Re: [PATCH V5 1/7] soc: qcom: geni: Support for ICC voting

[Akash Asthana <akashast@xxxxxxxxxxxxxx>]

Hi Matthias,

On 5/9/2020 12:33 AM, Matthias Kaehlcke wrote:
> On Fri, May 08, 2020 at 12:03:33PM +0530, Akash Asthana wrote:
> > Add necessary macros and structure variables to support ICC BW
> > voting from individual SE drivers.
> >
> > Signed-off-by: Akash Asthana <akashast@xxxxxxxxxxxxxx>
> > ---
> > Changes in V2:
> >   - As per Bjorn's comment dropped enums for ICC paths, given the three
> >     paths individual members
> >
> > Changes in V3:
> >   - Add geni_icc_get, geni_icc_vote_on and geni_icc_vote_off as helper API.
> >   - Add geni_icc_path structure in common header
> >
> > Changes in V4:
> >   - As per Bjorn's comment print error message in geni_icc_get if return
> >     value is not -EPROBE_DEFER.
> >   - As per Bjorn's comment remove NULL on path before calling icc_set_bw
> >     API.
> >   - As per Bjorn's comment drop __func__ print.
> >   - As per Matthias's comment, make ICC path a array instead of individual
> >     member entry in geni_se struct.
> >
> > Note: I have ignored below check patch suggestion because it was throwing
> >        compilation error as 'icc_ddr' is not compile time comstant.
> >
> > WARNING: char * array declaration might be better as static const
> >   - FILE: drivers/soc/qcom/qcom-geni-se.c:726:
> >   - const char *icc_names[] = {"qup-core", "qup-config", icc_ddr};
> >
> > Changes in V5:
> >   - As per Matthias's comment defined enums for ICC paths.
> >   - Integrate icc_enable/disable with power on/off call for driver.
> >   - As per Matthias's comment added icc_path_names array to print icc path name
> >     in failure case.
> >   - As per Georgi's suggestion assume peak_bw = avg_bw if not mentioned.
> >
> >   drivers/soc/qcom/qcom-geni-se.c | 92 +++++++++++++++++++++++++++++++++++++++++
> >   include/linux/qcom-geni-se.h    | 42 +++++++++++++++++++
> >   2 files changed, 134 insertions(+)
> >
> > diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
> > index 7d622ea..63403bf 100644
> > --- a/drivers/soc/qcom/qcom-geni-se.c
> > +++ b/drivers/soc/qcom/qcom-geni-se.c
> > @@ -92,6 +92,9 @@ struct geni_wrapper {
> >   	struct clk_bulk_data ahb_clks[NUM_AHB_CLKS];
> >   };
> >   
> > +static const char * const icc_path_names[] = {"qup-core", "qup-config",
> > +								"qup-memory"};
> > +
> >   #define QUP_HW_VER_REG			0x4
> >   
> >   /* Common SE registers */
> > @@ -720,6 +723,95 @@ void geni_se_rx_dma_unprep(struct geni_se *se, dma_addr_t iova, size_t len)
> >   }
> >   EXPORT_SYMBOL(geni_se_rx_dma_unprep);
> >   
> > +int geni_icc_get(struct geni_se *se, const char *icc_ddr)
> > +{
> > +	int i, icc_err;
> > +	const char *icc_names[] = {"qup-core", "qup-config", icc_ddr};
> > +
> > +	for (i = 0; i < ARRAY_SIZE(se->icc_paths); i++) {
> > +		if (!icc_names[i])
> > +			continue;
> > +
> > +		se->icc_paths[i].path = devm_of_icc_get(se->dev, icc_names[i]);
> > +		if (IS_ERR(se->icc_paths[i].path))
> > +			goto icc_get_failure;
> > +	}
> > +
> > +	return 0;
> > +
> > +icc_get_failure:
> > +	icc_err = PTR_ERR(se->icc_paths[i].path);
> > +	if (icc_err != -EPROBE_DEFER)
> > +		dev_err_ratelimited(se->dev, "Failed to get ICC path:%s, ret:%d\n",
> > +					icc_names[i], icc_err);
> > +	return icc_err;
> > +
> > +}
> > +EXPORT_SYMBOL(geni_icc_get);
> > +
> > +void geni_icc_bw_init(struct geni_icc_path *icc_paths, unsigned int avg_bw,
> > +			unsigned int peak_bw)
> I noticed that all callers of geni_icc_bw_init() pass 0 as
> 'peak_pw' (aka peak == avg). Unless there are plans to use other
> values for the peak bandwidth in the future it is pointless to
> track the bandwidth(s) in two variables. And if the bandwidth is
> tracked in a single variable this function is not needed.

As of now we are not aware of our peak requirement(avg requirement works 
good for us) so I am passing (peak = avg) as per Georgi's suggestion.

But I wanted to make this feature more generic and keeping the 
possibilty open that we might have to use other peak(!=0) value in future.

Regards,

Akash

> > +{
> > +	if (!peak_bw)
> > +		peak_bw = avg_bw;
> > +	icc_paths->avg_bw = avg_bw;
> > +	icc_paths->peak_bw = peak_bw;
> > +}
> > +EXPORT_SYMBOL(geni_icc_bw_init);

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