diff options
Diffstat (limited to 'drivers/cpufreq/apple-soc-cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/apple-soc-cpufreq.c | 352 |
1 files changed, 352 insertions, 0 deletions
diff --git a/drivers/cpufreq/apple-soc-cpufreq.c b/drivers/cpufreq/apple-soc-cpufreq.c new file mode 100644 index 000000000000..d1801281cdd9 --- /dev/null +++ b/drivers/cpufreq/apple-soc-cpufreq.c @@ -0,0 +1,352 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Apple SoC CPU cluster performance state driver + * + * Copyright The Asahi Linux Contributors + * + * Based on scpi-cpufreq.c + */ + +#include <linux/bitfield.h> +#include <linux/bitops.h> +#include <linux/cpu.h> +#include <linux/cpufreq.h> +#include <linux/cpumask.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/pm_opp.h> +#include <linux/slab.h> + +#define APPLE_DVFS_CMD 0x20 +#define APPLE_DVFS_CMD_BUSY BIT(31) +#define APPLE_DVFS_CMD_SET BIT(25) +#define APPLE_DVFS_CMD_PS2 GENMASK(16, 12) +#define APPLE_DVFS_CMD_PS1 GENMASK(4, 0) + +/* Same timebase as CPU counter (24MHz) */ +#define APPLE_DVFS_LAST_CHG_TIME 0x38 + +/* + * Apple ran out of bits and had to shift this in T8112... + */ +#define APPLE_DVFS_STATUS 0x50 +#define APPLE_DVFS_STATUS_CUR_PS_T8103 GENMASK(7, 4) +#define APPLE_DVFS_STATUS_CUR_PS_SHIFT_T8103 4 +#define APPLE_DVFS_STATUS_TGT_PS_T8103 GENMASK(3, 0) +#define APPLE_DVFS_STATUS_CUR_PS_T8112 GENMASK(9, 5) +#define APPLE_DVFS_STATUS_CUR_PS_SHIFT_T8112 5 +#define APPLE_DVFS_STATUS_TGT_PS_T8112 GENMASK(4, 0) + +/* + * Div is +1, base clock is 12MHz on existing SoCs. + * For documentation purposes. We use the OPP table to + * get the frequency. + */ +#define APPLE_DVFS_PLL_STATUS 0xc0 +#define APPLE_DVFS_PLL_FACTOR 0xc8 +#define APPLE_DVFS_PLL_FACTOR_MULT GENMASK(31, 16) +#define APPLE_DVFS_PLL_FACTOR_DIV GENMASK(15, 0) + +#define APPLE_DVFS_TRANSITION_TIMEOUT 100 + +struct apple_soc_cpufreq_info { + u64 max_pstate; + u64 cur_pstate_mask; + u64 cur_pstate_shift; +}; + +struct apple_cpu_priv { + struct device *cpu_dev; + void __iomem *reg_base; + const struct apple_soc_cpufreq_info *info; +}; + +static struct cpufreq_driver apple_soc_cpufreq_driver; + +static const struct apple_soc_cpufreq_info soc_t8103_info = { + .max_pstate = 15, + .cur_pstate_mask = APPLE_DVFS_STATUS_CUR_PS_T8103, + .cur_pstate_shift = APPLE_DVFS_STATUS_CUR_PS_SHIFT_T8103, +}; + +static const struct apple_soc_cpufreq_info soc_t8112_info = { + .max_pstate = 31, + .cur_pstate_mask = APPLE_DVFS_STATUS_CUR_PS_T8112, + .cur_pstate_shift = APPLE_DVFS_STATUS_CUR_PS_SHIFT_T8112, +}; + +static const struct apple_soc_cpufreq_info soc_default_info = { + .max_pstate = 15, + .cur_pstate_mask = 0, /* fallback */ +}; + +static const struct of_device_id apple_soc_cpufreq_of_match[] = { + { + .compatible = "apple,t8103-cluster-cpufreq", + .data = &soc_t8103_info, + }, + { + .compatible = "apple,t8112-cluster-cpufreq", + .data = &soc_t8112_info, + }, + { + .compatible = "apple,cluster-cpufreq", + .data = &soc_default_info, + }, + {} +}; + +static unsigned int apple_soc_cpufreq_get_rate(unsigned int cpu) +{ + struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu); + struct apple_cpu_priv *priv = policy->driver_data; + struct cpufreq_frequency_table *p; + unsigned int pstate; + + if (priv->info->cur_pstate_mask) { + u64 reg = readq_relaxed(priv->reg_base + APPLE_DVFS_STATUS); + + pstate = (reg & priv->info->cur_pstate_mask) >> priv->info->cur_pstate_shift; + } else { + /* + * For the fallback case we might not know the layout of DVFS_STATUS, + * so just use the command register value (which ignores boost limitations). + */ + u64 reg = readq_relaxed(priv->reg_base + APPLE_DVFS_CMD); + + pstate = FIELD_GET(APPLE_DVFS_CMD_PS1, reg); + } + + cpufreq_for_each_valid_entry(p, policy->freq_table) + if (p->driver_data == pstate) + return p->frequency; + + dev_err(priv->cpu_dev, "could not find frequency for pstate %d\n", + pstate); + return 0; +} + +static int apple_soc_cpufreq_set_target(struct cpufreq_policy *policy, + unsigned int index) +{ + struct apple_cpu_priv *priv = policy->driver_data; + unsigned int pstate = policy->freq_table[index].driver_data; + u64 reg; + + /* Fallback for newer SoCs */ + if (index > priv->info->max_pstate) + index = priv->info->max_pstate; + + if (readq_poll_timeout_atomic(priv->reg_base + APPLE_DVFS_CMD, reg, + !(reg & APPLE_DVFS_CMD_BUSY), 2, + APPLE_DVFS_TRANSITION_TIMEOUT)) { + return -EIO; + } + + reg &= ~(APPLE_DVFS_CMD_PS1 | APPLE_DVFS_CMD_PS2); + reg |= FIELD_PREP(APPLE_DVFS_CMD_PS1, pstate); + reg |= FIELD_PREP(APPLE_DVFS_CMD_PS2, pstate); + reg |= APPLE_DVFS_CMD_SET; + + writeq_relaxed(reg, priv->reg_base + APPLE_DVFS_CMD); + + return 0; +} + +static unsigned int apple_soc_cpufreq_fast_switch(struct cpufreq_policy *policy, + unsigned int target_freq) +{ + if (apple_soc_cpufreq_set_target(policy, policy->cached_resolved_idx) < 0) + return 0; + + return policy->freq_table[policy->cached_resolved_idx].frequency; +} + +static int apple_soc_cpufreq_find_cluster(struct cpufreq_policy *policy, + void __iomem **reg_base, + const struct apple_soc_cpufreq_info **info) +{ + struct of_phandle_args args; + const struct of_device_id *match; + int ret = 0; + + ret = of_perf_domain_get_sharing_cpumask(policy->cpu, "performance-domains", + "#performance-domain-cells", + policy->cpus, &args); + if (ret < 0) + return ret; + + match = of_match_node(apple_soc_cpufreq_of_match, args.np); + of_node_put(args.np); + if (!match) + return -ENODEV; + + *info = match->data; + + *reg_base = of_iomap(args.np, 0); + if (IS_ERR(*reg_base)) + return PTR_ERR(*reg_base); + + return 0; +} + +static struct freq_attr *apple_soc_cpufreq_hw_attr[] = { + &cpufreq_freq_attr_scaling_available_freqs, + NULL, /* Filled in below if boost is enabled */ + NULL, +}; + +static int apple_soc_cpufreq_init(struct cpufreq_policy *policy) +{ + int ret, i; + unsigned int transition_latency; + void __iomem *reg_base; + struct device *cpu_dev; + struct apple_cpu_priv *priv; + const struct apple_soc_cpufreq_info *info; + struct cpufreq_frequency_table *freq_table; + + cpu_dev = get_cpu_device(policy->cpu); + if (!cpu_dev) { + pr_err("failed to get cpu%d device\n", policy->cpu); + return -ENODEV; + } + + ret = dev_pm_opp_of_add_table(cpu_dev); + if (ret < 0) { + dev_err(cpu_dev, "%s: failed to add OPP table: %d\n", __func__, ret); + return ret; + } + + ret = apple_soc_cpufreq_find_cluster(policy, ®_base, &info); + if (ret) { + dev_err(cpu_dev, "%s: failed to get cluster info: %d\n", __func__, ret); + return ret; + } + + ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus); + if (ret) { + dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n", __func__, ret); + goto