1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * pmi driver
  4 *
  5 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
  6 *
  7 * PMI (Platform Management Interrupt) is a way to communicate
  8 * with the BMC (Baseboard Management Controller) via interrupts.
  9 * Unlike IPMI it is bidirectional and has a low latency.
 10 *
 11 * Author: Christian Krafft <krafft@de.ibm.com>
 12 */
 13
 14#include <linux/interrupt.h>
 15#include <linux/slab.h>
 16#include <linux/completion.h>
 17#include <linux/spinlock.h>
 18#include <linux/module.h>
 19#include <linux/mod_devicetable.h>
 20#include <linux/workqueue.h>
 21#include <linux/of_address.h>
 22#include <linux/of_irq.h>
 23#include <linux/platform_device.h>
 24
 25#include <asm/io.h>
 26#include <asm/pmi.h>
 
 27
 28struct pmi_data {
 29	struct list_head	handler;
 30	spinlock_t		handler_spinlock;
 31	spinlock_t		pmi_spinlock;
 32	struct mutex		msg_mutex;
 33	pmi_message_t		msg;
 34	struct completion	*completion;
 35	struct platform_device	*dev;
 36	int			irq;
 37	u8 __iomem		*pmi_reg;
 38	struct work_struct	work;
 39};
 40
 41static struct pmi_data *data;
 42
 43static irqreturn_t pmi_irq_handler(int irq, void *dev_id)
 44{
 45	u8 type;
 46	int rc;
 47
 48	spin_lock(&data->pmi_spinlock);
 49
 50	type = ioread8(data->pmi_reg + PMI_READ_TYPE);
 51	pr_debug("pmi: got message of type %d\n", type);
 52
 53	if (type & PMI_ACK && !data->completion) {
 54		printk(KERN_WARNING "pmi: got unexpected ACK message.\n");
 55		rc = -EIO;
 56		goto unlock;
 57	}
 58
 59	if (data->completion && !(type & PMI_ACK)) {
 60		printk(KERN_WARNING "pmi: expected ACK, but got %d\n", type);
 61		rc = -EIO;
 62		goto unlock;
 63	}
 64
 65	data->msg.type = type;
 66	data->msg.data0 = ioread8(data->pmi_reg + PMI_READ_DATA0);
 67	data->msg.data1 = ioread8(data->pmi_reg + PMI_READ_DATA1);
 68	data->msg.data2 = ioread8(data->pmi_reg + PMI_READ_DATA2);
 69	rc = 0;
 70unlock:
 71	spin_unlock(&data->pmi_spinlock);
 72
 73	if (rc == -EIO) {
 74		rc = IRQ_HANDLED;
 75		goto out;
 76	}
 77
 78	if (data->msg.type & PMI_ACK) {
 79		complete(data->completion);
 80		rc = IRQ_HANDLED;
 81		goto out;
 82	}
 83
 84	schedule_work(&data->work);
 85
 86	rc = IRQ_HANDLED;
 87out:
 88	return rc;
 89}
 90
 91
 92static const struct of_device_id pmi_match[] = {
 93	{ .type = "ibm,pmi", .name = "ibm,pmi" },
 94	{ .type = "ibm,pmi" },
 95	{},
 96};
 97
 98MODULE_DEVICE_TABLE(of, pmi_match);
 99
100static void pmi_notify_handlers(struct work_struct *work)
101{
102	struct pmi_handler *handler;
103
104	spin_lock(&data->handler_spinlock);
105	list_for_each_entry(handler, &data->handler, node) {
106		pr_debug("pmi: notifying handler %p\n", handler);
107		if (handler->type == data->msg.type)
108			handler->handle_pmi_message(data->msg);
109	}
110	spin_unlock(&data->handler_spinlock);
111}
112
113static int pmi_of_probe(struct platform_device *dev)
114{
115	struct device_node *np = dev->dev.of_node;
116	int rc;
117
118	if (data) {
119		printk(KERN_ERR "pmi: driver has already been initialized.\n");
120		rc = -EBUSY;
121		goto out;
122	}
123
124	data = kzalloc(sizeof(struct pmi_data), GFP_KERNEL);
125	if (!data) {
126		printk(KERN_ERR "pmi: could not allocate memory.\n");
127		rc = -ENOMEM;
128		goto out;
129	}
130
131	data->pmi_reg = of_iomap(np, 0);
132	if (!data->pmi_reg) {
133		printk(KERN_ERR "pmi: invalid register address.\n");
134		rc = -EFAULT;
135		goto error_cleanup_data;
136	}
137
138	INIT_LIST_HEAD(&data->handler);
139
140	mutex_init(&data->msg_mutex);
