linux-stable/arch/powerpc/sysdev/pmi.c
Uwe Kleine-König a3e1820186 powerpc: pmi: Convert to platform remove callback returning void
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/3201daed6d19c01ee0ee72e0f9302a38ecef3577.1708529736.git.u.kleine-koenig@pengutronix.de
2024-02-22 21:55:33 +11:00

267 lines
5.8 KiB
C

// 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/mod_devicetable.h>
#include <linux/workqueue.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/platform_device.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 void 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;
}
static struct platform_driver pmi_of_platform_driver = {
.probe = pmi_of_probe,
.remove_new = 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");