--- /dev/null
+// 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");
projects / users / jedix / linux-maple.git / commitdiff