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From: "Wu, Jingjing" <jingjing.wu@intel.com>
To: "Li, Xiaoyun" <xiaoyun.li@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
	"Maslekar, Omkar" <omkar.maslekar@intel.com>
Subject: Re: [dpdk-dev] [PATCH v3] raw/ntb: add Icelake support for Intel NTB
Date: Mon, 7 Sep 2020 16:15:46 +0000	[thread overview]
Message-ID: <BN6PR11MB405299668C8854F91F7F3D38E3280@BN6PR11MB4052.namprd11.prod.outlook.com> (raw)
In-Reply-To: <DM5PR11MB175375E5B7CC5F2790AA6A7099280@DM5PR11MB1753.namprd11.prod.outlook.com>

> > > -	rte_write64(limit, limit_addr);
> > > +	if (is_gen3_ntb(hw)) {
> > > +		/* Setup the external point so that remote can access. */
> > > +		xlat_off = XEON_EMBAR1_OFFSET + 8 * mw_idx;
> > > +		xlat_addr = hw->hw_addr + xlat_off;
> > > +		limit_off = XEON_EMBAR1XLMT_OFFSET +
> > > +			    mw_idx * XEON_BAR_INTERVAL_OFFSET;
> > > +		limit_addr = hw->hw_addr + limit_off;
> > > +		base = rte_read64(xlat_addr);
> > > +		base &= ~0xf;
> > > +		limit = base + size;
> > > +		rte_write64(limit, limit_addr);
> > > +	} else if (is_gen4_ntb(hw)) {
> > Can we use a variable in struct to indicate it's gen4 or gen3 after init instead of
> > check it every time?
> 
> What's the difference? It comes from the value in hw->pci_dev->id.device_id.
> Checking it in this way is trying to make it easier to extend it for gen2 ntb in the future.
> It's not either gen3 or gen4.
> I don't think it makes sense to have a bool value to indicate it's gen3 or gen4.

Understand, as the inline function is very simple, it looks OK.
> 
> >
> > > +		/* Set translate base address index register */
> > > +		xlat_off = XEON_GEN4_IM1XBASEIDX_OFFSET +
> > > +			   mw_idx * XEON_GEN4_XBASEIDX_INTERVAL;
> > > +		xlat_addr = hw->hw_addr + xlat_off;
> > > +		rte_write16(rte_log2_u64(size), xlat_addr);
> > > +	} else {
> > > +		rte_write64(base, limit_addr);
> > > +		rte_write64(0, xlat_addr);
> > > +		return -ENOTSUP;
> > > +	}
> > Is the else branch necessary? As if neither gen3 or gen4, the init would fail.
> > Would be better to print an ERR instead of just return NO support.
> 
> I don't think so.
> Yes. It will fail in init. Returning err is to stop other following actions like in
> intel_ntb_vector_bind() since it should be stopped.
> And I'd like to keep them in one coding style. As to the print, I think that can be upper
> layer's job to check the value and print err.
> Choosing ENOTSUP is because that in init, if it's not supported hw, it will return -
> ENOTSUP err.
> 
I cannot say what you did is incorrect. But try to think it like this way:  according current API design, ntb raw device is allocated when driver probe, if init fails, raw device would be free. How the ops be called? 

> > >
> > >  	return 0;
> > >  }
> >


  reply	other threads:[~2020-09-07 16:15 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-31  4:59 [dpdk-dev] [PATCH] " Xiaoyun Li
2020-09-07  1:46 ` [dpdk-dev] [PATCH v2] " Xiaoyun Li
2020-09-07  2:21 ` [dpdk-dev] [PATCH v3] " Xiaoyun Li
2020-09-07  8:34   ` Wu, Jingjing
2020-09-07  9:18     ` Li, Xiaoyun
2020-09-07 16:15       ` Wu, Jingjing [this message]
2020-09-08  1:53         ` Li, Xiaoyun
2020-09-08  3:27 ` [dpdk-dev] [PATCH v4] raw/ntb: add Ice Lake " Xiaoyun Li
2020-09-08  4:43   ` Wu, Jingjing
2020-10-05 23:25     ` Thomas Monjalon

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