linux-kernel - Re: [PATCH 2/8] firmware: qcom: scm: Convert SCM to platform driver

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Message-ID: <20160423044352.GA6968@hector.attlocal.net>
Date:	Fri, 22 Apr 2016 23:43:52 -0500
From:	Andy Gross <andy.gross@...aro.org>
To:	Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:	linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
	Stephen Boyd <sboyd@...eaurora.org>,
	linux-kernel@...r.kernel.org,
	Bjorn Andersson <bjorn.andersson@...ymobile.com>,
	jilai wang <jilaiw@...eaurora.org>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 2/8] firmware: qcom: scm: Convert SCM to platform driver

On Fri, Apr 22, 2016 at 04:11:11PM -0700, Bjorn Andersson wrote:
> On Fri 22 Apr 15:17 PDT 2016, Andy Gross wrote:
> 
> [..]
> > diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> [..]
> > +static struct qcom_scm *__scm;
> > +
> > +static int qcom_scm_clk_enable(void)
> > +{
> > +	int ret;
> > +
> > +	ret = clk_prepare_enable(__scm->core_clk);
> > +	if (ret)
> > +		goto bail;
> > +
> > +	if (__scm->iface_clk) {
> 
> No need for this check, the clk api accepts NULL.

Ah ok.  I wondered about that and then didn't check to see.

> > +		ret = clk_prepare_enable(__scm->iface_clk);
> > +		if (ret)
> > +			goto disable_core;
> > +	}
> > +
> > +	if (__scm->bus_clk) {
> 
> dito
> 
> > +		ret = clk_prepare_enable(__scm->bus_clk);
> > +		if (ret)
> > +			goto disable_iface;
> > +	}
> > +
> > +	return 0;
> > +
> > +disable_iface:
> > +	if (__scm->iface_clk)
> 
> dito
> 
> > +		clk_disable_unprepare(__scm->iface_clk);
> > +disable_core:
> > +	if (__scm->bus_clk)
> 
> and here
> 
> > +		clk_disable_unprepare(__scm->core_clk);
> > +bail:
> > +	return ret;
> > +}
> > +
> > +static void qcom_scm_clk_disable(void)
> > +{
> > +	clk_disable_unprepare(__scm->core_clk);
> > +	if (__scm->iface_clk)
> 
> and here
> 
> > +		clk_disable_unprepare(__scm->iface_clk);
> > +	if (__scm->bus_clk)
> 
> and here
> 
> > +		clk_disable_unprepare(__scm->bus_clk);
> > +}
> > +
> >  /**
> >   * qcom_scm_set_cold_boot_addr() - Set the cold boot address for cpus
> >   * @entry: Entry point function for the cpus
> > @@ -72,11 +121,17 @@ EXPORT_SYMBOL(qcom_scm_cpu_power_down);
> >   */
> >  bool qcom_scm_hdcp_available(void)
> >  {
> > -	int ret;
> > +	int ret = qcom_scm_clk_enable();
> > +
> > +	if (ret)
> > +		goto clk_err;
> 
> Just return here.

right.

> 
> >  
> >  	ret = __qcom_scm_is_call_available(QCOM_SCM_SVC_HDCP,
> > -		QCOM_SCM_CMD_HDCP);
> > +						QCOM_SCM_CMD_HDCP);
> > +
> > +	qcom_scm_clk_disable();
> >  
> > +clk_err:
> >  	return (ret > 0) ? true : false;
> 
> Unnecessary parenthesis.

will fix that.

> 
> >  }
> >  EXPORT_SYMBOL(qcom_scm_hdcp_available);
> > @@ -91,6 +146,89 @@ EXPORT_SYMBOL(qcom_scm_hdcp_available);
> >   */
> >  int qcom_scm_hdcp_req(struct qcom_scm_hdcp_req *req, u32 req_cnt, u32 *resp)
> >  {
> > -	return __qcom_scm_hdcp_req(req, req_cnt, resp);
> > +	int ret = qcom_scm_clk_enable();
> > +
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = __qcom_scm_hdcp_req(req, req_cnt, resp);
> > +	qcom_scm_clk_disable();
> > +	return ret;
> >  }
> >  EXPORT_SYMBOL(qcom_scm_hdcp_req);
> > +
> > +/**
> > + * qcom_scm_is_available() - Checks if SCM is available
> > + */
> > +bool qcom_scm_is_available(void)
> > +{
> > +	return !!__scm;
> > +}
> > +EXPORT_SYMBOL(qcom_scm_is_available);
> > +
> > +static int qcom_scm_probe(struct platform_device *pdev)
> > +{
> > +	struct qcom_scm *scm;
> > +	long rate;
> > +	int ret;
> > +
> > +	scm = devm_kzalloc(&pdev->dev, sizeof(*scm), GFP_KERNEL);
> > +	if (!scm)
> > +		return -ENOMEM;
> > +
> > +	scm->core_clk = devm_clk_get(&pdev->dev, "core");
> > +	if (IS_ERR(scm->core_clk)) {
> > +		if (PTR_ERR(scm->core_clk) != -EPROBE_DEFER)
> > +			dev_err(&pdev->dev, "failed to acquire core clk\n");
> > +		return PTR_ERR(scm->core_clk);
> > +	}
> > +
> > +	if (of_device_is_compatible(pdev->dev.of_node, "qcom,scm-apq8064")) {
> 
> Shouldn't this be reversed?

Right, I inverted this.  Will fix.

> 
> > +		scm->iface_clk = devm_clk_get(&pdev->dev, "iface");
> > +		if (IS_ERR(scm->iface_clk)) {
> > +			if (PTR_ERR(scm->iface_clk) != -EPROBE_DEFER)
> > +				dev_err(&pdev->dev, "failed to acquire iface clk\n");
> > +			return PTR_ERR(scm->iface_clk);
> > +		}
> > +
> > +		scm->bus_clk = devm_clk_get(&pdev->dev, "bus");
> > +		if (IS_ERR(scm->bus_clk)) {
> > +			if (PTR_ERR(scm->bus_clk) != -EPROBE_DEFER)
> > +				dev_err(&pdev->dev, "failed to acquire bus clk\n");
> > +			return PTR_ERR(scm->bus_clk);
> > +		}
> > +	}
> > +
> > +	/* vote for max clk rate for highest performance */
> > +	rate = clk_round_rate(scm->core_clk, INT_MAX);
> > +	ret = clk_set_rate(scm->core_clk, rate);
> > +	if (ret)
> > +		return ret;
> > +
> > +	__scm = scm;
> > +	__scm->dev = &pdev->dev;
> > +
> > +	return 0;
> > +}
> > +

Thanks for reviewing!