| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * pmi driver |
| * |
| * (C) Copyright IBM Deutschland Entwicklung GmbH 2005 |
| * |
| * PMI (Platform Management Interrupt) is a way to communicate |
| * with the BMC (Baseboard Management Controller) via interrupts. |
| * Unlike IPMI it is bidirectional and has a low latency. |
| * |
| * Author: Christian Krafft <krafft@de.ibm.com> |
| */ |
| |
| #include <linux/interrupt.h> |
| #include <linux/slab.h> |
| #include <linux/completion.h> |
| #include <linux/spinlock.h> |
| #include <linux/module.h> |
| #include <linux/workqueue.h> |
| #include <linux/of_address.h> |
| #include <linux/of_device.h> |
| #include <linux/of_irq.h> |
| #include <linux/of_platform.h> |
| |
| #include <asm/io.h> |
| #include <asm/pmi.h> |
| |
| struct pmi_data { |
| struct list_head handler; |
| spinlock_t handler_spinlock; |
| spinlock_t pmi_spinlock; |
| struct mutex msg_mutex; |
| pmi_message_t msg; |
| struct completion *completion; |
| struct platform_device *dev; |
| int irq; |
| u8 __iomem *pmi_reg; |
| struct work_struct work; |
| }; |
| |
| static struct pmi_data *data; |
| |
| static irqreturn_t pmi_irq_handler(int irq, void *dev_id) |
| { |
| u8 type; |
| int rc; |
| |
| spin_lock(&data->pmi_spinlock); |
| |
| type = ioread8(data->pmi_reg + PMI_READ_TYPE); |
| pr_debug("pmi: got message of type %d\n", type); |
| |
| if (type & PMI_ACK && !data->completion) { |
| printk(KERN_WARNING "pmi: got unexpected ACK message.\n"); |
| rc = -EIO; |
| goto unlock; |
| } |
| |
| if (data->completion && !(type & PMI_ACK)) { |
| printk(KERN_WARNING "pmi: expected ACK, but got %d\n", type); |
| rc = -EIO; |
| goto unlock; |
| } |
| |
| data->msg.type = type; |
| data->msg.data0 = ioread8(data->pmi_reg + PMI_READ_DATA0); |
| data->msg.data1 = ioread8(data->pmi_reg + PMI_READ_DATA1); |
| data->msg.data2 = ioread8(data->pmi_reg + PMI_READ_DATA2); |
| rc = 0; |
| unlock: |
| spin_unlock(&data->pmi_spinlock); |
| |
| if (rc == -EIO) { |
| rc = IRQ_HANDLED; |
| goto out; |
| } |
| |
| if (data->msg.type & PMI_ACK) { |
| complete(data->completion); |
| rc = IRQ_HANDLED; |
| goto out; |
| } |
| |
| schedule_work(&data->work); |
| |
| rc = IRQ_HANDLED; |
| out: |
| return rc; |
| } |
| |
| |
| static const struct of_device_id pmi_match[] = { |
| { .type = "ibm,pmi", .name = "ibm,pmi" }, |
| { .type = "ibm,pmi" }, |
| {}, |
| }; |
| |
| MODULE_DEVICE_TABLE(of, pmi_match); |
| |
| static void pmi_notify_handlers(struct work_struct *work) |
| { |
| struct pmi_handler *handler; |
| |
| spin_lock(&data->handler_spinlock); |
| list_for_each_entry(handler, &data->handler, node) { |
| pr_debug("pmi: notifying handler %p\n", handler); |
| if (handler->type == data->msg.type) |
| handler->handle_pmi_message(data->msg); |
| } |
| spin_unlock(&data->handler_spinlock); |
| } |
| |
| static int pmi_of_probe(struct platform_device *dev) |
| { |
| struct device_node *np = dev->dev.of_node; |
| int rc; |
| |
| if (data) { |
| printk(KERN_ERR "pmi: driver has already been initialized.\n"); |
| rc = -EBUSY; |
| goto out; |
| } |
| |
| data = kzalloc(sizeof(struct pmi_data), GFP_KERNEL); |
| if (!data) { |
| printk(KERN_ERR "pmi: could not allocate memory.\n"); |
| rc = -ENOMEM; |
| goto out; |
| } |
| |
| data->pmi_reg = of_iomap(np, 0); |
| if (!data->pmi_reg) { |
| printk(KERN_ERR "pmi: invalid register address.\n"); |
