Hi Sakari,

On Wednesday, May 03, 2017 11:58:01 Sakari Ailus wrote:
> Hi Yong,
> 
> A few more minor comments below...
> 
> On Sat, Apr 29, 2017 at 06:34:36PM -0500, Yong Zhi wrote:
> ...
> > +/******* V4L2 sub-device asynchronous registration callbacks***********/
> > +
> > +static struct cio2_queue *cio2_find_queue_by_sensor_node(struct cio2_queue 
> > *q,
> > +                                           struct fwnode_handle *fwnode)
> > +{
> > +   int i;
> > +
> > +   for (i = 0; i < CIO2_QUEUES; i++) {
> > +           if (q[i].sensor->fwnode == fwnode)
> > +                   return &q[i];
> > +   }
> > +
> > +   return NULL;
> > +}
> > +
> > +/* The .bound() notifier callback when a match is found */
> > +static int cio2_notifier_bound(struct v4l2_async_notifier *notifier,
> > +                          struct v4l2_subdev *sd,
> > +                          struct v4l2_async_subdev *asd)
> > +{
> > +   struct cio2_device *cio2 = container_of(notifier,
> > +                                   struct cio2_device, notifier);
> > +   struct sensor_async_subdev *s_asd = container_of(asd,
> > +                                   struct sensor_async_subdev, asd);
> > +   struct cio2_queue *q;
> > +   struct device *dev;
> > +   int i;
> > +
> > +   dev = &cio2->pci_dev->dev;
> > +
> > +   /* Find first free slot for the subdev */
> > +   for (i = 0; i < CIO2_QUEUES; i++)
> > +           if (!cio2->queue[i].sensor)
> > +                   break;
> > +
> > +   if (i >= CIO2_QUEUES) {
> > +           dev_err(dev, "too many subdevs\n");
> > +           return -ENOSPC;
> > +   }
> > +   q = &cio2->queue[i];
> > +
> > +   q->csi2.port = s_asd->vfwn_endpt.base.port;
> > +   q->csi2.num_of_lanes = s_asd->vfwn_endpt.bus.mipi_csi2.num_data_lanes;
> > +   q->sensor = sd;
> > +   q->csi_rx_base = cio2->base + CIO2_REG_PIPE_BASE(q->csi2.port);
> > +
> > +   return 0;
> > +}
> > +
> > +/* The .unbind callback */
> > +static void cio2_notifier_unbind(struct v4l2_async_notifier *notifier,
> > +                            struct v4l2_subdev *sd,
> > +                            struct v4l2_async_subdev *asd)
> > +{
> > +   struct cio2_device *cio2 = container_of(notifier,
> > +                                           struct cio2_device, notifier);
> > +   unsigned int i;
> > +
> > +   /* Note: sd may here point to unallocated memory. Do not access. */
> 
> When can this happen?

If v4l2_device_register_subdev() fails, it may lead to
calling subdevice's remove function and the devres system
freeing the subdevice before unbind is called. This did
happen during driver development.

> 
> > +   for (i = 0; i < CIO2_QUEUES; i++) {
> > +           if (cio2->queue[i].sensor == sd) {
> > +                   cio2->queue[i].sensor = NULL;
> > +                   return;
> > +           }
> > +   }
> > +}
> > +
> > +/* .complete() is called after all subdevices have been located */
> > +static int cio2_notifier_complete(struct v4l2_async_notifier *notifier)
> > +{
> > +   struct cio2_device *cio2 = container_of(notifier, struct cio2_device,
> > +                                           notifier);
> > +   struct sensor_async_subdev *s_asd;
> > +   struct fwnode_handle *fwn_remote, *fwn_endpt, *fwn_remote_endpt;
> > +   struct cio2_queue *q;
> > +   struct fwnode_endpoint remote_endpt;
> > +   int i, ret;
> > +
> > +   for (i = 0; i < notifier->num_subdevs; i++) {
> > +           s_asd = container_of(cio2->notifier.subdevs[i],
> > +                                   struct sensor_async_subdev,
> > +                                   asd);
> 
> Fits on previous line. It's a good practice to align the further function
> arguments wrapped on the following lines to the character just right of the
> opening parenthesis, e.g.
