From: Viresh Kumar viresh.kumar@linaro.org

This patch adds IKS (In Kernel Switcher) support to cpufreq driver.

This creates a combined freq table for A7-A15 CPU pairs. A7 frequencies are virtualized and scaled down to half the actual frequencies to approximate a linear scale across the combined A7+A15 range. When the requested frequency change crosses the A7-A15 boundary a cluster switch is invoked.

Based on Earlier Work from Sudeep.

Signed-off-by: Sudeep KarkadaNagesha sudeep.karkadanagesha@arm.com Signed-off-by: Viresh Kumar viresh.kumar@linaro.org Signed-off-by: Nicolas Pitre nico@linaro.org --- drivers/cpufreq/arm_big_little.c | 363 ++++++++++++++++++++++++++++++++++++--- drivers/cpufreq/arm_big_little.h | 5 - 2 files changed, 337 insertions(+), 31 deletions(-)

diff --git a/drivers/cpufreq/arm_big_little.c b/drivers/cpufreq/arm_big_little.c index 163e3378fe..a6a8f74811 100644 --- a/drivers/cpufreq/arm_big_little.c +++ b/drivers/cpufreq/arm_big_little.c @@ -24,27 +24,165 @@ #include <linux/cpufreq.h> #include <linux/cpumask.h> #include <linux/export.h> +#include <linux/mutex.h> #include <linux/of_platform.h> #include <linux/pm_opp.h> #include <linux/slab.h> #include <linux/topology.h> #include <linux/types.h> +#include <asm/bL_switcher.h>

#include "arm_big_little.h"

/* Currently we support only two clusters */ +#define A15_CLUSTER 0 +#define A7_CLUSTER 1 #define MAX_CLUSTERS 2

+#ifdef CONFIG_BL_SWITCHER +#define is_bL_switching_enabled() true +#else +#define is_bL_switching_enabled() false +#endif + +#define ACTUAL_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq << 1 : freq) +#define VIRT_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq >> 1 : freq) + static struct cpufreq_arm_bL_ops *arm_bL_ops; static struct clk *clk[MAX_CLUSTERS]; -static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS]; -static atomic_t cluster_usage[MAX_CLUSTERS] = {ATOMIC_INIT(0), ATOMIC_INIT(0)}; +static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1]; +static atomic_t cluster_usage[MAX_CLUSTERS + 1]; + +static unsigned int clk_big_min; /* (Big) clock frequencies */ +static unsigned int clk_little_max; /* Maximum clock frequency (Little) */ + +static DEFINE_PER_CPU(unsigned int, physical_cluster); +static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq); + +static struct mutex cluster_lock[MAX_CLUSTERS]; + +static inline int raw_cpu_to_cluster(int cpu) +{ + return topology_physical_package_id(cpu); +} + +static inline int cpu_to_cluster(int cpu) +{ + return is_bL_switching_enabled() ? + MAX_CLUSTERS : raw_cpu_to_cluster(cpu); +} + +static unsigned int find_cluster_maxfreq(int cluster) +{ + int j; + u32 max_freq = 0, cpu_freq; + + for_each_online_cpu(j) { + cpu_freq = per_cpu(cpu_last_req_freq, j); + + if ((cluster == per_cpu(physical_cluster, j)) && + (max_freq < cpu_freq)) + max_freq = cpu_freq; + } + + pr_debug("%s: cluster: %d, max freq: %d\n", __func__, cluster, + max_freq); + + return max_freq; +} + +static unsigned int clk_get_cpu_rate(unsigned int cpu) +{ + u32 cur_cluster = per_cpu(physical_cluster, cpu); + u32 rate = clk_get_rate(clk[cur_cluster]) / 1000; + + /* For switcher we use virtual A7 clock rates */ + if (is_bL_switching_enabled()) + rate = VIRT_FREQ(cur_cluster, rate); + + pr_debug("%s: cpu: %d, cluster: %d, freq: %u\n", __func__, cpu, + cur_cluster, rate); + + return rate; +} + +static unsigned int bL_cpufreq_get_rate(unsigned int cpu) +{ + if (is_bL_switching_enabled()) { + pr_debug("%s: freq: %d\n", __func__, per_cpu(cpu_last_req_freq, + cpu)); + + return per_cpu(cpu_last_req_freq, cpu); + } else { + return clk_get_cpu_rate(cpu); + } +}

-static unsigned int bL_cpufreq_get(unsigned int cpu) +static unsigned int +bL_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate) { - u32 cur_cluster = cpu_to_cluster(cpu); + u32 new_rate, prev_rate; + int ret; + bool bLs = is_bL_switching_enabled(); + + mutex_lock(&cluster_lock[new_cluster]); + + if (bLs) { + prev_rate = per_cpu(cpu_last_req_freq, cpu); + per_cpu(cpu_last_req_freq, cpu) = rate; + per_cpu(physical_cluster, cpu) = new_cluster; + + new_rate = find_cluster_maxfreq(new_cluster); + new_rate = ACTUAL_FREQ(new_cluster, new_rate); + } else { + new_rate = 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; + } + + mutex_unlock(&cluster_lock[new_cluster]); + + /* 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", + __func__, cpu, old_cluster, new_cluster); + + /* Switch cluster */ + bL_switch_request(cpu, new_cluster); + + mutex_lock(&cluster_lock[old_cluster]);

