Messages in this thread | | | Date | Fri, 11 Oct 2013 06:33:43 -0700 | From | Greg KH <> | Subject | Re: [PATCH 1/2] dma: Add interface to calculate data transferred |
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On Fri, Oct 11, 2013 at 05:42:17PM -0400, Youquan Song wrote: > Currently, the DMA channel calculates its data transferred only at network > device driver. When other devices like UART or SPI etc, transfers data by DMA > mode, but it always shows 0 at /sys/class/dma/dma0chan*/bytes_transferred.
Is that really a problem? I have never heard anyone complaining about it. Where are the reports of this?
> This patch add a new function which will calculate how many the data has been > transferred after doing it by DMA mode. It can be used by other modules and > also simplify current duplicated code. > > Signed-off-by: Youquan Song <youquan.song@intel.com> > --- > drivers/dma/dmaengine.c | 35 +++++++++++++++++++---------------- > include/linux/dmaengine.h | 3 +++ > 2 files changed, 22 insertions(+), 16 deletions(-) > > diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c > index 9162ac8..4356a7e 100644 > --- a/drivers/dma/dmaengine.c > +++ b/drivers/dma/dmaengine.c > @@ -901,6 +901,23 @@ void dma_async_device_unregister(struct dma_device *device) > } > EXPORT_SYMBOL(dma_async_device_unregister); > > +dma_cookie_t > +dma_tx_submit_cal(struct dma_async_tx_descriptor *tx, > + struct dma_chan *chan, size_t len) > +{ > + > + dma_cookie_t cookie; > + cookie = tx->tx_submit(tx); > + > + preempt_disable(); > + __this_cpu_add(chan->local->bytes_transferred, len); > + __this_cpu_inc(chan->local->memcpy_count); > + preempt_enable(); > + > + return cookie; > + > +}
You create a function, yet no driver can use it as it's not exported, so I guess you don't want anyone to use it :)
Anyway, I don't think this is a good idea, see my response to the serial driver patch for why not.
sorry,
greg k-h
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