open_pic.c

一个2.4.21版本的嵌入式linux内核

/*
 *  arch/ppc/kernel/open_pic.c -- OpenPIC Interrupt Handling
 *
 *  Copyright (C) 1997 Geert Uytterhoeven
 *
 *  This file is subject to the terms and conditions of the GNU General Public
 *  License.  See the file COPYING in the main directory of this archive
 *  for more details.
 */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <asm/ptrace.h>
#include <asm/signal.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/prom.h>
#include <asm/sections.h>
#include <asm/open_pic.h>
#include <asm/i8259.h>

#include "open_pic_defs.h"

void* OpenPIC_Addr;
static volatile struct OpenPIC *OpenPIC = NULL;
/*
 * We define OpenPIC_InitSenses table thusly:
 * bit 0x1: sense, 0 for edge and 1 for level.
 * bit 0x2: polarity, 0 for negative, 1 for positive.
 */
u_int OpenPIC_NumInitSenses __initdata = 0;
u_char *OpenPIC_InitSenses __initdata = NULL;
extern int use_of_interrupt_tree;

static u_int NumProcessors;
static u_int NumSources;
static int open_pic_irq_offset;
static volatile OpenPIC_Source *ISR[NR_IRQS];
static int openpic_cascade_irq = -1;
static int (*openpic_cascade_fn)(struct pt_regs *);

/* Global Operations */
static void openpic_disable_8259_pass_through(void);
static void openpic_set_priority(u_int pri);
static void openpic_set_spurious(u_int vector);

#ifdef CONFIG_SMP
/* Interprocessor Interrupts */
static void openpic_initipi(u_int ipi, u_int pri, u_int vector);
static void openpic_ipi_action(int cpl, void *dev_id, struct pt_regs *regs);
#endif

/* Timer Interrupts */
static void openpic_inittimer(u_int timer, u_int pri, u_int vector);
static void openpic_maptimer(u_int timer, u_int cpumask);

/* Interrupt Sources */
static void openpic_enable_irq(u_int irq);
static void openpic_disable_irq(u_int irq);
static void openpic_initirq(u_int irq, u_int pri, u_int vector, int polarity,
			    int is_level);
static void openpic_mapirq(u_int irq, u_int cpumask, u_int keepmask);

/*
 * These functions are not used but the code is kept here
 * for completeness and future reference.
 */
static void openpic_reset(void);
#ifdef notused
static void openpic_enable_8259_pass_through(void);
static u_int openpic_get_priority(void);
static u_int openpic_get_spurious(void);
static void openpic_set_sense(u_int irq, int sense);
#endif /* notused */

/*
 * Description of the openpic for the higher-level irq code
 */
static void openpic_end_irq(unsigned int irq_nr);
static void openpic_ack_irq(unsigned int irq_nr);
static void openpic_set_affinity(unsigned int irq_nr, unsigned long cpumask);

struct hw_interrupt_type open_pic = {
	" OpenPIC  ",
	NULL,
	NULL,
	openpic_enable_irq,
	openpic_disable_irq,
	openpic_ack_irq,
	openpic_end_irq,
	openpic_set_affinity
};

#ifdef CONFIG_SMP
static void openpic_end_ipi(unsigned int irq_nr);
static void openpic_ack_ipi(unsigned int irq_nr);
static void openpic_enable_ipi(unsigned int irq_nr);
static void openpic_disable_ipi(unsigned int irq_nr);

struct hw_interrupt_type open_pic_ipi = {
	" OpenPIC  ",
	NULL,
	NULL,
	openpic_enable_ipi,
	openpic_disable_ipi,
	openpic_ack_ipi,
	openpic_end_ipi,
	0
};
#endif /* CONFIG_SMP */

/*
 *  Accesses to the current processor's openpic registers
 */
#ifdef CONFIG_SMP
#define THIS_CPU		Processor[cpu]
#define DECL_THIS_CPU		int cpu = smp_hw_index[smp_processor_id()]
#define CHECK_THIS_CPU		check_arg_cpu(cpu)
#else
#define THIS_CPU		Processor[0]
#define DECL_THIS_CPU
#define CHECK_THIS_CPU
#endif /* CONFIG_SMP */

