[PATCH v4 1/4] tpm: add buf_size parameter in the .send callback

[Stefano Garzarella]

On Sat, May 10, 2025 at 10:44:38AM +0300, Jarkko Sakkinen wrote:
>On Fri, May 09, 2025 at 10:57:10AM +0200, Stefano Garzarella wrote:
>> From: Stefano Garzarella <sgarzare at redhat.com>
>>
>> Add a new `buf_size` parameter to the `.send` callback in `tpm_class_ops`.
>> This parameter will allow drivers to differentiate between the actual
>> command length to send and the total buffer size. Currently `buf_now` is
>> not used, but it will be used to implement devices with synchronous send()
>> to send the command and receive the response on the same buffer.
>>
>> Also rename the previous parameter `len` to `cmd_len` in the declaration
>> to make it clear that it contains the length in bytes of the command
>> stored in the buffer. The semantics don't change and it can be used as
>> before by drivers. This is an optimization since the drivers could get it
>> from the header, but let's avoid duplicating code.
>>
>> While we are here, resolve a checkpatch warning:
>>   WARNING: Unnecessary space before function pointer arguments
>>   #66: FILE: include/linux/tpm.h:90:
>>   +	int (*send) (struct tpm_chip *chip, u8 *buf, size_t cmd_len,
>>
>> Suggested-by: Jarkko Sakkinen <jarkko at kernel.org>
>> Signed-off-by: Stefano Garzarella <sgarzare at redhat.com>
>> ---
>> v4:
>> - rework the commit description [Jarkko]
>> ---
>>  include/linux/tpm.h                  | 3 ++-
>>  drivers/char/tpm/st33zp24/st33zp24.c | 2 +-
>>  drivers/char/tpm/tpm-interface.c     | 2 +-
>>  drivers/char/tpm/tpm_atmel.c         | 3 ++-
>>  drivers/char/tpm/tpm_crb.c           | 2 +-
>>  drivers/char/tpm/tpm_ftpm_tee.c      | 4 +++-
>>  drivers/char/tpm/tpm_i2c_atmel.c     | 3 ++-
>>  drivers/char/tpm/tpm_i2c_infineon.c  | 3 ++-
>>  drivers/char/tpm/tpm_i2c_nuvoton.c   | 3 ++-
>>  drivers/char/tpm/tpm_ibmvtpm.c       | 6 ++++--
>>  drivers/char/tpm/tpm_infineon.c      | 3 ++-
>>  drivers/char/tpm/tpm_nsc.c           | 3 ++-
>>  drivers/char/tpm/tpm_svsm.c          | 3 ++-
>>  drivers/char/tpm/tpm_tis_core.c      | 3 ++-
>>  drivers/char/tpm/tpm_tis_i2c_cr50.c  | 6 ++++--
>>  drivers/char/tpm/tpm_vtpm_proxy.c    | 4 +++-
>>  drivers/char/tpm/xen-tpmfront.c      | 3 ++-
>>  17 files changed, 37 insertions(+), 19 deletions(-)
>>
>> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
>> index 9ac9768cc8f7..7ac390ec89ce 100644
>> --- a/include/linux/tpm.h
>> +++ b/include/linux/tpm.h
>> @@ -87,7 +87,8 @@ struct tpm_class_ops {
>>  	const u8 req_complete_val;
>>  	bool (*req_canceled)(struct tpm_chip *chip, u8 status);
>>  	int (*recv) (struct tpm_chip *chip, u8 *buf, size_t len);
>> -	int (*send) (struct tpm_chip *chip, u8 *buf, size_t len);
>> +	int (*send)(struct tpm_chip *chip, u8 *buf, size_t cmd_len,
>> +		    size_t buf_size);
>
>I'm sorry but now that I look at this, just for the sake of consistency:
>
>	int (*send)(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
>		    size_t cmd_len);
>
>I.e. match the order and parameter names from tpm_try_transmit().

Ah, I see, makes sense, I'll update and send v5.

Thanks,
Stefano