iosapic.c

一个2.4.21版本的嵌入式linux内核

/*
 * I/O SAPIC support.
 *
 * Copyright (C) 1999 Intel Corp.
 * Copyright (C) 1999 Asit Mallick <[e-mail]>
 * Copyright (C) 2000-2002 J.I. Lee <[e-mail]>
 * Copyright (C) 1999-2000, 2002 Hewlett-Packard Co.
 *	David Mosberger-Tang <[e-mail]>
 * Copyright (C) 1999 VA Linux Systems
 * Copyright (C) 1999,2000 Walt Drummond <[e-mail]>
 *
 * 00/04/19	D. Mosberger	Rewritten to mirror more closely the x86 I/O APIC code.
 *				In particular, we now have separate handlers for edge
 *				and level triggered interrupts.
 * 00/10/27	Asit Mallick, Goutham Rao <[e-mail]> IRQ vector allocation
 *				PCI to vector mapping, shared PCI interrupts.
 * 00/10/27	D. Mosberger	Document things a bit more to make them more understandable.
 *				Clean up much of the old IOSAPIC cruft.
 * 01/07/27	J.I. Lee	PCI irq routing, Platform/Legacy interrupts and fixes for
 *				ACPI S5(SoftOff) support.
 * 02/01/23	J.I. Lee	iosapic pgm fixes for PCI irq routing from _PRT
 * 02/01/07     E. Focht        <[e-mail]> Redirectable interrupt vectors in
 *                              iosapic_set_affinity(), initializations for
 *                              /proc/irq/#/smp_affinity
 * 02/04/02	P. Diefenbaugh	Cleaned up ACPI PCI IRQ routing.
 * 02/04/18	J.I. Lee	bug fix in iosapic_init_pci_irq
 * 02/04/30	J.I. Lee	bug fix in find_iosapic to fix ACPI PCI IRQ to IOSAPIC mapping error
 * 02/07/29	T. Kochi	Allocate interrupt vectors dynamically
 * 02/08/04	T. Kochi	Cleaned up terminology (irq, global system interrupt, vector, etc.)
 * 02/08/13	B. Helgaas	Support PCI segments
 */
/*
 * Here is what the interrupt logic between a PCI device and the CPU looks like:
 *
 * (1) A PCI device raises one of the four interrupt pins (INTA, INTB, INTC, INTD).  The
 *     device is uniquely identified by its segment--, bus--, and slot-number (the function
 *     number does not matter here because all functions share the same interrupt
 *     lines).
 *
 * (2) The motherboard routes the interrupt line to a pin on a IOSAPIC controller.
 *     Multiple interrupt lines may have to share the same IOSAPIC pin (if they're level
 *     triggered and use the same polarity).  Each interrupt line has a unique Global
 *     System Interrupt (GSI) number which can be calculated as the sum of the controller's
 *     base GSI number and the IOSAPIC pin number to which the line connects.
 *
 * (3) The IOSAPIC uses internal routing table entries (RTEs) to map the IOSAPIC pin
 *     to the IA-64 interrupt vector.  This interrupt vector is then sent to the CPU.
 *
 * (4) The kernel recognizes an interrupt as an IRQ.  The IRQ interface
 *     is an architecture-independent interrupt handling mechanism in
 *     Linux.  An IRQ is a number, so we need a mapping between IRQ
 *     numbers and IA-64 vectors.  The platform_irq_to_vector(irq) and
 *     platform_local_vector_to_irq(vector) APIs can define platform-
 *     specific mappings.
 *
 * To sum up, there are three levels of mappings involved:
 *
 *	PCI pin -> global system interrupt (GSI) -> IA-64 vector <-> IRQ
 *
 * Note: The term "IRQ" is loosely used everywhere in the Linux kernel
 * to describe interrupts.  In this module, "IRQ" refers only to Linux
 * IRQ numbers ("isa_irq" is an exception to this rule).
 */
#include <linux/config.h>

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/string.h>
#include <linux/irq.h>
#include <linux/acpi.h>

