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cpuidle: Add RISC-V SBI CPU idle driver
The RISC-V SBI HSM extension provides HSM suspend call which can be used by Linux RISC-V to enter platform specific low-power state. This patch adds a CPU idle driver based on RISC-V SBI calls which will populate idle states from device tree and use SBI calls to entry these idle states. Signed-off-by: Anup Patel <anup.patel@wdc.com> Signed-off-by: Anup Patel <apatel@ventanamicro.com> Acked-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Anup Patel
Palmer Dabbelt
parent
9d976d6721
commit
6abf32f1d9
@ -5058,6 +5058,13 @@ S: Supported
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F: drivers/cpuidle/dt_idle_genpd.c
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F: drivers/cpuidle/dt_idle_genpd.h
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CPUIDLE DRIVER - RISC-V SBI
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M: Anup Patel <anup@brainfault.org>
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L: linux-pm@vger.kernel.org
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L: linux-riscv@lists.infradead.org
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S: Maintained
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F: drivers/cpuidle/cpuidle-riscv-sbi.c
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CRAMFS FILESYSTEM
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M: Nicolas Pitre <nico@fluxnic.net>
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S: Maintained
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@ -66,6 +66,11 @@ depends on PPC
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source "drivers/cpuidle/Kconfig.powerpc"
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endmenu
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menu "RISC-V CPU Idle Drivers"
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depends on RISCV
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source "drivers/cpuidle/Kconfig.riscv"
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endmenu
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config HALTPOLL_CPUIDLE
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tristate "Halt poll cpuidle driver"
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depends on X86 && KVM_GUEST
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15
drivers/cpuidle/Kconfig.riscv
Normal file
15
drivers/cpuidle/Kconfig.riscv
Normal file
@ -0,0 +1,15 @@
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# SPDX-License-Identifier: GPL-2.0-only
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#
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# RISC-V CPU Idle drivers
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#
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config RISCV_SBI_CPUIDLE
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bool "RISC-V SBI CPU idle Driver"
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depends on RISCV_SBI
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select DT_IDLE_STATES
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select CPU_IDLE_MULTIPLE_DRIVERS
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select DT_IDLE_GENPD if PM_GENERIC_DOMAINS_OF
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help
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Select this option to enable RISC-V SBI firmware based CPU idle
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driver for RISC-V systems. This drivers also supports hierarchical
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DT based layout of the idle state.
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@ -35,3 +35,7 @@ obj-$(CONFIG_MIPS_CPS_CPUIDLE) += cpuidle-cps.o
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# POWERPC drivers
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obj-$(CONFIG_PSERIES_CPUIDLE) += cpuidle-pseries.o
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obj-$(CONFIG_POWERNV_CPUIDLE) += cpuidle-powernv.o
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###############################################################################
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# RISC-V drivers
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obj-$(CONFIG_RISCV_SBI_CPUIDLE) += cpuidle-riscv-sbi.o
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627
drivers/cpuidle/cpuidle-riscv-sbi.c
Normal file
627
drivers/cpuidle/cpuidle-riscv-sbi.c
Normal file
@ -0,0 +1,627 @@
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* RISC-V SBI CPU idle driver.
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*
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* Copyright (c) 2021 Western Digital Corporation or its affiliates.
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* Copyright (c) 2022 Ventana Micro Systems Inc.
