hello Bjorn, On 10/08/2018 06:23 PM, Bjorn Andersson wrote: > On Mon 08 Oct 06:08 PDT 2018, Arnaud Pouliquen wrote: > >> Hi Arun, Bjorn, >> >> On 10/08/2018 08:38 AM, Arun Kumar Neelakantam wrote: >>> Glink transport support signals to exchange state notification between >>> local and remote side clients. Adding support to send/receive the signal >>> command and notify the clients through callback and POLL notification. >> >> Please correct me if i'm wrong...My concern here is that this patchset >> implements a rpmsg service in the rpmsg core. I would separate this from >> the rpmsg core, as this is not part of the rpmsg protocol but seems >> linked to the serial protocol itself. >> Could it be implemented in rpmsg_char, using a dedicated channel...? >> > > rpmsg_char does expose a rpmsg channel (be it virtio, smd or glink) to > user space. This patch series add support for invoking TIOCMGET and > TIOCMSET on these channels. I'm not familiar with this concept, that could explain that i don't understand this patchset... TIOCMGET and TIOCMSET is related to the serial/console flow control, to control remote modem/processor, right? it seems be implemented only to support the rpmsg_char ioctl interface. When i have a look to the glink code, signal is treated by a message sent to remote processor. Therefore it seems that it could be treated as a service on top of rpmsg (so treat it in rpmsg_char instead of extend the rpmsg protocol to treat it in glink driver). > > In addition to adding the client side of this to rpmsg_char it provides > this support for glink, but the same mechanism exists in smd - while > this is not supported (today) by the virtio rpmsg. This is my main concern, i would like to be sure that this service is not related to specific needs introduced by the rmpsg char implementation: In this case this should not be part of the rpmsg core but perhaps some ops directly provided to the rpmsg_char on registration (rpmsg_chrdev_register_device?)... > > > I'm uncertain of how we could implement this mechanism for virtio rpmsg, > given that it as a transport doesn't really have a concept of > channels/flows - but it's really useful to have! > > PS. rpmsg_set_signals() can be called from any rpmsg device to perform > flow control of the communication channel. For my point of view this patch-set extends the rpmsg protocol to add channel flow control. Does it make sense to have a flow control in rpmsg protocol? if yes, should it be linked to a channel or to the remote processor itself? Extra comment: associated documentation update is missing. Regards, Arnaud > > Regards, > Bjorn > >> Regards >> Arnaud >> >>> >>> Changes since v1: >>> - Split the patches as per functional areas like core, char, glink >>> - Add set, clear mask for TIOCMSET >>> - Merge the char signal callback and POLLPRI patches >>> >>> Changes since v2: >>> - Modify the rpmsg_get_signals function prototype >>> >>> Changes since v3: >>> - Correct the TICOMGET case handling as per new rpmsg_get_signals prototype >>> - Update the rpmsg_get_signals function header >>> >>> Arun Kumar Neelakantam (4): >>> rpmsg: core: Add signal API support >>> rpmsg: glink: Add support to handle signals command >>> rpmsg: char: Add TIOCMGET/TIOCMSET ioctl support >>> rpmsg: char: Add signal callback and POLLPRI support >>> >>> drivers/rpmsg/qcom_glink_native.c | 126 ++++++++++++++++++++++++++++++++++++++ >>> drivers/rpmsg/rpmsg_char.c | 74 +++++++++++++++++++++- >>> drivers/rpmsg/rpmsg_core.c | 41 +++++++++++++ >>> drivers/rpmsg/rpmsg_internal.h | 5 ++ >>> include/linux/rpmsg.h | 26 ++++++++ >>> 5 files changed, 269 insertions(+), 3 deletions(-) >>>
