linux/arch/xtensa/kernel/irq.c
Max Filippov da844a8177 xtensa: add device trees support
Device trees allow specification of hardware topology and device
parameters at runtime instead of hard-coding them in platform setup
code. This allows running single binary kernel on a range of compatible
boards.

New boot parameters tag BP_TAG_FDT is allocated and a pointer to flat
device tree is passed in it.

Note that current interrupt mapping scheme uses single cell for
interrupt identification. That means that IRQ numbers used in DTS must
be CPU internal IRQ numbers, not external. It is possible to extend
interrupt identification to two cells, and use second cell to tell
external IRQ numbers form internal. That would allow to use single DTS
on multiple boards with different mapping of external IRQ numbers.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
2012-12-18 21:10:23 -08:00

218 lines
5.1 KiB
C

/*
* linux/arch/xtensa/kernel/irq.c
*
* Xtensa built-in interrupt controller and some generic functions copied
* from i386.
*
* Copyright (C) 2002 - 2006 Tensilica, Inc.
* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
*
*
* Chris Zankel <chris@zankel.net>
* Kevin Chea
*
*/
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel_stat.h>
#include <linux/irqdomain.h>
#include <linux/of.h>
#include <asm/uaccess.h>
#include <asm/platform.h>
static unsigned int cached_irq_mask;
atomic_t irq_err_count;
static struct irq_domain *root_domain;
/*
* do_IRQ handles all normal device IRQ's (the special
* SMP cross-CPU interrupts have their own specific
* handlers).
*/
asmlinkage void do_IRQ(int hwirq, struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);
int irq = irq_find_mapping(root_domain, hwirq);
if (hwirq >= NR_IRQS) {
printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
__func__, hwirq);
}
irq_enter();
#ifdef CONFIG_DEBUG_STACKOVERFLOW
/* Debugging check for stack overflow: is there less than 1KB free? */
{
unsigned long sp;
__asm__ __volatile__ ("mov %0, a1\n" : "=a" (sp));
sp &= THREAD_SIZE - 1;
if (unlikely(sp < (sizeof(thread_info) + 1024)))
printk("Stack overflow in do_IRQ: %ld\n",
sp - sizeof(struct thread_info));
}
#endif
generic_handle_irq(irq);
irq_exit();
set_irq_regs(old_regs);
}
int arch_show_interrupts(struct seq_file *p, int prec)
{
seq_printf(p, "%*s: ", prec, "ERR");
seq_printf(p, "%10u\n", atomic_read(&irq_err_count));
return 0;
}
static void xtensa_irq_mask(struct irq_data *d)
{
cached_irq_mask &= ~(1 << d->hwirq);
set_sr (cached_irq_mask, intenable);
}
static void xtensa_irq_unmask(struct irq_data *d)
{
cached_irq_mask |= 1 << d->hwirq;
set_sr (cached_irq_mask, intenable);
}
static void xtensa_irq_enable(struct irq_data *d)
{
variant_irq_enable(d->hwirq);
xtensa_irq_unmask(d);
}
static void xtensa_irq_disable(struct irq_data *d)
{
xtensa_irq_mask(d);
variant_irq_disable(d->hwirq);
}
static void xtensa_irq_ack(struct irq_data *d)
{
set_sr(1 << d->hwirq, intclear);
}
static int xtensa_irq_retrigger(struct irq_data *d)
{
set_sr(1 << d->hwirq, intset);
return 1;
}
static struct irq_chip xtensa_irq_chip = {
.name = "xtensa",
.irq_enable = xtensa_irq_enable,
.irq_disable = xtensa_irq_disable,
.irq_mask = xtensa_irq_mask,
.irq_unmask = xtensa_irq_unmask,
.irq_ack = xtensa_irq_ack,
.irq_retrigger = xtensa_irq_retrigger,
};
static int xtensa_irq_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hw)
{
u32 mask = 1 << hw;
if (mask & XCHAL_INTTYPE_MASK_SOFTWARE) {
irq_set_chip_and_handler_name(irq, &xtensa_irq_chip,
handle_simple_irq, "level");
irq_set_status_flags(irq, IRQ_LEVEL);
} else if (mask & XCHAL_INTTYPE_MASK_EXTERN_EDGE) {
irq_set_chip_and_handler_name(irq, &xtensa_irq_chip,
handle_edge_irq, "edge");
irq_clear_status_flags(irq, IRQ_LEVEL);
} else if (mask & XCHAL_INTTYPE_MASK_EXTERN_LEVEL) {
irq_set_chip_and_handler_name(irq, &xtensa_irq_chip,
handle_level_irq, "level");
irq_set_status_flags(irq, IRQ_LEVEL);
} else if (mask & XCHAL_INTTYPE_MASK_TIMER) {
irq_set_chip_and_handler_name(irq, &xtensa_irq_chip,
handle_edge_irq, "edge");
irq_clear_status_flags(irq, IRQ_LEVEL);
} else {/* XCHAL_INTTYPE_MASK_WRITE_ERROR */
/* XCHAL_INTTYPE_MASK_NMI */
irq_set_chip_and_handler_name(irq, &xtensa_irq_chip,
handle_level_irq, "level");
irq_set_status_flags(irq, IRQ_LEVEL);
}
return 0;
}
static unsigned map_ext_irq(unsigned ext_irq)
{
unsigned mask = XCHAL_INTTYPE_MASK_EXTERN_EDGE |
XCHAL_INTTYPE_MASK_EXTERN_LEVEL;
unsigned i;
for (i = 0; mask; ++i, mask >>= 1) {
if ((mask & 1) && ext_irq-- == 0)
return i;
}
return XCHAL_NUM_INTERRUPTS;
}
/*
* Device Tree IRQ specifier translation function which works with one or
* two cell bindings. First cell value maps directly to the hwirq number.
* Second cell if present specifies whether hwirq number is external (1) or
* internal (0).
*/
int xtensa_irq_domain_xlate(struct irq_domain *d, struct device_node *ctrlr,
const u32 *intspec, unsigned int intsize,
unsigned long *out_hwirq, unsigned int *out_type)
{
if (WARN_ON(intsize < 1 || intsize > 2))
return -EINVAL;
if (intsize == 2 && intspec[1] == 1) {
unsigned int_irq = map_ext_irq(intspec[0]);
if (int_irq < XCHAL_NUM_INTERRUPTS)
*out_hwirq = int_irq;
else
return -EINVAL;
} else {
*out_hwirq = intspec[0];
}
*out_type = IRQ_TYPE_NONE;
return 0;
}
static const struct irq_domain_ops xtensa_irq_domain_ops = {
.xlate = xtensa_irq_domain_xlate,
.map = xtensa_irq_map,
};
void __init init_IRQ(void)
{
struct device_node *intc = NULL;
cached_irq_mask = 0;
set_sr(~0, intclear);
#ifdef CONFIG_OF
/* The interrupt controller device node is mandatory */
intc = of_find_compatible_node(NULL, NULL, "xtensa,pic");
BUG_ON(!intc);
root_domain = irq_domain_add_linear(intc, NR_IRQS,
&xtensa_irq_domain_ops, NULL);
#else
root_domain = irq_domain_add_legacy(intc, NR_IRQS, 0, 0,
&xtensa_irq_domain_ops, NULL);
#endif
irq_set_default_host(root_domain);
variant_init_irq();
}