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0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  *  pci_link.c - ACPI PCI Interrupt Link Device Driver ($Revision: 34 $)
0004  *
0005  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
0006  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
0007  *  Copyright (C) 2002       Dominik Brodowski <devel@brodo.de>
0008  *
0009  * TBD:
0010  *  1. Support more than one IRQ resource entry per link device (index).
0011  *  2. Implement start/stop mechanism and use ACPI Bus Driver facilities
0012  *     for IRQ management (e.g. start()->_SRS).
0013  */
0014 
0015 #define pr_fmt(fmt) "ACPI: PCI: " fmt
0016 
0017 #include <linux/syscore_ops.h>
0018 #include <linux/kernel.h>
0019 #include <linux/module.h>
0020 #include <linux/init.h>
0021 #include <linux/types.h>
0022 #include <linux/spinlock.h>
0023 #include <linux/pm.h>
0024 #include <linux/pci.h>
0025 #include <linux/mutex.h>
0026 #include <linux/slab.h>
0027 #include <linux/acpi.h>
0028 #include <linux/irq.h>
0029 
0030 #include "internal.h"
0031 
0032 #define ACPI_PCI_LINK_CLASS     "pci_irq_routing"
0033 #define ACPI_PCI_LINK_DEVICE_NAME   "PCI Interrupt Link"
0034 #define ACPI_PCI_LINK_MAX_POSSIBLE  16
0035 
0036 static int acpi_pci_link_add(struct acpi_device *device,
0037                  const struct acpi_device_id *not_used);
0038 static void acpi_pci_link_remove(struct acpi_device *device);
0039 
0040 static const struct acpi_device_id link_device_ids[] = {
0041     {"PNP0C0F", 0},
0042     {"", 0},
0043 };
0044 
0045 static struct acpi_scan_handler pci_link_handler = {
0046     .ids = link_device_ids,
0047     .attach = acpi_pci_link_add,
0048     .detach = acpi_pci_link_remove,
0049 };
0050 
0051 /*
0052  * If a link is initialized, we never change its active and initialized
0053  * later even the link is disable. Instead, we just repick the active irq
0054  */
0055 struct acpi_pci_link_irq {
0056     u32 active;     /* Current IRQ */
0057     u8 triggering;      /* All IRQs */
0058     u8 polarity;        /* All IRQs */
0059     u8 resource_type;
0060     u8 possible_count;
0061     u32 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
0062     u8 initialized:1;
0063     u8 reserved:7;
0064 };
0065 
0066 struct acpi_pci_link {
0067     struct list_head        list;
0068     struct acpi_device      *device;
0069     struct acpi_pci_link_irq    irq;
0070     int             refcnt;
0071 };
0072 
0073 static LIST_HEAD(acpi_link_list);
0074 static DEFINE_MUTEX(acpi_link_lock);
0075 static int sci_irq = -1, sci_penalty;
0076 
0077 /* --------------------------------------------------------------------------
0078                             PCI Link Device Management
0079    -------------------------------------------------------------------------- */
0080 
0081 /*
0082  * set context (link) possible list from resource list
0083  */
0084 static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
0085                         void *context)
0086 {
0087     struct acpi_pci_link *link = context;
0088     acpi_handle handle = link->device->handle;
0089     u32 i;
0090 
0091     switch (resource->type) {
0092     case ACPI_RESOURCE_TYPE_START_DEPENDENT:
0093     case ACPI_RESOURCE_TYPE_END_TAG:
0094         return AE_OK;
0095     case ACPI_RESOURCE_TYPE_IRQ:
0096         {
0097             struct acpi_resource_irq *p = &resource->data.irq;
0098             if (!p->interrupt_count) {
0099                 acpi_handle_debug(handle,
0100                           "Blank _PRS IRQ resource\n");
0101                 return AE_OK;
0102             }
0103             for (i = 0;
0104                  (i < p->interrupt_count
0105                   && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
0106                 if (!p->interrupts[i]) {
0107                     acpi_handle_debug(handle,
0108                               "Invalid _PRS IRQ %d\n",
0109                               p->interrupts[i]);
0110                     continue;
0111                 }
0112                 link->irq.possible[i] = p->interrupts[i];
0113                 link->irq.possible_count++;
0114             }
0115             link->irq.triggering = p->triggering;
0116             link->irq.polarity = p->polarity;
0117             link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
0118             break;
0119         }
0120     case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
0121         {
0122             struct acpi_resource_extended_irq *p =
