linux/drivers/mcb/mcb-core.c
Johannes Thumshirn 4d2ec85753 mcb: Acquire reference to carrier module in core
Acquire a reference to the carrier's kernel module in bus code, so
it can't be removed from the kernel while it still has a bus and thus
possibly devices attached to it.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reported-by: Andreas Werner <andreas.werner@men.de>
Tested-by: Andreas Werner <andreas.werner@men.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-13 18:49:30 -07:00

522 lines
11 KiB
C

/*
* MEN Chameleon Bus.
*
* Copyright (C) 2013 MEN Mikroelektronik GmbH (www.men.de)
* Author: Johannes Thumshirn <johannes.thumshirn@men.de>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; version 2 of the License.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/idr.h>
#include <linux/mcb.h>
static DEFINE_IDA(mcb_ida);
static const struct mcb_device_id *mcb_match_id(const struct mcb_device_id *ids,
struct mcb_device *dev)
{
if (ids) {
while (ids->device) {
if (ids->device == dev->id)
return ids;
ids++;
}
}
return NULL;
}
static int mcb_match(struct device *dev, struct device_driver *drv)
{
struct mcb_driver *mdrv = to_mcb_driver(drv);
struct mcb_device *mdev = to_mcb_device(dev);
const struct mcb_device_id *found_id;
found_id = mcb_match_id(mdrv->id_table, mdev);
if (found_id)
return 1;
return 0;
}
static int mcb_uevent(struct device *dev, struct kobj_uevent_env *env)
{
struct mcb_device *mdev = to_mcb_device(dev);
int ret;
ret = add_uevent_var(env, "MODALIAS=mcb:16z%03d", mdev->id);
if (ret)
return -ENOMEM;
return 0;
}
static int mcb_probe(struct device *dev)
{
struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
struct mcb_device *mdev = to_mcb_device(dev);
const struct mcb_device_id *found_id;
struct module *carrier_mod;
int ret;
found_id = mcb_match_id(mdrv->id_table, mdev);
if (!found_id)
return -ENODEV;
carrier_mod = mdev->dev.parent->driver->owner;
if (!try_module_get(carrier_mod))
return -EINVAL;
get_device(dev);
ret = mdrv->probe(mdev, found_id);
if (ret)
module_put(carrier_mod);
return ret;
}
static int mcb_remove(struct device *dev)
{
struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
struct mcb_device *mdev = to_mcb_device(dev);
struct module *carrier_mod;
mdrv->remove(mdev);
carrier_mod = mdev->dev.parent->driver->owner;
module_put(carrier_mod);
put_device(&mdev->dev);
return 0;
}
static void mcb_shutdown(struct device *dev)
{
struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
struct mcb_device *mdev = to_mcb_device(dev);
if (mdrv && mdrv->shutdown)
mdrv->shutdown(mdev);
}
static ssize_t revision_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct mcb_bus *bus = to_mcb_bus(dev);
return scnprintf(buf, PAGE_SIZE, "%d\n", bus->revision);
}
static DEVICE_ATTR_RO(revision);
static ssize_t model_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct mcb_bus *bus = to_mcb_bus(dev);
return scnprintf(buf, PAGE_SIZE, "%c\n", bus->model);
}
static DEVICE_ATTR_RO(model);
static ssize_t minor_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct mcb_bus *bus = to_mcb_bus(dev);
return scnprintf(buf, PAGE_SIZE, "%d\n", bus->minor);
}
static DEVICE_ATTR_RO(minor);
static ssize_t name_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct mcb_bus *bus = to_mcb_bus(dev);
return scnprintf(buf, PAGE_SIZE, "%s\n", bus->name);
}
static DEVICE_ATTR_RO(name);
static struct attribute *mcb_bus_attrs[] = {
&dev_attr_revision.attr,
&dev_attr_model.attr,
&dev_attr_minor.attr,
&dev_attr_name.attr,
NULL,
};
static const struct attribute_group mcb_carrier_group = {
.attrs = mcb_bus_attrs,
};
static const struct attribute_group *mcb_carrier_groups[] = {
&mcb_carrier_group,
NULL,
};
static struct bus_type mcb_bus_type = {
.name = "mcb",
.match = mcb_match,
.uevent = mcb_uevent,
.probe = mcb_probe,
.remove = mcb_remove,
.shutdown = mcb_shutdown,
};
static struct device_type mcb_carrier_device_type = {
.name = "mcb-carrier",
.groups = mcb_carrier_groups,
};
/**
* __mcb_register_driver() - Register a @mcb_driver at the system
* @drv: The @mcb_driver
* @owner: The @mcb_driver's module
* @mod_name: The name of the @mcb_driver's module
*
* Register a @mcb_driver at the system. Perform some sanity checks, if
* the .probe and .remove methods are provided by the driver.
