linux/drivers/base/platform.c
Jean Delvare dc4c15d44b platform: reorder platform_device_del
In platform_device_del(), we currently delete the device resources
first, then we delete the device itself. This causes a (minor) bug to
occur when one unregisters a platform device before unregistering its
platform driver, and the driver is requesting (in .probe()) and
releasing (in .remove()) a resource of the device. The device
resources are already gone by the time the driver gets the chance to
release the resources it had been requesting, causing an error like:
Trying to free nonexistent resource <0000000000000295-0000000000000296>

If the platform driver is unregistered first, the problem doesn't
occur, as the driver will have the opportunity to release the
resources it had requested before the device resources themselves are
released. It's a bit odd that unregistering the driver first or the
device first doesn't lead to the same result.

So I believe that we should delete the device first in
platform_device_del(). I've searched the git history and found that it
used to be the case before 2.6.8, but was changed here:

http://www.kernel.org/git/?p=linux/kernel/git/torvalds/old-2.6-bkcvs.git;a=commitdiff;h=96ef7b3689936ee1e64b711511342026a8ce459c

> 2004/07/14 16:09:44-07:00 dtor_core
> [PATCH] Driver core: Fix OOPS in device_platform_unregister
> 
> Driver core: platform_device_unregister should release resources first
>              and only then call device_unregister, otherwise if there
>              are no more references to the device it will be freed and
>              the fucntion will try to access freed memory.  

However we now have an explicit call to put_device() at the end of
platform_device_unregister() so I guess the original problem no longer
exists and it is safe to revert that change.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-05-02 18:57:59 -07:00

648 lines
17 KiB
C

/*
* platform.c - platform 'pseudo' bus for legacy devices
*
* Copyright (c) 2002-3 Patrick Mochel
* Copyright (c) 2002-3 Open Source Development Labs
*
* This file is released under the GPLv2
*
* Please see Documentation/driver-model/platform.txt for more
* information.
*/
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/dma-mapping.h>
#include <linux/bootmem.h>
#include <linux/err.h>
#include <linux/slab.h>
#include "base.h"
#define to_platform_driver(drv) (container_of((drv), struct platform_driver, driver))
struct device platform_bus = {
.bus_id = "platform",
};
EXPORT_SYMBOL_GPL(platform_bus);
/**
* platform_get_resource - get a resource for a device
* @dev: platform device
* @type: resource type
* @num: resource index
*/
struct resource *
platform_get_resource(struct platform_device *dev, unsigned int type,
unsigned int num)
{
int i;
for (i = 0; i < dev->num_resources; i++) {
struct resource *r = &dev->resource[i];
if ((r->flags & (IORESOURCE_IO|IORESOURCE_MEM|
IORESOURCE_IRQ|IORESOURCE_DMA))
== type)
if (num-- == 0)
return r;
}
return NULL;
}
EXPORT_SYMBOL_GPL(platform_get_resource);
/**
* platform_get_irq - get an IRQ for a device
* @dev: platform device
* @num: IRQ number index
*/
int platform_get_irq(struct platform_device *dev, unsigned int num)
{
struct resource *r = platform_get_resource(dev, IORESOURCE_IRQ, num);
return r ? r->start : -ENXIO;
}
EXPORT_SYMBOL_GPL(platform_get_irq);
/**
* platform_get_resource_byname - get a resource for a device by name
* @dev: platform device
* @type: resource type
* @name: resource name
*/
struct resource *
platform_get_resource_byname(struct platform_device *dev, unsigned int type,
char *name)
{
int i;
for (i = 0; i < dev->num_resources; i++) {
struct resource *r = &dev->resource[i];
if ((r->flags & (IORESOURCE_IO|IORESOURCE_MEM|
IORESOURCE_IRQ|IORESOURCE_DMA)) == type)
if (!strcmp(r->name, name))
return r;
}
return NULL;
}
EXPORT_SYMBOL_GPL(platform_get_resource_byname);
/**
* platform_get_irq - get an IRQ for a device
* @dev: platform device
* @name: IRQ name
*/
int platform_get_irq_byname(struct platform_device *dev, char *name)
{
struct resource *r = platform_get_resource_byname(dev, IORESOURCE_IRQ, name);
return r ? r->start : -ENXIO;
}
EXPORT_SYMBOL_GPL(platform_get_irq_byname);
/**
* platform_add_devices - add a numbers of platform devices
* @devs: array of platform devices to add
* @num: number of platform devices in array
*/
int platform_add_devices(struct platform_device **devs, int num)
{
int i, ret = 0;
for (i = 0; i < num; i++) {
ret = platform_device_register(devs[i]);
if (ret) {
while (--i >= 0)
platform_device_unregister(devs[i]);
break;
}
}
return ret;
}
EXPORT_SYMBOL_GPL(platform_add_devices);
struct platform_object {
struct platform_device pdev;
char name[1];
};
/**
* platform_device_put
* @pdev: platform device to free
*
* Free all memory associated with a platform device. This function
* must _only_ be externally called in error cases. All other usage
* is a bug.
