Re: [PATCH 1/3] m68k/q40: fix IO base selection for Q40 in pata_falcon.c

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

Hello!

On 8/18/23 1:12 AM, Michael Schmitz wrote:

> With commit 44b1fbc0f5f3 ("m68k/q40: Replace q40ide driver
> with pata_falcon and falconide"), the Q40 IDE driver was
> replaced by pata_falcon.c.
> 
> Both IO and memory resources were defined for the Q40 IDE
> platform device, but definition of the IDE register addresses
> was modeled after the Falcon case, both in use of the memory
> resources and in including register scale and byte vs. word
> offset in the address.
> 
> This was correct for the Falcon case, which does not apply
> any address translation to the register addresses. In the
> Q40 case, all of device base address, byte access offset
> and register scaling is included in the platform specific
> ISA access translation (in asm/mm_io.h).
> 
> As a consequence, such address translation gets applied
> twice, and register addresses are mangled.
> 
> Use the device base address from the platform IO resource,
> and use standard register offsets from that base in order
> to calculate register addresses (the IO address translation
> will then apply the correct ISA window base and scaling).
> 
> Encode PIO_OFFSET into IO port addresses for all registers
> except the data transfer register. Encode the MMIO offset
> there (pata_falcon_data_xfer() directly uses raw IO with
> no address translation).
> 
> Reported-by: William R Sowerbutts <will@sowerbutts.com>
> Closes: https://lore.kernel.org/r/CAMuHMdUU62jjunJh9cqSqHT87B0H0A4udOOPs=WN7WZKpcagVA@mail.gmail.com
> Link: https://lore.kernel.org/r/CAMuHMdUU62jjunJh9cqSqHT87B0H0A4udOOPs=WN7WZKpcagVA@mail.gmail.com
> Fixes: 44b1fbc0f5f3 ("m68k/q40: Replace q40ide driver with pata_falcon and falconide")
> Cc: <stable@vger.kernel.org> # 5.14
> Cc: Finn Thain <fthain@linux-m68k.org>
> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> 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 996516e64f13..346259e3bbc8 100644
> --- a/drivers/ata/pata_falcon.c
> +++ b/drivers/ata/pata_falcon.c
> @@ -123,8 +123,8 @@ static int __init pata_falcon_init_one(struct platform_device *pdev)
>  	struct resource *base_res, *ctl_res, *irq_res;
>  	struct ata_host *host;
>  	struct ata_port *ap;
> -	void __iomem *base;
> -	int irq = 0;
> +	void __iomem *base, *ctl_base;
> +	int irq = 0, io_offset = 1, reg_scale = 4;

   Maybe reg_step?

[...]

MBR, Sergey