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/slab.h> 29 #include <linux/completion.h> 30 #include <linux/spinlock.h> 31 #include <linux/workqueue.h> 32 #include <linux/of_device.h> 33 #include <linux/of_platform.h> 34 35 #include <asm/io.h> 36 #include <asm/pmi.h> 37 #include <asm/prom.h> 38 39 struct pmi_data { 40 struct list_head handler; 41 spinlock_t handler_spinlock; 42 spinlock_t pmi_spinlock; 43 struct mutex msg_mutex; 44 pmi_message_t msg; 45 struct completion *completion; 46 struct of_device *dev; 47 int irq; 48 u8 __iomem *pmi_reg; 49 struct work_struct work; 50 }; 51 52 static struct pmi_data *data; 53 54 static irqreturn_t pmi_irq_handler(int irq, void *dev_id) 55 { 56 u8 type; 57 int rc; 58 59 spin_lock(&data->pmi_spinlock); 60 61 type = ioread8(data->pmi_reg + PMI_READ_TYPE); 62 pr_debug("pmi: got message of type %d\n", type); 63 64 if (type & PMI_ACK && !data->completion) { 65 printk(KERN_WARNING "pmi: got unexpected ACK message.\n"); 66 rc = -EIO; 67 goto unlock; 68 } 69 70 if (data->completion && !(type & PMI_ACK)) { 71 printk(KERN_WARNING "pmi: expected ACK, but got %d\n", type); 72 rc = -EIO; 73 goto unlock; 74 } 75 76 data->msg.type = type; 77 data->msg.data0 = ioread8(data->pmi_reg + PMI_READ_DATA0); 78 data->msg.data1 = ioread8(data->pmi_reg + PMI_READ_DATA1); 79 data->msg.data2 = ioread8(data->pmi_reg + PMI_READ_DATA2); 80 rc = 0; 81 unlock: 82 spin_unlock(&data->pmi_spinlock); 83 84 if (rc == -EIO) { 85 rc = IRQ_HANDLED; 86 goto out; 87 } 88 89 if (data->msg.type & PMI_ACK) { 90 complete(data->completion); 91 rc = IRQ_HANDLED; 92 goto out; 93 } 94 95 schedule_work(&data->work); 96 97 rc = IRQ_HANDLED; 98 out: 99 return rc; 100 } 101 102 103 static struct of_device_id pmi_match[] = { 104 { .type = "ibm,pmi", .name = "ibm,pmi" }, 105 { .type = "ibm,pmi" }, 106 {}, 107 }; 108 109 MODULE_DEVICE_TABLE(of, pmi_match); 110 111 static void pmi_notify_handlers(struct work_struct *work) 112 { 113 struct pmi_handler *handler; 114 115 spin_lock(&data->handler_spinlock); 116 list_for_each_entry(handler, &data->handler, node) { 117 pr_debug(KERN_INFO "pmi: notifying handler %p\n", handler); 118 if (handler->type == data->msg.type) 119 handler->handle_pmi_message(data->msg); 120 } 121 spin_unlock(&data->handler_spinlock); 122 } 123 124 static int pmi_of_probe(struct of_device *dev, 125 const struct of_device_id *match) 126 { 127 struct device_node *np = dev->dev.of_node; 128 int rc; 129 130 if (data) { 131 printk(KERN_ERR "pmi: driver has already been initialized.\n"); 132 rc = -EBUSY; 133 goto out; 134 } 135 136 data = kzalloc(sizeof(struct pmi_data), GFP_KERNEL); 137 if (!data) { 138 printk(KERN_ERR "pmi: could not allocate memory.\n"); 139 rc = -ENOMEM; 140 goto out; 141 } 142 143 data->pmi_reg = of_iomap(np, 0); 144 if (!data->pmi_reg) { 145 printk(KERN_ERR "pmi: invalid register address.\n"); 146 rc = -EFAULT; 147 goto error_cleanup_data; 148 } 149 150 INIT_LIST_HEAD(&data->handler); 151 152 mutex_init(&data->msg_mutex); 153 spin_lock_init(&data->pmi_spinlock); 154 spin_lock_init(&data->handler_spinlock); 155 156 INIT_WORK(&data->work, pmi_notify_handlers); 157 158 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", NULL); 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_handler *handler, *tmp; 191 192 free_irq(data->irq, NULL); 193 iounmap(data->pmi_reg); 194 195 spin_lock(&data->handler_spinlock); 196 197 list_for_each_entry_safe(handler, tmp, &data->handler, node) 198 list_del(&handler->node); 199 200 spin_unlock(&data->handler_spinlock); 201 202 kfree(data); 203 data = NULL; 204 205 return 0; 206 } 207 208 static struct of_platform_driver pmi_of_platform_driver = { 209 .match_table = pmi_match, 210 .probe = pmi_of_probe, 211 .remove = pmi_of_remove, 212 .driver = { 213 .name = "pmi", 214 }, 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 int pmi_send_message(pmi_message_t msg) 230 { 231 unsigned long flags; 232 DECLARE_COMPLETION_ONSTACK(completion); 233 234 if (!data) 235 return -ENODEV; 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 return 0; 261 } 262 EXPORT_SYMBOL_GPL(pmi_send_message); 263 264 int pmi_register_handler(struct pmi_handler *handler) 265 { 266 if (!data) 267 return -ENODEV; 268 269 spin_lock(&data->handler_spinlock); 270 list_add_tail(&handler->node, &data->handler); 271 spin_unlock(&data->handler_spinlock); 272 273 return 0; 274 } 275 EXPORT_SYMBOL_GPL(pmi_register_handler); 276 277 void pmi_unregister_handler(struct pmi_handler *handler) 278 { 279 if (!data) 280 return; 281 282 pr_debug("pmi: unregistering handler %p\n", handler); 283 284 spin_lock(&data->handler_spinlock); 285 list_del(&handler->node); 286 spin_unlock(&data->handler_spinlock); 287 } 288 EXPORT_SYMBOL_GPL(pmi_unregister_handler); 289 290 MODULE_LICENSE("GPL"); 291 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>"); 292 MODULE_DESCRIPTION("IBM Platform Management Interrupt driver"); 293