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Linux/arch/powerpc/sysdev/pmi.c

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  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 
 27 struct 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 
 40 static struct pmi_data *data;
 41 
 42 static 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;
 69 unlock:
 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;
 86 out:
 87         return rc;
 88 }
 89 
 90 
 91 static const struct of_device_id pmi_match[] = {
 92         { .type = "ibm,pmi", .name = "ibm,pmi" },
 93         { .type = "ibm,pmi" },
 94         {},
 95 };
 96 
 97 MODULE_DEVICE_TABLE(of, pmi_match);
 98 
 99 static 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 
112 static 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 
165 error_cleanup_iomap:
166         iounmap(data->pmi_reg);
167 
168 error_cleanup_data:
169         kfree(data);
170 
171 out:
172         return rc;
173 }
174 
175 static 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 
195 static 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 };
203 module_platform_driver(pmi_of_platform_driver);
204 
205 int 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 }
238 EXPORT_SYMBOL_GPL(pmi_send_message);
239 
240 int 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 }
251 EXPORT_SYMBOL_GPL(pmi_register_handler);
252 
253 void 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 }
264 EXPORT_SYMBOL_GPL(pmi_unregister_handler);
265 
266 MODULE_LICENSE("GPL");
267 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
268 MODULE_DESCRIPTION("IBM Platform Management Interrupt driver");
269 

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