[dpdk-dev] [PATCH v6 5/8] eal: introduce bus scan and probe in EAL

[Shreyansh Jain]

Each bus implementation defines their own callbacks for scanning bus
and probing devices available on the bus. Enable EAL to call bus specific
scan and probe functions during DPDK initialization.

Existing PCI scan/probe continues to exist. It will removed in subsequent
patches.

Signed-off-by: Shreyansh Jain <shreyansh.jain at nxp.com>
---
 lib/librte_eal/bsdapp/eal/eal.c                 |  8 +++
 lib/librte_eal/bsdapp/eal/eal_pci.c             | 11 ++++
 lib/librte_eal/bsdapp/eal/rte_eal_version.map   |  2 +
 lib/librte_eal/common/eal_common_bus.c          | 41 +++++++++++++++
 lib/librte_eal/common/eal_common_pci.c          | 33 ++++++++++++
 lib/librte_eal/common/include/rte_bus.h         | 39 ++++++++++++++
 lib/librte_eal/common/include/rte_pci.h         | 68 +++++++++++++++++++++++++
 lib/librte_eal/linuxapp/eal/eal.c               |  8 +++
 lib/librte_eal/linuxapp/eal/eal_pci.c           | 15 ++++++
 lib/librte_eal/linuxapp/eal/rte_eal_version.map |  2 +
 10 files changed, 227 insertions(+)

diff --git a/lib/librte_eal/bsdapp/eal/eal.c b/lib/librte_eal/bsdapp/eal/eal.c
index 2206277..a584447 100644
--- a/lib/librte_eal/bsdapp/eal/eal.c
+++ b/lib/librte_eal/bsdapp/eal/eal.c
@@ -64,6 +64,7 @@
 #include <rte_string_fns.h>
 #include <rte_cpuflags.h>
 #include <rte_interrupts.h>
+#include <rte_bus.h>
 #include <rte_pci.h>
 #include <rte_dev.h>
 #include <rte_devargs.h>
@@ -577,6 +578,9 @@ rte_eal_init(int argc, char **argv)
 		rte_config.master_lcore, thread_id, cpuset,
 		ret == 0 ? "" : "...");
 
+	if (rte_bus_scan())
+		rte_panic("Cannot scan the buses for devices\n");
+
 	RTE_LCORE_FOREACH_SLAVE(i) {
 
 		/*
@@ -613,6 +617,10 @@ rte_eal_init(int argc, char **argv)
 	if (rte_eal_pci_probe())
 		rte_panic("Cannot probe PCI\n");
 
+	/* Probe all the buses and devices/drivers on them */
+	if (rte_bus_probe())
+		rte_panic("Cannot probe devices\n");
+
 	if (rte_eal_dev_init() < 0)
 		rte_panic("Cannot init pmd devices\n");
 
diff --git a/lib/librte_eal/bsdapp/eal/eal_pci.c b/lib/librte_eal/bsdapp/eal/eal_pci.c
index 3a5c315..48bfe24 100644
--- a/lib/librte_eal/bsdapp/eal/eal_pci.c
+++ b/lib/librte_eal/bsdapp/eal/eal_pci.c
@@ -673,3 +673,14 @@ rte_eal_pci_init(void)
 	}
 	return 0;
 }
+
+struct rte_pci_bus rte_pci_bus = {
+	.bus = {
+		.scan = rte_eal_pci_scan,
+		.probe = rte_eal_pci_probe,
+	},
+	.device_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.device_list),
+	.driver_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.driver_list),
+};
+
+RTE_REGISTER_BUS(PCI_BUS_NAME, rte_pci_bus.bus);
diff --git a/lib/librte_eal/bsdapp/eal/rte_eal_version.map b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
index c015889..c43140c 100644
--- a/lib/librte_eal/bsdapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
@@ -182,6 +182,8 @@ DPDK_17.02 {
 	rte_bus_dump;
 	rte_bus_register;
 	rte_bus_unregister;
+	rte_bus_probe;
+	rte_bus_scan;
 	rte_pci_match;
 
 } DPDK_16.11;
diff --git a/lib/librte_eal/common/eal_common_bus.c b/lib/librte_eal/common/eal_common_bus.c
index 35baff8..9c91ca6 100644
--- a/lib/librte_eal/common/eal_common_bus.c
+++ b/lib/librte_eal/common/eal_common_bus.c
@@ -53,6 +53,7 @@ rte_bus_register(struct rte_bus *bus)
 	RTE_VERIFY(bus->name && strlen(bus->name));
 	/* A bus should mandatorily have the scan implemented */
 	RTE_VERIFY(bus->scan);
+	RTE_VERIFY(bus->probe);
 