#include <asm/delay.h>
#include <asm/hw_irq.h>
#include <asm/io.h>
#include <asm/iosapic.h>
#include <asm/machvec.h>
#include <asm/processor.h>
#include <asm/ptrace.h>
#include <asm/system.h>


#undef DEBUG_INTERRUPT_ROUTING
#undef OVERRIDE_DEBUG

#ifdef DEBUG_INTERRUPT_ROUTING
#define DBG(fmt...)	printk(fmt)
#else
#define DBG(fmt...)
#endif

static spinlock_t iosapic_lock = SPIN_LOCK_UNLOCKED;

/* PCI pin to GSI routing information.  This info typically comes from ACPI. */

static struct {
	int num_routes;
	struct pci_vector_struct *route;
} pci_irq;

/* These tables map IA-64 vectors to the IOSAPIC pin that generates this vector. */

static struct iosapic_intr_info {
	char		*addr;		/* base address of IOSAPIC */
	unsigned int	gsi_base;	/* first GSI assigned to this IOSAPIC */
	char		rte_index;	/* IOSAPIC RTE index (-1 => not an IOSAPIC interrupt) */
	unsigned char	dmode	: 3;	/* delivery mode (see iosapic.h) */
	unsigned char 	polarity: 1;	/* interrupt polarity (see iosapic.h) */
	unsigned char	trigger	: 1;	/* trigger mode (see iosapic.h) */
} iosapic_intr_info[IA64_NUM_VECTORS];

static struct iosapic {
	char		*addr;		/* base address of IOSAPIC */
	unsigned int 	gsi_base;	/* first GSI assigned to this IOSAPIC */
	unsigned short 	num_rte;	/* number of RTE in this IOSAPIC */
	unsigned char	pcat_compat;	/* 8259 compatibility flag */
} iosapic_lists[256] __devinitdata;

static int __devinitdata num_iosapic = 0;


/*
 * Find an IOSAPIC associated with a GSI
 */
static inline int __devinit
find_iosapic (unsigned int gsi)
{
	int i;

	for (i = 0; i < num_iosapic; i++)
		if ((unsigned) (gsi - iosapic_lists[i].gsi_base) < iosapic_lists[i].num_rte)
			return i;
	return -1;
}

/*
 * Translate GSI number to the corresponding IA-64 interrupt vector.  If no
 * entry exists, return -1.
 */
int
gsi_to_vector (unsigned int gsi)
{
	int vector;

	for (vector = 0; vector < IA64_NUM_VECTORS; vector++)
		if (iosapic_intr_info[vector].gsi_base + iosapic_intr_info[vector].rte_index == gsi)
			return vector;
	return -1;
}

static void
set_rte (unsigned int vector, unsigned int dest)
{
	unsigned long pol, trigger, dmode;
	u32 low32, high32;
	char *addr;
	int rte_index;
	char redir;

	rte_index = iosapic_intr_info[vector].rte_index;
	if (rte_index < 0)
		return;		/* not an IOSAPIC interrupt */

	addr    = iosapic_intr_info[vector].addr;
	pol     = iosapic_intr_info[vector].polarity;
	trigger = iosapic_intr_info[vector].trigger;
	dmode   = iosapic_intr_info[vector].dmode;

	redir = (dmode == IOSAPIC_LOWEST_PRIORITY) ? 1 : 0;
#ifdef CONFIG_SMP
	{
		int irq;

		for (irq = 0; irq < NR_IRQS; ++irq)
			if (irq_to_vector(irq) == vector) {
				set_irq_affinity_info(irq, (int)(dest & 0xffff), redir);
				break;
			}
	}
#endif

	low32 = ((pol << IOSAPIC_POLARITY_SHIFT) |
		 (trigger << IOSAPIC_TRIGGER_SHIFT) |
		 (dmode << IOSAPIC_DELIVERY_SHIFT) |
		 vector);

