eal: add hotplug add/remove device

Signed-off-by: Jan Blunck <jblunck@infradead.org>

lib/librte_eal/bsdapp/eal/rte_eal_version.map

@@ -202,3 +202,11 @@ DPDK_17.08 {
 	rte_bus_find_by_name;
 
 } DPDK_17.05;
+
+EXPERIMENTAL {
+	global:
+
+	rte_eal_hotplug_add;
+	rte_eal_hotplug_remove;
+
+} DPDK_17.08;

lib/librte_eal/common/eal_common_dev.c

@@ -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>
@@ -45,6 +46,25 @@
 
 #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 != NULL)
+		return 1;
+
+	return strcmp(dev->name, name);
+}
+
+static int cmp_dev_name(const struct rte_device *dev, const void *_name)
+{
+	const char *name = _name;
+
+	return strcmp(dev->name, name);
+}
+
 int rte_eal_dev_attach(const char *name, const char *devargs)
 {
 	struct rte_pci_addr addr;
@@ -92,3 +112,71 @@ int rte_eal_dev_detach(const char *name)
 	RTE_LOG(ERR, EAL, "Driver cannot detach the device (%s)\n", name);
 	return -EINVAL;
 }
+
+int rte_eal_hotplug_add(const char *busname, const char *devname,
+			const char *devargs)
+{
+	struct rte_bus *bus;
+	struct rte_device *dev;
+	int ret;
+
+	bus = rte_bus_find_by_name(busname);
+	if (bus == NULL) {
+		RTE_LOG(ERR, EAL, "Cannot find bus (%s)\n", busname);
+		return -ENOENT;
+	}
+
+	if (bus->plug == NULL) {
+		RTE_LOG(ERR, EAL, "Function plug not supported by bus (%s)\n",
+			bus->name);
+		return -ENOTSUP;
+	}
+
+	ret = bus->scan();
+	if (ret)
+		return ret;
+
+	dev = bus->find_device(NULL, cmp_detached_dev_name, devname);
+	if (dev == NULL) {
+		RTE_LOG(ERR, EAL, "Cannot find unplugged device (%s)\n",
+			devname);
+		return -EINVAL;
+	}
+
+	ret = bus->plug(dev, devargs);
+	if (ret)
+		RTE_LOG(ERR, EAL, "Driver cannot attach the device (%s)\n",
+			dev->name);
+	return ret;
+}
+
+int rte_eal_hotplug_remove(const char *busname, const char *devname)
+{
+	struct rte_bus *bus;
+	struct rte_device *dev;
+	int ret;
+
+	bus = rte_bus_find_by_name(busname);
+	if (bus == NULL) {
+		RTE_LOG(ERR, EAL, "Cannot find bus (%s)\n", busname);
+		return -ENOENT;
+	}
+
+	if (bus->unplug == NULL) {
+		RTE_LOG(ERR, EAL, "Function unplug not supported by bus (%s)\n",
+			bus->name);
+		return -ENOTSUP;
+	}
+
+	dev = bus->find_device(NULL, cmp_dev_name, devname);
+	if (dev == NULL) {
+		RTE_LOG(ERR, EAL, "Cannot find plugged device (%s)\n", devname);
+		return -EINVAL;
+	}
+
+	ret = bus->unplug(dev);
+	if (ret)
+		RTE_LOG(ERR, EAL, "Driver cannot detach the device (%s)\n",
+			dev->name);
+	return ret;
+}

lib/librte_eal/common/include/rte_dev.h

@@ -191,6 +191,40 @@ int rte_eal_dev_attach(const char *name, const char *devargs);
  */
 int rte_eal_dev_detach(const char *name);
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Hotplug add a given device to a specific bus.
+ *
+ * @param busname
+ *   The bus name the device is added to.
+ * @param devname
+ *   The device name. Based on this device name, eal will identify a driver
+ *   capable of handling it and pass it to the driver probing function.
+ * @param devargs
+ *   Device arguments to be passed to the driver.
+ * @return
+ *   0 on success, negative on error.
+ */
+int rte_eal_hotplug_add(const char *busname, const char *devname,
+			const char *devargs);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Hotplug remove a given device from a specific bus.
+ *
+ * @param busname
+ *   The bus name the device is removed from.
+ * @param devname
+ *   The device name being removed.
+ * @return
+ *   0 on success, negative on error.
+ */
+int rte_eal_hotplug_remove(const char *busname, const char *devname);
+
 /**
  * Device comparison function.
  *

lib/librte_eal/linuxapp/eal/rte_eal_version.map

@@ -207,3 +207,11 @@ DPDK_17.08 {
 	rte_bus_find_by_name;
 
 } DPDK_17.05;
+
+EXPERIMENTAL {
+	global:
+
+	rte_eal_hotplug_add;
+	rte_eal_hotplug_remove;
+
+} DPDK_17.08;