bus: attach / detach API

index 8f9baf8..5e33129 100644
@@ -145,3 +145,17 @@ rte_bus_dump(FILE *f)
 		}
 	}
 }
+
+struct rte_bus *
+rte_bus_find(int (*match)(const struct rte_bus *bus, const void *data),
+	const void *data)
+{
+	struct rte_bus *bus = NULL;
+
+	TAILQ_FOREACH(bus, &rte_bus_list, next) {
+		if (match(bus, data))
+			break;
+	}
+
+	return bus;
+}

index 7c36969..66856bb 100644
@@ -141,6 +141,26 @@ int rte_bus_probe(void);
 void rte_bus_dump(FILE *f);
 
 /**
+ * Bus iterator to find a particular bus.
+ *
+ * The callback function should return 0 if the bus doesn't match and non-zero
+ * if it does. If the callback returns non-zero this function will stop
+ * iterating over any more buses.
+ *
+ * @param match
+ *	 Callback function to check bus
+ *
+ * @param data
+ *	 Data to pass to match callback
+ *
+ * @return
+ *	 A pointer to a rte_bus structure or NULL in case no bus matches
+ */
+struct rte_bus *rte_bus_find(
+	int (*match)(const struct rte_bus *bus, const void *data),
+	const void *data);
+
+/**
  * Helper for Bus registration.
  * The constructor has higher priority than PMD constructors.
  */

index 5e33129..41926fb 100644
@@ -50,6 +50,7 @@ rte_bus_register(struct rte_bus *bus)
 	/* A bus should mandatorily have the scan implemented */
 	RTE_VERIFY(bus->scan);
 	RTE_VERIFY(bus->probe);
+	RTE_VERIFY(bus->find_device);
 
 	TAILQ_INSERT_TAIL(&rte_bus_list, bus, next);
 	RTE_LOG(DEBUG, EAL, "Registered [%s] bus.\n", bus->name);

index 66856bb..fe31f03 100644
@@ -82,6 +82,13 @@ typedef int (*rte_bus_scan_t)(void);
 typedef int (*rte_bus_probe_t)(void);
 
 /**
+ * Device iterator to find a particular device on a bus.
+ */
+typedef struct rte_device * (*rte_bus_find_device_t)(
+	int (*match)(const struct rte_device *dev, const void *data),
+	const void *data);
+
+/**
  * A structure describing a generic bus.
  */
 struct rte_bus {

@@ -89,6 +96,7 @@ struct rte_bus {
 	const char *name;            /**< Name of the bus */
 	rte_bus_scan_t scan;         /**< Scan for devices attached to bus */
 	rte_bus_probe_t probe;       /**< Probe devices on bus */
+	rte_bus_find_device_t find_device; /**< Find device on bus */
 };
 
 /**

index 41926fb..97bcd65 100644
@@ -160,3 +160,25 @@ rte_bus_find(int (*match)(const struct rte_bus *bus, const void *data),
 
 	return bus;
 }
+
+static int
+cmp_rte_device(const struct rte_device *dev, const void *_dev2)
+{
+	const struct rte_device *dev2 = _dev2;
+
+	return dev == dev2;
+}
+
+static int
+bus_find_device(const struct rte_bus *bus, const void *_dev)
+{
+	struct rte_device *dev;
+
+	dev = bus->find_device(cmp_rte_device, _dev);
+	return !!dev;
+}
+
+struct rte_bus *rte_bus_find_by_device(const struct rte_device *dev)
+{
+	return rte_bus_find(bus_find_device, (const void *)dev);
+}

index fe31f03..1707a1f 100644
@@ -169,6 +169,11 @@ struct rte_bus *rte_bus_find(
 	const void *data);
 
 /**
+ * Find the registered bus for a particular device.
+ */
+struct rte_bus *rte_bus_find_by_device(const struct rte_device *dev);
+
+/**
  * Helper for Bus registration.
  * The constructor has higher priority than PMD constructors.
  */

index 97bcd65..b8f8384 100644
@@ -182,3 +182,29 @@ struct rte_bus *rte_bus_find_by_device(const struct rte_device *dev)
 {
 	return rte_bus_find(bus_find_device, (const void *)dev);
 }
+
+struct rte_device *
+rte_bus_find_device(const struct rte_device *start,
+	int (*match)(const struct rte_device *dev, const void *data),
+	const void *data)
+{
+	struct rte_bus *bus;
+	struct rte_device *dev = NULL;
+
+	if (start) {
+		bus = rte_bus_find_by_device(start);
+		if (!bus)
+			return NULL;
+	} else
+		bus = TAILQ_FIRST(&rte_bus_list);
+
+	while (bus) {
+		dev = bus->find_device(match, data);
+		if (dev)
+			break;
+
+		TAILQ_NEXT(bus, next);
+	}
+
+	return dev;
+}

index 1707a1f..3b22fb8 100644
@@ -169,6 +169,32 @@ struct rte_bus *rte_bus_find(
 	const void *data);
 
 /**
+ * Bus iterator to find a particular device.
+ *
+ * The callback function should return 0 if the device doesn't match and
+ * non-zero if it does. If the callback returns non-zero this function will
+ * stop iterating over any more buses and devices.
+ * To continue a search the device of a previous search is passed via the start
+ * parameters.
+ *
+ * @param start
+ *	 Start device of the iteration
+ *
+ * @param match
+ *	 Callback function to check device
+ *
+ * @param data
+ *	 Data to pass to match callback
+ *
+ * @return
+ *	 A pointer to a rte_bus structure or NULL in case no bus matches
+ */
+struct rte_device *
+rte_bus_find_device(const struct rte_device *start,
+	int (*match)(const struct rte_device *dev, const void *data),
+	const void *data);
+
+/**
  * Find the registered bus for a particular device.
  */
 struct rte_bus *rte_bus_find_by_device(const struct rte_device *dev);

index b8f8384..9fda287 100644
@@ -52,6 +52,9 @@ rte_bus_register(struct rte_bus *bus)
 	RTE_VERIFY(bus->probe);
 	RTE_VERIFY(bus->find_device);
 
+	/* Buses supporting attach also require detach */
+	RTE_VERIFY(!bus->attach || bus->detach);
+
 	TAILQ_INSERT_TAIL(&rte_bus_list, bus, next);
 	RTE_LOG(DEBUG, EAL, "Registered [%s] bus.\n", bus->name);
 }

index 3b22fb8..201b0ff 100644
@@ -89,6 +89,20 @@ typedef struct rte_device * (*rte_bus_find_device_t)(
 	const void *data);
 
