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uwb: don't unbind the radio controller driver when resetting

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Use pre_reset and post_reset methods to avoid unbinding the radio
controller driver after a uwb_rc_reset_all() call.  This avoids a
deadlock in uwb_rc_rm() when waiting for the uwb event thread to stop.

Signed-off-by: David Vrabel <david.vrabel@csr.com>
This commit is contained in:
David Vrabel
2008-11-07 17:37:33 +00:00
parent fec1a5932f
commit 307ba6dd73
8 changed files with 155 additions and 42 deletions
Download Patch File Download Diff File Expand all files Collapse all files

62
drivers/uwb/umc-bus.c
View File

@ -11,23 +11,48 @@
#include <linux/uwb/umc.h>
#include <linux/pci.h>
static int umc_bus_unbind_helper(struct device *dev, void *data)
static int umc_bus_pre_reset_helper(struct device *dev, void *data)
{
struct device *parent = data;
int ret = 0;
if (dev->parent == parent && dev->driver)
device_release_driver(dev);
return 0;
if (dev->driver) {
struct umc_dev *umc = to_umc_dev(dev);
struct umc_driver *umc_drv = to_umc_driver(dev->driver);
if (umc_drv->pre_reset)
ret = umc_drv->pre_reset(umc);
else
device_release_driver(dev);
}
return ret;
}
static int umc_bus_post_reset_helper(struct device *dev, void *data)
{
int ret = 0;
if (dev->driver) {
struct umc_dev *umc = to_umc_dev(dev);
struct umc_driver *umc_drv = to_umc_driver(dev->driver);
if (umc_drv->post_reset)
ret = umc_drv->post_reset(umc);
} else
ret = device_attach(dev);
return ret;
}
/**
* umc_controller_reset - reset the whole UMC controller
* @umc: the UMC device for the radio controller.
*
* Drivers will be unbound from all UMC devices belonging to the
* controller and then the radio controller will be rebound. The
* radio controller is expected to do a full hardware reset when it is
* probed.
* Drivers or all capabilities of the controller will have their
* pre_reset methods called or be unbound from their device. Then all
* post_reset methods will be called or the drivers will be rebound.
*
* Radio controllers must provide pre_reset and post_reset methods and
* reset the hardware in their start method.
*
* If this is called while a probe() or remove() is in progress it
* will return -EAGAIN and not perform the reset.
@ -35,14 +60,13 @@ static int umc_bus_unbind_helper(struct device *dev, void *data)
int umc_controller_reset(struct umc_dev *umc)
{
struct device *parent = umc->dev.parent;
int ret;
int ret = 0;
if (down_trylock(&parent->sem))
if(down_trylock(&parent->sem))
return -EAGAIN;
bus_for_each_dev(&umc_bus_type, NULL, parent, umc_bus_unbind_helper);
ret = device_attach(&umc->dev);
if (ret == 1)
ret = 0;
ret = device_for_each_child(parent, parent, umc_bus_pre_reset_helper);
if (ret >= 0)
device_for_each_child(parent, parent, umc_bus_post_reset_helper);
up(&parent->sem);
return ret;
@ -75,10 +99,10 @@ static int umc_bus_rescan_helper(struct device *dev, void *data)
if (!dev->driver)
ret = device_attach(dev);
return ret < 0 ? ret : 0;
return ret;
}
static void umc_bus_rescan(void)
static void umc_bus_rescan(struct device *parent)
{
int err;
@ -86,7 +110,7 @@ static void umc_bus_rescan(void)
* We can't use bus_rescan_devices() here as it deadlocks when
* it tries to retake the dev->parent semaphore.
*/
err = bus_for_each_dev(&umc_bus_type, NULL, NULL, umc_bus_rescan_helper);
err = device_for_each_child(parent, NULL, umc_bus_rescan_helper);
if (err < 0)
printk(KERN_WARNING "%s: rescan of bus failed: %d\n",
KBUILD_MODNAME, err);
@ -120,7 +144,7 @@ static int umc_device_probe(struct device *dev)
if (err)
put_device(dev);
else
umc_bus_rescan();
umc_bus_rescan(dev->parent);
return err;
}