0123                 &resource->data.extended_irq;
0124             if (!p->interrupt_count) {
0125                 acpi_handle_debug(handle,
0126                           "Blank _PRS EXT IRQ resource\n");
0127                 return AE_OK;
0128             }
0129             for (i = 0;
0130                  (i < p->interrupt_count
0131                   && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
0132                 if (!p->interrupts[i]) {
0133                     acpi_handle_debug(handle,
0134                               "Invalid _PRS IRQ %d\n",
0135                               p->interrupts[i]);
0136                     continue;
0137                 }
0138                 link->irq.possible[i] = p->interrupts[i];
0139                 link->irq.possible_count++;
0140             }
0141             link->irq.triggering = p->triggering;
0142             link->irq.polarity = p->polarity;
0143             link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
0144             break;
0145         }
0146     default:
0147         acpi_handle_debug(handle, "_PRS resource type 0x%x is not IRQ\n",
0148                   resource->type);
0149         return AE_OK;
0150     }
0151 
0152     return AE_CTRL_TERMINATE;
0153 }
0154 
0155 static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
0156 {
0157     acpi_handle handle = link->device->handle;
0158     acpi_status status;
0159 
0160     status = acpi_walk_resources(handle, METHOD_NAME__PRS,
0161                      acpi_pci_link_check_possible, link);
0162     if (ACPI_FAILURE(status)) {
0163         acpi_handle_debug(handle, "_PRS not present or invalid");
0164         return 0;
0165     }
0166 
0167     acpi_handle_debug(handle, "Found %d possible IRQs\n",
0168               link->irq.possible_count);
0169 
0170     return 0;
0171 }
0172 
0173 static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
0174                            void *context)
0175 {
0176     int *irq = context;
0177 
0178     switch (resource->type) {
0179     case ACPI_RESOURCE_TYPE_START_DEPENDENT:
0180     case ACPI_RESOURCE_TYPE_END_TAG:
0181         return AE_OK;
0182     case ACPI_RESOURCE_TYPE_IRQ:
0183         {
0184             struct acpi_resource_irq *p = &resource->data.irq;
0185             if (!p->interrupt_count) {
0186                 /*
0187                  * IRQ descriptors may have no IRQ# bits set,
0188                  * particularly those w/ _STA disabled
0189                  */
0190                 pr_debug("Blank _CRS IRQ resource\n");
0191                 return AE_OK;
0192             }
0193             *irq = p->interrupts[0];
0194             break;
0195         }
0196     case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
0197         {
0198             struct acpi_resource_extended_irq *p =
0199                 &resource->data.extended_irq;
0200             if (!p->interrupt_count) {
0201                 /*
0202                  * extended IRQ descriptors must
0203                  * return at least 1 IRQ
0204                  */
0205                 pr_debug("Blank _CRS EXT IRQ resource\n");
0206                 return AE_OK;
0207             }
0208             *irq = p->interrupts[0];
0209             break;
0210         }
0211         break;
0212     default:
0213         pr_debug("_CRS resource type 0x%x is not IRQ\n",
0214              resource->type);
0215         return AE_OK;
0216     }
0217 
0218     return AE_CTRL_TERMINATE;
0219 }
0220 
0221 /*
0222  * Run _CRS and set link->irq.active
0223  *
0224  * return value:
0225  * 0 - success
0226  * !0 - failure
0227  */
0228 static int acpi_pci_link_get_current(struct acpi_pci_link *link)
0229 {
0230     acpi_handle handle = link->device->handle;
0231     acpi_status status;
0232     int result = 0;
0233     int irq = 0;
0234 
0235     link->irq.active = 0;
0236 
0237     /* in practice, status disabled is meaningless, ignore it */
0238     if (acpi_strict) {
0239         /* Query _STA, set link->device->status */
0240         result = acpi_bus_get_status(link->device);
0241         if (result) {
0242             acpi_handle_err(handle, "Unable to read status\n");
0243             goto end;
0244         }
0245 
0246         if (!link->device->status.enabled) {
0247             acpi_handle_debug(handle, "Link disabled\n");
0248             return 0;
0249         }
0250     }
0251 
0252     /*
0253      * Query and parse _CRS to get the current IRQ assignment.
