[PATCH v9 12/12] eal: enable hotplugging of devices on bus

[Shreyansh Jain <shreyansh.jain@nxp.com>]

Given a bus, attach and detach callbacks allow the implementation to
handles calls from EAL for attaching or detaching a named device.

Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>
---
 lib/librte_eal/bsdapp/eal/eal_pci.c     |  2 +
 lib/librte_eal/common/eal_common_dev.c  | 56 ++++++++++++++++-----
 lib/librte_eal/common/eal_common_pci.c  | 89 +++++++++++++++++++++++++++++++--
 lib/librte_eal/common/include/rte_bus.h | 31 ++++++++++++
 lib/librte_eal/common/include/rte_pci.h | 45 +++++++++++------
 lib/librte_eal/linuxapp/eal/eal_pci.c   |  2 +
 6 files changed, 193 insertions(+), 32 deletions(-)

diff --git a/lib/librte_eal/bsdapp/eal/eal_pci.c b/lib/librte_eal/bsdapp/eal/eal_pci.c
index e0deded..7d7f90c 100644
--- a/lib/librte_eal/bsdapp/eal/eal_pci.c
+++ b/lib/librte_eal/bsdapp/eal/eal_pci.c
@@ -682,6 +682,8 @@ struct rte_pci_bus rte_pci_bus = {
 	.bus = {
 		.scan = rte_eal_pci_scan,
 		.probe = rte_eal_pci_probe,
+		.attach = rte_eal_pci_attach,
+		.detach = rte_eal_pci_detach,
 	},
 	.device_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.device_list),
 	.driver_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.driver_list),
diff --git a/lib/librte_eal/common/eal_common_dev.c b/lib/librte_eal/common/eal_common_dev.c
index 4f3b493..97d0cf5 100644
--- a/lib/librte_eal/common/eal_common_dev.c
+++ b/lib/librte_eal/common/eal_common_dev.c
@@ -38,6 +38,7 @@
 #include <sys/queue.h>
 
 #include <rte_dev.h>
+#include <rte_bus.h>
 #include <rte_devargs.h>
 #include <rte_debug.h>
 #include <rte_devargs.h>
@@ -106,23 +107,37 @@ rte_eal_dev_init(void)
 
 int rte_eal_dev_attach(const char *name, const char *devargs)
 {
-	struct rte_pci_addr addr;
+	int ret = 1;
+	struct rte_bus *bus;
 
 	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_eal_pci_probe_one(&addr) < 0)
+	FOREACH_BUS(bus) {
+		if (!bus->attach) {
+			RTE_LOG(DEBUG, EAL, "Bus (%s) doesn't implement"
+				" attach.\n", bus->name);
+			continue;
+		}
+		ret = bus->attach(name);
+		if (!ret) /* device successfully attached */
+			return ret;
+		if (ret > 0) /* device not found on bus */
+			continue;
+		else
 			goto err;
+	}
 
-	} else {
-		if (rte_eal_vdev_init(name, devargs))
+	if (ret > 0) {
+		/* In case the device was not found on any bus, search VDEV */
+		ret = rte_eal_vdev_init(name, devargs);
+		if (ret)
 			goto err;
 	}
 
-	return 0;
+	return ret;
 
 err:
 	RTE_LOG(ERR, EAL, "Driver cannot attach the device (%s)\n", name);
@@ -131,21 +146,38 @@ int rte_eal_dev_attach(const char *name, const char *devargs)
 
 int rte_eal_dev_detach(const char *name)
 {
-	struct rte_pci_addr addr;
+	int ret = 1;
+	struct rte_bus *bus;
 
 	if (name == NULL) {
 		RTE_LOG(ERR, EAL, "Invalid device provided.\n");
 		return -EINVAL;
 	}
 
-	if (eal_parse_pci_DomBDF(name, &addr) == 0) {
-		if (rte_eal_pci_detach(&addr) < 0)
+	FOREACH_BUS(bus) {
+		if (!bus->detach) {
+			RTE_LOG(DEBUG, EAL, "Bus (%s) doesn't implement"
+				" detach.\n", bus->name);
+			continue;
+		}
+
+		ret = bus->detach(name);
+		if (!ret) /* device successfully detached */
+			return ret;
+		if (ret > 0) /* device not found on the bus */
+			continue;
+		else
 			goto err;
-	} else {
-		if (rte_eal_vdev_uninit(name))
+	}
+
+	if (ret > 0) {
+		/* In case the device was not found on any bus, search VDEV */
+		ret = rte_eal_vdev_uninit(name);
+		if (ret)
 			goto err;
 	}
-	return 0;
+
+	return ret;
 
