greybus-dev December 2016

greybus-dev@lists.linaro.org

12 participants
6 discussions

[PATCH] staging: greybus: add host device function pointer checks

by Jason Hrycay

Add sanity checks for cport_quiesce and cport_clear before invoking the callbacks as these function pointers are not required during the host device registration. This follows the logic implemented elsewhere for various other function pointers. Signed-off-by: Jason Hrycay <jhrycay(a)gmail.com> --- drivers/staging/greybus/connection.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/staging/greybus/connection.c b/drivers/staging/greybus/connection.c index 833f83b..aa040b1 100644 --- a/drivers/staging/greybus/connection.c +++ b/drivers/staging/greybus/connection.c @@ -358,6 +358,9 @@ static int gb_connection_hd_cport_quiesce(struct gb_connection *connection) size_t peer_space; int ret; + if (!hd->driver->cport_quiesce) + return 0; + peer_space = sizeof(struct gb_operation_msg_hdr) + sizeof(struct gb_cport_shutdown_request); @@ -381,6 +384,9 @@ static int gb_connection_hd_cport_clear(struct gb_connection *connection) struct gb_host_device *hd = connection->hd; int ret; + if (!hd->driver->cport_clear) + return 0; + ret = hd->driver->cport_clear(hd, connection->hd_cport_id); if (ret) { dev_err(&hd->dev, "%s: failed to clear host cport: %d\n", -- 2.10.0

7 years, 11 months

[PATCH v2 0/2] staging: greybus: loopback fixes and updates

by Bryan O'Donoghue

Two simple patches here resulting from using greybus on gbsim and developing support for async. I found a bug in the user-space tool and while doing that decided to update the kernel thread to be better behaved when waiting for test completions. V2: Use available bundle pointer for dev_dbg printout - Johan Bryan O'Donoghue (2): staging: greybus: loopback: use gb_loopback_async_wait_all don't spin staging: greybus: loopback_test: Fix race preventing test completion drivers/staging/greybus/loopback.c | 11 +++++++++++ drivers/staging/greybus/tools/loopback_test.c | 10 +--------- 2 files changed, 12 insertions(+), 9 deletions(-) -- 2.7.4

7 years, 11 months

[PATCH v2 0/5] drivers/staging/greybus: add async operations

by Bryan O'Donoghue

V2: Scotty : "What are you standing around for - do you not know a jailbreak when you see one" ? Making sure to run format-patch against the right tree this time.. Updated meta-comments to highlight adding a generic async timeout - Johan Captured the result code of schedule_work/queue_work - Bryan Drop reference count on failure to submit schedule_work/queue_work - Bryan Added timeout suffix back to new gb_operation_request_send - Johan/Greg Updated Signed-off-by to my nexus-software.ie address - Bryan Iterated requisite Star Trek Quote - Bryan/Johan V4-private -> V1-public: McCOY: You've got him, Jim! You've got him where you want him. This patchset adds async operations to greybus-core. Rather than have different drivers do variations on the same theme of launching and timing out asynchronous operations, it makes sense instead to provide this functionality via greybus-core. This patchset makes it possible to launch asynchronous operations and have the completion callback for an operation indicate -ETIMEDOUT for timeouts without drivers having to manage that locally. This set doesn't convert the existing synchronous operations away from wait_for_completion_interruptible_timeout() since that would involve adding an extra work-queue item to each synchronous call, with no added benefit for synchronous operations. Synchronous operations can already detect -ETIMEDOUT by blocking on the synchronous send operations, asynchronous operations and the driver associated with those operations OTOH must implement a completion handler. The main improvement this patchset makes is to pass the -ETIMEDOUT completion status into that completion handler - hiding the setup/timeout of operations away from a driver-level and into a core-level set of logic. Loopback as an example can have lots and lots of redundant code removed and given we previously had some in-flight effort to add asynchronous operations to SDIO it makes sense to move the generic types of things we need to do on the asynchronous path into greybus-core so that SDIO and other bundle drivers can reuse instead of reimplement asynchronous operations. Note: we had approximately three internal versions of this on Project-Ara. Here's the log for completeness. V3-private -> V4-private: Fix bug in loopback conversion - Mitch Tasman V2-private -> V3-private: remotes/ara-main/sandbox/bodonoghue/ara-main-current+async_op3 Drop patch #6 converting sync operations to new t/o structure. Johan had a concern about doing an in-depth analysis on that change and considering our compressed timelines now, this analysis won't happen. OTOH the new async API is the right thing for loopback and for potential later greybus users/implementers to reuse. Although it wasn't part of the motive for this change - I observe slightly better performance than baseline with loopback tests with this change in place - which shouldn't be surprising since we have less aggregate context switching for operation timeouts. V1-private -> V2-private: Rename async_private => private - Greg gb_operation_request_send_async_timeout -> gb_operation_request_send_async() - Greg Using existing gb_operation_completion_wq - Viresh Split out gb_operation_cancel() - timeout need not wait synchronously on cancellation queue - Bryan Move timeout to work-queue - Greg/Viresh cancel timeout workqueue @ operation completion point - Viresh/Bryan Bryan O'Donoghue (5): staging: greybus: operation: add asynchronous gb_operation_cancel staging: greybus: operation: add generic asynchronous timeout operation support staging: greybus: operation: add private data with get/set accessors staging: greybus: loopback: convert loopback to use generic async operations staging: greybus: loopback: convert to use msecs internally drivers/staging/greybus/loopback.c | 181 ++++++++---------------------------- drivers/staging/greybus/operation.c | 85 ++++++++++++++++- drivers/staging/greybus/operation.h | 19 ++++ 3 files changed, 140 insertions(+), 145 deletions(-) -- 2.7.4