*/
void platform_device_put(struct platform_device *pdev)
{
if (pdev)
put_device(&pdev->dev);
}
EXPORT_SYMBOL_GPL(platform_device_put);
static void platform_device_release(struct device *dev)
{
struct platform_object *pa = container_of(dev, struct platform_object, pdev.dev);
kfree(pa->pdev.dev.platform_data);
kfree(pa->pdev.resource);
kfree(pa);
}
/**
* platform_device_alloc
* @name: base name of the device we're adding
* @id: instance id
*
* Create a platform device object which can have other objects attached
* to it, and which will have attached objects freed when it is released.
*/
struct platform_device *platform_device_alloc(const char *name, unsigned int id)
{
struct platform_object *pa;
pa = kzalloc(sizeof(struct platform_object) + strlen(name), GFP_KERNEL);
if (pa) {
strcpy(pa->name, name);
pa->pdev.name = pa->name;
pa->pdev.id = id;
device_initialize(&pa->pdev.dev);
pa->pdev.dev.release = platform_device_release;
}
return pa ? &pa->pdev : NULL;
}
EXPORT_SYMBOL_GPL(platform_device_alloc);
/**
* platform_device_add_resources
* @pdev: platform device allocated by platform_device_alloc to add resources to
* @res: set of resources that needs to be allocated for the device
* @num: number of resources
*
* Add a copy of the resources to the platform device. The memory
* associated with the resources will be freed when the platform
* device is released.
*/
int platform_device_add_resources(struct platform_device *pdev, struct resource *res, unsigned int num)
{
struct resource *r;
r = kmalloc(sizeof(struct resource) * num, GFP_KERNEL);
if (r) {
memcpy(r, res, sizeof(struct resource) * num);
pdev->resource = r;
pdev->num_resources = num;
}
return r ? 0 : -ENOMEM;
}
EXPORT_SYMBOL_GPL(platform_device_add_resources);
/**
* platform_device_add_data
* @pdev: platform device allocated by platform_device_alloc to add resources to
* @data: platform specific data for this platform device
* @size: size of platform specific data
*
* Add a copy of platform specific data to the platform device's platform_data
* pointer. The memory associated with the platform data will be freed
* when the platform device is released.
*/
int platform_device_add_data(struct platform_device *pdev, const void *data, size_t size)
{
void *d;
d = kmalloc(size, GFP_KERNEL);
if (d) {
memcpy(d, data, size);
pdev->dev.platform_data = d;
}
return d ? 0 : -ENOMEM;
}
EXPORT_SYMBOL_GPL(platform_device_add_data);
/**
* platform_device_add - add a platform device to device hierarchy
* @pdev: platform device we're adding
*
* This is part 2 of platform_device_register(), though may be called
* separately _iff_ pdev was allocated by platform_device_alloc().
