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Date:   Thu, 6 Oct 2022 13:42:56 +0700
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Subject: Re: [PATCH v10 0/3] Add SSIF BMC driver
Content-Language: en-CA
To:     minyard@acm.org
Cc:     Randy Dunlap <rdunlap@infradead.org>,
        Wolfram Sang <wsa@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Brendan Higgins <brendan.higgins@linux.dev>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Joel Stanley <joel@jms.id.au>,
        Andrew Jeffery <andrew@aj.id.au>,
        openipmi-developer@lists.sourceforge.net,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-i2c@vger.kernel.org, openbmc@lists.ozlabs.org,
        linux-arm-kernel@lists.infradead.org,
        linux-aspeed@lists.ozlabs.org,
        Open Source Submission <patches@amperecomputing.com>,
        Phong Vo <phong@os.amperecomputing.com>,
        thang@os.amperecomputing.com
References: <20221004093106.1653317-1-quan@os.amperecomputing.com>
 <Yz4Y4piC+e1mftLi@minyard.net>
From:   Quan Nguyen <quan@os.amperecomputing.com>
In-Reply-To: <Yz4Y4piC+e1mftLi@minyard.net>
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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@os.amperecomputing.com/
>>
>> 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
>>