Addressing PCI memory

Takashi Oe toe at
Wed May 16 02:58:58 EST 2001

On Tue, 15 May 2001 18:34:50 +0200, Amelia De Vivo wrote:

> Hi all, I'm trying to write a driver for a 64 bit PCI device. Something
> like
> this works well under i386 Linux, but it doesn't work at all for Linux
> 2.2.15 by Yellow Dog:
>     struct pci_dev *dev = NULL;
>     dev = pci_find_device(vendor, device, dev);
>     pci_read_config_dword(dev, PCI_BASE_ADDRESS_0, &cards[0].addr0);
>     cards[0].vaddr = (void *) ioremap((cards[0].addr0 &
> PCI_BASE_ADDRESS_MEM_MASK), cards[0].size);
>     writeb('A',(cards[0].vaddr)+0x1000);
> I have a kernel panic on writeb. Has someone some suggestion?

Is PCI_COMMAND_MEMORY enabled on the device?  On Apple machines,
it's usually not enabled by default.  For 2.2.15, you'd need to
manually enable it.  [grep PCI_COMMAND_MEMORY for more info.]

Takashi Oe

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