*/
int __mcb_register_driver(struct mcb_driver *drv, struct module *owner,
const char *mod_name)
{
if (!drv->probe || !drv->remove)
return -EINVAL;
drv->driver.owner = owner;
drv->driver.bus = &mcb_bus_type;
drv->driver.mod_name = mod_name;
return driver_register(&drv->driver);
}
EXPORT_SYMBOL_GPL(__mcb_register_driver);
/**
* mcb_unregister_driver() - Unregister a @mcb_driver from the system
* @drv: The @mcb_driver
*
* Unregister a @mcb_driver from the system.
*/
void mcb_unregister_driver(struct mcb_driver *drv)
{
driver_unregister(&drv->driver);
}
EXPORT_SYMBOL_GPL(mcb_unregister_driver);
static void mcb_release_dev(struct device *dev)
{
struct mcb_device *mdev = to_mcb_device(dev);
mcb_bus_put(mdev->bus);
kfree(mdev);
}
/**
* mcb_device_register() - Register a mcb_device
* @bus: The @mcb_bus of the device
* @dev: The @mcb_device
*
* Register a specific @mcb_device at a @mcb_bus and the system itself.
*/
int mcb_device_register(struct mcb_bus *bus, struct mcb_device *dev)
{
int ret;
int device_id;
device_initialize(&dev->dev);
mcb_bus_get(bus);
dev->dev.bus = &mcb_bus_type;
dev->dev.parent = bus->dev.parent;
dev->dev.release = mcb_release_dev;
device_id = dev->id;
dev_set_name(&dev->dev, "mcb%d-16z%03d-%d:%d:%d",
bus->bus_nr, device_id, dev->inst, dev->group, dev->var);
ret = device_add(&dev->dev);
if (ret < 0) {
pr_err("Failed registering device 16z%03d on bus mcb%d (%d)\n",
device_id, bus->bus_nr, ret);
goto out;
}
return 0;
out:
return ret;
}
EXPORT_SYMBOL_GPL(mcb_device_register);
static void mcb_free_bus(struct device *dev)
{
struct mcb_bus *bus = to_mcb_bus(dev);
put_device(bus->carrier);
ida_simple_remove(&mcb_ida, bus->bus_nr);
kfree(bus);
}
/**
* mcb_alloc_bus() - Allocate a new @mcb_bus
*
* Allocate a new @mcb_bus.
*/
struct mcb_bus *mcb_alloc_bus(struct device *carrier)
{
struct mcb_bus *bus;
int bus_nr;
int rc;
bus = kzalloc(sizeof(struct mcb_bus), GFP_KERNEL);
if (!bus)
return ERR_PTR(-ENOMEM);
bus_nr = ida_simple_get(&mcb_ida, 0, 0, GFP_KERNEL);
if (bus_nr < 0) {
rc = bus_nr;
goto err_free;
}
bus->bus_nr = bus_nr;
bus->carrier = get_device(carrier);
device_initialize(&bus->dev);
bus->dev.parent = carrier;
bus->dev.bus = &mcb_bus_type;
bus->dev.type = &mcb_carrier_device_type;
bus->dev.release = &mcb_free_bus;
dev_set_name(&bus->dev, "mcb:%d", bus_nr);
rc = device_add(&bus->dev);
if (rc)
goto err_free;
return bus;
err_free:
put_device(carrier);
kfree(bus);
return ERR_PTR(rc);
}
EXPORT_SYMBOL_GPL(mcb_alloc_bus);
static int __mcb_devices_unregister(struct device *dev, void *data)
{
device_unregister(dev);
return 0;
}
static void mcb_devices_unregister(struct mcb_bus *bus)
{
bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_devices_unregister);
}
/**
* mcb_release_bus() - Free a @mcb_bus
* @bus: The @mcb_bus to release
*
* Release an allocated @mcb_bus from the system.
