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Re: xorg-server-1.5.2 doesn't work because of missing sysfs pci resource

To: Ralf Baechle <ralf@linux-mips.org>
Subject: Re: xorg-server-1.5.2 doesn't work because of missing sysfs pci resource files
From: Zhang Le <r0bertz@gentoo.org>
Date: Sun, 7 Dec 2008 00:47:06 +0800
Cc: linux-mips@linux-mips.org
In-reply-to: <20081206102030.GA9410@linux-mips.org>
Mail-followup-to: Ralf Baechle <ralf@linux-mips.org>, linux-mips@linux-mips.org
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <20081205154339.GA14327@adriano.hkcable.com.hk> <20081206102030.GA9410@linux-mips.org>
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On 10:20 Sat 06 Dec     , Ralf Baechle wrote:
> On Fri, Dec 05, 2008 at 11:43:42PM +0800, Zhang Le wrote:
> 
> > I have tried xorg-server-1.5.2 on loongson 2f recently.
> > But I found it doesn't work.
> > It's mainly because of this change:
> > http://www.x.org/wiki/PciReworkProposal
> > 
> > In short:
> > "Rather than duplicating the efforts of kernel developers, X.org needs to 
> > use the
> > interfaces provided by the kernel as much as possible."
> > 
> > I have read some code of libpciaccess, the new library utilizing kernel 
> > function
> > to access pci bus. It will try to mmap this file:
> > /sys/bus/pci/devices/0000:0x:xx.x/resource0
> > (replace x with any digit appropriate)
> > Note there is a 0 at the end of the file name. This file's permission is 
> > 600.
> > 
> > However, I found on my loongson system, there is only 
> > /sys/bus/pci/devices/0000:0x:xx.x/resource
> > Note there is no 0 at the end.
> > 
> > Then I tried to read kernel code. I found it seems that for mips linux to 
> > have
> > this file, HAVE_PCI_MMAP must be defined. However, it is currently not 
> > defined.
> > 
> > Since I am not familiar with PCI, yet.
> > So could someone please shed some light on this?
> > Why HAVE_PCI_MMAP is not defined?
> 
> Here is a quick'n'dirty solution which I've not tested beyond just
> compiling.  It should work but performance will be bad.  Either way, I'm
> interested in a test report with X.

Thanks, Ralf.
I will test it.

> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
> 
> diff --git a/arch/mips/include/asm/pci.h b/arch/mips/include/asm/pci.h
> index 5510c53..053e463 100644
> --- a/arch/mips/include/asm/pci.h
> +++ b/arch/mips/include/asm/pci.h
> @@ -79,6 +79,11 @@ static inline void pcibios_penalize_isa_irq(int irq, int 
> active)
>       /* We don't do dynamic PCI IRQ allocation */
>  }
>  
> +#define HAVE_PCI_MMAP
> +
> +extern int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct 
> *vma,
> +     enum pci_mmap_state mmap_state, int write_combine);
> +
>  /*
>   * Dynamic DMA mapping stuff.
>   * MIPS has everything mapped statically.
> diff --git a/arch/mips/pci/pci.c b/arch/mips/pci/pci.c
> index a377e9d..9233193 100644
> --- a/arch/mips/pci/pci.c
> +++ b/arch/mips/pci/pci.c
> @@ -354,6 +354,22 @@ EXPORT_SYMBOL(PCIBIOS_MIN_IO);
>  EXPORT_SYMBOL(PCIBIOS_MIN_MEM);
>  #endif
>  
> +int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
> +                     enum pci_mmap_state mmap_state, int write_combine)
> +{
> +     unsigned long prot;
> +
> +     /*
> +      * Ignore write-combine; for now only return uncached mappings.
> +      */
> +     prot = pgprot_val(vma->vm_page_prot);
> +     prot = (prot & ~_CACHE_MASK) | _CACHE_UNCACHED;
> +     vma->vm_page_prot = __pgprot(prot);
> +
> +     return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
> +             vma->vm_end - vma->vm_start, vma->vm_page_prot);
> +}
> +
>  char * (*pcibios_plat_setup)(char *str) __devinitdata;
>  
>  char *__devinit pcibios_setup(char *str)
> 

Zhang, Le

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