Hi Michael,
On Fri, Aug 25, 2023 at 3:13 AM Michael Schmitz <schmitzmic@xxxxxxxxx> 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@xxxxxxxxxxxxxx>
> Cc: Finn Thain <fthain@xxxxxxxxxxxxxx>
> Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> Tested-by: William R Sowerbutts <will@xxxxxxxxxxxxxx>
> Signed-off-by: Michael Schmitz <schmitzmic@xxxxxxxxx>
> Reviewed-by: Sergey Shtylyov <s.shtylyov@xxxxxx>
> Reviewed-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
>
> ---
>
> Changes since v4:
>
> Damien Le Moal:
> - spell out bitmask shift calculation
Thanks for the update!
Sorry to bother you again...
> --- a/drivers/ata/pata_falcon.c
> +++ b/drivers/ata/pata_falcon.c
> @@ -124,7 +129,7 @@ static int __init pata_falcon_init_one(struct platform_device *pdev)
> struct ata_host *host;
> struct ata_port *ap;
> void __iomem *base, *ctl_base;
> - int irq = 0, io_offset = 1, reg_shift = 2; /* Falcon defaults */
> + int irq = 0, io_offset = 1, reg_shift = 2, mask_shift; /* Falcon defaults */
The comment does not apply to the mask_shift variable, unless you
pre-initialize it to 0...
>
> dev_info(&pdev->dev, "Atari Falcon and Q40/Q60 PATA controller\n");
>
> @@ -194,6 +199,12 @@ static int __init pata_falcon_init_one(struct platform_device *pdev)
> ata_port_desc(ap, "cmd %px ctl %px data %px",
> base, ctl_base, ap->ioaddr.data_addr);
>
> + if (pdev->id > 0)
> + mask_shift = 2;
> + else
> + mask_shift = 0;
... and drop the else.
> + ap->private_data = (void *)(uintptr_t)(pata_falcon_swap_mask >> mask_shift);
> +
> 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
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