 /**
+ * Implementation specific probe function which is responsible for linking
+ * devices on that bus with applicable drivers.
+ *
+ */
+typedef int (*rte_bus_attach_t)(struct rte_device *dev);
+
+/**
+ * Implementation specific remove function which is responsible for unlinking
+ * devices on that bus from assigned driver.
+ *
+ */
+typedef int (*rte_bus_detach_t)(struct rte_device *dev);
+
+/**
  * A structure describing a generic bus.
  */
 struct rte_bus {

@@ -97,6 +111,8 @@ struct rte_bus {
 	rte_bus_scan_t scan;         /**< Scan for devices attached to bus */
 	rte_bus_probe_t probe;       /**< Probe devices on bus */
 	rte_bus_find_device_t find_device; /**< Find device on bus */
+	rte_bus_attach_t attach;     /**< Probe single device for drivers */
+	rte_bus_detach_t detach;     /**< Remove single device from driver */
 };
 
 /**

index 0037a64..5fc516f 100644
@@ -338,9 +338,24 @@ vdev_probe(void)
 	return 0;
 }
 
+static struct rte_device *
+vdev_find_device(int (*match)(const struct rte_device *dev, const void *data),
+	const void *data)
+{
+	struct rte_vdev_device *dev;
+
+	TAILQ_FOREACH(dev, &vdev_device_list, next) {
+		if (match(&dev->device, data))
+			return &dev->device;
+	}
+
+	return NULL;
+}
+
 static struct rte_bus rte_vdev_bus = {
 	.scan = vdev_scan,
 	.probe = vdev_probe,
+	.find_device = vdev_find_device,
 };
 
 RTE_INIT(rte_vdev_bus_register);

index 5fc516f..2095b01 100644
@@ -352,10 +352,22 @@ vdev_find_device(int (*match)(const struct rte_device *dev, const void *data),
 	return NULL;
 }
 
+static int
+vdev_detach(struct rte_device *dev)
+{
+	/*
+	 * The virtual bus doesn't support 'unattached' devices so this is
+	 * actually equal to hotplugging removal of it.
+	 */
+	return rte_vdev_uninit(dev->name);
+}
+
 static struct rte_bus rte_vdev_bus = {
 	.scan = vdev_scan,
 	.probe = vdev_probe,
 	.find_device = vdev_find_device,
+	/* .attach = NULL, see comment on vdev_detach */
+	.detach = vdev_detach,
 };
 
 RTE_INIT(rte_vdev_bus_register);

index a400ddd..c2d0f8d 100644
@@ -37,6 +37,7 @@
 #include <inttypes.h>
 #include <sys/queue.h>
 
+#include <rte_bus.h>
 #include <rte_dev.h>
 #include <rte_devargs.h>
 #include <rte_debug.h>

@@ -45,50 +46,98 @@
 
 #include "eal_private.h"
 
+static int cmp_detached_dev_name(const struct rte_device *dev,
+	const void *_name)
+{
+	const char *name = _name;
+
+	/* skip attached devices */
+	if (dev->driver)
+		return 0;
+
+	return !strcmp(dev->name, name);
+}
+
 int rte_eal_dev_attach(const char *name, const char *devargs)
 {
-	struct rte_pci_addr addr;
+	struct rte_device *dev;
+	int ret;
 
 	if (name == NULL || devargs == NULL) {
 		RTE_LOG(ERR, EAL, "Invalid device or arguments provided\n");
 		return -EINVAL;
 	}
 
-	if (eal_parse_pci_DomBDF(name, &addr) == 0) {
-		if (rte_pci_probe_one(&addr) < 0)
-			goto err;
+	dev = rte_bus_find_device(NULL, cmp_detached_dev_name, name);
+	if (dev) {
+		struct rte_bus *bus;
+
+		bus = rte_bus_find_by_device(dev);
+		if (!bus) {
+			RTE_LOG(ERR, EAL, "Cannot find bus for device (%s)\n",
+				name);
+			return -EINVAL;
+		}
 
-	} else {
-		if (rte_vdev_init(name, devargs))
-			goto err;
+		if (!bus->attach) {
+			RTE_LOG(ERR, EAL, "Bus function not supported\n");
+			return -ENOTSUP;
+		}
+
+		ret = bus->attach(dev);
+		goto out;
 	}
 
-	return 0;
+	/*
+	 * If we haven't found a bus device the user meant to "hotplug" a
+	 * virtual device instead.
+	 */
+	ret = rte_vdev_init(name, devargs);
+out:
+	if (ret)
+		RTE_LOG(ERR, EAL, "Driver cannot attach the device (%s)\n",
+			name);
+	return ret;
+}
+
+static int cmp_dev_name(const struct rte_device *dev, const void *_name)
+{
+	const char *name = _name;
 
-err:
-	RTE_LOG(ERR, EAL, "Driver cannot attach the device (%s)\n", name);
-	return -EINVAL;
+	return !strcmp(dev->name, name);
 }
 
 int rte_eal_dev_detach(const char *name)
 {
-	struct rte_pci_addr addr;
+	struct rte_device *dev;
+	struct rte_bus *bus;
+	int ret;
 
 	if (name == NULL) {
 		RTE_LOG(ERR, EAL, "Invalid device provided.\n");
 		return -EINVAL;
 	}
 
-	if (eal_parse_pci_DomBDF(name, &addr) == 0) {
-		if (rte_pci_detach(&addr) < 0)
-			goto err;
-	} else {
-		if (rte_vdev_uninit(name))
-			goto err;
+	dev = rte_bus_find_device(NULL, cmp_dev_name, name);
+	if (!dev) {
+		RTE_LOG(ERR, EAL, "Cannot find device (%s)\n", name);
+		return -EINVAL;
+	}
+
+	bus = rte_bus_find_by_device(dev);
+	if (!bus) {
+		RTE_LOG(ERR, EAL, "Cannot find bus for device (%s)\n", name);
+		return -EINVAL;
+	}
+
+	if (!bus->detach) {
+		RTE_LOG(ERR, EAL, "Bus function not supported\n");
+		return -ENOTSUP;
 	}
-	return 0;
 
-err:
-	RTE_LOG(ERR, EAL, "Driver cannot detach the device (%s)\n", name);
-	return -EINVAL;
+	ret = bus->detach(dev);
+	if (ret)
+		RTE_LOG(ERR, EAL, "Driver cannot detach the device (%s)\n",
+			name);
+	return ret;
 }

