pci_link.c

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/*
 *  pci_link.c - ACPI PCI Interrupt Link Device Driver ($Revision: 34 $)
 *
 *  Copyright (C) 2001, 2002 Andy Grover <[e-mail]>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <[e-mail]>
 *  Copyright (C) 2002       Dominik Brodowski <[e-mail]>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or (at
 *  your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * TBD: 
 *      1. Support more than one IRQ resource entry per link device (index).
 *	2. Implement start/stop mechanism and use ACPI Bus Driver facilities
 *	   for IRQ management (e.g. start()->_SRS).
 */

#include <linux/sysdev.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/proc_fs.h>
#include <linux/spinlock.h>
#include <linux/pm.h>
#include <linux/pci.h>
#include <linux/mutex.h>

#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>

#define _COMPONENT		ACPI_PCI_COMPONENT
ACPI_MODULE_NAME("pci_link");
#define ACPI_PCI_LINK_CLASS		"pci_irq_routing"
#define ACPI_PCI_LINK_DEVICE_NAME	"PCI Interrupt Link"
#define ACPI_PCI_LINK_FILE_INFO		"info"
#define ACPI_PCI_LINK_FILE_STATUS	"state"
#define ACPI_PCI_LINK_MAX_POSSIBLE 16
static int acpi_pci_link_add(struct acpi_device *device);
static int acpi_pci_link_remove(struct acpi_device *device, int type);

static struct acpi_device_id link_device_ids[] = {
	{"PNP0C0F", 0},
	{"", 0},
};
MODULE_DEVICE_TABLE(acpi, link_device_ids);

static struct acpi_driver acpi_pci_link_driver = {
	.name = "pci_link",
	.class = ACPI_PCI_LINK_CLASS,
	.ids = link_device_ids,
	.ops = {
		.add = acpi_pci_link_add,
		.remove = acpi_pci_link_remove,
		},
};

/*
 * If a link is initialized, we never change its active and initialized
 * later even the link is disable. Instead, we just repick the active irq
 */
struct acpi_pci_link_irq {
	u8 active;		/* Current IRQ */
	u8 triggering;		/* All IRQs */
	u8 polarity;	/* All IRQs */
	u8 resource_type;
	u8 possible_count;
	u8 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
	u8 initialized:1;
	u8 reserved:7;
};

struct acpi_pci_link {
	struct list_head node;
	struct acpi_device *device;
	struct acpi_pci_link_irq irq;
	int refcnt;
};

static struct {
	int count;
	struct list_head entries;
} acpi_link;
DEFINE_MUTEX(acpi_link_lock);

/* --------------------------------------------------------------------------
                            PCI Link Device Management
   -------------------------------------------------------------------------- */

/*
 * set context (link) possible list from resource list
 */
static acpi_status
acpi_pci_link_check_possible(struct acpi_resource *resource, void *context)
{
	struct acpi_pci_link *link = context;
	u32 i = 0;


	switch (resource->type) {
	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
		return AE_OK;
	case ACPI_RESOURCE_TYPE_IRQ:
		{
			struct acpi_resource_irq *p = &resource->data.irq;
			if (!p || !p->interrupt_count) {
				printk(KERN_WARNING PREFIX "Blank IRQ resource\n");
				return AE_OK;
			}
			for (i = 0;
			     (i < p->interrupt_count
			      && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
				if (!p->interrupts[i]) {
					printk(KERN_WARNING PREFIX "Invalid IRQ %d\n",
						      p->interrupts[i]);
					continue;
				}
				link->irq.possible[i] = p->interrupts[i];
				link->irq.possible_count++;
			}
			link->irq.triggering = p->triggering;
			link->irq.polarity = p->polarity;
			link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
			break;
		}
	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
		{
			struct acpi_resource_extended_irq *p =
			    &resource->data.extended_irq;
			if (!p || !p->interrupt_count) {
				printk(KERN_WARNING PREFIX
					      "Blank EXT IRQ resource\n");
				return AE_OK;
			}
			for (i = 0;
			     (i < p->interrupt_count
			      && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
				if (!p->interrupts[i]) {
					printk(KERN_WARNING PREFIX "Invalid IRQ %d\n",
						      p->interrupts[i]);
					continue;
				}
				link->irq.possible[i] = p->interrupts[i];
				link->irq.possible_count++;
			}
			link->irq.triggering = p->triggering;
			link->irq.polarity = p->polarity;
			link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
			break;
		}
	default:
		printk(KERN_ERR PREFIX "Resource is not an IRQ entry\n");
		return AE_OK;
	}

	return AE_CTRL_TERMINATE;
}

static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
{
	acpi_status status;


	if (!link)
		return -EINVAL;

	status = acpi_walk_resources(link->device->handle, METHOD_NAME__PRS,
				     acpi_pci_link_check_possible, link);
	if (ACPI_FAILURE(status)) {
		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRS"));
		return -ENODEV;
	}

