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. The new chardev 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 host-interface 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 v5.11. 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 15, 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 some preliminary 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! Andrew [0] https://www.intel.com/content/dam/www/program/design/us/en/documents/low-pin-count-interface-specification.pdf [1] https://github.com/openbmc/libmctp/ [2] https://www.dmtf.org/sites/default/files/standards/documents/DSP0236_1.3.1.pdf [3] https://github.com/openbmc/libmctp/blob/master/docs/bindings/vendor-astlpc.md [4] https://www.dmtf.org/sites/default/files/standards/documents/DSP0254_1.0.0.pdf [5] https://github.com/amboar/qemu/tree/kcs Andrew Jeffery (14): ipmi: kcs_bmc_aspeed: Use of match data to extract KCS properties ipmi: kcs_bmc: Make status update atomic ipmi: kcs_bmc: Rename {read,write}_{status,data}() functions ipmi: kcs_bmc: Split out kcs_bmc_cdev_ipmi ipmi: kcs_bmc: Turn the driver data-structures inside-out ipmi: kcs_bmc: Split headers into device and client ipmi: kcs_bmc: Strip private client data from struct kcs_bmc ipmi: kcs_bmc: Decouple the IPMI chardev from the core ipmi: kcs_bmc: Allow clients to control KCS IRQ state ipmi: kcs_bmc: Add a "raw" character device interface dt-bindings: ipmi: Convert ASPEED KCS binding to schema dt-bindings: ipmi: Add optional SerIRQ property to ASPEED KCS devices ipmi: kcs_bmc_aspeed: Implement KCS SerIRQ configuration ipmi: kcs_bmc_aspeed: Fix IBFIE typo from datasheet Chia-Wei, Wang (5): dt-bindings: aspeed-lpc: Remove LPC partitioning ARM: dts: Remove LPC BMC and Host partitions ipmi: kcs: aspeed: Adapt to new LPC DTS layout pinctrl: aspeed-g5: Adapt to new LPC device tree layout soc: aspeed: Adapt to new LPC device tree layout Documentation/ABI/testing/dev-raw-kcs | 25 + .../bindings/ipmi/aspeed,ast2400-kcs-bmc.yaml | 106 ++++ .../bindings/ipmi/aspeed-kcs-bmc.txt | 33 - .../devicetree/bindings/mfd/aspeed-lpc.txt | 100 +-- arch/arm/boot/dts/aspeed-g4.dtsi | 68 +-- arch/arm/boot/dts/aspeed-g5.dtsi | 119 ++-- arch/arm/boot/dts/aspeed-g6.dtsi | 121 ++-- drivers/char/ipmi/Kconfig | 30 + drivers/char/ipmi/Makefile | 2 + drivers/char/ipmi/kcs_bmc.c | 532 +++++----------- drivers/char/ipmi/kcs_bmc.h | 94 +-- drivers/char/ipmi/kcs_bmc_aspeed.c | 536 ++++++++++------ drivers/char/ipmi/kcs_bmc_cdev_ipmi.c | 570 ++++++++++++++++++ drivers/char/ipmi/kcs_bmc_cdev_raw.c | 442 ++++++++++++++ drivers/char/ipmi/kcs_bmc_client.h | 47 ++ drivers/char/ipmi/kcs_bmc_device.h | 20 + drivers/char/ipmi/kcs_bmc_npcm7xx.c | 98 ++- drivers/pinctrl/aspeed/pinctrl-aspeed-g5.c | 17 +- drivers/soc/aspeed/aspeed-lpc-ctrl.c | 20 +- drivers/soc/aspeed/aspeed-lpc-snoop.c | 23 +- 20 files changed, 2021 insertions(+), 982 deletions(-) create mode 100644 Documentation/ABI/testing/dev-raw-kcs create mode 100644 Documentation/devicetree/bindings/ipmi/aspeed,ast2400-kcs-bmc.yaml delete mode 100644 Documentation/devicetree/bindings/ipmi/aspeed-kcs-bmc.txt create mode 100644 drivers/char/ipmi/kcs_bmc_cdev_ipmi.c create mode 100644 drivers/char/ipmi/kcs_bmc_cdev_raw.c create mode 100644 drivers/char/ipmi/kcs_bmc_client.h create mode 100644 drivers/char/ipmi/kcs_bmc_device.h -- 2.27.0
