[PATCH v9 0/3] Add SSIF BMC driver

Quan Nguyen
2022-09-29T08:04:05Z

This series add support the SSIF BMC driver which is to perform in-band
IPMI communication with their host in management (BMC) side.

SSIF BMC driver in this series is tested with Aspeed AST2500 and AST2600

Discussion for v8:
https://lore.kernel.org/linux-arm-kernel/20220615090259.1121405-1-quan@os.amperecomputing.com/

v9:
+ Fix dependence with I2C subsystem [Randy]
+ Update missing Reviewed-by tag from v7 [Rob]
+ Remove useless error handling path [CJ]
+ Update comment for SSIF_ABORTING state [CJ]
+ Fix "unknown type name --u8" [kernel test robot]
+ Update commit message and add comment to explain
the effect of issuing RxCmdLast when Slave busy [Quan]

v8:
+ Dropped ssif_bmc.h file and move its content to ssif_bmc.c [Corey]
+ Add struct ipmi_ssif_msg to include/uapi/linux/ipmi_ssif_bmc.h
header file [Corey]
+ Use unsigned int for len field in struct ipmi_ssif_msg [Corey]
+ Avoid using packed structure [Corey]
+ Add comment to clarify the logic flow [Corey]
+ Fix multipart read end with len=0 issue [Corey]
+ Refactor code handle the too big request message [Corey]
+ Fix code indentation issue [Corey]
+ Clean buffer before receiving request to avoid garbage [Quan]
+ Fix the license to SPDX-License-Identifier: GPL-2.0-only [Quan]

v7:
+ Remove unnecessary del_timer() in response_timeout() [Corey]
+ Change compatible string from "ampere,ssif-bmc" to "ssif-bmc" [Jae]
+ Dropped the use of ssif_msg_len() macro, use the len directly [Quan]
+ Solve possible issue if both response timer and ssif_bmc_write()
occurred at the same time [Corey]
+ Fix wrong return type of ssif_bmc_poll() [kernel robot test]
+ Refactor and introduce ssif_part_buffer struct to replace the
response_buf to manage each send/receive part of ssif [Quan]
+ Change SSIF_BAD_SMBUS state to SSIF_ABORTING state [Corey]
+ Support abort feature to skip the current bad request/response and
wait until next new request [Corey]
+ Refactor the PEC calculation to avoid the re-calculate the PEC on
each I2C_SLAVE_WRITE_RECEIVED event [Quan]
+ Fix the use of error-proned idx [Corey]
+ Defer the test for valid SMBus command until the read/write part
is determined [Quan]
+ Change/split unsupported_smbus_cmd() to
supported_[write|read]_cmd() [Corey]
+ Abort the request if somehow its size exceeded 255 bytes [Quan]

v6:
+ Drop the use of slave_enable() [Wolfram]
+ Make i2c-aspeed to issue RxCmdLast command on all
I2C_SLAVE_WRITE_REQUESTED event to assert NAK when slave busy [Quan]
+ Make i2c slave to return -EBUSY when it's busy [Quan]
+ Drop the aborting feature as return Completion Code 0xFF may stop
host to retry and make ipmi_ssif.so fails to load [Quan]
+ Add timer to recover slave from busy state when no response [Quan]
+ Clean request/response buffer appropriately [Quan]
+ Add some minor change on error and warning messages [Quan]

v5:
+ Correct the patches order to fix the bisect issue found by
kernel build robot

v4:
+ Fix recursive spinlock [Graeme]
+ Send response with Completion code 0xFF when aborting [Quan]
+ Fix warning with dt_binding_check [Rob]
+ Change aspeed-ssif-bmc.yaml to ssif-bmc.yaml [Quan]
+ Added bounding check on SMBus writes and the whole request [Dan]
+ Moved buffer to end of struct ssif_bmc_ctx to avoid context
corruption if somehow buffer is written past the end [Dan]
+ Return -EINVAL if userspace buffer too small, don't
silence truncate [Corey, Joel]
+ Not necessary to check NONBLOCK in lock [Corey]
+ Enforce one user at a time [Joel]
+ Reject write with invalid response length from userspace [Corey]
+ Add state machines for better ssif bmc state handling [Quan]
+ Drop ssif_bmc_aspeed.c and make ssif_bmc.c is generic
SSIF BMC driver [Quan]
+ Change compatible string "aspeed,ast2500-ssif-bmc" to
"ampere,ssif-bmc" [Quan]
+ Toggle Slave enable in i2c-aspeed to turn on/off slave mode [Ryan]
+ Added slave_enable() to struct i2c_algorithm to control
slave mode and to address the recursive spinlock [Graeme, Ryan]
+ Abort current request with invalid SMBus write or
invalid command [Quan]
+ Abort all request if there is pending response [Quan]
+ Changed validate_pec() to validate_request() [Quan]
+ Add unsupported_smbus_cmd() to handle unknown SMBus command [Quan]
+ Print internal state string for ease investigating issue [Quan]
+ Move to READY state on SLAVE_STOP event [Quan]
+ Change initilize_transfer() to process_smbus_cmd() [Quan]
+ Introduce functions for each slave event [Quan]

v3:
+ Switched binding doc to use DT schema format [Rob]
+ Splited into generic ssif_bmc and aspeed-specific [Corey, Joel]
+ Removed redundant license info [Joel]
+ Switched to use traditional if-else [Joel]
+ Removed unused ssif_bmc_ioctl() [Joel]
+ Made handle_request()/complete_response() to return void [Joel]
+ Refactored send_ssif_bmc_response() and
receive_ssif_bmc_request() [Corey]
+ Remove mutex [Corey]
+ Use spin_lock/unlock_irqsave/restore in callback [Corey]
+ Removed the unnecessary memset [Corey]
+ Switch to use dev_err() [Corey]
+ Combine mask/unmask two interrupts together [Corey]
+ Fixed unhandled Tx done with NAK [Quan]
+ Late ack'ed Tx done w/wo Ack irq [Quan]
+ Use aspeed-specific exported aspeed_set_slave_busy() when
slave busy to fix the deadlock [Graeme, Philipp, Quan]
+ Clean buffer for last multipart read [Quan]
+ Handle unknown incoming command [Quan]

v2:
+ Fixed compiling error with COMPILE_TEST for arc

Quan Nguyen (3):
ipmi: ssif_bmc: Add SSIF BMC driver
bindings: ipmi: Add binding for SSIF BMC driver
i2c: aspeed: Assert NAK when slave is busy

.../devicetree/bindings/ipmi/ssif-bmc.yaml | 38 +
drivers/char/ipmi/Kconfig | 10 +
drivers/char/ipmi/Makefile | 1 +
drivers/char/ipmi/ssif_bmc.c | 873 ++++++++++++++++++
drivers/i2c/busses/i2c-aspeed.c | 9 +-
include/uapi/linux/ipmi_ssif_bmc.h | 18 +
6 files changed, 948 insertions(+), 1 deletion(-)
create mode 100644 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
create mode 100644 drivers/char/ipmi/ssif_bmc.c
create mode 100644 include/uapi/linux/ipmi_ssif_bmc.h

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2.35.1