arch/mips/kernel/smp-cps.c - kernel/msm-4.19 - Gitiles

 /*
  * Copyright (C) 2013 Imagination Technologies
  * Author: Paul Burton <paul.burton@imgtec.com>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
  * Free Software Foundation;  either version 2 of the  License, or (at your
  * option) any later version.
  */

 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/irqchip/mips-gic.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/smp.h>
 #include <linux/types.h>

 #include <asm/bcache.h>
 #include <asm/mips-cm.h>
 #include <asm/mips-cpc.h>
 #include <asm/mips_mt.h>
 #include <asm/mipsregs.h>
 #include <asm/pm-cps.h>
 #include <asm/r4kcache.h>
 #include <asm/smp-cps.h>
 #include <asm/time.h>
 #include <asm/uasm.h>

 static DECLARE_BITMAP(core_power, NR_CPUS);

 struct core_boot_config *mips_cps_core_bootcfg;

 static unsigned core_vpe_count(unsigned core)
 {
 	unsigned cfg;

 	if (!config_enabled(CONFIG_MIPS_MT_SMP) || !cpu_has_mipsmt)
 		return 1;

 	mips_cm_lock_other(core, 0);
 	cfg = read_gcr_co_config() & CM_GCR_Cx_CONFIG_PVPE_MSK;
 	mips_cm_unlock_other();
 	return (cfg >> CM_GCR_Cx_CONFIG_PVPE_SHF) + 1;
 }

 static void __init cps_smp_setup(void)
 {
 	unsigned int ncores, nvpes, core_vpes;
 	int c, v;

 	/* Detect & record VPE topology */
 	ncores = mips_cm_numcores();
 	pr_info("VPE topology ");
 	for (c = nvpes = 0; c < ncores; c++) {
 		core_vpes = core_vpe_count(c);
 		pr_cont("%c%u", c ? ',' : '{', core_vpes);

 		/* Use the number of VPEs in core 0 for smp_num_siblings */
 		if (!c)
 			smp_num_siblings = core_vpes;

 		for (v = 0; v < min_t(int, core_vpes, NR_CPUS - nvpes); v++) {
 			cpu_data[nvpes + v].core = c;
 #ifdef CONFIG_MIPS_MT_SMP
 			cpu_data[nvpes + v].vpe_id = v;
 #endif
 		}

 		nvpes += core_vpes;
 	}
 	pr_cont("} total %u\n", nvpes);

 	/* Indicate present CPUs (CPU being synonymous with VPE) */
 	for (v = 0; v < min_t(unsigned, nvpes, NR_CPUS); v++) {
 		set_cpu_possible(v, true);
 		set_cpu_present(v, true);
 		__cpu_number_map[v] = v;
 		__cpu_logical_map[v] = v;
 	}

 	/* Set a coherent default CCA (CWB) */
 	change_c0_config(CONF_CM_CMASK, 0x5);

 	/* Core 0 is powered up (we're running on it) */
 	bitmap_set(core_power, 0, 1);

 	/* Initialise core 0 */
 	mips_cps_core_init();

 	/* Make core 0 coherent with everything */
 	write_gcr_cl_coherence(0xff);

 #ifdef CONFIG_MIPS_MT_FPAFF
 	/* If we have an FPU, enroll ourselves in the FPU-full mask */
 	if (cpu_has_fpu)
 		cpumask_set_cpu(0, &mt_fpu_cpumask);
 #endif /* CONFIG_MIPS_MT_FPAFF */
 }

 static void __init cps_prepare_cpus(unsigned int max_cpus)
 {
 	unsigned ncores, core_vpes, c, cca;
 	bool cca_unsuitable;
 	u32 *entry_code;

 	mips_mt_set_cpuoptions();

 	/* Detect whether the CCA is unsuited to multi-core SMP */
 	cca = read_c0_config() & CONF_CM_CMASK;
 	switch (cca) {
 	case 0x4: /* CWBE */
 	case 0x5: /* CWB */
 		/* The CCA is coherent, multi-core is fine */
 		cca_unsuitable = false;
 		break;

 	default:
 		/* CCA is not coherent, multi-core is not usable */
 		cca_unsuitable = true;
 	}

