drivers/pci/hotplug/acpi_pcihp.c

   1 /*
   2  * Common ACPI functions for hot plug platforms
   3  *
   4  * Copyright (C) 2006 Intel Corporation
   5  *
   6  * All rights reserved.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or (at
  11  * your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  16  * NON INFRINGEMENT.  See the GNU General Public License for more
  17  * details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22  *
  23  * Send feedback to <kristen.c.accardi@intel.com>
  24  *
  25  */
  26
  27 #include <linux/module.h>
  28 #include <linux/moduleparam.h>
  29 #include <linux/kernel.h>
  30 #include <linux/types.h>
  31 #include <linux/pci.h>
  32 #include <linux/pci_hotplug.h>
  33 #include <linux/acpi.h>
  34 #include <linux/pci-acpi.h>
  35 #include <linux/slab.h>
  36
  37 #define MY_NAME "acpi_pcihp"
  38
  39 #define dbg(fmt, arg...) do { if (debug_acpi) printk(KERN_DEBUG "%s: %s: " fmt, MY_NAME, __func__, ## arg); } while (0)
  40 #define err(format, arg...) printk(KERN_ERR "%s: " format, MY_NAME, ## arg)
  41 #define info(format, arg...) printk(KERN_INFO "%s: " format, MY_NAME, ## arg)
  42 #define warn(format, arg...) printk(KERN_WARNING "%s: " format, MY_NAME, ## arg)
  43
  44 #define METHOD_NAME__SUN        "_SUN"
  45 #define METHOD_NAME_OSHP        "OSHP"
  46
  47 static bool debug_acpi;
  48
  49 /* acpi_run_oshp - get control of hotplug from the firmware
  50  *
  51  * @handle - the handle of the hotplug controller.
  52  */
  53 static acpi_status acpi_run_oshp(acpi_handle handle)
  54 {
  55         acpi_status             status;
  56         struct acpi_buffer      string = { ACPI_ALLOCATE_BUFFER, NULL };
  57
  58         acpi_get_name(handle, ACPI_FULL_PATHNAME, &string);
  59
  60         /* run OSHP */
  61         status = acpi_evaluate_object(handle, METHOD_NAME_OSHP, NULL, NULL);
  62         if (ACPI_FAILURE(status))
  63                 if (status != AE_NOT_FOUND)
  64                         printk(KERN_ERR "%s:%s OSHP fails=0x%x\n",
  65                                __func__, (char *)string.pointer, status);
  66                 else
  67                         dbg("%s:%s OSHP not found\n",
  68                             __func__, (char *)string.pointer);
  69         else
  70                 pr_debug("%s:%s OSHP passes\n", __func__,
  71                         (char *)string.pointer);
  72
  73         kfree(string.pointer);
  74         return status;
  75 }
  76
  77 /**
  78  * acpi_get_hp_hw_control_from_firmware
  79  * @dev: the pci_dev of the bridge that has a hotplug controller
  80  * @flags: requested control bits for _OSC
  81  *
  82  * Attempt to take hotplug control from firmware.
  83  */
  84 int acpi_get_hp_hw_control_from_firmware(struct pci_dev *pdev, u32 flags)
  85 {
  86         acpi_status status;
  87         acpi_handle chandle, handle;
  88         struct acpi_buffer string = { ACPI_ALLOCATE_BUFFER, NULL };
  89
  90         flags &= OSC_PCI_SHPC_NATIVE_HP_CONTROL;
  91         if (!flags) {
  92                 err("Invalid flags %u specified!\n", flags);
  93                 return -EINVAL;
  94         }
  95
  96         /*
  97          * Per PCI firmware specification, we should run the ACPI _OSC
  98          * method to get control of hotplug hardware before using it. If
  99          * an _OSC is missing, we look for an OSHP to do the same thing.
 100          * To handle different BIOS behavior, we look for _OSC on a root
 101          * bridge preferentially (according to PCI fw spec). Later for
 102          * OSHP within the scope of the hotplug controller and its parents,
 103          * up to the host bridge under which this controller exists.
 104          */
 105         handle = acpi_find_root_bridge_handle(pdev);
 106         if (handle) {
 107                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &string);
 108                 dbg("Trying to get hotplug control for %s\n",
 109                                 (char *)string.pointer);
 110                 status = acpi_pci_osc_control_set(handle, &flags, flags);
 111                 if (ACPI_SUCCESS(status))
 112                         goto got_one;
 113                 if (status == AE_SUPPORT)
 114                         goto no_control;
 115                 kfree(string.pointer);
 116                 string = (struct acpi_buffer){ ACPI_ALLOCATE_BUFFER, NULL };
 117         }
 118
 119         handle = ACPI_HANDLE(&pdev->dev);
 120         if (!handle) {
 121                 /*
 122                  * This hotplug controller was not listed in the ACPI name
 123                  * space at all. Try to get acpi handle of parent pci bus.