0254      */
0255 
0256     status = acpi_walk_resources(handle, METHOD_NAME__CRS,
0257                      acpi_pci_link_check_current, &irq);
0258     if (ACPI_FAILURE(status)) {
0259         acpi_evaluation_failure_warn(handle, "_CRS", status);
0260         result = -ENODEV;
0261         goto end;
0262     }
0263 
0264     if (acpi_strict && !irq) {
0265         acpi_handle_err(handle, "_CRS returned 0\n");
0266         result = -ENODEV;
0267     }
0268 
0269     link->irq.active = irq;
0270 
0271     acpi_handle_debug(handle, "Link at IRQ %d \n", link->irq.active);
0272 
0273       end:
0274     return result;
0275 }
0276 
0277 static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
0278 {
0279     struct {
0280         struct acpi_resource res;
0281         struct acpi_resource end;
0282     } *resource;
0283     struct acpi_buffer buffer = { 0, NULL };
0284     acpi_handle handle = link->device->handle;
0285     acpi_status status;
0286     int result;
0287 
0288     if (!irq)
0289         return -EINVAL;
0290 
0291     resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
0292     if (!resource)
0293         return -ENOMEM;
0294 
0295     buffer.length = sizeof(*resource) + 1;
0296     buffer.pointer = resource;
0297 
0298     switch (link->irq.resource_type) {
0299     case ACPI_RESOURCE_TYPE_IRQ:
0300         resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
0301         resource->res.length = sizeof(struct acpi_resource);
0302         resource->res.data.irq.triggering = link->irq.triggering;
0303         resource->res.data.irq.polarity =
0304             link->irq.polarity;
0305         if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
0306             resource->res.data.irq.shareable =
0307                 ACPI_EXCLUSIVE;
0308         else
0309             resource->res.data.irq.shareable = ACPI_SHARED;
0310         resource->res.data.irq.interrupt_count = 1;
0311         resource->res.data.irq.interrupts[0] = irq;
0312         break;
0313 
0314     case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
0315         resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
0316         resource->res.length = sizeof(struct acpi_resource);
0317         resource->res.data.extended_irq.producer_consumer =
0318             ACPI_CONSUMER;
0319         resource->res.data.extended_irq.triggering =
0320             link->irq.triggering;
0321         resource->res.data.extended_irq.polarity =
0322             link->irq.polarity;
0323         if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
0324             resource->res.data.extended_irq.shareable =
0325                 ACPI_EXCLUSIVE;
0326         else
0327             resource->res.data.extended_irq.shareable = ACPI_SHARED;
0328         resource->res.data.extended_irq.interrupt_count = 1;
0329         resource->res.data.extended_irq.interrupts[0] = irq;
0330         /* ignore resource_source, it's optional */
0331         break;
0332     default:
0333         acpi_handle_err(handle, "Invalid resource type %d\n",
0334                 link->irq.resource_type);
0335         result = -EINVAL;
0336         goto end;
0337 
0338     }
0339     resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
0340     resource->end.length = sizeof(struct acpi_resource);
0341 
0342     /* Attempt to set the resource */
0343     status = acpi_set_current_resources(link->device->handle, &buffer);
0344 
0345     /* check for total failure */
0346     if (ACPI_FAILURE(status)) {
0347         acpi_evaluation_failure_warn(handle, "_SRS", status);
0348         result = -ENODEV;
0349         goto end;
0350     }
0351 
0352     /* Query _STA, set device->status */
0353     result = acpi_bus_get_status(link->device);
0354     if (result) {
0355         acpi_handle_err(handle, "Unable to read status\n");
0356         goto end;
0357     }
0358     if (!link->device->status.enabled)
0359         acpi_handle_warn(handle, "Disabled and referenced, BIOS bug\n");
0360 
0361     /* Query _CRS, set link->irq.active */
0362     result = acpi_pci_link_get_current(link);
0363     if (result) {
0364         goto end;
0365     }
0366 
0367     /*
0368      * Is current setting not what we set?