 	TAILQ_INSERT_TAIL(&rte_bus_list, bus, next);
 	RTE_LOG(INFO, EAL, "Registered [%s] bus.\n", bus->name);
@@ -66,6 +67,46 @@ rte_bus_unregister(struct rte_bus *bus)
 	RTE_LOG(INFO, EAL, "Unregistered [%s] bus.\n", bus->name);
 }
 
+/* Scan all the buses for registering devices */
+int
+rte_bus_scan(void)
+{
+	int ret;
+	struct rte_bus *bus = NULL;
+
+	TAILQ_FOREACH(bus, &rte_bus_list, next) {
+		ret = bus->scan();
+		if (ret) {
+			RTE_LOG(ERR, EAL, "Scan for (%s) bus failed.\n",
+				bus->name);
+			/* Error in scanning any bus stops the EAL init. */
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+/* Call bus specific probe */
+int
+rte_bus_probe(void)
+{
+	int ret;
+	struct rte_bus *bus;
+
+	/* For each bus registered with EAL */
+	TAILQ_FOREACH(bus, &rte_bus_list, next) {
+		ret = bus->probe();
+		if (ret) {
+			RTE_LOG(ERR, EAL, "Bus (%s) probe failed.\n",
+				bus->name);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
 /* dump one bus info */
 static int
 bus_dump_one(FILE *f, struct rte_bus *bus)
diff --git a/lib/librte_eal/common/eal_common_pci.c b/lib/librte_eal/common/eal_common_pci.c
index 0d799be..35da451 100644
--- a/lib/librte_eal/common/eal_common_pci.c
+++ b/lib/librte_eal/common/eal_common_pci.c
@@ -71,6 +71,7 @@
 
 #include <rte_interrupts.h>
 #include <rte_log.h>
+#include <rte_bus.h>
 #include <rte_pci.h>
 #include <rte_per_lcore.h>
 #include <rte_memory.h>
@@ -508,3 +509,35 @@ rte_eal_pci_unregister(struct rte_pci_driver *driver)
 	rte_eal_driver_unregister(&driver->driver);
 	TAILQ_REMOVE(&pci_driver_list, driver, next);
 }
+
+/* Add a PCI device to PCI Bus */
+void
+rte_eal_pci_add_device(struct rte_pci_bus *pci_bus,
+		       struct rte_pci_device *pci_dev)
+{
+	TAILQ_INSERT_TAIL(&pci_bus->device_list, pci_dev, next);
+	/* Update Bus references */
+	pci_dev->device.bus = &pci_bus->bus;
+}
+
+/* Insert a PCI device into a predefined position in PCI bus */
+void
+rte_eal_pci_insert_device(struct rte_pci_device *exist_pci_dev,
+			  struct rte_pci_device *new_pci_dev)
+{
+	TAILQ_INSERT_BEFORE(exist_pci_dev, new_pci_dev, next);
+	/* Update Bus references */
+	new_pci_dev->device.bus = exist_pci_dev->device.bus;
+}
+
+/* Remove a PCI device from PCI bus */
+void
+rte_eal_pci_remove_device(struct rte_pci_device *pci_dev)
+{
+	struct rte_pci_bus *pci_bus;
+
+	pci_bus = container_of(pci_dev->device.bus, struct rte_pci_bus, bus);
+	TAILQ_REMOVE(&pci_bus->device_list, pci_dev, next);
+	/* Update Bus references */
+	pci_dev->device.bus = NULL;
+}
diff --git a/lib/librte_eal/common/include/rte_bus.h b/lib/librte_eal/common/include/rte_bus.h
index 152451c..f1d4c2c 100644
--- a/lib/librte_eal/common/include/rte_bus.h
+++ b/lib/librte_eal/common/include/rte_bus.h
@@ -77,12 +77,30 @@ extern struct rte_bus_list rte_bus_list;
 typedef int (*rte_bus_scan_t)(void);
 