#if 1
#define check_arg_ipi(ipi) \
    if (ipi < 0 || ipi >= OPENPIC_NUM_IPI) \
	printk("open_pic.c:%d: illegal ipi %d\n", __LINE__, ipi);
#define check_arg_timer(timer) \
    if (timer < 0 || timer >= OPENPIC_NUM_TIMERS) \
	printk("open_pic.c:%d: illegal timer %d\n", __LINE__, timer);
#define check_arg_vec(vec) \
    if (vec < 0 || vec >= OPENPIC_NUM_VECTORS) \
	printk("open_pic.c:%d: illegal vector %d\n", __LINE__, vec);
#define check_arg_pri(pri) \
    if (pri < 0 || pri >= OPENPIC_NUM_PRI) \
	printk("open_pic.c:%d: illegal priority %d\n", __LINE__, pri);
/*
 * Print out a backtrace if it's out of range, since if it's larger than NR_IRQ's
 * data has probably been corrupted and we're going to panic or deadlock later
 * anyway --Troy
 */
extern unsigned long* _get_SP(void);
#define check_arg_irq(irq) \
    if (irq < open_pic_irq_offset || irq >= NumSources+open_pic_irq_offset \
	|| ISR[irq - open_pic_irq_offset] == 0) { \
      printk("open_pic.c:%d: illegal irq %d\n", __LINE__, irq); \
      print_backtrace(_get_SP()); }
#define check_arg_cpu(cpu) \
    if (cpu < 0 || cpu >= NumProcessors){ \
	printk("open_pic.c:%d: illegal cpu %d\n", __LINE__, cpu); \
	print_backtrace(_get_SP()); }
#else
#define check_arg_ipi(ipi)	do {} while (0)
#define check_arg_timer(timer)	do {} while (0)
#define check_arg_vec(vec)	do {} while (0)
#define check_arg_pri(pri)	do {} while (0)
#define check_arg_irq(irq)	do {} while (0)
#define check_arg_cpu(cpu)	do {} while (0)
#endif

u_int openpic_read(volatile u_int *addr)
{
	u_int val;

	val = in_le32(addr);
	return val;
}

static inline void openpic_write(volatile u_int *addr, u_int val)
{
	out_le32(addr, val);
}

static inline u_int openpic_readfield(volatile u_int *addr, u_int mask)
{
	u_int val = openpic_read(addr);
	return val & mask;
}

inline void openpic_writefield(volatile u_int *addr, u_int mask,
			       u_int field)
{
	u_int val = openpic_read(addr);
	openpic_write(addr, (val & ~mask) | (field & mask));
}

static inline void openpic_clearfield(volatile u_int *addr, u_int mask)
{
	openpic_writefield(addr, mask, 0);
}

static inline void openpic_setfield(volatile u_int *addr, u_int mask)
{
	openpic_writefield(addr, mask, mask);
}

static void openpic_safe_writefield(volatile u_int *addr, u_int mask,
				    u_int field)
{
	openpic_setfield(addr, OPENPIC_MASK);
	while (openpic_read(addr) & OPENPIC_ACTIVITY);
	openpic_writefield(addr, mask | OPENPIC_MASK, field | OPENPIC_MASK);
}

#ifdef CONFIG_SMP
/* yes this is right ... bug, feature, you decide! -- tgall */
u_int openpic_read_IPI(volatile u_int* addr)
{
         u_int val = 0;
#ifdef CONFIG_POWER3
        val = in_be32(addr);
#else
        val = in_le32(addr);
#endif
        return val;
}

/* because of the power3 be / le above, this is needed */
inline void openpic_writefield_IPI(volatile u_int* addr, u_int mask, u_int field)
{
        u_int  val = openpic_read_IPI(addr);
        openpic_write(addr, (val & ~mask) | (field & mask));
}

static inline void openpic_clearfield_IPI(volatile u_int *addr, u_int mask)
{
        openpic_writefield_IPI(addr, mask, 0);
}

static inline void openpic_setfield_IPI(volatile u_int *addr, u_int mask)
{
        openpic_writefield_IPI(addr, mask, mask);
}

static void openpic_safe_writefield_IPI(volatile u_int *addr, u_int mask, u_int field)
{
        openpic_setfield_IPI(addr, OPENPIC_MASK);

