1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Common ACPI functions for hot plug platforms 4 * 5 * Copyright (C) 2006 Intel Corporation 6 * 7 * All rights reserved. 8 * 9 * Send feedback to <kristen.c.accardi@intel.com> 10 */ 11 12 #include <linux/module.h> 13 #include <linux/moduleparam.h> 14 #include <linux/kernel.h> 15 #include <linux/types.h> 16 #include <linux/pci.h> 17 #include <linux/pci_hotplug.h> 18 #include <linux/acpi.h> 19 #include <linux/pci-acpi.h> 20 #include <linux/slab.h> 21 22 #define MY_NAME "acpi_pcihp" 23 24 #define dbg(fmt, arg...) do { if (debug_acpi) printk(KERN_DEBUG "%s: %s: " fmt, MY_NAME, __func__, ## arg); } while (0) 25 #define err(format, arg...) printk(KERN_ERR "%s: " format, MY_NAME, ## arg) 26 #define info(format, arg...) printk(KERN_INFO "%s: " format, MY_NAME, ## arg) 27 #define warn(format, arg...) printk(KERN_WARNING "%s: " format, MY_NAME, ## arg) 28 29 #define METHOD_NAME__SUN "_SUN" 30 #define METHOD_NAME_OSHP "OSHP" 31 32 static bool debug_acpi; 33 34 /* acpi_run_oshp - get control of hotplug from the firmware 35 * 36 * @handle - the handle of the hotplug controller. 37 */ 38 static acpi_status acpi_run_oshp(acpi_handle handle) 39 { 40 acpi_status status; 41 struct acpi_buffer string = { ACPI_ALLOCATE_BUFFER, NULL }; 42 43 acpi_get_name(handle, ACPI_FULL_PATHNAME, &string); 44 45 /* run OSHP */ 46 status = acpi_evaluate_object(handle, METHOD_NAME_OSHP, NULL, NULL); 47 if (ACPI_FAILURE(status)) 48 if (status != AE_NOT_FOUND) 49 printk(KERN_ERR "%s:%s OSHP fails=0x%x\n", 50 __func__, (char *)string.pointer, status); 51 else 52 dbg("%s:%s OSHP not found\n", 53 __func__, (char *)string.pointer); 54 else 55 pr_debug("%s:%s OSHP passes\n", __func__, 56 (char *)string.pointer); 57 58 kfree(string.pointer); 59 return status; 60 } 61 62 /** 63 * acpi_get_hp_hw_control_from_firmware 64 * @dev: the pci_dev of the bridge that has a hotplug controller 65 * 66 * Attempt to take hotplug control from firmware. 67 */ 68 int acpi_get_hp_hw_control_from_firmware(struct pci_dev *pdev) 69 { 70 const struct pci_host_bridge *host; 71 const struct acpi_pci_root *root; 72 acpi_status status; 73 acpi_handle chandle, handle; 74 struct acpi_buffer string = { ACPI_ALLOCATE_BUFFER, NULL }; 75 76 /* 77 * Per PCI firmware specification, we should run the ACPI _OSC 78 * method to get control of hotplug hardware before using it. If 79 * an _OSC is missing, we look for an OSHP to do the same thing. 80 * To handle different BIOS behavior, we look for _OSC on a root 81 * bridge preferentially (according to PCI fw spec). Later for 82 * OSHP within the scope of the hotplug controller and its parents, 83 * up to the host bridge under which this controller exists. 