On Mon 26 Jun 02:04 PDT 2017, Henri Roosen wrote: > On 06/25/2017 11:51 PM, Bjorn Andersson wrote: > > On Fri 02 Jun 04:35 PDT 2017, Henri Roosen wrote: > > > > > A device might not have an ops structure registered. This > > > patch fixes a null-prt dereference by checking ops before dereferencing > > > it. > > > > > > > In what scenario do you end up with a rpdev without ops defined? > > > > You need at least create_ept defined in your ops to be able to do any > > form of communication. So it would probably make more sense to add a > > sanity check in rpmsg_register_device(), but perhaps I'm missing > > something. > > I was trying to add support for the generic rpmsg-char driver for > virtio_rpmsg_bus. > > The rpmsg-char driver gets registered using rpmsg_chrdev_register_device(), > and IMHO this device should not have any > .ops. The chrdev is not used for communication, only for creating devices. > The devices which should have the .ops are the ones created using the > rpmsg-char device. > In order to create/open new channels from user space you need to call rpmsg_create_ept() and this require a rpmsg_device context in order for the communication to be associated with the appropriate link. So we must set up the rpmsg_device context with the ops table including create_ept() in order to maintain the reference back to the particular virtio device (or SMD channel). The main difference from previous implementations of this is that the rpmsg_device does not have a primary endpoint. This removes the need for the firmware to create a special channel to instantiate the user space communication, but comes at the cost of the special spawning from the individual backend drivers. Regards, Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-remoteproc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
