Q: PCI Driver ioremap

Q: PCI Driver ioremap

[David Stroupe]

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");
        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?

Thanks and best regards,
David

Re: Q: PCI Driver ioremap

[Jeff Garzik]

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?

-- 
Jeff Garzik      | "Why is it that attractive girls like you
Building 1024    |  always seem to have a boyfriend?"
MandrakeSoft     | "Because I'm a nympho that owns a brewery?"
                 |             - BBC TV show "Coupling"

Re: Q: PCI Driver ioremap

[Alan Cox]

> pci_enable_device (pdev)

Should check the return but that is fine I guess

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


Looks fine to me. Obviously you should a read to make sure the write
reaches the card from PCI posting but I'd expect that to timeout and
hit the card