Re: [PATCH RFC 1/2] m68k: io_mm.h: conditionalize ISA address translation on Atari

[Finn Thain <fthain@linux-m68k.org>]

On Sun, 6 Jun 2021, Michael Schmitz wrote:

> 
> This patch to io_mm.h (on top of my current patch), plus setting isa_type to
> ISA_TPYE_AG100 using a module parameter, should do the trick:
> 
> diff --git a/arch/m68k/include/asm/io_mm.h b/arch/m68k/include/asm/io_mm.h
> index f6b487b..6f79a5e 100644
> --- a/arch/m68k/include/asm/io_mm.h
> +++ b/arch/m68k/include/asm/io_mm.h
> @@ -102,6 +102,11 @@
>  #define ISA_TYPE_AG   (2)
>  #define ISA_TYPE_ENEC (3)
> 
> +#if defined(CONFIG_AMIGA_PCMCIA_100)
> +#define ISA_TYPE_AG100 (4)     /* for 100 MBit APNE card */

IMHO this would be simpler if that #define was unconditional like the 
others.

> +#define MULTI_ISA 1

Hmm...

> +#endif
> +
>  #if defined(CONFIG_Q40) && !defined(MULTI_ISA)
>  #define ISA_TYPE ISA_TYPE_Q40
>  #define ISA_SEX  0
> @@ -135,6 +140,9 @@ static inline u8 __iomem *isa_itb(unsigned long addr)
>  #ifdef CONFIG_Q40
>      case ISA_TYPE_Q40: return (u8 __iomem *)Q40_ISA_IO_B(addr);
>  #endif
> +#if defined(CONFIG_AMIGA_PCMCIA_100)
> +    case ISA_TYPE_AG100: fallthrough;
> +#endif

I wonder whether that 'fallthrough' is needed. One would hope not...

>  #ifdef CONFIG_AMIGA_PCMCIA
>      case ISA_TYPE_AG: return (u8 __iomem *)AG_ISA_IO_B(addr);
>  #endif
> @@ -153,6 +161,9 @@ static inline u16 __iomem *isa_itw(unsigned long addr)
>  #ifdef CONFIG_Q40
>      case ISA_TYPE_Q40: return (u16 __iomem *)Q40_ISA_IO_W(addr);
>  #endif
> +#if defined(CONFIG_AMIGA_PCMCIA_100)
> +    case ISA_TYPE_AG100: fallthrough;
> +#endif
>  #ifdef CONFIG_AMIGA_PCMCIA
>      case ISA_TYPE_AG: return (u16 __iomem *)AG_ISA_IO_W(addr);
>  #endif
> @@ -168,6 +179,9 @@ static inline u32 __iomem *isa_itl(unsigned long addr)
>  {
>    switch(ISA_TYPE)
>      {
> +#if defined(CONFIG_AMIGA_PCMCIA_100)
> +    case ISA_TYPE_AG100: fallthrough;
> +#endif
>  #ifdef CONFIG_AMIGA_PCMCIA
>      case ISA_TYPE_AG: return (u32 __iomem *)AG_ISA_IO_W(addr);
>  #endif
> @@ -181,6 +195,9 @@ static inline u8 __iomem *isa_mtb(unsigned long addr)
>  #ifdef CONFIG_Q40
>      case ISA_TYPE_Q40: return (u8 __iomem *)Q40_ISA_MEM_B(addr);
>  #endif
> +#if defined(CONFIG_AMIGA_PCMCIA_100)
> +    case ISA_TYPE_AG100: fallthrough;
> +#endif
>  #ifdef CONFIG_AMIGA_PCMCIA
>      case ISA_TYPE_AG: return (u8 __iomem *)addr;
>  #endif
> @@ -199,6 +216,9 @@ static inline u16 __iomem *isa_mtw(unsigned long addr)
>  #ifdef CONFIG_Q40
>      case ISA_TYPE_Q40: return (u16 __iomem *)Q40_ISA_MEM_W(addr);
>  #endif
> +#if defined(CONFIG_AMIGA_PCMCIA_100)
> +    case ISA_TYPE_AG100: fallthrough;
> +#endif
>  #ifdef CONFIG_AMIGA_PCMCIA
>      case ISA_TYPE_AG: return (u16 __iomem *)addr;
>  #endif
> @@ -219,6 +239,11 @@ static inline u16 __iomem *isa_mtw(unsigned long addr)
>  #define isa_outw(val,port) (ISA_SEX ? out_be16(isa_itw(port),(val)) :
> out_le16(isa_itw(port),(val)))
>  #define isa_outl(val,port) (ISA_SEX ? out_be32(isa_itl(port),(val)) :
> out_le32(isa_itl(port),(val)))
> 
> +#if defined(CONFIG_AMIGA_PCMCIA_100)
> +#undef isa_inb
> +#define isa_inb(port)      ((ISA_TYPE == ISA_TYPE_AG100) ? ((port) & 1 ?
> isa_inw((port) - 1) & 0xff : isa_inw(port) >> 8) : in_8(isa_itb(port))
> +#endif
> +

Would (port & ~1) be faster than (port - 1) here?

Also, I don't think you need '#if defined' here. When 
!defined(CONFIG_AMIGA_PCMCIA_100), I think ISA_TYPE should be a 
compile-time constant 0, and the dead code will get tossed out anyway.

>  #define isa_readb(p)       in_8(isa_mtb((unsigned long)(p)))
>  #define isa_readw(p)       \
>         (ISA_SEX ? in_be16(isa_mtw((unsigned long)(p))) \
> 
> (linebreak-mangled, sorry).
> 
> The card reset patch hunk from Alex' patch can probably go into the APNE
> driver regardless?
> 
> It's been quite a while - can you still try and build/test this change, Alex?

Note that isa_type is never assigned to ISA_TYPE_AG100 in 
arch/m68k/kernel/setup_mm.c which means (IIUC) this patch won't take 
effect with MULTI_ISA == 1.