59 lines not on this page · raw message

index de20c06..7092b16 100644
@@ -123,6 +123,17 @@ struct rte_mem_resource {
 	void *addr;         /**< Virtual address, NULL when not mapped. */
 };
 
+/* FIXME: Forward declare */
+struct rte_device;
+
+/**
+ * Unplug the device from the device driver.
+ *
+ * @param dev
+ *   A pointer to a rte_device structure.
+ */
+int rte_eal_device_detach(struct rte_device *dev);
+
 /**
  * A structure describing a device driver.
  */

index 83898a8..ff4f5ab 100644
@@ -440,7 +440,8 @@ rte_eth_dev_detach(uint8_t port_id, char *name)
 
 	snprintf(name, sizeof(rte_eth_devices[port_id].data->name),
 		 "%s", rte_eth_devices[port_id].data->name);
-	ret = rte_eal_dev_detach(name);
+
+	ret = rte_eal_device_detach(rte_eth_devices[0].device);
 	if (ret < 0)
 		goto err;
 

index 8f9baf8..68f70d0 100644
@@ -145,3 +145,16 @@ rte_bus_dump(FILE *f)
 		}
 	}
 }
+
+struct rte_bus *
+rte_bus_find(rte_bus_match_t match, const void *data)
+{
+	struct rte_bus *bus = NULL;
+
+	TAILQ_FOREACH(bus, &rte_bus_list, next) {
+		if (match(bus, data))
+			break;
+	}
+
+	return bus;
+}

index 7c36969..006feca 100644
@@ -141,6 +141,38 @@ int rte_bus_probe(void);
 void rte_bus_dump(FILE *f);
 
 /**
+ * Bus match function.
+ *
+ * @param bus
+ *	bus under test.
+ *
+ * @param data
+ *	data matched
+ *
+ * @return
+ *	0 if the bus does not match.
+ *	!0 if the bus matches.
+ */
+typedef int (*rte_bus_match_t)(const struct rte_bus *bus, const void *data);
+
+/**
+ * Bus iterator to find a particular bus.
+ *
+ * If the callback returns non-zero this function will stop iterating over
+ * any more buses.
+ *
+ * @param match
+ *	 Callback function to check bus
+ *
+ * @param data
+ *	 Data to pass to match callback
+ *
+ * @return
+ *	 A pointer to a rte_bus structure or NULL in case no bus matches
+ */
+struct rte_bus *rte_bus_find(rte_bus_match_t match, const void *data);
+
+/**
  * Helper for Bus registration.
  * The constructor has higher priority than PMD constructors.
  */

index 006feca..4545b03 100644
@@ -82,6 +82,12 @@ typedef int (*rte_bus_scan_t)(void);
 typedef int (*rte_bus_probe_t)(void);
 
 /**
+ * Device iterator to find a particular device on a bus.
+ */
+typedef struct rte_device * (*rte_bus_find_device_t)(rte_dev_match_t match,
+						     const void *data);
+
+/**
  * A structure describing a generic bus.
  */
 struct rte_bus {

@@ -89,6 +95,7 @@ struct rte_bus {
 	const char *name;            /**< Name of the bus */
 	rte_bus_scan_t scan;         /**< Scan for devices attached to bus */
 	rte_bus_probe_t probe;       /**< Probe devices on bus */
+	rte_bus_find_device_t find_device; /**< Find device on bus */
 };
 
 /**

index de20c06..f017814 100644
@@ -191,6 +191,21 @@ int rte_eal_dev_attach(const char *name, const char *devargs);
  */
 int rte_eal_dev_detach(const char *name);
 
+/**
+ * Device match function.
+ *
+ * @param dev
+ *   Device handle.
+ *
+ * @param data
+ *   Data to match against.
+ *
+ * @return
+ *   0 if the device does not match.
+ *   !0 otherwise.
+ */
+typedef int (*rte_dev_match_t)(const struct rte_device *dev, const void *data);
+
 #define RTE_PMD_EXPORT_NAME_ARRAY(n, idx) n##idx[]
 
 #define RTE_PMD_EXPORT_NAME(name, idx) \

index 68f70d0..811aff3 100644
@@ -158,3 +158,27 @@ rte_bus_find(rte_bus_match_t match, const void *data)
 
 	return bus;
 }
+
+static int
+cmp_rte_device(const struct rte_device *dev, const void *_dev2)
+{
+	const struct rte_device *dev2 = _dev2;
+
+	return dev == dev2;
+}
+
+static int
+bus_find_device(const struct rte_bus *bus, const void *_dev)
+{
+	struct rte_device *dev;
+
+	if (!bus->find_device)
+		return 0;
+	dev = bus->find_device(cmp_rte_device, _dev);
+	return !!dev;
+}
+
+struct rte_bus *rte_bus_find_by_device(const struct rte_device *dev)
+{
+	return rte_bus_find(bus_find_device, (const void *)dev);
+}

index 4545b03..0664662 100644
@@ -180,6 +180,11 @@ typedef int (*rte_bus_match_t)(const struct rte_bus *bus, const void *data);
 struct rte_bus *rte_bus_find(rte_bus_match_t match, const void *data);
 
 /**
+ * Find the registered bus for a particular device.
+ */
+struct rte_bus *rte_bus_find_by_device(const struct rte_device *dev);
+
+/**
  * Helper for Bus registration.
  * The constructor has higher priority than PMD constructors.
  */

index 811aff3..632a6e7 100644
@@ -182,3 +182,28 @@ struct rte_bus *rte_bus_find_by_device(const struct rte_device *dev)
 {
 	return rte_bus_find(bus_find_device, (const void *)dev);
 }
+
+struct rte_device *
+rte_bus_find_device(const struct rte_device *start,
+		    rte_dev_match_t match, const void *data)
+{
+	struct rte_bus *bus;
+	struct rte_device *dev = NULL;
+	int start_seen = 0;
+
+	TAILQ_FOREACH(bus, &rte_bus_list, next) {
+		if (!bus->find_device)
+			continue;
+		if (!!start ^ start_seen) {
+			dev = bus->find_device(cmp_rte_device, start);
+			if (dev)
+				start_seen = 1;
+			else
+				continue;
+		}
+		dev = bus->find_device(match, data);
+		if (dev)
+			break;
+	}
+	return dev;
+}

index 0664662..b56018f 100644
@@ -180,6 +180,29 @@ typedef int (*rte_bus_match_t)(const struct rte_bus *bus, const void *data);
 struct rte_bus *rte_bus_find(rte_bus_match_t match, const void *data);
 