*/
int platform_device_add(struct platform_device *pdev)
{
int i, ret = 0;
if (!pdev)
return -EINVAL;
if (!pdev->dev.parent)
pdev->dev.parent = &platform_bus;
pdev->dev.bus = &platform_bus_type;
if (pdev->id != -1)
snprintf(pdev->dev.bus_id, BUS_ID_SIZE, "%s.%u", pdev->name, pdev->id);
else
strlcpy(pdev->dev.bus_id, pdev->name, BUS_ID_SIZE);
for (i = 0; i < pdev->num_resources; i++) {
struct resource *p, *r = &pdev->resource[i];
if (r->name == NULL)
r->name = pdev->dev.bus_id;
p = r->parent;
if (!p) {
if (r->flags & IORESOURCE_MEM)
p = &iomem_resource;
else if (r->flags & IORESOURCE_IO)
p = &ioport_resource;
}
if (p && insert_resource(p, r)) {
printk(KERN_ERR
"%s: failed to claim resource %d\n",
pdev->dev.bus_id, i);
ret = -EBUSY;
goto failed;
}
}
pr_debug("Registering platform device '%s'. Parent at %s\n",
pdev->dev.bus_id, pdev->dev.parent->bus_id);
ret = device_add(&pdev->dev);
if (ret == 0)
return ret;
failed:
while (--i >= 0)
if (pdev->resource[i].flags & (IORESOURCE_MEM|IORESOURCE_IO))
release_resource(&pdev->resource[i]);
return ret;
}
EXPORT_SYMBOL_GPL(platform_device_add);
/**
* platform_device_del - remove a platform-level device
* @pdev: platform device we're removing
*
* Note that this function will also release all memory- and port-based
* resources owned by the device (@dev->resource). This function
* must _only_ be externally called in error cases. All other usage
* is a bug.
*/
void platform_device_del(struct platform_device *pdev)
{
int i;
if (pdev) {
device_del(&pdev->dev);
for (i = 0; i < pdev->num_resources; i++) {
struct resource *r = &pdev->resource[i];
if (r->flags & (IORESOURCE_MEM|IORESOURCE_IO))
release_resource(r);
}
}
}
EXPORT_SYMBOL_GPL(platform_device_del);
/**
* platform_device_register - add a platform-level device
* @pdev: platform device we're adding
*
*/
int platform_device_register(struct platform_device * pdev)
{
device_initialize(&pdev->dev);
return platform_device_add(pdev);
}
EXPORT_SYMBOL_GPL(platform_device_register);
/**
* platform_device_unregister - unregister a platform-level device
* @pdev: platform device we're unregistering
*
* Unregistration is done in 2 steps. First we release all resources
* and remove it from the subsystem, then we drop reference count by
* calling platform_device_put().
*/
void platform_device_unregister(struct platform_device * pdev)
{
platform_device_del(pdev);
platform_device_put(pdev);
}
EXPORT_SYMBOL_GPL(platform_device_unregister);
/**
* platform_device_register_simple
* @name: base name of the device we're adding
* @id: instance id
* @res: set of resources that needs to be allocated for the device
* @num: number of resources
*
* This function creates a simple platform device that requires minimal
* resource and memory management. Canned release function freeing
* memory allocated for the device allows drivers using such devices
* to be unloaded iwithout waiting for the last reference to the device
* to be dropped.
