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path: root/drivers/gpu/drm/xen/xen_drm_front.c
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Diffstat (limited to 'drivers/gpu/drm/xen/xen_drm_front.c')
-rw-r--r--drivers/gpu/drm/xen/xen_drm_front.c839
1 files changed, 839 insertions, 0 deletions
diff --git a/drivers/gpu/drm/xen/xen_drm_front.c b/drivers/gpu/drm/xen/xen_drm_front.c
new file mode 100644
index 000000000000..b3786c1a4e80
--- /dev/null
+++ b/drivers/gpu/drm/xen/xen_drm_front.c
@@ -0,0 +1,839 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+
+/*
+ * Xen para-virtual DRM device
+ *
+ * Copyright (C) 2016-2018 EPAM Systems Inc.
+ *
+ * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
+ */
+
+#include <drm/drmP.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_gem.h>
+
+#include <linux/of_device.h>
+
+#include <xen/platform_pci.h>
+#include <xen/xen.h>
+#include <xen/xenbus.h>
+
+#include <xen/interface/io/displif.h>
+
+#include "xen_drm_front.h"
+#include "xen_drm_front_cfg.h"
+#include "xen_drm_front_evtchnl.h"
+#include "xen_drm_front_gem.h"
+#include "xen_drm_front_kms.h"
+#include "xen_drm_front_shbuf.h"
+
+struct xen_drm_front_dbuf {
+ struct list_head list;
+ u64 dbuf_cookie;
+ u64 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, u64 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,
+ u64 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, u64 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, u64 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, u8 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(XEN_DRM_FRONT_WAIT_BACK_MS)) <= 0)
+ return -ETIMEDOUT;
+
+ return evtchnl->u.req.resp_status;
+}
+
+int xen_drm_front_mode_set(struct xen_drm_front_drm_pipeline *pipeline,
+ u32 x, u32 y, u32 width, u32 height,
+ u32 bpp, u64 fb_cookie)
+{
+ 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(&evtchnl->u.req.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(&evtchnl->u.req.req_io_lock);
+ return ret;
+}
+
+int xen_drm_front_dbuf_create(struct xen_drm_front_info *front_info,
+ u64 dbuf_cookie, u32 width, u32 height,
+ u32 bpp, u64 size, struct page **pages)
+{
+ 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.be_alloc = front_info->cfg.be_alloc;
+
+ shbuf = xen_drm_front_shbuf_alloc(&buf_cfg);
+ if (IS_ERR(shbuf))
+ return PTR_ERR(shbuf);
+
+ ret = dbuf_add_to_list(front_info, shbuf, dbuf_cookie);
+ if (ret < 0) {
+ xen_drm_front_shbuf_free(shbuf);
+ return ret;
+ }
+
+ mutex_lock(&evtchnl->u.req.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(&evtchnl->u.req.req_io_lock);
+ return 0;
+
+fail:
+ mutex_unlock(&evtchnl->u.req.req_io_lock);
+ dbuf_free(&front_info->dbuf_list, dbuf_cookie);
+ return ret;
+}
+
+static int xen_drm_front_dbuf_destroy(struct xen_drm_front_info *front_info,
+ u64 dbuf_cookie)
+{
+ 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(&evtchnl->u.req.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(&evtchnl->u.req.req_io_lock);
+ return ret;
+}
+
+int xen_drm_front_fb_attach(struct xen_drm_front_info *front_info,
+ u64 dbuf_cookie, u64 fb_cookie, u32 width,
+ u32 height, u32 pixel_format)
+{
+ 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(&evtchnl->u.req.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(&evtchnl->u.req.req_io_lock);
+ return ret;
+}
+
+int xen_drm_front_fb_detach(struct xen_drm_front_info *front_info,
+ u64 fb_cookie)
+{
+ 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(&evtchnl->u.req.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(&evtchnl->u.req.req_io_lock);
+ return ret;
+}
+
+int xen_drm_front_page_flip(struct xen_drm_front_info *front_info,
+ int conn_idx, u64 fb_cookie)
+{
+ 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(&evtchnl->u.req.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(&evtchnl->u.req.req_io_lock);
+ return ret;
+}
+
+void xen_drm_front_on_frame_done(struct xen_drm_front_info *front_info,
+ int conn_idx, u64 fb_cookie)
+{
+ struct xen_drm_front_drm_info *drm_info = front_info->drm_info;
+
+ if (unlikely(conn_idx >= front_info->cfg.num_connectors))
+ return;
+
+ xen_drm_front_kms_on_frame_done(&drm_info->pipeline[conn_idx],
+ fb_cookie);
+}
+
+static int xen_drm_drv_dumb_create(struct drm_file *filp,
+ struct drm_device *dev,
+ struct drm_mode_create_dumb *args)
+{
+ struct xen_drm_front_drm_info *drm_info = dev->dev_private;
+ struct drm_gem_object *obj;
+ int ret;
+
+ /*
+ * Dumb creation is a two stage process: first we create a fully
+ * constructed GEM object which is communicated to the backend, and
+ * only after that we can create GEM's handle. This is done so,
+ * because of the possible races: once you create a handle it becomes
+ * immediately visible to user-space, so the latter can try accessing
+ * object without pages etc.