0369      * set link->irq.active
0370      */
0371     if (link->irq.active != irq) {
0372         /*
0373          * policy: when _CRS doesn't return what we just _SRS
0374          * assume _SRS worked and override _CRS value.
0375          */
0376         acpi_handle_warn(handle, "BIOS reported IRQ %d, using IRQ %d\n",
0377                  link->irq.active, irq);
0378         link->irq.active = irq;
0379     }
0380 
0381     acpi_handle_debug(handle, "Set IRQ %d\n", link->irq.active);
0382 
0383       end:
0384     kfree(resource);
0385     return result;
0386 }
0387 
0388 /* --------------------------------------------------------------------------
0389                             PCI Link IRQ Management
0390    -------------------------------------------------------------------------- */
0391 
0392 /*
0393  * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
0394  * Link Devices to move the PIRQs around to minimize sharing.
0395  *
0396  * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
0397  * that the BIOS has already set to active.  This is necessary because
0398  * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
0399  * if the BIOS doesn't set a Link Device active, ACPI needs to program it
0400  * even if acpi_irq_nobalance is set.
0401  *
0402  * A tables of penalties avoids directing PCI interrupts to well known
0403  * ISA IRQs. Boot params are available to over-ride the default table:
0404  *
0405  * List interrupts that are free for PCI use.
0406  * acpi_irq_pci=n[,m]
0407  *
0408  * List interrupts that should not be used for PCI:
0409  * acpi_irq_isa=n[,m]
0410  *
0411  * Note that PCI IRQ routers have a list of possible IRQs,
0412  * which may not include the IRQs this table says are available.
0413  *
0414  * Since this heuristic can't tell the difference between a link
0415  * that no device will attach to, vs. a link which may be shared
0416  * by multiple active devices -- it is not optimal.
0417  *
0418  * If interrupt performance is that important, get an IO-APIC system
0419  * with a pin dedicated to each device.  Or for that matter, an MSI
0420  * enabled system.
0421  */
0422 
0423 #define ACPI_MAX_ISA_IRQS   16
0424 
0425 #define PIRQ_PENALTY_PCI_POSSIBLE   (16*16)
0426 #define PIRQ_PENALTY_PCI_USING      (16*16*16)
0427 #define PIRQ_PENALTY_ISA_TYPICAL    (16*16*16*16)
0428 #define PIRQ_PENALTY_ISA_USED       (16*16*16*16*16)
0429 #define PIRQ_PENALTY_ISA_ALWAYS     (16*16*16*16*16*16)
0430 
0431 static int acpi_isa_irq_penalty[ACPI_MAX_ISA_IRQS] = {
0432     PIRQ_PENALTY_ISA_ALWAYS,    /* IRQ0 timer */
0433     PIRQ_PENALTY_ISA_ALWAYS,    /* IRQ1 keyboard */
0434     PIRQ_PENALTY_ISA_ALWAYS,    /* IRQ2 cascade */
0435     PIRQ_PENALTY_ISA_TYPICAL,   /* IRQ3 serial */
0436     PIRQ_PENALTY_ISA_TYPICAL,   /* IRQ4 serial */
0437     PIRQ_PENALTY_ISA_TYPICAL,   /* IRQ5 sometimes SoundBlaster */
0438     PIRQ_PENALTY_ISA_TYPICAL,   /* IRQ6 */
0439     PIRQ_PENALTY_ISA_TYPICAL,   /* IRQ7 parallel, spurious */
0440     PIRQ_PENALTY_ISA_TYPICAL,   /* IRQ8 rtc, sometimes */
0441     0,              /* IRQ9  PCI, often acpi */
0442     0,              /* IRQ10 PCI */
0443     0,              /* IRQ11 PCI */
0444     PIRQ_PENALTY_ISA_USED,      /* IRQ12 mouse */
0445     PIRQ_PENALTY_ISA_USED,      /* IRQ13 fpe, sometimes */
0446     PIRQ_PENALTY_ISA_USED,      /* IRQ14 ide0 */
0447     PIRQ_PENALTY_ISA_USED,      /* IRQ15 ide1 */
0448     /* >IRQ15 */
0449 };
0450 
0451 static int acpi_irq_pci_sharing_penalty(int irq)
0452 {
0453     struct acpi_pci_link *link;
0454     int penalty = 0;
0455     int i;
0456 
0457     list_for_each_entry(link, &acpi_link_list, list) {
0458         /*
0459          * If a link is active, penalize its IRQ heavily
0460          * so we try to choose a different IRQ.