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*/
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#define pr_fmt(fmt) "cpuidle-riscv-sbi: " fmt
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#include <linux/cpuidle.h>
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#include <linux/cpumask.h>
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#include <linux/cpu_pm.h>
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#include <linux/cpu_cooling.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/slab.h>
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#include <linux/platform_device.h>
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#include <linux/pm_domain.h>
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#include <linux/pm_runtime.h>
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#include <asm/cpuidle.h>
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#include <asm/sbi.h>
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#include <asm/suspend.h>
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#include "dt_idle_states.h"
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#include "dt_idle_genpd.h"
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struct sbi_cpuidle_data {
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u32 *states;
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struct device *dev;
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};
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struct sbi_domain_state {
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bool available;
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u32 state;
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};
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static DEFINE_PER_CPU_READ_MOSTLY(struct sbi_cpuidle_data, sbi_cpuidle_data);
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static DEFINE_PER_CPU(struct sbi_domain_state, domain_state);
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static bool sbi_cpuidle_use_osi;
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static bool sbi_cpuidle_use_cpuhp;
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static bool sbi_cpuidle_pd_allow_domain_state;
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static inline void sbi_set_domain_state(u32 state)
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{
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struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
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data->available = true;
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data->state = state;
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}
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static inline u32 sbi_get_domain_state(void)
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{
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struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
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return data->state;
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}
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static inline void sbi_clear_domain_state(void)
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{
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struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
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data->available = false;
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}
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static inline bool sbi_is_domain_state_available(void)
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{
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struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
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return data->available;
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}
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static int sbi_suspend_finisher(unsigned long suspend_type,
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unsigned long resume_addr,
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unsigned long opaque)
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{
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struct sbiret ret;
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ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_SUSPEND,
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suspend_type, resume_addr, opaque, 0, 0, 0);
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return (ret.error) ? sbi_err_map_linux_errno(ret.error) : 0;
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}
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static int sbi_suspend(u32 state)
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{
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if (state & SBI_HSM_SUSP_NON_RET_BIT)
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return cpu_suspend(state, sbi_suspend_finisher);
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else
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return sbi_suspend_finisher(state, 0, 0);
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}
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static int sbi_cpuidle_enter_state(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int idx)
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{
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u32 *states = __this_cpu_read(sbi_cpuidle_data.states);
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return CPU_PM_CPU_IDLE_ENTER_PARAM(sbi_suspend, idx, states[idx]);
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}
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static int __sbi_enter_domain_idle_state(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int idx,
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bool s2idle)
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{
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struct sbi_cpuidle_data *data = this_cpu_ptr(&sbi_cpuidle_data);
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u32 *states = data->states;
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struct device *pd_dev = data->dev;
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u32 state;
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int ret;
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ret = cpu_pm_enter();
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if (ret)
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return -1;
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/* Do runtime PM to manage a hierarchical CPU toplogy. */
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rcu_irq_enter_irqson();
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if (s2idle)
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dev_pm_genpd_suspend(pd_dev);
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else
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pm_runtime_put_sync_suspend(pd_dev);
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rcu_irq_exit_irqson();
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if (sbi_is_domain_state_available())
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state = sbi_get_domain_state();
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else
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state = states[idx];
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ret = sbi_suspend(state) ? -1 : idx;
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rcu_irq_enter_irqson();
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if (s2idle)
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dev_pm_genpd_resume(pd_dev);
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else
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pm_runtime_get_sync(pd_dev);
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rcu_irq_exit_irqson();
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cpu_pm_exit();
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/* Clear the domain state to start fresh when back from idle. */
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sbi_clear_domain_state();
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return ret;
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}
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static int sbi_enter_domain_idle_state(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int idx)
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{
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return __sbi_enter_domain_idle_state(dev, drv, idx, false);
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}
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static int sbi_enter_s2idle_domain_idle_state(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int idx)
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{
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return __sbi_enter_domain_idle_state(dev, drv, idx, true);
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}
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static int sbi_cpuidle_cpuhp_up(unsigned int cpu)
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{
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struct device *pd_dev = __this_cpu_read(sbi_cpuidle_data.dev);
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if (pd_dev)
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pm_runtime_get_sync(pd_dev);
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return 0;
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}
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static int sbi_cpuidle_cpuhp_down(unsigned int cpu)
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{
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struct device *pd_dev = __this_cpu_read(sbi_cpuidle_data.dev);
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if (pd_dev) {
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pm_runtime_put_sync(pd_dev);
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/* Clear domain state to start fresh at next online. */
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sbi_clear_domain_state();
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}
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return 0;
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}
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static void sbi_idle_init_cpuhp(void)
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{
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int err;
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if (!sbi_cpuidle_use_cpuhp)
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return;
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err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING,
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"cpuidle/sbi:online",
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sbi_cpuidle_cpuhp_up,
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sbi_cpuidle_cpuhp_down);
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if (err)
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pr_warn("Failed %d while setup cpuhp state\n", err);
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}
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static const struct of_device_id sbi_cpuidle_state_match[] = {
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{ .compatible = "riscv,idle-state",
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.data = sbi_cpuidle_enter_state },
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{ },
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};
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static bool sbi_suspend_state_is_valid(u32 state)
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{
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if (state > SBI_HSM_SUSPEND_RET_DEFAULT &&
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state < SBI_HSM_SUSPEND_RET_PLATFORM)
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return false;
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if (state > SBI_HSM_SUSPEND_NON_RET_DEFAULT &&
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state < SBI_HSM_SUSPEND_NON_RET_PLATFORM)
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return false;
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return true;
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}
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static int sbi_dt_parse_state_node(struct device_node *np, u32 *state)
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{
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int err = of_property_read_u32(np, "riscv,sbi-suspend-param", state);
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if (err) {
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pr_warn("%pOF missing riscv,sbi-suspend-param property\n", np);
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return err;
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}
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if (!sbi_suspend_state_is_valid(*state)) {
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pr_warn("Invalid SBI suspend state %#x\n", *state);
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return -EINVAL;
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}
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return 0;
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}
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static int sbi_dt_cpu_init_topology(struct cpuidle_driver *drv,
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struct sbi_cpuidle_data *data,
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unsigned int state_count, int cpu)
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{
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/* Currently limit the hierarchical topology to be used in OSI mode. */
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if (!sbi_cpuidle_use_osi)
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return 0;
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data->dev = dt_idle_attach_cpu(cpu, "sbi");
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if (IS_ERR_OR_NULL(data->dev))
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return PTR_ERR_OR_ZERO(data->dev);
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/*
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* Using the deepest state for the CPU to trigger a potential selection
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* of a shared state for the domain, assumes the domain states are all
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* deeper states.