 	/* Warn the user if the CCA prevents multi-core */
 	ncores = mips_cm_numcores();
 	if (cca_unsuitable && ncores > 1) {
 		pr_warn("Using only one core due to unsuitable CCA 0x%x\n",
 			cca);

 		for_each_present_cpu(c) {
 			if (cpu_data[c].core)
 				set_cpu_present(c, false);
 		}
 	}

 	/*
 	 * Patch the start of mips_cps_core_entry to provide:
 	 *
 	 * s0 = kseg0 CCA
 	 */
 	entry_code = (u32 *)&mips_cps_core_entry;
 	uasm_i_addiu(&entry_code, 16, 0, cca);
 	blast_dcache_range((unsigned long)&mips_cps_core_entry,
 			   (unsigned long)entry_code);
 	bc_wback_inv((unsigned long)&mips_cps_core_entry,
 		     (void *)entry_code - (void *)&mips_cps_core_entry);
 	__sync();

 	/* Allocate core boot configuration structs */
 	mips_cps_core_bootcfg = kcalloc(ncores, sizeof(*mips_cps_core_bootcfg),
 					GFP_KERNEL);
 	if (!mips_cps_core_bootcfg) {
 		pr_err("Failed to allocate boot config for %u cores\n", ncores);
 		goto err_out;
 	}

 	/* Allocate VPE boot configuration structs */
 	for (c = 0; c < ncores; c++) {
 		core_vpes = core_vpe_count(c);
 		mips_cps_core_bootcfg[c].vpe_config = kcalloc(core_vpes,
 				sizeof(*mips_cps_core_bootcfg[c].vpe_config),
 				GFP_KERNEL);
 		if (!mips_cps_core_bootcfg[c].vpe_config) {
 			pr_err("Failed to allocate %u VPE boot configs\n",
 			       core_vpes);
 			goto err_out;
 		}
 	}

 	/* Mark this CPU as booted */
 	atomic_set(&mips_cps_core_bootcfg[current_cpu_data.core].vpe_mask,
 		   1 << cpu_vpe_id(&current_cpu_data));

 	return;
 err_out:
 	/* Clean up allocations */
 	if (mips_cps_core_bootcfg) {
 		for (c = 0; c < ncores; c++)
 			kfree(mips_cps_core_bootcfg[c].vpe_config);
 		kfree(mips_cps_core_bootcfg);
 		mips_cps_core_bootcfg = NULL;
 	}

 	/* Effectively disable SMP by declaring CPUs not present */
 	for_each_possible_cpu(c) {
 		if (c == 0)
 			continue;
 		set_cpu_present(c, false);
 	}
 }

 static void boot_core(unsigned core)
 {
 	u32 access, stat, seq_state;
 	unsigned timeout;

 	/* Select the appropriate core */
 	mips_cm_lock_other(core, 0);

 	/* Set its reset vector */
 	write_gcr_co_reset_base(CKSEG1ADDR((unsigned long)mips_cps_core_entry));

 	/* Ensure its coherency is disabled */
 	write_gcr_co_coherence(0);

 	/* Start it with the legacy memory map and exception base */
 	write_gcr_co_reset_ext_base(CM_GCR_RESET_EXT_BASE_UEB);

 	/* Ensure the core can access the GCRs */
 	access = read_gcr_access();
 	access |= 1 << (CM_GCR_ACCESS_ACCESSEN_SHF + core);
 	write_gcr_access(access);

 	if (mips_cpc_present()) {
 		/* Reset the core */
 		mips_cpc_lock_other(core);
 		write_cpc_co_cmd(CPC_Cx_CMD_RESET);

 		timeout = 100;
 		while (true) {
 			stat = read_cpc_co_stat_conf();
 			seq_state = stat & CPC_Cx_STAT_CONF_SEQSTATE_MSK;

 			/* U6 == coherent execution, ie. the core is up */
 			if (seq_state == CPC_Cx_STAT_CONF_SEQSTATE_U6)
 				break;

 			/* Delay a little while before we start warning */
 			if (timeout) {
 				timeout--;
 				mdelay(10);
 				continue;
 			}

 			pr_warn("Waiting for core %u to start... STAT_CONF=0x%x\n",
 				core, stat);
 			mdelay(1000);
 		}

 		mips_cpc_unlock_other();
 	} else {
 		/* Take the core out of reset */
 		write_gcr_co_reset_release(0);
 	}

 	mips_cm_unlock_other();

