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 #include <linux/of_device.h> 32 #include <linux/of_platform.h> 33 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 static struct pmi_data *data; 52 53 static int pmi_irq_handler(int irq, void *dev_id) 54 { 55 u8 type; 56 int rc; 57 58 spin_lock(&data->pmi_spinlock); 59 60 type = ioread8(data->pmi_reg + PMI_READ_TYPE); 61 pr_debug("pmi: got message of type %d\n", type); 62 63 if (type & PMI_ACK && !data->completion) { 64 printk(KERN_WARNING "pmi: got unexpected ACK message.\n"); 65 rc = -EIO; 66 goto unlock; 67 } 68 69 if (data->completion && !(type & PMI_ACK)) { 70 printk(KERN_WARNING "pmi: expected ACK, but got %d\n", type); 71 rc = -EIO; 72 goto unlock; 73 } 74 75 data->msg.type = type; 76 data->msg.data0 = ioread8(data->pmi_reg + PMI_READ_DATA0); 77 data->msg.data1 = ioread8(data->pmi_reg + PMI_READ_DATA1); 78 data->msg.data2 = ioread8(data->pmi_reg + PMI_READ_DATA2); 79 rc = 0; 80 unlock: 81 spin_unlock(&data->pmi_spinlock); 82 83 if (rc == -EIO) { 84 rc = IRQ_HANDLED; 85 goto out; 86 } 87 88 if (data->msg.type & PMI_ACK) { 89 complete(data->completion); 90 rc = IRQ_HANDLED; 91 goto out; 92 } 93 94 schedule_work(&data->work); 95 96 rc = IRQ_HANDLED; 97 out: 98 return rc; 99 } 100 101 102 static struct of_device_id pmi_match[] = { 103 { .type = "ibm,pmi", .name = "ibm,pmi" }, 104 { .type = "ibm,pmi" }, 105 {}, 106 }; 107 108 MODULE_DEVICE_TABLE(of, pmi_match); 109 110 static void pmi_notify_handlers(struct work_struct *work) 111 { 112 struct pmi_handler *handler; 113 114 spin_lock(&data->handler_spinlock); 115 list_for_each_entry(handler, &data->handler, node) { 116 pr_debug(KERN_INFO "pmi: notifying handler %p\n", handler); 117 if (handler->type == data->msg.type) 118 handler->handle_pmi_message(data->msg); 119 } 120 spin_unlock(&data->handler_spinlock); 121 } 122 123 static int pmi_of_probe(struct of_device *dev, 124 const struct of_device_id *match) 125 { 126 struct device_node *np = dev->node; 127 int rc; 128 129 if (data) { 130 printk(KERN_ERR "pmi: driver has already been initialized.\n"); 131 rc = -EBUSY; 132 goto out; 133 } 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 data->dev = dev; 158 159 data->irq = irq_of_parse_and_map(np, 0); 160 if (data->irq == NO_IRQ) { 161 printk(KERN_ERR "pmi: invalid interrupt.\n"); 162 rc = -EFAULT; 163 goto error_cleanup_iomap; 164 } 165 166 rc = request_irq(data->irq, pmi_irq_handler, 0, "pmi", NULL); 167 if (rc) { 168 printk(KERN_ERR "pmi: can't request IRQ %d: returned %d\n", 169 data->irq, rc); 170 goto error_cleanup_iomap; 171 } 172 173 printk(KERN_INFO "pmi: found pmi device at addr %p.\n", data->pmi_reg); 174 175 goto out; 176 177 error_cleanup_iomap: 178 iounmap(data->pmi_reg); 179 180 error_cleanup_data: 181 kfree(data); 182 183 out: 184 return rc; 185 } 186 187 static int pmi_of_remove(struct of_device *dev) 188 { 189 struct pmi_handler *handler, *tmp; 190 191 free_irq(data->irq, NULL); 192 iounmap(data->pmi_reg); 193 194 spin_lock(&data->handler_spinlock); 195 196 list_for_each_entry_safe(handler, tmp, &data->handler, node) 197 list_del(&handler->node); 198 199 spin_unlock(&data->handler_spinlock); 200 201 kfree(data); 202 data = NULL; 203 204 return 0; 205 } 206 207 static struct of_platform_driver pmi_of_platform_driver = { 208 .match_table = pmi_match, 209 .probe = pmi_of_probe, 210 .remove = pmi_of_remove, 211 .driver = { 212 .name = "pmi", 213 }, 214 }; 215 216 static int __init pmi_module_init(void) 217 { 218 return of_register_platform_driver(&pmi_of_platform_driver); 219 } 220 module_init(pmi_module_init); 221 222 static void __exit pmi_module_exit(void) 223 { 224 of_unregister_platform_driver(&pmi_of_platform_driver); 225 } 226 module_exit(pmi_module_exit); 227 228 int pmi_send_message(pmi_message_t msg) 229 { 230 unsigned long flags; 231 DECLARE_COMPLETION_ONSTACK(completion); 232 233 if (!data) 234 return -ENODEV; 235 236 mutex_lock(&data->msg_mutex); 237 238 data->msg = msg; 239 pr_debug("pmi_send_message: msg is %08x\n", *(u32*)&msg); 240 241 data->completion = &completion; 242 243 spin_lock_irqsave(&data->pmi_spinlock, flags); 244 iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0); 245 iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1); 246 iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2); 247 iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE); 248 spin_unlock_irqrestore(&data->pmi_spinlock, flags); 249 250 pr_debug("pmi_send_message: wait for completion\n"); 251 252 wait_for_completion_interruptible_timeout(data->completion, 253 PMI_TIMEOUT); 254 255 data->completion = NULL; 256 257 mutex_unlock(&data->msg_mutex); 258 259 return 0; 260 } 261 EXPORT_SYMBOL_GPL(pmi_send_message); 262 263 int pmi_register_handler(struct pmi_handler *handler) 264 { 265 if (!data) 266 return -ENODEV; 267 268 spin_lock(&data->handler_spinlock); 269 list_add_tail(&handler->node, &data->handler); 270 spin_unlock(&data->handler_spinlock); 271 272 return 0; 273 } 274 EXPORT_SYMBOL_GPL(pmi_register_handler); 275 276 void pmi_unregister_handler(struct pmi_handler *handler) 277 { 278 if (!data) 279 return; 280 281 pr_debug("pmi: unregistering handler %p\n", handler); 282 283 spin_lock(&data->handler_spinlock); 284 list_del(&handler->node); 285 spin_unlock(&data->handler_spinlock); 286 } 287 EXPORT_SYMBOL_GPL(pmi_unregister_handler); 288 289 MODULE_LICENSE("GPL"); 290 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>"); 291 MODULE_DESCRIPTION("IBM Platform Management Interrupt driver"); 292