[dpdk-dev] [PATCH V9 5/5] pci: add driver auto bind for hot insertion

[Jeff Guo]

Normally we bind nic driver before application running, so if we want to
automatically driver binding after application run, need to implement
a auto bind function, that would benefit for hot insertion case, when detect
hot insertion uevent of device, auto bind the driver according some user
policy and then attach device, let app running smoothly and automatically
when hotplug behavior occur.

Signed-off-by: Jeff Guo <jia.guo at intel.com>
---
v9->v8:
split the patch set into small and explicit patch
---
 drivers/bus/pci/bsd/pci.c               |  7 +++++
 drivers/bus/pci/linux/pci.c             | 53 +++++++++++++++++++++++++++++++++
 drivers/bus/pci/pci_common.c            |  1 +
 drivers/bus/pci/rte_bus_pci.h           | 14 +++++++++
 drivers/bus/vdev/vdev.c                 |  9 ++++++
 lib/librte_eal/common/eal_common_bus.c  |  1 +
 lib/librte_eal/common/include/rte_bus.h | 18 +++++++++++
 lib/librte_eal/linuxapp/eal/eal_dev.c   |  7 +++++
 8 files changed, 110 insertions(+)

diff --git a/drivers/bus/pci/bsd/pci.c b/drivers/bus/pci/bsd/pci.c
index d7165b9..2d1d24f 100644
--- a/drivers/bus/pci/bsd/pci.c
+++ b/drivers/bus/pci/bsd/pci.c
@@ -672,3 +672,10 @@ rte_pci_ioport_unmap(struct rte_pci_ioport *p)
 
 	return ret;
 }
+
+int
+rte_pci_dev_bind_driver(const char *dev_name, const char *drv_type)
+{
+	return -1;
+}
+
diff --git a/drivers/bus/pci/linux/pci.c b/drivers/bus/pci/linux/pci.c
index 7aa3079..cec1489 100644
--- a/drivers/bus/pci/linux/pci.c
+++ b/drivers/bus/pci/linux/pci.c
@@ -859,3 +859,56 @@ rte_pci_ioport_unmap(struct rte_pci_ioport *p)
 
 	return ret;
 }
+
+int
+rte_pci_dev_bind_driver(const char *dev_name, const char *drv_type)
+{
+	char drv_bind_path[1024];
+	char drv_override_path[1024]; /* contains the /dev/uioX */
+	int drv_override_fd;
+	int drv_bind_fd;
+
+	RTE_SET_USED(drv_type);
+
+	snprintf(drv_override_path, sizeof(drv_override_path),
+		"/sys/bus/pci/devices/%s/driver_override", dev_name);
+
+	/* specify the driver for a device by writing to driver_override */
+	drv_override_fd = open(drv_override_path, O_WRONLY);
+	if (drv_override_fd < 0) {
+		RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
+			drv_override_path, strerror(errno));
+		goto err;
+	}
+
+	if (write(drv_override_fd, drv_type, sizeof(drv_type)) < 0) {
+		RTE_LOG(ERR, EAL,
+			"Error: bind failed - Cannot write "
+			"driver %s to device %s\n", drv_type, dev_name);
+		goto err;
+	}
+
+	close(drv_override_fd);
+
+	snprintf(drv_bind_path, sizeof(drv_bind_path),
+		"/sys/bus/pci/drivers/%s/bind", drv_type);
+
+	/* do the bind by writing device to the specific driver  */
+	drv_bind_fd = open(drv_bind_path, O_WRONLY | O_APPEND);
+	if (drv_bind_fd < 0) {
+		RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
+			drv_bind_path, strerror(errno));
+		goto err;
+	}
+
+	if (write(drv_bind_fd, dev_name, sizeof(dev_name)) < 0)
+		goto err;
+
+	close(drv_bind_fd);
+	return 0;
+err:
+	close(drv_override_fd);
+	close(drv_bind_fd);
+	return -1;
+}
+
diff --git a/drivers/bus/pci/pci_common.c b/drivers/bus/pci/pci_common.c
index 3fbe9d7..54601a9 100644
--- a/drivers/bus/pci/pci_common.c
+++ b/drivers/bus/pci/pci_common.c
@@ -574,6 +574,7 @@ struct rte_pci_bus rte_pci_bus = {
 		.parse = pci_parse,
 		.get_iommu_class = rte_pci_get_iommu_class,
 		.remap_device = pci_remap_device,
+		.bind_driver = rte_pci_dev_bind_driver,
 	},
 	.device_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.device_list),
 	.driver_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.driver_list),
diff --git a/drivers/bus/pci/rte_bus_pci.h b/drivers/bus/pci/rte_bus_pci.h
index 65337eb..1662f3b 100644
--- a/drivers/bus/pci/rte_bus_pci.h
+++ b/drivers/bus/pci/rte_bus_pci.h
@@ -344,6 +344,20 @@ void rte_pci_ioport_read(struct rte_pci_ioport *p,
 void rte_pci_ioport_write(struct rte_pci_ioport *p,
 		const void *data, size_t len, off_t offset);
 
