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? 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 */ >>>>>>>>> >>>>>>>> >>>>>> >>
