On Tue, Apr 19, 2011 at 11:12:50AM +0530, Nishant Sarmukadam wrote: > From: Pradeep Nemavat <pnemavat@xxxxxxxxxxx> > > Timestamp tx packets using a HW micro-second timer. > This timestamp will be compared to the current timestamp > in the hardware and if the difference is greater than 500ms, > the packet will be dropped. Why don't you do this entirely in the firmware? When a packet is put into the TX ring by the host, give it a timestamp of zero. When the firmware gets a TX interrupt, have it walk the TX ring from the last TX entry where a timestamp was written to (i.e. keep a separate index for this), and timestamp all TX ring entries that are marked as being FW OWNED but don't have a timestamp yet (and update your index). Then when the time comes to process the TX packet (i.e. it has reached the head of the TX queue), compare the timestamp with the current time. As an added bonus, this'll also work over USB/SPI/whatever other bus type where you cannot read some H/W microsecond timestamp register directly like you can on PCI(e) -- which sticks out like a sore thumb because it goes around the clean command / ring based host<->firmware interface. -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
