Re: [dpdk-dev] [PATCH v4 6/9] raw/ioat: add device info function

[Bruce Richardson <bruce.richardson@intel.com>]

On Tue, Jul 02, 2019 at 03:33:25AM +0100, Hu, Jiayu wrote:
> 
> > -----Original Message-----
> > From: Richardson, Bruce
> > Sent: Monday, July 1, 2019 11:56 PM
> > To: dev@dpdk.org
> > Cc: thomas@monjalon.net; jerinj@marvell.com; Hu, Jiayu
> > <jiayu.hu@intel.com>; Richardson, Bruce <bruce.richardson@intel.com>;
> > Van Haaren, Harry <harry.van.haaren@intel.com>
> > Subject: [PATCH v4 6/9] raw/ioat: add device info function
> > 
> > Add in the "info_get" function to the driver, to allow us to query the
> > device. This allows us to have the unit test pick up the presence of
> > supported hardware or not.
> > 
> > Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> > Tested-by: Harry van Haaren <harry.van.haaren@intel.com>
> > ---
> > V4: Use TEST_SUCCESS in place of 0, when returning from test case.
> >     Minor documentation updates.
> > 
> > V2: Test case is placed in driver self-test routine
> > ---
> >  app/test/test_rawdev.c             | 11 ++++++++++
> >  doc/guides/rawdevs/ioat_rawdev.rst | 34
> > ++++++++++++++++++++++++++++++
> >  drivers/raw/ioat/ioat_rawdev.c     | 11 ++++++++++
> >  drivers/raw/ioat/rte_ioat_rawdev.h | 11 ++++++++++
> >  4 files changed, 67 insertions(+)
> > 
> > diff --git a/drivers/raw/ioat/ioat_rawdev.c b/drivers/raw/ioat/ioat_rawdev.c
> > index 86b5b2a77..2bfe2544d 100644
> > --- a/drivers/raw/ioat/ioat_rawdev.c
> > +++ b/drivers/raw/ioat/ioat_rawdev.c
> > @@ -34,10 +34,21 @@ static struct rte_pci_driver ioat_pmd_drv;
> >  #define IOAT_PMD_ERR(fmt, args...)    IOAT_PMD_LOG(ERR, fmt, ## args)
> >  #define IOAT_PMD_WARN(fmt, args...)   IOAT_PMD_LOG(WARNING, fmt, ##
> > args)
> > 
> > +static void
> > +ioat_dev_info_get(struct rte_rawdev *dev, rte_rawdev_obj_t dev_info)
> > +{
> > +	struct rte_ioat_rawdev_config *cfg = dev_info;
> > +	struct rte_ioat_rawdev *ioat = dev->dev_private;
> > +
> > +	if (cfg != NULL)
> > +		cfg->ring_size = ioat->ring_size;
> > +}
> 
> The CBDMA user may want to know the maximum copy length that the device
> supports and the NUMA location of the device. So can ioat_dev_info_get()
> return more device information?
> 
The NUMA node id is already part of the rawdev info structure returned to
the user.

As for maximum copy length, yes, that could be added.  However, since it's
actually a characteristic of the hardware, it could be just a define inside
the header file rather than needing to be returned per instance. Unlike
with ethdevs and cryptodevs, rawdevs always have a device-specific
dependency so using defines from the header should work fine, and not
everything needs to come via dev_info.

Regards,
/Bruce