arch/metag/kernel/irq.c - linux - Git at Google

 /*
  * Linux/Meta general interrupt handling code
  *
  */

 #include <linux/kernel.h>
 #include <linux/interrupt.h>
 #include <linux/init.h>
 #include <linux/irqdomain.h>
 #include <linux/ratelimit.h>

 #include <asm/core_reg.h>
 #include <asm/mach/arch.h>
 #include <asm/uaccess.h>

 #ifdef CONFIG_4KSTACKS
 union irq_ctx {
 	struct thread_info      tinfo;
 	u32                     stack[THREAD_SIZE/sizeof(u32)];
 };

 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
 #endif

 struct irq_domain *root_domain;

 static unsigned int startup_meta_irq(struct irq_data *data)
 {
 	tbi_startup_interrupt(data->hwirq);
 	return 0;
 }

 static void shutdown_meta_irq(struct irq_data *data)
 {
 	tbi_shutdown_interrupt(data->hwirq);
 }

 void do_IRQ(int irq, struct pt_regs *regs)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);
 #ifdef CONFIG_4KSTACKS
 	struct irq_desc *desc;
 	union irq_ctx *curctx, *irqctx;
 	u32 *isp;
 #endif

 	irq_enter();

 	irq = irq_linear_revmap(root_domain, irq);

 #ifdef CONFIG_DEBUG_STACKOVERFLOW
 	/* Debugging check for stack overflow: is there less than 1KB free? */
 	{
 		unsigned long sp;

 		sp = __core_reg_get(A0StP);
 		sp &= THREAD_SIZE - 1;

 		if (unlikely(sp > (THREAD_SIZE - 1024)))
 			pr_err("Stack overflow in do_IRQ: %ld\n", sp);
 	}
 #endif


 #ifdef CONFIG_4KSTACKS
 	curctx = (union irq_ctx *) current_thread_info();
 	irqctx = hardirq_ctx[smp_processor_id()];

 	/*
 	 * this is where we switch to the IRQ stack. However, if we are
 	 * already using the IRQ stack (because we interrupted a hardirq
 	 * handler) we can't do that and just have to keep using the
 	 * current stack (which is the irq stack already after all)
 	 */
 	if (curctx != irqctx) {
 		/* build the stack frame on the IRQ stack */
 		isp = (u32 *) ((char *)irqctx + sizeof(struct thread_info));
 		irqctx->tinfo.task = curctx->tinfo.task;

 		/*
 		 * Copy the softirq bits in preempt_count so that the
 		 * softirq checks work in the hardirq context.
 		 */
 		irqctx->tinfo.preempt_count =
 			(irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
 			(curctx->tinfo.preempt_count & SOFTIRQ_MASK);

 		desc = irq_to_desc(irq);

 		asm volatile (
 			"MOV   D0.5,%0\n"
 			"MOV   D1Ar1,%1\n"
 			"MOV   D1RtP,%2\n"
 			"MOV   D0Ar2,%3\n"
 			"SWAP  A0StP,D0.5\n"
 			"SWAP  PC,D1RtP\n"
 			"MOV   A0StP,D0.5\n"
 			:
 			: "r" (isp), "r" (irq), "r" (desc->handle_irq),
 			  "r" (desc)
 			: "memory", "cc", "D1Ar1", "D0Ar2", "D1Ar3", "D0Ar4",
 			  "D1Ar5", "D0Ar6", "D0Re0", "D1Re0", "D0.4", "D1RtP",
 			  "D0.5"
 			);
 	} else
 #endif
 		generic_handle_irq(irq);

 	irq_exit();

 	set_irq_regs(old_regs);
 }

 #ifdef CONFIG_4KSTACKS

 static char softirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;

 static char hardirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;

