,
>
> front_info->xb_dev = xb_dev;
> spin_lock_init(&front_info->io_lock);
> + mutex_init(&front_info->req_io_lock);
> + INIT_LIST_HEAD(&front_info->dbuf_list);
> front_info->drm_pdrv_registered = false;
> dev_set_drvdata(&xb_dev->dev, front_info);
> return xenbus_switch_state(xb_dev, XenbusStateInitialising);
> diff --git a/drivers/gpu/drm/xen/xen_drm_front.h b/drivers/gpu/drm/xen/xen_drm_front.h
> index c6f52c892434..db32d00145d1 100644
> --- a/drivers/gpu/drm/xen/xen_drm_front.h
> +++ b/drivers/gpu/drm/xen/xen_drm_front.h
> @@ -137,6 +137,8 @@ struct xen_drm_front_info {
> struct xenbus_device *xb_dev;
> /* to protect data between backend IO code and interrupt handler */
> spinlock_t io_lock;
> + /* serializer for backend IO: request/response */
> + struct mutex req_io_lock;
> bool drm_pdrv_registered;
> /* virtual DRM platform device */
> struct platform_device *drm_pdev;
> @@ -144,6 +146,9 @@ struct xen_drm_front_info {
> int num_evt_pairs;
> struct xen_drm_front_evtchnl_pair *evt_pairs;
> struct xen_drm_front_cfg cfg;
> +
> + /* display buffers */
> + struct list_head dbuf_list;
> };
>
> #endif /* __XEN_DRM_FRONT_H_ */
> --
> 2.7.4
>
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> dri-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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