| Message ID | 20171205010113.23263-1-cyril.bur@au1.ibm.com |
|---|---|
| Headers | show |
| Series | MBOX Protocol: Onwards to V3 | expand |
Cyril Bur <cyril.bur@au1.ibm.com> writes: > This is a respin of V2. The only real change I made is that we're > using a compile time check to ensure that the handler arrays are big > enough. This should catch mistakes when adding commands in the future. > The merged v3 spec used different command numbers than I expected, so > v2 did need a respin, I adjusted the constants. > > There are still caveats. There is currently no BMC v3 daemon. I have > tested it against a proof of concept by Suraj but that is quite > rudimentary testing at best. > > This series doesn't implement all of the V3 protocol. Skiboot doesn't > actually need to implement all of the protocol. If it isn't going to > use a command, it really doesn't need to have code for it. A future > patch can implement the functionality if we decide we want/need it. > > V2 cover-letter below. > > Firstly, let me apologise for the amount of rework in this series. > Ultimately the goal here was really the last three patches. > Unfortunately in the process of writing them I started thinking about > some of the problems in version 2. > > The easiest to address is a bug that came up in testing V3 which is > that if opening a window fails, skiboot will assume that the previously > opened window is still valid this is incorrect. Patch 2 address this > problem. > > Then I got to thinking about errors and timeouts. It turns out that > currently if mbox-flash decides a message times out, it will not be > able to send anymore due to the lpc-mbox driver needing a response for > every message it sent out - patch 4 deals with this. However after > writing a significantly less invasive fix I realised that the entire > handling of timeouts/retries/resends/late responses was racey. So a > much simpler version of patch 4 became patches 3-6. > > Then there was some extra version 2 stuff that wasn't necessary but is > nice to have - patch 7. > > Then on to actually implementing version 3 - at the time of writing > version 2 Suraj did suggest what has become patch 8. This actually > makes the version 3 patch - patch 9 very easy. > > The final patch is an extended, reworked and even more improved > version of the tests I sent with version 2 (which weren't merged at > the time) > > One final note: this series passes all the tests I can throw at it > however I do not have reliable access to a MBOX version 3 Daemon > running on real hardware. Suraj has been kind enough to use (very) > similar versions of this series in his testing and he informs me that > there are no problems, however this exact code has never run on real > hardware. > > Cyril Bur (11): > libflash/mbox-flash: Add v2 error codes > libflash/mbox-flash: Always close windows before opening a new window > libflash/mbox-flash: Move sequence handling to driver level > libflash/mbox-flash: Allow mbox-flash to tell the driver msg timeouts > hw/lpc-mbox: Simplify message bookkeeping and timeouts > libflash/mbox-flash: Simplify message sending > libflash/mbox-flash: Use BMC suggested timeout value > libflash/mbox-flash: Use static arrays of function pointers > libflash/mbox-flash: Understand v3 > libflash/mbox-flash: Add the ability to lock flash > libflash/test: Add tests for mbox-flash thanks, series merged to master as of b9774c47eecd0c90e503919432ec1e4a86355398. Even though we don't really have a v3 mbox daemon, the testing is valuable and this should be a place to start from and is probably "good enough" without shooting ourselves in the foot too hard when v3 mbox daemons start appearing.