> 
> ret = foo(bar,
>         foobar);
> 
> > +
> > +           fwn_remote = s_asd->asd.match.fwnode.fwn;
> > +           fwn_endpt = (struct fwnode_handle *)
> > +                                   s_asd->vfwn_endpt.base.local_fwnode;
> > +           fwn_remote_endpt = fwnode_graph_get_remote_endpoint(fwn_endpt);
> > +           if (!fwn_remote_endpt) {
> > +                   dev_err(&cio2->pci_dev->dev,
> > +                                   "failed to get remote endpt %d\n", ret);
> > +                   return ret;
> > +           }
> > +
> > +           ret = fwnode_graph_parse_endpoint(fwn_remote_endpt,
> > +                                                   &remote_endpt);
> > +           if (ret) {
> > +                   dev_err(&cio2->pci_dev->dev,
> > +                           "failed to parse remote endpt %d\n", ret);
> > +                   return ret;
> > +           }
> > +
> > +           q = cio2_find_queue_by_sensor_node(cio2->queue, fwn_remote);
> > +           if (!q) {
> > +                   dev_err(&cio2->pci_dev->dev,
> > +                                   "failed to find cio2 queue %d\n", ret);
> > +                   return ret;
> > +           }
> > +
> > +           ret = media_create_pad_link(
> > +                           &q->sensor->entity, remote_endpt.id,
> > +                           &q->subdev.entity, s_asd->vfwn_endpt.base.id,
> > +                           0);
> > +           if (ret) {
> > +                   dev_err(&cio2->pci_dev->dev,
> > +                                   "failed to create link for %s\n",
> > +                                   cio2->queue[i].sensor->name);
> > +                   return ret;
> > +           }
> > +   }
> > +
> > +   return v4l2_device_register_subdev_nodes(&cio2->v4l2_dev);
> > +}
> > +
> > +static int cio2_notifier_init(struct cio2_device *cio2)
> > +{
> > +   struct device *dev;
> > +   struct fwnode_handle *dev_fwn, *fwn, *fwn_remote;
> > +   struct v4l2_async_subdev *asd;
> > +   struct sensor_async_subdev *s_asd;
> > +   int ret, endpt_i;
> > +
> > +   dev = &cio2->pci_dev->dev;
> > +   dev_fwn = dev_fwnode(dev);
> > +
> > +   asd = devm_kzalloc(dev, sizeof(asd) * CIO2_QUEUES, GFP_KERNEL);
> > +   if (!asd)
> > +           return -ENOMEM;
> > +
> > +   cio2->notifier.subdevs = (struct v4l2_async_subdev **)asd;
> > +   cio2->notifier.num_subdevs = 0;
> 
> No need to initialise to zero --- it's already zero.
> 
> > +   cio2->notifier.bound = cio2_notifier_bound;
> > +   cio2->notifier.unbind = cio2_notifier_unbind;
> > +   cio2->notifier.complete = cio2_notifier_complete;
> > +
> > +   fwn = NULL;
> > +   endpt_i = 0;
> 
> You could initialise these in variable declaration.
> 
> > +   while (endpt_i < CIO2_QUEUES &&
> > +                   (fwn = fwnode_graph_get_next_endpoint(dev_fwn, fwn))) {
> > +           s_asd = devm_kzalloc(dev, sizeof(*s_asd), GFP_KERNEL);
> > +           if (!asd)
> > +                   return -ENOMEM;
> > +
> > +           fwn_remote = fwnode_graph_get_remote_port_parent(fwn);
> > +           if (!fwn_remote) {
> > +                   dev_err(dev, "bad remote port parent\n");
> > +                   return -ENOENT;
> > +           }
> > +
> > +           ret = v4l2_fwnode_endpoint_parse(fwn, &s_asd->vfwn_endpt);
> > +           if (ret) {
> > +                   dev_err(dev, "endpoint parsing error : %d\n", ret);
> > +                   return ret;
> > +           }
> > +
> > +           if (s_asd->vfwn_endpt.bus_type != V4L2_MBUS_CSI2) {
> > +                   dev_warn(dev, "endpoint bus type error\n");
> > +                   devm_kfree(dev, s_asd);
> > +                   continue;
> > +           }
> > +
> > +           s_asd->asd.match.fwnode.fwn = fwn_remote;
> > +           s_asd->asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
> > +
> > +           cio2->notifier.subdevs[endpt_i++] = &s_asd->asd;
> > +   }
> > +
> > +   if (!endpt_i)
> > +           return 0;       /* No endpoint */
> > +
> > +   cio2->notifier.num_subdevs = endpt_i;
> 
> You only use endpt_i in a single location. How about dropping it and using
> cio2->notifier.num_subdevs instead?
