RE: [PATCH v4 10/17] remoteproc: add helper function to check carveout device address

[Loic PALLARDY]

Hi Suman,

> -----Original Message-----
> From: Suman Anna <s-anna@xxxxxx>
> Sent: mercredi 24 octobre 2018 00:14
> To: Loic PALLARDY <loic.pallardy@xxxxxx>; bjorn.andersson@xxxxxxxxxx;
> ohad@xxxxxxxxxx
> Cc: linux-remoteproc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> Arnaud POULIQUEN <arnaud.pouliquen@xxxxxx>;
> benjamin.gaignard@xxxxxxxxxx
> Subject: Re: [PATCH v4 10/17] remoteproc: add helper function to check
> carveout device address
> 
> Hi Loic,
> 
> On 7/27/18 8:14 AM, Loic Pallardy wrote:
> > This patch introduces a function to verify that a specified carveout
> > is fitting request device address and associated length
> >
> > Signed-off-by: Loic Pallardy <loic.pallardy@xxxxxx>
> > ---
> >  drivers/remoteproc/remoteproc_core.c | 47
> ++++++++++++++++++++++++++++++++++++
> >  1 file changed, 47 insertions(+)
> >
> > diff --git a/drivers/remoteproc/remoteproc_core.c
> b/drivers/remoteproc/remoteproc_core.c
> > index 1e0fe3e..5dd5edf 100644
> > --- a/drivers/remoteproc/remoteproc_core.c
> > +++ b/drivers/remoteproc/remoteproc_core.c
> > @@ -259,6 +259,53 @@ struct rproc_mem_entry *
> >  	return mem;
> >  }
> >
> > +/**
> > + * rproc_check_carveout_da() - Check specified carveout da configuration
> > + * @rproc: handle of a remote processor
> > + * @mem: pointer on carveout to check
> > + * @da: area device address
> > + * @len: associated area size
> > + *
> > + * This function is a helper function to verify requested device area
> (couple
> > + * da, len) is part of specified carevout.
> 
> %s/carevout/carveout/
OK
> 
> > + *
> > + * Return: 0 if carveout matchs request else -ENOMEM
> 
> %s/matchs/matches/
OK
> 
> > + */
> > +int rproc_check_carveout_da(struct rproc *rproc, struct
> rproc_mem_entry *mem,
> 
> static int since this seems to be only a local function.
OK
> 
> > +			    u32 da, u32 len)
> > +{
> > +	struct device *dev = &rproc->dev;
> > +	int delta = 0;
> > +
> > +	/* Check requested resource length */
> > +	if (len > mem->len) {
> > +		dev_err(dev, "Registered carveout doesn't fit len
> request\n");
> > +		return -ENOMEM;
> 
> ENOMEM not typically used for these kind of errors, you were probably
> inclined to used this since it is dealing with memory.

-EINVAL will be better
> 
> > +	}
> > +
> 
> Both the below codepaths are exercised only when da is not
> FW_RSC_ADDR_ANY, and you are returning 0 otherwise (which is the case of
> matches as per your description above). Is that what you really want -
> should it be an error

Yes when da is equal to FW_RSC_ADDR_ANY we should check the length too

> 
> > +	if (da != FW_RSC_ADDR_ANY && mem->da == FW_RSC_ADDR_ANY)
> {
> > +		/* Update existing carveout da */
> > +		mem->da = da;
> 
> Where would you need to update this?
In that case, we have 2 carveouts with the same name.
One has some fixed requests. The other one has none.
The goal here is to align both on the one which has the strongest requirements.
I think length is missing.

Regards,
Loic

> 
> regards
> Suman
> 
> > +	} else if (da != FW_RSC_ADDR_ANY && mem->da !=
> FW_RSC_ADDR_ANY) {
> > +		delta = da - mem->da;
> > +
> > +		/* Check requested resource belongs to registered carveout
> */
> > +		if (delta < 0) {
> > +			dev_err(dev,
> > +				"Registered carveout doesn't fit da
> request\n");
> > +			return -ENOMEM;
> > +		}
> > +
> > +		if (delta + len > mem->len) {
> > +			dev_err(dev,
> > +				"Registered carveout doesn't fit len
> request\n");
> > +			return -ENOMEM;
> > +		}
> > +	}
> > +
> > +	return 0;
> 
> 
> > +}
> > +
> >  int rproc_alloc_vring(struct rproc_vdev *rvdev, int i)
> >  {
> >  	struct rproc *rproc = rvdev->rproc;
> >