Re: [PATCH v7 0/3] Add SSIF BMC driver

[Quan Nguyen <quan@os.amperecomputing.com>]

Added Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
as I'm not aware of the email change
- Quan

On 22/04/2022 11:08, Quan Nguyen wrote:
> 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.
> 
> Discussion for v6: https://lkml.org/lkml/2022/3/10/340
> 
> 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                     |  11 +
>   drivers/char/ipmi/Makefile                    |   1 +
>   drivers/char/ipmi/ssif_bmc.c                  | 780 ++++++++++++++++++
>   drivers/char/ipmi/ssif_bmc.h                  | 107 +++
>   drivers/i2c/busses/i2c-aspeed.c               |   5 +-
>   6 files changed, 941 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 drivers/char/ipmi/ssif_bmc.h
>