Re: [RFC v3 08/10] cpufreq: qcom: Update the bandwidth levels on frequency change

[Lukasz Luba <lukasz.luba@arm.com>]

Hi Sibi,

On 1/27/20 8:03 PM, Sibi Sankar wrote:
> Add support to parse and update OPP tables attached to the cpu device
> when the required OPP bandwidth values are populated to enable scaling
> of DDR/L3 bandwidth levels with frequency change.
> 
> Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
> ---
>   drivers/cpufreq/qcom-cpufreq-hw.c | 246 +++++++++++++++++++++++++++---
>   1 file changed, 225 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
> index fc92a8842e252..348eb2fdaccaf 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>
> @@ -28,17 +29,194 @@
>   #define REG_VOLT_LUT			0x114
>   #define REG_PERF_STATE			0x920
>   
> +#define QCOM_ICC_TAG_ACTIVE_ONLY	1
> +
>   static unsigned long cpu_hw_rate, xo_rate;
>   static struct platform_device *global_pdev;
>   
> +/* opp table indices */
> +enum {
> +	QCOM_CPU_OPP_TABLE_INDEX,
> +	QCOM_CPU_DDR_OPP_TABLE_INDEX,
> +	QCOM_CPU_L3_OPP_TABLE_INDEX,
> +};
> +
> +/* icc path indices */
> +enum {
> +	ICC_DDR_PATH,
> +	ICC_L3_PATH,
> +};
> +
> +struct qcom_cpufreq_hw_res {
> +	void __iomem *base;
> +
> +	struct device *cpu_dev;
> +
> +	/* ddr/l3 icc paths */
> +	struct icc_path *path[2];
> +
> +	/* cpu/ddr/l3 opp tables */
> +	struct opp_table *opp_table[3];
> +};
> +
> +struct cpufreq_hw_icc_info {
> +	const char *icc_path_name;
> +	u8 table_index;
> +	u32 tag;
> +};
> +
> +static const struct cpufreq_hw_icc_info icc_info[] = {
> +	{
> +		.icc_path_name = "cpu-ddr",
> +		.table_index = QCOM_CPU_DDR_OPP_TABLE_INDEX,
> +		.tag = QCOM_ICC_TAG_ACTIVE_ONLY,
> +	},
> +	{
> +		.icc_path_name = "cpu-l3",
> +		.table_index = QCOM_CPU_L3_OPP_TABLE_INDEX,
> +		.tag = 0,
> +	},
> +};
> +
> +static int qcom_cpufreq_hw_add_opp_table(struct qcom_cpufreq_hw_res *res)
> +{
> +	struct opp_table **table = res->opp_table;
> +	struct device_node *opp_table_np, *np;
> +	struct device *dev = res->cpu_dev;
> +	int ret, i;
> +	u64 rate;
> +
> +	for (i = 0; i <= QCOM_CPU_L3_OPP_TABLE_INDEX; i++) {
> +		ret = dev_pm_opp_of_add_table_indexed(dev, i);
> +		if (ret) {
> +			dev_dbg(dev, "Add OPP table failed index %d: %d\n",
> +				i, ret);
> +			goto err;
> +		}
> +
> +		table[i] = dev_pm_opp_get_opp_table_indexed(dev, i);
> +		if (!table[i]) {
> +			dev_dbg(dev, "Get OPP table failed index %d\n", i);
> +			ret = -EINVAL;
> +			goto err;
> +		}
> +	}
> +
> +	/* Disable all cpu opps and cross-validate against LUT */
> +	opp_table_np = dev_pm_opp_of_get_opp_desc_node(dev);
> +	for_each_available_child_of_node(opp_table_np, np) {
> +		ret = of_property_read_u64(np, "opp-hz", &rate);
> +		if (ret)
> +			continue;
> +
> +		dev_pm_opp_disable(dev, rate);
> +	}
> +	of_node_put(opp_table_np);
> +
> +	return 0;
> +
> +err:
> +	for (; i >= 0; i--) {
> +		if (table[i]) {
> +			dev_pm_opp_put_opp_table(table[i]);
> +			table[i] = NULL;
> +		}
> +	}
> +
> +	dev_pm_opp_remove_table(dev);
> +	return ret;
> +}
> +
> +static int qcom_cpufreq_hw_icc_init(struct qcom_cpufreq_hw_res *res, u8 index)
> +{
> +	const struct cpufreq_hw_icc_info *info = &icc_info[index];
> +	struct icc_path **path = res->path;
> +	struct device *dev = res->cpu_dev;
> +
> +	path[index] = of_icc_get(dev, info->icc_path_name);
> +	if (IS_ERR(path[index])) {
> +		dev_dbg(dev, "ICC %s path get failed ret: %ld\n",
> +			info->icc_path_name, PTR_ERR(path[index]));
> +		return PTR_ERR(path[index]);
> +	}
> +
> +	icc_set_tag(path[index], info->tag);
> +
> +	return 0;
> +}
> +
> +static void qcom_cpufreq_hw_icc_set(struct qcom_cpufreq_hw_res *res,
> +				    unsigned long freq)
> +{
> +	struct opp_table **table = res->opp_table;
> +	const struct cpufreq_hw_icc_info *info;
> +	unsigned long freq_hz = freq * 1000;
> +	struct icc_path **path = res->path;
> +	struct device *dev = res->cpu_dev;
> +	struct dev_pm_opp *cpu_opp, *opp;
> +	struct opp_table *cpu_opp_table;
> +	unsigned long peak_bw, avg_bw;
> +	int ret;
> +	int i;
> +
> +	cpu_opp_table = table[QCOM_CPU_OPP_TABLE_INDEX];
> +	if (!cpu_opp_table)
> +		return;
> +
> +	cpu_opp = dev_pm_opp_find_freq_exact(dev, freq_hz, true);
> +	if (IS_ERR_OR_NULL(cpu_opp))
> +		return;
> +
> +	for (i = 0; i <= ICC_L3_PATH; i++) {
> +		if (IS_ERR(path[i])) {
> +			if (PTR_ERR(path[i]) != -EPROBE_DEFER)
> +				continue;
> +
> +			ret = qcom_cpufreq_hw_icc_init(res, i);
> +			if (ret)
> +				continue;
> +		}
> +
> +		info = &icc_info[i];
> +
> +		opp = dev_pm_opp_xlate_required_opp(cpu_opp_table,
> +						    table[info->table_index],
> +						    cpu_opp);
> +		if (IS_ERR_OR_NULL(opp))
> +			continue;
> +
> +		peak_bw = dev_pm_opp_get_bw(opp, &avg_bw);
> +		dev_pm_opp_put(opp);
> +
> +		icc_set_bw(res->path[i], avg_bw, peak_bw);
> +	}
> +	dev_pm_opp_put(cpu_opp);
> +}
> +
> +static int qcom_cpufreq_update_opp(struct device *dev,
> +				   unsigned long freq_khz,
> +				   unsigned long volt)
> +{
> +	unsigned long freq_hz = freq_khz * 1000;
> +
