1 /* 2 * pmi driver 3 * 4 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005 5 * 6 * PMI (Platform Management Interrupt) is a way to communicate 7 * with the BMC (Baseboard Management Controller) via interrupts. 8 * Unlike IPMI it is bidirectional and has a low latency. 9 * 10 * Author: Christian Krafft <krafft@de.ibm.com> 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License as published by 14 * the Free Software Foundation; either version 2, or (at your option) 15 * any later version. 16 * 17 * This program is distributed in the hope that it will be useful, 18 * but WITHOUT ANY WARRANTY; without even the implied warranty of 19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 20 * GNU General Public License for more details. 21 * 22 * You should have received a copy of the GNU General Public License 23 * along with this program; if not, write to the Free Software 24 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 25 */ 26 27 #include <linux/interrupt.h> 28 #include <linux/completion.h> 29 #include <linux/spinlock.h> 30 #include <linux/workqueue.h> 31 32 #include <asm/of_device.h> 33 #include <asm/of_platform.h> 34 #include <asm/io.h> 35 #include <asm/pmi.h> 36 #include <asm/prom.h> 37 38 struct pmi_data { 39 struct list_head handler; 40 spinlock_t handler_spinlock; 41 spinlock_t pmi_spinlock; 42 struct mutex msg_mutex; 43 pmi_message_t msg; 44 struct completion *completion; 45 struct of_device *dev; 46 int irq; 47 u8 __iomem *pmi_reg; 48 struct work_struct work; 49 }; 50 51 52 static int pmi_irq_handler(int irq, void *dev_id) 53 { 54 struct pmi_data *data; 55 u8 type; 56 int rc; 57 58 data = dev_id; 59 60 spin_lock(&data->pmi_spinlock); 61 62 type = ioread8(data->pmi_reg + PMI_READ_TYPE); 63 pr_debug("pmi: got message of type %d\n", type); 64 65 if (type & PMI_ACK && !data->completion) { 66 printk(KERN_WARNING "pmi: got unexpected ACK message.\n"); 67 rc = -EIO; 68 goto unlock; 69 } 70 71 if (data->completion && !(type & PMI_ACK)) { 72 printk(KERN_WARNING "pmi: expected ACK, but got %d\n", type); 73 rc = -EIO; 74 goto unlock; 75 } 76 77 data->msg.type = type; 78 data->msg.data0 = ioread8(data->pmi_reg + PMI_READ_DATA0); 79 data->msg.data1 = ioread8(data->pmi_reg + PMI_READ_DATA1); 80 data->msg.data2 = ioread8(data->pmi_reg + PMI_READ_DATA2); 81 rc = 0; 82 unlock: 83 spin_unlock(&data->pmi_spinlock); 84 85 if (rc == -EIO) { 86 rc = IRQ_HANDLED; 87 goto out; 88 } 89 90 if (data->msg.type & PMI_ACK) { 91 complete(data->completion); 92 rc = IRQ_HANDLED; 93 goto out; 94 } 95 96 schedule_work(&data->work); 97 98 rc = IRQ_HANDLED; 99 out: 100 return rc; 101 } 102 103 104 static struct of_device_id pmi_match[] = { 105 { .type = "ibm,pmi", .name = "ibm,pmi" }, 106 { .type = "ibm,pmi" }, 107 {}, 108 }; 109 110 MODULE_DEVICE_TABLE(of, pmi_match); 111 112 static void pmi_notify_handlers(struct work_struct *work) 113 { 114 struct pmi_data *data; 115 struct pmi_handler *handler; 116 117 data = container_of(work, struct pmi_data, work); 118 119 spin_lock(&data->handler_spinlock); 120 list_for_each_entry(handler, &data->handler, node) { 121 pr_debug(KERN_INFO "pmi: notifying handler %p\n", handler); 122 if (handler->type == data->msg.type) 123 handler->handle_pmi_message(data->dev, data->msg); 124 } 125 spin_unlock(&data->handler_spinlock); 126 } 127 128 static int pmi_of_probe(struct of_device *dev, 129 const struct of_device_id *match) 130 { 131 struct device_node *np = dev->node; 132 struct pmi_data *data; 133 int rc; 134 135 data = kzalloc(sizeof(struct pmi_data), GFP_KERNEL); 136 if (!data) { 137 printk(KERN_ERR "pmi: could not allocate memory.\n"); 138 rc = -ENOMEM; 139 goto out; 140 } 141 142 data->pmi_reg = of_iomap(np, 0); 143 if (!data->pmi_reg) { 144 printk(KERN_ERR "pmi: invalid register address.