*/
void mcb_release_bus(struct mcb_bus *bus)
{
mcb_devices_unregister(bus);
}
EXPORT_SYMBOL_GPL(mcb_release_bus);
/**
* mcb_bus_put() - Increment refcnt
* @bus: The @mcb_bus
*
* Get a @mcb_bus' ref
*/
struct mcb_bus *mcb_bus_get(struct mcb_bus *bus)
{
if (bus)
get_device(&bus->dev);
return bus;
}
EXPORT_SYMBOL_GPL(mcb_bus_get);
/**
* mcb_bus_put() - Decrement refcnt
* @bus: The @mcb_bus
*
* Release a @mcb_bus' ref
*/
void mcb_bus_put(struct mcb_bus *bus)
{
if (bus)
put_device(&bus->dev);
}
EXPORT_SYMBOL_GPL(mcb_bus_put);
/**
* mcb_alloc_dev() - Allocate a device
* @bus: The @mcb_bus the device is part of
*
* Allocate a @mcb_device and add bus.
*/
struct mcb_device *mcb_alloc_dev(struct mcb_bus *bus)
{
struct mcb_device *dev;
dev = kzalloc(sizeof(struct mcb_device), GFP_KERNEL);
if (!dev)
return NULL;
INIT_LIST_HEAD(&dev->bus_list);
dev->bus = bus;
return dev;
}
EXPORT_SYMBOL_GPL(mcb_alloc_dev);
/**
* mcb_free_dev() - Free @mcb_device
* @dev: The device to free
*
* Free a @mcb_device
*/
void mcb_free_dev(struct mcb_device *dev)
{
kfree(dev);
}
EXPORT_SYMBOL_GPL(mcb_free_dev);
static int __mcb_bus_add_devices(struct device *dev, void *data)
{
struct mcb_device *mdev = to_mcb_device(dev);
int retval;
if (mdev->is_added)
return 0;
retval = device_attach(dev);
if (retval < 0)
dev_err(dev, "Error adding device (%d)\n", retval);
mdev->is_added = true;
return 0;
}
static int __mcb_bus_add_child(struct device *dev, void *data)
{
struct mcb_device *mdev = to_mcb_device(dev);
struct mcb_bus *child;
BUG_ON(!mdev->is_added);
child = mdev->subordinate;
if (child)
mcb_bus_add_devices(child);
return 0;
}
/**
* mcb_bus_add_devices() - Add devices in the bus' internal device list
* @bus: The @mcb_bus we add the devices
*
* Add devices in the bus' internal device list to the system.
*/
void mcb_bus_add_devices(const struct mcb_bus *bus)
{
bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_bus_add_devices);
bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_bus_add_child);
}
EXPORT_SYMBOL_GPL(mcb_bus_add_devices);
/**
* mcb_request_mem() - Request memory
* @dev: The @mcb_device the memory is for
* @name: The name for the memory reference.
*
* Request memory for a @mcb_device. If @name is NULL the driver name will
* be used.
*/
struct resource *mcb_request_mem(struct mcb_device *dev, const char *name)
{
struct resource *mem;
u32 size;
if (!name)
name = dev->dev.driver->name;
size = resource_size(&dev->mem);
mem = request_mem_region(dev->mem.start, size, name);
if (!mem)
return ERR_PTR(-EBUSY);
return mem;
}
EXPORT_SYMBOL_GPL(mcb_request_mem);
/**
* mcb_release_mem() - Release memory requested by device
* @dev: The @mcb_device that requested the memory
*
* Release memory that was prior requested via @mcb_request_mem().
*/
void mcb_release_mem(struct resource *mem)
{
u32 size;
size = resource_size(mem);
release_mem_region(mem->start, size);
}
EXPORT_SYMBOL_GPL(mcb_release_mem);
static int __mcb_get_irq(struct mcb_device *dev)
{
struct resource *irq = &dev->irq;
return irq->start;
}
/**
* mcb_get_irq() - Get device's IRQ number
* @dev: The @mcb_device the IRQ is for
*
* Get the IRQ number of a given @mcb_device.
*/
int mcb_get_irq(struct mcb_device *dev)
{
struct mcb_bus *bus = dev->bus;
if (bus->get_irq)
return bus->get_irq(dev);
return __mcb_get_irq(dev);
}
EXPORT_SYMBOL_GPL(mcb_get_irq);
static int mcb_init(void)
{
return bus_register(&mcb_bus_type);
}
static void mcb_exit(void)
{
ida_destroy(&mcb_ida);
bus_unregister(&mcb_bus_type);
}
/* mcb must be initialized after PCI but before the chameleon drivers.
* That means we must use some initcall between subsys_initcall and
* device_initcall.
*/
fs_initcall(mcb_init);
module_exit(mcb_exit);
MODULE_DESCRIPTION("MEN Chameleon Bus Driver");
MODULE_AUTHOR("Johannes Thumshirn <johannes.thumshirn@men.de>");
MODULE_LICENSE("GPL v2");