> +	if (dev_pm_opp_update_voltage(dev, freq_hz, volt))
> +		return dev_pm_opp_add(dev, freq_hz, volt);
> +
> +	/* Enable the opp after voltage update*/
> +	return dev_pm_opp_enable(dev, freq_hz);
> +}
> +
>   static int qcom_cpufreq_hw_target_index(struct cpufreq_policy *policy,
>   					unsigned int index)
>   {
> -	void __iomem *perf_state_reg = policy->driver_data;
> +	struct qcom_cpufreq_hw_res *res = policy->driver_data;
> +	void __iomem *perf_state_reg = res->base + REG_PERF_STATE;
>   	unsigned long freq = policy->freq_table[index].frequency;
>   
>   	writel_relaxed(index, perf_state_reg);
>   
> +	qcom_cpufreq_hw_icc_set(res, freq);
> +
>   	arch_set_freq_scale(policy->related_cpus, freq,
>   			    policy->cpuinfo.max_freq);
>   	return 0;
> @@ -46,6 +224,7 @@ static int qcom_cpufreq_hw_target_index(struct cpufreq_policy *policy,
>   
>   static unsigned int qcom_cpufreq_hw_get(unsigned int cpu)
>   {
> +	struct qcom_cpufreq_hw_res *res;
>   	void __iomem *perf_state_reg;
>   	struct cpufreq_policy *policy;
>   	unsigned int index;
> @@ -54,7 +233,8 @@ static unsigned int qcom_cpufreq_hw_get(unsigned int cpu)
>   	if (!policy)
>   		return 0;
>   
> -	perf_state_reg = policy->driver_data;
> +	res = policy->driver_data;
> +	perf_state_reg = res->base + REG_PERF_STATE;
>   
>   	index = readl_relaxed(perf_state_reg);
>   	index = min(index, LUT_MAX_ENTRIES - 1);
> @@ -65,7 +245,8 @@ static unsigned int qcom_cpufreq_hw_get(unsigned int cpu)
>   static unsigned int qcom_cpufreq_hw_fast_switch(struct cpufreq_policy *policy,
>   						unsigned int target_freq)
>   {
> -	void __iomem *perf_state_reg = policy->driver_data;
> +	struct qcom_cpufreq_hw_res *res = policy->driver_data;
> +	void __iomem *perf_state_reg = res->base + REG_PERF_STATE;
>   	int index;
>   	unsigned long freq;
>   
> @@ -82,18 +263,24 @@ static unsigned int qcom_cpufreq_hw_fast_switch(struct cpufreq_policy *policy,
>   	return freq;
>   }
>   
> -static int qcom_cpufreq_hw_read_lut(struct device *cpu_dev,
> -				    struct cpufreq_policy *policy,
> -				    void __iomem *base)
> +static int qcom_cpufreq_hw_read_lut(struct cpufreq_policy *policy,
> +				    struct qcom_cpufreq_hw_res *res)
>   {
>   	u32 data, src, lval, i, core_count, prev_freq = 0, freq;
>   	u32 volt;
>   	struct cpufreq_frequency_table	*table;
> +	struct device *cpu_dev = res->cpu_dev;
> +	void __iomem *base = res->base;
> +	int ret;
>   
>   	table = kcalloc(LUT_MAX_ENTRIES + 1, sizeof(*table), GFP_KERNEL);
>   	if (!table)
>   		return -ENOMEM;
>   
> +	ret = qcom_cpufreq_hw_add_opp_table(res);
> +	if (ret)
> +		dev_dbg(cpu_dev, "Add OPP tables failed from dt\n");
> +
>   	for (i = 0; i < LUT_MAX_ENTRIES; i++) {
>   		data = readl_relaxed(base + REG_FREQ_LUT +
>   				      i * LUT_ROW_SIZE);
> @@ -112,7 +299,7 @@ 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 +320,8 @@ 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;
> @@ -175,11 +363,10 @@ static void qcom_get_related_cpus(int index, struct cpumask *m)
>   static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
>   {
>   	struct device *dev = &global_pdev->dev;
> +	struct qcom_cpufreq_hw_res *res;
>   	struct of_phandle_args args;
>   	struct device_node *cpu_np;
>   	struct device *cpu_dev;
> -	struct resource *res;
> -	void __iomem *base;
>   	int ret, index;
>   
>   	cpu_dev = get_cpu_device(policy->cpu);
> @@ -201,16 +388,17 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
>   
>   	index = args.args[0];
>   
> -	res = platform_get_resource(global_pdev, IORESOURCE_MEM, index);
> +	res = devm_kzalloc(dev, sizeof(*res), GFP_KERNEL);
>   	if (!res)
> -		return -ENODEV;
> -
> -	base = devm_ioremap(dev, res->start, resource_size(res));
> -	if (!base)
>   		return -ENOMEM;
>   
> +	res->cpu_dev = cpu_dev;
> +	res->base = devm_platform_ioremap_resource(global_pdev, index);
> +	if (IS_ERR(res->base))
> +		return PTR_ERR(res->base);
> +
>   	/* HW should be in enabled state to proceed */
> -	if (!(readl_relaxed(base + REG_ENABLE) & 0x1)) {
> +	if (!(readl_relaxed(res->base + REG_ENABLE) & 0x1)) {
>   		dev_err(dev, "Domain-%d cpufreq hardware not enabled\n", index);
>   		ret = -ENODEV;
>   		goto error;
> @@ -223,9 +411,9 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
>   		goto error;
>   	}
>   
> -	policy->driver_data = base + REG_PERF_STATE;
> +	policy->driver_data = res;
>   
> -	ret = qcom_cpufreq_hw_read_lut(cpu_dev, policy, base);
> +	ret = qcom_cpufreq_hw_read_lut(policy, res);
>   	if (ret) {
>   		dev_err(dev, "Domain-%d failed to read LUT\n", index);
>   		goto error;
> @@ -240,22 +428,38 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
>   
>   	dev_pm_opp_of_register_em(policy->cpus);
>   
> -	policy->fast_switch_possible = true;
> +	if (!res->opp_table[QCOM_CPU_OPP_TABLE_INDEX]) {
> +		policy->fast_switch_possible = true;
> +	} else {
> +		qcom_cpufreq_hw_icc_init(res, ICC_DDR_PATH);
> +		qcom_cpufreq_hw_icc_init(res, ICC_L3_PATH);
> +	}