 /**
+ * Bus iterator to find a particular device.
+ *
+ * If the callback returns non-zero this function will stop iterating over any
+ * more buses and devices. To continue a search the device of a previous search
+ * is passed via the start parameters.
+ *
+ * @param start
+ *	 Start device of the iteration
+ *
+ * @param match
+ *	 Callback function to check device
+ *
+ * @param data
+ *	 Data to pass to match callback
+ *
+ * @return
+ *	 A pointer to a rte_bus structure or NULL in case no bus matches
+ */
+struct rte_device *
+rte_bus_find_device(const struct rte_device *start,
+		    rte_dev_match_t match, const void *data);
+
+/**
  * Find the registered bus for a particular device.
  */
 struct rte_bus *rte_bus_find_by_device(const struct rte_device *dev);

index 632a6e7..4063897 100644
@@ -51,6 +51,9 @@ rte_bus_register(struct rte_bus *bus)
 	RTE_VERIFY(bus->scan);
 	RTE_VERIFY(bus->probe);
 
+	/* Buses supporting hotplug also require unplug */
+	RTE_VERIFY(!bus->plug || bus->unplug);
+
 	TAILQ_INSERT_TAIL(&rte_bus_list, bus, next);
 	RTE_LOG(DEBUG, EAL, "Registered [%s] bus.\n", bus->name);
 }

index b56018f..3c59fc2 100644
@@ -88,6 +88,24 @@ typedef struct rte_device * (*rte_bus_find_device_t)(rte_dev_match_t match,
 						     const void *data);
 
 /**
+ * Implementation specific probe function which is responsible for linking
+ * devices on that bus with applicable drivers.
+ * The plugged device might already have been used previously by the bus,
+ * in which case some buses might prefer to detect and re-use the relevant
+ * information pertaining to this device.
+ */
+typedef int (*rte_bus_plug_t)(struct rte_devargs *da);
+
+/**
+ * Implementation specific remove function which is responsible for unlinking
+ * devices on that bus from assigned driver.
+ * Some buses will expect the same device to be plugged-back in eventually.
+ * The decision to release the associated meta-data (full-fledged bus-specific
+ * device representation) is left to the discretion of the bus.
+ */
+typedef int (*rte_bus_unplug_t)(struct rte_devargs *da);
+
+/**
  * A structure describing a generic bus.
  */
 struct rte_bus {

@@ -96,6 +114,8 @@ struct rte_bus {
 	rte_bus_scan_t scan;         /**< Scan for devices attached to bus */
 	rte_bus_probe_t probe;       /**< Probe devices on bus */
 	rte_bus_find_device_t find_device; /**< Find device on bus */
+	rte_bus_plug_t plug;         /**< Probe single device for drivers */
+	rte_bus_unplug_t unplug;     /**< Remove single device from driver */
 };
 
 /**

index 0037a64..46f2b74 100644
@@ -338,9 +338,22 @@ vdev_probe(void)
 	return 0;
 }
 
+static struct rte_device *
+vdev_find_device(rte_dev_match_t match, const void *data)
+{
+	struct rte_vdev_device *dev;
+
+	TAILQ_FOREACH(dev, &vdev_device_list, next) {
+		if (match(&dev->device, data))
+			return &dev->device;
+	}
+	return NULL;
+}
+
 static struct rte_bus rte_vdev_bus = {
 	.scan = vdev_scan,
 	.probe = vdev_probe,
+	.find_device = vdev_find_device,
 };
 
 RTE_INIT(rte_vdev_bus_register);

index 46f2b74..813955e 100644
@@ -350,10 +350,17 @@ vdev_find_device(rte_dev_match_t match, const void *data)
 	return NULL;
 }
 
+static int
+vdev_plug(struct rte_devargs *da)
+{
+	return rte_vdev_init(da->virt.drv_name, da->args);
+}
+
 static struct rte_bus rte_vdev_bus = {
 	.scan = vdev_scan,
 	.probe = vdev_probe,
 	.find_device = vdev_find_device,
+	.plug = vdev_plug,
 };
 
 RTE_INIT(rte_vdev_bus_register);

index 813955e..67c6fff 100644
@@ -356,11 +356,18 @@ vdev_plug(struct rte_devargs *da)
 	return rte_vdev_init(da->virt.drv_name, da->args);
 }
 
+static int
+vdev_unplug(struct rte_devargs *da)
+{
+	return rte_vdev_uninit(da->virt.drv_name);
+}
+
 static struct rte_bus rte_vdev_bus = {
 	.scan = vdev_scan,
 	.probe = vdev_probe,
 	.find_device = vdev_find_device,
 	.plug = vdev_plug,
+	.unplug = vdev_unplug,
 };
 
 RTE_INIT(rte_vdev_bus_register);

index a400ddd..7508b70 100644
@@ -37,6 +37,7 @@
 #include <inttypes.h>
 #include <sys/queue.h>
 
+#include <rte_bus.h>
 #include <rte_dev.h>
 #include <rte_devargs.h>
 #include <rte_debug.h>

@@ -45,50 +46,98 @@
 
 #include "eal_private.h"
 
+static int cmp_detached_dev_name(const struct rte_device *dev,
+	const void *_name)
+{
+	const char *name = _name;
+
+	/* skip attached devices */
+	if (dev->driver)
+		return 0;
+
+	return !strcmp(dev->name, name);
+}
+
 int rte_eal_dev_attach(const char *name, const char *devargs)
 {
-	struct rte_pci_addr addr;
+	struct rte_device *dev;
+	int ret;
 
 	if (name == NULL || devargs == NULL) {
 		RTE_LOG(ERR, EAL, "Invalid device or arguments provided\n");
 		return -EINVAL;
 	}
 
-	if (eal_parse_pci_DomBDF(name, &addr) == 0) {
-		if (rte_pci_probe_one(&addr) < 0)
-			goto err;
+	dev = rte_bus_find_device(NULL, cmp_detached_dev_name, name);
+	if (dev) {
+		struct rte_bus *bus;
+
+		bus = rte_bus_find_by_device(dev);
+		if (!bus) {
+			RTE_LOG(ERR, EAL, "Cannot find bus for device (%s)\n",
+				name);
+			return -EINVAL;
+		}
 
-	} else {
-		if (rte_vdev_init(name, devargs))
-			goto err;
+		if (!bus->plug) {
+			RTE_LOG(ERR, EAL, "Bus function not supported\n");
+			return -ENOTSUP;
+		}
+
+		ret = bus->plug(dev->devargs);
+		goto out;
 	}
 