 	/* The core is now powered up */
 	bitmap_set(core_power, core, 1);
 }

 static void remote_vpe_boot(void *dummy)
 {
 	mips_cps_boot_vpes();
 }

 static void cps_boot_secondary(int cpu, struct task_struct *idle)
 {
 	unsigned core = cpu_data[cpu].core;
 	unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]);
 	struct core_boot_config *core_cfg = &mips_cps_core_bootcfg[core];
 	struct vpe_boot_config *vpe_cfg = &core_cfg->vpe_config[vpe_id];
 	unsigned int remote;
 	int err;

 	vpe_cfg->pc = (unsigned long)&smp_bootstrap;
 	vpe_cfg->sp = __KSTK_TOS(idle);
 	vpe_cfg->gp = (unsigned long)task_thread_info(idle);

 	atomic_or(1 << cpu_vpe_id(&cpu_data[cpu]), &core_cfg->vpe_mask);

 	preempt_disable();

 	if (!test_bit(core, core_power)) {
 		/* Boot a VPE on a powered down core */
 		boot_core(core);
 		goto out;
 	}

 	if (core != current_cpu_data.core) {
 		/* Boot a VPE on another powered up core */
 		for (remote = 0; remote < NR_CPUS; remote++) {
 			if (cpu_data[remote].core != core)
 				continue;
 			if (cpu_online(remote))
 				break;
 		}
 		BUG_ON(remote >= NR_CPUS);

 		err = smp_call_function_single(remote, remote_vpe_boot,
 					       NULL, 1);
 		if (err)
 			panic("Failed to call remote CPU\n");
 		goto out;
 	}

 	BUG_ON(!cpu_has_mipsmt);

 	/* Boot a VPE on this core */
 	mips_cps_boot_vpes();
 out:
 	preempt_enable();
 }

 static void cps_init_secondary(void)
 {
 	/* Disable MT - we only want to run 1 TC per VPE */
 	if (cpu_has_mipsmt)
 		dmt();

 	change_c0_status(ST0_IM, STATUSF_IP2 | STATUSF_IP3 | STATUSF_IP4 |
 				 STATUSF_IP5 | STATUSF_IP6 | STATUSF_IP7);
 }

 static void cps_smp_finish(void)
 {
 	write_c0_compare(read_c0_count() + (8 * mips_hpt_frequency / HZ));

 #ifdef CONFIG_MIPS_MT_FPAFF
 	/* If we have an FPU, enroll ourselves in the FPU-full mask */
 	if (cpu_has_fpu)
 		cpumask_set_cpu(smp_processor_id(), &mt_fpu_cpumask);
 #endif /* CONFIG_MIPS_MT_FPAFF */

 	local_irq_enable();
 }

 #ifdef CONFIG_HOTPLUG_CPU

 static int cps_cpu_disable(void)
 {
 	unsigned cpu = smp_processor_id();
 	struct core_boot_config *core_cfg;

 	if (!cpu)
 		return -EBUSY;

 	if (!cps_pm_support_state(CPS_PM_POWER_GATED))
 		return -EINVAL;

 	core_cfg = &mips_cps_core_bootcfg[current_cpu_data.core];
 	atomic_sub(1 << cpu_vpe_id(&current_cpu_data), &core_cfg->vpe_mask);
 	smp_mb__after_atomic();
 	set_cpu_online(cpu, false);
 	cpumask_clear_cpu(cpu, &cpu_callin_map);

 	return 0;
 }

 static DECLARE_COMPLETION(cpu_death_chosen);
 static unsigned cpu_death_sibling;
 static enum {
 	CPU_DEATH_HALT,
 	CPU_DEATH_POWER,
 } cpu_death;

 void play_dead(void)
 {
 	unsigned cpu, core;

 	local_irq_disable();
 	idle_task_exit();
 	cpu = smp_processor_id();
 	cpu_death = CPU_DEATH_POWER;

 	if (cpu_has_mipsmt) {
 		core = cpu_data[cpu].core;

 		/* Look for another online VPE within the core */
 		for_each_online_cpu(cpu_death_sibling) {
 			if (cpu_data[cpu_death_sibling].core != core)
 				continue;

