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/workqueue.h> 20 #include <linux/of_device.h> 21 #include <linux/of_platform.h> 22 23 #include <asm/io.h> 24 #include <asm/pmi.h> 25 #include <asm/prom.h> 26 27 struct pmi_data { 28 struct list_head handler; 29 spinlock_t handler_spinlock; 30 spinlock_t pmi_spinlock; 31 struct mutex msg_mutex; 32 pmi_message_t msg; 33 struct completion *completion; 34 struct platform_device *dev; 35 int irq; 36 u8 __iomem *pmi_reg; 37 struct work_struct work; 38 }; 39 40 static struct pmi_data *data; 41 42 static irqreturn_t pmi_irq_handler(int irq, void *dev_id) 43 { 44 u8 type; 45 int rc; 46 47 spin_lock(&data->pmi_spinlock); 48 49 type = ioread8(data->pmi_reg + PMI_READ_TYPE); 50 pr_debug("pmi: got message of type %d\n", type); 51 52 if (type & PMI_ACK && !data->completion) { 53 printk(KERN_WARNING "pmi: got unexpected ACK message.\n"); 54 rc = -EIO; 55 goto unlock; 56 } 57 58 if (data->completion && !(type & PMI_ACK)) { 59 printk(KERN_WARNING "pmi: expected ACK, but got %d\n", type); 60 rc = -EIO; 61 goto unlock; 62 } 63 64 data->msg.type = type; 65 data->msg.data0 = ioread8(data->pmi_reg + PMI_READ_DATA0); 66 data->msg.data1 = ioread8(data->pmi_reg + PMI_READ_DATA1); 67 data->msg.data2 = ioread8(data->pmi_reg + PMI_READ_DATA2); 68 rc = 0; 69 unlock: 70 spin_unlock(&data->pmi_spinlock); 71 72 if (rc == -EIO) { 73 rc = IRQ_HANDLED; 74 goto out; 75 } 76 77 if (data->msg.type & PMI_ACK) { 78 complete(data->completion); 79 rc = IRQ_HANDLED; 80 goto out; 81 } 82 83 schedule_work(&data->work); 84 85 rc = IRQ_HANDLED; 86 out: 87 return rc; 88 } 89 90 91 static const struct of_device_id pmi_match[] = { 92 { .type = "ibm,pmi", .name = "ibm,pmi" }, 93 { .type = "ibm,pmi" }, 94 {}, 95 }; 96 97 MODULE_DEVICE_TABLE(of, pmi_match); 98 99 static void pmi_notify_handlers(struct work_struct *work) 100 { 101 struct pmi_handler *handler; 102 103 spin_lock(&data->handler_spinlock); 104 list_for_each_entry(handler, &data->handler, node) { 105 pr_debug("pmi: notifying handler %p\n", handler); 106 if (handler->type == data->msg.type) 107 handler->handle_pmi_message(data->msg); 108 } 109 spin_unlock(&data->handler_spinlock); 110 } 111 112 static int pmi_of_probe(struct platform_device *dev) 113 { 114 struct device_node *np = dev->dev.of_node; 115 int rc; 116 117 if (data) { 118 printk(KERN_ERR "pmi: driver has already been initialized.\n"); 119 rc = -EBUSY; 120 goto out; 121 } 122 123 data = kzalloc(sizeof(struct pmi_data), GFP_KERNEL); 124 if (!data) { 125 printk(KERN_ERR "pmi: could not allocate memory.\n"); 126 rc = -ENOMEM; 127 goto out; 128 } 129 130 data->pmi_reg = of_iomap(np, 0); 131 if (!data->pmi_reg) { 132 printk(KERN_ERR "pmi: invalid register address.\n"); 133 rc = -EFAULT; 134 goto error_cleanup_data; 135 } 136 137 INIT_LIST_HEAD(&data->handler); 138 139 mutex_init(&data->msg_mutex); 140 spin_lock_init(&data->pmi_spinlock); 141 spin_lock_init(&data->handler_spinlock); 142 143 INIT_WORK(&data->work, pmi_notify_handlers); 144 145 data->dev = dev; 146 147 data->irq = irq_of_parse_and_map(np, 0); 148 if (!data->irq) { 149 printk(KERN_ERR "pmi: invalid interrupt.