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From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 3/6] ARM Realview PCIX map include file changes
Date: Wed, 22 Dec 2010 16:33:20 +0100	[thread overview]
Message-ID: <201012221633.20748.arnd@arndb.de> (raw)
In-Reply-To: <20101222140409.29725.82642.stgit@e102602-lin.cambridge.arm.com>

On Wednesday 22 December 2010 15:04:09 Colin Tuckley wrote:

> #define REALVIEW_PB11MP_PCI_IO_SIZE            0x1000          /* 4 Kb */

Is the I/O space really just 4 kb? This may easily cause problems,
because the first 4 kb of I/O space are usually reserved for PCI-ISA
bridges and the like. At least the public documentation for PB-X
describes a 64 kb space, which is also what everyone else has.

> +static inline unsigned int pcibios_min_io(void)
> +{
> +       if (machine_is_realview_pb11mp() || machine_is_realview_pba8() ||
> +           machine_is_realview_pbx())
> +               return REALVIEW_PB_PCI_IO_BASE;
> +       else
> +               return 0;
> +}
...
> +
>  #define IO_SPACE_LIMIT 0xffffffff
>  
> -#define __io(a)                __typesafe_io(a)
> +static inline void __iomem *__io(unsigned long addr)
> +{
> +#ifdef CONFIG_PCI
> +       /* check for PCI I/O space */
> +       if (addr >= REALVIEW_PB_PCI_IO_BASE && addr <= REALVIEW_PB_PCI_IO_LIMIT)
> +               return (void __iomem *)((addr - REALVIEW_PB_PCI_IO_BASE) + REALVIEW_PCI_IO_VBASE);
> +       else
> +               return (void __iomem *)addr;
> +#else
> +       return (void __iomem *)addr;
> +#endif
> +}

The I/O space handling still looks really wrong. Why not simply do this:

#define PCIBIOS_MIN_IO 0x1000  /* skip the first 4kb */
#define IO_SPACE_LIMIT 0xffff  /* regular 64 kb I/O space */
#define __io(a) (REALVIEW_PCI_IO_VBASE + (a & IO_SPACE_LIMIT)

If you start the I/O space at REALVIEW_PB_PCI_IO_BASE instead of 0x1000
or 0, you get into all sorts of trouble, e.g. when using /dev/ioport.

	Arnd

  reply	other threads:[~2010-12-22 15:33 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-22 14:03 [PATCH 0/6] Series short description Colin Tuckley
2010-12-22 14:03 ` [PATCH 1/6] ARM: enable bridges in pci_common_init Colin Tuckley
2010-12-22 14:04 ` [PATCH 2/6] Realview PCIX support - add main support module code Colin Tuckley
2011-01-19 13:00   ` Russell King - ARM Linux
2010-12-22 14:04 ` [PATCH 3/6] ARM Realview PCIX map include file changes Colin Tuckley
2010-12-22 15:33   ` Arnd Bergmann [this message]
2010-12-22 16:12     ` Colin Tuckley
2010-12-22 16:48     ` Arnd Bergmann
2010-12-22 14:04 ` [PATCH 4/6] ARM Realview PCIX IRQ " Colin Tuckley
2010-12-22 14:04 ` [PATCH 5/6] ARM Realview PCIX board " Colin Tuckley
2010-12-22 14:04 ` [PATCH 6/6] ARM Realview PCIX build " Colin Tuckley
  -- strict thread matches above, loose matches on Subject: below --
2010-10-20 13:02 [PATCH 0/6] Add PCI support for ARM RealView boards Colin Tuckley
2010-10-20 13:03 ` [PATCH 3/6] ARM Realview PCIX map include file changes Colin Tuckley
2010-10-20 21:28   ` Arnd Bergmann

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