diff options
| author | Russell King - ARM Linux <linux@arm.linux.org.uk> | 2012-03-06 22:36:07 +0000 |
|---|---|---|
| committer | Vinod Koul <vinod.koul@linux.intel.com> | 2012-03-13 11:37:33 +0530 |
| commit | 2a926e46022ad7a03e0ac167d8c2b0d88c12c5a8 (patch) | |
| tree | 7e31a02d6e6d90571d6dd88ebf31db2e5ca8d5c0 /drivers/dma/iop-adma.c | |
| parent | d3ee98cdcd6198ea1cf75c603178acc8a805b69b (diff) | |
dmaengine: fix cookie handling in iop-adma.c and ppc4xx/adma.c
Dan Williams said:
> > Russell King wrote:
> > Firstly, we have DMA_MIN_COOKIE which has value 1 - so any cookies below
> > that aren't valid. That seems sane.
> >
> > We seem to have different behaviours:
> >
> > - cookie = c->cookie;
> > - cookie++;
> > - if (cookie < 0)
> > - cookie = 1;
> > - c->cookie = cookie;
> > - tx->cookie = cookie;
> >
> > c->cookie here is initialized to zero, so the first cookie given out will
> > be 1. This is how most DMA engine drivers implement this.
> >
> > Then we have this:
> >
> > cookie = chan->common.cookie;
> > cookie++;
> > if (cookie <= 1)
> > cookie = 2;
> >
> > /* initialize the completed cookie to be less than
> > * the most recently used cookie
> > */
> > chan->common.completed_cookie = cookie - 1;
> > chan->common.cookie = sw_desc->async_tx.cookie = cookie;
> >
> > Again, chan->common.cookie starts off at 0. The first cookie given out
> > will be 2, and 1 will never be used. There are three drivers which
> > implement it this way.
> >
> > Why is there this difference, and can these three be corrected to behave
> > the same way as the first (and therefore the assignment of cookies
> > consolidated?)
>
> Yes, they should be consolidated, and I believe they have drifted only
> because there were no good common helpers and murphy's law took over.
So lets fix this up to use the common dma_cookie_assign() helper.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Jassi Brar <jassisinghbrar@gmail.com>
[imx-sdma.c & mxs-dma.c]
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
Diffstat (limited to 'drivers/dma/iop-adma.c')
| -rw-r--r-- | drivers/dma/iop-adma.c | 12 |
1 files changed, 2 insertions, 10 deletions
diff --git a/drivers/dma/iop-adma.c b/drivers/dma/iop-adma.c index b1e3be089c52..4370b1015f73 100644 --- a/drivers/dma/iop-adma.c +++ b/drivers/dma/iop-adma.c @@ -1622,16 +1622,12 @@ static void iop_chan_start_null_memcpy(struct iop_adma_chan *iop_chan) iop_desc_set_dest_addr(grp_start, iop_chan, 0); iop_desc_set_memcpy_src_addr(grp_start, 0); - cookie = iop_chan->common.cookie; - cookie++; - if (cookie <= 1) - cookie = 2; + cookie = dma_cookie_assign(&sw_desc->async_tx); /* initialize the completed cookie to be less than * the most recently used cookie */ iop_chan->common.completed_cookie = cookie - 1; - iop_chan->common.cookie = sw_desc->async_tx.cookie = cookie; /* channel should not be busy */ BUG_ON(iop_chan_is_busy(iop_chan)); @@ -1679,16 +1675,12 @@ static void iop_chan_start_null_xor(struct iop_adma_chan *iop_chan) iop_desc_set_xor_src_addr(grp_start, 0, 0); iop_desc_set_xor_src_addr(grp_start, 1, 0); - cookie = iop_chan->common.cookie; - cookie++; - if (cookie <= 1) - cookie = 2; + cookie = dma_cookie_assign(&sw_desc->async_tx); /* initialize the completed cookie to be less than * the most recently used cookie */ iop_chan->common.completed_cookie = cookie - 1; - iop_chan->common.cookie = sw_desc->async_tx.cookie = cookie; /* channel should not be busy */ BUG_ON(iop_chan_is_busy(iop_chan)); |