 			/*
 			 * There is an online VPE within the core. Just halt
 			 * this TC and leave the core alone.
 			 */
 			cpu_death = CPU_DEATH_HALT;
 			break;
 		}
 	}

 	/* This CPU has chosen its way out */
 	complete(&cpu_death_chosen);

 	if (cpu_death == CPU_DEATH_HALT) {
 		/* Halt this TC */
 		write_c0_tchalt(TCHALT_H);
 		instruction_hazard();
 	} else {
 		/* Power down the core */
 		cps_pm_enter_state(CPS_PM_POWER_GATED);
 	}

 	/* This should never be reached */
 	panic("Failed to offline CPU %u", cpu);
 }

 static void wait_for_sibling_halt(void *ptr_cpu)
 {
 	unsigned cpu = (unsigned long)ptr_cpu;
 	unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]);
 	unsigned halted;
 	unsigned long flags;

 	do {
 		local_irq_save(flags);
 		settc(vpe_id);
 		halted = read_tc_c0_tchalt();
 		local_irq_restore(flags);
 	} while (!(halted & TCHALT_H));
 }

 static void cps_cpu_die(unsigned int cpu)
 {
 	unsigned core = cpu_data[cpu].core;
 	unsigned stat;
 	int err;

 	/* Wait for the cpu to choose its way out */
 	if (!wait_for_completion_timeout(&cpu_death_chosen,
 					 msecs_to_jiffies(5000))) {
 		pr_err("CPU%u: didn't offline\n", cpu);
 		return;
 	}

 	/*
 	 * Now wait for the CPU to actually offline. Without doing this that
 	 * offlining may race with one or more of:
 	 *
 	 *   - Onlining the CPU again.
 	 *   - Powering down the core if another VPE within it is offlined.
 	 *   - A sibling VPE entering a non-coherent state.
 	 *
 	 * In the non-MT halt case (ie. infinite loop) the CPU is doing nothing
 	 * with which we could race, so do nothing.
 	 */
 	if (cpu_death == CPU_DEATH_POWER) {
 		/*
 		 * Wait for the core to enter a powered down or clock gated
 		 * state, the latter happening when a JTAG probe is connected
 		 * in which case the CPC will refuse to power down the core.
 		 */
 		do {
 			mips_cpc_lock_other(core);
 			stat = read_cpc_co_stat_conf();
 			stat &= CPC_Cx_STAT_CONF_SEQSTATE_MSK;
 			mips_cpc_unlock_other();
 		} while (stat != CPC_Cx_STAT_CONF_SEQSTATE_D0 &&
 			 stat != CPC_Cx_STAT_CONF_SEQSTATE_D2 &&
 			 stat != CPC_Cx_STAT_CONF_SEQSTATE_U2);

 		/* Indicate the core is powered off */
 		bitmap_clear(core_power, core, 1);
 	} else if (cpu_has_mipsmt) {
 		/*
 		 * Have a CPU with access to the offlined CPUs registers wait
 		 * for its TC to halt.
 		 */
 		err = smp_call_function_single(cpu_death_sibling,
 					       wait_for_sibling_halt,
 					       (void *)(unsigned long)cpu, 1);
 		if (err)
 			panic("Failed to call remote sibling CPU\n");
 	}
 }

 #endif /* CONFIG_HOTPLUG_CPU */

 static struct plat_smp_ops cps_smp_ops = {
 	.smp_setup		= cps_smp_setup,
 	.prepare_cpus		= cps_prepare_cpus,
 	.boot_secondary		= cps_boot_secondary,
 	.init_secondary		= cps_init_secondary,
 	.smp_finish		= cps_smp_finish,
 	.send_ipi_single	= gic_send_ipi_single,
 	.send_ipi_mask		= gic_send_ipi_mask,
 #ifdef CONFIG_HOTPLUG_CPU
 	.cpu_disable		= cps_cpu_disable,
 	.cpu_die		= cps_cpu_die,
 #endif
 };

 bool mips_cps_smp_in_use(void)
 {
 	extern struct plat_smp_ops *mp_ops;
 	return mp_ops == &cps_smp_ops;
 }

 int register_cps_smp_ops(void)
 {
 	if (!mips_cm_present()) {
 		pr_warn("MIPS CPS SMP unable to proceed without a CM\n");
 		return -ENODEV;
 	}

