Re: [PATCH v10 0/3] Add SSIF BMC driver

[Quan Nguyen]

Dear Corey,

Thank you so much for helping me with all the comments and guidelines 
you've shared though many versions.

Best regards,
- Quan

On 06/10/2022 06:53, Corey Minyard wrote:
> On Tue, Oct 04, 2022 at 04:31:03PM +0700, 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 and AST2600
>
> I have applied the two IPMI patches to the IPMI tree for 6.2.  Thanks
> for sticking with this.
>
> -corey
>
> > Discussion for v9:
> > https://lore.kernel.org/lkml/20220929080326.752907-1-quan@xxxxxxxxxxxxxxxxxxxxxx/
> >
> > v10:
> >    + Issuing RxCmdLast command for all errnos                   [Wolfram]
> >
> > 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
> >
> > --
> > 2.35.1