-	return 0;
+	/*
+	 * If we haven't found a bus device the user meant to "hotplug" a
+	 * virtual device instead.
+	 */
+	ret = rte_vdev_init(name, devargs);
+out:
+	if (ret)
+		RTE_LOG(ERR, EAL, "Driver cannot attach the device (%s)\n",
+			name);
+	return ret;
+}
+
+static int cmp_dev_name(const struct rte_device *dev, const void *_name)
+{
+	const char *name = _name;
 
-err:
-	RTE_LOG(ERR, EAL, "Driver cannot attach the device (%s)\n", name);
-	return -EINVAL;
+	return !strcmp(dev->name, name);
 }
 
 int rte_eal_dev_detach(const char *name)
 {
-	struct rte_pci_addr addr;
+	struct rte_device *dev;
+	struct rte_bus *bus;
+	int ret;
 
 	if (name == NULL) {
 		RTE_LOG(ERR, EAL, "Invalid device provided.\n");
 		return -EINVAL;
 	}
 
-	if (eal_parse_pci_DomBDF(name, &addr) == 0) {
-		if (rte_pci_detach(&addr) < 0)
-			goto err;
-	} else {
-		if (rte_vdev_uninit(name))
-			goto err;
+	dev = rte_bus_find_device(NULL, cmp_dev_name, name);
+	if (!dev) {
+		RTE_LOG(ERR, EAL, "Cannot find device (%s)\n", name);
+		return -EINVAL;
+	}
+
+	bus = rte_bus_find_by_device(dev);
+	if (!bus) {
+		RTE_LOG(ERR, EAL, "Cannot find bus for device (%s)\n", name);
+		return -EINVAL;
+	}
+
+	if (!bus->unplug) {
+		RTE_LOG(ERR, EAL, "Bus function not supported\n");
+		return -ENOTSUP;
 	}
-	return 0;
 
-err:
-	RTE_LOG(ERR, EAL, "Driver cannot detach the device (%s)\n", name);
-	return -EINVAL;
+	ret = bus->unplug(dev->devargs);
+	if (ret)
+		RTE_LOG(ERR, EAL, "Driver cannot detach the device (%s)\n",
+			name);
+	return ret;
 }

59 lines not on this page · raw message

index f017814..c530797 100644
@@ -123,6 +123,17 @@ struct rte_mem_resource {
 	void *addr;         /**< Virtual address, NULL when not mapped. */
 };
 
+/* FIXME: Forward declare */
+struct rte_device;
+
+/**
+ * Unplug the device from the device driver.
+ *
+ * @param dev
+ *   A pointer to a rte_device structure.
+ */
+int rte_eal_device_detach(struct rte_device *dev);
+
 /**
  * A structure describing a device driver.
  */

index 83898a8..ff4f5ab 100644
@@ -440,7 +440,8 @@ rte_eth_dev_detach(uint8_t port_id, char *name)
 
 	snprintf(name, sizeof(rte_eth_devices[port_id].data->name),
 		 "%s", rte_eth_devices[port_id].data->name);
-	ret = rte_eal_dev_detach(name);
+
+	ret = rte_eal_device_detach(rte_eth_devices[0].device);
 	if (ret < 0)
 		goto err;
 

index 87d2258..9ebc60e 100644
@@ -515,6 +515,8 @@ rte_pmd_ring_probe(struct rte_vdev_device *dev)
 	RTE_LOG(INFO, PMD, "Initializing pmd_ring for %s\n", name);
 
 	if (params == NULL || params[0] == '\0') {
+		struct rte_eth_dev *eth_dev;
+
 		ret = eth_dev_ring_create(name, rte_socket_id(), DEV_CREATE);
 		if (ret == -1) {
 			RTE_LOG(INFO, PMD,

@@ -522,6 +524,11 @@ rte_pmd_ring_probe(struct rte_vdev_device *dev)
 			ret = eth_dev_ring_create(name, rte_socket_id(),
 						  DEV_ATTACH);
 		}
+		/* find an ethdev entry */
+		eth_dev = rte_eth_dev_allocated(name);
+		if (eth_dev == NULL)
+			return -ENODEV;
+		eth_dev->device = &dev->device;
 	}
 	else {
 		kvlist = rte_kvargs_parse(params, valid_arguments);

index 8f9baf8..a54aeb4 100644
@@ -145,3 +145,14 @@ rte_bus_dump(FILE *f)
 		}
 	}
 }
+
+struct rte_bus *
+rte_bus_find(rte_bus_cmp_t cmp, const void *data)
+{
+	struct rte_bus *bus = NULL;
+
+	TAILQ_FOREACH(bus, &rte_bus_list, next)
+		if (cmp(bus, data) == 0)
+			break;
+	return bus;
+}

index 7c36969..16bcfd9 100644
@@ -141,6 +141,40 @@ int rte_bus_probe(void);
 void rte_bus_dump(FILE *f);
 
 /**
+ * Bus comparison function.
+ *
+ * @param bus
+ *	Bus under test.
+ *
+ * @param data
+ *	Data to compare against.
+ *
+ * @return
+ *	0 if the bus matches the data.
+ *	!0 if the bus does not match.
+ *	<0 if ordering is possible and the bus is lower than the data.
+ *	>0 if ordering is possible and the bus is greater than the data.
+ */
+typedef int (*rte_bus_cmp_t)(const struct rte_bus *bus, const void *data);
+
+/**
+ * Bus iterator to find a particular bus.
+ *
+ * If the callback returns non-zero this function will stop iterating over
+ * any more buses.
+ *
+ * @param cmp
+ *	Comparison function.
+ *
+ * @param data
+ *	 Data to pass to cmp callback
+ *
+ * @return
+ *	 A pointer to a rte_bus structure or NULL in case no bus matches
+ */
+struct rte_bus *rte_bus_find(rte_bus_cmp_t cmp, const void *data);
+
+/**
  * Helper for Bus registration.
  * The constructor has higher priority than PMD constructors.
  */

index 16bcfd9..e3f867f 100644
@@ -82,6 +82,12 @@ typedef int (*rte_bus_scan_t)(void);
 typedef int (*rte_bus_probe_t)(void);
 
 /**
+ * Device iterator to find a particular device on a bus.
+ */
+typedef struct rte_device * (*rte_bus_find_device_t)(rte_dev_cmp_t match,
+						     const void *data);
+
+/**
  * A structure describing a generic bus.
  */
 struct rte_bus {

