Hi Suman, On 4/8/20 10:52 PM, Suman Anna wrote: > On 4/8/20 10:59 AM, Mathieu Poirier wrote: >> On Tue, 7 Apr 2020 at 17:07, Suman Anna <s-anna@xxxxxx> wrote: >>> >>> Hi Mathieu, Arnaud, >>> >>> On 3/27/20 2:36 PM, Mathieu Poirier wrote: >>>> On Fri, Mar 27, 2020 at 10:35:34AM +0100, Arnaud POULIQUEN wrote: >>>>> Hi >>>>> >>>>> On 3/26/20 11:01 PM, Mathieu Poirier wrote: >>>>>> On Thu, 26 Mar 2020 at 14:42, Suman Anna <s-anna@xxxxxx> wrote: >>>>>>> >>>>>>> On 3/26/20 3:21 PM, Mathieu Poirier wrote: >>>>>>>> On Thu, 26 Mar 2020 at 09:06, Suman Anna <s-anna@xxxxxx> wrote: >>>>>>>>> >>>>>>>>> Hi Mathieu, >>>>>>>>> >>>>>>>>> On 3/10/20 10:50 AM, Mathieu Poirier wrote: >>>>>>>>>> Adding the capability to supplement the base definition published >>>>>>>>>> by an rpmsg_driver with a postfix description so that it is possible >>>>>>>>>> for several entity to use the same service. >>>>>>>>>> >>>>>>>>>> Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> >>>>>>>>>> Acked-by: Arnaud Pouliquen <arnaud.pouliquen@xxxxxx> >>>>>>>>> >>>>>>>>> So, the concern I have here is that we are retrofitting this into the >>>>>>>>> existing 32-byte name field, and the question is if it is going to be >>>>>>>>> enough in general. That's the reason I went with the additional 32-byte >>>>>>>>> field with the "rpmsg: add a description field" patch. >>>>>>>>> >>>>>>>> >>>>>>>> That's a valid concern. >>>>>>>> >>>>>>>> Did you consider increasing the size of RPMSG_NAME_SIZE to 64? Have >>>>>>>> you found cases where that wouldn't work? I did a survey of all the >>>>>>>> places the #define is used and all destination buffers are also using >>>>>>>> the same #define in their definition. It would also be backward >>>>>>>> compatible with firmware implementations that use 32 byte. >>>>>>> >>>>>>> You can't directly bump the size without breaking the compatibility on >>>>>>> the existing rpmsg_ns_msg in firmwares right? All the Linux-side drivers >>>>>>> will be ok since they use the same macro but rpmsg_ns_msg has presence >>>>>>> on both kernel and firmware-sides. >>>>>> >>>>>> Ah yes yes... The amount of bytes coming out of the pipe won't match. >>>>>> Let me think a little... >>>>> >>>>> +1 for Suman's concern. >>>>> >>>>> Anyway i would like to challenge the need of more than 32 bytes to >>>>> differentiate service instances. >>>>> "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA", seems to me enough if we only need >>>>> to differentiate the instances. >>> >>> Remember that the rpmsg_device_id name takes some space within here. So, >>> the shorter the rpmsg_device_id table name, the more room you have. >>> >>>>> >>>>> But perhaps the need is also to provide a short description of the service? >>> >>> I am mostly using it to provide a unique instantiation name. In anycase, >>> I have cross-checked against my current firmwares, and so far all of >>> them happen to have the name + desc < 31 bytes. >>> >>> >>>>> >>>>> Suman, could you share some examples of your need? >>>> >>>> Looking at things further it is possible to extend the name of the service to >>>> 64 byte while keeping backward compatibility by looking up the size of @len >>>> in function rpmsg_ns_cb(). From there work with an rpmsg_ns_msg or a new >>>> rpmsg_ns_msg64, pretty much the way you did in your patch[1]. In fact the >>>> approach is the same except you are using 2 arrays of 32 byte and I'm using one >>>> of 64. >>>> >>>> As