 err:
 	RTE_LOG(ERR, EAL, "Driver cannot detach the device (%s)\n", name);
diff --git a/lib/librte_eal/common/eal_common_pci.c b/lib/librte_eal/common/eal_common_pci.c
index a17ecaf..e4f37f3 100644
--- a/lib/librte_eal/common/eal_common_pci.c
+++ b/lib/librte_eal/common/eal_common_pci.c
@@ -364,19 +364,98 @@ rte_eal_pci_probe_one(const struct rte_pci_addr *addr)
 }
 
 /*
+ * Attach device specific by its name
+ */
+int
+rte_eal_pci_attach(const char *device_name)
+{
+	struct rte_pci_device *dev = NULL;
+	struct rte_pci_driver *drv = NULL;
+	struct rte_pci_addr addr;
+	int ret;
+
+	if (!device_name)
+		return -1;
+
+	memset(&addr, 0, sizeof(addr));
+	if (eal_parse_pci_DomBDF(device_name, &addr)) {
+		/* Device doesn't match PCI BDF naming format */
+		return 1;
+	}
+
+	if (pci_update_device(&addr) < 0)
+		goto err_return;
+
+	FOREACH_DEVICE_ON_PCIBUS(dev) {
+		if (rte_eal_compare_pci_addr(&dev->addr, &addr))
+			continue;
+
+		FOREACH_DRIVER_ON_PCIBUS(drv) {
+			ret = rte_pci_match(drv, dev);
+			if (ret) {
+				/* Match of device and driver failed */
+				RTE_LOG(DEBUG, EAL, "Driver (%s) doesn't match"
+					" the device (%s)\n", drv->driver.name,
+					device_name);
+				continue;
+			}
+
+			RTE_LOG(INFO, EAL, "  probe driver: %x:%x %s\n",
+				dev->id.vendor_id, dev->id.device_id,
+				drv->driver.name);
+
+			if (drv->drv_flags & RTE_PCI_DRV_NEED_MAPPING) {
+				/* map resources for devices that use
+				 * igb_uio
+				 */
+				ret = rte_eal_pci_map_device(dev);
+				if (ret != 0)
+					goto err_return;
+			}
+
+			/* reference driver structure */
+			dev->driver = drv;
+
+			/* call the driver probe() function */
+			ret = drv->probe(drv, dev);
+			if (ret) {
+				dev->driver = NULL;
+				if (drv->drv_flags & RTE_PCI_DRV_NEED_MAPPING)
+					rte_eal_pci_unmap_device(dev);
+			}
+			return ret;
+		}
+	}
+
+	return 1;
+err_return:
+	RTE_LOG(WARNING, EAL, "Requested device " PCI_PRI_FMT
+			" cannot be used\n", dev->addr.domain, dev->addr.bus,
+			dev->addr.devid, dev->addr.function);
+	return -1;
+}
+
+/*
  * Detach device specified by its pci address.
  */
 int
-rte_eal_pci_detach(const struct rte_pci_addr *addr)
+rte_eal_pci_detach(const char *device_name)
 {
 	struct rte_pci_device *dev = NULL;
-	int ret = 0;
+	struct rte_pci_addr addr;
+	int ret = 1;
 
-	if (addr == NULL)
+	if (!device_name)
 		return -1;
 
+	memset(&addr, 0, sizeof(addr));
+	if (eal_parse_pci_DomBDF(device_name, &addr)) {
+		/* Device doesn't match PCI BDF naming format */
+		return 1;
+	}
+
 	FOREACH_DEVICE_ON_PCIBUS(dev) {
-		if (rte_eal_compare_pci_addr(&dev->addr, addr))
+		if (rte_eal_compare_pci_addr(&dev->addr, &addr))
 			continue;
 
 		ret = rte_eal_pci_detach_dev(dev);
@@ -391,8 +470,8 @@ rte_eal_pci_detach(const struct rte_pci_addr *addr)
 		free(dev);
 		return 0;
 	}
-	return -1;
 
+	return ret;
 err_return:
 	RTE_LOG(WARNING, EAL, "Requested device " PCI_PRI_FMT
 			" cannot be used\n", dev->addr.domain, dev->addr.bus,
diff --git a/lib/librte_eal/common/include/rte_bus.h b/lib/librte_eal/common/include/rte_bus.h
index 4b4bb36..1214908 100644
--- a/lib/librte_eal/common/include/rte_bus.h
+++ b/lib/librte_eal/common/include/rte_bus.h
@@ -59,6 +59,8 @@ TAILQ_HEAD(rte_bus_list, rte_bus);
 /* Bus list exposed */
 extern struct rte_bus_list rte_bus_list;
 
