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(object: handle, ACPI_FULL_PATHNAME, ret_path_ptr: &string); |
44 | |
45 | /* run OSHP */ |
46 | status = acpi_evaluate_object(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(objp: string.pointer); |
59 | return status; |
60 | } |
61 | |
62 | /** |
63 | * acpi_get_hp_hw_control_from_firmware |
64 | * @pdev: 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 | * If there's no ACPI host bridge (i.e., ACPI support is compiled |
78 | * into the kernel but the hardware platform doesn't support ACPI), |
79 | * there's nothing to do here. |
80 | */ |
81 | host = pci_find_host_bridge(bus: pdev->bus); |
82 | root = acpi_pci_find_root(ACPI_HANDLE(&host->dev)); |
83 | if (!root) |
84 | return 0; |
85 | |
86 | /* |
87 | * If _OSC exists, it determines whether we're allowed to manage |
88 | * the SHPC. We executed it while enumerating the host bridge. |
89 | */ |
90 | if (root->osc_support_set) { |
91 | if (host->native_shpc_hotplug) |
92 | return 0; |
93 | return -ENODEV; |
94 | } |
95 | |
96 | /* |
97 | * In the absence of _OSC, we're always allowed to manage the SHPC. |
98 | * However, if an OSHP method is present, we must execute it so the |
99 | * firmware can transfer control to the OS, e.g., direct interrupts |
100 | * to the OS instead of to the firmware. |
101 | * |
102 | * N.B. The PCI Firmware Spec (r3.2, sec 4.8) does not endorse |
103 | * searching up the ACPI hierarchy, so the loops below are suspect. |
104 | */ |
105 | handle = ACPI_HANDLE(&pdev->dev); |
106 | if (!handle) { |
107 | /* |
108 | * This hotplug controller was not listed in the ACPI name |
109 | * space at all. Try to get ACPI handle of parent PCI bus. |
110 | */ |
111 | struct pci_bus *pbus; |
112 | for (pbus = pdev->bus; pbus; pbus = pbus->parent) { |
113 | handle = acpi_pci_get_bridge_handle(pbus); |
114 | if (handle) |
115 | break; |
116 | } |
117 | } |
118 | |
119 | while (handle) { |
120 | acpi_get_name(object: handle, ACPI_FULL_PATHNAME, ret_path_ptr: &string); |
121 | pci_info(pdev, "Requesting control of SHPC hotplug via OSHP (%s)\n" , |
122 | (char *)string.pointer); |
123 | status = acpi_run_oshp(handle); |
124 | if (ACPI_SUCCESS(status)) |
125 | goto got_one; |
126 | if (acpi_is_root_bridge(handle)) |
127 | break; |
128 | chandle = handle; |
129 | status = acpi_get_parent(object: chandle, out_handle: &handle); |
130 | if (ACPI_FAILURE(status)) |
131 | break; |
132 | } |
133 | |
134 | pci_info(pdev, "Cannot get control of SHPC hotplug\n" ); |
135 | kfree(objp: string.pointer); |
136 | return -ENODEV; |
137 | got_one: |
138 | pci_info(pdev, "Gained control of SHPC hotplug (%s)\n" , |
139 | (char *)string.pointer); |
140 | kfree(objp: string.pointer); |
141 | return 0; |
142 | } |
143 | EXPORT_SYMBOL(acpi_get_hp_hw_control_from_firmware); |
144 | |
145 | static int pcihp_is_ejectable(acpi_handle handle) |
146 | { |
147 | acpi_status status; |
148 | unsigned long long removable; |
149 | if (!acpi_has_method(handle, name: "_ADR" )) |
150 | return 0; |
151 | if (acpi_has_method(handle, name: "_EJ0" )) |
152 | return 1; |
153 | status = acpi_evaluate_integer(handle, pathname: "_RMV" , NULL, data: &removable); |
154 | if (ACPI_SUCCESS(status) && removable) |
155 | return 1; |
156 | return 0; |
157 | } |
158 | |
159 | /** |
160 | * acpi_pci_check_ejectable - check if handle is ejectable ACPI PCI slot |
161 | * @pbus: the PCI bus of the PCI slot corresponding to 'handle' |
162 | * @handle: ACPI handle to check |
163 | * |
164 | * Return 1 if handle is ejectable PCI slot, 0 otherwise. |
165 | */ |
166 | int acpi_pci_check_ejectable(struct pci_bus *pbus, acpi_handle handle) |
167 | { |
168 | acpi_handle bridge_handle, parent_handle; |
169 | |
170 | bridge_handle = acpi_pci_get_bridge_handle(pbus); |
171 | if (!bridge_handle) |
172 | return 0; |
173 | if ((ACPI_FAILURE(acpi_get_parent(handle, &parent_handle)))) |
174 | return 0; |
175 | if (bridge_handle != parent_handle) |
176 | return 0; |
177 | return pcihp_is_ejectable(handle); |
178 | } |
179 | EXPORT_SYMBOL_GPL(acpi_pci_check_ejectable); |
180 | |
181 | static acpi_status |
182 | check_hotplug(acpi_handle handle, u32 lvl, void *context, void **rv) |
183 | { |
184 | int *found = (int *)context; |
185 | if (pcihp_is_ejectable(handle)) { |
186 | *found = 1; |
187 | return AE_CTRL_TERMINATE; |
188 | } |
189 | return AE_OK; |
190 | } |
191 | |
192 | /** |
193 | * acpi_pci_detect_ejectable - check if the PCI bus has ejectable slots |
194 | * @handle: handle of the PCI bus to scan |
195 | * |
196 | * Returns 1 if the PCI bus has ACPI based ejectable slots, 0 otherwise. |
197 | */ |
198 | int acpi_pci_detect_ejectable(acpi_handle handle) |
199 | { |
200 | int found = 0; |
201 | |
202 | if (!handle) |
203 | return found; |
204 | |
205 | acpi_walk_namespace(ACPI_TYPE_DEVICE, start_object: handle, max_depth: 1, |
206 | descending_callback: check_hotplug, NULL, context: (void *)&found, NULL); |
207 | return found; |
208 | } |
209 | EXPORT_SYMBOL_GPL(acpi_pci_detect_ejectable); |
210 | |
211 | module_param(debug_acpi, bool, 0644); |
212 | MODULE_PARM_DESC(debug_acpi, "Debugging mode for ACPI enabled or not" ); |
213 | |