On Tue, Apr 27, 2010 at 04:48:40PM -0400, Charles Brown wrote: > All, > > I'm trying to write a device driver under ubuntu for a PCI card, and > exchange information with the card. > > The hardware engineer has configured the card to support BAR0 for > data to the card, and linux allocates memory at kernel boot and I am > able to write data from the driver to the card. > > For data coming from the card to the driver, the hardware engineer > expects the driver to allocate IO memory when the driver loads, and to > provide the physical address of that memory to the card - which the card > will use with its address translation register, to write data directly > into the provided I/O memory. I think you are confused here. "I/O Memory" is on the card. Your engineer is telling you he wants the card to transfer data to *host* memory. The card needs a "PCI Bus Address" (aka "physical address") to access that memory and Documentation/DMA-API.txt will explain that to you. > Using information from LDD3 I've been able to allocate IO memory, but > I can't find any PCI/kernel functions that allow me to tell the kernel > about this memory for the PCI card, and there's no way to tell the card > about this memory, except through writing the physical address back into > the IO memory associated to BAR0. > > How do I make this allocated memory available to the card? See how other drivers use interfaces described in Documentation/DMA-API.txt. e.g. drivers/net/bnx2 or drivers/scsi/mpt2sas It would be helpful if you could post the code some place. Assuming you can't and this driver will be released under GPL, just copy code from a similar driver. hth, grant -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