| rc = -EFAULT; |
| goto error_cleanup_data; |
| } |
| |
| INIT_LIST_HEAD(&data->handler); |
| |
| mutex_init(&data->msg_mutex); |
| spin_lock_init(&data->pmi_spinlock); |
| spin_lock_init(&data->handler_spinlock); |
| |
| INIT_WORK(&data->work, pmi_notify_handlers); |
| |
| data->dev = dev; |
| |
| data->irq = irq_of_parse_and_map(np, 0); |
| if (!data->irq) { |
| printk(KERN_ERR "pmi: invalid interrupt.\n"); |
| rc = -EFAULT; |
| goto error_cleanup_iomap; |
| } |
| |
| rc = request_irq(data->irq, pmi_irq_handler, 0, "pmi", NULL); |
| if (rc) { |
| printk(KERN_ERR "pmi: can't request IRQ %d: returned %d\n", |
| data->irq, rc); |
| goto error_cleanup_iomap; |
| } |
| |
| printk(KERN_INFO "pmi: found pmi device at addr %p.\n", data->pmi_reg); |
| |
| goto out; |
| |
| error_cleanup_iomap: |
| iounmap(data->pmi_reg); |
| |
| error_cleanup_data: |
| kfree(data); |
| |
| out: |
| return rc; |
| } |
| |
| static int pmi_of_remove(struct platform_device *dev) |
| { |
| struct pmi_handler *handler, *tmp; |
| |
| free_irq(data->irq, NULL); |
| iounmap(data->pmi_reg); |
| |
| spin_lock(&data->handler_spinlock); |
| |
| list_for_each_entry_safe(handler, tmp, &data->handler, node) |
| list_del(&handler->node); |
| |
| spin_unlock(&data->handler_spinlock); |
| |
| kfree(data); |
| data = NULL; |
| |
| return 0; |
| } |
| |
| static struct platform_driver pmi_of_platform_driver = { |
| .probe = pmi_of_probe, |
| .remove = pmi_of_remove, |
| .driver = { |
| .name = "pmi", |
| .of_match_table = pmi_match, |
| }, |
| }; |
| module_platform_driver(pmi_of_platform_driver); |
| |
| int pmi_send_message(pmi_message_t msg) |
| { |
| unsigned long flags; |
| DECLARE_COMPLETION_ONSTACK(completion); |
| |
| if (!data) |
| return -ENODEV; |
| |
| mutex_lock(&data->msg_mutex); |
| |
| data->msg = msg; |
| pr_debug("pmi_send_message: msg is %08x\n", *(u32*)&msg); |
| |
| data->completion = &completion; |
| |
| spin_lock_irqsave(&data->pmi_spinlock, flags); |
| iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0); |
| iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1); |
| iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2); |
| iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE); |
| spin_unlock_irqrestore(&data->pmi_spinlock, flags); |
| |
| pr_debug("pmi_send_message: wait for completion\n"); |
| |
| wait_for_completion_interruptible_timeout(data->completion, |
| PMI_TIMEOUT); |
| |
| data->completion = NULL; |
| |
| mutex_unlock(&data->msg_mutex); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(pmi_send_message); |
| |
| int pmi_register_handler(struct pmi_handler *handler) |
| { |
| if (!data) |
| return -ENODEV; |
| |
| spin_lock(&data->handler_spinlock); |
| list_add_tail(&handler->node, &data->handler); |
| spin_unlock(&data->handler_spinlock); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(pmi_register_handler); |
| |
| void pmi_unregister_handler(struct pmi_handler *handler) |
| { |
| if (!data) |
| return; |
| |
| pr_debug("pmi: unregistering handler %p\n", handler); |
| |
| spin_lock(&data->handler_spinlock); |
| list_del(&handler->node); |
| spin_unlock(&data->handler_spinlock); |
| } |
| EXPORT_SYMBOL_GPL(pmi_unregister_handler); |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>"); |
| MODULE_DESCRIPTION("IBM Platform Management Interrupt driver"); |