Subject: [PATCH] dmaengine: pl330: fix the race condition in pl330 driver.

From: [email-masked] (Vinod Koul)
Date: Mon, 30 Mar 2015 22:55:46 +0530

On Mon, Mar 30, 2015 at 10:17:17PM +0530, Jassi Brar wrote:
> On Fri, Mar 27, 2015 at 5:25 AM, Scott Branden <[email-masked]> wrote:
> > From: ismail <[email-masked]>
> >
> > Update the thread running index before issuing the
> > GO command to the DMAC.
> >
> > Tested-by: Mohamed Ismail Abdul Packir Mohamed <[email-masked]>
> > Reviewed-by: Ray Jui <[email-masked]>
> > Reviewed-by: Arun Parameswaran <[email-masked]>
> > Reviewed-by: Scott Branden <[email-masked]>
> > Signed-off-by: Scott Branden <[email-masked]>
> > Signed-off-by: Mohamed Ismail Abdul Packir Mohamed <[email-masked]>
> > ---
> >  drivers/dma/pl330.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
> > index 0e1f567..631642d 100644
> > --- a/drivers/dma/pl330.c
> > +++ b/drivers/dma/pl330.c
> > @@ -1072,11 +1072,11 @@ static bool _trigger(struct pl330_thread *thrd)
> >         /* Set to generate interrupts for SEV */
> >         writel(readl(regs + INTEN) | (1 << thrd->ev), regs + INTEN);
> >
> > +       thrd->req_running = idx;
> > +
> >         /* Only manager can execute GO */
> >         _execute_DBGINSN(thrd, insn, true);
> >
> > -       thrd->req_running = idx;
> > -
> It would help to know what the behavior looks like before and after
> the patch. If anything we should look at locking rather the
> reordering.
Yes that ia fair request, looking at changelog it is hard to understand the
issue seen?

-- 
~Vinod