Re: [PATCH RFC v3 2/2] m68k/q40: add data_swab option for pata_falcon to byte-swap disk data

[Michael Schmitz <schmitzmic@gmail.com>]

Hi Geert,

On 18/08/23 07:21, Michael Schmitz wrote:
>
>>>> +             priv->swap_mask = pata_falcon_swap_mask;
>> priv->swap_mask = pata_falcon_swap_mask >> (2 * pdev->id);
>
> The Atari platform driver data is registered with pdev->id=-1. That'll 
> break here.
Confirmed.
>
> (Not sure why that choice of pdev->id, and whether it can be changed 
> to 0 easily)
Seems to work OK with ID set to 0, so I'll simplify that as you suggest.

Cheers,

     Michael


> Cheers,
>
>     Michael
>
>
>>
>>> --- a/drivers/ata/pata_falcon.c
>>> +++ b/drivers/ata/pata_falcon.c
>>> @@ -33,6 +33,11 @@
>>>   #define DRV_NAME "pata_falcon"
>>>   #define DRV_VERSION "0.1.0"
>>>
>>> +static int pata_falcon_data_swab;
>>> +
>>> +module_param_named(data_swab, pata_falcon_data_swab, int, 0444);
>>> +MODULE_PARM_DESC(data_swab, "Data byte swap enable/disable bitmap 
>>> (0x1==drive1, 0x2==drive2, 0x4==drive3, 0x8==drive4, default: 0)");
>>> +
>>>   static const struct scsi_host_template pata_falcon_sht = {
>>>          ATA_PIO_SHT(DRV_NAME),
>>>   };
>>> @@ -50,7 +55,7 @@ static unsigned int pata_falcon_data_xfer(struct 
>>> ata_queued_cmd *qc,
>>>
>>>          if (dev->class == ATA_DEV_ATA && cmd &&
>>>              !blk_rq_is_passthrough(scsi_cmd_to_rq(cmd)))
>>> -               swap = 0;
>>> +               swap = (int)ap->private_data & BIT(dev->devno);
>> "(uintptr_t)", to make it 64-bit clean.
>>
>> Yeah, we don't support COMPILE_TEST=y yet for PATA_FALCON.
>> BTW, looks like we don't need any of the following anymore:
>>
>>      #include <asm/setup.h>
>>      #include <asm/atarihw.h>
>>      #include <asm/atariints.h>
>>      #include <asm/atari_stdma.h>
>>
>> That leaves us with <asm/ide.h>, (which does not exist on most
>> architectures, and seems to be mostly obsolete), for the (indirectly
>> included) definitions of raw_{in,out}sw_{,swapw}()....
>>
>>>          /* Transfer multiple of 2 bytes */
>>>          if (rw == READ) {
>>> @@ -199,6 +204,8 @@ static int __init pata_falcon_init_one(struct 
>>> platform_device *pdev)
>>>          ap->ioaddr.altstatus_addr       = ctl_base + io_offset;
>>>          ap->ioaddr.ctl_addr             = ctl_base + io_offset;
>>>
>>> +       ap->private_data = (void *)((pata_falcon_data_swab >> (2 * 
>>> pdev->id)) & 3);
>> "(void *)(uintptr_t)", to make it 64-bit clean.
>>
>>> +
>>>          irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
>>>          if (irq_res && irq_res->start > 0) {
>>>                  irq = irq_res->start;
>> Gr{oetje,eeting}s,
>>
>>                          Geert
>>