+ * For details also see drm_gem_handle_create
+ */
+ args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
+ args->size = args->pitch * args->height;
+
+ obj = xen_drm_front_gem_create(dev, args->size);
+ if (IS_ERR_OR_NULL(obj)) {
+ ret = PTR_ERR(obj);
+ goto fail;
+ }
+
+ ret = xen_drm_front_dbuf_create(drm_info->front_info,
+ xen_drm_front_dbuf_to_cookie(obj),
+ args->width, args->height, args->bpp,
+ args->size,
+ xen_drm_front_gem_get_pages(obj));
+ if (ret)
+ goto fail_backend;
+
+ /* This is the tail of GEM object creation */
+ ret = drm_gem_handle_create(filp, obj, &args->handle);
+ if (ret)
+ goto fail_handle;
+
+ /* Drop reference from allocate - handle holds it now */
+ drm_gem_object_put_unlocked(obj);
+ return 0;
+
+fail_handle:
+ xen_drm_front_dbuf_destroy(drm_info->front_info,
+ xen_drm_front_dbuf_to_cookie(obj));
+fail_backend:
+ /* drop reference from allocate */
+ drm_gem_object_put_unlocked(obj);
+fail:
+ DRM_ERROR("Failed to create dumb buffer: %d\n", ret);
+ return ret;
+}
+
+static void xen_drm_drv_free_object_unlocked(struct drm_gem_object *obj)
+{
+ struct xen_drm_front_drm_info *drm_info = obj->dev->dev_private;
+ int idx;
+
+ if (drm_dev_enter(obj->dev, &idx)) {
+ xen_drm_front_dbuf_destroy(drm_info->front_info,
+ xen_drm_front_dbuf_to_cookie(obj));
+ drm_dev_exit(idx);
+ } else {
+ dbuf_free(&drm_info->front_info->dbuf_list,
+ xen_drm_front_dbuf_to_cookie(obj));
+ }
+
+ xen_drm_front_gem_free_object_unlocked(obj);
+}
+
+static void xen_drm_drv_release(struct drm_device *dev)
+{
+ struct xen_drm_front_drm_info *drm_info = dev->dev_private;
+ struct xen_drm_front_info *front_info = drm_info->front_info;
+
+ xen_drm_front_kms_fini(drm_info);
+
+ drm_atomic_helper_shutdown(dev);
+ drm_mode_config_cleanup(dev);
+
+ drm_dev_fini(dev);
+ kfree(dev);
+
+ if (front_info->cfg.be_alloc)
+ xenbus_switch_state(front_info->xb_dev,
+ XenbusStateInitialising);
+
+ kfree(drm_info);
+}
+
+static const struct file_operations xen_drm_dev_fops = {
+ .owner = THIS_MODULE,
+ .open = drm_open,
+ .release = drm_release,
+ .unlocked_ioctl = drm_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = drm_compat_ioctl,
+#endif
+ .poll = drm_poll,
+ .read = drm_read,
+ .llseek = no_llseek,
+ .mmap = xen_drm_front_gem_mmap,
+};
+
+static const struct vm_operations_struct xen_drm_drv_vm_ops = {
+ .open = drm_gem_vm_open,
+ .close = drm_gem_vm_close,
+};
+
+static struct drm_driver xen_drm_driver = {
+ .driver_features = DRIVER_GEM | DRIVER_MODESET |
+ DRIVER_PRIME | DRIVER_ATOMIC,
+ .release = xen_drm_drv_release,
+ .gem_vm_ops = &xen_drm_drv_vm_ops,
