[RFC] preliminary support for sparse IRQ
Eric Miao
eric.y.miao at gmail.com
Mon Dec 28 00:03:37 EST 2009
commit 0dfd0ec8edf8a704d88903ba94c5dc377008e56c
Author: Eric Miao <eric.y.miao at gmail.com>
Date: Mon Dec 28 12:59:59 2009 +0800
[ARM] preliminary support for sparse IRQ
So to allow NR_IRQS to be dynamic and platforms to specify the number
of IRQs really needed.
Signed-off-by: Eric Miao <eric.y.miao at gmail.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 233a222..d57b5c3 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -917,6 +917,18 @@ config ARM_ERRATA_460075
ACTLR register. Note that setting specific bits in the ACTLR register
may not be available in non-secure mode.
+config SPARSE_IRQ
+ bool "Support sparse irq numbering"
+ depends on EXPERIMENTAL
+ help
+ This enables support for sparse irqs. This is useful in general
+ as most CPUs have a fairly sparse array of IRQ vectors, which
+ the irq_desc then maps directly on to. Systems with a high
+ number of off-chip IRQs will want to treat this as
+ experimental until they have been independently verified.
+
+ If you don't know what to do here, say N.
+
endmenu
source "arch/arm/common/Kconfig"
diff --git a/arch/arm/include/asm/irq.h b/arch/arm/include/asm/irq.h
index 328f14a..a1ea728 100644
--- a/arch/arm/include/asm/irq.h
+++ b/arch/arm/include/asm/irq.h
@@ -7,6 +7,8 @@
#define irq_canonicalize(i) (i)
#endif
+#define NR_IRQS_LEGACY 16
+
/*
* Use this value to indicate lack of interrupt
* capability
diff --git a/arch/arm/include/asm/mach/arch.h b/arch/arm/include/asm/mach/arch.h
index c59842d..5ee6f85 100644
--- a/arch/arm/include/asm/mach/arch.h
+++ b/arch/arm/include/asm/mach/arch.h
@@ -20,6 +20,7 @@ struct machine_desc {
* by assembler code in head.S, head-common.S
*/
unsigned int nr; /* architecture number */
+ unsigned int nr_irqs; /* number of IRQs */
unsigned int phys_io; /* start of physical io */
unsigned int io_pg_offst; /* byte offset for io
* page tabe entry */
diff --git a/arch/arm/include/asm/mach/irq.h b/arch/arm/include/asm/mach/irq.h
index 8920b2d..ce3eee9 100644
--- a/arch/arm/include/asm/mach/irq.h
+++ b/arch/arm/include/asm/mach/irq.h
@@ -17,6 +17,7 @@ struct seq_file;
/*
* This is internal. Do not use it.
*/
+extern unsigned int arch_nr_irqs;
extern void (*init_arch_irq)(void);
extern void init_FIQ(void);
extern int show_fiq_list(struct seq_file *, void *);
diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c
index b7cb45b..6b6b4ef 100644
--- a/arch/arm/kernel/irq.c
+++ b/arch/arm/kernel/irq.c
@@ -48,12 +48,14 @@
#define irq_finish(irq) do { } while (0)
#endif
+unsigned int arch_nr_irqs;
void (*init_arch_irq)(void) __initdata = NULL;
unsigned long irq_err_count;
int show_interrupts(struct seq_file *p, void *v)
{
int i = *(loff_t *) v, cpu;
+ struct irq_desc *desc;
struct irqaction * action;
unsigned long flags;
@@ -68,24 +70,25 @@ int show_interrupts(struct seq_file *p, void *v)
seq_putc(p, '\n');
}
- if (i < NR_IRQS) {
- raw_spin_lock_irqsave(&irq_desc[i].lock, flags);
- action = irq_desc[i].action;
+ if (i < nr_irqs) {
+ desc = irq_to_desc(i);
+ raw_spin_lock_irqsave(&desc->lock, flags);
+ action = desc->action;
if (!action)
goto unlock;
seq_printf(p, "%3d: ", i);
for_each_present_cpu(cpu)
seq_printf(p, "%10u ", kstat_irqs_cpu(i, cpu));
- seq_printf(p, " %10s", irq_desc[i].chip->name ? : "-");
+ seq_printf(p, " %10s", desc->chip->name ? : "-");
seq_printf(p, " %s", action->name);
for (action = action->next; action; action = action->next)
seq_printf(p, ", %s", action->name);
seq_putc(p, '\n');
unlock:
- raw_spin_unlock_irqrestore(&irq_desc[i].lock, flags);
- } else if (i == NR_IRQS) {
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+ } else if (i == nr_irqs) {
#ifdef CONFIG_FIQ
show_fiq_list(p, v);
#endif
@@ -113,7 +116,7 @@ asmlinkage void __exception asm_do_IRQ(unsigned
int irq, struct pt_regs *regs)
* Some hardware gives randomly wrong interrupts. Rather
* than crashing, do something sensible.