        /* wait until it's not in use */
        /* BenH: Is this code really enough ? I would rather check the result
         *       and eventually retry ...
         */
        while(openpic_read_IPI(addr) & OPENPIC_ACTIVITY);

        openpic_writefield_IPI(addr, mask | OPENPIC_MASK, field | OPENPIC_MASK);
}
#endif /* CONFIG_SMP */

#ifdef CONFIG_EPIC_SERIAL_MODE
static void __init openpic_eicr_set_clk(u_int clkval)
{
	openpic_writefield(&OpenPIC->Global.Global_Configuration1,
			OPENPIC_EICR_S_CLK_MASK, (clkval << 28));
}

static void __init openpic_enable_sie(void)
{
	openpic_setfield(&OpenPIC->Global.Global_Configuration1,
			OPENPIC_EICR_SIE);
}
#endif

#if defined(CONFIG_EPIC_SERIAL_MODE) || defined(CONFIG_PMAC_PBOOK)
static void openpic_reset(void)
{
	openpic_setfield(&OpenPIC->Global.Global_Configuration0,
			 OPENPIC_CONFIG_RESET);
	while (openpic_readfield(&OpenPIC->Global.Global_Configuration0,
				 OPENPIC_CONFIG_RESET))
		mb();
}
#endif

void __init openpic_set_sources(int first_irq, int num_irqs, void *first_ISR)
{
	volatile OpenPIC_Source *src = first_ISR;
	int i, last_irq;

	last_irq = first_irq + num_irqs;
	if (last_irq > NumSources)
		NumSources = last_irq;
	if (src == 0)
		src = &((struct OpenPIC *)OpenPIC_Addr)->Source[first_irq];
	for (i = first_irq; i < last_irq; ++i, ++src)
		ISR[i] = src;
}

/*
 * The `offset' parameter defines where the interrupts handled by the
 * OpenPIC start in the space of interrupt numbers that the kernel knows
 * about.  In other words, the OpenPIC's IRQ0 is numbered `offset' in the
 * kernel's interrupt numbering scheme.
 * We assume there is only one OpenPIC.
 */
void __init openpic_init(int offset)
{
	u_int t, i;
	u_int timerfreq;
	const char *version;

	if (!OpenPIC_Addr) {
		printk("No OpenPIC found !\n");
		return;
	}
	OpenPIC = (volatile struct OpenPIC *)OpenPIC_Addr;

#ifdef CONFIG_EPIC_SERIAL_MODE
	/* Have to start from ground zero.
	*/
	openpic_reset();
#endif

	if (ppc_md.progress) ppc_md.progress("openpic: enter", 0x122);

	t = openpic_read(&OpenPIC->Global.Feature_Reporting0);
	switch (t & OPENPIC_FEATURE_VERSION_MASK) {
	case 1:
		version = "1.0";
		break;
	case 2:
		version = "1.2";
		break;
	case 3:
		version = "1.3";
		break;
	default:
		version = "?";
		break;
	}
	NumProcessors = ((t & OPENPIC_FEATURE_LAST_PROCESSOR_MASK) >>
			 OPENPIC_FEATURE_LAST_PROCESSOR_SHIFT) + 1;
	if (NumSources == 0)
		openpic_set_sources(0,
				    ((t & OPENPIC_FEATURE_LAST_SOURCE_MASK) >>
				     OPENPIC_FEATURE_LAST_SOURCE_SHIFT) + 1,
				    NULL);
	printk("OpenPIC Version %s (%d CPUs and %d IRQ sources) at %p\n",
	       version, NumProcessors, NumSources, OpenPIC);
	timerfreq = openpic_read(&OpenPIC->Global.Timer_Frequency);
	if (timerfreq)
		printk("OpenPIC timer frequency is %d.%06d MHz\n",
		       timerfreq / 1000000, timerfreq % 1000000);

	open_pic_irq_offset = offset;