+#define FOREACH_BUS(bus_p)	TAILQ_FOREACH(bus_p, &rte_bus_list, next)
+
 /**
  * Bus specific scan for devices attached on the bus.
  * For each bus object, the scan would be reponsible for finding devices and
@@ -85,6 +87,33 @@ typedef int (*rte_bus_scan_t)(void);
 typedef int (*rte_bus_probe_t)(void);
 
 /**
+ * Attach a device to a bus, assuming it is 'connected' to the bus.
+ * A bus is responsible for scanning for devices. Attaching a new device is
+ * for reenabling the device after being detached/removed.
+ *
+ * @param device_name
+ *	Name of the device to attach.
+ *
+ * @return
+ *	0 for successful attach
+ *	!0 for unsuccessful attach (or incorrect device name)
+ */
+typedef int (*rte_bus_attach_t)(const char *device_name);
+
+/**
+ * Detach a named device from a bus. Implementation would check the existence
+ * of device on the bus and detach it.
+ *
+ * @param device_name
+ *	Name of the device to detach
+ *
+ * @return
+ *	0 for successful detaching
+ *	!0 if device not found or can't detach
+ */
+typedef int (*rte_bus_detach_t)(const char *device_name);
+
+/**
  * A structure describing a generic bus.
  */
 struct rte_bus {
@@ -92,6 +121,8 @@ 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_attach_t attach;     /**< Attach a named device */
+	rte_bus_detach_t detach;     /**< Detach a named device */
 };
 
 /**
diff --git a/lib/librte_eal/common/include/rte_pci.h b/lib/librte_eal/common/include/rte_pci.h
index 53793f3..820b9df 100644
--- a/lib/librte_eal/common/include/rte_pci.h
+++ b/lib/librte_eal/common/include/rte_pci.h
@@ -421,6 +421,36 @@ int
 rte_eal_pci_probe(void);
 
 /**
+ * Search and attach a PCI device to PCI Bus
+ * Implements rte_bus->attach
+ *
+ * @param device_name
+ *	Name of the device to search and attach
+ *
+ * @return
+ *	0 for successful removal of device
+ *	>0 if device not found on bus
+ *	<0 in case of error in removal.
+ */
+int
+rte_eal_pci_attach(const char *device_name);
+
+/**
+ * Search and detach a PCI device from PCI Bus
+ * Implements rte_bus->detach
+ *
+ * @param device_name
+ *	Name of the device to search and detach
+ *
+ * @return
+ *	0 for successful detaching of device
+ *	>0 if device not found on bus
+ *	<0 in case of error in removal.
+ */
+int
+rte_eal_pci_detach(const char *device_name);
+
+/**
  * Map the PCI device resources in user space virtual memory address
  *
  * Note that driver should not call this function when flag
@@ -494,21 +524,6 @@ void pci_unmap_resource(void *requested_addr, size_t size);
 int rte_eal_pci_probe_one(const struct rte_pci_addr *addr);
 
 /**
- * Close the single PCI device.
- *
- * Scan the content of the PCI bus, and find the pci device specified by pci
- * address, then call the remove() function for registered driver that has a
- * matching entry in its id_table for discovered device.
- *
- * @param addr
- *	The PCI Bus-Device-Function address to close.
- * @return
- *   - 0 on success.
- *   - Negative on error.
- */
-int rte_eal_pci_detach(const struct rte_pci_addr *addr);
-
-/**
  * Dump the content of the PCI bus.
  *
  * @param f
diff --git a/lib/librte_eal/linuxapp/eal/eal_pci.c b/lib/librte_eal/linuxapp/eal/eal_pci.c
index 51522af..4c562c5 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci.c
+++ b/lib/librte_eal/linuxapp/eal/eal_pci.c
@@ -720,6 +720,8 @@ struct rte_pci_bus rte_pci_bus = {
 	.bus = {
 		.scan = rte_eal_pci_scan,
 		.probe = rte_eal_pci_probe,
+		.attach = rte_eal_pci_attach,
+		.detach = rte_eal_pci_detach,
 	},
 	.device_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.device_list),
 	.driver_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.driver_list),
-- 
2.7.4