0461          */
0462         if (link->irq.active && link->irq.active == irq)
0463             penalty += PIRQ_PENALTY_PCI_USING;
0464 
0465         /*
0466          * penalize the IRQs PCI might use, but not as severely.
0467          */
0468         for (i = 0; i < link->irq.possible_count; i++)
0469             if (link->irq.possible[i] == irq)
0470                 penalty += PIRQ_PENALTY_PCI_POSSIBLE /
0471                     link->irq.possible_count;
0472     }
0473 
0474     return penalty;
0475 }
0476 
0477 static int acpi_irq_get_penalty(int irq)
0478 {
0479     int penalty = 0;
0480 
0481     if (irq == sci_irq)
0482         penalty += sci_penalty;
0483 
0484     if (irq < ACPI_MAX_ISA_IRQS)
0485         return penalty + acpi_isa_irq_penalty[irq];
0486 
0487     return penalty + acpi_irq_pci_sharing_penalty(irq);
0488 }
0489 
0490 int __init acpi_irq_penalty_init(void)
0491 {
0492     struct acpi_pci_link *link;
0493     int i;
0494 
0495     /*
0496      * Update penalties to facilitate IRQ balancing.
0497      */
0498     list_for_each_entry(link, &acpi_link_list, list) {
0499 
0500         /*
0501          * reflect the possible and active irqs in the penalty table --
0502          * useful for breaking ties.
0503          */
0504         if (link->irq.possible_count) {
0505             int penalty =
0506                 PIRQ_PENALTY_PCI_POSSIBLE /
0507                 link->irq.possible_count;
0508 
0509             for (i = 0; i < link->irq.possible_count; i++) {
0510                 if (link->irq.possible[i] < ACPI_MAX_ISA_IRQS)
0511                     acpi_isa_irq_penalty[link->irq.
0512                              possible[i]] +=
0513                         penalty;
0514             }
0515 
0516         } else if (link->irq.active &&
0517                 (link->irq.active < ACPI_MAX_ISA_IRQS)) {
0518             acpi_isa_irq_penalty[link->irq.active] +=
0519                 PIRQ_PENALTY_PCI_POSSIBLE;
0520         }
0521     }
0522 
0523     return 0;
0524 }
0525 
0526 static int acpi_irq_balance = -1;   /* 0: static, 1: balance */
0527 
0528 static int acpi_pci_link_allocate(struct acpi_pci_link *link)
0529 {
0530     acpi_handle handle = link->device->handle;
0531     int irq;
0532     int i;
0533 
0534     if (link->irq.initialized) {
0535         if (link->refcnt == 0)
0536             /* This means the link is disabled but initialized */
0537             acpi_pci_link_set(link, link->irq.active);
0538         return 0;
0539     }
0540 
0541     /*
0542      * search for active IRQ in list of possible IRQs.
0543      */
0544     for (i = 0; i < link->irq.possible_count; ++i) {
0545         if (link->irq.active == link->irq.possible[i])
0546             break;
0547     }
0548     /*
0549      * forget active IRQ that is not in possible list
0550      */
0551     if (i == link->irq.possible_count) {
0552         if (acpi_strict)
0553             acpi_handle_warn(handle, "_CRS %d not found in _PRS\n",
0554                      link->irq.active);
0555         link->irq.active = 0;
0556     }
0557 
0558     /*
0559      * if active found, use it; else pick entry from end of possible list.