+ .gem_free_object_unlocked = xen_drm_drv_free_object_unlocked,
+ .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
+ .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
+ .gem_prime_import = drm_gem_prime_import,
+ .gem_prime_export = drm_gem_prime_export,
+ .gem_prime_import_sg_table = xen_drm_front_gem_import_sg_table,
+ .gem_prime_get_sg_table = xen_drm_front_gem_get_sg_table,
+ .gem_prime_vmap = xen_drm_front_gem_prime_vmap,
+ .gem_prime_vunmap = xen_drm_front_gem_prime_vunmap,
+ .gem_prime_mmap = xen_drm_front_gem_prime_mmap,
+ .dumb_create = xen_drm_drv_dumb_create,
+ .fops = &xen_drm_dev_fops,
+ .name = "xendrm-du",
+ .desc = "Xen PV DRM Display Unit",
+ .date = "20180221",
+ .major = 1,
+ .minor = 0,
+
+};
+
+static int xen_drm_drv_init(struct xen_drm_front_info *front_info)
+{
+ struct device *dev = &front_info->xb_dev->dev;
+ struct xen_drm_front_drm_info *drm_info;
+ struct drm_device *drm_dev;
+ int ret;
+
+ DRM_INFO("Creating %s\n", xen_drm_driver.desc);
+
+ drm_info = kzalloc(sizeof(*drm_info), GFP_KERNEL);
+ if (!drm_info) {
+ ret = -ENOMEM;
+ goto fail;
+ }
+
+ drm_info->front_info = front_info;
+ front_info->drm_info = drm_info;
+
+ drm_dev = drm_dev_alloc(&xen_drm_driver, dev);
+ if (IS_ERR(drm_dev)) {
+ ret = PTR_ERR(drm_dev);
+ goto fail;
+ }
+
+ drm_info->drm_dev = drm_dev;
+
+ drm_dev->dev_private = drm_info;
+
+ ret = xen_drm_front_kms_init(drm_info);
+ if (ret) {
+ DRM_ERROR("Failed to initialize DRM/KMS, ret %d\n", ret);
+ goto fail_modeset;
+ }
+
+ ret = drm_dev_register(drm_dev, 0);
+ if (ret)
+ goto fail_register;
+
+ DRM_INFO("Initialized %s %d.%d.%d %s on minor %d\n",
+ xen_drm_driver.name, xen_drm_driver.major,
+ xen_drm_driver.minor, xen_drm_driver.patchlevel,
+ xen_drm_driver.date, drm_dev->primary->index);
+
+ return 0;
+
+fail_register:
+ drm_dev_unregister(drm_dev);
+fail_modeset:
+ drm_kms_helper_poll_fini(drm_dev);
+ drm_mode_config_cleanup(drm_dev);
+fail:
+ kfree(drm_info);
+ return ret;
+}
+
+static void xen_drm_drv_fini(struct xen_drm_front_info *front_info)
+{
+ struct xen_drm_front_drm_info *drm_info = front_info->drm_info;
+ struct drm_device *dev;
+
+ if (!drm_info)
+ return;
+
+ dev = drm_info->drm_dev;
+ if (!dev)
+ return;
+
+ /* Nothing to do if device is already unplugged */
+ if (drm_dev_is_unplugged(dev))
+ return;
+
+ drm_kms_helper_poll_fini(dev);
+ drm_dev_unplug(dev);
+
+ front_info->drm_info = NULL;
+
+ xen_drm_front_evtchnl_free_all(front_info);
+ dbuf_free_all(&front_info->dbuf_list);
+
+ /*
+ * If we are not using backend allocated buffers, then tell the
+ * backend we are ready to (re)initialize. Otherwise, wait for
+ * drm_driver.release.
