Ishan Shah
484758e7a6
Adding a driver to handle setup and trigger for IST through the L4T kernel. This driver "hijacks" the current Hotplug entry/exit flow to instead trigger the core to enter the RIST state. Upon failure or success, the core will then be left in the "unplugged" state, to be brought back online at a later time manually. This set of changes is mainly meant for testing RIST in L4T-based systems. This is not intended for production use-cases. TPS-589 Signed-off-by: Ishan Shah <ishah@nvidia.com> Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com> Acked-by: Noah Wager <noah.wager@canonical.com> Acked-by: Jacob Martin <jacob.martin@canonical.com> Signed-off-by: Noah Wager <noah.wager@canonical.com>
133 lines
2.7 KiB
C
133 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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*
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* Copyright (C) 2013 ARM Limited
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*
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* Author: Will Deacon <will.deacon@arm.com>
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*/
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#define pr_fmt(fmt) "psci: " fmt
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#include <linux/init.h>
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#include <linux/of.h>
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#include <linux/smp.h>
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#include <linux/delay.h>
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#include <linux/psci.h>
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#include <linux/mm.h>
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#include <uapi/linux/psci.h>
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#include <asm/cpu_ops.h>
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#include <asm/errno.h>
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#include <asm/smp_plat.h>
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#ifdef CONFIG_HOTPLUG_CPU
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#include <misc/nv_ist.h>
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#endif
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static int __init cpu_psci_cpu_init(unsigned int cpu)
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{
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return 0;
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}
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static int __init cpu_psci_cpu_prepare(unsigned int cpu)
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{
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if (!psci_ops.cpu_on) {
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pr_err("no cpu_on method, not booting CPU%d\n", cpu);
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return -ENODEV;
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}
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return 0;
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}
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static int cpu_psci_cpu_boot(unsigned int cpu)
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{
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phys_addr_t pa_secondary_entry = __pa_symbol(secondary_entry);
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int err = psci_ops.cpu_on(cpu_logical_map(cpu), pa_secondary_entry);
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if (err)
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pr_err("failed to boot CPU%d (%d)\n", cpu, err);
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return err;
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}
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#ifdef CONFIG_HOTPLUG_CPU
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static bool cpu_psci_cpu_can_disable(unsigned int cpu)
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{
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return !psci_tos_resident_on(cpu);
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}
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static int cpu_psci_cpu_disable(unsigned int cpu)
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{
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/* Fail early if we don't have CPU_OFF support */
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if (!psci_ops.cpu_off)
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return -EOPNOTSUPP;
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/* Trusted OS will deny CPU_OFF */
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if (psci_tos_resident_on(cpu))
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return -EPERM;
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return 0;
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}
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static void cpu_psci_cpu_die(unsigned int cpu)
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{
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if (is_ist_enabled(cpu)) {
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cpu_enter_ist(cpu);
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} else {
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/*
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* There are no known implementations of PSCI actually using the
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* power state field, pass a sensible default for now.
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*/
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u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
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PSCI_0_2_POWER_STATE_TYPE_SHIFT;
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psci_ops.cpu_off(state);
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}
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}
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static int cpu_psci_cpu_kill(unsigned int cpu)
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{
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int err;
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unsigned long start, end;
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if (!psci_ops.affinity_info)
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return 0;
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/*
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* cpu_kill could race with cpu_die and we can
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* potentially end up declaring this cpu undead
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* while it is dying. So, try again a few times.
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*/
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start = jiffies;
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end = start + msecs_to_jiffies(100);
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do {
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err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
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if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
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pr_info("CPU%d killed (polled %d ms)\n", cpu,
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jiffies_to_msecs(jiffies - start));
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return 0;
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}
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usleep_range(100, 1000);
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} while (time_before(jiffies, end));
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pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
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cpu, err);
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return -ETIMEDOUT;
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}
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#endif
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const struct cpu_operations cpu_psci_ops = {
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.name = "psci",
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.cpu_init = cpu_psci_cpu_init,
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.cpu_prepare = cpu_psci_cpu_prepare,
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.cpu_boot = cpu_psci_cpu_boot,
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#ifdef CONFIG_HOTPLUG_CPU
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.cpu_can_disable = cpu_psci_cpu_can_disable,
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.cpu_disable = cpu_psci_cpu_disable,
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.cpu_die = cpu_psci_cpu_die,
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.cpu_kill = cpu_psci_cpu_kill,
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#endif
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};
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