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/module.h> 32 #include <linux/workqueue.h> 33 #include <linux/of_device.h> 34 #include <linux/of_platform.h> 35 36 #include <asm/io.h> 37 #include <asm/pmi.h> 38 #include <asm/prom.h> 39 40 struct pmi_data { 41 struct list_head handler; 42 spinlock_t handler_spinlock; 43 spinlock_t pmi_spinlock; 44 struct mutex msg_mutex; 45 pmi_message_t msg; 46 struct completion *completion; 47 struct platform_device *dev; 48 int irq; 49 u8 __iomem *pmi_reg; 50 struct work_struct work; 51 }; 52 53 static struct pmi_data *data; 54 55 static irqreturn_t pmi_irq_handler(int irq, void *dev_id) 56 { 57 u8 type; 58 int rc; 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_handler *handler; 115 116 spin_lock(&data->handler_spinlock); 117 list_for_each_entry(handler, &data->handler, node) { 118 pr_debug("pmi: notifying handler %p\n", handler); 119 if (handler->type == data->msg.type) 120 handler->handle_pmi_message(data->msg); 121 } 122 spin_unlock(&data->handler_spinlock); 123 } 124 125 static int pmi_of_probe(struct platform_device *dev) 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 platform_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 platform_driver pmi_of_platform_driver = { 209 .probe = pmi_of_probe, 210 .remove = pmi_of_remove, 211 .driver = { 212 .name = "pmi", 213 .owner = THIS_MODULE, 214 .of_match_table = pmi_match, 215 }, 216 }; 217 218 static int __init pmi_module_init(void) 219 { 220 return platform_driver_register(&pmi_of_platform_driver); 221 } 222 module_init(pmi_module_init); 223 224 static void __exit pmi_module_exit(void) 225 { 226 platform_driver_unregister(&pmi_of_platform_driver); 227 } 228 module_exit(pmi_module_exit); 229 230 int pmi_send_message(pmi_message_t msg) 231 { 232 unsigned long flags; 233 DECLARE_COMPLETION_ONSTACK(completion); 234 235 if (!data) 236 return -ENODEV; 237 238 mutex_lock(&data->msg_mutex); 239 240 data->msg = msg; 241 pr_debug("pmi_send_message: msg is %08x\n", *(u32*)&msg); 242 243 data->completion = &completion; 244 245 spin_lock_irqsave(&data->pmi_spinlock, flags); 246 iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0); 247 iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1); 248 iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2); 249 iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE); 250 spin_unlock_irqrestore(&data->pmi_spinlock, flags); 251 252 pr_debug("pmi_send_message: wait for completion\n"); 253 254 wait_for_completion_interruptible_timeout(data->completion, 255 PMI_TIMEOUT); 256 257 data->completion = NULL; 258 259 mutex_unlock(&data->msg_mutex); 260 261 return 0; 262 } 263 EXPORT_SYMBOL_GPL(pmi_send_message); 264 265 int pmi_register_handler(struct pmi_handler *handler) 266 { 267 if (!data) 268 return -ENODEV; 269 270 spin_lock(&data->handler_spinlock); 271 list_add_tail(&handler->node, &data->handler); 272 spin_unlock(&data->handler_spinlock); 273 274 return 0; 275 } 276 EXPORT_SYMBOL_GPL(pmi_register_handler); 277 278 void pmi_unregister_handler(struct pmi_handler *handler) 279 { 280 if (!data) 281 return; 282 283 pr_debug("pmi: unregistering handler %p\n", handler); 284 285 spin_lock(&data->handler_spinlock); 286 list_del(&handler->node); 287 spin_unlock(&data->handler_spinlock); 288 } 289 EXPORT_SYMBOL_GPL(pmi_unregister_handler); 290 291 MODULE_LICENSE("GPL"); 292 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>"); 293 MODULE_DESCRIPTION("IBM Platform Management Interrupt driver"); 294