Re: [PATCH 1/2] remoteproc: core: Add rproc OF look-up functions

From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Suman Anna <s-anna@ti.com>
Cc: Lee Jones <lee.jones@linaro.org>,
	Tony Lindgren <tony@atomide.com>,
	"ohad@wizery.com" <ohad@wizery.com>,
	"kernel@stlinux.com" <kernel@stlinux.com>,
	"linux-remoteproc@vger.kernel.org"
	<linux-remoteproc@vger.kernel.org>,
	"patrice.chotard@st.com" <patrice.chotard@st.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"ludovic.barre@st.com" <ludovic.barre@st.com>,
	"ssantosh@kernel.org" <ssantosh@kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	Dave Gerlach <d-gerlach@ti.com>
Subject: Re: [PATCH 1/2] remoteproc: core: Add rproc OF look-up functions
Date: Fri, 12 Aug 2016 11:07:51 -0700	[thread overview]
Message-ID: <20160812180751.GH26240@tuxbot> (raw)
In-Reply-To: <06f795ef-e71c-2cda-5306-5b75e0f15125@ti.com>

On Fri 12 Aug 09:37 PDT 2016, Suman Anna wrote:

> Hi Bjorn,
> 
> >> On 08/11/2016 02:31 AM, Lee Jones wrote:
> >>> On Wed, 10 Aug 2016, Suman Anna wrote:
> >>>
> >>>> On 08/10/2016 04:19 PM, Bjorn Andersson wrote:
> >>>>> On Wed 10 Aug 14:04 PDT 2016, Suman Anna wrote:
> >>>>>
> >>>>>> On 08/10/2016 03:40 PM, Bjorn Andersson wrote:
> >>>>>>> On Wed 10 Aug 12:37 PDT 2016, Suman Anna wrote:
> >>>>>>>
> >>>>>>>> Hi Lee, Bjorn,
> >>>>>>>>
> >>>>>>>> On 08/10/2016 12:40 PM, Bjorn Andersson wrote:
> >>>>>>>>> On Tue 19 Jul 08:49 PDT 2016, Lee Jones wrote:
> >>>>>>>>>
> >>>>>>>>>> - of_rproc_by_index(): look-up and obtain a reference to a rproc
> >>>>>>>>>>                        using the DT phandle "rprocs" and a index.
> >>>>>>>>>>
> >>>>>>>>>> - of_rproc_by_name():  lookup and obtain a reference to a rproc
> >>>>>>>>>>                        using the DT phandle "rprocs" and "rproc-names".
> >>>>>>>>>>
> >>>>>>>>>> Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
> >>>>>>>>>> Signed-off-by: Lee Jones <lee.jones@linaro.org>
> >>>>>>>>>> ---
> >>>>>>>>>
> >>>>>>>>> I'm happy with this, so I whipped up a binding document describing our
> >>>>>>>>> two new properties. Waiting for an opinion on that before I merge this.
> 
> One last comment on this is the return code convention change on these
> rproc_get APIs. I am fine in general with returning ERR_PTRs, but most
> of the remoteproc code is using NULL checking for rproc. If you remember
> the discussion back during the hwspinlock DT conversion [1], Ohad
> preferred to return NULL, and that's why even the rproc_get_by_phandle
> was returning NULL. We ought to make this consistent across the board if
> we want to make this switch.
> 

I think it makes sense to return the actual error from these functions,
if nothing else to keep it consistent with other frameworks.

The other case I see returning NULL is rproc_alloc(), which is think is
analog to kmalloc(), so I think that's fine to keep.

Luckily wkup_m3 is the only consumer of this API in the kernel today, so
we shouldn't have any issues wrt changing the return value here.

> regards
> Suman
> 
> [1] http://marc.info/?t=138965891200008

Regards,
Bjorn