	/* dest contains both id and eid */
	high32 = (dest << IOSAPIC_DEST_SHIFT);

	writel(IOSAPIC_RTE_HIGH(rte_index), addr + IOSAPIC_REG_SELECT);
	writel(high32, addr + IOSAPIC_WINDOW);
	writel(IOSAPIC_RTE_LOW(rte_index), addr + IOSAPIC_REG_SELECT);
	writel(low32, addr + IOSAPIC_WINDOW);
}

static void
nop (unsigned int vector)
{
	/* do nothing... */
}

static void
mask_irq (unsigned int irq)
{
	unsigned long flags;
	char *addr;
	u32 low32;
	int rte_index;
	ia64_vector vec = irq_to_vector(irq);

	addr = iosapic_intr_info[vec].addr;
	rte_index = iosapic_intr_info[vec].rte_index;

	if (rte_index < 0)
		return;			/* not an IOSAPIC interrupt! */

	spin_lock_irqsave(&iosapic_lock, flags);
	{
		writel(IOSAPIC_RTE_LOW(rte_index), addr + IOSAPIC_REG_SELECT);
		low32 = readl(addr + IOSAPIC_WINDOW);

		low32 |= (1 << IOSAPIC_MASK_SHIFT);    /* set only the mask bit */
		writel(low32, addr + IOSAPIC_WINDOW);
	}
	spin_unlock_irqrestore(&iosapic_lock, flags);
}

static void
unmask_irq (unsigned int irq)
{
	unsigned long flags;
	char *addr;
	u32 low32;
	int rte_index;
	ia64_vector vec = irq_to_vector(irq);

	addr = iosapic_intr_info[vec].addr;
	rte_index = iosapic_intr_info[vec].rte_index;
	if (rte_index < 0)
		return;			/* not an IOSAPIC interrupt! */

	spin_lock_irqsave(&iosapic_lock, flags);
	{
		writel(IOSAPIC_RTE_LOW(rte_index), addr + IOSAPIC_REG_SELECT);
		low32 = readl(addr + IOSAPIC_WINDOW);

		low32 &= ~(1 << IOSAPIC_MASK_SHIFT);    /* clear only the mask bit */
		writel(low32, addr + IOSAPIC_WINDOW);
	}
	spin_unlock_irqrestore(&iosapic_lock, flags);
}


static void
iosapic_set_affinity (unsigned int irq, unsigned long mask)
{
#ifdef CONFIG_SMP
	unsigned long flags;
	u32 high32, low32;
	int dest, rte_index;
	char *addr;
	int redir = (irq & IA64_IRQ_REDIRECTED) ? 1 : 0;
	ia64_vector vec;

	irq &= (~IA64_IRQ_REDIRECTED);
	vec = irq_to_vector(irq);

	mask &= (1UL << smp_num_cpus) - 1;

	if (!mask || vec >= IA64_NUM_VECTORS)
		return;

	dest = cpu_physical_id(ffz(~mask));

	rte_index = iosapic_intr_info[vec].rte_index;
	addr = iosapic_intr_info[vec].addr;

	if (rte_index < 0)
		return;			/* not an IOSAPIC interrupt */

	set_irq_affinity_info(irq, dest, redir);

	/* dest contains both id and eid */
	high32 = dest << IOSAPIC_DEST_SHIFT;

	spin_lock_irqsave(&iosapic_lock, flags);
	{
		/* get current delivery mode by reading the low32 */
		writel(IOSAPIC_RTE_LOW(rte_index), addr + IOSAPIC_REG_SELECT);
		low32 = readl(addr + IOSAPIC_WINDOW);

		low32 &= ~(7 << IOSAPIC_DELIVERY_SHIFT);
		if (redir)
		        /* change delivery mode to lowest priority */
			low32 |= (IOSAPIC_LOWEST_PRIORITY << IOSAPIC_DELIVERY_SHIFT);
		else
		        /* change delivery mode to fixed */
			low32 |= (IOSAPIC_FIXED << IOSAPIC_DELIVERY_SHIFT);

		writel(IOSAPIC_RTE_HIGH(rte_index), addr + IOSAPIC_REG_SELECT);
		writel(high32, addr + IOSAPIC_WINDOW);
		writel(IOSAPIC_RTE_LOW(rte_index), addr + IOSAPIC_REG_SELECT);
		writel(low32, addr + IOSAPIC_WINDOW);
	}
	spin_unlock_irqrestore(&iosapic_lock, flags);
#endif
}