> 
> > +   ret = v4l2_async_notifier_register(&cio2->v4l2_dev, &cio2->notifier);
> > +   if (ret) {
> > +           cio2->notifier.num_subdevs = 0;
> > +           dev_err(dev, "failed to register async notifier : %d\n", ret);
> > +           return ret;
> > +   }
> > +
> > +   return 0;
> > +}
> > +
> > +static void cio2_notifier_exit(struct cio2_device *cio2)
> > +{
> > +   if (cio2->notifier.num_subdevs > 0)
> > +           v4l2_async_notifier_unregister(&cio2->notifier);
> > +}
> > +
> > +/**************** Queue initialization ****************/
> > +static const struct media_entity_operations cio2_media_ops = {
> > +   .link_validate = v4l2_subdev_link_validate,
> > +};
> > +
> > +int cio2_queue_init(struct cio2_device *cio2, struct cio2_queue *q)
> > +{
> > +   static const u32 default_width = 1936;
> > +   static const u32 default_height = 1096;
> > +   static const u32 default_mbusfmt = MEDIA_BUS_FMT_SRGGB10_1X10;
> > +
> > +   struct video_device *vdev = &q->vdev;
> > +   struct vb2_queue *vbq = &q->vbq;
> > +   struct v4l2_subdev *subdev = &q->subdev;
> > +   struct v4l2_mbus_framefmt *fmt;
> > +   int r;
> > +
> > +   /* Initialize miscellaneous variables */
> > +   mutex_init(&q->lock);
> > +
> > +   /* Initialize formats to default values */
> > +   fmt = &q->subdev_fmt;
> > +   fmt->width = default_width;
> > +   fmt->height = default_height;
> > +   fmt->code = default_mbusfmt;
> > +   fmt->field = V4L2_FIELD_NONE;
> > +   fmt->colorspace = V4L2_COLORSPACE_RAW;
> > +   fmt->ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
> > +   fmt->quantization = V4L2_QUANTIZATION_DEFAULT;
> > +   fmt->xfer_func = V4L2_XFER_FUNC_DEFAULT;
> > +
> > +   q->pixelformat = V4L2_PIX_FMT_IPU3_SRGGB10;
> > +
> > +   /* Initialize fbpt */
> > +   r = cio2_fbpt_init(cio2, q);
> > +   if (r)
> > +           goto fail_fbpt;
> > +
> > +   /* Initialize media entities */
> > +   r = media_entity_pads_init(&subdev->entity, CIO2_PADS, q->subdev_pads);
> > +   if (r) {
> > +           dev_err(&cio2->pci_dev->dev,
> > +                   "failed initialize subdev media entity (%d)\n", r);
> > +           goto fail_subdev_media_entity;
> > +   }
> > +   q->subdev_pads[CIO2_PAD_SINK].flags = MEDIA_PAD_FL_SINK |
> > +           MEDIA_PAD_FL_MUST_CONNECT;
> > +   q->subdev_pads[CIO2_PAD_SOURCE].flags = MEDIA_PAD_FL_SOURCE;
> > +   subdev->entity.ops = &cio2_media_ops;
> > +   r = media_entity_pads_init(&vdev->entity, 1, &q->vdev_pad);
> > +   if (r) {
> > +           dev_err(&cio2->pci_dev->dev,
> > +                   "failed initialize videodev media entity (%d)\n", r);
> > +           goto fail_vdev_media_entity;
> > +   }
> > +   q->vdev_pad.flags = MEDIA_PAD_FL_SINK | MEDIA_PAD_FL_MUST_CONNECT;
> > +   vdev->entity.ops = &cio2_media_ops;
> > +
> > +   /* Initialize subdev */
> > +   v4l2_subdev_init(subdev, &cio2_subdev_ops);
> > +   subdev->flags = V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_HAS_EVENTS;
> > +   subdev->owner = THIS_MODULE;
> > +   snprintf(subdev->name, sizeof(subdev->name),
> > +            CIO2_ENTITY_NAME ":%li", q - cio2->queue);
> > +   v4l2_set_subdevdata(subdev, cio2);
> > +   r = v4l2_device_register_subdev(&cio2->v4l2_dev, subdev);
> > +   if (r) {
> > +           dev_err(&cio2->pci_dev->dev,
> > +                   "failed initialize subdev (%d)\n", r);
> > +           goto fail_subdev;
> > +   }
> > +
> > +   /* Initialize vbq */
> > +   vbq->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> > +   vbq->io_modes = VB2_USERPTR | VB2_MMAP;