+ */
+ if (!front_info->cfg.be_alloc)
+ xenbus_switch_state(front_info->xb_dev,
+ XenbusStateInitialising);
+}
+
+static int displback_initwait(struct xen_drm_front_info *front_info)
+{
+ struct xen_drm_front_cfg *cfg = &front_info->cfg;
+ int ret;
+
+ cfg->front_info = front_info;
+ ret = xen_drm_front_cfg_card(front_info, cfg);
+ if (ret < 0)
+ return ret;
+
+ DRM_INFO("Have %d conector(s)\n", cfg->num_connectors);
+ /* Create event channels for all connectors and publish */
+ ret = xen_drm_front_evtchnl_create_all(front_info);
+ if (ret < 0)
+ return ret;
+
+ return xen_drm_front_evtchnl_publish_all(front_info);
+}
+
+static int displback_connect(struct xen_drm_front_info *front_info)
+{
+ xen_drm_front_evtchnl_set_state(front_info, EVTCHNL_STATE_CONNECTED);
+ return xen_drm_drv_init(front_info);
+}
+
+static void displback_disconnect(struct xen_drm_front_info *front_info)
+{
+ if (!front_info->drm_info)
+ return;
+
+ /* Tell the backend to wait until we release the DRM driver. */
+ xenbus_switch_state(front_info->xb_dev, XenbusStateReconfiguring);
+
+ xen_drm_drv_fini(front_info);
+}
+
+static void displback_changed(struct xenbus_device *xb_dev,
+ enum xenbus_state backend_state)
+{
+ struct xen_drm_front_info *front_info = dev_get_drvdata(&xb_dev->dev);
+ int ret;
+
+ DRM_DEBUG("Backend state is %s, front is %s\n",
+ xenbus_strstate(backend_state),
+ xenbus_strstate(xb_dev->state));
+
+ switch (backend_state) {
+ case XenbusStateReconfiguring:
+ /* fall through */
+ case XenbusStateReconfigured:
+ /* fall through */
+ case XenbusStateInitialised:
+ break;
+
+ case XenbusStateInitialising:
+ if (xb_dev->state == XenbusStateReconfiguring)
+ break;
+
+ /* recovering after backend unexpected closure */
+ displback_disconnect(front_info);
+ break;
+
+ case XenbusStateInitWait:
+ if (xb_dev->state == XenbusStateReconfiguring)
+ break;
+
+ /* recovering after backend unexpected closure */
+ displback_disconnect(front_info);
+ if (xb_dev->state != XenbusStateInitialising)
+ break;
+
+ ret = displback_initwait(front_info);
+ if (ret < 0)
+ xenbus_dev_fatal(xb_dev, ret, "initializing frontend");
+ else
+ xenbus_switch_state(xb_dev, XenbusStateInitialised);
+ break;
+
+ case XenbusStateConnected:
+ if (xb_dev->state != XenbusStateInitialised)
+ break;
+
+ ret = displback_connect(front_info);
+ if (ret < 0) {
+ displback_disconnect(front_info);
+ xenbus_dev_fatal(xb_dev, ret, "connecting backend");
+ } else {
+ xenbus_switch_state(xb_dev, XenbusStateConnected);
+ }
+ break;
+
+ case XenbusStateClosing:
+ /*
+ * in this state backend starts freeing resources,
+ * so let it go into closed state, so we can also
+ * remove ours
+ */
+ break;
+
+ case XenbusStateUnknown:
+ /* fall through */
+ case XenbusStateClosed:
+ if (xb_dev->state == XenbusStateClosed)
+ break;
+
+ displback_disconnect(front_info);
+ break;
+ }
+}
+
+static int xen_drv_probe(struct xenbus_device *xb_dev,
+ const struct xenbus_device_id *id)
+{
+ struct xen_drm_front_info *front_info;
+ struct device *dev = &xb_dev->dev;
+ int ret;
+
+ /*
+ * The device is not spawn from a device tree, so arch_setup_dma_ops
+ * is not called, thus leaving the device with dummy DMA ops.