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*/
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drv->states[state_count - 1].enter = sbi_enter_domain_idle_state;
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drv->states[state_count - 1].enter_s2idle =
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sbi_enter_s2idle_domain_idle_state;
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sbi_cpuidle_use_cpuhp = true;
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return 0;
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}
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static int sbi_cpuidle_dt_init_states(struct device *dev,
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struct cpuidle_driver *drv,
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unsigned int cpu,
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unsigned int state_count)
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{
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struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
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struct device_node *state_node;
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struct device_node *cpu_node;
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u32 *states;
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int i, ret;
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cpu_node = of_cpu_device_node_get(cpu);
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if (!cpu_node)
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return -ENODEV;
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states = devm_kcalloc(dev, state_count, sizeof(*states), GFP_KERNEL);
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if (!states) {
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ret = -ENOMEM;
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goto fail;
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}
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/* Parse SBI specific details from state DT nodes */
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for (i = 1; i < state_count; i++) {
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state_node = of_get_cpu_state_node(cpu_node, i - 1);
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if (!state_node)
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break;
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ret = sbi_dt_parse_state_node(state_node, &states[i]);
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of_node_put(state_node);
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if (ret)
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return ret;
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pr_debug("sbi-state %#x index %d\n", states[i], i);
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}
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if (i != state_count) {
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ret = -ENODEV;
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goto fail;
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}
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/* Initialize optional data, used for the hierarchical topology. */
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ret = sbi_dt_cpu_init_topology(drv, data, state_count, cpu);
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if (ret < 0)
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return ret;
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/* Store states in the per-cpu struct. */
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data->states = states;
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fail:
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of_node_put(cpu_node);
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return ret;
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}
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static void sbi_cpuidle_deinit_cpu(int cpu)
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{
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struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
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dt_idle_detach_cpu(data->dev);
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sbi_cpuidle_use_cpuhp = false;
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}
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static int sbi_cpuidle_init_cpu(struct device *dev, int cpu)
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{
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struct cpuidle_driver *drv;
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unsigned int state_count = 0;
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int ret = 0;
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drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
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if (!drv)
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return -ENOMEM;
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drv->name = "sbi_cpuidle";
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drv->owner = THIS_MODULE;
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drv->cpumask = (struct cpumask *)cpumask_of(cpu);
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/* RISC-V architectural WFI to be represented as state index 0. */
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drv->states[0].enter = sbi_cpuidle_enter_state;
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drv->states[0].exit_latency = 1;
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drv->states[0].target_residency = 1;
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drv->states[0].power_usage = UINT_MAX;
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strcpy(drv->states[0].name, "WFI");
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strcpy(drv->states[0].desc, "RISC-V WFI");
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/*
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* If no DT idle states are detected (ret == 0) let the driver
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* initialization fail accordingly since there is no reason to
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* initialize the idle driver if only wfi is supported, the
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* default archictectural back-end already executes wfi
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* on idle entry.
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*/
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ret = dt_init_idle_driver(drv, sbi_cpuidle_state_match, 1);
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if (ret <= 0) {
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pr_debug("HART%ld: failed to parse DT idle states\n",
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cpuid_to_hartid_map(cpu));
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return ret ? : -ENODEV;
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}
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state_count = ret + 1; /* Include WFI state as well */
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/* Initialize idle states from DT. */
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ret = sbi_cpuidle_dt_init_states(dev, drv, cpu, state_count);
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if (ret) {
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pr_err("HART%ld: failed to init idle states\n",
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cpuid_to_hartid_map(cpu));
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return ret;
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}
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ret = cpuidle_register(drv, NULL);
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if (ret)
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goto deinit;
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cpuidle_cooling_register(drv);
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return 0;
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deinit:
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sbi_cpuidle_deinit_cpu(cpu);
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return ret;
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}
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static void sbi_cpuidle_domain_sync_state(struct device *dev)
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{
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/*
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* All devices have now been attached/probed to the PM domain
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* topology, hence it's fine to allow domain states to be picked.