\n"); 145 rc = -EFAULT; 146 goto error_cleanup_data; 147 } 148 149 INIT_LIST_HEAD(&data->handler); 150 151 mutex_init(&data->msg_mutex); 152 spin_lock_init(&data->pmi_spinlock); 153 spin_lock_init(&data->handler_spinlock); 154 155 INIT_WORK(&data->work, pmi_notify_handlers); 156 157 dev->dev.driver_data = data; 158 data->dev = dev; 159 160 data->irq = irq_of_parse_and_map(np, 0); 161 if (data->irq == NO_IRQ) { 162 printk(KERN_ERR "pmi: invalid interrupt.\n"); 163 rc = -EFAULT; 164 goto error_cleanup_iomap; 165 } 166 167 rc = request_irq(data->irq, pmi_irq_handler, 0, "pmi", data); 168 if (rc) { 169 printk(KERN_ERR "pmi: can't request IRQ %d: returned %d\n", 170 data->irq, rc); 171 goto error_cleanup_iomap; 172 } 173 174 printk(KERN_INFO "pmi: found pmi device at addr %p.\n", data->pmi_reg); 175 176 goto out; 177 178 error_cleanup_iomap: 179 iounmap(data->pmi_reg); 180 181 error_cleanup_data: 182 kfree(data); 183 184 out: 185 return rc; 186 } 187 188 static int pmi_of_remove(struct of_device *dev) 189 { 190 struct pmi_data *data; 191 struct pmi_handler *handler, *tmp; 192 193 data = dev->dev.driver_data; 194 195 free_irq(data->irq, data); 196 iounmap(data->pmi_reg); 197 198 spin_lock(&data->handler_spinlock); 199 200 list_for_each_entry_safe(handler, tmp, &data->handler, node) 201 list_del(&handler->node); 202 203 spin_unlock(&data->handler_spinlock); 204 205 kfree(dev->dev.driver_data); 206 207 return 0; 208 } 209 210 static struct of_platform_driver pmi_of_platform_driver = { 211 .name = "pmi", 212 .match_table = pmi_match, 213 .probe = pmi_of_probe, 214 .remove = pmi_of_remove 215 }; 216 217 static int __init pmi_module_init(void) 218 { 219 return of_register_platform_driver(&pmi_of_platform_driver); 220 } 221 module_init(pmi_module_init); 222 223 static void __exit pmi_module_exit(void) 224 { 225 of_unregister_platform_driver(&pmi_of_platform_driver); 226 } 227 module_exit(pmi_module_exit); 228 229 void pmi_send_message(struct of_device *device, pmi_message_t msg) 230 { 231 struct pmi_data *data; 232 unsigned long flags; 233 DECLARE_COMPLETION_ONSTACK(completion); 234 235 data = device->dev.driver_data; 236 237 mutex_lock(&data->msg_mutex); 238 239 data->msg = msg; 240 pr_debug("pmi_send_message: msg is %08x\n", *(u32*)&msg); 241 242 data->completion = &completion; 243 244 spin_lock_irqsave(&data->pmi_spinlock, flags); 245 iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0); 246 iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1); 247 iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2); 248 iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE); 249 spin_unlock_irqrestore(&data->pmi_spinlock, flags); 250 251 pr_debug("pmi_send_message: wait for completion\n"); 252 253 wait_for_completion_interruptible_timeout(data->completion, 254 PMI_TIMEOUT); 255 256 data->completion = NULL; 257 258 mutex_unlock(&data->msg_mutex); 259 } 260 EXPORT_SYMBOL_GPL(pmi_send_message); 261 262 void pmi_register_handler(struct of_device *device, 263 struct pmi_handler *handler) 264 { 265 struct pmi_data *data; 266 data = device->dev.driver_data; 267 268 if (!data) 269 return; 270 271 spin_lock(&data->handler_spinlock); 272 list_add_tail(&handler->node, &data->handler); 273 spin_unlock(&data->handler_spinlock); 274 } 275 EXPORT_SYMBOL_GPL(pmi_register_handler); 276 277 void pmi_unregister_handler(struct of_device *device, 278 struct pmi_handler *handler) 279 { 280 struct pmi_data *data; 281 data = device->dev.driver_data; 282 283 if (!data) 284 return; 285 286 pr_debug("pmi: unregistering handler %p\n", handler); 287 288 spin_lock(&data->handler_spinlock); 289 list_del(&handler->node); 290 spin_unlock(&data->handler_spinlock); 291 } 292 EXPORT_SYMBOL_GPL(pmi_unregister_handler); 293 294 MODULE_LICENSE("GPL"); 295 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>"); 296 MODULE_DESCRIPTION("IBM Platform Management Interrupt driver"); 297