\n"); 150 rc = -EFAULT; 151 goto error_cleanup_iomap; 152 } 153 154 rc = request_irq(data->irq, pmi_irq_handler, 0, "pmi", NULL); 155 if (rc) { 156 printk(KERN_ERR "pmi: can't request IRQ %d: returned %d\n", 157 data->irq, rc); 158 goto error_cleanup_iomap; 159 } 160 161 printk(KERN_INFO "pmi: found pmi device at addr %p.\n", data->pmi_reg); 162 163 goto out; 164 165 error_cleanup_iomap: 166 iounmap(data->pmi_reg); 167 168 error_cleanup_data: 169 kfree(data); 170 171 out: 172 return rc; 173 } 174 175 static int pmi_of_remove(struct platform_device *dev) 176 { 177 struct pmi_handler *handler, *tmp; 178 179 free_irq(data->irq, NULL); 180 iounmap(data->pmi_reg); 181 182 spin_lock(&data->handler_spinlock); 183 184 list_for_each_entry_safe(handler, tmp, &data->handler, node) 185 list_del(&handler->node); 186 187 spin_unlock(&data->handler_spinlock); 188 189 kfree(data); 190 data = NULL; 191 192 return 0; 193 } 194 195 static struct platform_driver pmi_of_platform_driver = { 196 .probe = pmi_of_probe, 197 .remove = pmi_of_remove, 198 .driver = { 199 .name = "pmi", 200 .of_match_table = pmi_match, 201 }, 202 }; 203 module_platform_driver(pmi_of_platform_driver); 204 205 int pmi_send_message(pmi_message_t msg) 206 { 207 unsigned long flags; 208 DECLARE_COMPLETION_ONSTACK(completion); 209 210 if (!data) 211 return -ENODEV; 212 213 mutex_lock(&data->msg_mutex); 214 215 data->msg = msg; 216 pr_debug("pmi_send_message: msg is %08x\n", *(u32*)&msg); 217 218 data->completion = &completion; 219 220 spin_lock_irqsave(&data->pmi_spinlock, flags); 221 iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0); 222 iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1); 223 iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2); 224 iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE); 225 spin_unlock_irqrestore(&data->pmi_spinlock, flags); 226 227 pr_debug("pmi_send_message: wait for completion\n"); 228 229 wait_for_completion_interruptible_timeout(data->completion, 230 PMI_TIMEOUT); 231 232 data->completion = NULL; 233 234 mutex_unlock(&data->msg_mutex); 235 236 return 0; 237 } 238 EXPORT_SYMBOL_GPL(pmi_send_message); 239 240 int pmi_register_handler(struct pmi_handler *handler) 241 { 242 if (!data) 243 return -ENODEV; 244 245 spin_lock(&data->handler_spinlock); 246 list_add_tail(&handler->node, &data->handler); 247 spin_unlock(&data->handler_spinlock); 248 249 return 0; 250 } 251 EXPORT_SYMBOL_GPL(pmi_register_handler); 252 253 void pmi_unregister_handler(struct pmi_handler *handler) 254 { 255 if (!data) 256 return; 257 258 pr_debug("pmi: unregistering handler %p\n", handler); 259 260 spin_lock(&data->handler_spinlock); 261 list_del(&handler->node); 262 spin_unlock(&data->handler_spinlock); 263 } 264 EXPORT_SYMBOL_GPL(pmi_unregister_handler); 265 266 MODULE_LICENSE("GPL"); 267 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>"); 268 MODULE_DESCRIPTION("IBM Platform Management Interrupt driver"); 269