0560      */
0561     if (link->irq.active)
0562         irq = link->irq.active;
0563     else
0564         irq = link->irq.possible[link->irq.possible_count - 1];
0565 
0566     if (acpi_irq_balance || !link->irq.active) {
0567         /*
0568          * Select the best IRQ.  This is done in reverse to promote
0569          * the use of IRQs 9, 10, 11, and >15.
0570          */
0571         for (i = (link->irq.possible_count - 1); i >= 0; i--) {
0572             if (acpi_irq_get_penalty(irq) >
0573                 acpi_irq_get_penalty(link->irq.possible[i]))
0574                 irq = link->irq.possible[i];
0575         }
0576     }
0577     if (acpi_irq_get_penalty(irq) >= PIRQ_PENALTY_ISA_ALWAYS) {
0578         acpi_handle_err(handle,
0579                 "No IRQ available. Try pci=noacpi or acpi=off\n");
0580         return -ENODEV;
0581     }
0582 
0583     /* Attempt to enable the link device at this IRQ. */
0584     if (acpi_pci_link_set(link, irq)) {
0585         acpi_handle_err(handle,
0586                 "Unable to set IRQ. Try pci=noacpi or acpi=off\n");
0587         return -ENODEV;
0588     } else {
0589         if (link->irq.active < ACPI_MAX_ISA_IRQS)
0590             acpi_isa_irq_penalty[link->irq.active] +=
0591                 PIRQ_PENALTY_PCI_USING;
0592 
0593         acpi_handle_info(handle, "Enabled at IRQ %d\n",
0594                  link->irq.active);
0595     }
0596 
0597     link->irq.initialized = 1;
0598     return 0;
0599 }
0600 
0601 /*
0602  * acpi_pci_link_allocate_irq
0603  * success: return IRQ >= 0
0604  * failure: return -1
0605  */
0606 int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
0607                    int *polarity, char **name)
0608 {
0609     struct acpi_device *device = acpi_fetch_acpi_dev(handle);
0610     struct acpi_pci_link *link;
0611 
0612     if (!device) {
0613         acpi_handle_err(handle, "Invalid link device\n");
0614         return -1;
0615     }
0616 
0617     link = acpi_driver_data(device);
0618     if (!link) {
0619         acpi_handle_err(handle, "Invalid link context\n");
0620         return -1;
0621     }
0622 
0623     /* TBD: Support multiple index (IRQ) entries per Link Device */
0624     if (index) {
0625         acpi_handle_err(handle, "Invalid index %d\n", index);
0626         return -1;
0627     }
0628 
0629     mutex_lock(&acpi_link_lock);
0630     if (acpi_pci_link_allocate(link)) {
0631         mutex_unlock(&acpi_link_lock);
0632         return -1;
0633     }
0634 
0635     if (!link->irq.active) {
0636         mutex_unlock(&acpi_link_lock);
0637         acpi_handle_err(handle, "Link active IRQ is 0!\n");
0638         return -1;
0639     }
0640     link->refcnt++;
0641     mutex_unlock(&acpi_link_lock);
0642 
0643     if (triggering)
0644         *triggering = link->irq.triggering;
0645     if (polarity)
0646         *polarity = link->irq.polarity;
0647     if (name)
0648         *name = acpi_device_bid(link->device);
0649     acpi_handle_debug(handle, "Link is referenced\n");
0650     return link->irq.active;
0651 }
0652 
0653 /*
0654  * We don't change link's irq information here.  After it is reenabled, we
0655  * continue use the info
0656  */
0657 int acpi_pci_link_free_irq(acpi_handle handle)
0658 {
0659     struct acpi_device *device = acpi_fetch_acpi_dev(handle);
0660     struct acpi_pci_link *link;
0661 
0662     if (!device) {
0663         acpi_handle_err(handle, "Invalid link device\n");
0664         return -1;
0665     }
0666 
0667     link = acpi_driver_data(device);
0668     if (!link) {
0669         acpi_handle_err(handle, "Invalid link context\n");
0670         return -1;
0671     }
0672 
0673     mutex_lock(&acpi_link_lock);
0674     if (!link->irq.initialized) {
0675         mutex_unlock(&acpi_link_lock);
0676         acpi_handle_err(handle, "Link isn't initialized\n");
0677         return -1;
0678     }
0679 #ifdef  FUTURE_USE
0680     /*
0681      * The Link reference count allows us to _DISable an unused link
0682      * and suspend time, and set it again  on resume.