141	spin_lock_init(&data->pmi_spinlock);
142	spin_lock_init(&data->handler_spinlock);
143
144	INIT_WORK(&data->work, pmi_notify_handlers);
145
146	data->dev = dev;
147
148	data->irq = irq_of_parse_and_map(np, 0);
149	if (!data->irq) {
150		printk(KERN_ERR "pmi: invalid interrupt.\n");
151		rc = -EFAULT;
152		goto error_cleanup_iomap;
153	}
154
155	rc = request_irq(data->irq, pmi_irq_handler, 0, "pmi", NULL);
156	if (rc) {
157		printk(KERN_ERR "pmi: can't request IRQ %d: returned %d\n",
158				data->irq, rc);
159		goto error_cleanup_iomap;
160	}
161
162	printk(KERN_INFO "pmi: found pmi device at addr %p.\n", data->pmi_reg);
163
164	goto out;
165
166error_cleanup_iomap:
167	iounmap(data->pmi_reg);
168
169error_cleanup_data:
170	kfree(data);
171
172out:
173	return rc;
174}
175
176static int pmi_of_remove(struct platform_device *dev)
177{
178	struct pmi_handler *handler, *tmp;
179
180	free_irq(data->irq, NULL);
181	iounmap(data->pmi_reg);
182
183	spin_lock(&data->handler_spinlock);
184
185	list_for_each_entry_safe(handler, tmp, &data->handler, node)
186		list_del(&handler->node);
187
188	spin_unlock(&data->handler_spinlock);
189
190	kfree(data);
191	data = NULL;
192
193	return 0;
194}
195
196static struct platform_driver pmi_of_platform_driver = {
197	.probe		= pmi_of_probe,
198	.remove		= pmi_of_remove,
199	.driver = {
200		.name = "pmi",
201		.of_match_table = pmi_match,
202	},
203};
204module_platform_driver(pmi_of_platform_driver);
205
206int pmi_send_message(pmi_message_t msg)
207{
208	unsigned long flags;
209	DECLARE_COMPLETION_ONSTACK(completion);
210
211	if (!data)
212		return -ENODEV;
213
214	mutex_lock(&data->msg_mutex);
215
216	data->msg = msg;
217	pr_debug("pmi_send_message: msg is %08x\n", *(u32*)&msg);
218
219	data->completion = &completion;
220
221	spin_lock_irqsave(&data->pmi_spinlock, flags);
222	iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0);
223	iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1);
224	iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2);
225	iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE);
226	spin_unlock_irqrestore(&data->pmi_spinlock, flags);
227
228	pr_debug("pmi_send_message: wait for completion\n");
229
230	wait_for_completion_interruptible_timeout(data->completion,
231						  PMI_TIMEOUT);
232
233	data->completion = NULL;
234
235	mutex_unlock(&data->msg_mutex);
236
237	return 0;
238}
239EXPORT_SYMBOL_GPL(pmi_send_message);
240
241int pmi_register_handler(struct pmi_handler *handler)
242{
243	if (!data)
244		return -ENODEV;
245
246	spin_lock(&data->handler_spinlock);
247	list_add_tail(&handler->node, &data->handler);
248	spin_unlock(&data->handler_spinlock);
249
250	return 0;
251}
252EXPORT_SYMBOL_GPL(pmi_register_handler);
253
254void pmi_unregister_handler(struct pmi_handler *handler)
255{
256	if (!data)
257		return;
258
259	pr_debug("pmi: unregistering handler %p\n", handler);
260
261	spin_lock(&data->handler_spinlock);
262	list_del(&handler->node);
263	spin_unlock(&data->handler_spinlock);
264}
265EXPORT_SYMBOL_GPL(pmi_unregister_handler);
266
267MODULE_LICENSE("GPL");
268MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
269MODULE_DESCRIPTION("IBM Platform Management Interrupt driver");

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * pmi driver
  4 *
  5 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
  6 *
  7 * PMI (Platform Management Interrupt) is a way to communicate
  8 * with the BMC (Baseboard Management Controller) via interrupts.
