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

Finn Thain
2021-06-03T08:23:08Z

On Wed, 2 Jun 2021, Michael Schmitz wrote:

> Current io_mm.h uses address translation and ROM port IO primitives when
> port addresses are below 1024, and raw untranslated MMIO IO primitives
> else when CONFIG_ATARI_ROM_ISA is set. This is done regardless of the
> m68k machine type a multi-platform kernel runs on. As a consequence,
> the Q40 IDE driver in multiplatform kernels cannot work.
> Conversely, the Atari IDE driver uses wrong address translation if a
> multiplatform Q40 and Atari kernel does _not_ set CONFIG_ATARI_ROM_ISA.
>
> Replace MMIO by ISA IO primitives for addresses > 1024 (if isa_type
> is ISA_TYPE_ENEC), and change the ISA address translation used for
> Atari to a no-op for those addresses.
>
> Switch readb()/writeb() and readw()/writew() to their ISA equivalents
> also. Change the address translation functions to return the identity
> translation if CONFIG_ATARI_ROM_ISA is not defined, and set MULTI_ISA
> for kernels where Q40 and Atari are both configured so this can actually
> work (isa_type set to Q40 at compile time else).
>

Thanks, this does fix the problem I had with CONFIG_ATARI && CONFIG_ISA.

> Signed-off-by: Michael Schmity <schmitzmic@gmail.com>

Checkpatch points out a typo here.

Also, I think this should get a 'Fixes' tag so it will be backported.

> ---
> arch/m68k/include/asm/io_mm.h | 64 +++++++++++++++++++++++++++----------------
> 1 file changed, 40 insertions(+), 24 deletions(-)
>
> diff --git a/arch/m68k/include/asm/io_mm.h b/arch/m68k/include/asm/io_mm.h
> index d41fa48..2275e54 100644
> --- a/arch/m68k/include/asm/io_mm.h
> +++ b/arch/m68k/include/asm/io_mm.h
> @@ -52,7 +52,11 @@
> #define Q40_ISA_MEM_B(madr) (q40_isa_mem_base+1+4*((unsigned long)(madr)))
> #define Q40_ISA_MEM_W(madr) (q40_isa_mem_base+ 4*((unsigned long)(madr)))
>
> +#ifdef CONFIG_ATARI
> +#define MULTI_ISA 1
> +#else
> #define MULTI_ISA 0
> +#endif /* Atari */
> #endif /* Q40 */
>

I have to wonder whether there is a nice simple definition for MULTI_ISA.
Such a definition would make this file a lot more easily understood. Maybe
that flag could be implemented as a Kconfig symbol. I guess that's out of
scope though.

> #ifdef CONFIG_AMIGA_PCMCIA
> @@ -135,9 +139,12 @@ static inline u8 __iomem *isa_itb(unsigned long addr)
> case ISA_TYPE_AG: return (u8 __iomem *)AG_ISA_IO_B(addr);
> #endif
> #ifdef CONFIG_ATARI_ROM_ISA
> - case ISA_TYPE_ENEC: return (u8 __iomem *)ENEC_ISA_IO_B(addr);
> + case ISA_TYPE_ENEC: if (addr < 1024)
> + return (u8 __iomem *)ENEC_ISA_IO_B(addr);
> + else
> + return (u8 __iomem *)(addr);

There is some trailing whitespace added here that 'git am' complains
about.

Also, I think a 'fallthrough' statement would be better than adding a new
else branch that duplicates the new default case below.

> #endif
> - default: return NULL; /* avoid warnings, just in case */
> + default: return (u8 __iomem *)(addr); /* avoid warnings, just in case */
> }
> }
> static inline u16 __iomem *isa_itw(unsigned long addr)
> @@ -151,9 +158,12 @@ static inline u16 __iomem *isa_itw(unsigned long addr)
> case ISA_TYPE_AG: return (u16 __iomem *)AG_ISA_IO_W(addr);
> #endif
> #ifdef CONFIG_ATARI_ROM_ISA
> - case ISA_TYPE_ENEC: return (u16 __iomem *)ENEC_ISA_IO_W(addr);
> + case ISA_TYPE_ENEC: if (addr < 1024)
> + return (u16 __iomem *)ENEC_ISA_IO_W(addr);
> + else
> + return (u16 __iomem *)(addr);
> #endif
> - default: return NULL; /* avoid warnings, just in case */
> + default: return (u16 __iomem *)(addr); /* avoid warnings, just in case */

Same here.

> }
> }
> static inline u32 __iomem *isa_itl(unsigned long addr)
> @@ -177,9 +187,12 @@ static inline u8 __iomem *isa_mtb(unsigned long addr)
> case ISA_TYPE_AG: return (u8 __iomem *)addr;
> #endif
> #ifdef CONFIG_ATARI_ROM_ISA
> - case ISA_TYPE_ENEC: return (u8 __iomem *)ENEC_ISA_MEM_B(addr);
> + case ISA_TYPE_ENEC: if (addr < 1024)
> + return (u8 __iomem *)ENEC_ISA_MEM_B(addr);
> + else
> + return (u8 __iomem *)(addr);
> #endif
> - default: return NULL; /* avoid warnings, just in case */
> + default: return (u8 __iomem *)(addr); /* avoid warnings, just in case */

And here.

