On Mon, Jan 10, 2011 at 21:43, Mike Frysinger wrote: > This converts the existing bfin_jtag_comm TTY driver to the HVC layer so > that the common HVC code can worry about all of the TTY/polling crap and > leave the Blackfin code to worry about the Blackfin bits. ive noticed a few downsides of converting to this ... hvc cant be built as a module. but not that big of a deal i guess. throughput seems to be a bit lower. the Blackfin JTAG hardware has basically a 4 byte fifo that is filled/consumed in a single shot. and the Blackfin can produce much faster than the host can consume. so atm, i have it send out 4 bytes, and the hvc layers take care of calling back into me at some point. if i add a busy loop to run a few hundred milliseconds (like HZ/4), it runs much nicer. but obviously doesnt give anyone else time to run. i cant schedule or anything as the write layers are called with a spin_lock_irqsave. any tips for how to speed this up a bit ? or is it a wash with hvc ? the code size also increased a bit ... old driver added up to ~1.7KiB while hvc stuff is like ~4KiB. but hvc does a nice job of keeping the Blackfin-specific piece small. so i guess it's a wash. -mike -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