	/* Initialize timer interrupts */
	if ( ppc_md.progress ) ppc_md.progress("openpic: timer",0x3ba);
	for (i = 0; i < OPENPIC_NUM_TIMERS; i++) {
		/* Disabled, Priority 0 */
		openpic_inittimer(i, 0, OPENPIC_VEC_TIMER+i+offset);
		/* No processor */
		openpic_maptimer(i, 0);
	}

#ifdef CONFIG_SMP
	/* Initialize IPI interrupts */
	if ( ppc_md.progress ) ppc_md.progress("openpic: ipi",0x3bb);
	for (i = 0; i < OPENPIC_NUM_IPI; i++) {
		/* Disabled, Priority 10..13 */
		openpic_initipi(i, 10+i, OPENPIC_VEC_IPI+i+offset);
		/* IPIs are per-CPU */
		irq_desc[OPENPIC_VEC_IPI+i+offset].status |= IRQ_PER_CPU;
		irq_desc[OPENPIC_VEC_IPI+i+offset].handler = &open_pic_ipi;
	}
#endif

	/* Initialize external interrupts */
	if (ppc_md.progress) ppc_md.progress("openpic: external",0x3bc);

	openpic_set_priority(0xf);

	/* Init all external sources, including possibly the cascade. */
	for (i = 0; i < NumSources; i++) {
		int sense;

		if (ISR[i] == 0)
			continue;

		/* the bootloader may have left it enabled (bad !) */
		openpic_disable_irq(i+offset);

		sense = (i < OpenPIC_NumInitSenses)? OpenPIC_InitSenses[i]: \
				(IRQ_SENSE_LEVEL | IRQ_POLARITY_NEGATIVE);

		if (sense & IRQ_SENSE_MASK)
			irq_desc[i+offset].status = IRQ_LEVEL;

		/* Enabled, Priority 8 */
		openpic_initirq(i, 8, i+offset, (sense & IRQ_POLARITY_MASK),
				(sense & IRQ_SENSE_MASK));
		/* Processor 0 */
		openpic_mapirq(i, 1<<0, 0);
	}

	/* Init descriptors */
	for (i = offset; i < NumSources + offset; i++)
		irq_desc[i].handler = &open_pic;

	/* Initialize the spurious interrupt */
	if (ppc_md.progress) ppc_md.progress("openpic: spurious",0x3bd);
	openpic_set_spurious(OPENPIC_VEC_SPURIOUS+offset);

	openpic_disable_8259_pass_through();
#ifdef CONFIG_EPIC_SERIAL_MODE
	openpic_eicr_set_clk(7);	/* Slowest value until we know better */
	openpic_enable_sie();
#endif
	openpic_set_priority(0);

	if (ppc_md.progress) ppc_md.progress("openpic: exit",0x222);
}

#ifdef notused
static void openpic_enable_8259_pass_through(void)
{
	openpic_clearfield(&OpenPIC->Global.Global_Configuration0,
			   OPENPIC_CONFIG_8259_PASSTHROUGH_DISABLE);
}
#endif /* notused */

/* This can't be __init, it is used in openpic_sleep_restore_intrs */
static void openpic_disable_8259_pass_through(void)
{
	openpic_setfield(&OpenPIC->Global.Global_Configuration0,
			 OPENPIC_CONFIG_8259_PASSTHROUGH_DISABLE);
}

/*
 *  Find out the current interrupt
 */
u_int openpic_irq(void)
{
	u_int vec;
	DECL_THIS_CPU;

	CHECK_THIS_CPU;
	vec = openpic_readfield(&OpenPIC->THIS_CPU.Interrupt_Acknowledge,
				OPENPIC_VECTOR_MASK);
	return vec;
}

void openpic_eoi(void)
{
	DECL_THIS_CPU;

	CHECK_THIS_CPU;
	openpic_write(&OpenPIC->THIS_CPU.EOI, 0);
	/* Handle PCI write posting */
	(void)openpic_read(&OpenPIC->THIS_CPU.EOI);
}

#ifdef notused
static u_int openpic_get_priority(void)
{
	DECL_THIS_CPU;

	CHECK_THIS_CPU;
	return openpic_readfield(&OpenPIC->THIS_CPU.Current_Task_Priority,
				 OPENPIC_CURRENT_TASK_PRIORITY_MASK);