Arnaud mentioned, is there an immediate need to support a 64-byte name? If >>>> not than I suggest to move forward with this patch and address the issue when we >>>> get there - at least we know there is room for extention. Otherwise I'll spin >>>> off another revision but it will be bigger and more complex. >>> >>> Yeah ok. I have managed to get my downstream drivers that use the desc >>> field working with this patch after modifying the firmwares to publish >>> using combined name, and adding logic in probe to get the trailing >>> portion of the name. >> >> Perfect >> >>> >>> So, the only thing that is missing or content for another patch is if we >>> need to add some tooling/helper stuff for giving the trailing stuff to >>> rpmsg drivers? >> >> So that all rpmsg drivers don't come up with their own parsing that >> ends up doing the same thing. Let me think about that - I may have to >> get back to you... > > Yep. Sure no problem. It can be a patch on top of this as well. > > Arnaud, > Do you have immediate need for the tooling stuff for the rpmsg-tty driver? Before moving forward on rpmsg_tty i would prefer that we are aligned with Bjorn on the implementation of the rpmsg_tty itself and the evolution of the service name... Then rpmsg_tty could be a good threadfor a first implementation... Concerning the name service, having a discussion around the name service skeleton would be nice. This could be an good input for the helpers function definition. Propositions in rpmsg_tty thread are <service_name>-<feature> or <service_name>-<feature>-<sub_service> don't hesitate to comment and/or propose alternatives Regards, Arnaud > > regards > Suman > > >> >>> >>> regards >>> Suman >>> >>>> >>>> Thanks, >>>> Mathieu >>>> >>>> [1]. https://patchwork.kernel.org/patch/11096599/ >>>> >>>>>>>>> >>>>>>>>>> --- >>>>>>>>>> Changes for V2: >>>>>>>>>> - Added Arnaud's Acked-by. >>>>>>>>>> - Rebased to latest rproc-next. >>>>>>>>>> >>>>>>>>>> drivers/rpmsg/rpmsg_core.c | 20 +++++++++++++++++++- >>>>>>>>>> 1 file changed, 19 insertions(+), 1 deletion(-) >>>>>>>>>> >>>>>>>>>> diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c >>>>>>>>>> index e330ec4dfc33..bfd25978fa35 100644 >>>>>>>>>> --- a/drivers/rpmsg/rpmsg_core.c >>>>>>>>>> +++ b/drivers/rpmsg/rpmsg_core.c >>>>>>>>>> @@ -399,7 +399,25 @@ ATTRIBUTE_GROUPS(rpmsg_dev); >>>>>>>>>> static inline int rpmsg_id_match(const struct rpmsg_device *rpdev, >>>>>>>>>> const struct rpmsg_device_id *id) >>>>>>>>>> { >>>>>>>>>> - return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0; >>>>>>>>>> + size_t len = min_t(size_t, strlen(id->name), RPMSG_NAME_SIZE); >>>>>>>>>> + >>>>>>>>>> + /* >>>>>>>>>> + * Allow for wildcard matches. For example if rpmsg_driver::id_table >>>>>>>>>> + * is: >>>>>>>>>> + * >>>>>>>>>> + * static struct rpmsg_device_id rpmsg_driver_sample_id_table[] = { >>>>>>>>>> + * { .name = "rpmsg-client-sample" }, >>>>>>>>>> + * { }, >>>>>>>>>> + * } >>>>>>>>>> + * >>>>>>>>>> + * Then it is possible to support "rpmsg-client-sample*", i.e: >>>>>>>>>> + * rpmsg-client-sample >>>>>>>>>> + * rpmsg-client-sample_instance0 >>>>>>>>>> + * rpmsg-client-sample_instance1 >>>>>>>>>> + * ... >>>>>>>>>> + * rpmsg-client-sample_instanceX >>>>>>>>>> + */ >>>>>>>>>> + return strncmp(id->name, rpdev->id.name, len) == 0; >>>>>>>>>> } >>>>>>>>>> >>>>>>>>>> /* match rpmsg channel and rpmsg driver */ >>>>>>>>>> >>>>>>>>> >>>>>>> >>> >