out_iounmap; + } + + ret = dev_pm_opp_get_opp_count(cpu_dev); + if (ret <= 0) { + dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n"); + ret = -EPROBE_DEFER; + goto out_free_opp; + } + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) { + ret = -ENOMEM; + goto out_free_opp; + } + + ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table); + if (ret) { + dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret); + goto out_free_priv; + } + + /* Get OPP levels (p-state indexes) and stash them in driver_data */ + for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) { + unsigned long rate = freq_table[i].frequency * 1000 + 999; + struct dev_pm_opp *opp = dev_pm_opp_find_freq_floor(cpu_dev, &rate); + + if (IS_ERR(opp)) { + ret = PTR_ERR(opp); + goto out_free_cpufreq_table; + } + freq_table[i].driver_data = dev_pm_opp_get_level(opp); + dev_pm_opp_put(opp); + } + + priv->cpu_dev = cpu_dev; + priv->reg_base = reg_base; + priv->info = info; + policy->driver_data = priv; + policy->freq_table = freq_table; + + transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev); + if (!transition_latency) + transition_latency = CPUFREQ_ETERNAL; + + policy->cpuinfo.transition_latency = transition_latency; + policy->dvfs_possible_from_any_cpu = true; + policy->fast_switch_possible = true; + + if (policy_has_boost_freq(policy)) { + ret = cpufreq_enable_boost_support(); + if (ret) { + dev_warn(cpu_dev, "failed to enable boost: %d\n", ret); + } else { + apple_soc_cpufreq_hw_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs; + apple_soc_cpufreq_driver.boost_enabled = true; + } + } + + return 0; + +out_free_cpufreq_table: + dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); +out_free_priv: + kfree(priv); +out_free_opp: + dev_pm_opp_remove_all_dynamic(cpu_dev); +out_iounmap: + iounmap(reg_base); + return ret; +} + +static int apple_soc_cpufreq_exit(struct cpufreq_policy *policy) +{ + struct apple_cpu_priv *priv = policy->driver_data; + + dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table); + dev_pm_opp_remove_all_dynamic(priv->cpu_dev); + iounmap(priv->reg_base); + kfree(priv); + + return 0; +} + +static struct cpufreq_driver apple_soc_cpufreq_driver = { + .name = "apple-cpufreq", + .flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY | + CPUFREQ_NEED_INITIAL_FREQ_CHECK | CPUFREQ_IS_COOLING_DEV, + .verify = cpufreq_generic_frequency_table_verify, + .attr = cpufreq_generic_attr, + .get = apple_soc_cpufreq_get_rate, + .init = apple_soc_cpufreq_init, + .exit = apple_soc_cpufreq_exit, + .target_index = apple_soc_cpufreq_set_target, + .fast_switch = apple_soc_cpufreq_fast_switch, + .register_em = cpufreq_register_em_with_opp, + .attr = apple_soc_cpufreq_hw_attr, +}; + +static int __init apple_soc_cpufreq_module_init(void) +{ + if (!of_machine_is_compatible("apple,arm-platform")) + return -ENODEV; + + return cpufreq_register_driver(&apple_soc_cpufreq_driver); +} +module_init(apple_soc_cpufreq_module_init); + +static void __exit apple_soc_cpufreq_module_exit(void) +{ + cpufreq_unregister_driver(&apple_soc_cpufreq_driver); +} +module_exit(apple_soc_cpufreq_module_exit); + +MODULE_DEVICE_TABLE(of, apple_soc_cpufreq_of_match); +MODULE_AUTHOR("Hector Martin <marcan@marcan.st>"); +MODULE_DESCRIPTION("Apple SoC CPU cluster DVFS driver"); +MODULE_LICENSE("GPL"); |