*/
struct platform_device *platform_device_register_simple(char *name, unsigned int id,
struct resource *res, unsigned int num)
{
struct platform_device *pdev;
int retval;
pdev = platform_device_alloc(name, id);
if (!pdev) {
retval = -ENOMEM;
goto error;
}
if (num) {
retval = platform_device_add_resources(pdev, res, num);
if (retval)
goto error;
}
retval = platform_device_add(pdev);
if (retval)
goto error;
return pdev;
error:
platform_device_put(pdev);
return ERR_PTR(retval);
}
EXPORT_SYMBOL_GPL(platform_device_register_simple);
static int platform_drv_probe(struct device *_dev)
{
struct platform_driver *drv = to_platform_driver(_dev->driver);
struct platform_device *dev = to_platform_device(_dev);
return drv->probe(dev);
}
static int platform_drv_probe_fail(struct device *_dev)
{
return -ENXIO;
}
static int platform_drv_remove(struct device *_dev)
{
struct platform_driver *drv = to_platform_driver(_dev->driver);
struct platform_device *dev = to_platform_device(_dev);
return drv->remove(dev);
}
static void platform_drv_shutdown(struct device *_dev)
{
struct platform_driver *drv = to_platform_driver(_dev->driver);
struct platform_device *dev = to_platform_device(_dev);
drv->shutdown(dev);
}
static int platform_drv_suspend(struct device *_dev, pm_message_t state)
{
struct platform_driver *drv = to_platform_driver(_dev->driver);
struct platform_device *dev = to_platform_device(_dev);
return drv->suspend(dev, state);
}
static int platform_drv_resume(struct device *_dev)
{
struct platform_driver *drv = to_platform_driver(_dev->driver);
struct platform_device *dev = to_platform_device(_dev);
return drv->resume(dev);
}
/**
* platform_driver_register
* @drv: platform driver structure
*/
int platform_driver_register(struct platform_driver *drv)
{
drv->driver.bus = &platform_bus_type;
if (drv->probe)
drv->driver.probe = platform_drv_probe;
if (drv->remove)
drv->driver.remove = platform_drv_remove;
if (drv->shutdown)
drv->driver.shutdown = platform_drv_shutdown;
if (drv->suspend)
drv->driver.suspend = platform_drv_suspend;
if (drv->resume)
drv->driver.resume = platform_drv_resume;
return driver_register(&drv->driver);
}
EXPORT_SYMBOL_GPL(platform_driver_register);
/**
* platform_driver_unregister
* @drv: platform driver structure
*/
void platform_driver_unregister(struct platform_driver *drv)
{
driver_unregister(&drv->driver);
}
EXPORT_SYMBOL_GPL(platform_driver_unregister);
/**
* platform_driver_probe - register driver for non-hotpluggable device
* @drv: platform driver structure
* @probe: the driver probe routine, probably from an __init section
*
* Use this instead of platform_driver_register() when you know the device
* is not hotpluggable and has already been registered, and you want to
* remove its run-once probe() infrastructure from memory after the driver
* has bound to the device.
*
* One typical use for this would be with drivers for controllers integrated
* into system-on-chip processors, where the controller devices have been
* configured as part of board setup.
*
* Returns zero if the driver registered and bound to a device, else returns
* a negative error code and with the driver not registered.
*/
int __init_or_module platform_driver_probe(struct platform_driver *drv,
int (*probe)(struct platform_device *))
{
int retval, code;
/* temporary section violation during probe() */
drv->probe = probe;
retval = code = platform_driver_register(drv);
/* Fixup that section violation, being paranoid about code scanning
* the list of drivers in order to probe new devices. Check to see
* if the probe was successful, and make sure any forced probes of
* new devices fail.
