blob: 9dabb50c36eb268660165993a29144c5d15ed8da [file] [log] [blame]
// 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");