 	/* check we have a GIC - we need one for IPIs */
 	if (!(read_gcr_gic_status() & CM_GCR_GIC_STATUS_EX_MSK)) {
 		pr_warn("MIPS CPS SMP unable to proceed without a GIC\n");
 		return -ENODEV;
 	}

 	register_smp_ops(&cps_smp_ops);
 	return 0;
 }
	/*
	* Copyright (C) 2013 Imagination Technologies
	* Author: Paul Burton <paul.burton@imgtec.com>
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License as published by the
	* Free Software Foundation; either version 2 of the License, or (at your
	* option) any later version.
	*/

	#include <linux/delay.h>
	#include <linux/io.h>
	#include <linux/irqchip/mips-gic.h>
	#include <linux/sched.h>
	#include <linux/slab.h>
	#include <linux/smp.h>
	#include <linux/types.h>

	#include <asm/bcache.h>
	#include <asm/mips-cm.h>
	#include <asm/mips-cpc.h>
	#include <asm/mips_mt.h>
	#include <asm/mipsregs.h>
	#include <asm/pm-cps.h>
	#include <asm/r4kcache.h>
	#include <asm/smp-cps.h>
	#include <asm/time.h>
	#include <asm/uasm.h>

	static DECLARE_BITMAP(core_power, NR_CPUS);

	struct core_boot_config *mips_cps_core_bootcfg;

	static unsigned core_vpe_count(unsigned core)
	{
	unsigned cfg;

	if (!config_enabled(CONFIG_MIPS_MT_SMP) \|\| !cpu_has_mipsmt)
	return 1;

	mips_cm_lock_other(core, 0);
	cfg = read_gcr_co_config() & CM_GCR_Cx_CONFIG_PVPE_MSK;
	mips_cm_unlock_other();
	return (cfg >> CM_GCR_Cx_CONFIG_PVPE_SHF) + 1;
	}

	static void __init cps_smp_setup(void)
	{
	unsigned int ncores, nvpes, core_vpes;
	int c, v;

	/* Detect & record VPE topology */
	ncores = mips_cm_numcores();
	pr_info("VPE topology ");
	for (c = nvpes = 0; c < ncores; c++) {
	core_vpes = core_vpe_count(c);
	pr_cont("%c%u", c ? ',' : '{', core_vpes);

	/* Use the number of VPEs in core 0 for smp_num_siblings */
	if (!c)
	smp_num_siblings = core_vpes;

	for (v = 0; v < min_t(int, core_vpes, NR_CPUS - nvpes); v++) {
	cpu_data[nvpes + v].core = c;
	#ifdef CONFIG_MIPS_MT_SMP
	cpu_data[nvpes + v].vpe_id = v;
	#endif
	}

	nvpes += core_vpes;
	}
	pr_cont("} total %u\n", nvpes);

	/* Indicate present CPUs (CPU being synonymous with VPE) */
	for (v = 0; v < min_t(unsigned, nvpes, NR_CPUS); v++) {
	set_cpu_possible(v, true);
	set_cpu_present(v, true);
	__cpu_number_map[v] = v;
	__cpu_logical_map[v] = v;
	}

	/* Set a coherent default CCA (CWB) */
	change_c0_config(CONF_CM_CMASK, 0x5);

	/* Core 0 is powered up (we're running on it) */
	bitmap_set(core_power, 0, 1);

	/* Initialise core 0 */
	mips_cps_core_init();

	/* Make core 0 coherent with everything */
	write_gcr_cl_coherence(0xff);

	#ifdef CONFIG_MIPS_MT_FPAFF
	/* If we have an FPU, enroll ourselves in the FPU-full mask */
	if (cpu_has_fpu)
	cpumask_set_cpu(0, &mt_fpu_cpumask);
	#endif /* CONFIG_MIPS_MT_FPAFF */
	}

	static void __init cps_prepare_cpus(unsigned int max_cpus)
	{
	unsigned ncores, core_vpes, c, cca;
	bool cca_unsuitable;
	u32 *entry_code;

	mips_mt_set_cpuoptions();

