Re: [PATCH v4 2/2] ata: pata_falcon: add data_swab option to byte-swap disk data

[Sergey Shtylyov <s.shtylyov@omp.ru>]

On 8/23/23 1:13 AM, Michael Schmitz wrote:

> Some users of pata_falcon on Q40 have IDE disks in default
> IDE little endian byte order, whereas legacy disks use
> host-native big-endian byte order as on the Atari Falcon.
> 
> Add module parameter 'data_swab' to allow connecting drives
> with non-native data byte order. Drives selected by the
> data_swap bit mask will have their user data byte-swapped to
> host byte order, i.e. 'pata_falcon.data_swab=2' will byte-swap
> all user data on drive B, leaving data on drive A in native
> byte order. On Q40, drives on a second IDE interface may be
> added to the bit mask as bits 2 and 3.
> 
> Default setting is no byte swapping, i.e. compatibility with
> the native Falcon or Q40 operating system disk format.
> 
> Cc: William R Sowerbutts <will@sowerbutts.com>
> Cc: Finn Thain <fthain@linux-m68k.org>
> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> Tested-by: William R Sowerbutts <will@sowerbutts.com>
> Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>

Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>

[...]

> diff --git a/drivers/ata/pata_falcon.c b/drivers/ata/pata_falcon.c
> index 3841ea200bcb..7cf15bd9764a 100644
> --- a/drivers/ata/pata_falcon.c
> +++ b/drivers/ata/pata_falcon.c
[...]
> @@ -194,6 +199,9 @@ static int __init pata_falcon_init_one(struct platform_device *pdev)
>  	ata_port_desc(ap, "cmd %px ctl %px data %pa",
>  		      base, ctl_base, &ap->ioaddr.data_addr);
>  
> +	ap->private_data = (void *)(uintptr_t)(pdev->id > 0 ?
> +		pata_falcon_swap_mask >> 2 : pata_falcon_swap_mask);

   How about:

	ap->private_data = (void *)(uintptr_t)(pata_falcon_swap_mask >>
			   (pdev->id > 0 ? 2 : 0));

[...]

MBR, Sergey