Re: [PATCH v3 1/3] libata: Populate host-to-device FIS "auxiliary" field

[Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>]

On 08/09/2013 06:17 PM, Sergei Shtylyov wrote:

>> From: Marc Carino <marc.ceeeee@gmail.com>

>> SATA 3.1 added an "auxiliary" field to the host-to-device FIS.

>> Since there is no analog between the new field and the ATA
>> taskfile, a new element was added to 'struct ata_queued_cmd."

>> Signed-off-by: Marc Carino <marc.ceeeee@gmail.com>

> [...]

>> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
>> index c24354d..9d02c47 100644
>> --- a/drivers/ata/libata-core.c
>> +++ b/drivers/ata/libata-core.c
>> @@ -532,6 +532,34 @@ int atapi_cmd_type(u8 opcode)
>>   }
>>
>>   /**
>> + *    ata_qc_to_fis - Convert struct ata_queued_cmd to SATA FIS structure
>> + *    @qc: struct ata_queued_cmd to convert
>> + *    @pmp: Port multiplier port
>> + *    @is_cmd: This FIS is for command
>> + *    @fis: Buffer into which data will output
>> + *
>> + *    Converts a struct ata_queued_cmd to a Serial ATA
>> + *    FIS structure (Register - Host to Device).
>> + *
>> + *    Beginning with SATA 3.1, the ATA taskfile does not completely describe
>> + *    all of the fields in a host-to-device FIS. More specifically, the
>> + *    'auxiliary' field has no ATA taskfile analog, and thus requires us
>> + *    to populate the FIS via the ata_queued_cmd structure.
>> + *
>> + *    LOCKING:
>> + *    Inherited from caller.
>> + */
>> +void ata_qc_to_fis(const struct ata_queued_cmd *qc, u8 pmp, int is_cmd, u8
>> *fis)
>> +{
>> +    ata_tf_to_fis(&qc->tf, pmp, is_cmd, fis);
>> +
>> +    fis[16] = qc->auxiliary & 0xff;
>> +    fis[17] = (qc->auxiliary >> 8) & 0xff;
>> +    fis[18] = (qc->auxiliary >> 16) & 0xff;
>> +    fis[19] = (qc->auxiliary >> 24) & 0xff;
>> +}
>> +
>> +/**
>>    *    ata_tf_to_fis - Convert ATA taskfile to SATA FIS structure
>>    *    @tf: Taskfile to convert
>>    *    @pmp: Port multiplier port
>> @@ -6877,6 +6905,7 @@ EXPORT_SYMBOL_GPL(ata_sg_init);
>>   EXPORT_SYMBOL_GPL(ata_qc_complete);
>>   EXPORT_SYMBOL_GPL(ata_qc_complete_multiple);
>>   EXPORT_SYMBOL_GPL(atapi_cmd_type);
>> +EXPORT_SYMBOL_GPL(ata_qc_to_fis);
>>   EXPORT_SYMBOL_GPL(ata_tf_to_fis);

>     I think we should now unexport this function and make it static since it
> would be no longer valid to call it from the drivers...

    I was somewhat rash in this conclusion: drivers use this function not only 
to issue commands but also to fake D2H FIS and not only that...

WBR, Sergei