84 */ 85 if (shpchp_is_native(pdev)) 86 return 0; 87 88 /* If _OSC exists, we should not evaluate OSHP */ 89 90 /* 91 * If there's no ACPI host bridge (i.e., ACPI support is compiled 92 * into the kernel but the hardware platform doesn't support ACPI), 93 * there's nothing to do here. 94 */ 95 host = pci_find_host_bridge(pdev->bus); 96 root = acpi_pci_find_root(ACPI_HANDLE(&host->dev)); 97 if (!root) 98 return 0; 99 100 if (root->osc_support_set) 101 goto no_control; 102 103 handle = ACPI_HANDLE(&pdev->dev); 104 if (!handle) { 105 /* 106 * This hotplug controller was not listed in the ACPI name 107 * space at all. Try to get ACPI handle of parent PCI bus. 108 */ 109 struct pci_bus *pbus; 110 for (pbus = pdev->bus; pbus; pbus = pbus->parent) { 111 handle = acpi_pci_get_bridge_handle(pbus); 112 if (handle) 113 break; 114 } 115 } 116 117 while (handle) { 118 acpi_get_name(handle, ACPI_FULL_PATHNAME, &string); 119 pci_info(pdev, "Requesting control of SHPC hotplug via OSHP (%s)\n", 120 (char *)string.pointer); 121 status = acpi_run_oshp(handle); 122 if (ACPI_SUCCESS(status)) 123 goto got_one; 124 if (acpi_is_root_bridge(handle)) 125 break; 126 chandle = handle; 127 status = acpi_get_parent(chandle, &handle); 128 if (ACPI_FAILURE(status)) 129 break; 130 } 131 no_control: 132 pci_info(pdev, "Cannot get control of SHPC hotplug\n"); 133 kfree(string.pointer); 134 return -ENODEV; 135 got_one: 136 pci_info(pdev, "Gained control of SHPC hotplug (%s)\n", 137 (char *)string.pointer); 138 kfree(string.pointer); 139 return 0; 140 } 141 EXPORT_SYMBOL(acpi_get_hp_hw_control_from_firmware); 142 143 static int pcihp_is_ejectable(acpi_handle handle) 144 { 145 acpi_status status; 146 unsigned long long removable; 147 if (!acpi_has_method(handle, "_ADR")) 148 return 0; 149 if (acpi_has_method(handle, "_EJ0")) 150 return 1; 151 status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable); 152 if (ACPI_SUCCESS(status) && removable) 153 return 1; 154 return 0; 155 } 156 157 /** 158 * acpi_pcihp_check_ejectable - check if handle is ejectable ACPI PCI slot 159 * @pbus: the PCI bus of the PCI slot corresponding to 'handle' 160 * @handle: ACPI handle to check 161 * 162 * Return 1 if handle is ejectable PCI slot, 0 otherwise. 163 */ 164 int acpi_pci_check_ejectable(struct pci_bus *pbus, acpi_handle handle) 165 { 166 acpi_handle bridge_handle, parent_handle; 167 168 bridge_handle = acpi_pci_get_bridge_handle(pbus); 169 if (!bridge_handle) 170 return 0; 171 if ((ACPI_FAILURE(acpi_get_parent(handle, &parent_handle)))) 172 return 0; 173 if (bridge_handle != parent_handle) 174 return 0; 175 return pcihp_is_ejectable(handle); 176 } 177 EXPORT_SYMBOL_GPL(acpi_pci_check_ejectable); 178 179 static acpi_status 180 check_hotplug(acpi_handle handle, u32 lvl, void *context, void **rv) 181 { 182 int *found = (int *)context; 183 if (pcihp_is_ejectable(handle)) { 184 *found = 1; 185 return AE_CTRL_TERMINATE; 186 } 187 return AE_OK; 188 } 189 190 /** 191 * acpi_pci_detect_ejectable - check if the PCI bus has ejectable slots 192 * @handle - handle of the PCI bus to scan 193 * 194 * Returns 1 if the PCI bus has ACPI based ejectable slots, 0 otherwise. 195 */ 196 int acpi_pci_detect_ejectable(acpi_handle handle) 197 { 198 int found = 0; 199 200 if (!handle) 201 return found; 202 203 acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1, 204 check_hotplug, NULL, (void *)&found, NULL); 205 return found; 206 } 207 EXPORT_SYMBOL_GPL(acpi_pci_detect_ejectable); 208 209 module_param(debug_acpi, bool, 0644); 210 MODULE_PARM_DESC(debug_acpi, "Debugging mode for ACPI enabled or not"); 211