	/* Detect whether the CCA is unsuited to multi-core SMP */
	cca = read_c0_config() & CONF_CM_CMASK;
	switch (cca) {
	case 0x4: /* CWBE */
	case 0x5: /* CWB */
	/* The CCA is coherent, multi-core is fine */
	cca_unsuitable = false;
	break;

	default:
	/* CCA is not coherent, multi-core is not usable */
	cca_unsuitable = true;
	}

	/* Warn the user if the CCA prevents multi-core */
	ncores = mips_cm_numcores();
	if (cca_unsuitable && ncores > 1) {
	pr_warn("Using only one core due to unsuitable CCA 0x%x\n",
	cca);

	for_each_present_cpu(c) {
	if (cpu_data[c].core)
	set_cpu_present(c, false);
	}
	}

	/*
	* Patch the start of mips_cps_core_entry to provide:
	*
	* s0 = kseg0 CCA
	*/
	entry_code = (u32 *)&mips_cps_core_entry;
	uasm_i_addiu(&entry_code, 16, 0, cca);
	blast_dcache_range((unsigned long)&mips_cps_core_entry,
	(unsigned long)entry_code);
	bc_wback_inv((unsigned long)&mips_cps_core_entry,
	(void )entry_code - (void )&mips_cps_core_entry);
	__sync();

	/* Allocate core boot configuration structs */
	mips_cps_core_bootcfg = kcalloc(ncores, sizeof(*mips_cps_core_bootcfg),
	GFP_KERNEL);
	if (!mips_cps_core_bootcfg) {
	pr_err("Failed to allocate boot config for %u cores\n", ncores);
	goto err_out;
	}

	/* Allocate VPE boot configuration structs */
	for (c = 0; c < ncores; c++) {
	core_vpes = core_vpe_count(c);
	mips_cps_core_bootcfg[c].vpe_config = kcalloc(core_vpes,
	sizeof(*mips_cps_core_bootcfg[c].vpe_config),
	GFP_KERNEL);
	if (!mips_cps_core_bootcfg[c].vpe_config) {
	pr_err("Failed to allocate %u VPE boot configs\n",
	core_vpes);
	goto err_out;
	}
	}

	/* Mark this CPU as booted */
	atomic_set(&mips_cps_core_bootcfg[current_cpu_data.core].vpe_mask,
	1 << cpu_vpe_id(&current_cpu_data));

	return;
	err_out:
	/* Clean up allocations */
	if (mips_cps_core_bootcfg) {
	for (c = 0; c < ncores; c++)
	kfree(mips_cps_core_bootcfg[c].vpe_config);
	kfree(mips_cps_core_bootcfg);
	mips_cps_core_bootcfg = NULL;
	}

	/* Effectively disable SMP by declaring CPUs not present */
	for_each_possible_cpu(c) {
	if (c == 0)
	continue;
	set_cpu_present(c, false);
	}
	}

	static void boot_core(unsigned core)
	{
	u32 access, stat, seq_state;
	unsigned timeout;

	/* Select the appropriate core */
	mips_cm_lock_other(core, 0);

	/* Set its reset vector */
	write_gcr_co_reset_base(CKSEG1ADDR((unsigned long)mips_cps_core_entry));

	/* Ensure its coherency is disabled */
	write_gcr_co_coherence(0);

	/* Start it with the legacy memory map and exception base */
	write_gcr_co_reset_ext_base(CM_GCR_RESET_EXT_BASE_UEB);

	/* Ensure the core can access the GCRs */
	access = read_gcr_access();
	access \|= 1 << (CM_GCR_ACCESS_ACCESSEN_SHF + core);
	write_gcr_access(access);

	if (mips_cpc_present()) {
	/* Reset the core */
	mips_cpc_lock_other(core);
	write_cpc_co_cmd(CPC_Cx_CMD_RESET);

	timeout = 100;
	while (true) {
	stat = read_cpc_co_stat_conf();
	seq_state = stat & CPC_Cx_STAT_CONF_SEQSTATE_MSK;

	/* U6 == coherent execution, ie. the core is up */
	if (seq_state == CPC_Cx_STAT_CONF_SEQSTATE_U6)
	break;

	/* Delay a little while before we start warning */
	if (timeout) {
	timeout--;
	mdelay(10);
	continue;
	}

	pr_warn("Waiting for core %u to start... STAT_CONF=0x%x\n",
	core, stat);
	mdelay(1000);
	}

	mips_cpc_unlock_other();
	} else {
	/* Take the core out of reset */
	write_gcr_co_reset_release(0);
	}

	mips_cm_unlock_other();