0683      * However, 2.6.12 still has irq_router.resume
0684      * which blindly restores the link state.
0685      * So we disable the reference count method
0686      * to prevent duplicate acpi_pci_link_set()
0687      * which would harm some systems
0688      */
0689     link->refcnt--;
0690 #endif
0691     acpi_handle_debug(handle, "Link is dereferenced\n");
0692 
0693     if (link->refcnt == 0)
0694         acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL);
0695 
0696     mutex_unlock(&acpi_link_lock);
0697     return link->irq.active;
0698 }
0699 
0700 /* --------------------------------------------------------------------------
0701                                  Driver Interface
0702    -------------------------------------------------------------------------- */
0703 
0704 static int acpi_pci_link_add(struct acpi_device *device,
0705                  const struct acpi_device_id *not_used)
0706 {
0707     acpi_handle handle = device->handle;
0708     struct acpi_pci_link *link;
0709     int result;
0710     int i;
0711 
0712     link = kzalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
0713     if (!link)
0714         return -ENOMEM;
0715 
0716     link->device = device;
0717     strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
0718     strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
0719     device->driver_data = link;
0720 
0721     mutex_lock(&acpi_link_lock);
0722     result = acpi_pci_link_get_possible(link);
0723     if (result)
0724         goto end;
0725 
0726     /* query and set link->irq.active */
0727     acpi_pci_link_get_current(link);
0728 
0729     pr_info("Interrupt link %s configured for IRQ %d\n",
0730         acpi_device_bid(device), link->irq.active);
0731 
0732     for (i = 0; i < link->irq.possible_count; i++) {
0733         if (link->irq.active != link->irq.possible[i])
0734             acpi_handle_debug(handle, "Possible IRQ %d\n",
0735                       link->irq.possible[i]);
0736     }
0737 
0738     if (!link->device->status.enabled)
0739         pr_info("Interrupt link %s disabled\n", acpi_device_bid(device));
0740 
0741     list_add_tail(&link->list, &acpi_link_list);
0742 
0743       end:
0744     /* disable all links -- to be activated on use */
0745     acpi_evaluate_object(handle, "_DIS", NULL, NULL);
0746     mutex_unlock(&acpi_link_lock);
0747 
0748     if (result)
0749         kfree(link);
0750 
0751     return result < 0 ? result : 1;
0752 }
0753 
0754 static int acpi_pci_link_resume(struct acpi_pci_link *link)
0755 {
0756     if (link->refcnt && link->irq.active && link->irq.initialized)
0757         return (acpi_pci_link_set(link, link->irq.active));
0758 
0759     return 0;
0760 }
0761 
0762 static void irqrouter_resume(void)
0763 {
0764     struct acpi_pci_link *link;
0765 
0766     list_for_each_entry(link, &acpi_link_list, list) {
0767         acpi_pci_link_resume(link);
0768     }
0769 }
0770 
0771 static void acpi_pci_link_remove(struct acpi_device *device)
0772 {
0773     struct acpi_pci_link *link;
0774 
0775     link = acpi_driver_data(device);
0776 
0777     mutex_lock(&acpi_link_lock);
0778     list_del(&link->list);
0779     mutex_unlock(&acpi_link_lock);
0780 
0781     kfree(link);
0782 }
0783 
0784 /*
0785  * modify acpi_isa_irq_penalty[] from cmdline
0786  */
0787 static int __init acpi_irq_penalty_update(char *str, int used)
0788 {
0789     int i;
0790 
0791     for (i = 0; i < 16; i++) {
0792         int retval;
0793         int irq;
0794         int new_penalty;
0795 
0796         retval = get_option(&str, &irq);
0797 
0798         if (!retval)
0799             break;  /* no number found */
0800 
0801         /* see if this is a ISA IRQ */
0802         if ((irq < 0) || (irq >= ACPI_MAX_ISA_IRQS))
0803             continue;
0804 
0805         if (used)
0806             new_penalty = acpi_isa_irq_penalty[irq] +
0807                     PIRQ_PENALTY_ISA_USED;
0808         else
0809             new_penalty = 0;
0810 
0811         acpi_isa_irq_penalty[irq] = new_penalty;
0812         if (retval != 2)    /* no next number */
0813             break;
0814     }
0815     return 1;
0816 }
0817 
0818 /*
0819  * We'd like PNP to call this routine for the
0820  * single ISA_USED value for each legacy device.
