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List:       linux-i2c
Subject:    Re: [PATCH V4 3/9] soc: qcom: geni: Support for ICC voting
From:       Akash Asthana <akashast () codeaurora ! org>
Date:       2020-04-28 9:48:26
Message-ID: d0170d64-cde6-896c-5165-9d4cae37a574 () codeaurora ! org
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Hi Matthias,

On 4/16/2020 5:06 AM, Matthias Kaehlcke wrote:
> Hi Akash,
> 
> On Wed, Apr 15, 2020 at 03:53:12PM +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@codeaurora.org>
> > ---
> > 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};
> > 
> > 
> > drivers/soc/qcom/qcom-geni-se.c | 61 +++++++++++++++++++++++++++++++++++++++++
> > include/linux/qcom-geni-se.h    | 31 +++++++++++++++++++++
> > 2 files changed, 92 insertions(+)
> > 
> > diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
> > index 7d622ea..1527bc4 100644
> > --- a/drivers/soc/qcom/qcom-geni-se.c
> > +++ b/drivers/soc/qcom/qcom-geni-se.c
> > @@ -720,6 +720,67 @@ 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 path:%d, ret:%d\n",
> Better be explicit that it's an ICC path and log icc_names[i] instead of i.
> 
> > +					i, icc_err);
> > +	return icc_err;
> > +
> > +}
> > +EXPORT_SYMBOL(geni_icc_get);
> > +
> > +int geni_icc_vote_on(struct geni_se *se)
> > +{
> > +	int i, ret;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(se->icc_paths); i++) {
> > +		ret = icc_set_bw(se->icc_paths[i].path,
> > +			se->icc_paths[i].avg_bw, se->icc_paths[i].peak_bw);
> I'll leave it to others to decide whether it's ok to leave the
> implementation of the icc_enable/disable() APIs suggested on
> https://patchwork.kernel.org/patch/11467511/#23269555 for later.
> 
> > +		if (ret) {
> > +			dev_err_ratelimited(se->dev, "ICC BW voting failed on path:%d, ret:%d\n",
> > +					i, ret);
> Instead of logging the index, which isn't very expressive, you could have
> a static string array of the path names ({"core", "config", "ddr"} or
> similar) that is used when logging errors in _vote_on/off().
> 
> > +			return ret;
> > +		}
> > +	}
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL(geni_icc_vote_on);
> > +
> > +int geni_icc_vote_off(struct geni_se *se)
> > +{
> > +	int i, ret;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(se->icc_paths); i++) {
> > +		ret = icc_set_bw(se->icc_paths[i].path, 0, 0);
> > +		if (ret) {
> > +			dev_err_ratelimited(se->dev, "ICC BW remove failed on path:%d, ret:%d\n",
> > +					i, ret);
> > +			return ret;
> > +		}
> > +	}
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL(geni_icc_vote_off);
> > +
> > static int geni_se_probe(struct platform_device *pdev)
> > {
> > 	struct device *dev = &pdev->dev;
> > diff --git a/include/linux/qcom-geni-se.h b/include/linux/qcom-geni-se.h
> > index dd46494..b5b9316 100644
> > --- a/include/linux/qcom-geni-se.h
> > +++ b/include/linux/qcom-geni-se.h
> > @@ -6,6 +6,8 @@
> > #ifndef _LINUX_QCOM_GENI_SE
> > #define _LINUX_QCOM_GENI_SE
> > 
> > +#include <linux/interconnect.h>
> > +
> > /* Transfer mode supported by GENI Serial Engines */
> > enum geni_se_xfer_mode {
> > 	GENI_SE_INVALID,
> > @@ -25,6 +27,12 @@ enum geni_se_protocol_type {
> > struct geni_wrapper;
> > struct clk;
> > 
> > +struct geni_icc_path {
> > +	struct icc_path *path;
> > +	unsigned int avg_bw;
> > +	unsigned int peak_bw;
> > +};
> > +
> > /**
> > * struct geni_se - GENI Serial Engine
> > * @base:		Base Address of the Serial Engine's register block
> > @@ -33,6 +41,7 @@ struct clk;
> > * @clk:		Handle to the core serial engine clock
> > * @num_clk_levels:	Number of valid clock levels in clk_perf_tbl
> > * @clk_perf_tbl:	Table of clock frequency input to serial engine clock
> > + * @icc_paths:		Array of ICC paths for SE
> > */
> > struct geni_se {
> > 	void __iomem *base;
> > @@ -41,6 +50,7 @@ struct geni_se {
> > 	struct clk *clk;
> > 	unsigned int num_clk_levels;
> > 	unsigned long *clk_perf_tbl;
> > +	struct geni_icc_path icc_paths[3];
> You also need enums for the paths, otherwise you end up with code like
> this, which isn't really self-explanatory:
> 
> gi2c->se.icc_paths[0].avg_bw = GENI_DEFAULT_BW;
> gi2c->se.icc_paths[1].avg_bw = GENI_DEFAULT_BW;
> gi2c->se.icc_paths[2].avg_bw = Bps_to_icc(gi2c->clk_freq_out);
> 
> (from "[V4,5/9] i2c: i2c-qcom-geni: Add interconnect support")
> 
> I know Bjorn asked in v1 to remove the enums you had, however it was
> a slightly different context. If we are sticking to use an array of
> 'struct geni_icc_path' (which reduces redundant code) the enums are
> 'needed'.

Ok

Regards,

Akash

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,\na Linux \
Foundation Collaborative Project


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