pci_link.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 874 行 · 第 1/2 页

/*
 *  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 <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_HID		"PNP0C0F"
#define ACPI_PCI_LINK_DRIVER_NAME	"ACPI PCI Interrupt Link Driver"
#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_driver acpi_pci_link_driver = {
	.name =		ACPI_PCI_LINK_DRIVER_NAME,
	.class =	ACPI_PCI_LINK_CLASS,
	.ids =		ACPI_PCI_LINK_HID,
	.ops =		{
				.add =    acpi_pci_link_add,
				.remove = acpi_pci_link_remove,
			},
};

struct acpi_pci_link_irq {
	u8			active;			/* Current IRQ */
	u8			edge_level;		/* All IRQs */
	u8			active_high_low;	/* All IRQs */
	u8			initialized;
	u8			resource_type;
	u8			possible_count;
	u8			possible[ACPI_PCI_LINK_MAX_POSSIBLE];
};

struct acpi_pci_link {
	struct list_head	node;
	struct acpi_device	*device;
	acpi_handle		handle;
	struct acpi_pci_link_irq irq;
};

static struct {
	int			count;
	struct list_head	entries;
}				acpi_link;


/* --------------------------------------------------------------------------
                            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 = (struct acpi_pci_link *) context;
	u32			i = 0;

	ACPI_FUNCTION_TRACE("acpi_pci_link_check_possible");

	switch (resource->id) {
	case ACPI_RSTYPE_START_DPF:
		return AE_OK;
	case ACPI_RSTYPE_IRQ:
	{
		struct acpi_resource_irq *p = &resource->data.irq;
		if (!p || !p->number_of_interrupts) {
			ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Blank IRQ resource\n"));
			return AE_OK;
		}
		for (i = 0; (i<p->number_of_interrupts && i<ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
			if (!p->interrupts[i]) {
				ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Invalid IRQ %d\n", p->interrupts[i]));
				continue;
			}
			link->irq.possible[i] = p->interrupts[i];
			link->irq.possible_count++;
		}
		link->irq.edge_level = p->edge_level;
		link->irq.active_high_low = p->active_high_low;
		link->irq.resource_type = ACPI_RSTYPE_IRQ;
		break;
	}
	case ACPI_RSTYPE_EXT_IRQ:
	{
		struct acpi_resource_ext_irq *p = &resource->data.extended_irq;
		if (!p || !p->number_of_interrupts) {
			ACPI_DEBUG_PRINT((ACPI_DB_WARN, 
				"Blank EXT IRQ resource\n"));
			return AE_OK;
		}
		for (i = 0; (i<p->number_of_interrupts && i<ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
			if (!p->interrupts[i]) {
				ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Invalid IRQ %d\n", p->interrupts[i]));
				continue;
			}
			link->irq.possible[i] = p->interrupts[i];
			link->irq.possible_count++;
		}
		link->irq.edge_level = p->edge_level;
		link->irq.active_high_low = p->active_high_low;
		link->irq.resource_type = ACPI_RSTYPE_EXT_IRQ;
		break;
	}
	default:
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, 
			"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;

	ACPI_FUNCTION_TRACE("acpi_pci_link_get_possible");

	if (!link)
		return_VALUE(-EINVAL);

	status = acpi_walk_resources(link->handle, METHOD_NAME__PRS,
			acpi_pci_link_check_possible, link);
	if (ACPI_FAILURE(status)) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _PRS\n"));
		return_VALUE(-ENODEV);
	}

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

	return_VALUE(0);
}


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

	ACPI_FUNCTION_TRACE("acpi_pci_link_check_current");

	switch (resource->id) {
	case ACPI_RSTYPE_IRQ:
	{
		struct acpi_resource_irq *p = &resource->data.irq;
		if (!p || !p->number_of_interrupts) {
			/*
			 * 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_RSTYPE_EXT_IRQ:
	{
		struct acpi_resource_ext_irq *p = &resource->data.extended_irq;
		if (!p || !p->number_of_interrupts) {
			/*
			 * extended IRQ descriptors must
			 * return at least 1 IRQ
			 */
			ACPI_DEBUG_PRINT((ACPI_DB_WARN,
				"Blank EXT IRQ resource\n"));
			return AE_OK;
		}
		*irq = p->interrupts[0];
		break;
	}
	default:
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
			"Resource isn't an IRQ\n"));
		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;

	ACPI_FUNCTION_TRACE("acpi_pci_link_get_current");

	if (!link || !link->handle)
		return_VALUE(-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) {
			ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Unable to read status\n"));
			goto end;
		}

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

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

	status = acpi_walk_resources(link->handle, METHOD_NAME__CRS,
			acpi_pci_link_check_current, &irq);
	if (ACPI_FAILURE(status)) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _CRS\n"));
		result = -ENODEV;
		goto end;
	}

	if (acpi_strict && !irq) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "_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_VALUE(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 = {sizeof(resource)+1, &resource};

	ACPI_FUNCTION_TRACE("acpi_pci_link_set");

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

	memset(&resource, 0, sizeof(resource));

	switch(link->irq.resource_type) {
	case ACPI_RSTYPE_IRQ:
		resource.res.id = ACPI_RSTYPE_IRQ;
		resource.res.length = sizeof(struct acpi_resource);
		resource.res.data.irq.edge_level = link->irq.edge_level;
		resource.res.data.irq.active_high_low = link->irq.active_high_low;
		if (link->irq.edge_level == ACPI_EDGE_SENSITIVE)
			resource.res.data.irq.shared_exclusive = ACPI_EXCLUSIVE;
		else
			resource.res.data.irq.shared_exclusive = ACPI_SHARED;
		resource.res.data.irq.number_of_interrupts = 1;
		resource.res.data.irq.interrupts[0] = irq;
		break;
	   
	case ACPI_RSTYPE_EXT_IRQ:
		resource.res.id = ACPI_RSTYPE_EXT_IRQ;
		resource.res.length = sizeof(struct acpi_resource);
		resource.res.data.extended_irq.producer_consumer = ACPI_CONSUMER;
		resource.res.data.extended_irq.edge_level = link->irq.edge_level;
		resource.res.data.extended_irq.active_high_low = link->irq.active_high_low;
		if (link->irq.edge_level == ACPI_EDGE_SENSITIVE)
			resource.res.data.irq.shared_exclusive = ACPI_EXCLUSIVE;
		else
			resource.res.data.irq.shared_exclusive = ACPI_SHARED;
		resource.res.data.extended_irq.number_of_interrupts = 1;
		resource.res.data.extended_irq.interrupts[0] = irq;
		/* ignore resource_source, it's optional */
		break;
	default:
		printk("ACPI BUG: resource_type %d\n", link->irq.resource_type);
		return_VALUE(-EINVAL);

	}
	resource.end.id = ACPI_RSTYPE_END_TAG;

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

	/* check for total failure */
	if (ACPI_FAILURE(status)) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _SRS\n"));
		return_VALUE(-ENODEV);
	}

	/* Query _STA, set device->status */
	result = acpi_bus_get_status(link->device);
	if (result) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Unable to read status\n"));
		return_VALUE(result);
	}
	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) {
		return_VALUE(result);
	}

	/*
	 * 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));
	
	return_VALUE(0);
}


/* --------------------------------------------------------------------------
                            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