*/
- if (unlikely(irq >= NR_IRQS)) {
+ if (unlikely(irq >= nr_irqs)) {
if (printk_ratelimit())
printk(KERN_WARNING "Bad IRQ%u\n", irq);
ack_bad_irq(irq);
@@ -133,12 +136,12 @@ void set_irq_flags(unsigned int irq, unsigned int iflags)
struct irq_desc *desc;
unsigned long flags;
- if (irq >= NR_IRQS) {
+ if (irq >= nr_irqs) {
printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
return;
}
- desc = irq_desc + irq;
+ desc = irq_to_desc(irq);
raw_spin_lock_irqsave(&desc->lock, flags);
desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
if (iflags & IRQF_VALID)
@@ -152,14 +155,25 @@ void set_irq_flags(unsigned int irq, unsigned int iflags)
void __init init_IRQ(void)
{
+ struct irq_desc *desc;
int irq;
- for (irq = 0; irq < NR_IRQS; irq++)
- irq_desc[irq].status |= IRQ_NOREQUEST | IRQ_NOPROBE;
+ for (irq = 0; irq < nr_irqs; irq++) {
+ desc = irq_to_desc_alloc_node(irq, 0);
+ desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
+ }
init_arch_irq();
}
+#ifdef CONFIG_SPARSE_IRQ
+int __init arch_probe_nr_irqs(void)
+{
+ nr_irqs = arch_nr_irqs ? arch_nr_irqs : NR_IRQS;
+ return 0;
+}
+#endif
+
#ifdef CONFIG_HOTPLUG_CPU
static void route_irq(struct irq_desc *desc, unsigned int irq,
unsigned int cpu)
@@ -179,10 +193,9 @@ static void route_irq(struct irq_desc *desc,
unsigned int irq, unsigned int cpu)
void migrate_irqs(void)
{
unsigned int i, cpu = smp_processor_id();
+ struct irq_desc *desc;
- for (i = 0; i < NR_IRQS; i++) {
- struct irq_desc *desc = irq_desc + i;
-
+ for_each_irq_desc(i, desc) {
if (desc->node == cpu) {
unsigned int newcpu = cpumask_any_and(desc->affinity,
cpu_online_mask);
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index c6c57b6..747f4ad 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -629,7 +629,7 @@ __tagtable(ATAG_REVISION, parse_tag_revision);
static int __init parse_tag_cmdline(const struct tag *tag)
{
- strlcpy(default_command_line, tag->u.cmdline.cmdline, COMMAND_LINE_SIZE);
+ //strlcpy(default_command_line, tag->u.cmdline.cmdline, COMMAND_LINE_SIZE);
return 0;
}
@@ -755,6 +755,7 @@ void __init setup_arch(char **cmdline_p)
/*
* Set up various architecture-specific pointers
*/
+ arch_nr_irqs = mdesc->nr_irqs;
init_arch_irq = mdesc->init_irq;
system_timer = mdesc->timer;
init_machine = mdesc->init_machine;
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