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author | 2020-02-25 01:40:52 +0300 | |
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committer | 2020-03-13 11:31:58 +0100 | |
commit | 860fbde438dc88d2fedf75965963b96c9041a0d5 (patch) | |
tree | e8ac73717e72a48c91ff7116686bb5698b8f527f /drivers/cpuidle/cpuidle-tegra.c | |
parent | Merge branch 'for-5.7/arm/core' into for-5.7/cpuidle (diff) | |
download | linux-860fbde438dc88d2fedf75965963b96c9041a0d5.tar.gz linux-860fbde438dc88d2fedf75965963b96c9041a0d5.tar.bz2 linux-860fbde438dc88d2fedf75965963b96c9041a0d5.zip |
cpuidle: Refactor and move out NVIDIA Tegra20 driver into drivers/cpuidle
The driver's code is refactored in a way that will make it easy to
support Tegra30/114/124 SoCs by this unified driver later on. The
current functionality is equal to the old Tegra20 driver, only the
code's structure changed a tad. This is also a proper platform driver
now.
Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Diffstat (limited to 'drivers/cpuidle/cpuidle-tegra.c')
-rw-r--r-- | drivers/cpuidle/cpuidle-tegra.c | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle-tegra.c b/drivers/cpuidle/cpuidle-tegra.c new file mode 100644 index 000000000000..5691bdcf11cb --- /dev/null +++ b/drivers/cpuidle/cpuidle-tegra.c @@ -0,0 +1,280 @@ +// 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 <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 <asm/cpuidle.h> +#include <asm/smp_plat.h> +#include <asm/suspend.h> + +enum tegra_state { + TEGRA_C1, + TEGRA_CC6, + TEGRA_STATE_COUNT, +}; + +static atomic_t tegra_idle_barrier; +static atomic_t tegra_abort_flag; + +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_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_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_enter(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + unsigned int cpu = cpu_logical_map(dev->cpu); + int err; + + err = tegra_cpuidle_state_enter(dev, index, cpu); + if (err && err != -EINTR) + pr_err_once("cpu%u failed to enter idle state %d err: %d\n", + cpu, index, err); + + return err ? -1 : 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_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 int tegra_cpuidle_probe(struct platform_device *pdev) +{ + /* + * 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)) + tegra_cpuidle_disable_state(TEGRA_CC6); + + 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); |