diff options
Diffstat (limited to 'drivers/cpuidle/cpuidle-tegra.c')
| -rw-r--r-- | drivers/cpuidle/cpuidle-tegra.c | 392 |
1 files changed, 392 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle-tegra.c b/drivers/cpuidle/cpuidle-tegra.c new file mode 100644 index 000000000000..313b0290e97b --- /dev/null +++ b/drivers/cpuidle/cpuidle-tegra.c @@ -0,0 +1,392 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * CPU idle driver for Tegra CPUs + * + * Copyright (c) 2010-2013, NVIDIA Corporation. + * Copyright (c) 2011 Google, Inc. + * Author: Colin Cross <ccross@android.com> + * Gary King <gking@nvidia.com> + * + * Rework for 3.3 by Peter De Schrijver <pdeschrijver@nvidia.com> + * + * Tegra20/124 driver unification by Dmitry Osipenko <digetx@gmail.com> + */ + +#define pr_fmt(fmt) "tegra-cpuidle: " fmt + +#include <linux/atomic.h> +#include <linux/cpuidle.h> +#include <linux/cpumask.h> +#include <linux/cpu_pm.h> +#include <linux/delay.h> +#include <linux/errno.h> +#include <linux/platform_device.h> +#include <linux/types.h> + +#include <linux/clk/tegra.h> +#include <linux/firmware/trusted_foundations.h> + +#include <soc/tegra/cpuidle.h> +#include <soc/tegra/flowctrl.h> +#include <soc/tegra/fuse.h> +#include <soc/tegra/irq.h> +#include <soc/tegra/pm.h> +#include <soc/tegra/pmc.h> + +#include <asm/cpuidle.h> +#include <asm/firmware.h> +#include <asm/smp_plat.h> +#include <asm/suspend.h> + +enum tegra_state { + TEGRA_C1, + TEGRA_C7, + TEGRA_CC6, + TEGRA_STATE_COUNT, +}; + +static atomic_t tegra_idle_barrier; +static atomic_t tegra_abort_flag; + +static inline bool tegra_cpuidle_using_firmware(void) +{ + return firmware_ops->prepare_idle && firmware_ops->do_idle; +} + +static void tegra_cpuidle_report_cpus_state(void) +{ + unsigned long cpu, lcpu, csr; + + for_each_cpu(lcpu, cpu_possible_mask) { + cpu = cpu_logical_map(lcpu); + csr = flowctrl_read_cpu_csr(cpu); + + pr_err("cpu%lu: online=%d flowctrl_csr=0x%08lx\n", + cpu, cpu_online(lcpu), csr); + } +} + +static int tegra_cpuidle_wait_for_secondary_cpus_parking(void) +{ + unsigned int retries = 3; + + while (retries--) { + unsigned int delay_us = 10; + unsigned int timeout_us = 500 * 1000 / delay_us; + + /* + * The primary CPU0 core shall wait for the secondaries + * shutdown in order to power-off CPU's cluster safely. + * The timeout value depends on the current CPU frequency, + * it takes about 40-150us in average and over 1000us in + * a worst case scenario. + */ + do { + if (tegra_cpu_rail_off_ready()) + return 0; + + udelay(delay_us); + + } while (timeout_us--); + + pr_err("secondary CPU taking too long to park\n"); + + tegra_cpuidle_report_cpus_state(); + } + + pr_err("timed out waiting secondaries to park\n"); + + return -ETIMEDOUT; +} + +static void tegra_cpuidle_unpark_secondary_cpus(void) +{ + unsigned int cpu, lcpu; + + for_each_cpu(lcpu, cpu_online_mask) { + cpu = cpu_logical_map(lcpu); + + if (cpu > 0) { + tegra_enable_cpu_clock(cpu); + tegra_cpu_out_of_reset(cpu); + flowctrl_write_cpu_halt(cpu, 0); + } + } +} + +static int tegra_cpuidle_cc6_enter(unsigned int cpu) +{ + int ret; + + if (cpu > 0) { + ret = cpu_suspend(cpu, tegra_pm_park_secondary_cpu); + } else { + ret = tegra_cpuidle_wait_for_secondary_cpus_parking(); + if (!ret) + ret = tegra_pm_enter_lp2(); + + tegra_cpuidle_unpark_secondary_cpus(); + } + + return