+ * This makes the device return error on PRIME buffer import, which
+ * is not correct: to fix this call of_dma_configure() with a NULL
+ * node to set default DMA ops.
+ */
+ dev->coherent_dma_mask = DMA_BIT_MASK(32);
+ ret = of_dma_configure(dev, NULL, true);
+ if (ret < 0) {
+ DRM_ERROR("Cannot setup DMA ops, ret %d", ret);
+ return ret;
+ }
+
+ front_info = devm_kzalloc(&xb_dev->dev,
+ sizeof(*front_info), GFP_KERNEL);
+ if (!front_info)
+ return -ENOMEM;
+
+ front_info->xb_dev = xb_dev;
+ spin_lock_init(&front_info->io_lock);
+ INIT_LIST_HEAD(&front_info->dbuf_list);
+ dev_set_drvdata(&xb_dev->dev, front_info);
+
+ return xenbus_switch_state(xb_dev, XenbusStateInitialising);
+}
+
+static int xen_drv_remove(struct xenbus_device *dev)
+{
+ struct xen_drm_front_info *front_info = dev_get_drvdata(&dev->dev);
+ int to = 100;
+
+ xenbus_switch_state(dev, XenbusStateClosing);
+
+ /*
+ * On driver removal it is disconnected from XenBus,
+ * so no backend state change events come via .otherend_changed
+ * callback. This prevents us from exiting gracefully, e.g.
+ * signaling the backend to free event channels, waiting for its
+ * state to change to XenbusStateClosed and cleaning at our end.
+ * Normally when front driver removed backend will finally go into
+ * XenbusStateInitWait state.
+ *
+ * Workaround: read backend's state manually and wait with time-out.
+ */
+ while ((xenbus_read_unsigned(front_info->xb_dev->otherend, "state",
+ XenbusStateUnknown) != XenbusStateInitWait) &&
+ --to)
+ msleep(10);
+
+ if (!to) {
+ unsigned int state;
+
+ state = xenbus_read_unsigned(front_info->xb_dev->otherend,
+ "state", XenbusStateUnknown);
+ DRM_ERROR("Backend state is %s while removing driver\n",
+ xenbus_strstate(state));
+ }
+
+ xen_drm_drv_fini(front_info);
+ xenbus_frontend_closed(dev);
+ return 0;
+}
+
+static const struct xenbus_device_id xen_driver_ids[] = {
+ { XENDISPL_DRIVER_NAME },
+ { "" }
+};
+
+static struct xenbus_driver xen_driver = {
+ .ids = xen_driver_ids,
+ .probe = xen_drv_probe,
+ .remove = xen_drv_remove,
+ .otherend_changed = displback_changed,
+};
+
+static int __init xen_drv_init(void)
+{
+ /* At the moment we only support case with XEN_PAGE_SIZE == PAGE_SIZE */
+ if (XEN_PAGE_SIZE != PAGE_SIZE) {
+ DRM_ERROR(XENDISPL_DRIVER_NAME ": different kernel and Xen page sizes are not supported: XEN_PAGE_SIZE (%lu) != PAGE_SIZE (%lu)\n",
+ XEN_PAGE_SIZE, PAGE_SIZE);
+ return -ENODEV;
+ }
+
+ if (!xen_domain())
+ return -ENODEV;
+
+ if (!xen_has_pv_devices())
+ return -ENODEV;
+
+ DRM_INFO("Registering XEN PV " XENDISPL_DRIVER_NAME "\n");
+ return xenbus_register_frontend(&xen_driver);
+}
+
+static void __exit xen_drv_fini(void)
+{
+ DRM_INFO("Unregistering XEN PV " XENDISPL_DRIVER_NAME "\n");
+ xenbus_unregister_driver(&xen_driver);
+}
+
+module_init(xen_drv_init);
+module_exit(xen_drv_fini);
+
+MODULE_DESCRIPTION("Xen para-virtualized display device frontend");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("xen:" XENDISPL_DRIVER_NAME);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.