Re: [Qemu-devel] [PATCH 3/5] lsi: use enum type for s->msg_action

[Philippe Mathieu-Daudé]

On 3/5/19 12:14 AM, Philippe Mathieu-Daudé wrote:
> On 3/4/19 7:09 PM, Sven Schnelle wrote:
>> This makes the code easier to read - no functional change.
>>
>> Signed-off-by: Sven Schnelle <address@hidden>
>> ---
>>  hw/scsi/lsi53c895a.c | 27 ++++++++++++++++-----------
>>  1 file changed, 16 insertions(+), 11 deletions(-)
>>
>> diff --git a/hw/scsi/lsi53c895a.c b/hw/scsi/lsi53c895a.c
>> index fb9c6db4b2..d1eb2cf074 100644
>> --- a/hw/scsi/lsi53c895a.c
>> +++ b/hw/scsi/lsi53c895a.c
>> @@ -201,6 +201,13 @@ enum {
>>      LSI_DMA_IN_PROGRESS, /* DMA operation is in progress */
>>  };
>>  
>> +enum {
> Since someone unfamiliar with the device could add:
> 
>        LSI_MSG_ACTION_DEBUG,
> 
>> +    LSI_MSG_ACTION_COMMAND,
>> +    LSI_MSG_ACTION_DISCONNECT,
>> +    LSI_MSG_ACTION_DOUT,
>> +    LSI_MSG_ACTION_DIN,
> 
> ... it is safer to assign values when enum are not expected to change:
> 
>       LSI_MSG_ACTION_COMMAND = 0,
>       LSI_MSG_ACTION_DISCONNECT = 1,
>       LSI_MSG_ACTION_DOUT = 2,
>       LSI_MSG_ACTION_DIN = 3,
> 
> With that change:
> Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
> 
>> +};
>> +
>>  typedef struct {
>>      /*< private >*/
>>      PCIDevice parent_obj;
>> @@ -214,8 +221,6 @@ typedef struct {
>>  
>>      int carry; /* ??? Should this be an a visible register somewhere?  */
>>      int status;
>> -    /* Action to take at the end of a MSG IN phase.
>> -       0 = COMMAND, 1 = disconnect, 2 = DATA OUT, 3 = DATA IN.  */
>>      int msg_action;

I'd also declare 'enum msg_action' here (same comments as patch 2 of
this series).
Regardless the Reviewed-by tag stands.

>>      int msg_len;
>>      uint8_t msg[LSI_MAX_MSGIN_LEN];
>> @@ -323,7 +328,7 @@ static void lsi_soft_reset(LSIState *s)
>>      trace_lsi_reset();
>>      s->carry = 0;
>>  
>> -    s->msg_action = 0;
>> +    s->msg_action = LSI_MSG_ACTION_COMMAND;
>>      s->msg_len = 0;
>>      s->waiting = LSI_NOWAIT;
>>      s->dsa = 0;
>> @@ -686,7 +691,7 @@ static void lsi_reselect(LSIState *s, lsi_request *p)
>>      trace_lsi_reselect(id);
>>      s->scntl1 |= LSI_SCNTL1_CON;
>>      lsi_set_phase(s, PHASE_MI);
>> -    s->msg_action = p->out ? 2 : 3;
>> +    s->msg_action = p->out ? LSI_MSG_ACTION_DOUT : LSI_MSG_ACTION_DIN;
>>      s->current->dma_len = p->pending;
>>      lsi_add_msg_byte(s, 0x80);
>>      if (s->current->tag & LSI_TAG_VALID) {
>> @@ -857,7 +862,7 @@ static void lsi_do_command(LSIState *s)
>>              lsi_add_msg_byte(s, 4); /* DISCONNECT */
>>              /* wait data */
>>              lsi_set_phase(s, PHASE_MI);
>> -            s->msg_action = 1;
>> +            s->msg_action = LSI_MSG_ACTION_DISCONNECT;
>>              lsi_queue_command(s);
>>          } else {
>>              /* wait command complete */
>> @@ -878,7 +883,7 @@ static void lsi_do_status(LSIState *s)
>>      s->sfbr = status;
>>      pci_dma_write(PCI_DEVICE(s), s->dnad, &status, 1);
>>      lsi_set_phase(s, PHASE_MI);
>> -    s->msg_action = 1;
>> +    s->msg_action = LSI_MSG_ACTION_DISCONNECT;
>>      lsi_add_msg_byte(s, 0); /* COMMAND COMPLETE */
>>  }
>>  
>> @@ -901,16 +906,16 @@ static void lsi_do_msgin(LSIState *s)
>>          /* ??? Check if ATN (not yet implemented) is asserted and maybe
>>             switch to PHASE_MO.  */
>>          switch (s->msg_action) {
>> -        case 0:
>> +        case LSI_MSG_ACTION_COMMAND:
>>              lsi_set_phase(s, PHASE_CMD);
>>              break;
>> -        case 1:
>> +        case LSI_MSG_ACTION_DISCONNECT:
>>              lsi_disconnect(s);
>>              break;
>> -        case 2:
>> +        case LSI_MSG_ACTION_DOUT:
>>              lsi_set_phase(s, PHASE_DO);
>>              break;
>> -        case 3:
>> +        case LSI_MSG_ACTION_DIN:
>>              lsi_set_phase(s, PHASE_DI);
>>              break;
>>          default:
>> @@ -1062,7 +1067,7 @@ bad:
>>      qemu_log_mask(LOG_UNIMP, "Unimplemented message 0x%02x\n", msg);
>>      lsi_set_phase(s, PHASE_MI);
>>      lsi_add_msg_byte(s, 7); /* MESSAGE REJECT */
>> -    s->msg_action = 0;
>> +    s->msg_action = LSI_MSG_ACTION_COMMAND;
>>  }
>>  
>>  #define LSI_BUF_SIZE 4096
>>