linux-kernel - Re: [PATCH 4/5] soc: qcom: wcnss_ctrl: Make wcnss

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Date:	Thu, 31 Mar 2016 12:39:24 -0700
From:	Bjorn Andersson <bjorn.andersson@...aro.org>
To:	Andy Gross <andy.gross@...aro.org>
Cc:	Rob Herring <robh+dt@...nel.org>, linux-arm-msm@...r.kernel.org,
	linux-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/5] soc: qcom: wcnss_ctrl: Make wcnss_ctrl parent the
 other components

On Thu 31 Mar 11:47 PDT 2016, Andy Gross wrote:

> On Mon, Mar 28, 2016 at 09:35:25PM -0700, Bjorn Andersson wrote:
> > We need the signal from wcnss_ctrl indicating that the firmware is up
> > and running before we can communicate with the other components of the
> > chip. So make these other components children of the wcnss_ctrl device,
> > so they can be probed in order.
> > 
> > The process seems to take between 1/2-5 seconds, so this is done in a
> > worker, instead of holding up the probe.
> > 
> > Also adding the wait for a cbc completion if the firmware indicates this is
> > needed - like on 8016.
> 
> Can you define what a CBC is?
> 

Unfortunately I have no clue and have not yet seen this abbreviation in
any documentation...

> 
> <snip>
> 
> >  /**
> >   * wcnss_download_nv() - send nv binary to WCNSS
> > - * @work:	work struct to acquire wcnss context
> > + * @wcnss:	wcnss_ctrl state handle
> > + *
> > + * Returns 1 on success or 2 to indicate upcoming cbc completion. Negative
> 
> maybe a nit, but define the return values
> 

I'll remap them a step down, so the function returns 0 on success and 1
on "need to wait for cbc complete". That way we don't have an undefined
hole in the return set as well.

> > + * errno on failure.
> >   */
> > -static void wcnss_download_nv(struct work_struct *work)
> > +static int wcnss_download_nv(struct wcnss_ctrl *wcnss)
> >  {
> > -	struct wcnss_ctrl *wcnss = container_of(work, struct wcnss_ctrl, download_nv_work);
> >  	struct wcnss_download_nv_req *req;
> >  	const struct firmware *fw;
> >  	const void *data;
> > @@ -178,7 +207,7 @@ static void wcnss_download_nv(struct work_struct *work)
> >  
> >  	req = kzalloc(sizeof(*req) + NV_FRAGMENT_SIZE, GFP_KERNEL);
> >  	if (!req)
> > -		return;
> > +		return -ENOMEM;
> >  
> >  	ret = request_firmware(&fw, NVBIN_FILE, wcnss->dev);
> >  	if (ret) {
> 
> <snip>
> 
> > +static void wcnss_async_probe(struct work_struct *work)
> > +{
> > +	struct wcnss_ctrl *wcnss = container_of(work, struct wcnss_ctrl, probe_work);
> > +	int ret;
> > +
> > +	ret = wcnss_request_version(wcnss);
> > +	if (ret < 0)
> > +		return;
> > +
> > +	ret = wcnss_download_nv(wcnss);
> > +	if (ret < 0)
> > +		return;
> > +
> > +	/* Wait for pending CBC completion if download nv returns 2 */
> > +	if (ret == 2) {
> 
> Perhaps have a #define for the value is warranted
> 

With the above remap I can rename ret here to need_cbc and the code will
be understandable.

> > +		ret = wait_for_completion_timeout(&wcnss->cbc, WCNSS_REQUEST_TIMEOUT);
> > +		if (!ret)
> > +			dev_err(wcnss->dev, "expected cbc completion\n");
> > +	}
> > +
> > +	of_platform_populate(wcnss->dev->of_node, NULL, NULL, wcnss->dev);
> >  }
> 
> <snip>

Thanks for the feedback!

Regards,
Bjorn