Re: [PATCH v5 4/5] cpufreq: qcom: Update the bandwidth levels on frequency change

[Viresh Kumar]

On 28-05-20, 01:51, Sibi Sankar wrote:
> Add support to parse optional OPP table attached to the cpu node when
> the OPP bandwidth values are populated. This allows for scaling of
> DDR/L3 bandwidth levels with frequency change.
> 
> Signed-off-by: Sibi Sankar <sibis@xxxxxxxxxxxxxx>
> ---
> 
> V5:
>  * Use dev_pm_opp_adjust_voltage instead [Viresh]
>  * Misc cleanup
> 
> v4:
>  * Split fast switch disable into another patch [Lukasz]
> 
>  drivers/cpufreq/qcom-cpufreq-hw.c | 77 ++++++++++++++++++++++++++++++-
>  1 file changed, 75 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
> index fc92a8842e252..fbd73d106a3ae 100644
> --- a/drivers/cpufreq/qcom-cpufreq-hw.c
> +++ b/drivers/cpufreq/qcom-cpufreq-hw.c
> @@ -6,6 +6,7 @@
>  #include <linux/bitfield.h>
>  #include <linux/cpufreq.h>
>  #include <linux/init.h>
> +#include <linux/interconnect.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/of_address.h>
> @@ -31,6 +32,52 @@
>  static unsigned long cpu_hw_rate, xo_rate;
>  static struct platform_device *global_pdev;
>  
> +static int qcom_cpufreq_set_bw(struct cpufreq_policy *policy,
> +			       unsigned long freq_khz)
> +{
> +	unsigned long freq_hz = freq_khz * 1000;
> +	struct dev_pm_opp *opp;
> +	struct device *dev;
> +	int ret;
> +
> +	dev = get_cpu_device(policy->cpu);
> +	if (!dev)
> +		return -ENODEV;
> +
> +	opp = dev_pm_opp_find_freq_exact(dev, freq_hz, true);
> +	if (IS_ERR(opp))
> +		return PTR_ERR(opp);
> +
> +	ret = dev_pm_opp_set_bw(dev, opp);
> +	dev_pm_opp_put(opp);
> +	return ret;
> +}
> +
> +static int qcom_cpufreq_update_opp(struct device *cpu_dev,
> +				   unsigned long freq_khz,
> +				   unsigned long volt)
> +{
> +	unsigned long freq_hz = freq_khz * 1000;
> +
> +	if (dev_pm_opp_adjust_voltage(cpu_dev, freq_hz, volt, volt, volt))
> +		return dev_pm_opp_add(cpu_dev, freq_hz, volt);

What's going on here ? Why add OPP here ?

> +
> +	/* Enable the opp after voltage update */
> +	return dev_pm_opp_enable(cpu_dev, freq_hz);
> +}
> +
> +/* Check for optional interconnect paths on CPU0 */
> +static int qcom_cpufreq_find_icc_paths(struct device *dev)
> +{
> +	struct device *cpu_dev;
> +
> +	cpu_dev = get_cpu_device(0);
> +	if (!cpu_dev)
> +		return -EPROBE_DEFER;
> +
> +	return dev_pm_opp_of_find_icc_paths(cpu_dev, NULL);
> +}
> +

open code this into the probe routine.

>  static int qcom_cpufreq_hw_target_index(struct cpufreq_policy *policy,
>  					unsigned int index)
>  {
> @@ -39,6 +86,8 @@ static int qcom_cpufreq_hw_target_index(struct cpufreq_policy *policy,
>  
>  	writel_relaxed(index, perf_state_reg);
>  
> +	qcom_cpufreq_set_bw(policy, freq);
> +
>  	arch_set_freq_scale(policy->related_cpus, freq,
>  			    policy->cpuinfo.max_freq);
>  	return 0;
> @@ -88,12 +137,30 @@ static int qcom_cpufreq_hw_read_lut(struct device *cpu_dev,
>  {
>  	u32 data, src, lval, i, core_count, prev_freq = 0, freq;
>  	u32 volt;
> +	u64 rate;
>  	struct cpufreq_frequency_table	*table;
> +	struct device_node *opp_table_np, *np;
> +	int ret;
>  
>  	table = kcalloc(LUT_MAX_ENTRIES + 1, sizeof(*table), GFP_KERNEL);
>  	if (!table)
>  		return -ENOMEM;
>  
> +	ret = dev_pm_opp_of_add_table(cpu_dev);
> +	if (!ret) {
> +		/* Disable all opps and cross-validate against LUT */
> +		opp_table_np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
> +		for_each_available_child_of_node(opp_table_np, np) {
> +			ret = of_property_read_u64(np, "opp-hz", &rate);

No way, please use dev_pm_opp_find_freq_*() here instead to grab OPPs
one by one.

> +			if (!ret)
> +				dev_pm_opp_disable(cpu_dev, rate);
> +		}
> +		of_node_put(opp_table_np);
> +	} else if (ret != -ENODEV) {
> +		dev_err(cpu_dev, "Invalid OPP table in Device tree\n");
> +		return ret;
> +	}

Rather put this in the if (ret) block and so the else part doesn't
need extra indentation.

> +
>  	for (i = 0; i < LUT_MAX_ENTRIES; i++) {
>  		data = readl_relaxed(base + REG_FREQ_LUT +
>  				      i * LUT_ROW_SIZE);
> @@ -112,7 +179,7 @@ static int qcom_cpufreq_hw_read_lut(struct device *cpu_dev,
>  
>  		if (freq != prev_freq && core_count != LUT_TURBO_IND) {
>  			table[i].frequency = freq;
> -			dev_pm_opp_add(cpu_dev, freq * 1000, volt);
> +			qcom_cpufreq_update_opp(cpu_dev, freq, volt);
>  			dev_dbg(cpu_dev, "index=%d freq=%d, core_count %d\n", i,
>  				freq, core_count);
>  		} else if (core_count == LUT_TURBO_IND) {
> @@ -133,7 +200,8 @@ static int qcom_cpufreq_hw_read_lut(struct device *cpu_dev,
>  			if (prev->frequency == CPUFREQ_ENTRY_INVALID) {
>  				prev->frequency = prev_freq;
>  				prev->flags = CPUFREQ_BOOST_FREQ;
> -				dev_pm_opp_add(cpu_dev,	prev_freq * 1000, volt);
> +				qcom_cpufreq_update_opp(cpu_dev, prev_freq,
> +							volt);
>  			}
>  
>  			break;

-- 
viresh