	/* The core is now powered up */
	bitmap_set(core_power, core, 1);
	}

	static void remote_vpe_boot(void *dummy)
	{
	mips_cps_boot_vpes();
	}

	static void cps_boot_secondary(int cpu, struct task_struct *idle)
	{
	unsigned core = cpu_data[cpu].core;
	unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]);
	struct core_boot_config *core_cfg = &mips_cps_core_bootcfg[core];
	struct vpe_boot_config *vpe_cfg = &core_cfg->vpe_config[vpe_id];
	unsigned int remote;
	int err;

	vpe_cfg->pc = (unsigned long)&smp_bootstrap;
	vpe_cfg->sp = __KSTK_TOS(idle);
	vpe_cfg->gp = (unsigned long)task_thread_info(idle);

	atomic_or(1 << cpu_vpe_id(&cpu_data[cpu]), &core_cfg->vpe_mask);

	preempt_disable();

	if (!test_bit(core, core_power)) {
	/* Boot a VPE on a powered down core */
	boot_core(core);
	goto out;
	}

	if (core != current_cpu_data.core) {
	/* Boot a VPE on another powered up core */
	for (remote = 0; remote < NR_CPUS; remote++) {
	if (cpu_data[remote].core != core)
	continue;
	if (cpu_online(remote))
	break;
	}
	BUG_ON(remote >= NR_CPUS);

	err = smp_call_function_single(remote, remote_vpe_boot,
	NULL, 1);
	if (err)
	panic("Failed to call remote CPU\n");
	goto out;
	}

	BUG_ON(!cpu_has_mipsmt);

	/* Boot a VPE on this core */
	mips_cps_boot_vpes();
	out:
	preempt_enable();
	}

	static void cps_init_secondary(void)
	{
	/* Disable MT - we only want to run 1 TC per VPE */
	if (cpu_has_mipsmt)
	dmt();

	change_c0_status(ST0_IM, STATUSF_IP2 \| STATUSF_IP3 \| STATUSF_IP4 \|
	STATUSF_IP5 \| STATUSF_IP6 \| STATUSF_IP7);
	}

	static void cps_smp_finish(void)
	{
	write_c0_compare(read_c0_count() + (8 * mips_hpt_frequency / HZ));

	#ifdef CONFIG_MIPS_MT_FPAFF
	/* If we have an FPU, enroll ourselves in the FPU-full mask */
	if (cpu_has_fpu)
	cpumask_set_cpu(smp_processor_id(), &mt_fpu_cpumask);
	#endif /* CONFIG_MIPS_MT_FPAFF */

	local_irq_enable();
	}

	#ifdef CONFIG_HOTPLUG_CPU

	static int cps_cpu_disable(void)
	{
	unsigned cpu = smp_processor_id();
	struct core_boot_config *core_cfg;

	if (!cpu)
	return -EBUSY;

	if (!cps_pm_support_state(CPS_PM_POWER_GATED))
	return -EINVAL;

	core_cfg = &mips_cps_core_bootcfg[current_cpu_data.core];
	atomic_sub(1 << cpu_vpe_id(&current_cpu_data), &core_cfg->vpe_mask);
	smp_mb__after_atomic();
	set_cpu_online(cpu, false);
	cpumask_clear_cpu(cpu, &cpu_callin_map);

	return 0;
	}

	static DECLARE_COMPLETION(cpu_death_chosen);
	static unsigned cpu_death_sibling;
	static enum {
	CPU_DEATH_HALT,
	CPU_DEATH_POWER,
	} cpu_death;

	void play_dead(void)
	{
	unsigned cpu, core;

	local_irq_disable();
	idle_task_exit();
	cpu = smp_processor_id();
	cpu_death = CPU_DEATH_POWER;

	if (cpu_has_mipsmt) {
	core = cpu_data[cpu].core;

	/* Look for another online VPE within the core */
	for_each_online_cpu(cpu_death_sibling) {
	if (cpu_data[cpu_death_sibling].core != core)
	continue;

	/*
	* There is an online VPE within the core. Just halt
	* this TC and leave the core alone.
	*/
	cpu_death = CPU_DEATH_HALT;
	break;
	}
	}