*/
spin_lock(&platform_bus_type.klist_drivers.k_lock);
drv->probe = NULL;
if (code == 0 && list_empty(&drv->driver.klist_devices.k_list))
retval = -ENODEV;
drv->driver.probe = platform_drv_probe_fail;
spin_unlock(&platform_bus_type.klist_drivers.k_lock);
if (code != retval)
platform_driver_unregister(drv);
return retval;
}
EXPORT_SYMBOL_GPL(platform_driver_probe);
/* modalias support enables more hands-off userspace setup:
* (a) environment variable lets new-style hotplug events work once system is
* fully running: "modprobe $MODALIAS"
* (b) sysfs attribute lets new-style coldplug recover from hotplug events
* mishandled before system is fully running: "modprobe $(cat modalias)"
*/
static ssize_t
modalias_show(struct device *dev, struct device_attribute *a, char *buf)
{
struct platform_device *pdev = to_platform_device(dev);
int len = snprintf(buf, PAGE_SIZE, "%s\n", pdev->name);
return (len >= PAGE_SIZE) ? (PAGE_SIZE - 1) : len;
}
static struct device_attribute platform_dev_attrs[] = {
__ATTR_RO(modalias),
__ATTR_NULL,
};
static int platform_uevent(struct device *dev, char **envp, int num_envp,
char *buffer, int buffer_size)
{
struct platform_device *pdev = to_platform_device(dev);
envp[0] = buffer;
snprintf(buffer, buffer_size, "MODALIAS=%s", pdev->name);
return 0;
}
/**
* platform_match - bind platform device to platform driver.
* @dev: device.
* @drv: driver.
*
* Platform device IDs are assumed to be encoded like this:
* "<name><instance>", where <name> is a short description of the
* type of device, like "pci" or "floppy", and <instance> is the
* enumerated instance of the device, like '0' or '42'.
* Driver IDs are simply "<name>".
* So, extract the <name> from the platform_device structure,
* and compare it against the name of the driver. Return whether
* they match or not.
*/
static int platform_match(struct device * dev, struct device_driver * drv)
{
struct platform_device *pdev = container_of(dev, struct platform_device, dev);
return (strncmp(pdev->name, drv->name, BUS_ID_SIZE) == 0);
}
static int platform_suspend(struct device *dev, pm_message_t mesg)
{
int ret = 0;
if (dev->driver && dev->driver->suspend)
ret = dev->driver->suspend(dev, mesg);
return ret;
}
static int platform_suspend_late(struct device *dev, pm_message_t mesg)
{
struct platform_driver *drv = to_platform_driver(dev->driver);
struct platform_device *pdev = container_of(dev, struct platform_device, dev);
int ret = 0;
if (dev->driver && drv->suspend_late)
ret = drv->suspend_late(pdev, mesg);
return ret;
}
static int platform_resume_early(struct device *dev)
{
struct platform_driver *drv = to_platform_driver(dev->driver);
struct platform_device *pdev = container_of(dev, struct platform_device, dev);
int ret = 0;
if (dev->driver && drv->resume_early)
ret = drv->resume_early(pdev);
return ret;
}
static int platform_resume(struct device * dev)
{
int ret = 0;
if (dev->driver && dev->driver->resume)
ret = dev->driver->resume(dev);
return ret;
}
struct bus_type platform_bus_type = {
.name = "platform",
.dev_attrs = platform_dev_attrs,
.match = platform_match,
.uevent = platform_uevent,
.suspend = platform_suspend,
.suspend_late = platform_suspend_late,
.resume_early = platform_resume_early,
.resume = platform_resume,
};
EXPORT_SYMBOL_GPL(platform_bus_type);
int __init platform_bus_init(void)
{
int error;
error = device_register(&platform_bus);
if (error)
return error;
error = bus_register(&platform_bus_type);
if (error)
device_unregister(&platform_bus);
return error;
}
#ifndef ARCH_HAS_DMA_GET_REQUIRED_MASK
u64 dma_get_required_mask(struct device *dev)
{
u32 low_totalram = ((max_pfn - 1) << PAGE_SHIFT);
u32 high_totalram = ((max_pfn - 1) >> (32 - PAGE_SHIFT));
u64 mask;
if (!high_totalram) {
/* convert to mask just covering totalram */
low_totalram = (1 << (fls(low_totalram) - 1));
low_totalram += low_totalram - 1;
mask = low_totalram;
} else {
high_totalram = (1 << (fls(high_totalram) - 1));
high_totalram += high_totalram - 1;
mask = (((u64)high_totalram) << 32) + 0xffffffff;
}
return mask & *dev->dma_mask;
}
EXPORT_SYMBOL_GPL(dma_get_required_mask);
#endif