 /*
  * allocate per-cpu stacks for hardirq and for softirq processing
  */
 void irq_ctx_init(int cpu)
 {
 	union irq_ctx *irqctx;

 	if (hardirq_ctx[cpu])
 		return;

 	irqctx = (union irq_ctx *) &hardirq_stack[cpu * THREAD_SIZE];
 	irqctx->tinfo.task              = NULL;
 	irqctx->tinfo.exec_domain       = NULL;
 	irqctx->tinfo.cpu               = cpu;
 	irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
 	irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);

 	hardirq_ctx[cpu] = irqctx;

 	irqctx = (union irq_ctx *) &softirq_stack[cpu * THREAD_SIZE];
 	irqctx->tinfo.task              = NULL;
 	irqctx->tinfo.exec_domain       = NULL;
 	irqctx->tinfo.cpu               = cpu;
 	irqctx->tinfo.preempt_count     = 0;
 	irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);

 	softirq_ctx[cpu] = irqctx;

 	pr_info("CPU %u irqstacks, hard=%p soft=%p\n",
 		cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
 }

 void irq_ctx_exit(int cpu)
 {
 	hardirq_ctx[smp_processor_id()] = NULL;
 }

 extern asmlinkage void __do_softirq(void);

 asmlinkage void do_softirq(void)
 {
 	unsigned long flags;
 	struct thread_info *curctx;
 	union irq_ctx *irqctx;
 	u32 *isp;

 	if (in_interrupt())
 		return;

 	local_irq_save(flags);

 	if (local_softirq_pending()) {
 		curctx = current_thread_info();
 		irqctx = softirq_ctx[smp_processor_id()];
 		irqctx->tinfo.task = curctx->task;

 		/* build the stack frame on the softirq stack */
 		isp = (u32 *) ((char *)irqctx + sizeof(struct thread_info));

 		asm volatile (
 			"MOV   D0.5,%0\n"
 			"SWAP  A0StP,D0.5\n"
 			"CALLR D1RtP,___do_softirq\n"
 			"MOV   A0StP,D0.5\n"
 			:
 			: "r" (isp)
 			: "memory", "cc", "D1Ar1", "D0Ar2", "D1Ar3", "D0Ar4",
 			  "D1Ar5", "D0Ar6", "D0Re0", "D1Re0", "D0.4", "D1RtP",
 			  "D0.5"
 			);
 		/*
 		 * Shouldn't happen, we returned above if in_interrupt():
 		 */
 		WARN_ON_ONCE(softirq_count());
 	}

 	local_irq_restore(flags);
 }
 #endif

 static struct irq_chip meta_irq_type = {
 	.name = "META-IRQ",
 	.irq_startup = startup_meta_irq,
 	.irq_shutdown = shutdown_meta_irq,
 };

 /**
  * tbisig_map() - Map a TBI signal number to a virtual IRQ number.
  * @hw:		Number of the TBI signal. Must be in range.
  *
  * Returns:	The virtual IRQ number of the TBI signal number IRQ specified by
  *		@hw.
  */
 int tbisig_map(unsigned int hw)
 {
 	return irq_create_mapping(root_domain, hw);
 }

 /**
  * metag_tbisig_map() - map a tbi signal to a Linux virtual IRQ number
  * @d:		root irq domain
  * @irq:	virtual irq number
  * @hw:		hardware irq number (TBI signal number)
  *
  * This sets up a virtual irq for a specified TBI signal number.
  */
 static int metag_tbisig_map(struct irq_domain *d, unsigned int irq,
 			    irq_hw_number_t hw)
 {
 #ifdef CONFIG_SMP
 	irq_set_chip_and_handler(irq, &meta_irq_type, handle_percpu_irq);
 #else
 	irq_set_chip_and_handler(irq, &meta_irq_type, handle_simple_irq);
 #endif
 	return 0;
 }

 static const struct irq_domain_ops metag_tbisig_domain_ops = {
 	.map = metag_tbisig_map,
 };

 /*
  * void init_IRQ(void)
  *
  * Parameters:	None
  *
  * Returns:	Nothing
  *
  * This function should be called during kernel startup to initialize
  * the IRQ handling routines.
  */
 void __init init_IRQ(void)
 {
 	root_domain = irq_domain_add_linear(NULL, 32,
 					    &metag_tbisig_domain_ops, NULL);
 	if (unlikely(!root_domain))
 		panic("init_IRQ: cannot add root IRQ domain");

 	irq_ctx_init(smp_processor_id());

 	if (machine_desc->init_irq)
 		machine_desc->init_irq();
 }

 int __init arch_probe_nr_irqs(void)
 {
 	if (machine_desc->nr_irqs)
 		nr_irqs = machine_desc->nr_irqs;
 	return 0;
 }

 #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);

 	raw_spin_lock_irq(&desc->lock);
 	if (chip->irq_set_affinity)
 		chip->irq_set_affinity(data, cpumask_of(cpu), false);
 	raw_spin_unlock_irq(&desc->lock);
 }

