Re: [PATCH V2 07/15] coresight: tmc: allocating memory when needed

[Suzuki K Poulose]

On 19/04/16 13:55, Suzuki K Poulose wrote:
> On 12/04/16 18:54, Mathieu Poirier wrote:
> > In it's current form the TMC probe() function allocates
> > trace buffer memory at boot time, event if coresight isn't
> > used.  This is highly inefficient since trace buffers can
> > occupy a lot of memory that could be used otherwised.
> >
> > This patch allocates trace buffers on the fly, when the
> > coresight subsystem is solicited.  Allocated buffers are
> > released when traces are read using the device descriptors
> > under /dev.

> >       /* Wait for TMCSReady bit to be set */
> > @@ -110,19 +108,68 @@ static void tmc_etf_disable_hw(struct tmc_drvdata *drvdata)
> >
> >   static int tmc_enable_etf_sink(struct coresight_device *csdev, u32 mode)
> >   {
> > +    bool allocated = false;
>
> nit: does "used" or buf_used sound more suitable than allocated ?
>
> > +    char *buf = NULL;
> >       unsigned long flags;
> >       struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> >
> > +     /* This shouldn't be happening */
> > +    WARN_ON(mode != CS_MODE_SYSFS);

And we should proceed no further. Return immediately.