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Date:   Sat, 12 Oct 2019 07:00:44 -0400
From:   Brian Masney <masneyb@onstation.org>
To:     Bjorn Andersson <bjorn.andersson@linaro.org>
Cc:     georgi.djakov@linaro.org, robh+dt@kernel.org, agross@kernel.org,
        mark.rutland@arm.com, linux-arm-msm@vger.kernel.org,
        linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, jonathan@marek.ca
Subject: Re: [PATCH v2 2/2] interconnect: qcom: add msm8974 driver
Message-ID: <20191012110044.GA19009@onstation.org>
References: <20191005114605.5279-1-masneyb@onstation.org>
 <20191005114605.5279-3-masneyb@onstation.org>
 <20191011170506.GD571@minitux>
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On Fri, Oct 11, 2019 at 10:05:06AM -0700, Bjorn Andersson wrote:
> On Sat 05 Oct 04:46 PDT 2019, Brian Masney wrote:
> > diff --git a/drivers/interconnect/qcom/msm8974.c b/drivers/interconnect/qcom/msm8974.c
> [..]
> > +static void msm8974_icc_rpm_smd_send(struct device *dev, int rsc_type,
> > +				     char *name, int id, u64 val)
> > +{
> > +	int ret;
> > +
> > +	if (id == -1)
> > +		return;
> > +
> > +	/*
> > +	 * Setting the bandwidth requests for some nodes fails and this same
> > +	 * behavior occurs on the downstream MSM 3.4 kernel sources based on
> > +	 * errors like this in that kernel:
> > +	 *
> > +	 *   msm_rpm_get_error_from_ack(): RPM NACK Unsupported resource
> > +	 *   AXI: msm_bus_rpm_req(): RPM: Ack failed
> > +	 *   AXI: msm_bus_rpm_commit_arb(): RPM: Req fail: mas:32, bw:240000000
> > +	 *
> > +	 * Since there's no publicly available documentation for this hardware,
> > +	 * and the bandwidth for some nodes in the path can be set properly,
> > +	 * let's not return an error.
> > +	 */
> 
> So presumably all that matters for paths including these endpoints is
> the clk_set_rate() on the bus itself.

That's the case for the GPU at the very least.

> But I prefer that we merge it like you propose and then swing back to
> work out the details.

Thanks,

Brian


> 
> > +	ret = qcom_icc_rpm_smd_send(QCOM_SMD_RPM_ACTIVE_STATE, rsc_type, id,
> > +				    val);
> > +	if (ret)
> > +		dev_dbg(dev, "Cannot set bandwidth for node %s (%d): %d\n",
> > +			name, id, ret);
> > +}
> > +
> 
> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> 
> Regards,
> Bjorn