  9 * Unlike IPMI it is bidirectional and has a low latency.
 10 *
 11 * Author: Christian Krafft <krafft@de.ibm.com>
 12 */
 13
 14#include <linux/interrupt.h>
 15#include <linux/slab.h>
 16#include <linux/completion.h>
 17#include <linux/spinlock.h>
 18#include <linux/module.h>
 
 19#include <linux/workqueue.h>
 20#include <linux/of_device.h>
 21#include <linux/of_platform.h>
 
 22
 23#include <asm/io.h>
 24#include <asm/pmi.h>
 25#include <asm/prom.h>
 26
 27struct pmi_data {
 28	struct list_head	handler;
 29	spinlock_t		handler_spinlock;
 30	spinlock_t		pmi_spinlock;
 31	struct mutex		msg_mutex;
 32	pmi_message_t		msg;
 33	struct completion	*completion;
 34	struct platform_device	*dev;
 35	int			irq;
 36	u8 __iomem		*pmi_reg;
 37	struct work_struct	work;
 38};
 39
 40static struct pmi_data *data;
 41
 42static irqreturn_t pmi_irq_handler(int irq, void *dev_id)
 43{
 44	u8 type;
 45	int rc;
 46
 47	spin_lock(&data->pmi_spinlock);
 48
 49	type = ioread8(data->pmi_reg + PMI_READ_TYPE);
 50	pr_debug("pmi: got message of type %d\n", type);
 51
 52	if (type & PMI_ACK && !data->completion) {
 53		printk(KERN_WARNING "pmi: got unexpected ACK message.\n");
 54		rc = -EIO;
 55		goto unlock;
 56	}
 57
 58	if (data->completion && !(type & PMI_ACK)) {
 59		printk(KERN_WARNING "pmi: expected ACK, but got %d\n", type);
 60		rc = -EIO;
 61		goto unlock;
 62	}
 63
 64	data->msg.type = type;
 65	data->msg.data0 = ioread8(data->pmi_reg + PMI_READ_DATA0);
 66	data->msg.data1 = ioread8(data->pmi_reg + PMI_READ_DATA1);
 67	data->msg.data2 = ioread8(data->pmi_reg + PMI_READ_DATA2);
 68	rc = 0;
 69unlock:
 70	spin_unlock(&data->pmi_spinlock);
 71
 72	if (rc == -EIO) {
 73		rc = IRQ_HANDLED;
 74		goto out;
 75	}
 76
 77	if (data->msg.type & PMI_ACK) {
 78		complete(data->completion);
 79		rc = IRQ_HANDLED;
 80		goto out;
 81	}
 82
 83	schedule_work(&data->work);
 84
 85	rc = IRQ_HANDLED;
 86out:
 87	return rc;
 88}
 89
 90
 91static const struct of_device_id pmi_match[] = {
 92	{ .type = "ibm,pmi", .name = "ibm,pmi" },
 93	{ .type = "ibm,pmi" },
 94	{},
 95};
 96
 97MODULE_DEVICE_TABLE(of, pmi_match);
 98
 99static void pmi_notify_handlers(struct work_struct *work)
100{
101	struct pmi_handler *handler;
102
103	spin_lock(&data->handler_spinlock);
104	list_for_each_entry(handler, &data->handler, node) {
105		pr_debug("pmi: notifying handler %p\n", handler);
106		if (handler->type == data->msg.type)
107			handler->handle_pmi_message(data->msg);
108	}
109	spin_unlock(&data->handler_spinlock);
110}
111
112static int pmi_of_probe(struct platform_device *dev)
113{
114	struct device_node *np = dev->dev.of_node;
115	int rc;
116
117	if (data) {
118		printk(KERN_ERR "pmi: driver has already been initialized.\n");
119		rc = -EBUSY;
120		goto out;
121	}
122
123	data = kzalloc(sizeof(struct pmi_data), GFP_KERNEL);
124	if (!data) {
125		printk(KERN_ERR "pmi: could not allocate memory.\n");
126		rc = -ENOMEM;
127		goto out;
128	}
129
130	data->pmi_reg = of_iomap(np, 0);
131	if (!data->pmi_reg) {
132		printk(KERN_ERR "pmi: invalid register address.\n");
133		rc = -EFAULT;
134		goto error_cleanup_data;
135	}
136
137	INIT_LIST_HEAD(&data->handler);
138
139	mutex_init(&data->msg_mutex);
