staging: vme: make match() driver specific to improve non-VME64x support

For jumper based boards (non VME64x), there is no mechanism
for detecting the card that is plugged into a specific slot. This
leads to issues in non-autodiscovery crates/cards when a card is
plugged into a slot that is "claimed" by a different driver. In
reality, there is no problem, but the driver rejects such a
configuration due to its dependence on the concept of slots.

This patch makes the concept of slots less critical and pushes the
driver match() to individual drivers (similar to what happens in the
ISA bus in driver/base/isa.c). This allows drivers to register the
number of devices that they expect without any restrictions. Devices
in this new model are now formatted as $driver_name-$bus_id.$device_id
(as compared to the earlier vme-$bus_id.$slot_number).

This model also makes the device model more logical as devices
are only registered when they actually exist whereas earlier,
a set of devices were being created automatically regardless of
them actually being there.

Another change introduced in this patch is that devices are now created
within the VME driver structure rather than in the VME bridge structure.
This way, things don't go haywire if the bridge driver is removed while
a driver is using it.

Signed-off-by: Manohar Vanga <manohar.vanga@cern.ch>
Cc: Martyn Welch <martyn.welch@ge.com>
Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 105 insertions, 97 deletions

diff --git a/drivers/staging/vme/vme.c b/drivers/staging/vme/vme.c
index 4bef7893dde0..2abb9ebd3d63 100644
--- a/drivers/staging/vme/vme.c
+++ b/drivers/staging/vme/vme.c
@@ -1317,6 +1317,7 @@ static int vme_add_bus(struct vme_bridge *bridge)
 		if ((vme_bus_numbers & (1 << i)) == 0) {
 			vme_bus_numbers |= (1 << i);
 			bridge->num = i;
+			INIT_LIST_HEAD(&bridge->devices);
 			list_add_tail(&bridge->bus_list, &vme_bus_list);
 			ret = 0;
 			break;
@@ -1329,8 +1330,16 @@ static int vme_add_bus(struct vme_bridge *bridge)
 
 static void vme_remove_bus(struct vme_bridge *bridge)
 {
+	struct vme_dev *vdev;
+	struct vme_dev *tmp;
+
 	mutex_lock(&vme_buses_lock);
 	vme_bus_numbers &= ~(1 << bridge->num);
+	list_for_each_entry_safe(vdev, tmp, &bridge->devices, bridge_list) {
+		list_del(&vdev->drv_list);
+		list_del(&vdev->bridge_list);
+		device_unregister(&vdev->dev);
+	}
 	list_del(&bridge->bus_list);
 	mutex_unlock(&vme_buses_lock);
 }
@@ -1342,153 +1351,153 @@ static void vme_dev_release(struct device *dev)
 
 int vme_register_bridge(struct vme_bridge *bridge)
 {
-	struct vme_dev *vdev;
-	int retval;
-	int i;
+	return vme_add_bus(bridge);
+}
+EXPORT_SYMBOL(vme_register_bridge);
 
-	retval = vme_add_bus(bridge);
-	if (retval)
-		return retval;
+void vme_unregister_bridge(struct vme_bridge *bridge)
+{
+	vme_remove_bus(bridge);
+}
+EXPORT_SYMBOL(vme_unregister_bridge);
 
