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  1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * PCI Hot Plug Controller Skeleton Driver - 0.3
  4 *
  5 * Copyright (C) 2001,2003 Greg Kroah-Hartman (greg@kroah.com)
  6 * Copyright (C) 2001,2003 IBM Corp.
  7 *
  8 * All rights reserved.
  9 *
 10 * This driver is to be used as a skeleton driver to show how to interface
 11 * with the pci hotplug core easily.
 12 *
 13 * Send feedback to <greg@kroah.com>
 14 *
 15 */
 16
 17#include <linux/module.h>
 18#include <linux/moduleparam.h>
 19#include <linux/kernel.h>
 20#include <linux/slab.h>
 21#include <linux/pci.h>
 22#include <linux/pci_hotplug.h>
 23#include <linux/init.h>
 24
 25#define SLOT_NAME_SIZE	10
 26struct slot {
 27	u8 number;
 28	struct hotplug_slot *hotplug_slot;
 29	struct list_head slot_list;
 30	char name[SLOT_NAME_SIZE];
 31};
 32
 33static LIST_HEAD(slot_list);
 34
 35#define MY_NAME	"pcihp_skeleton"
 36
 37#define dbg(format, arg...)					\
 38	do {							\
 39		if (debug)					\
 40			printk(KERN_DEBUG "%s: " format "\n",	\
 41				MY_NAME, ## arg);		\
 42	} while (0)
 43#define err(format, arg...) printk(KERN_ERR "%s: " format "\n", MY_NAME, ## arg)
 44#define info(format, arg...) printk(KERN_INFO "%s: " format "\n", MY_NAME, ## arg)
 45#define warn(format, arg...) printk(KERN_WARNING "%s: " format "\n", MY_NAME, ## arg)
 46
 47/* local variables */
 48static bool debug;
 49static int num_slots;
 50
 51#define DRIVER_VERSION	"0.3"
 52#define DRIVER_AUTHOR	"Greg Kroah-Hartman <greg@kroah.com>"
 53#define DRIVER_DESC	"Hot Plug PCI Controller Skeleton Driver"
 54
 55MODULE_AUTHOR(DRIVER_AUTHOR);
 56MODULE_DESCRIPTION(DRIVER_DESC);
 57MODULE_LICENSE("GPL");
 58module_param(debug, bool, 0644);
 59MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
 60
 61static int enable_slot(struct hotplug_slot *slot);
 62static int disable_slot(struct hotplug_slot *slot);
 63static int set_attention_status(struct hotplug_slot *slot, u8 value);
 64static int hardware_test(struct hotplug_slot *slot, u32 value);
 65static int get_power_status(struct hotplug_slot *slot, u8 *value);
 66static int get_attention_status(struct hotplug_slot *slot, u8 *value);
 67static int get_latch_status(struct hotplug_slot *slot, u8 *value);
 68static int get_adapter_status(struct hotplug_slot *slot, u8 *value);
 69
 70static struct hotplug_slot_ops skel_hotplug_slot_ops = {
 71	.enable_slot =		enable_slot,
 72	.disable_slot =		disable_slot,
 73	.set_attention_status =	set_attention_status,
 74	.hardware_test =	hardware_test,
 75	.get_power_status =	get_power_status,
 76	.get_attention_status =	get_attention_status,
 77	.get_latch_status =	get_latch_status,
 78	.get_adapter_status =	get_adapter_status,
 79};
 80
 81static int enable_slot(struct hotplug_slot *hotplug_slot)
 82{
 83	struct slot *slot = hotplug_slot->private;
 84	int retval = 0;
 85
 86	dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
 87
 88	/*
 89	 * Fill in code here to enable the specified slot
 90	 */
 91
 92	return retval;
 93}
 94
 95static int disable_slot(struct hotplug_slot *hotplug_slot)
 96{
 97	struct slot *slot = hotplug_slot->private;
 98	int retval = 0;
 99
100	dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
101
102	/*
103	 * Fill in code here to disable the specified slot
104	 */
105
106	return retval;
107}
108
109static int set_attention_status(struct hotplug_slot *hotplug_slot, u8 status)
110{
111	struct slot *slot = hotplug_slot->private;
112	int retval = 0;
113
114	dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
115
116	switch (status) {
117	case 0:
118		/*
119		 * Fill in code here to turn light off
120		 */
121		break;
122
123	case 1:
124	default:
125		/*
126		 * Fill in code here to turn light on
127		 */
128		break;
129	}
130
131	return retval;
132}
133
134static int hardware_test(struct hotplug_slot *hotplug_slot, u32 value)
135{
136	struct slot *slot = hotplug_slot->private;
137	int retval = 0;
138
139	dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
140
141	switch (value) {
142	case 0:
143		/* Specify a test here */
144		break;
145	case 1:
146		/* Specify another test here */
147		break;
148	}
149
150	return retval;
151}
152
153static int get_power_status(struct hotplug_slot *hotplug_slot, u8 *value)
154{
155	struct slot *slot = hotplug_slot->private;
156	int retval = 0;
157
158	dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
159
160	/*
161	 * Fill in logic to get the current power status of the specific
162	 * slot and store it in the *value location.