- return clk_get_rate(clk[cur_cluster]) / 1000; + /* 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); + } + mutex_unlock(&cluster_lock[old_cluster]); + } + + return 0; }

/* Set clock frequency */ @@ -52,63 +190,164 @@ static int bL_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index) { struct cpufreq_freqs freqs; - u32 cpu = policy->cpu, cur_cluster; + u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster; int ret = 0;

- cur_cluster = cpu_to_cluster(policy->cpu); + cur_cluster = cpu_to_cluster(cpu); + new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);

- freqs.old = bL_cpufreq_get(policy->cpu); + freqs.old = bL_cpufreq_get_rate(cpu); freqs.new = freq_table[cur_cluster][index].frequency;

pr_debug("%s: cpu: %d, cluster: %d, oldfreq: %d, target freq: %d, new freq: %d\n", __func__, cpu, cur_cluster, freqs.old, freqs.new, freqs.new);

+ if (is_bL_switching_enabled()) { + if ((actual_cluster == A15_CLUSTER) && + (freqs.new < clk_big_min)) { + new_cluster = A7_CLUSTER; + } else if ((actual_cluster == A7_CLUSTER) && + (freqs.new > clk_little_max)) { + new_cluster = A15_CLUSTER; + } + } + cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);

- ret = clk_set_rate(clk[cur_cluster], freqs.new * 1000); - if (ret) { - pr_err("clk_set_rate failed: %d\n", ret); + ret = bL_cpufreq_set_rate(cpu, actual_cluster, new_cluster, freqs.new); + if (ret) freqs.new = freqs.old; - }

cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);

return ret; }

+static inline u32 get_table_count(struct cpufreq_frequency_table *table) +{ + int count; + + for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++) + ; + + return count; +} + +/* get the minimum frequency in the cpufreq_frequency_table */ +static inline u32 get_table_min(struct cpufreq_frequency_table *table) +{ + int i; + uint32_t min_freq = ~0; + for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) + if (table[i].frequency < min_freq) + min_freq = table[i].frequency; + return min_freq; +} + +/* get the maximum frequency in the cpufreq_frequency_table */ +static inline u32 get_table_max(struct cpufreq_frequency_table *table) +{ + int i; + uint32_t max_freq = 0; + for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) + if (table[i].frequency > max_freq) + max_freq = table[i].frequency; + return max_freq; +} + +static int merge_cluster_tables(void) +{ + int i, j, k = 0, count = 1; + struct cpufreq_frequency_table *table; + + for (i = 0; i < MAX_CLUSTERS; i++) + count += get_table_count(freq_table[i]); + + table = kzalloc(sizeof(*table) * count, GFP_KERNEL); + if (!table) + return -ENOMEM; + + freq_table[MAX_CLUSTERS] = table; + + /* Add in reverse order to get freqs in increasing order */ + for (i = MAX_CLUSTERS - 1; i >= 0; i--) { + for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END; + j++) { + table[k].frequency = VIRT_FREQ(i, + freq_table[i][j].frequency); + pr_debug("%s: index: %d, freq: %d\n", __func__, k, + table[k].frequency); + k++; + } + } + + table[k].driver_data = k; + table[k].frequency = CPUFREQ_TABLE_END; + + pr_debug("%s: End, table: %p, count: %d\n", __func__, table, k); + + return 0; +} + +static void _put_cluster_clk_and_freq_table(struct device *cpu_dev) +{ + u32 cluster = raw_cpu_to_cluster(cpu_dev->id); + + if (!freq_table[cluster]) + return; + + clk_put(clk[cluster]); + dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]); + dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster); +} + static void put_cluster_clk_and_freq_table(struct device *cpu_dev) { u32 cluster = cpu_to_cluster(cpu_dev->id); + int i; + + if (atomic_dec_return(&cluster_usage[cluster])) + return; + + if (cluster < MAX_CLUSTERS) + return _put_cluster_clk_and_freq_table(cpu_dev);

- if (!atomic_dec_return(&cluster_usage[cluster])) { - clk_put(clk[cluster]); - dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]); - dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster); + for_each_present_cpu(i) { + struct device *cdev = get_cpu_device(i); + if (!cdev) { + pr_err("%s: failed to get cpu%d device\n", __func__, i); + return; + } + + _put_cluster_clk_and_freq_table(cdev); } + + /* free virtual table */ + kfree(freq_table[cluster]); }

-static int get_cluster_clk_and_freq_table(struct device *cpu_dev) +static int _get_cluster_clk_and_freq_table(struct device *cpu_dev) { - u32 cluster = cpu_to_cluster(cpu_dev->id); + u32 cluster = raw_cpu_to_cluster(cpu_dev->id); char name[14] = "cpu-cluster."; int ret;

