Re: [PATCH V4 3/9] soc: qcom: geni: Support for ICC voting

[Akash Asthana <akashast@codeaurora.org>]

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

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