diff options
Diffstat (limited to 'arch/powerpc/sysdev/pmi.c')
| -rw-r--r-- | arch/powerpc/sysdev/pmi.c | 269 |
1 files changed, 269 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/pmi.c b/arch/powerpc/sysdev/pmi.c new file mode 100644 index 000000000..9dabb50c3 --- /dev/null +++ b/arch/powerpc/sysdev/pmi.c @@ -0,0 +1,269 @@ +// 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"); |