 /*
  * 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 */
	/*
	* Linux/Meta general interrupt handling code
	*
	*/

	#include <linux/kernel.h>
	#include <linux/interrupt.h>
	#include <linux/init.h>
	#include <linux/irqdomain.h>
	#include <linux/ratelimit.h>

	#include <asm/core_reg.h>
	#include <asm/mach/arch.h>
	#include <asm/uaccess.h>

	#ifdef CONFIG_4KSTACKS
	union irq_ctx {
	struct thread_info tinfo;
	u32 stack[THREAD_SIZE/sizeof(u32)];
	};

	static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
	static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
	#endif

	struct irq_domain *root_domain;

	static unsigned int startup_meta_irq(struct irq_data *data)
	{
	tbi_startup_interrupt(data->hwirq);
	return 0;
	}

	static void shutdown_meta_irq(struct irq_data *data)
	{
	tbi_shutdown_interrupt(data->hwirq);
	}

	void do_IRQ(int irq, struct pt_regs *regs)
	{
	struct pt_regs *old_regs = set_irq_regs(regs);
	#ifdef CONFIG_4KSTACKS
	struct irq_desc *desc;
	union irq_ctx curctx, irqctx;
	u32 *isp;
	#endif

	irq_enter();

	irq = irq_linear_revmap(root_domain, irq);

	#ifdef CONFIG_DEBUG_STACKOVERFLOW
	/* Debugging check for stack overflow: is there less than 1KB free? */
	{
	unsigned long sp;

	sp = __core_reg_get(A0StP);
	sp &= THREAD_SIZE - 1;

	if (unlikely(sp > (THREAD_SIZE - 1024)))
	pr_err("Stack overflow in do_IRQ: %ld\n", sp);
	}
	#endif


	#ifdef CONFIG_4KSTACKS
	curctx = (union irq_ctx *) current_thread_info();
	irqctx = hardirq_ctx[smp_processor_id()];

	/*
	* this is where we switch to the IRQ stack. However, if we are
	* already using the IRQ stack (because we interrupted a hardirq
	* handler) we can't do that and just have to keep using the
	* current stack (which is the irq stack already after all)
	*/
	if (curctx != irqctx) {
	/* build the stack frame on the IRQ stack */
	isp = (u32 ) ((char )irqctx + sizeof(struct thread_info));
	irqctx->tinfo.task = curctx->tinfo.task;

	/*
	* Copy the softirq bits in preempt_count so that the
	* softirq checks work in the hardirq context.
	*/
	irqctx->tinfo.preempt_count =
	(irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) \|
	(curctx->tinfo.preempt_count & SOFTIRQ_MASK);

	desc = irq_to_desc(irq);

	asm volatile (
	"MOV D0.5,%0\n"
	"MOV D1Ar1,%1\n"
	"MOV D1RtP,%2\n"
	"MOV D0Ar2,%3\n"
	"SWAP A0StP,D0.5\n"
	"SWAP PC,D1RtP\n"
	"MOV A0StP,D0.5\n"
	:
	: "r" (isp), "r" (irq), "r" (desc->handle_irq),
	"r" (desc)
	: "memory", "cc", "D1Ar1", "D0Ar2", "D1Ar3", "D0Ar4",
	"D1Ar5", "D0Ar6", "D0Re0", "D1Re0", "D0.4", "D1RtP",
	"D0.5"
	);
	} else
	#endif
	generic_handle_irq(irq);

	irq_exit();

	set_irq_regs(old_regs);
	}

	#ifdef CONFIG_4KSTACKS

	static char softirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;

	static char hardirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;

	/*
	* allocate per-cpu stacks for hardirq and for softirq processing
	*/
	void irq_ctx_init(int cpu)
	{
	union irq_ctx *irqctx;

	if (hardirq_ctx[cpu])
	return;

	irqctx = (union irq_ctx ) &hardirq_stack[cpu THREAD_SIZE];
	irqctx->tinfo.task = NULL;
	irqctx->tinfo.exec_domain = NULL;
	irqctx->tinfo.cpu = cpu;
	irqctx->tinfo.preempt_count = HARDIRQ_OFFSET;
	irqctx->tinfo.addr_limit = MAKE_MM_SEG(0);

	hardirq_ctx[cpu] = irqctx;