> }
> }
> static inline u16 __iomem *isa_mtw(unsigned long addr)
> @@ -193,9 +206,12 @@ static inline u16 __iomem *isa_mtw(unsigned long addr)
> case ISA_TYPE_AG: return (u16 __iomem *)addr;
> #endif
> #ifdef CONFIG_ATARI_ROM_ISA
> - case ISA_TYPE_ENEC: return (u16 __iomem *)ENEC_ISA_MEM_W(addr);
> + case ISA_TYPE_ENEC: if (addr < 1024)
> + return (u16 __iomem *)ENEC_ISA_MEM_W(addr);
> + else
> + return (u16 __iomem *)(addr);
> #endif
> - default: return NULL; /* avoid warnings, just in case */
> + default: return (u16 __iomem *)(addr); /* avoid warnings, just in case */

And here.

> }
> }
>
> @@ -344,31 +360,31 @@ static inline void isa_delay(void)
> * ROM port ISA and everything else regular ISA for IDE. read,write defined
> * below.
> */
> -#define inb(port) ((port) < 1024 ? isa_rom_inb(port) : in_8(port))
> -#define inb_p(port) ((port) < 1024 ? isa_rom_inb_p(port) : in_8(port))
> -#define inw(port) ((port) < 1024 ? isa_rom_inw(port) : in_le16(port))
> -#define inw_p(port) ((port) < 1024 ? isa_rom_inw_p(port) : in_le16(port))
> +#define inb(port) (((port) < 1024 && ISA_TYPE == ISA_TYPE_ENEC) ? isa_rom_inb(port) : isa_inb(port))
> +#define inb_p(port) (((port) < 1024 && ISA_TYPE == ISA_TYPE_ENEC) ? isa_rom_inb_p(port) : isa_inb_p(port))
> +#define inw(port) (((port) < 1024 && ISA_TYPE == ISA_TYPE_ENEC) ? isa_rom_inw(port) : isa_inw(port))
> +#define inw_p(port) (((port) < 1024 && ISA_TYPE == ISA_TYPE_ENEC) ? isa_rom_inw_p(port) : isa_inw_p(port))
> #define inl isa_inl
> #define inl_p isa_inl_p
>
> -#define outb(val, port) ((port) < 1024 ? isa_rom_outb((val), (port)) : out_8((port), (val)))
> -#define outb_p(val, port) ((port) < 1024 ? isa_rom_outb_p((val), (port)) : out_8((port), (val)))
> -#define outw(val, port) ((port) < 1024 ? isa_rom_outw((val), (port)) : out_le16((port), (val)))
> -#define outw_p(val, port) ((port) < 1024 ? isa_rom_outw_p((val), (port)) : out_le16((port), (val)))
> +#define outb(val, port) (((port) < 1024 && ISA_TYPE == ISA_TYPE_ENEC) ? isa_rom_outb((val), (port)) : isa_outb((val), (port)))
> +#define outb_p(val, port) (((port) < 1024 && ISA_TYPE == ISA_TYPE_ENEC) ? isa_rom_outb_p((val), (port)) : isa_outb_p((val), (port)))
> +#define outw(val, port) (((port) < 1024 && ISA_TYPE == ISA_TYPE_ENEC) ? isa_rom_outw((val), (port)) : isa_outw((val), (port)))
> +#define outw_p(val, port) (((port) < 1024 && ISA_TYPE == ISA_TYPE_ENEC) ? isa_rom_outw_p((val), (port)) : isa_outw_p((val), (port)))
> #define outl isa_outl
> #define outl_p isa_outl_p
>
> -#define insb(port, buf, nr) ((port) < 1024 ? isa_rom_insb((port), (buf), (nr)) : isa_insb((port), (buf), (nr)))
> -#define insw(port, buf, nr) ((port) < 1024 ? isa_rom_insw((port), (buf), (nr)) : isa_insw((port), (buf), (nr)))
> +#define insb(port, buf, nr) (((port) < 1024 && ISA_TYPE == ISA_TYPE_ENEC) ? isa_rom_insb((port), (buf), (nr)) : isa_insb((port), (buf), (nr)))
> +#define insw(port, buf, nr) (((port) < 1024 && ISA_TYPE == ISA_TYPE_ENEC) ? isa_rom_insw((port), (buf), (nr)) : isa_insw((port), (buf), (nr)))
> #define insl isa_insl
> -#define outsb(port, buf, nr) ((port) < 1024 ? isa_rom_outsb((port), (buf), (nr)) : isa_outsb((port), (buf), (nr)))
> -#define outsw(port, buf, nr) ((port) < 1024 ? isa_rom_outsw((port), (buf), (nr)) : isa_outsw((port), (buf), (nr)))
> +#define outsb(port, buf, nr) (((port) < 1024 && ISA_TYPE == ISA_TYPE_ENEC) ? isa_rom_outsb((port), (buf), (nr)) : isa_outsb((port), (buf), (nr)))
> +#define outsw(port, buf, nr) (((port) < 1024 && ISA_TYPE == ISA_TYPE_ENEC) ? isa_rom_outsw((port), (buf), (nr)) : isa_outsw((port), (buf), (nr)))
> #define outsl isa_outsl
>
> -#define readb(addr) in_8(addr)
> -#define writeb(val, addr) out_8((addr), (val))
> -#define readw(addr) in_le16(addr)
> -#define writew(val, addr) out_le16((addr), (val))
> +#define readb isa_readb
> +#define readw isa_readw
> +#define writeb isa_writeb
> +#define writew isa_writew
> #endif /* CONFIG_ATARI_ROM_ISA */
>
> #define readl(addr) in_le32(addr)
>