@@ -89,6 +95,7 @@ struct rte_bus {
 	const char *name;            /**< Name of the bus */
 	rte_bus_scan_t scan;         /**< Scan for devices attached to bus */
 	rte_bus_probe_t probe;       /**< Probe devices on bus */
+	rte_bus_find_device_t find_device; /**< Find device on bus */
 };
 
 /**

index de20c06..724855e 100644
@@ -191,6 +191,23 @@ int rte_eal_dev_attach(const char *name, const char *devargs);
  */
 int rte_eal_dev_detach(const char *name);
 
+/**
+ * Device comparison function.
+ *
+ * @param dev
+ *   Device handle.
+ *
+ * @param data
+ *   Data to compare against.
+ *
+ * @return
+ *   0 if the device matches the data.
+ *   !0 if the device does not match.
+ *   <0 if ordering is possible and the device is lower than the data.
+ *   >0 if ordering is possible and the device is greater than the data.
+ */
+typedef int (*rte_dev_cmp_t)(const struct rte_device *dev, const void *data);
+
 #define RTE_PMD_EXPORT_NAME_ARRAY(n, idx) n##idx[]
 
 #define RTE_PMD_EXPORT_NAME(name, idx) \

index a54aeb4..42f1076 100644
@@ -156,3 +156,27 @@ rte_bus_find(rte_bus_cmp_t cmp, const void *data)
 			break;
 	return bus;
 }
+
+static int
+cmp_rte_device(const struct rte_device *dev, const void *_dev2)
+{
+	const struct rte_device *dev2 = _dev2;
+
+	return !(dev == dev2);
+}
+
+static int
+bus_find_device(const struct rte_bus *bus, const void *_dev)
+{
+	struct rte_device *dev;
+
+	if (!bus->find_device)
+		return -1;
+	dev = bus->find_device(cmp_rte_device, _dev);
+	return !dev;
+}
+
+struct rte_bus *rte_bus_find_by_device(const struct rte_device *dev)
+{
+	return rte_bus_find(bus_find_device, (const void *)dev);
+}

index e3f867f..b3bc6e8 100644
@@ -182,6 +182,11 @@ typedef int (*rte_bus_cmp_t)(const struct rte_bus *bus, const void *data);
 struct rte_bus *rte_bus_find(rte_bus_cmp_t cmp, const void *data);
 
 /**
+ * Find the registered bus for a particular device.
+ */
+struct rte_bus *rte_bus_find_by_device(const struct rte_device *dev);
+
+/**
  * Helper for Bus registration.
  * The constructor has higher priority than PMD constructors.
  */

index 42f1076..451884f 100644
@@ -180,3 +180,28 @@ struct rte_bus *rte_bus_find_by_device(const struct rte_device *dev)
 {
 	return rte_bus_find(bus_find_device, (const void *)dev);
 }
+
+struct rte_device *
+rte_bus_find_device(const struct rte_device *start,
+		    rte_dev_cmp_t cmp, const void *data)
+{
+	struct rte_bus *bus;
+	struct rte_device *dev = NULL;
+	int start_seen = 0;
+
+	TAILQ_FOREACH(bus, &rte_bus_list, next) {
+		if (!bus->find_device)
+			continue;
+		if (!!start ^ start_seen) {
+			dev = bus->find_device(cmp_rte_device, start);
+			if (dev)
+				start_seen = 1;
+			else
+				continue;
+		}
+		dev = bus->find_device(cmp, data);
+		if (dev)
+			break;
+	}
+	return dev;
+}

index b3bc6e8..eba407d 100644
@@ -182,6 +182,29 @@ typedef int (*rte_bus_cmp_t)(const struct rte_bus *bus, const void *data);
 struct rte_bus *rte_bus_find(rte_bus_cmp_t cmp, const void *data);
 
 /**
+ * Bus iterator to find a particular device.
+ *
+ * If the callback returns non-zero this function will stop iterating over any
+ * more buses and devices. To continue a search the device of a previous search
+ * is passed via the start parameters.
+ *
+ * @param start
+ *	 Start device of the iteration.
+ *
+ * @param cmp
+ *	 Callback function to check device.
+ *
+ * @param data
+ *	 Data to pass to match callback.
+ *
+ * @return
+ *	 A pointer to a rte_bus structure or NULL in case no bus matches.
+ */
+struct rte_device *
+rte_bus_find_device(const struct rte_device *start,
+		    rte_dev_cmp_t cmp, const void *data);
+
+/**
  * Find the registered bus for a particular device.
  */
 struct rte_bus *rte_bus_find_by_device(const struct rte_device *dev);

index 451884f..381a0b6 100644
@@ -50,6 +50,8 @@ rte_bus_register(struct rte_bus *bus)
 	/* A bus should mandatorily have the scan implemented */
 	RTE_VERIFY(bus->scan);
 	RTE_VERIFY(bus->probe);
+	/* Buses supporting hotplug also require unplug. */
+	RTE_VERIFY(!bus->plug || bus->unplug);
 
 	TAILQ_INSERT_TAIL(&rte_bus_list, bus, next);
 	RTE_LOG(DEBUG, EAL, "Registered [%s] bus.\n", bus->name);

index eba407d..cb44e46 100644
@@ -88,6 +88,35 @@ typedef struct rte_device * (*rte_bus_find_device_t)(rte_dev_cmp_t match,
 						     const void *data);
 
 /**
+ * Implementation specific probe function which is responsible for linking
+ * devices on that bus with applicable drivers.
+ * The plugged device might already have been used previously by the bus,
+ * in which case some buses might prefer to detect and re-use the relevant
+ * information pertaining to this device.
+ *
+ * @param da
+ *	Device declaration.
+ *
+ * @return
+ *	The pointer to a valid rte_device usable by the bus on success.
+ *	NULL on error. rte_errno is then set.
+ */
+typedef struct rte_device * (*rte_bus_plug_t)(struct rte_devargs *da);
+
+/**
+ * Implementation specific remove function which is responsible for unlinking
+ * devices on that bus from assigned driver.
+ *
+ * @param dev
+ *	Device pointer that was returned by a previous device plug call.
+ *
+ * @return
+ *	0 on success.
+ *	!0 on error. rte_errno is then set.
+ */
+typedef int (*rte_bus_unplug_t)(struct rte_device *dev);
+
+/**
  * A structure describing a generic bus.
  */
 struct rte_bus {

@@ -96,6 +125,8 @@ struct rte_bus {
 	rte_bus_scan_t scan;         /**< Scan for devices attached to bus */
 	rte_bus_probe_t probe;       /**< Probe devices on bus */
 	rte_bus_find_device_t find_device; /**< Find device on bus */
+	rte_bus_plug_t plug;         /**< Probe single device for drivers */
+	rte_bus_unplug_t unplug;     /**< Remove single device from driver */
 };
 