- if (atomic_inc_return(&cluster_usage[cluster]) != 1) + if (freq_table[cluster]) return 0;

ret = arm_bL_ops->init_opp_table(cpu_dev); if (ret) { dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n", __func__, cpu_dev->id, ret); - goto atomic_dec; + goto out; }

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", __func__, cpu_dev->id, ret); - goto atomic_dec; + goto out; }

name[12] = cluster + '0'; @@ -125,13 +364,72 @@ static int get_cluster_clk_and_freq_table(struct device *cpu_dev) ret = PTR_ERR(clk[cluster]); dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);

-atomic_dec: - atomic_dec(&cluster_usage[cluster]); +out: dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__, cluster); return ret; }

+static int get_cluster_clk_and_freq_table(struct device *cpu_dev) +{ + u32 cluster = cpu_to_cluster(cpu_dev->id); + int i, ret; + + if (atomic_inc_return(&cluster_usage[cluster]) != 1) + return 0; + + if (cluster < MAX_CLUSTERS) { + ret = _get_cluster_clk_and_freq_table(cpu_dev); + if (ret) + atomic_dec(&cluster_usage[cluster]); + return ret; + } + + /* + * Get data for all clusters and fill virtual cluster with a merge of + * both + */ + for_each_present_cpu(i) { + struct device *cdev = get_cpu_device(i); + if (!cdev) { + pr_err("%s: failed to get cpu%d device\n", __func__, i); + return -ENODEV; + } + + ret = _get_cluster_clk_and_freq_table(cdev); + if (ret) + goto put_clusters; + } + + ret = merge_cluster_tables(); + if (ret) + goto put_clusters; + + /* Assuming 2 cluster, set clk_big_min and clk_little_max */ + clk_big_min = get_table_min(freq_table[0]); + clk_little_max = VIRT_FREQ(1, get_table_max(freq_table[1])); + + pr_debug("%s: cluster: %d, clk_big_min: %d, clk_little_max: %d\n", + __func__, cluster, clk_big_min, clk_little_max); + + return 0; + +put_clusters: + for_each_present_cpu(i) { + struct device *cdev = get_cpu_device(i); + if (!cdev) { + pr_err("%s: failed to get cpu%d device\n", __func__, i); + return -ENODEV; + } + + _put_cluster_clk_and_freq_table(cdev); + } + + atomic_dec(&cluster_usage[cluster]); + + return ret; +} + /* Per-CPU initialization */ static int bL_cpufreq_init(struct cpufreq_policy *policy) { @@ -158,13 +456,23 @@ static int bL_cpufreq_init(struct cpufreq_policy *policy) return ret; }

+ if (cur_cluster < MAX_CLUSTERS) { + cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu)); + + per_cpu(physical_cluster, policy->cpu) = cur_cluster; + } else { + /* Assumption: during init, we are always running on A15 */ + per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER; + } + if (arm_bL_ops->get_transition_latency) policy->cpuinfo.transition_latency = arm_bL_ops->get_transition_latency(cpu_dev); else policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;

- cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu)); + if (is_bL_switching_enabled()) + per_cpu(cpu_last_req_freq, policy->cpu) = clk_get_cpu_rate;

dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu); return 0; @@ -194,7 +502,7 @@ static struct cpufreq_driver bL_cpufreq_driver = { CPUFREQ_HAVE_GOVERNOR_PER_POLICY, .verify = cpufreq_generic_frequency_table_verify, .target_index = bL_cpufreq_set_target, - .get = bL_cpufreq_get, + .get = bL_cpufreq_get_rate, .init = bL_cpufreq_init, .exit = bL_cpufreq_exit, .attr = cpufreq_generic_attr, @@ -202,7 +510,7 @@ static struct cpufreq_driver bL_cpufreq_driver = {

int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops) { - int ret; + int ret, i;

if (arm_bL_ops) { pr_debug("%s: Already registered: %s, exiting\n", __func__, @@ -217,6 +525,9 @@ int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)

arm_bL_ops = ops;

+ for (i = 0; i < MAX_CLUSTERS; i++) + mutex_init(&cluster_lock[i]); + ret = cpufreq_register_driver(&bL_cpufreq_driver); if (ret) { pr_info("%s: Failed registering platform driver: %s, err: %d\n", diff --git a/drivers/cpufreq/arm_big_little.h b/drivers/cpufreq/arm_big_little.h index 79b2ce1788..70f18fc12d 100644 --- a/drivers/cpufreq/arm_big_little.h +++ b/drivers/cpufreq/arm_big_little.h @@ -34,11 +34,6 @@ struct cpufreq_arm_bL_ops { int (*init_opp_table)(struct device *cpu_dev); };

-static inline int cpu_to_cluster(int cpu) -{ - return topology_physical_package_id(cpu); -} - int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops); void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops);