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SubjectRe: [PATCH 1/8] cpufreq: arm_big_little: add cluster regulator support
Hi Bartlomiej,

> Add cluster regulator support as a preparation to adding
> generic arm_big_little_dt cpufreq_dt driver support for
> ODROID-XU3 board. This allows arm_big_little[_dt] driver
> to set not only the frequency but also the voltage (which
> is obtained from operating point's voltage value) for CPU
> clusters.
>
> Cc: Kukjin Kim <kgene.kim@samsung.com>
> Cc: Doug Anderson <dianders@chromium.org>
> Cc: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
> Cc: Andreas Faerber <afaerber@suse.de>
> Cc: Sachin Kamat <sachin.kamat@linaro.org>
> Cc: Thomas Abraham <thomas.ab@samsung.com>
> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
> ---
> .../bindings/cpufreq/arm_big_little_dt.txt | 4 +
> drivers/cpufreq/arm_big_little.c | 153
> +++++++++++++++++--- 2 files changed, 139 insertions(+), 18
> deletions(-)
>
> diff --git
> a/Documentation/devicetree/bindings/cpufreq/arm_big_little_dt.txt
> b/Documentation/devicetree/bindings/cpufreq/arm_big_little_dt.txt
> index 0715695..8ca4a12 100644 ---
> a/Documentation/devicetree/bindings/cpufreq/arm_big_little_dt.txt +++
> b/Documentation/devicetree/bindings/cpufreq/arm_big_little_dt.txt @@
> -18,6 +18,10 @@ Required properties: Optional properties:
> - clock-latency: Specify the possible maximum transition latency for
> clock, in unit of nanoseconds.
> +- cpu-cluster.0-supply: Provides the regulator node supplying
> voltage to CPU
> + cluster 0.
> +- cpu-cluster.1-supply: Provides the regulator node supplying
> voltage to CPU
> + cluster 1.
>
> Examples:
>
> diff --git a/drivers/cpufreq/arm_big_little.c
> b/drivers/cpufreq/arm_big_little.c index e1a6ba6..edb461b 100644
> --- a/drivers/cpufreq/arm_big_little.c
> +++ b/drivers/cpufreq/arm_big_little.c
> @@ -31,6 +31,7 @@
> #include <linux/slab.h>
> #include <linux/topology.h>
> #include <linux/types.h>
> +#include <linux/regulator/consumer.h>
> #include <asm/bL_switcher.h>
>
> #include "arm_big_little.h"
> @@ -54,6 +55,9 @@ static bool bL_switching_enabled;
>
> static struct cpufreq_arm_bL_ops *arm_bL_ops;
> static struct clk *clk[MAX_CLUSTERS];
> +static struct regulator *reg[MAX_CLUSTERS];
> +static struct device *cpu_devs[MAX_CLUSTERS];
> +static int transition_latencies[MAX_CLUSTERS];
> static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1];
> static atomic_t cluster_usage[MAX_CLUSTERS + 1];
>
> @@ -122,7 +126,76 @@ static unsigned int bL_cpufreq_get_rate(unsigned
> int cpu) }
> }
>
> -static unsigned int
> +static int
> +bL_cpufreq_set_rate_cluster(u32 cpu, u32 cluster, u32 new_rate)
> +{
> + unsigned long volt = 0, volt_old = 0;
> + long freq_Hz;
> + u32 old_rate;
> + int ret;
> +
> + freq_Hz = new_rate * 1000;
> + old_rate = clk_get_rate(clk[cluster]) / 1000;
> +
> + if (!IS_ERR(reg[cluster])) {
> + struct dev_pm_opp *opp;
> + unsigned long opp_freq;
> +
> + rcu_read_lock();
> + opp = dev_pm_opp_find_freq_ceil(cpu_devs[cluster],
> &freq_Hz);
> + if (IS_ERR(opp)) {
> + rcu_read_unlock();
> + pr_err("%s: cpu %d, cluster: %d, failed to
> find OPP for %ld\n",
> + __func__, cpu, cluster, freq_Hz);
> + return PTR_ERR(opp);
> + }
> + volt = dev_pm_opp_get_voltage(opp);
> + opp_freq = dev_pm_opp_get_freq(opp);
> + rcu_read_unlock();
> + volt_old = regulator_get_voltage(reg[cluster]);
> + pr_debug("%s: cpu %d, cluster: %d, Found OPP: %ld
> kHz, %ld uV\n",
> + __func__, cpu, cluster, opp_freq / 1000,
> volt);
> + }
> +
> + pr_debug("%s: cpu %d, cluster: %d, %u MHz, %ld mV --> %u
> MHz, %ld mV\n",
> + __func__, cpu, cluster,
> + old_rate / 1000, (volt_old > 0) ? volt_old / 1000 :
> -1,
> + new_rate / 1000, volt ? volt / 1000 : -1);
> +
> + /* scaling up? scale voltage before frequency */
> + if (!IS_ERR(reg[cluster]) && new_rate > old_rate) {
> + ret = regulator_set_voltage_tol(reg[cluster], volt,
> 0);
> + if (ret) {
> + pr_err("%s: cpu: %d, cluster: %d, failed to
> scale voltage up: %d\n",
> + __func__, cpu, cluster, ret);
> + return ret;
> + }
> + }
> +
> + ret = clk_set_rate(clk[cluster], new_rate * 1000);
> + if (WARN_ON(ret)) {
> + pr_err("%s: clk_set_rate failed: %d, cluster: %d\n",
> + __func__, cluster, ret);
> + if (!IS_ERR(reg[cluster]) && volt_old > 0)
> + regulator_set_voltage_tol(reg[cluster],
> volt_old, 0);
> + return ret;
> + }
> +
> + /* scaling down? scale voltage after frequency */
> + if (!IS_ERR(reg[cluster]) && new_rate < old_rate) {
> + ret = regulator_set_voltage_tol(reg[cluster], volt,
> 0);
> + if (ret) {
> + pr_err("%s: cpu: %d, cluster: %d, failed to
> scale voltage down: %d\n",
> + __func__, cpu, cluster, ret);
> + clk_set_rate(clk[cluster], old_rate * 1000);
> + return ret;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static int
> bL_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32
> rate) {
> u32 new_rate, prev_rate;
> @@ -145,22 +218,17 @@ bL_cpufreq_set_rate(u32 cpu, u32 old_cluster,
> u32 new_cluster, u32 rate) pr_debug("%s: cpu: %d, old cluster: %d,
> new cluster: %d, freq: %d\n", __func__, cpu, old_cluster,
> new_cluster, new_rate);
> - ret = clk_set_rate(clk[new_cluster], new_rate * 1000);
> - if (WARN_ON(ret)) {
> - pr_err("clk_set_rate failed: %d, new cluster: %d\n",
> ret,
> - new_cluster);
> - if (bLs) {
> - per_cpu(cpu_last_req_freq, cpu) = prev_rate;
> - per_cpu(physical_cluster, cpu) = old_cluster;
> - }
> -
> - mutex_unlock(&cluster_lock[new_cluster]);
> -
> - return ret;
> + ret = bL_cpufreq_set_rate_cluster(cpu, new_cluster,
> new_rate);
> + if (ret && bLs) {
> + per_cpu(cpu_last_req_freq, cpu) = prev_rate;
> + per_cpu(physical_cluster, cpu) = old_cluster;
> }
>
> mutex_unlock(&cluster_lock[new_cluster]);
>
> + if (ret)
> + return ret;
> +
> /* Recalc freq for old cluster when switching clusters */
> if (old_cluster != new_cluster) {
> pr_debug("%s: cpu: %d, old cluster: %d, new cluster:
> %d\n", @@ -174,14 +242,11 @@ bL_cpufreq_set_rate(u32 cpu, u32
> old_cluster, u32 new_cluster, u32 rate) /* Set freq of old cluster if
> there are cpus left on it */ new_rate =
> find_cluster_maxfreq(old_cluster); new_rate =
> ACTUAL_FREQ(old_cluster, new_rate); -
> if (new_rate) {
> pr_debug("%s: Updating rate of old cluster:
> %d, to freq: %d\n", __func__, old_cluster, new_rate);
>
> - if (clk_set_rate(clk[old_cluster], new_rate
> * 1000))
> - pr_err("%s: clk_set_rate failed: %d,
> old cluster: %d\n",
> - __func__, ret,
> old_cluster);
> + bL_cpufreq_set_rate_cluster(cpu,
> old_cluster, new_rate); }
> mutex_unlock(&cluster_lock[old_cluster]);
> }
> @@ -288,6 +353,8 @@ static void
> _put_cluster_clk_and_freq_table(struct device *cpu_dev) return;
>
> clk_put(clk[cluster]);
> + if (!IS_ERR(reg[cluster]))
> + regulator_put(reg[cluster]);
> dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
> if (arm_bL_ops->free_opp_table)
> arm_bL_ops->free_opp_table(cpu_dev);
> @@ -321,6 +388,7 @@ static void put_cluster_clk_and_freq_table(struct
> device *cpu_dev)
> static int _get_cluster_clk_and_freq_table(struct device *cpu_dev)
> {
> + unsigned long min_uV = ~0, max_uV = 0;
> u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
> char name[14] = "cpu-cluster.";
> int ret;
> @@ -335,6 +403,51 @@ static int
> _get_cluster_clk_and_freq_table(struct device *cpu_dev) goto out;
> }
>
> + name[12] = cluster + '0';
> + reg[cluster] = regulator_get_optional(cpu_dev, name);
> + if (!IS_ERR(reg[cluster])) {
> + unsigned long opp_freq = 0;
> +
> + dev_dbg(cpu_dev, "%s: reg: %p, cluster: %d\n",
> + __func__, reg[cluster], cluster);
> + cpu_devs[cluster] = cpu_dev;
> +
> + /*
> + * Disable any OPPs where the connected regulator
> isn't able to
> + * provide the specified voltage and record minimum
> and maximum
> + * voltage levels.
> + */
> + while (1) {
> + struct dev_pm_opp *opp;
> + unsigned long opp_uV;
> +
> + rcu_read_lock();
> + opp = dev_pm_opp_find_freq_ceil(cpu_dev,
> &opp_freq);
> + if (IS_ERR(opp)) {
> + rcu_read_unlock();
> + break;
> + }
> + opp_uV = dev_pm_opp_get_voltage(opp);
> + rcu_read_unlock();
> +
> + if
> (regulator_is_supported_voltage(reg[cluster], opp_uV,
> + opp_uV)) {
> + if (opp_uV < min_uV)
> + min_uV = opp_uV;
> + if (opp_uV > max_uV)
> + max_uV = opp_uV;
> + } else {
> + dev_pm_opp_disable(cpu_dev,
> opp_freq);
> + }
> +
> + opp_freq++;
> + }
> +
> + ret = regulator_set_voltage_time(reg[cluster],
> min_uV, max_uV);
> + if (ret > 0)
> + transition_latencies[cluster] = ret * 1000;
> + }
> +
> ret = dev_pm_opp_init_cpufreq_table(cpu_dev,
> &freq_table[cluster]); if (ret) {
> dev_err(cpu_dev, "%s: failed to init cpufreq table,
> cpu: %d, err: %d\n", @@ -342,7 +455,6 @@ static int
> _get_cluster_clk_and_freq_table(struct device *cpu_dev) goto
> free_opp_table; }
>
> - name[12] = cluster + '0';
> clk[cluster] = clk_get(cpu_dev, name);
> if (!IS_ERR(clk[cluster])) {
> dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p,
> cluster: %d\n", @@ -469,6 +581,11 @@ static int
> bL_cpufreq_init(struct cpufreq_policy *policy) else
> policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
>
> + if (cur_cluster < MAX_CLUSTERS &&
> + policy->cpuinfo.transition_latency != CPUFREQ_ETERNAL)
> + policy->cpuinfo.transition_latency
> + += transition_latencies[cur_cluster];
> +
> if (is_bL_switching_enabled())
> per_cpu(cpu_last_req_freq, policy->cpu) =
> clk_get_cpu_rate(policy->cpu);

Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>

--
Best regards,

Lukasz Majewski

Samsung R&D Institute Poland (SRPOL) | Linux Platform Group


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