Re: [PATCH v2 0/9] DMA engine cookie handling cleanups

[Vinod Koul <vinod.koul@intel.com>]

On Tue, 2012-03-13 at 12:31 +0000, Russell King - ARM Linux wrote:
> On Tue, Mar 13, 2012 at 02:10:36PM +0530, Vinod Koul wrote:
> > Please see if the below patch is the right fix for build failures in
> > addition to one suggested by Jassi.
> 
> I'm not sure that Jassi's solution is correct - and I'm wondering whether
> any of the DMA engine drivers do the right thing when transfers are
> terminated.  Is it right for the DMA status function to return IN_PROGRESS
> for a previously submitted cookie which has been terminated?
> 
> I can see two answers to that, both equally valid:
> 
> 1. It allows you to find out exactly where the DMA engine got to before
>    the transfer was terminated, and therefore recover from the termination
>    if you wish to.
> 
> 2. Returning in-progress when a cookie will never be completed is
>    misleading, and could be misinterpreted by users of the tx_status
>    function, especially if they are waiting for a particular transaction
>    to complete.
> 
> Maybe we need to introduce a DMA_TERMINATED status?
I would agree with you that DMA_TERMINATED seems to be correct option.
IN_PROGRESS would certainly confuse... 
I will drop Jassi's fix from this branch. Care to send the patch?
> 
> > -------------------x-------------------------x----------------------
> > 
> > >From 949ff5b8d46b5e3435d21b2651ce3a2599208d44 Mon Sep 17 00:00:00 2001
> > From: Vinod Koul <vinod.koul@linux.intel.com>
> > Date: Tue, 13 Mar 2012 11:58:12 +0530
> > Subject: [PATCH] dmaengine: fix for cookie changes and merge
> > 
> > Fixed trivial issues in drivers:
> > 	drivers/dma/imx-sdma.c
> > 	drivers/dma/intel_mid_dma.c
> > 	drivers/dma/ioat/dma_v3.c
> > 	drivers/dma/iop-adma.c
> > 	drivers/dma/sirf-dma.c
> > 	drivers/dma/timb_dma.c
> > 
> > Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
> > ---
> >  drivers/dma/imx-sdma.c      |    1 +
> >  drivers/dma/intel_mid_dma.c |    1 +
> >  drivers/dma/ioat/dma_v3.c   |    1 +
> >  drivers/dma/iop-adma.c      |    1 +
> >  drivers/dma/sirf-dma.c      |    2 ++
> >  drivers/dma/timb_dma.c      |    6 +-----
> >  6 files changed, 7 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
> > index ccfc7c4..81f9d57 100644
> > --- a/drivers/dma/imx-sdma.c
> > +++ b/drivers/dma/imx-sdma.c
> > @@ -1127,6 +1127,7 @@ static void sdma_issue_pending(struct dma_chan *chan)
> >  	struct sdma_engine *sdma = sdmac->sdma;
> >  
> >  	if (sdmac->status == DMA_IN_PROGRESS)
> > +		sdma_enable_channel(sdma, sdmac->channel);
> >  }
> >  
> >  #define SDMA_SCRIPT_ADDRS_ARRAY_SIZE_V1	34
> 
> This looks like a merge conflict resolution.  I don't see this being
> caused by my patches as I haven't touched this function.
> 
> > diff --git a/drivers/dma/intel_mid_dma.c b/drivers/dma/intel_mid_dma.c
> > index d599d96..2449812 100644
> > --- a/drivers/dma/intel_mid_dma.c
> > +++ b/drivers/dma/intel_mid_dma.c
> > @@ -477,6 +477,7 @@ static enum dma_status intel_mid_dma_tx_status(struct dma_chan *chan,
> >  						dma_cookie_t cookie,
> >  						struct dma_tx_state *txstate)
> >  {
> > +	struct intel_mid_dma_chan *midc = to_intel_mid_dma_chan(chan);
> >  	enum dma_status ret;
> >  
> >  	ret = dma_cookie_status(chan, cookie, txstate);
> 
> Ditto (my patches don't introduce new this new midc, nor do they remove
> that line.)
> 
> > diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
> > index 145eda2..2c4476c 100644
> > --- a/drivers/dma/ioat/dma_v3.c
> > +++ b/drivers/dma/ioat/dma_v3.c
> > @@ -61,6 +61,7 @@
> >  #include <linux/dmaengine.h>
> >  #include <linux/dma-mapping.h>
> >  #include <linux/prefetch.h>
> > +#include "../dmaengine.h"
> >  #include "registers.h"
> >  #include "hw.h"
> >  #include "dma.h"
> > diff --git a/drivers/dma/iop-adma.c b/drivers/dma/iop-adma.c
> > index 1f3a703..4499f88 100644
> > --- a/drivers/dma/iop-adma.c
> > +++ b/drivers/dma/iop-adma.c
> > @@ -894,6 +894,7 @@ static enum dma_status iop_adma_status(struct dma_chan *chan,
> >  					struct dma_tx_state *txstate)
> >  {
> >  	struct iop_adma_chan *iop_chan = to_iop_adma_chan(chan);
> > +	int ret;
> 
> This was "enum dma_status ret;" before I accidentally removed it.  It
> probably should be again, rather than an int.
> 
> >  
> >  	ret = dma_cookie_status(chan, cookie, txstate);
> >  	if (ret == DMA_SUCCESS)
> > diff --git a/drivers/dma/sirf-dma.c b/drivers/dma/sirf-dma.c
> > index a2cde85..45ba352 100644
> > --- a/drivers/dma/sirf-dma.c
> > +++ b/drivers/dma/sirf-dma.c
> > @@ -18,6 +18,8 @@
> >  #include <linux/of_platform.h>
> >  #include <linux/sirfsoc_dma.h>
> >  
> > +#include "dmaengine.h"
> > +
> >  #define SIRFSOC_DMA_DESCRIPTORS                 16
> >  #define SIRFSOC_DMA_CHANNELS                    16
> >  
> 
> Hmm, guess that's what happens when old patches are brought forward and
> things from the original series are forgotten...
> 
> > diff --git a/drivers/dma/timb_dma.c b/drivers/dma/timb_dma.c
> > index 7805996..d408c22 100644
> > --- a/drivers/dma/timb_dma.c
> > +++ b/drivers/dma/timb_dma.c
> > @@ -510,17 +510,13 @@ static void td_free_chan_resources(struct dma_chan *chan)
> >  static enum dma_status td_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
> >  				    struct dma_tx_state *txstate)
> >  {
> > -	struct timb_dma_chan *td_chan =
> > -		container_of(chan, struct timb_dma_chan, chan);
> >  	enum dma_status ret;
> >  
> >  	dev_dbg(chan2dev(chan), "%s: Entry\n", __func__);
> >  
> >  	ret = dma_cookie_status(chan, cookie, txstate);
> >  
> > -	dev_dbg(chan2dev(chan),
> > -		"%s: exit, ret: %d, last_complete: %d, last_used: %d\n",
> > -		__func__, ret, last_complete, last_used);
> > +	dev_dbg(chan2dev(chan), "%s: exit, ret: %d\n", 	__func__, ret);
> >  
> >  	return ret;
> >  }
> > -- 
> > 1.7.0.4
> > 
> > 
> > 
> > 
> > -- 
> > ~Vinod
> > 
> 
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-- 
~Vinod