	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
			  "Found %d possible IRQs\n",
			  link->irq.possible_count));

	return 0;
}

static acpi_status
acpi_pci_link_check_current(struct acpi_resource *resource, void *context)
{
	int *irq = (int *)context;


	switch (resource->type) {
	case ACPI_RESOURCE_TYPE_IRQ:
		{
			struct acpi_resource_irq *p = &resource->data.irq;
			if (!p || !p->interrupt_count) {
				/*
				 * IRQ descriptors may have no IRQ# bits set,
				 * particularly those those w/ _STA disabled
				 */
				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
						  "Blank IRQ resource\n"));
				return AE_OK;
			}
			*irq = p->interrupts[0];
			break;
		}
	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
		{
			struct acpi_resource_extended_irq *p =
			    &resource->data.extended_irq;
			if (!p || !p->interrupt_count) {
				/*
				 * extended IRQ descriptors must
				 * return at least 1 IRQ
				 */
				printk(KERN_WARNING PREFIX
					      "Blank EXT IRQ resource\n");
				return AE_OK;
			}
			*irq = p->interrupts[0];
			break;
		}
		break;
	default:
		printk(KERN_ERR PREFIX "Resource %d isn't an IRQ\n", resource->type);
	case ACPI_RESOURCE_TYPE_END_TAG:
		return AE_OK;
	}
	return AE_CTRL_TERMINATE;
}

/*
 * Run _CRS and set link->irq.active
 *
 * return value:
 * 0 - success
 * !0 - failure
 */
static int acpi_pci_link_get_current(struct acpi_pci_link *link)
{
	int result = 0;
	acpi_status status = AE_OK;
	int irq = 0;

	if (!link)
		return -EINVAL;

	link->irq.active = 0;

	/* in practice, status disabled is meaningless, ignore it */
	if (acpi_strict) {
		/* Query _STA, set link->device->status */
		result = acpi_bus_get_status(link->device);
		if (result) {
			printk(KERN_ERR PREFIX "Unable to read status\n");
			goto end;
		}

		if (!link->device->status.enabled) {
			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link disabled\n"));
			return 0;
		}
	}

	/* 
	 * Query and parse _CRS to get the current IRQ assignment. 
	 */

	status = acpi_walk_resources(link->device->handle, METHOD_NAME__CRS,
				     acpi_pci_link_check_current, &irq);
	if (ACPI_FAILURE(status)) {
		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _CRS"));
		result = -ENODEV;
		goto end;
	}

	if (acpi_strict && !irq) {
		printk(KERN_ERR PREFIX "_CRS returned 0\n");
		result = -ENODEV;
	}

	link->irq.active = irq;

	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link at IRQ %d \n", link->irq.active));

      end:
	return result;
}

static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
{
	int result = 0;
	acpi_status status = AE_OK;
	struct {
		struct acpi_resource res;
		struct acpi_resource end;
	} *resource;
	struct acpi_buffer buffer = { 0, NULL };


	if (!link || !irq)
		return -EINVAL;

	resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
	if (!resource)
		return -ENOMEM;

	buffer.length = sizeof(*resource) + 1;
	buffer.pointer = resource;

	switch (link->irq.resource_type) {
	case ACPI_RESOURCE_TYPE_IRQ:
		resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
		resource->res.length = sizeof(struct acpi_resource);
		resource->res.data.irq.triggering = link->irq.triggering;
		resource->res.data.irq.polarity =
		    link->irq.polarity;
		if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
			resource->res.data.irq.sharable =
			    ACPI_EXCLUSIVE;
		else
			resource->res.data.irq.sharable = ACPI_SHARED;
		resource->res.data.irq.interrupt_count = 1;
		resource->res.data.irq.interrupts[0] = irq;
		break;

