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 | |
28 | struct 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 | |
41 | static struct pmi_data *data; |
42 | |
43 | static irqreturn_t pmi_irq_handler(int irq, void *dev_id) |
44 | { |
45 | u8 type; |
46 | int rc; |
47 | |
48 | spin_lock(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; |
70 | unlock: |
71 | spin_unlock(lock: &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(work: &data->work); |
85 | |
86 | rc = IRQ_HANDLED; |
87 | out: |
88 | return rc; |
89 | } |
90 | |
91 | |
92 | static const struct of_device_id pmi_match[] = { |
93 | { .type = "ibm,pmi" , .name = "ibm,pmi" }, |
94 | { .type = "ibm,pmi" }, |
95 | {}, |
96 | }; |
97 | |
98 | MODULE_DEVICE_TABLE(of, pmi_match); |
99 | |
100 | static void pmi_notify_handlers(struct work_struct *work) |
101 | { |
102 | struct pmi_handler *handler; |
103 | |
104 | spin_lock(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(lock: &data->handler_spinlock); |
111 | } |
112 | |
113 | static 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(size: 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(node: np, index: 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(list: &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(node: np, index: 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(irq: data->irq, handler: pmi_irq_handler, flags: 0, name: "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 | |
166 | error_cleanup_iomap: |
167 | iounmap(addr: data->pmi_reg); |
168 | |
169 | error_cleanup_data: |
170 | kfree(objp: data); |
171 | |
172 | out: |
173 | return rc; |
174 | } |
175 | |
176 | static void pmi_of_remove(struct platform_device *dev) |
177 | { |
178 | struct pmi_handler *handler, *tmp; |
179 | |
180 | free_irq(data->irq, NULL); |
181 | iounmap(addr: data->pmi_reg); |
182 | |
183 | spin_lock(lock: &data->handler_spinlock); |
184 | |
185 | list_for_each_entry_safe(handler, tmp, &data->handler, node) |
186 | list_del(entry: &handler->node); |
187 | |
188 | spin_unlock(lock: &data->handler_spinlock); |
189 | |
190 | kfree(objp: data); |
191 | data = NULL; |
192 | } |
193 | |
194 | static struct platform_driver pmi_of_platform_driver = { |
195 | .probe = pmi_of_probe, |
196 | .remove_new = pmi_of_remove, |
197 | .driver = { |
198 | .name = "pmi" , |
199 | .of_match_table = pmi_match, |
200 | }, |
201 | }; |
202 | module_platform_driver(pmi_of_platform_driver); |
203 | |
204 | int pmi_send_message(pmi_message_t msg) |
205 | { |
206 | unsigned long flags; |
207 | DECLARE_COMPLETION_ONSTACK(completion); |
208 | |
209 | if (!data) |
210 | return -ENODEV; |
211 | |
212 | mutex_lock(&data->msg_mutex); |
213 | |
214 | data->msg = msg; |
215 | pr_debug("pmi_send_message: msg is %08x\n" , *(u32*)&msg); |
216 | |
217 | data->completion = &completion; |
218 | |
219 | spin_lock_irqsave(&data->pmi_spinlock, flags); |
220 | iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0); |
221 | iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1); |
222 | iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2); |
223 | iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE); |
224 | spin_unlock_irqrestore(lock: &data->pmi_spinlock, flags); |
225 | |
226 | pr_debug("pmi_send_message: wait for completion\n" ); |
227 | |
228 | wait_for_completion_interruptible_timeout(x: data->completion, |
229 | timeout: PMI_TIMEOUT); |
230 | |
231 | data->completion = NULL; |
232 | |
233 | mutex_unlock(lock: &data->msg_mutex); |
234 | |
235 | return 0; |
236 | } |
237 | EXPORT_SYMBOL_GPL(pmi_send_message); |
238 | |
239 | int pmi_register_handler(struct pmi_handler *handler) |
240 | { |
241 | if (!data) |
242 | return -ENODEV; |
243 | |
244 | spin_lock(lock: &data->handler_spinlock); |
245 | list_add_tail(new: &handler->node, head: &data->handler); |
246 | spin_unlock(lock: &data->handler_spinlock); |
247 | |
248 | return 0; |
249 | } |
250 | EXPORT_SYMBOL_GPL(pmi_register_handler); |
251 | |
252 | void pmi_unregister_handler(struct pmi_handler *handler) |
253 | { |
254 | if (!data) |
255 | return; |
256 | |
257 | pr_debug("pmi: unregistering handler %p\n" , handler); |
258 | |
259 | spin_lock(lock: &data->handler_spinlock); |
260 | list_del(entry: &handler->node); |
261 | spin_unlock(lock: &data->handler_spinlock); |
262 | } |
263 | EXPORT_SYMBOL_GPL(pmi_unregister_handler); |
264 | |
265 | MODULE_LICENSE("GPL" ); |
266 | MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>" ); |
267 | MODULE_DESCRIPTION("IBM Platform Management Interrupt driver" ); |
268 | |