This patch tries to disable silently the fast_switch. The fast_switch
is used by SchedUtil governor.

Regards,
Lukasz

>   
>   	return 0;
>   error:
> -	devm_iounmap(dev, base);
> +	devm_iounmap(dev, res->base);
> +	devm_kfree(&global_pdev->dev, res);
>   	return ret;
>   }
>   
>   static int qcom_cpufreq_hw_cpu_exit(struct cpufreq_policy *policy)
>   {
> +	struct qcom_cpufreq_hw_res *res = policy->driver_data;
>   	struct device *cpu_dev = get_cpu_device(policy->cpu);
> -	void __iomem *base = policy->driver_data - REG_PERF_STATE;
> +	struct opp_table **table = res->opp_table;
> +	void __iomem *base = res->base;
> +	int i;
> +
> +	for (i = 0; i <= QCOM_CPU_L3_OPP_TABLE_INDEX; i++) {
> +		if (table[i])
> +			dev_pm_opp_put_opp_table(table[i]);
> +	}
>   
>   	dev_pm_opp_remove_all_dynamic(cpu_dev);
>   	kfree(policy->freq_table);
> +	dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
>   	devm_iounmap(&global_pdev->dev, base);
> +	devm_kfree(&global_pdev->dev, res);
>   
>   	return 0;
>   }
>