linux-toradex.git/drivers/dma/ppc4xx, branch v3.4.45

dmaengine: ensure all DMA engine drivers initialize their cookies

2012-03-13T06:07:42+00:00

Ensure all DMA engine drivers initialize their cookies in the same way,
so that they all behave in a similar fashion.  This means their first
issued cookie will be 2 rather than 1, and will increment to INT_MAX
before returning 1 and starting over.

In connection with this, Dan Williams said:
> Russell King wrote:
> > Secondly, some DMA engine drivers initialize the dma_chan cookie to 0,
> > others to 1.  Is there a reason for this, or are these all buggy?
>
> I know that ioat and iop-adma expect 0 to mean "I have cleaned up this
> descriptor and it is idle", and would break if zero was an in-flight
> cookie value.  The reserved usage of zero is an driver internal
> concern, but I have no problem formalizing it as a reserved value.

Signed-off-by: Russell King 
Tested-by: Linus Walleij 
Reviewed-by: Linus Walleij 
Acked-by: Jassi Brar 
[imx-sdma.c & mxs-dma.c]
Tested-by: Shawn Guo 
Signed-off-by: Vinod Koul

dmaengine: fix cookie handling in iop-adma.c and ppc4xx/adma.c

2012-03-13T06:07:33+00:00

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 
Tested-by: Linus Walleij 
Reviewed-by: Linus Walleij 
Acked-by: Jassi Brar 
[imx-sdma.c & mxs-dma.c]
Tested-by: Shawn Guo 
Signed-off-by: Vinod Koul

dmaengine: consolidate tx_status functions

2012-03-13T06:07:14+00:00

Now that we have the completed cookie in the dma_chan structure, we
can consolidate the tx_status functions by providing a function to set
the txstate structure and returning the DMA status.  We also provide
a separate helper to set the residue for cookies which are still in
progress.

Signed-off-by: Russell King 
Tested-by: Linus Walleij 
Reviewed-by: Linus Walleij 
Acked-by: Jassi Brar 
[imx-sdma.c & mxs-dma.c]
Tested-by: Shawn Guo 
Signed-off-by: Vinod Koul

dmaengine: consolidate assignment of DMA cookies

2012-03-13T06:06:52+00:00

Everyone deals with assigning DMA cookies in the same way (it's part of
the API so they should be), so lets consolidate the common code into a
helper function to avoid this duplication.

Signed-off-by: Russell King 
Tested-by: Linus Walleij 
Reviewed-by: Linus Walleij 
Acked-by: Jassi Brar 
[imx-sdma.c & mxs-dma.c]
Tested-by: Shawn Guo 
Signed-off-by: Vinod Koul

dmaengine: add private header file

2012-03-13T06:06:44+00:00

Add a local private header file to contain definitions and declarations
which should only be used by DMA engine drivers.

We also fix linux/dmaengine.h to use LINUX_DMAENGINE_H to guard against
multiple inclusion.

Signed-off-by: Russell King 
Tested-by: Linus Walleij 
Reviewed-by: Linus Walleij 
Acked-by: Jassi Brar 
[imx-sdma.c & mxs-dma.c]
Tested-by: Shawn Guo 
Signed-off-by: Vinod Koul

dmaengine: move last completed cookie into generic dma_chan structure

2012-03-13T06:06:06+00:00

Every DMA engine implementation declares a last completed dma cookie
in their private dma channel structures.  This is pointless, and
forces driver specific code.  Move this out into the common dma_chan
structure.

Signed-off-by: Russell King 
Tested-by: Linus Walleij 
Reviewed-by: Linus Walleij 
Acked-by: Jassi Brar 
[imx-sdma.c & mxs-dma.c]
Tested-by: Shawn Guo 
Signed-off-by: Vinod Koul

Merge branch 'old_next' into next

2011-04-06T06:21:12+00:00

dma: use BUG_ON correctly in ppc4xx/adam.c, v4

2011-03-31T05:37:40+00:00

This patch makes BUG_ON() usage correct in drivers/dma/ppc4xx/adam.c

Cc: Vinod Koul 
Cc: Dan Williams 
Cc: Grant Likely 
Cc: Anatolij Gustschin 
Cc: Sean MacLennan 
Cc: Joe Perches 
Signed-off-by: Coly Li 
Signed-off-by: Vinod Koul

dt/powerpc: Eliminate users of of_platform_{,un}register_driver

2011-02-28T08:36:39+00:00

Get rid of old users of of_platform_driver in arch/powerpc.  Most
of_platform_driver users can be converted to use the platform_bus
directly.

Signed-off-by: Grant Likely

drivers/dma/ppc4xx: Use printf extension %pR for struct resource

2010-12-04T23:03:40+00:00

Using %pR standardizes the struct resource output.

Signed-off-by: Joe Perches 
Signed-off-by: Dan Williams