+/**
+ * It can be used to bind a device to a specific type of driver.
+ *
+ * @param dev_name
+ *  The device name.
+ * @param drv_type
+ *  The specific driver's type.
+ *
+ * @return
+ *  - On success, zero.
+ *  - On failure, a negative value.
+ */
+int rte_pci_dev_bind_driver(const char *dev_name, const char *drv_type);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/drivers/bus/vdev/vdev.c b/drivers/bus/vdev/vdev.c
index c9cd369..773f6e0 100644
--- a/drivers/bus/vdev/vdev.c
+++ b/drivers/bus/vdev/vdev.c
@@ -349,6 +349,14 @@ vdev_remap_device(struct rte_device *dev)
 }
 
 static int
+vdev_bind_driver(const char *dev_name, const char *drv_type)
+{
+	RTE_SET_USED(dev_name);
+	RTE_SET_USED(drv_type);
+	return 0;
+}
+
+static int
 vdev_plug(struct rte_device *dev)
 {
 	return vdev_probe_all_drivers(RTE_DEV_TO_VDEV(dev));
@@ -369,6 +377,7 @@ static struct rte_bus rte_vdev_bus = {
 	.unplug = vdev_unplug,
 	.parse = vdev_parse,
 	.remap_device = vdev_remap_device,
+	.bind_driver = vdev_bind_driver,
 };
 
 RTE_REGISTER_BUS(vdev, rte_vdev_bus);
diff --git a/lib/librte_eal/common/eal_common_bus.c b/lib/librte_eal/common/eal_common_bus.c
index bdb0e54..b7219c9 100644
--- a/lib/librte_eal/common/eal_common_bus.c
+++ b/lib/librte_eal/common/eal_common_bus.c
@@ -55,6 +55,7 @@ rte_bus_register(struct rte_bus *bus)
 	/* Buses supporting driver plug also require unplug. */
 	RTE_VERIFY(!bus->plug || bus->unplug);
 	RTE_VERIFY(bus->remap_device);
+	RTE_VERIFY(bus->bind_driver);
 
 	TAILQ_INSERT_TAIL(&rte_bus_list, bus, next);
 	RTE_LOG(DEBUG, EAL, "Registered [%s] bus.\n", bus->name);
diff --git a/lib/librte_eal/common/include/rte_bus.h b/lib/librte_eal/common/include/rte_bus.h
index 78990bc..fb03a74 100644
--- a/lib/librte_eal/common/include/rte_bus.h
+++ b/lib/librte_eal/common/include/rte_bus.h
@@ -212,6 +212,23 @@ typedef int (*rte_bus_parse_t)(const char *name, void *addr);
 typedef int (*rte_bus_remap_device_t)(struct rte_device *dev);
 
 /**
+ * Implementation specific bind driver function which is responsible for bind
+ * a explicit type of driver with a devices on that bus.
+ *
+ * @param dev_name
+ *	device textual description.
+ *
+ * @param drv_type
+ *	driver type textual description.
+ *
+ * @return
+ *	0 on success.
+ *	!0 on error.
+ */
+typedef int (*rte_bus_bind_driver_t)(const char *dev_name,
+				const char *drv_type);
+
+/**
  * Bus scan policies
  */
 enum rte_bus_scan_mode {
@@ -256,6 +273,7 @@ struct rte_bus {
 	rte_bus_unplug_t unplug;     /**< Remove single device from driver */
 	rte_bus_parse_t parse;       /**< Parse a device name */
 	rte_bus_remap_device_t remap_device;       /**< remap a device */
+	rte_bus_bind_driver_t bind_driver; /**< bind a driver for bus device */
 	struct rte_bus_conf conf;    /**< Bus configuration */
 	rte_bus_get_iommu_class_t get_iommu_class; /**< Get iommu class */
 };
diff --git a/lib/librte_eal/linuxapp/eal/eal_dev.c b/lib/librte_eal/linuxapp/eal/eal_dev.c
index d68ef9b..35db461 100644
--- a/lib/librte_eal/linuxapp/eal/eal_dev.c
+++ b/lib/librte_eal/linuxapp/eal/eal_dev.c
@@ -207,6 +207,13 @@ dev_uev_process(struct epoll_event *events, int nfds)
 					  NULL));
 			} else if (uevent.type == RTE_DEV_EVENT_ADD) {
 				if (dev == NULL) {
+					/**
+					 * bind the driver to the device
+					 * before user's add processing
+					 */
+					bus->bind_driver(
+						uevent.devname,
+						"igb_uio");
 					return(_rte_dev_callback_process(NULL,
 					  RTE_DEV_EVENT_ADD,
 					  uevent.devname));
-- 
2.7.4