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*/
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sbi_cpuidle_pd_allow_domain_state = true;
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}
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#ifdef CONFIG_DT_IDLE_GENPD
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static int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd)
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{
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struct genpd_power_state *state = &pd->states[pd->state_idx];
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u32 *pd_state;
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if (!state->data)
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return 0;
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if (!sbi_cpuidle_pd_allow_domain_state)
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return -EBUSY;
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/* OSI mode is enabled, set the corresponding domain state. */
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pd_state = state->data;
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sbi_set_domain_state(*pd_state);
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return 0;
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}
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|
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struct sbi_pd_provider {
|
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struct list_head link;
|
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struct device_node *node;
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};
|
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static LIST_HEAD(sbi_pd_providers);
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||||
static int sbi_pd_init(struct device_node *np)
|
||||
{
|
||||
struct generic_pm_domain *pd;
|
||||
struct sbi_pd_provider *pd_provider;
|
||||
struct dev_power_governor *pd_gov;
|
||||
int ret = -ENOMEM, state_count = 0;
|
||||
|
||||
pd = dt_idle_pd_alloc(np, sbi_dt_parse_state_node);
|
||||
if (!pd)
|
||||
goto out;
|
||||
|
||||
pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
|
||||
if (!pd_provider)
|
||||
goto free_pd;
|
||||
|
||||
pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
|
||||
|
||||
/* Allow power off when OSI is available. */
|
||||
if (sbi_cpuidle_use_osi)
|
||||
pd->power_off = sbi_cpuidle_pd_power_off;
|
||||
else
|
||||
pd->flags |= GENPD_FLAG_ALWAYS_ON;
|
||||
|
||||
/* Use governor for CPU PM domains if it has some states to manage. */
|
||||
pd_gov = state_count > 0 ? &pm_domain_cpu_gov : NULL;
|
||||
|
||||
ret = pm_genpd_init(pd, pd_gov, false);
|
||||
if (ret)
|
||||
goto free_pd_prov;
|
||||
|
||||
ret = of_genpd_add_provider_simple(np, pd);
|
||||
if (ret)
|
||||
goto remove_pd;
|
||||
|
||||
pd_provider->node = of_node_get(np);
|
||||
list_add(&pd_provider->link, &sbi_pd_providers);
|
||||
|
||||
pr_debug("init PM domain %s\n", pd->name);
|
||||
return 0;
|
||||
|
||||
remove_pd:
|
||||
pm_genpd_remove(pd);
|
||||
free_pd_prov:
|
||||
kfree(pd_provider);
|
||||
free_pd:
|
||||
dt_idle_pd_free(pd);
|
||||
out:
|
||||
pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
|
||||
return ret;
|
||||
}
|
||||
|
||||
static void sbi_pd_remove(void)
|
||||
{
|
||||
struct sbi_pd_provider *pd_provider, *it;
|
||||
struct generic_pm_domain *genpd;
|
||||
|
||||
list_for_each_entry_safe(pd_provider, it, &sbi_pd_providers, link) {
|
||||
of_genpd_del_provider(pd_provider->node);
|
||||
|
||||
genpd = of_genpd_remove_last(pd_provider->node);
|
||||
if (!IS_ERR(genpd))
|
||||
kfree(genpd);
|
||||
|
||||
of_node_put(pd_provider->node);
|
||||
list_del(&pd_provider->link);
|
||||
kfree(pd_provider);
|
||||
}
|
||||
}
|
||||
|
||||
static int sbi_genpd_probe(struct device_node *np)
|
||||
{
|
||||
struct device_node *node;
|
||||
int ret = 0, pd_count = 0;
|
||||
|
||||
if (!np)
|
||||
return -ENODEV;
|
||||
|
||||
/*
|
||||
* Parse child nodes for the "#power-domain-cells" property and
|
||||
* initialize a genpd/genpd-of-provider pair when it's found.