7 years, 11 months

[PATCH 0/2] staging: greybus: loopback fixes and updates

by Bryan O'Donoghue

Two simple patches here resulting from using greybus on gbsim and developing support for async. I found a bug in the user-space tool and while doing that decided to update the kernel thread to be better behaved when waiting for test completions. Bryan O'Donoghue (2): staging: greybus: loopback: use gb_loopback_async_wait_all don't spin staging: greybus: loopback_test: Fix race preventing test completion drivers/staging/greybus/loopback.c | 12 ++++++++++++ drivers/staging/greybus/tools/loopback_test.c | 10 +--------- 2 files changed, 13 insertions(+), 9 deletions(-) -- 2.7.4

8 years

New Development

by Alex Elder

OK now that we have lists and IRC in place, it's time to start using them. Bryan (at least) has posted some patches for review but if Greybus is going to provide some greater long-term usefulness it will need to be adapted to be more easily used in contexts outside Project Ara. There was some informal conversation about this at ELCE. I have a few of my own thoughts but mainly I just want to get some discussion started to see if we have some pieces we can agree on, and take things from there. Here's a short summary of what's below: - Retargeting Greybus for use in IoT seems reasonable - We will need to adjust the abstract model currently implemented for Greybus to match the new target - Certain core functionality should be useful as-is; but some other features will need to be re-thought and redefined. - We will need to evolve the Greybus kernel code to define what is truly "core" functionality, and what that core needs from its environment. - We will need to ensure the Greybus API is stable, and that our versioning design is sound. One thing that came up multiple times in October was the notion that Greybus could serve as the basis for communication among entities in an Internet of Things system. I agree with this, at least in part. We have set up a system with some well-defined mechanisms for encapsulating messages, along with a model of remote procedure calls that provide a pretty robust way of getting things done across a network. The core code implements a lot of features (like timeouts and message cancellation) that are very useful, and which should really be done in a generic way. We've got code and conventions in the existing protocol drivers that provide good examples of how to use the core functionality. I think it's reasonable to pursue adapting Greybus to be usable in IoT environments. In any case, one thing that occurred to me during that week and those discussions was that we really need to define a new *target* for Greybus. That is, we no longer have the Ara phone as the hardware target, and we need to somehow define another ultimate goal for the hardware or environment in which Greybus operates. This should be more abstract than a hardware definition; instead it ought to define properties of and services provided by the entities communicating in a Greybus system. In some ways we already have that (Interfaces and Modules are abstract, but the details of what they represent may no longer match what is required). I think the things that Greybus defines now that can be pretty universally useful are the core concepts: - generic Greybus host device driver interface - connections with fixed protocols that define how messages carried over them are interpreted - the format of messages, and the generic message header - the overall messaging model, including sending, receiving cancelling messages - the operations RPC model, including completion semantics (asynchronous completion, unidirectional operations, first error result prevails, and the ability to have multiple outstanding operations) >From there we get into some things that are almost certainly useful, but there may need to be some changes: - The grouping of connections into bundles, which attach to Linux device drivers. (I think we need this, but there remains some work to do, especially in relation to the next item.) - Manifests to describe module/interface functionality - Control connection and how it's used And we can keep going into other things that become more and more likely to be unnecessary or just plain wrong when we are targeting something different from an Ara phone: - SVC and the SVC protocol The above is not at all exhaustive; I just wanted to try to identify a few specific things we can maybe start to agree on. Currently, the control protocol and SVC protocol are very much biased toward the Ara hardware. (Other protocols are too, like time sync and maybe firmware update.) Furthermore, pieces of these have necessarily made their way into core Greybus code. As we define a new non-Ara target, we need to figure out what parts really belong in the Greybus core, and which things need to be supplied either by external entities or by protocol drivers. One way to do that might be to implement the core code as a library, but to be honest I think the real work lies in teasing things apart so the core can be defined to supply certain well-known services, with hooks to allow other capabilities. For a (contrived) example of what I mean, we may need to provide hooks for setting up connection routing rather than implementing it in the core code. In any case, I think we need to look at what constitutes the true "core" of Greybus services and what that core needs from its environment in order to be used. If Greybus is going to provide a more general service we need to ensure it provides a stable API. We have structured things this way since the beginning, but I fear we may have gotten sloppy because we basically always packaged everything together. As it is, all the versioning is in place but to my knowledge we've never really tested it to make sure it works. I had another point which I've now forgotten... In any case, I really just hope to get some conversation going. What do you think? -Alex

8 years

Android Things

by Karim Yaghmour

JFYI: https://developer.android.com/things/index.html There's no reason those APIs aren't tunneled over Greybus: https://developer.android.com/things/sdk/pio/index.html Oh wait, I've seen that somewhere before. -- Karim Yaghmour CEO - Opersys inc. / www.opersys.com http://twitter.com/karimyaghmour

8 years

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greybus-dev December 2016