Commit 63047ea3 authored by James Hogan's avatar James Hogan
Browse files

metag: IRQ handling



Add core IRQ handling for metag. The code in irq.c exposes the TBX
signal numbers as Linux IRQs.
Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
parent ac919f08
#ifndef __ASM_METAG_IRQ_H
#define __ASM_METAG_IRQ_H
#ifdef CONFIG_4KSTACKS
extern void irq_ctx_init(int cpu);
extern void irq_ctx_exit(int cpu);
# define __ARCH_HAS_DO_SOFTIRQ
#else
# define irq_ctx_init(cpu) do { } while (0)
# define irq_ctx_exit(cpu) do { } while (0)
#endif
void tbi_startup_interrupt(int);
void tbi_shutdown_interrupt(int);
struct pt_regs;
int tbisig_map(unsigned int hw);
extern void do_IRQ(int irq, struct pt_regs *regs);
#ifdef CONFIG_METAG_SUSPEND_MEM
int traps_save_context(void);
int traps_restore_context(void);
#endif
#include <asm-generic/irq.h>
#ifdef CONFIG_HOTPLUG_CPU
extern void migrate_irqs(void);
#endif
#endif /* __ASM_METAG_IRQ_H */
/*
* IRQ flags handling
*
* This file gets included from lowlevel asm headers too, to provide
* wrapped versions of the local_irq_*() APIs, based on the
* raw_local_irq_*() functions from the lowlevel headers.
*/
#ifndef _ASM_IRQFLAGS_H
#define _ASM_IRQFLAGS_H
#ifndef __ASSEMBLY__
#include <asm/core_reg.h>
#include <asm/metag_regs.h>
#define INTS_OFF_MASK TXSTATI_BGNDHALT_BIT
#ifdef CONFIG_SMP
extern unsigned int get_trigger_mask(void);
#else
extern unsigned int global_trigger_mask;
static inline unsigned int get_trigger_mask(void)
{
return global_trigger_mask;
}
#endif
static inline unsigned long arch_local_save_flags(void)
{
return __core_reg_get(TXMASKI);
}
static inline int arch_irqs_disabled_flags(unsigned long flags)
{
return (flags & ~INTS_OFF_MASK) == 0;
}
static inline int arch_irqs_disabled(void)
{
unsigned long flags = arch_local_save_flags();
return arch_irqs_disabled_flags(flags);
}
static inline unsigned long __irqs_disabled(void)
{
/*
* We shouldn't enable exceptions if they are not already
* enabled. This is required for chancalls to work correctly.
*/
return arch_local_save_flags() & INTS_OFF_MASK;
}
/*
* For spinlocks, etc:
*/
static inline unsigned long arch_local_irq_save(void)
{
unsigned long flags = __irqs_disabled();
asm volatile("SWAP %0,TXMASKI\n" : "=r" (flags) : "0" (flags)
: "memory");
return flags;
}
static inline void arch_local_irq_restore(unsigned long flags)
{
asm volatile("MOV TXMASKI,%0\n" : : "r" (flags) : "memory");
}
static inline void arch_local_irq_disable(void)
{
unsigned long flags = __irqs_disabled();
asm volatile("MOV TXMASKI,%0\n" : : "r" (flags) : "memory");
}
static inline void arch_local_irq_enable(void)
{
#ifdef CONFIG_SMP
preempt_disable();
arch_local_irq_restore(get_trigger_mask());
preempt_enable_no_resched();
#else
arch_local_irq_restore(get_trigger_mask());
#endif
}
#endif /* (__ASSEMBLY__) */
#endif /* !(_ASM_IRQFLAGS_H) */
/*
* 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 */
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