 124                  */
 125                 struct pci_bus *pbus;
 126                 for (pbus = pdev->bus; pbus; pbus = pbus->parent) {
 127                         handle = acpi_pci_get_bridge_handle(pbus);
 128                         if (handle)
 129                                 break;
 130                 }
 131         }
 132
 133         while (handle) {
 134                 acpi_get_name(handle, ACPI_FULL_PATHNAME, &string);
 135                 dbg("Trying to get hotplug control for %s\n",
 136                     (char *)string.pointer);
 137                 status = acpi_run_oshp(handle);
 138                 if (ACPI_SUCCESS(status))
 139                         goto got_one;
 140                 if (acpi_is_root_bridge(handle))
 141                         break;
 142                 chandle = handle;
 143                 status = acpi_get_parent(chandle, &handle);
 144                 if (ACPI_FAILURE(status))
 145                         break;
 146         }
 147 no_control:
 148         dbg("Cannot get control of hotplug hardware for pci %s\n",
 149             pci_name(pdev));
 150         kfree(string.pointer);
 151         return -ENODEV;
 152 got_one:
 153         dbg("Gained control for hotplug HW for pci %s (%s)\n",
 154             pci_name(pdev), (char *)string.pointer);
 155         kfree(string.pointer);
 156         return 0;
 157 }
 158 EXPORT_SYMBOL(acpi_get_hp_hw_control_from_firmware);
 159
 160 static int pcihp_is_ejectable(acpi_handle handle)
 161 {
 162         acpi_status status;
 163         unsigned long long removable;
 164         if (!acpi_has_method(handle, "_ADR"))
 165                 return 0;
 166         if (acpi_has_method(handle, "_EJ0"))
 167                 return 1;
 168         status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
 169         if (ACPI_SUCCESS(status) && removable)
 170                 return 1;
 171         return 0;
 172 }
 173
 174 /**
 175  * acpi_pcihp_check_ejectable - check if handle is ejectable ACPI PCI slot
 176  * @pbus: the PCI bus of the PCI slot corresponding to 'handle'
 177  * @handle: ACPI handle to check
 178  *
 179  * Return 1 if handle is ejectable PCI slot, 0 otherwise.
 180  */
 181 int acpi_pci_check_ejectable(struct pci_bus *pbus, acpi_handle handle)
 182 {
 183         acpi_handle bridge_handle, parent_handle;
 184
 185         bridge_handle = acpi_pci_get_bridge_handle(pbus);
 186         if (!bridge_handle)
 187                 return 0;
 188         if ((ACPI_FAILURE(acpi_get_parent(handle, &parent_handle))))
 189                 return 0;
 190         if (bridge_handle != parent_handle)
 191                 return 0;
 192         return pcihp_is_ejectable(handle);
 193 }
 194 EXPORT_SYMBOL_GPL(acpi_pci_check_ejectable);
 195
 196 static acpi_status
 197 check_hotplug(acpi_handle handle, u32 lvl, void *context, void **rv)
 198 {
 199         int *found = (int *)context;
 200         if (pcihp_is_ejectable(handle)) {
 201                 *found = 1;
 202                 return AE_CTRL_TERMINATE;
 203         }
 204         return AE_OK;
 205 }
 206
 207 /**
 208  * acpi_pci_detect_ejectable - check if the PCI bus has ejectable slots
 209  * @handle - handle of the PCI bus to scan
 210  *
 211  * Returns 1 if the PCI bus has ACPI based ejectable slots, 0 otherwise.
 212  */
 213 int acpi_pci_detect_ejectable(acpi_handle handle)
 214 {
 215         int found = 0;
 216
 217         if (!handle)
 218                 return found;
 219
 220         acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
 221                             check_hotplug, NULL, (void *)&found, NULL);
 222         return found;
 223 }
 224 EXPORT_SYMBOL_GPL(acpi_pci_detect_ejectable);
 225
 226 module_param(debug_acpi, bool, 0644);
 227 MODULE_PARM_DESC(debug_acpi, "Debugging mode for ACPI enabled or not");