	irqctx = (union irq_ctx ) &softirq_stack[cpu THREAD_SIZE];
	irqctx->tinfo.task = NULL;
	irqctx->tinfo.exec_domain = NULL;
	irqctx->tinfo.cpu = cpu;
	irqctx->tinfo.preempt_count = 0;
	irqctx->tinfo.addr_limit = MAKE_MM_SEG(0);

	softirq_ctx[cpu] = irqctx;

	pr_info("CPU %u irqstacks, hard=%p soft=%p\n",
	cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
	}

	void irq_ctx_exit(int cpu)
	{
	hardirq_ctx[smp_processor_id()] = NULL;
	}

	extern asmlinkage void __do_softirq(void);

	asmlinkage void do_softirq(void)
	{
	unsigned long flags;
	struct thread_info *curctx;
	union irq_ctx *irqctx;
	u32 *isp;

	if (in_interrupt())
	return;

	local_irq_save(flags);

	if (local_softirq_pending()) {
	curctx = current_thread_info();
	irqctx = softirq_ctx[smp_processor_id()];
	irqctx->tinfo.task = curctx->task;

	/* build the stack frame on the softirq stack */
	isp = (u32 ) ((char )irqctx + sizeof(struct thread_info));

	asm volatile (
	"MOV D0.5,%0\n"
	"SWAP A0StP,D0.5\n"
	"CALLR D1RtP,___do_softirq\n"
	"MOV A0StP,D0.5\n"
	:
	: "r" (isp)
	: "memory", "cc", "D1Ar1", "D0Ar2", "D1Ar3", "D0Ar4",
	"D1Ar5", "D0Ar6", "D0Re0", "D1Re0", "D0.4", "D1RtP",
	"D0.5"
	);
	/*
	* Shouldn't happen, we returned above if in_interrupt():
	*/
	WARN_ON_ONCE(softirq_count());
	}

	local_irq_restore(flags);
	}
	#endif

	static struct irq_chip meta_irq_type = {
	.name = "META-IRQ",
	.irq_startup = startup_meta_irq,
	.irq_shutdown = shutdown_meta_irq,
	};

	/**
	* tbisig_map() - Map a TBI signal number to a virtual IRQ number.
	* @hw: Number of the TBI signal. Must be in range.
	*
	* Returns: The virtual IRQ number of the TBI signal number IRQ specified by
	* @hw.
	*/
	int tbisig_map(unsigned int hw)
	{
	return irq_create_mapping(root_domain, hw);
	}

	/**
	* metag_tbisig_map() - map a tbi signal to a Linux virtual IRQ number
	* @d: root irq domain
	* @irq: virtual irq number
	* @hw: hardware irq number (TBI signal number)
	*
	* This sets up a virtual irq for a specified TBI signal number.
	*/
	static int metag_tbisig_map(struct irq_domain *d, unsigned int irq,
	irq_hw_number_t hw)
	{
	#ifdef CONFIG_SMP
	irq_set_chip_and_handler(irq, &meta_irq_type, handle_percpu_irq);
	#else
	irq_set_chip_and_handler(irq, &meta_irq_type, handle_simple_irq);
	#endif
	return 0;
	}

	static const struct irq_domain_ops metag_tbisig_domain_ops = {
	.map = metag_tbisig_map,
	};

	/*
	* void init_IRQ(void)
	*
	* Parameters: None
	*
	* Returns: Nothing
	*
	* This function should be called during kernel startup to initialize
	* the IRQ handling routines.
	*/
	void __init init_IRQ(void)
	{
	root_domain = irq_domain_add_linear(NULL, 32,
	&metag_tbisig_domain_ops, NULL);
	if (unlikely(!root_domain))
	panic("init_IRQ: cannot add root IRQ domain");

	irq_ctx_init(smp_processor_id());

	if (machine_desc->init_irq)
	machine_desc->init_irq();
	}

	int __init arch_probe_nr_irqs(void)
	{
	if (machine_desc->nr_irqs)
	nr_irqs = machine_desc->nr_irqs;
	return 0;
	}

	#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);

	raw_spin_lock_irq(&desc->lock);
	if (chip->irq_set_affinity)
	chip->irq_set_affinity(data, cpumask_of(cpu), false);
	raw_spin_unlock_irq(&desc->lock);
	}

	/*
	* 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 */