On Thu, Apr 08, 2021 at 10:27:46AM +0930, Andrew Jeffery wrote: > Hi Corey, > > On Fri, 19 Mar 2021, at 16:49, Andrew Jeffery wrote: > > Hello, > > > > This series is a bit of a mix of things, but its primary purpose is to > > expose BMC KCS IPMI devices to userspace in a way that enables userspace > > to talk to host firmware using protocols that are not IPMI. > > > > v1 can be found here: > > > > https://lore.kernel.org/openbmc/20210219142523.3464540-1-andrew@xxxxxxxx/ > > > > Changes in v2 include: > > > > * A rebase onto v5.12-rc2 > > * Incorporation of off-list feedback on SerIRQ configuration from > > Chiawei > > * Further validation on hardware for ASPEED KCS devices 2, 3 and 4 > > * Lifting the existing single-open constraint of the IPMI chardev > > * Fixes addressing Rob's feedback on the conversion of the ASPEED KCS > > binding to dt-schema > > * Fixes addressing Rob's feedback on the new aspeed,lpc-interrupts > > property definition for the ASPEED KCS binding > > > > A new chardev device is added whose implementation exposes the Input > > Data Register (IDR), Output Data Register (ODR) and Status Register > > (STR) via read() and write(), and implements poll() for event > > monitoring. > > > > The existing /dev/ipmi-kcs* chardev interface exposes the KCS devices in > > a way which encoded the IPMI protocol in its behaviour. However, as > > LPC[0] KCS devices give us bi-directional interrupts between the host > > and a BMC with both a data and status byte, they are useful for purposes > > beyond IPMI. > > > > As a concrete example, libmctp[1] implements a vendor-defined MCTP[2] > > binding using a combination of LPC Firmware cycles for bulk data > > transfer and a KCS device via LPC IO cycles for out-of-band protocol > > control messages[3]. This gives a throughput improvement over the > > standard KCS binding[4] while continuing to exploit the ease of setup of > > the LPC bus for early boot firmware on the host processor. > > > > The series takes a bit of a winding path to achieve its aim: > > > > 1. It begins with patches 1-5 put together by Chia-Wei, which I've > > rebased on v5.12-rc2. These fix the ASPEED LPC bindings and other > > non-KCS LPC-related ASPEED device drivers in a way that enables the > > SerIRQ patches at the end of the series. With Joel's review I'm hoping > > these 5 can go through the aspeed tree, and that the rest can go through > > the IPMI tree. > > > > 2. Next, patches 6-13 fairly heavily refactor the KCS support in the > > IPMI part of the tree, re-architecting things such that it's possible to > > support multiple chardev implementations sitting on top of the ASPEED > > and Nuvoton device drivers. However, the KCS code didn't really have > > great separation of concerns as it stood, so even if we disregard the > > multiple-chardev support I think the cleanups are worthwhile. > > > > 3. Patch 14 adds some interrupt management capabilities to the KCS > > device drivers in preparation for patch 16, which introduces the new > > "raw" KCS device interface. I'm not stoked about the device name/path, > > so if people are looking to bikeshed something then feel free to lay > > into that. > > > > 4. The remaining patches switch the ASPEED KCS devicetree binding to > > dt-schema, add a new interrupt property to describe the SerIRQ behaviour > > of the device and finally clean up Serial IRQ support in the ASPEED KCS > > driver. > > > > Rob: The dt-binding patches still come before the relevant driver > > changes, I tried to keep the two close together in the series, hence the > > bindings changes not being patches 1 and 2. > > > > I've exercised the series under qemu with the rainier-bmc machine plus > > additional patches for KCS support[5]. I've also substituted this series in > > place of a hacky out-of-tree driver that we've been using for the > > libmctp stack and successfully booted the host processor under our > > internal full-platform simulation tools for a Rainier system. > > > > Note that this work touches the Nuvoton driver as well as ASPEED's, but > > I don't have the capability to test those changes or the IPMI chardev > > path. Tested-by tags would be much appreciated if you can exercise one > > or both. > > > > Please review! > > Unfortunately the cover letter got detached from the rest of the series. > > Any chance you can take a look at the patches? There were some minor concerns that were unanswered, and there really was no review by others for many of the patches. I would like this patch set, it makes some good cleanups. But I would like some more review and testing by others, if possible. I'm fairly sure it has already been done, it just needs to be documented. -corey > > https://lore.kernel.org/linux-arm-kernel/20210319062752.145730-1-andrew@xxxxxxxx/ > > Cheers, > > Andrew
