On Wed, Jan 08, 2014 at 01:49:48PM +0800, Wenyou Yang wrote: > The patch is based on for-next branch of > git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git
Sorry, there was a patch from Richard which got applied but not pushed
out - I've pushed it now but it conflicts with this. Can you please
rebase? It should be a simple update from the looks of things.
> - tasklet_schedule(&as->tasklet);
> + atmel_spi_lock(as);
> + complete(&as->xfer_completion);
> + atmel_spi_unlock(as);
Why do you need to hold the lock to complete the transfer? That seems
very odd.
> + /*
> + * DMA map early, for performance (empties dcache ASAP) and
> + * better fault reporting.
> + */
> + if ((!msg->is_dma_mapped)
> + && (atmel_spi_use_dma(as, xfer) || as->use_pdc)) {
> + if (atmel_spi_dma_map_xfer(as, xfer) < 0)
> + return -ENOMEM;
> + }
Just a heads up at this point but this is most likely going to be moved
into the core soon.
> + if (xfer->delay_usecs)
> + udelay(xfer->delay_usecs);
If you convert to transfer_one() instead of transfer_one_message() then
this will be handled for you. What you're doing at the minute is still
an improvement so it should be OK but it'd be worth a look. There will
be further changes in this to factor out the DMA and message push code.
> + if (xfer->cs_change) {
> + cs_deactivate(as, msg->spi);
> + udelay(1);
> + cs_activate(as, msg->spi);
> + }
This is buggy, cs_change should flip the polarity of /CS rather than
bounce it on and off except if set on the last transfer in a message in
which case it should cause /CS to remain asserted after the message is
finished. Again, transfer_one() factors this out - you can at least
look at this to see what should be done.
> + if (as->stopping)
> + return -ESHUTDOWN;
You shouldn't need to worry about this, the core should handle this.
signature.asc
Description: Digital signature
