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

[Akash Asthana <akashast@codeaurora.org>]

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@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};
>>
>> 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);

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