0821  * But instead it calls us with each POSSIBLE setting.
0822  * There is no ISA_POSSIBLE weight, so we simply use
0823  * the (small) PCI_USING penalty.
0824  */
0825 void acpi_penalize_isa_irq(int irq, int active)
0826 {
0827     if ((irq >= 0) && (irq < ARRAY_SIZE(acpi_isa_irq_penalty)))
0828         acpi_isa_irq_penalty[irq] +=
0829           (active ? PIRQ_PENALTY_ISA_USED : PIRQ_PENALTY_PCI_USING);
0830 }
0831 
0832 bool acpi_isa_irq_available(int irq)
0833 {
0834     return irq >= 0 && (irq >= ARRAY_SIZE(acpi_isa_irq_penalty) ||
0835             acpi_irq_get_penalty(irq) < PIRQ_PENALTY_ISA_ALWAYS);
0836 }
0837 
0838 void acpi_penalize_sci_irq(int irq, int trigger, int polarity)
0839 {
0840     sci_irq = irq;
0841 
0842     if (trigger == ACPI_MADT_TRIGGER_LEVEL &&
0843         polarity == ACPI_MADT_POLARITY_ACTIVE_LOW)
0844         sci_penalty = PIRQ_PENALTY_PCI_USING;
0845     else
0846         sci_penalty = PIRQ_PENALTY_ISA_ALWAYS;
0847 }
0848 
0849 /*
0850  * Over-ride default table to reserve additional IRQs for use by ISA
0851  * e.g. acpi_irq_isa=5
0852  * Useful for telling ACPI how not to interfere with your ISA sound card.
0853  */
0854 static int __init acpi_irq_isa(char *str)
0855 {
0856     return acpi_irq_penalty_update(str, 1);
0857 }
0858 
0859 __setup("acpi_irq_isa=", acpi_irq_isa);
0860 
0861 /*
0862  * Over-ride default table to free additional IRQs for use by PCI
0863  * e.g. acpi_irq_pci=7,15
0864  * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
0865  */
0866 static int __init acpi_irq_pci(char *str)
0867 {
0868     return acpi_irq_penalty_update(str, 0);
0869 }
0870 
0871 __setup("acpi_irq_pci=", acpi_irq_pci);
0872 
0873 static int __init acpi_irq_nobalance_set(char *str)
0874 {
0875     acpi_irq_balance = 0;
0876     return 1;
0877 }
0878 
0879 __setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
0880 
0881 static int __init acpi_irq_balance_set(char *str)
0882 {
0883     acpi_irq_balance = 1;
0884     return 1;
0885 }
0886 
0887 __setup("acpi_irq_balance", acpi_irq_balance_set);
0888 
0889 static struct syscore_ops irqrouter_syscore_ops = {
0890     .resume = irqrouter_resume,
0891 };
0892 
0893 void __init acpi_pci_link_init(void)
0894 {
0895     if (acpi_noirq)
0896         return;
0897 
0898     if (acpi_irq_balance == -1) {
0899         /* no command line switch: enable balancing in IOAPIC mode */
0900         if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
0901             acpi_irq_balance = 1;
0902         else
0903             acpi_irq_balance = 0;
0904     }
0905     register_syscore_ops(&irqrouter_syscore_ops);
0906     acpi_scan_add_handler(&pci_link_handler);
0907 }
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