> > +   vbq->ops = &cio2_vb2_ops;
> > +   vbq->mem_ops = &vb2_dma_sg_memops;
> > +   vbq->buf_struct_size = sizeof(struct cio2_buffer);
> > +   vbq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
> > +   vbq->min_buffers_needed = 1;
> > +   vbq->drv_priv = cio2;
> > +   vbq->lock = &q->lock;
> > +   r = vb2_queue_init(vbq);
> > +   if (r) {
> > +           dev_err(&cio2->pci_dev->dev,
> > +                   "failed to initialize videobuf2 queue (%d)\n", r);
> > +           goto fail_vbq;
> > +   }
> > +
> > +   /* Initialize vdev */
> > +   snprintf(vdev->name, sizeof(vdev->name),
> > +            "%s:%li", CIO2_NAME, q - cio2->queue);
> > +   vdev->release = video_device_release_empty;
> > +   vdev->fops = &cio2_v4l2_fops;
> > +   vdev->ioctl_ops = &cio2_v4l2_ioctl_ops;
> > +   vdev->lock = &cio2->lock;
> > +   vdev->v4l2_dev = &cio2->v4l2_dev;
> > +   vdev->queue = &q->vbq;
> > +   video_set_drvdata(vdev, cio2);
> > +   r = video_register_device(vdev, VFL_TYPE_GRABBER, -1);
> > +   if (r) {
> > +           dev_err(&cio2->pci_dev->dev,
> > +                   "failed to register video device (%d)\n", r);
> > +           goto fail_vdev;
> > +   }
> > +
> > +   /* Create link from CIO2 subdev to output node */
> > +   r = media_create_pad_link(
> > +           &subdev->entity, CIO2_PAD_SOURCE, &vdev->entity, 0,
> > +           MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
> > +   if (r)
> > +           goto fail_link;
> > +
> > +   return 0;
> > +
> > +fail_link:
> > +   video_unregister_device(&q->vdev);
> > +fail_vdev:
> > +   vb2_queue_release(vbq);
> > +fail_vbq:
> > +   v4l2_device_unregister_subdev(subdev);
> > +fail_subdev:
> > +   media_entity_cleanup(&vdev->entity);
> > +fail_vdev_media_entity:
> > +   media_entity_cleanup(&subdev->entity);
> > +fail_subdev_media_entity:
> > +   cio2_fbpt_exit(q, &cio2->pci_dev->dev);
> > +fail_fbpt:
> > +   mutex_destroy(&q->lock);
> > +
> > +   return r;
> > +}
> > +
> > +static void cio2_queue_exit(struct cio2_device *cio2, struct cio2_queue *q)
> > +{
> > +   video_unregister_device(&q->vdev);
> > +   vb2_queue_release(&q->vbq);
> > +   v4l2_device_unregister_subdev(&q->subdev);
> > +   media_entity_cleanup(&q->vdev.entity);
> > +   media_entity_cleanup(&q->subdev.entity);
> > +   cio2_fbpt_exit(q, &cio2->pci_dev->dev);
> > +   mutex_destroy(&q->lock);
> > +}
> > +
> > +/**************** PCI interface ****************/
> > +
> > +static int cio2_pci_config_setup(struct pci_dev *dev)
> > +{
> > +   u16 pci_command;
> > +   int r = pci_enable_msi(dev);
> 
> It's a good practice to obtain local references to data structures you need
> in a function while you're declaring variables but I wouldn't enable MSI
> here. Instead do:
> 
> int r;
> 
> r = pci_enable_msi();
> 
> > +
> > +   if (r) {
> > +           dev_err(&dev->dev, "failed to enable MSI (%d)\n", r);
> > +           return r;
> > +   }
> > +
> > +   pci_read_config_word(dev, PCI_COMMAND, &pci_command);
> > +   pci_command |= PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER |
> > +           PCI_COMMAND_INTX_DISABLE;
> > +   pci_write_config_word(dev, PCI_COMMAND, pci_command);
> > +
> > +   return 0;
> > +}
> > +
> > +static int cio2_pci_probe(struct pci_dev *pci_dev,
> > +                     const struct pci_device_id *id)
> > +{
> > +   struct cio2_device *cio2;
> > +   phys_addr_t phys;
> > +   void __iomem *const *iomap;
> > +   int i = -1, r = -ENODEV;
> 
> No need to initialise r. It's soon assigned again.
