Re: [PATCH 1/1] pata_via.c: Support VX855 and future chips whose IDE controller use 0x0571.

[Tejun Heo <tj@kernel.org>]

JosephChan@via.com.tw wrote:
>>> +	if (ap->port_no == 0 && pdev->device == 0xC409) {
>>> +		pci_read_config_dword(pdev, 0x52, &ata66);
>>> +		return (ata66 & 0x10)  ? ATA_CBL_PATA80 : 
>> ATA_CBL_PATA40;
>>> +	} else if (ap->port_no == 1 && pdev->device == 0xC409) {
>>> +		DPRINTK("C409 only has one pata channel\n");
>>> +		return ATA_CBL_PATA_UNK;
>>> +	}
>> Eh.. can you add 0xC409 entry like other controllers and put 
>> necessary restrictions there?
>>
> 
> It's a pity that we don't have corresponding registers for
> identifying the single port controller. So, we just can do this by
> checking the device ID at present.

I feel a bit confused so please correct me if I'm babbling.  Can't you
add { PCI_VDEVICE(VIA, 0xC409), FLAGS_OR_IDENTIFIER } to pci_device_id
table and use different port_info on it?  If that's too different from
how other devices are beign identified, you can just add the
corresponding logic to init_one() and use, say, via_single_port_info
there instead of doing it deep in the reset sequence.

>>>  static void via_tf_load(struct ata_port *ap, const struct 
>>> ata_taskfile *tf)  {
>>> -	struct ata_taskfile tmp_tf;
>>> +	struct ata_ioports *ioaddr = &ap->ioaddr;
>>>  
>>> -	if (ap->ctl != ap->last_ctl && !(tf->flags & 
>> ATA_TFLAG_DEVICE)) {
>>> -		tmp_tf = *tf;
>>> -		tmp_tf.flags |= ATA_TFLAG_DEVICE;
>>> -		tf = &tmp_tf;
>>> +	if (tf->ctl != ap->last_ctl) {
>>> +		iowrite8(tf->ctl, ioaddr->ctl_addr);
>>> +		iowrite8(tf->device, ioaddr->device_addr);
>>>  	}
>>> +
>>>  	ata_sff_tf_load(ap, tf);
>> Can you please explain why this change is necessary?  And if 
>> it's necessary, please put it in a separate patch.
>>
> 
> Yes,  I will separate it.

Thanks.

-- 
tejun