|
||||
*/
|
||||
for_each_child_of_node(np, node) {
|
||||
if (!of_find_property(node, "#power-domain-cells", NULL))
|
||||
continue;
|
||||
|
||||
ret = sbi_pd_init(node);
|
||||
if (ret)
|
||||
goto put_node;
|
||||
|
||||
pd_count++;
|
||||
}
|
||||
|
||||
/* Bail out if not using the hierarchical CPU topology. */
|
||||
if (!pd_count)
|
||||
goto no_pd;
|
||||
|
||||
/* Link genpd masters/subdomains to model the CPU topology. */
|
||||
ret = dt_idle_pd_init_topology(np);
|
||||
if (ret)
|
||||
goto remove_pd;
|
||||
|
||||
return 0;
|
||||
|
||||
put_node:
|
||||
of_node_put(node);
|
||||
remove_pd:
|
||||
sbi_pd_remove();
|
||||
pr_err("failed to create CPU PM domains ret=%d\n", ret);
|
||||
no_pd:
|
||||
return ret;
|
||||
}
|
||||
|
||||
#else
|
||||
|
||||
static inline int sbi_genpd_probe(struct device_node *np)
|
||||
{
|
||||
return 0;
|
||||
}
|
||||
|
||||
#endif
|
||||
|
||||
static int sbi_cpuidle_probe(struct platform_device *pdev)
|
||||
{
|
||||
int cpu, ret;
|
||||
struct cpuidle_driver *drv;
|
||||
struct cpuidle_device *dev;
|
||||
struct device_node *np, *pds_node;
|
||||
|
||||
/* Detect OSI support based on CPU DT nodes */
|
||||
sbi_cpuidle_use_osi = true;
|
||||
for_each_possible_cpu(cpu) {
|
||||
np = of_cpu_device_node_get(cpu);
|
||||
if (np &&
|
||||
of_find_property(np, "power-domains", NULL) &&
|
||||
of_find_property(np, "power-domain-names", NULL)) {
|
||||
continue;
|
||||
} else {
|
||||
sbi_cpuidle_use_osi = false;
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
/* Populate generic power domains from DT nodes */
|
||||
pds_node = of_find_node_by_path("/cpus/power-domains");
|
||||
if (pds_node) {
|
||||
ret = sbi_genpd_probe(pds_node);
|
||||
of_node_put(pds_node);
|
||||
if (ret)
|
||||
return ret;
|
||||
}
|
||||
|
||||
/* Initialize CPU idle driver for each CPU */
|
||||
for_each_possible_cpu(cpu) {
|
||||
ret = sbi_cpuidle_init_cpu(&pdev->dev, cpu);
|
||||
if (ret) {
|
||||
pr_debug("HART%ld: idle driver init failed\n",
|
||||
cpuid_to_hartid_map(cpu));
|
||||
goto out_fail;
|
||||
}
|
||||
}
|
||||
|
||||
/* Setup CPU hotplut notifiers */
|
||||
sbi_idle_init_cpuhp();
|
||||
|
||||
pr_info("idle driver registered for all CPUs\n");
|
||||
|
||||
return 0;
|
||||
|
||||
out_fail:
|
||||
while (--cpu >= 0) {
|
||||
dev = per_cpu(cpuidle_devices, cpu);
|
||||
drv = cpuidle_get_cpu_driver(dev);
|
||||
cpuidle_unregister(drv);
|
||||
sbi_cpuidle_deinit_cpu(cpu);
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static struct platform_driver sbi_cpuidle_driver = {
|
||||
.probe = sbi_cpuidle_probe,
|
||||
.driver = {
|
||||
.name = "sbi-cpuidle",
|
||||
.sync_state = sbi_cpuidle_domain_sync_state,
|
||||
},
|
||||
};
|
||||
|
||||
static int __init sbi_cpuidle_init(void)
|
||||
{
|
||||
int ret;
|
||||
struct platform_device *pdev;
|
||||
|
||||
/*
|
||||
* The SBI HSM suspend function is only available when:
|
||||
* 1) SBI version is 0.3 or higher
|
||||
* 2) SBI HSM extension is available
|
||||
*/
|
||||
if ((sbi_spec_version < sbi_mk_version(0, 3)) ||
|
||||
sbi_probe_extension(SBI_EXT_HSM) <= 0) {
|
||||
pr_info("HSM suspend not available\n");
|
||||
return 0;
|
||||
}
|
||||
|
||||
ret = platform_driver_register(&sbi_cpuidle_driver);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
pdev = platform_device_register_simple("sbi-cpuidle",
|
||||
-1, NULL, 0);
|
||||
if (IS_ERR(pdev)) {
|
||||
platform_driver_unregister(&sbi_cpuidle_driver);
|
||||
return PTR_ERR(pdev);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
device_initcall(sbi_cpuidle_init);
|
||||
Loading…
Reference in New Issue
Block a user