 /**

index 0037a64..52528ef 100644
@@ -338,9 +338,22 @@ vdev_probe(void)
 	return 0;
 }
 
+static struct rte_device *
+vdev_find_device(rte_dev_cmp_t cmp, const void *data)
+{
+	struct rte_vdev_device *dev;
+
+	TAILQ_FOREACH(dev, &vdev_device_list, next) {
+		if (cmp(&dev->device, data) == 0)
+			return &dev->device;
+	}
+	return NULL;
+}
+
 static struct rte_bus rte_vdev_bus = {
 	.scan = vdev_scan,
 	.probe = vdev_probe,
+	.find_device = vdev_find_device,
 };
 
 RTE_INIT(rte_vdev_bus_register);

index 52528ef..22e4640 100644
@@ -38,11 +38,13 @@
 #include <sys/queue.h>
 
 #include <rte_eal.h>
+#include <rte_dev.h>
 #include <rte_bus.h>
 #include <rte_vdev.h>
 #include <rte_common.h>
 #include <rte_devargs.h>
 #include <rte_memory.h>
+#include <rte_errno.h>
 
 /** Double linked list of virtual device drivers. */
 TAILQ_HEAD(vdev_device_list, rte_vdev_device);

@@ -350,10 +352,44 @@ vdev_find_device(rte_dev_cmp_t cmp, const void *data)
 	return NULL;
 }
 
+static struct rte_device *
+vdev_plug(struct rte_devargs *da)
+{
+	struct rte_vdev_device *dev;
+	int ret;
+
+	ret = rte_vdev_init(da->virt.drv_name, da->args);
+	if (ret) {
+		rte_errno = -ret;
+		return NULL;
+	}
+	dev = find_vdev(da->virt.drv_name);
+	return &dev->device;
+}
+
+static int
+vdev_unplug(struct rte_device *dev)
+{
+	struct rte_devargs *da;
+	int ret;
+
+	da = dev->devargs;
+	if (da == NULL) {
+		rte_errno = EINVAL;
+		return -1;
+	}
+	ret = rte_vdev_uninit(da->virt.drv_name);
+	if (ret)
+		rte_errno = -ret;
+	return ret;
+}
+
 static struct rte_bus rte_vdev_bus = {
 	.scan = vdev_scan,
 	.probe = vdev_probe,
 	.find_device = vdev_find_device,
+	.plug = vdev_plug,
+	.unplug = vdev_unplug,
 };
 
 RTE_INIT(rte_vdev_bus_register);

index a400ddd..733da91 100644
@@ -37,6 +37,7 @@
 #include <inttypes.h>
 #include <sys/queue.h>
 
+#include <rte_bus.h>
 #include <rte_dev.h>
 #include <rte_devargs.h>
 #include <rte_debug.h>

@@ -45,50 +46,98 @@
 
 #include "eal_private.h"
 
+static int cmp_detached_dev_name(const struct rte_device *dev,
+	const void *_name)
+{
+	const char *name = _name;
+
+	/* skip attached devices */
+	if (dev->driver)
+		return 0;
+
+	return strcmp(dev->name, name);
+}
+
 int rte_eal_dev_attach(const char *name, const char *devargs)
 {
-	struct rte_pci_addr addr;
+	struct rte_device *dev;
+	int ret;
 
 	if (name == NULL || devargs == NULL) {
 		RTE_LOG(ERR, EAL, "Invalid device or arguments provided\n");
 		return -EINVAL;
 	}
 
-	if (eal_parse_pci_DomBDF(name, &addr) == 0) {
-		if (rte_pci_probe_one(&addr) < 0)
-			goto err;
+	dev = rte_bus_find_device(NULL, cmp_detached_dev_name, name);
+	if (dev) {
+		struct rte_bus *bus;
+
+		bus = rte_bus_find_by_device(dev);
+		if (!bus) {
+			RTE_LOG(ERR, EAL, "Cannot find bus for device (%s)\n",
+				name);
+			return -EINVAL;
+		}
 
-	} else {
-		if (rte_vdev_init(name, devargs))
-			goto err;
+		if (!bus->plug) {
+			RTE_LOG(ERR, EAL, "Bus function not supported\n");
+			return -ENOTSUP;
+		}
+
+		ret = (bus->plug(dev->devargs) == NULL);
+		goto out;
 	}
 
-	return 0;
+	/*
+	 * If we haven't found a bus device the user meant to "hotplug" a
+	 * virtual device instead.
+	 */
+	ret = rte_vdev_init(name, devargs);
+out:
+	if (ret)
+		RTE_LOG(ERR, EAL, "Driver cannot attach the device (%s)\n",
+			name);
+	return ret;
+}
+
+static int cmp_dev_name(const struct rte_device *dev, const void *_name)
+{
+	const char *name = _name;
 
-err:
-	RTE_LOG(ERR, EAL, "Driver cannot attach the device (%s)\n", name);
-	return -EINVAL;
+	return strcmp(dev->name, name);
 }
 
 int rte_eal_dev_detach(const char *name)
 {
-	struct rte_pci_addr addr;
+	struct rte_device *dev;
+	struct rte_bus *bus;
+	int ret;
 
 	if (name == NULL) {
 		RTE_LOG(ERR, EAL, "Invalid device provided.\n");
 		return -EINVAL;
 	}
 
-	if (eal_parse_pci_DomBDF(name, &addr) == 0) {
-		if (rte_pci_detach(&addr) < 0)
-			goto err;
-	} else {
-		if (rte_vdev_uninit(name))
-			goto err;
+	dev = rte_bus_find_device(NULL, cmp_dev_name, name);
+	if (!dev) {
+		RTE_LOG(ERR, EAL, "Cannot find device (%s)\n", name);
+		return -EINVAL;
+	}
+
+	bus = rte_bus_find_by_device(dev);
+	if (!bus) {
+		RTE_LOG(ERR, EAL, "Cannot find bus for device (%s)\n", name);
+		return -EINVAL;
+	}
+
+	if (!bus->unplug) {
+		RTE_LOG(ERR, EAL, "Bus function not supported\n");
+		return -ENOTSUP;
 	}
-	return 0;
 
-err:
-	RTE_LOG(ERR, EAL, "Driver cannot detach the device (%s)\n", name);
-	return -EINVAL;
+	ret = bus->unplug(dev);
+	if (ret)
+		RTE_LOG(ERR, EAL, "Driver cannot detach the device (%s)\n",
+			name);
+	return ret;
 }