	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
		resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
		resource->res.length = sizeof(struct acpi_resource);
		resource->res.data.extended_irq.producer_consumer =
		    ACPI_CONSUMER;
		resource->res.data.extended_irq.triggering =
		    link->irq.triggering;
		resource->res.data.extended_irq.polarity =
		    link->irq.polarity;
		if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
			resource->res.data.irq.sharable =
			    ACPI_EXCLUSIVE;
		else
			resource->res.data.irq.sharable = ACPI_SHARED;
		resource->res.data.extended_irq.interrupt_count = 1;
		resource->res.data.extended_irq.interrupts[0] = irq;
		/* ignore resource_source, it's optional */
		break;
	default:
		printk(KERN_ERR PREFIX "Invalid Resource_type %d\n", link->irq.resource_type);
		result = -EINVAL;
		goto end;

	}
	resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;

	/* Attempt to set the resource */
	status = acpi_set_current_resources(link->device->handle, &buffer);

	/* check for total failure */
	if (ACPI_FAILURE(status)) {
		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SRS"));
		result = -ENODEV;
		goto end;
	}

	/* Query _STA, set device->status */
	result = acpi_bus_get_status(link->device);
	if (result) {
		printk(KERN_ERR PREFIX "Unable to read status\n");
		goto end;
	}
	if (!link->device->status.enabled) {
		printk(KERN_WARNING PREFIX
			      "%s [%s] disabled and referenced, BIOS bug\n",
			      acpi_device_name(link->device),
			      acpi_device_bid(link->device));
	}

	/* Query _CRS, set link->irq.active */
	result = acpi_pci_link_get_current(link);
	if (result) {
		goto end;
	}

	/*
	 * Is current setting not what we set?
	 * set link->irq.active
	 */
	if (link->irq.active != irq) {
		/*
		 * policy: when _CRS doesn't return what we just _SRS
		 * assume _SRS worked and override _CRS value.
		 */
		printk(KERN_WARNING PREFIX
			      "%s [%s] BIOS reported IRQ %d, using IRQ %d\n",
			      acpi_device_name(link->device),
			      acpi_device_bid(link->device), link->irq.active, irq);
		link->irq.active = irq;
	}

	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Set IRQ %d\n", link->irq.active));

      end:
	kfree(resource);
	return result;
}

/* --------------------------------------------------------------------------
                            PCI Link IRQ Management
   -------------------------------------------------------------------------- */

/*
 * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
 * Link Devices to move the PIRQs around to minimize sharing.
 * 
 * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
 * that the BIOS has already set to active.  This is necessary because
 * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
 * if the BIOS doesn't set a Link Device active, ACPI needs to program it
 * even if acpi_irq_nobalance is set.
 *
 * A tables of penalties avoids directing PCI interrupts to well known
 * ISA IRQs. Boot params are available to over-ride the default table:
 *
 * List interrupts that are free for PCI use.
 * acpi_irq_pci=n[,m]
 *
 * List interrupts that should not be used for PCI:
 * acpi_irq_isa=n[,m]
 *
 * Note that PCI IRQ routers have a list of possible IRQs,
 * which may not include the IRQs this table says are available.
 * 
 * Since this heuristic can't tell the difference between a link
 * that no device will attach to, vs. a link which may be shared
 * by multiple active devices -- it is not optimal.
 *
 * If interrupt performance is that important, get an IO-APIC system
 * with a pin dedicated to each device.  Or for that matter, an MSI
 * enabled system.
 */

#define ACPI_MAX_IRQS		256
#define ACPI_MAX_ISA_IRQ	16

#define PIRQ_PENALTY_PCI_AVAILABLE	(0)
#define PIRQ_PENALTY_PCI_POSSIBLE	(16*16)
#define PIRQ_PENALTY_PCI_USING		(16*16*16)
#define PIRQ_PENALTY_ISA_TYPICAL	(16*16*16*16)
#define PIRQ_PENALTY_ISA_USED		(16*16*16*16*16)
#define PIRQ_PENALTY_ISA_ALWAYS		(16*16*16*16*16*16)

static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ0 timer */
	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ1 keyboard */
	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ2 cascade */
	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ3 serial */
	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ4 serial */
	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ5 sometimes SoundBlaster */
	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ6 */
	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ7 parallel, spurious */
	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ8 rtc, sometimes */
	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ9  PCI, often acpi */
	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ10 PCI */
	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ11 PCI */
	PIRQ_PENALTY_ISA_USED,	/* IRQ12 mouse */
	PIRQ_PENALTY_ISA_USED,	/* IRQ13 fpe, sometimes */
	PIRQ_PENALTY_ISA_USED,	/* IRQ14 ide0 */
	PIRQ_PENALTY_ISA_USED,	/* IRQ15 ide1 */
	/* >IRQ15 */
};