-	/* This creates 32 vme "slot" devices. This equates to a slot for each
-	 * ID available in a system conforming to the ANSI/VITA 1-1994
-	 * specification.
-	 */
-	for (i = 0; i < VME_SLOTS_MAX; i++) {
-		bridge->dev[i] = kzalloc(sizeof(struct vme_dev), GFP_KERNEL);
-		if (!bridge->dev[i]) {
-			retval = -ENOMEM;
+/* - Driver Registration --------------------------------------------------- */
+
+static int __vme_register_driver_bus(struct vme_driver *drv,
+	struct vme_bridge *bridge, unsigned int ndevs)
+{
+	int err;
+	unsigned int i;
+	struct vme_dev *vdev;
+	struct vme_dev *tmp;
+
+	for (i = 0; i < ndevs; i++) {
+		vdev = kzalloc(sizeof(struct vme_dev), GFP_KERNEL);
+		if (!vdev) {
+			err = -ENOMEM;
 			goto err_devalloc;
 		}
-		vdev = bridge->dev[i];
-		memset(vdev, 0, sizeof(struct vme_dev));
-
+		vdev->id.num = i;
 		vdev->id.bus = bridge->num;
 		vdev->id.slot = i + 1;
 		vdev->bridge = bridge;
+		vdev->dev.platform_data = drv;
+		vdev->dev.release = vme_dev_release;
 		vdev->dev.parent = bridge->parent;
 		vdev->dev.bus = &vme_bus_type;
-		vdev->dev.release = vme_dev_release;
-		/*
-		 * We save a pointer to the bridge in platform_data so that we
-		 * can get to it later. We keep driver_data for use by the
-		 * driver that binds against the slot
-		 */
-		vdev->dev.platform_data = bridge;
-		dev_set_name(&vdev->dev, "vme-%x.%x", bridge->num, i + 1);
+		dev_set_name(&vdev->dev, "%s.%u-%u", drv->name, vdev->id.bus,
+			vdev->id.num);
 
-		retval = device_register(&vdev->dev);
-		if (retval)
+		err = device_register(&vdev->dev);
+		if (err)
 			goto err_reg;
-	}
 
-	return retval;
+		if (vdev->dev.platform_data) {
+			list_add_tail(&vdev->drv_list, &drv->devices);
+			list_add_tail(&vdev->bridge_list, &bridge->devices);
+		} else
+			device_unregister(&vdev->dev);
+	}
+	return 0;
 
 err_reg:
 	kfree(vdev);
 err_devalloc:
-	while (--i >= 0) {
-		vdev = bridge->dev[i];
+	list_for_each_entry_safe(vdev, tmp, &drv->devices, drv_list) {
+		list_del(&vdev->drv_list);
+		list_del(&vdev->bridge_list);
 		device_unregister(&vdev->dev);
 	}
-	vme_remove_bus(bridge);
-	return retval;
+	return err;
 }
-EXPORT_SYMBOL(vme_register_bridge);
 
-void vme_unregister_bridge(struct vme_bridge *bridge)
+static int __vme_register_driver(struct vme_driver *drv, unsigned int ndevs)
 {
-	int i;
-	struct vme_dev *vdev;
-
+	struct vme_bridge *bridge;
+	int err = 0;
 
-	for (i = 0; i < VME_SLOTS_MAX; i++) {
-		vdev = bridge->dev[i];
-		device_unregister(&vdev->dev);
+	mutex_lock(&vme_buses_lock);
+	list_for_each_entry(bridge, &vme_bus_list, bus_list) {
+		/*
+		 * This cannot cause trouble as we already have vme_buses_lock
+		 * and if the bridge is removed, it will have to go through
+		 * vme_unregister_bridge() to do it (which calls remove() on
+		 * the bridge which in turn tries to acquire vme_buses_lock and
+		 * will have to wait). The probe() called after device
+		 * registration in __vme_register_driver below will also fail
+		 * as the bridge is being removed (since the probe() calls
+		 * vme_bridge_get()).
+		 */
+		err = __vme_register_driver_bus(drv, bridge, ndevs);
+		if (err)
+			break;
 	}
-	vme_remove_bus(bridge);
+	mutex_unlock(&vme_buses_lock);
+	return err;
 }
-EXPORT_SYMBOL(vme_unregister_bridge);
-
-
-/* - Driver Registration --------------------------------------------------- */
 
-int vme_register_driver(struct vme_driver *drv)
+int vme_register_driver(struct vme_driver *drv, unsigned int ndevs)
 {
+	int err;
+
 	drv->driver.name = drv->name;
 	drv->driver.bus = &vme_bus_type;
+	INIT_LIST_HEAD(&drv->devices);
+
+	err = driver_register(&drv->driver);
+	if (err)
+		return err;
 