> 
> > +
> > +   cio2 = devm_kzalloc(&pci_dev->dev, sizeof(*cio2), GFP_KERNEL);
> > +   if (!cio2)
> > +           return -ENOMEM;
> > +   cio2->pci_dev = pci_dev;
> > +
> > +   r = pcim_enable_device(pci_dev);
> > +   if (r) {
> > +           dev_err(&pci_dev->dev, "failed to enable device (%d)\n", r);
> > +           return r;
> > +   }
> > +
> > +   dev_info(&pci_dev->dev, "device 0x%x (rev: 0x%x)\n",
> > +            pci_dev->device, pci_dev->revision);
> > +
> > +   phys = pci_resource_start(pci_dev, CIO2_PCI_BAR);
> > +
> > +   r = pcim_iomap_regions(pci_dev, 1 << CIO2_PCI_BAR, pci_name(pci_dev));
> > +   if (r) {
> > +           dev_err(&pci_dev->dev, "failed to remap I/O memory (%d)\n", r);
> > +           return -ENODEV;
> > +   }
> > +
> > +   iomap = pcim_iomap_table(pci_dev);
> > +   if (!iomap) {
> > +           dev_err(&pci_dev->dev, "failed to iomap table\n");
> > +           return -ENODEV;
> > +   }
> > +
> > +   cio2->base = iomap[CIO2_PCI_BAR];
> > +
> > +   pci_set_drvdata(pci_dev, cio2);
> > +
> > +   pci_set_master(pci_dev);
> > +
> > +   r = pci_set_dma_mask(pci_dev, CIO2_DMA_MASK);
> > +   if (r) {
> > +           dev_err(&pci_dev->dev, "failed to set DMA mask (%d)\n", r);
> > +           return -ENODEV;
> > +   }
> > +
> > +   r = cio2_pci_config_setup(pci_dev);
> > +   if (r)
> > +           return -ENODEV;
> > +
> > +   mutex_init(&cio2->lock);
> > +
> > +   cio2->media_dev.dev = &cio2->pci_dev->dev;
> > +   strlcpy(cio2->media_dev.model, CIO2_DEVICE_NAME,
> > +           sizeof(cio2->media_dev.model));
> > +   snprintf(cio2->media_dev.bus_info, sizeof(cio2->media_dev.bus_info),
> > +            "PCI:%s", pci_name(cio2->pci_dev));
> > +   cio2->media_dev.driver_version = KERNEL_VERSION(4, 11, 0);
> > +   cio2->media_dev.hw_revision = 0;
> > +
> > +   media_device_init(&cio2->media_dev);
> > +   r = media_device_register(&cio2->media_dev);
> > +   if (r < 0)
> > +           goto fail_mutex_destroy;
> > +
> > +   cio2->v4l2_dev.mdev = &cio2->media_dev;
> > +   r = v4l2_device_register(&pci_dev->dev, &cio2->v4l2_dev);
> > +   if (r) {
> > +           dev_err(&pci_dev->dev,
> > +                   "failed to register V4L2 device (%d)\n", r);
> > +           goto fail_mutex_destroy;
> > +   }
> > +
> > +   for (i = 0; i < CIO2_QUEUES; i++) {
> > +           r = cio2_queue_init(cio2, &cio2->queue[i]);
> > +           if (r)
> > +                   goto fail;
> > +   }
> > +
> > +   r = cio2_fbpt_init_dummy(cio2);
> > +   if (r)
> > +           goto fail;
> > +
> > +   /* Register notifier for subdevices we care */
> > +   r = cio2_notifier_init(cio2);
> > +   if (r)
> > +           goto fail;
> > +
> > +   r = devm_request_irq(&pci_dev->dev, pci_dev->irq, cio2_irq,
> > +                        IRQF_SHARED, CIO2_NAME, cio2);
> > +   if (r) {
> > +           dev_err(&pci_dev->dev, "failed to request IRQ (%d)\n", r);
> > +           goto fail;
> > +   }
> > +
> > +   pm_runtime_put_noidle(&pci_dev->dev);
> > +   pm_runtime_allow(&pci_dev->dev);
> > +
> > +   return 0;
> > +
> > +fail:
> > +   cio2_notifier_exit(cio2);
> > +   cio2_fbpt_exit_dummy(cio2);
> > +   for (; i >= 0; i--)
> > +           cio2_queue_exit(cio2, &cio2->queue[i]);
> > +   v4l2_device_unregister(&cio2->v4l2_dev);
> > +   media_device_unregister(&cio2->media_dev);
> > +   media_device_cleanup(&cio2->media_dev);
> > +fail_mutex_destroy:
> > +   mutex_destroy(&cio2->lock);
> > +
> > +   return r;
> > +}
> 
> 

--
Regards,
- Tuukka

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