	/* This CPU has chosen its way out */
	complete(&cpu_death_chosen);

	if (cpu_death == CPU_DEATH_HALT) {
	/* Halt this TC */
	write_c0_tchalt(TCHALT_H);
	instruction_hazard();
	} else {
	/* Power down the core */
	cps_pm_enter_state(CPS_PM_POWER_GATED);
	}

	/* This should never be reached */
	panic("Failed to offline CPU %u", cpu);
	}

	static void wait_for_sibling_halt(void *ptr_cpu)
	{
	unsigned cpu = (unsigned long)ptr_cpu;
	unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]);
	unsigned halted;
	unsigned long flags;

	do {
	local_irq_save(flags);
	settc(vpe_id);
	halted = read_tc_c0_tchalt();
	local_irq_restore(flags);
	} while (!(halted & TCHALT_H));
	}

	static void cps_cpu_die(unsigned int cpu)
	{
	unsigned core = cpu_data[cpu].core;
	unsigned stat;
	int err;

	/* Wait for the cpu to choose its way out */
	if (!wait_for_completion_timeout(&cpu_death_chosen,
	msecs_to_jiffies(5000))) {
	pr_err("CPU%u: didn't offline\n", cpu);
	return;
	}

	/*
	* Now wait for the CPU to actually offline. Without doing this that
	* offlining may race with one or more of:
	*
	* - Onlining the CPU again.
	* - Powering down the core if another VPE within it is offlined.
	* - A sibling VPE entering a non-coherent state.
	*
	* In the non-MT halt case (ie. infinite loop) the CPU is doing nothing
	* with which we could race, so do nothing.
	*/
	if (cpu_death == CPU_DEATH_POWER) {
	/*
	* Wait for the core to enter a powered down or clock gated
	* state, the latter happening when a JTAG probe is connected
	* in which case the CPC will refuse to power down the core.
	*/
	do {
	mips_cpc_lock_other(core);
	stat = read_cpc_co_stat_conf();
	stat &= CPC_Cx_STAT_CONF_SEQSTATE_MSK;
	mips_cpc_unlock_other();
	} while (stat != CPC_Cx_STAT_CONF_SEQSTATE_D0 &&
	stat != CPC_Cx_STAT_CONF_SEQSTATE_D2 &&
	stat != CPC_Cx_STAT_CONF_SEQSTATE_U2);

	/* Indicate the core is powered off */
	bitmap_clear(core_power, core, 1);
	} else if (cpu_has_mipsmt) {
	/*
	* Have a CPU with access to the offlined CPUs registers wait
	* for its TC to halt.
	*/
	err = smp_call_function_single(cpu_death_sibling,
	wait_for_sibling_halt,
	(void *)(unsigned long)cpu, 1);
	if (err)
	panic("Failed to call remote sibling CPU\n");
	}
	}

	#endif /* CONFIG_HOTPLUG_CPU */

	static struct plat_smp_ops cps_smp_ops = {
	.smp_setup = cps_smp_setup,
	.prepare_cpus = cps_prepare_cpus,
	.boot_secondary = cps_boot_secondary,
	.init_secondary = cps_init_secondary,
	.smp_finish = cps_smp_finish,
	.send_ipi_single = gic_send_ipi_single,
	.send_ipi_mask = gic_send_ipi_mask,
	#ifdef CONFIG_HOTPLUG_CPU
	.cpu_disable = cps_cpu_disable,
	.cpu_die = cps_cpu_die,
	#endif
	};

	bool mips_cps_smp_in_use(void)
	{
	extern struct plat_smp_ops *mp_ops;
	return mp_ops == &cps_smp_ops;
	}

	int register_cps_smp_ops(void)
	{
	if (!mips_cm_present()) {
	pr_warn("MIPS CPS SMP unable to proceed without a CM\n");
	return -ENODEV;
	}

	/* check we have a GIC - we need one for IPIs */
	if (!(read_gcr_gic_status() & CM_GCR_GIC_STATUS_EX_MSK)) {
	pr_warn("MIPS CPS SMP unable to proceed without a GIC\n");
	return -ENODEV;
	}

	register_smp_ops(&cps_smp_ops);
	return 0;
	}