xtensa: implement CPU hotplug (49b424fe) · Commits · e / devices / android_kernel_fairphone_FP3

arch/xtensa/Kconfig

+9 −0

Original line number	Original line	Diff line number	Diff line
	@@ -140,6 +140,15 @@ config NR_CPUS
	range 2 32		range 2 32
	default "4"		default "4"

			config HOTPLUG_CPU
			bool "Enable CPU hotplug support"
			depends on SMP
			help
			Say Y here to allow turning CPUs off and on. CPUs can be
			controlled through /sys/devices/system/cpu.

			Say N if you want to disable CPU hotplug.

	config MATH_EMULATION		config MATH_EMULATION
	bool "Math emulation"		bool "Math emulation"
	help		help

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -45,6 +45,7 @@ static __inline__ int irq_canonicalize(int irq)
	struct irqaction;		struct irqaction;
	struct irq_domain;		struct irq_domain;

			void migrate_irqs(void);
	int xtensa_irq_domain_xlate(const u32 *intspec, unsigned int intsize,		int xtensa_irq_domain_xlate(const u32 *intspec, unsigned int intsize,
	unsigned long int_irq, unsigned long ext_irq,		unsigned long int_irq, unsigned long ext_irq,
	unsigned long out_hwirq, unsigned int out_type);		unsigned long out_hwirq, unsigned int out_type);

+9 −0

Original line number	Original line	Diff line number	Diff line
	@@ -29,6 +29,15 @@ void ipi_init(void);
	struct seq_file;		struct seq_file;
	void show_ipi_list(struct seq_file *p, int prec);		void show_ipi_list(struct seq_file *p, int prec);

			#ifdef CONFIG_HOTPLUG_CPU

			void __cpu_die(unsigned int cpu);
			int __cpu_disable(void);
			void cpu_die(void);
			void cpu_restart(void);

			#endif /* CONFIG_HOTPLUG_CPU */

	#endif /* CONFIG_SMP */		#endif /* CONFIG_SMP */

	#endif /* _XTENSA_SMP_H */		#endif /* _XTENSA_SMP_H */

+50 −1

Original line number	Original line	Diff line number	Diff line
	@@ -103,7 +103,7 @@ _SetupMMU:

	ENDPROC(_start)		ENDPROC(_start)

	__INIT		__REF
	.literal_position		.literal_position

	ENTRY(_startup)		ENTRY(_startup)
	@@ -302,6 +302,55 @@ should_never_return:

	ENDPROC(_startup)		ENDPROC(_startup)

			#ifdef CONFIG_HOTPLUG_CPU

			ENTRY(cpu_restart)

			#if XCHAL_DCACHE_IS_WRITEBACK
			___flush_invalidate_dcache_all a2 a3
			#else
			___invalidate_dcache_all a2 a3
			#endif
			memw
			movi a2, CCON # MX External Register to Configure Cache
			movi a3, 0
			wer a3, a2
			extw

			rsr a0, prid
			neg a2, a0
			movi a3, cpu_start_id
			s32i a2, a3, 0
			#if XCHAL_DCACHE_IS_WRITEBACK
			dhwbi a3, 0
			#endif
			1:
			l32i a2, a3, 0
			dhi a3, 0
			bne a2, a0, 1b

			/*
			* Initialize WB, WS, and clear PS.EXCM (to allow loop instructions).
			* Set Interrupt Level just below XCHAL_DEBUGLEVEL to allow
			* xt-gdb to single step via DEBUG exceptions received directly
			* by ocd.
			*/
			movi a1, 1
			movi a0, 0
			wsr a1, windowstart
			wsr a0, windowbase
			rsync

			movi a1, LOCKLEVEL
			wsr a1, ps
			rsync

			j _startup

			ENDPROC(cpu_restart)

			#endif /* CONFIG_HOTPLUG_CPU */

	/*		/*
	* DATA section		* DATA section
	*/		*/

+49 −0

Original line number	Original line	Diff line number	Diff line
	@@ -153,3 +153,52 @@ void __init init_IRQ(void)
	#endif		#endif
	variant_init_irq();		variant_init_irq();
	}		}

			#ifdef CONFIG_HOTPLUG_CPU
			static void route_irq(struct irq_data *data, unsigned int irq, unsigned int cpu)
			{
			struct irq_desc *desc = irq_to_desc(irq);
			struct irq_chip *chip = irq_data_get_irq_chip(data);
			unsigned long flags;

			raw_spin_lock_irqsave(&desc->lock, flags);
			if (chip->irq_set_affinity)
			chip->irq_set_affinity(data, cpumask_of(cpu), false);
			raw_spin_unlock_irqrestore(&desc->lock, flags);
			}

			/*
			* The CPU has been marked offline. Migrate IRQs off this CPU. If
			* the affinity settings do not allow other CPUs, force them onto any
			* available CPU.
			*/
			void migrate_irqs(void)
			{
			unsigned int i, cpu = smp_processor_id();
			struct irq_desc *desc;

			for_each_irq_desc(i, desc) {
			struct irq_data *data = irq_desc_get_irq_data(desc);
			unsigned int newcpu;

			if (irqd_is_per_cpu(data))
			continue;

			if (!cpumask_test_cpu(cpu, data->affinity))
			continue;

			newcpu = cpumask_any_and(data->affinity, cpu_online_mask);

			if (newcpu >= nr_cpu_ids) {
			pr_info_ratelimited("IRQ%u no longer affine to CPU%u\n",
			i, cpu);

			cpumask_setall(data->affinity);
			newcpu = cpumask_any_and(data->affinity,
			cpu_online_mask);
			}

			route_irq(data, i, newcpu);
			}
			}
			#endif /* CONFIG_HOTPLUG_CPU */