59 lines not on this page · raw message

index 724855e..9f35b1f 100644
@@ -123,6 +123,17 @@ struct rte_mem_resource {
 	void *addr;         /**< Virtual address, NULL when not mapped. */
 };
 
+/* FIXME: Forward declare */
+struct rte_device;
+
+/**
+ * Unplug the device from the device driver.
+ *
+ * @param dev
+ *   A pointer to a rte_device structure.
+ */
+int rte_eal_device_detach(struct rte_device *dev);
+
 /**
  * A structure describing a device driver.
  */

index 606252f..bc603c1 100644
@@ -355,26 +355,14 @@ rte_eth_dev_get_port_by_name(const char *name, uint8_t *port_id)
 static int
 rte_eth_dev_is_detachable(uint8_t port_id)
 {
-	uint32_t dev_flags;
+	struct rte_eth_dev *dev;
 
 	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -EINVAL);
 
-	switch (rte_eth_devices[port_id].data->kdrv) {
-	case RTE_KDRV_IGB_UIO:
-	case RTE_KDRV_UIO_GENERIC:
-	case RTE_KDRV_NIC_UIO:
-	case RTE_KDRV_NONE:
-	case RTE_KDRV_VFIO:
-		break;
-	default:
-		return -ENOTSUP;
-	}
-	dev_flags = rte_eth_devices[port_id].data->dev_flags;
-	if ((dev_flags & RTE_ETH_DEV_DETACHABLE) &&
-		(!(dev_flags & RTE_ETH_DEV_BONDED_SLAVE)))
+	dev = &rte_eth_devices[port_id];
+	if (dev->data->dev_flags & RTE_ETH_DEV_BONDED_SLAVE)
 		return 0;
-	else
-		return 1;
+	return !!dev->device->devargs->bus->unplug;
 }
 
 /* attach the new device, then store port_id of the device */

@@ -427,6 +415,7 @@ rte_eth_dev_attach(const char *devargs, uint8_t *port_id)
 int
 rte_eth_dev_detach(uint8_t port_id, char *name)
 {
+	struct rte_eth_dev *dev;
 	int ret = -1;
 
 	if (name == NULL) {

@@ -435,15 +424,15 @@ rte_eth_dev_detach(uint8_t port_id, char *name)
 	}
 
 	/* FIXME: move this to eal, once device flags are relocated there */
-	if (rte_eth_dev_is_detachable(port_id))
+	if (!rte_eth_dev_is_detachable(port_id))
 		goto err;
 
-	snprintf(name, sizeof(rte_eth_devices[port_id].data->name),
-		 "%s", rte_eth_devices[port_id].data->name);
-	ret = rte_eal_dev_detach(name);
+	dev = &rte_eth_devices[port_id];
+	snprintf(name, RTE_ETH_NAME_MAX_LEN - 1, "%s", dev->device->name);
+	ret = rte_eal_device_detach(dev->device);
 	if (ret < 0)
 		goto err;
-
+	dev->state = RTE_ETH_DEV_UNUSED;
 	return 0;
 
 err:

index d4dce95..2cd32a9 100644
@@ -515,6 +515,8 @@ rte_pmd_ring_probe(struct rte_vdev_device *dev)
 	RTE_LOG(INFO, PMD, "Initializing pmd_ring for %s\n", name);
 
 	if (params == NULL || params[0] == '\0') {
+		struct rte_eth_dev *eth_dev;
+
 		ret = eth_dev_ring_create(name, rte_socket_id(), DEV_CREATE);
 		if (ret == -1) {
 			RTE_LOG(INFO, PMD,

@@ -522,6 +524,11 @@ rte_pmd_ring_probe(struct rte_vdev_device *dev)
 			ret = eth_dev_ring_create(name, rte_socket_id(),
 						  DEV_ATTACH);
 		}
+		/* find an ethdev entry */
+		eth_dev = rte_eth_dev_allocated(name);
+		if (eth_dev == NULL)
+			return -ENODEV;
+		eth_dev->device = &dev->device;
 	}
 	else {
 		kvlist = rte_kvargs_parse(params, valid_arguments);

index 8f9baf8..4619eb2 100644
@@ -145,3 +145,23 @@ rte_bus_dump(FILE *f)
 		}
 	}
 }
+
+struct rte_bus *
+rte_bus_find(rte_bus_cmp_t cmp,
+	     const void *data,
+	     const struct rte_bus *start)
+{
+	struct rte_bus *bus = NULL;
+	int started = start == NULL;
+
+	TAILQ_FOREACH(bus, &rte_bus_list, next) {
+		if (!started) {
+			if (bus == start)
+				started = 1;
+			continue;
+		}
+		if (cmp(bus, data) == 0)
+			break;
+	}
+	return bus;
+}

47 lines not on this page · raw message

index 3e26d4b..fe9573f 100644
@@ -82,6 +82,12 @@ typedef int (*rte_bus_scan_t)(void);
 typedef int (*rte_bus_probe_t)(void);
 
 /**
+ * Device iterator to find a particular device on a bus.
+ */
+typedef struct rte_device * (*rte_bus_find_device_t)(rte_dev_cmp_t match,
+						     const void *data);
+
+/**
  * A structure describing a generic bus.
  */
 struct rte_bus {

@@ -89,6 +95,7 @@ struct rte_bus {
 	const char *name;            /**< Name of the bus */
 	rte_bus_scan_t scan;         /**< Scan for devices attached to bus */
 	rte_bus_probe_t probe;       /**< Probe devices on bus */
+	rte_bus_find_device_t find_device; /**< Find device on bus */
 };
 
 /**

index de20c06..724855e 100644
@@ -191,6 +191,23 @@ int rte_eal_dev_attach(const char *name, const char *devargs);
  */
 int rte_eal_dev_detach(const char *name);
 
+/**
+ * Device comparison function.
+ *
+ * @param dev
+ *   Device handle.
+ *
+ * @param data
+ *   Data to compare against.
+ *
+ * @return
+ *   0 if the device matches the data.
+ *   !0 if the device does not match.
+ *   <0 if ordering is possible and the device is lower than the data.
+ *   >0 if ordering is possible and the device is greater than the data.
+ */
+typedef int (*rte_dev_cmp_t)(const struct rte_device *dev, const void *data);
+
 #define RTE_PMD_EXPORT_NAME_ARRAY(n, idx) n##idx[]
 
 #define RTE_PMD_EXPORT_NAME(name, idx) \