ret; +} + +static int tegra_cpuidle_c7_enter(void) +{ + int err; + + if (tegra_cpuidle_using_firmware()) { + err = call_firmware_op(prepare_idle, TF_PM_MODE_LP2_NOFLUSH_L2); + if (err) + return err; + + return call_firmware_op(do_idle, 0); + } + + return cpu_suspend(0, tegra30_pm_secondary_cpu_suspend); +} + +static int tegra_cpuidle_coupled_barrier(struct cpuidle_device *dev) +{ + if (tegra_pending_sgi()) { + /* + * CPU got local interrupt that will be lost after GIC's + * shutdown because GIC driver doesn't save/restore the + * pending SGI state across CPU cluster PM. Abort and retry + * next time. + */ + atomic_set(&tegra_abort_flag, 1); + } + + cpuidle_coupled_parallel_barrier(dev, &tegra_idle_barrier); + + if (atomic_read(&tegra_abort_flag)) { + cpuidle_coupled_parallel_barrier(dev, &tegra_idle_barrier); + atomic_set(&tegra_abort_flag, 0); + return -EINTR; + } + + return 0; +} + +static int tegra_cpuidle_state_enter(struct cpuidle_device *dev, + int index, unsigned int cpu) +{ + int ret; + + /* + * CC6 state is the "CPU cluster power-off" state. In order to + * enter this state, at first the secondary CPU cores need to be + * parked into offline mode, then the last CPU should clean out + * remaining dirty cache lines into DRAM and trigger Flow Controller + * logic that turns off the cluster's power domain (which includes + * CPU cores, GIC and L2 cache). + */ + if (index == TEGRA_CC6) { + ret = tegra_cpuidle_coupled_barrier(dev); + if (ret) + return ret; + } + + local_fiq_disable(); + tegra_pm_set_cpu_in_lp2(); + cpu_pm_enter(); + + switch (index) { + case TEGRA_C7: + ret = tegra_cpuidle_c7_enter(); + break; + + case TEGRA_CC6: + ret = tegra_cpuidle_cc6_enter(cpu); + break; + + default: + ret = -EINVAL; + break; + } + + cpu_pm_exit(); + tegra_pm_clear_cpu_in_lp2(); + local_fiq_enable(); + + return ret; +} + +static int tegra_cpuidle_adjust_state_index(int index, unsigned int cpu) +{ + /* + * On Tegra30 CPU0 can't be power-gated separately from secondary + * cores because it gates the whole CPU cluster. + */ + if (cpu > 0 || index != TEGRA_C7 || tegra_get_chip_id() != TEGRA30) + return index; + + /* put CPU0 into C1 if C7 is requested and secondaries are online */ + if (!IS_ENABLED(CONFIG_PM_SLEEP) || num_online_cpus() > 1) + index = TEGRA_C1; + else + index = TEGRA_CC6; + + return index; +} + +static int tegra_cpuidle_enter(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + unsigned int cpu = cpu_logical_map(dev->cpu); + int err; + + index = tegra_cpuidle_adjust_state_index(index, cpu); + if (dev->states_usage[index].disable) + return -1; + + if (index == TEGRA_C1) + err = arm_cpuidle_simple_enter(dev, drv, index); + else + err = tegra_cpuidle_state_enter(dev, index, cpu); + + if (err && (err != -EINTR || index != TEGRA_CC6)) + pr_err_once("failed to enter state %d err: %d\n", index, err); + + return err ? -1 : index; +} + +static void tegra114_enter_s2idle(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + tegra_cpuidle_enter(dev, drv, index); +} + +/* + * The previous versions of Tegra CPUIDLE driver used a different "legacy" + * terminology for naming of the idling states, while this driver uses the + * new terminology. + * + * Mapping of the old terms into the new ones: + * + * Old | New + * --------- + * LP3 | C1 (CPU core clock