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