140	spin_lock_init(&data->pmi_spinlock);
141	spin_lock_init(&data->handler_spinlock);
142
143	INIT_WORK(&data->work, pmi_notify_handlers);
144
145	data->dev = dev;
146
147	data->irq = irq_of_parse_and_map(np, 0);
148	if (!data->irq) {
149		printk(KERN_ERR "pmi: invalid interrupt.\n");
150		rc = -EFAULT;
151		goto error_cleanup_iomap;
152	}
153
154	rc = request_irq(data->irq, pmi_irq_handler, 0, "pmi", NULL);
155	if (rc) {
156		printk(KERN_ERR "pmi: can't request IRQ %d: returned %d\n",
157				data->irq, rc);
158		goto error_cleanup_iomap;
159	}
160
161	printk(KERN_INFO "pmi: found pmi device at addr %p.\n", data->pmi_reg);
162
163	goto out;
164
165error_cleanup_iomap:
166	iounmap(data->pmi_reg);
167
168error_cleanup_data:
169	kfree(data);
170
171out:
172	return rc;
173}
174
175static int pmi_of_remove(struct platform_device *dev)
176{
177	struct pmi_handler *handler, *tmp;
178
179	free_irq(data->irq, NULL);
180	iounmap(data->pmi_reg);
181
182	spin_lock(&data->handler_spinlock);
183
184	list_for_each_entry_safe(handler, tmp, &data->handler, node)
185		list_del(&handler->node);
186
187	spin_unlock(&data->handler_spinlock);
188
189	kfree(data);
190	data = NULL;
191
192	return 0;
193}
194
195static struct platform_driver pmi_of_platform_driver = {
196	.probe		= pmi_of_probe,
197	.remove		= pmi_of_remove,
198	.driver = {
199		.name = "pmi",
200		.of_match_table = pmi_match,
201	},
202};
203module_platform_driver(pmi_of_platform_driver);
204
205int pmi_send_message(pmi_message_t msg)
206{
207	unsigned long flags;
208	DECLARE_COMPLETION_ONSTACK(completion);
209
210	if (!data)
211		return -ENODEV;
212
213	mutex_lock(&data->msg_mutex);
214
215	data->msg = msg;
216	pr_debug("pmi_send_message: msg is %08x\n", *(u32*)&msg);
217
218	data->completion = &completion;
219
220	spin_lock_irqsave(&data->pmi_spinlock, flags);
221	iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0);
222	iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1);
223	iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2);
224	iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE);
225	spin_unlock_irqrestore(&data->pmi_spinlock, flags);
226
227	pr_debug("pmi_send_message: wait for completion\n");
228
229	wait_for_completion_interruptible_timeout(data->completion,
230						  PMI_TIMEOUT);
231
232	data->completion = NULL;
233
234	mutex_unlock(&data->msg_mutex);
235
236	return 0;
237}
238EXPORT_SYMBOL_GPL(pmi_send_message);
239
240int pmi_register_handler(struct pmi_handler *handler)
241{
242	if (!data)
243		return -ENODEV;
244
245	spin_lock(&data->handler_spinlock);
246	list_add_tail(&handler->node, &data->handler);
247	spin_unlock(&data->handler_spinlock);
248
249	return 0;
250}
251EXPORT_SYMBOL_GPL(pmi_register_handler);
252
253void pmi_unregister_handler(struct pmi_handler *handler)
254{
255	if (!data)
256		return;
257
258	pr_debug("pmi: unregistering handler %p\n", handler);
259
260	spin_lock(&data->handler_spinlock);
261	list_del(&handler->node);
262	spin_unlock(&data->handler_spinlock);
263}
264EXPORT_SYMBOL_GPL(pmi_unregister_handler);
265
266MODULE_LICENSE("GPL");
267MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
268MODULE_DESCRIPTION("IBM Platform Management Interrupt driver");