gating) + * LP2 | C7 (CPU core power gating) + * LP2 | CC6 (CPU cluster power gating) + * + * Note that that the older CPUIDLE driver versions didn't explicitly + * differentiate the LP2 states because these states either used the same + * code path or because CC6 wasn't supported. + */ +static struct cpuidle_driver tegra_idle_driver = { + .name = "tegra_idle", + .states = { + [TEGRA_C1] = ARM_CPUIDLE_WFI_STATE_PWR(600), + [TEGRA_C7] = { + .enter = tegra_cpuidle_enter, + .exit_latency = 2000, + .target_residency = 2200, + .power_usage = 100, + .flags = CPUIDLE_FLAG_TIMER_STOP, + .name = "C7", + .desc = "CPU core powered off", + }, + [TEGRA_CC6] = { + .enter = tegra_cpuidle_enter, + .exit_latency = 5000, + .target_residency = 10000, + .power_usage = 0, + .flags = CPUIDLE_FLAG_TIMER_STOP | + CPUIDLE_FLAG_COUPLED, + .name = "CC6", + .desc = "CPU cluster powered off", + }, + }, + .state_count = TEGRA_STATE_COUNT, + .safe_state_index = TEGRA_C1, +}; + +static inline void tegra_cpuidle_disable_state(enum tegra_state state) +{ + cpuidle_driver_state_disabled(&tegra_idle_driver, state, true); +} + +/* + * Tegra20 HW appears to have a bug such that PCIe device interrupts, whether + * they are legacy IRQs or MSI, are lost when CC6 is enabled. To work around + * this, simply disable CC6 if the PCI driver and DT node are both enabled. + */ +void tegra_cpuidle_pcie_irqs_in_use(void) +{ + struct cpuidle_state *state_cc6 = &tegra_idle_driver.states[TEGRA_CC6]; + + if ((state_cc6->flags & CPUIDLE_FLAG_UNUSABLE) || + tegra_get_chip_id() != TEGRA20) + return; + + pr_info("disabling CC6 state, since PCIe IRQs are in use\n"); + tegra_cpuidle_disable_state(TEGRA_CC6); +} + +static void tegra_cpuidle_setup_tegra114_c7_state(void) +{ + struct cpuidle_state *s = &tegra_idle_driver.states[TEGRA_C7]; + + s->enter_s2idle = tegra114_enter_s2idle; + s->target_residency = 1000; + s->exit_latency = 500; +} + +static int tegra_cpuidle_probe(struct platform_device *pdev) +{ + /* LP2 could be disabled in device-tree */ + if (tegra_pmc_get_suspend_mode() < TEGRA_SUSPEND_LP2) + tegra_cpuidle_disable_state(TEGRA_CC6); + + /* + * Required suspend-resume functionality, which is provided by the + * Tegra-arch core and PMC driver, is unavailable if PM-sleep option + * is disabled. + */ + if (!IS_ENABLED(CONFIG_PM_SLEEP)) { + if (!tegra_cpuidle_using_firmware()) + tegra_cpuidle_disable_state(TEGRA_C7); + + tegra_cpuidle_disable_state(TEGRA_CC6); + } + + /* + * Generic WFI state (also known as C1 or LP3) and the coupled CPU + * cluster power-off (CC6 or LP2) states are common for all Tegra SoCs. + */ + switch (tegra_get_chip_id()) { + case TEGRA20: + /* Tegra20 isn't capable to power-off individual CPU cores */ + tegra_cpuidle_disable_state(TEGRA_C7); + break; + + case TEGRA30: + tegra_cpuidle_disable_state(TEGRA_CC6); + break; + + case TEGRA114: + case TEGRA124: + tegra_cpuidle_setup_tegra114_c7_state(); + + /* coupled CC6 (LP2) state isn't implemented yet */ + tegra_cpuidle_disable_state(TEGRA_CC6); + break; + + default: + return -EINVAL; + } + + return cpuidle_register(&tegra_idle_driver, cpu_possible_mask); +} + +static struct platform_driver tegra_cpuidle_driver = { + .probe = tegra_cpuidle_probe, + .driver = { + .name = "tegra-cpuidle", + }, +}; +builtin_platform_driver(tegra_cpuidle_driver); |