-	return driver_register(&drv->driver);
+	err = __vme_register_driver(drv, ndevs);
+	if (err)
+		driver_unregister(&drv->driver);
+
+	return err;
 }
 EXPORT_SYMBOL(vme_register_driver);
 
 void vme_unregister_driver(struct vme_driver *drv)
 {
+	struct vme_dev *dev, *dev_tmp;
+
+	mutex_lock(&vme_buses_lock);
+	list_for_each_entry_safe(dev, dev_tmp, &drv->devices, drv_list) {
+		list_del(&dev->drv_list);
+		list_del(&dev->bridge_list);
+		device_unregister(&dev->dev);
+	}
+	mutex_unlock(&vme_buses_lock);
+
 	driver_unregister(&drv->driver);
 }
 EXPORT_SYMBOL(vme_unregister_driver);
 
 /* - Bus Registration ------------------------------------------------------ */
 
-static struct vme_driver *dev_to_vme_driver(struct device *dev)
-{
-	if (dev->driver == NULL)
-		printk(KERN_ERR "Bugger dev->driver is NULL\n");
-
-	return container_of(dev->driver, struct vme_driver, driver);
-}
-
 static int vme_bus_match(struct device *dev, struct device_driver *drv)
 {
-	struct vme_dev *vdev;
-	struct vme_bridge *bridge;
-	struct vme_driver *driver;
-	int i, num;
-
-	vdev = dev_to_vme_dev(dev);
-	bridge = vdev->bridge;
-	driver = container_of(drv, struct vme_driver, driver);
+	struct vme_driver *vme_drv;
 
-	num = vdev->id.slot;
-	if (num <= 0 || num >= VME_SLOTS_MAX)
-		goto err_dev;
-
-	if (driver->bind_table == NULL) {
-		dev_err(dev, "Bind table NULL\n");
-		goto err_table;
-	}
+	vme_drv = container_of(drv, struct vme_driver, driver);
 
-	i = 0;
-	while ((driver->bind_table[i].bus != 0) ||
-		(driver->bind_table[i].slot != 0)) {
+	if (dev->platform_data == vme_drv) {
+		struct vme_dev *vdev = dev_to_vme_dev(dev);
 
-		if (bridge->num == driver->bind_table[i].bus) {
-			if (num == driver->bind_table[i].slot)
-				return 1;
+		if (vme_drv->match && vme_drv->match(vdev))
+			return 1;
 
-			if (driver->bind_table[i].slot == VME_SLOT_ALL)
-				return 1;
-
-			if ((driver->bind_table[i].slot == VME_SLOT_CURRENT) &&
-				(num == vme_slot_get(vdev)))
-				return 1;
-		}
-		i++;
+		dev->platform_data = NULL;
 	}
-
-err_dev:
-err_table:
 	return 0;
 }
 
 static int vme_bus_probe(struct device *dev)
 {
-	struct vme_driver *driver;
-	struct vme_dev *vdev;
 	int retval = -ENODEV;
+	struct vme_driver *driver;
+	struct vme_dev *vdev = dev_to_vme_dev(dev);
 
-	driver = dev_to_vme_driver(dev);
-	vdev = dev_to_vme_dev(dev);
+	driver = dev->platform_data;
 
 	if (driver->probe != NULL)
 		retval = driver->probe(vdev);
@@ -1498,12 +1507,11 @@ static int vme_bus_probe(struct device *dev)
 
 static int vme_bus_remove(struct device *dev)
 {
-	struct vme_driver *driver;
-	struct vme_dev *vdev;
 	int retval = -ENODEV;
+	struct vme_driver *driver;
+	struct vme_dev *vdev = dev_to_vme_dev(dev);
 
-	driver = dev_to_vme_driver(dev);
-	vdev = dev_to_vme_dev(dev);
+	driver = dev->platform_data;
 
 	if (driver->remove != NULL)
 		retval = driver->remove(vdev);