163	 */
164
165	return retval;
166}
167
168static int get_attention_status(struct hotplug_slot *hotplug_slot, u8 *value)
169{
170	struct slot *slot = hotplug_slot->private;
171	int retval = 0;
172
173	dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
174
175	/*
176	 * Fill in logic to get the current attention status of the specific
177	 * slot and store it in the *value location.
178	 */
179
180	return retval;
181}
182
183static int get_latch_status(struct hotplug_slot *hotplug_slot, u8 *value)
184{
185	struct slot *slot = hotplug_slot->private;
186	int retval = 0;
187
188	dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
189
190	/*
191	 * Fill in logic to get the current latch status of the specific
192	 * slot and store it in the *value location.
193	 */
194
195	return retval;
196}
197
198static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value)
199{
200	struct slot *slot = hotplug_slot->private;
201	int retval = 0;
202
203	dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
204
205	/*
206	 * Fill in logic to get the current adapter status of the specific
207	 * slot and store it in the *value location.
208	 */
209
210	return retval;
211}
212
213static void release_slot(struct hotplug_slot *hotplug_slot)
214{
215	struct slot *slot = hotplug_slot->private;
216
217	dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
218	kfree(slot->hotplug_slot->info);
219	kfree(slot->hotplug_slot);
220	kfree(slot);
221}
222
223static void make_slot_name(struct slot *slot)
224{
225	/*
226	 * Stupid way to make a filename out of the slot name.
227	 * replace this if your hardware provides a better way to name slots.
228	 */
229	snprintf(slot->hotplug_slot->name, SLOT_NAME_SIZE, "%d", slot->number);
230}
231
232/**
233 * init_slots - initialize 'struct slot' structures for each slot
234 *
235 */
236static int __init init_slots(void)
237{
238	struct slot *slot;
239	struct hotplug_slot *hotplug_slot;
240	struct hotplug_slot_info *info;
241	int retval;
242	int i;
243
244	/*
245	 * Create a structure for each slot, and register that slot
246	 * with the pci_hotplug subsystem.
247	 */
248	for (i = 0; i < num_slots; ++i) {
249		slot = kzalloc(sizeof(*slot), GFP_KERNEL);
250		if (!slot) {
251			retval = -ENOMEM;
252			goto error;
253		}
254
255		hotplug_slot = kzalloc(sizeof(*hotplug_slot), GFP_KERNEL);
256		if (!hotplug_slot) {
257			retval = -ENOMEM;
258			goto error_slot;
259		}
260		slot->hotplug_slot = hotplug_slot;
261
262		info = kzalloc(sizeof(*info), GFP_KERNEL);
263		if (!info) {
264			retval = -ENOMEM;
265			goto error_hpslot;
266		}
267		hotplug_slot->info = info;
268
269		slot->number = i;
270
271		hotplug_slot->name = slot->name;
272		hotplug_slot->private = slot;
273		hotplug_slot->release = &release_slot;
274		make_slot_name(slot);
275		hotplug_slot->ops = &skel_hotplug_slot_ops;
276
277		/*
278		 * Initialize the slot info structure with some known
279		 * good values.
280		 */
281		get_power_status(hotplug_slot, &info->power_status);
282		get_attention_status(hotplug_slot, &info->attention_status);
283		get_latch_status(hotplug_slot, &info->latch_status);
284		get_adapter_status(hotplug_slot, &info->adapter_status);
285
286		dbg("registering slot %d\n", i);
287		retval = pci_hp_register(slot->hotplug_slot);
288		if (retval) {
289			err("pci_hp_register failed with error %d\n", retval);
290			goto error_info;
291		}
292
293		/* add slot to our internal list */
294		list_add(&slot->slot_list, &slot_list);
295	}
296
297	return 0;
298error_info:
299	kfree(info);
300error_hpslot:
301	kfree(hotplug_slot);
302error_slot:
303	kfree(slot);
304error:
305	return retval;
306}
307
308static void __exit cleanup_slots(void)
309{
310	struct slot *slot, *next;
311
312	/*
313	 * Unregister all of our slots with the pci_hotplug subsystem.
314	 * Memory will be freed in release_slot() callback after slot's
315	 * lifespan is finished.
316	 */
317	list_for_each_entry_safe(slot, next, &slot_list, slot_list) {
318		list_del(&slot->slot_list);
319		pci_hp_deregister(slot->hotplug_slot);
320	}
321}
322
323static int __init pcihp_skel_init(void)
324{
325	int retval;
326
327	info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
328	/*
329	 * Do specific initialization stuff for your driver here
330	 * like initializing your controller hardware (if any) and
331	 * determining the number of slots you have in the system
332	 * right now.
333	 */
334	num_slots = 5;
335
336	return init_slots();
337}
338
339static void __exit pcihp_skel_exit(void)
340{
341	/*
342	 * Clean everything up.
343	 */
344	cleanup_slots();
345}
346
347module_init(pcihp_skel_init);
348module_exit(pcihp_skel_exit);