lkml.org 
[lkml]   [2008]   [Jan]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Custom PCIe Device Driver
Sanka Piyaratna wrote:
> Hi Everyone,
>
> I am currently developing a custom PCIe device and the Linux kernel
> driver for this. I am able to use the device as a character device with
> PIO and now I am working on getting the DMA to work. I have implemented
> 2 BARs (BAR0 - mem and BAR5 - mem) in the PCIe device. I have
> implemented the DMA in my custom device firmware to transfer a block of
> memory via the PCIe bus and now trying to get this to work with the
> device driver.
>
> As I understand it, I can get hold of the PCI bus to become the bus
> master and then initiate the DMA transfer from my device. However, I
> don't understand how I can specify within my kernel driver how to
> specify which BAR to use.
>
> Does this mean when I initiate a transfer from the hardware, the memory
> get transferred into the location allocated by by pci_map_single()
> function regardless of which BAR the memory comes from? or do I need to
> specify the BAR using a mask?
>
> Would some one be able to point me to an example code please?
>
> Thanks and Regards,
>
> Sanka

Your question doesn't seem to make much sense. DMA transfers have
nothing to do with BARs at all, they don't come "from" or "to" one.

--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/



\
 
 \ /
  Last update: 2008-01-27 02:47    [W:0.053 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site