/*
 * Handlers for level-triggered interrupts.
 */

static unsigned int
iosapic_startup_level_irq (unsigned int irq)
{
	unmask_irq(irq);
	return 0;
}

static void
iosapic_end_level_irq (unsigned int irq)
{
	ia64_vector vec = irq_to_vector(irq);

	writel(vec, iosapic_intr_info[vec].addr + IOSAPIC_EOI);
}

#define iosapic_shutdown_level_irq	mask_irq
#define iosapic_enable_level_irq	unmask_irq
#define iosapic_disable_level_irq	mask_irq
#define iosapic_ack_level_irq		nop

struct hw_interrupt_type irq_type_iosapic_level = {
	typename:	"IO-SAPIC-level",
	startup:	iosapic_startup_level_irq,
	shutdown:	iosapic_shutdown_level_irq,
	enable:		iosapic_enable_level_irq,
	disable:	iosapic_disable_level_irq,
	ack:		iosapic_ack_level_irq,
	end:		iosapic_end_level_irq,
	set_affinity:	iosapic_set_affinity
};

/*
 * Handlers for edge-triggered interrupts.
 */

static unsigned int
iosapic_startup_edge_irq (unsigned int irq)
{
	unmask_irq(irq);
	/*
	 * IOSAPIC simply drops interrupts pended while the
	 * corresponding pin was masked, so we can't know if an
	 * interrupt is pending already.  Let's hope not...
	 */
	return 0;
}

static void
iosapic_ack_edge_irq (unsigned int irq)
{
	irq_desc_t *idesc = irq_desc(irq);
	/*
	 * Once we have recorded IRQ_PENDING already, we can mask the
	 * interrupt for real. This prevents IRQ storms from unhandled
	 * devices.
	 */
	if ((idesc->status & (IRQ_PENDING|IRQ_DISABLED)) == (IRQ_PENDING|IRQ_DISABLED))
		mask_irq(irq);
}

#define iosapic_enable_edge_irq		unmask_irq
#define iosapic_disable_edge_irq	nop
#define iosapic_end_edge_irq		nop

struct hw_interrupt_type irq_type_iosapic_edge = {
	typename:	"IO-SAPIC-edge",
	startup:	iosapic_startup_edge_irq,
	shutdown:	iosapic_disable_edge_irq,
	enable:		iosapic_enable_edge_irq,
	disable:	iosapic_disable_edge_irq,
	ack:		iosapic_ack_edge_irq,
	end:		iosapic_end_edge_irq,
	set_affinity:	iosapic_set_affinity
};

unsigned int
iosapic_version (char *addr)
{
	/*
	 * IOSAPIC Version Register return 32 bit structure like:
	 * {
	 *	unsigned int version   : 8;
	 *	unsigned int reserved1 : 8;
	 *	unsigned int max_redir : 8;
	 *	unsigned int reserved2 : 8;
	 * }
	 */
	writel(IOSAPIC_VERSION, addr + IOSAPIC_REG_SELECT);
	return readl(IOSAPIC_WINDOW + addr);
}

/*
 * if the given vector is already owned by other,
 *  assign a new vector for the other and make the vector available
 */
static void
iosapic_reassign_vector (int vector)
{
	int new_vector;

	if (iosapic_intr_info[vector].rte_index >= 0 || iosapic_intr_info[vector].addr
	    || iosapic_intr_info[vector].gsi_base || iosapic_intr_info[vector].dmode
	    || iosapic_intr_info[vector].polarity || iosapic_intr_info[vector].trigger)
	{
		new_vector = ia64_alloc_vector();
		printk("Reassigning Vector %d to %d\n", vector, new_vector);
		memcpy (&iosapic_intr_info[new_vector], &iosapic_intr_info[vector],
			sizeof(struct iosapic_intr_info));
		memset (&iosapic_intr_info[vector], 0, sizeof(struct iosapic_intr_info));
		iosapic_intr_info[vector].rte_index = -1;
	}
}

static void
register_intr (unsigned int gsi, int vector, unsigned char delivery,
	       unsigned long polarity, unsigned long edge_triggered,