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SubjectRe: Q: PCI Driver ioremap
David Stroupe wrote:
>
> I am creating a PCI driver for a custom card and want to write 0xffff to
> a location offset from the base by 0x48 and
> have the following code:
>
> <snip>
> unsigned int io_addr;
> unsigned int io_size;
> void* base;
> pci_enable_device (pdev)
> io_addr = pci_resource_start(pdev, 0);
> io_size = pci_resource_len(pdev, 0);
> if ((pci_resource_flags(pdev, 0) & IORESOURCE_MEM)){
> if(check_mem_region(io_addr, io_size))
> DBG("Already In Use");//this is never reached
> request_mem_region(io_addr, io_size , "Card Driver");

In 2.4 and later, check request_mem_region return value, and never call
check_mem_region.

> base=ioremap(io_addr, io_size);
> if(base==0)
> DBG("memory mapped wrong\n");//this is never reached
> writew(0xffff, base + 0x48);
> <snip>
>
> The card is found, io_addr = 0xe9011000 and io_size = 0x200.
>
> The write is unsuccessful or at least the data never reaches the card.
> What am I doing incorrectly?

Looks correct to me... maybe you need to do
readw(base + 0x48)
to flush the transaction?

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