 /**
+ * Implementation specific probe function which is responsible for linking
+ * devices on that bus with applicable drivers.
+ *
+ * This is called while iterating over each registered bus. Bus object is
+ * passed along assuming this is wrapped around (embedded) by Implementation
+ * specific bus object.
+ *
+ * @param bus
+ *	Generic bus object which was registered with EAL
+ *
+ * @return
+ *	0 for successful probe
+ *	!0 for any error while probing
+ */
+typedef int (*rte_bus_probe_t)(void);
+
+/**
  * A structure describing a generic bus.
  */
 struct rte_bus {
 	TAILQ_ENTRY(rte_bus) next;   /**< Next bus object in linked list */
 	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 */
 };
 
 /**
@@ -104,6 +122,27 @@ void rte_bus_register(struct rte_bus *bus);
 void rte_bus_unregister(struct rte_bus *bus);
 
 /**
+ * Scan all the buses attached to the framework.
+ *
+ * @param void
+ * @return
+ *	0 in case of success in scanning all buses
+ *	!0 in case of failure to scan
+ */
+int rte_bus_scan(void);
+
+/**
+ * For each device on the bus, perform a driver 'match' and call the
+ * bus's probe for device initialization.
+ *
+ * @param void
+ * @return
+ *	0 for successful match/probe
+ *	!0 otherwise
+ */
+int rte_bus_probe(void);
+
+/**
  * Dump information of all the buses registered with EAL.
  *
  * @param f
diff --git a/lib/librte_eal/common/include/rte_pci.h b/lib/librte_eal/common/include/rte_pci.h
index 6c9ec39..a52b390 100644
--- a/lib/librte_eal/common/include/rte_pci.h
+++ b/lib/librte_eal/common/include/rte_pci.h
@@ -85,6 +85,7 @@ extern "C" {
 #include <rte_debug.h>
 #include <rte_interrupts.h>
 #include <rte_dev.h>
+#include <rte_bus.h>
 
 TAILQ_HEAD(pci_device_list, rte_pci_device); /**< PCI devices in D-linked Q. */
 TAILQ_HEAD(pci_driver_list, rte_pci_driver); /**< PCI drivers in D-linked Q. */
@@ -111,6 +112,25 @@ const char *pci_get_sysfs_path(void);
 /** Maximum number of PCI resources. */
 #define PCI_MAX_RESOURCE 6
 
+/** Name of PCI Bus */
+#define PCI_BUS_NAME "PCI"
+
+/* Forward declarations */
+struct rte_pci_device;
+struct rte_pci_driver;
+
+/** List of PCI devices */
+TAILQ_HEAD(rte_pci_device_list, rte_pci_device);
+/** List of PCI drivers */
+TAILQ_HEAD(rte_pci_driver_list, rte_pci_driver);
+
+/* PCI Bus iterators */
+#define FOREACH_DEVICE_ON_PCIBUS(p)	\
+		TAILQ_FOREACH(p, &(rte_pci_bus.device_list), next)
+
+#define FOREACH_DRIVER_ON_PCIBUS(p)	\
+		TAILQ_FOREACH(p, &(rte_pci_bus.driver_list), next)
+
 /**
  * A structure describing an ID for a PCI driver. Each driver provides a
  * table of these IDs for each device that it supports.
@@ -206,12 +226,22 @@ typedef int (pci_remove_t)(struct rte_pci_device *);
 struct rte_pci_driver {
 	TAILQ_ENTRY(rte_pci_driver) next;       /**< Next in list. */
 	struct rte_driver driver;               /**< Inherit core driver. */
+	struct rte_pci_bus *pci_bus;            /**< PCI bus reference */
 	pci_probe_t *probe;                     /**< Device Probe function. */
 	pci_remove_t *remove;                   /**< Device Remove function. */
 	const struct rte_pci_id *id_table;	/**< ID table, NULL terminated. */
 	uint32_t drv_flags;                     /**< Flags contolling handling of device. */
 };
 
+/**
+ * Structure describing the PCI bus
+ */
+struct rte_pci_bus {
+	struct rte_bus bus;               /**< Inherit the generic class */
+	struct rte_pci_device_list device_list;  /**< List of PCI devices */
+	struct rte_pci_driver_list driver_list;  /**< List of PCI drivers */
+};
+
 /** Device needs PCI BAR mapping (done with either IGB_UIO or VFIO) */
 #define RTE_PCI_DRV_NEED_MAPPING 0x0001
 /** Device driver supports link state interrupt */
@@ -523,6 +553,44 @@ RTE_PMD_EXPORT_NAME(nm, __COUNTER__)
 void rte_eal_pci_unregister(struct rte_pci_driver *driver);
 
 /**
+ * Add a PCI device to the PCI Bus (append to PCI Device list). This function
+ * also updates the bus references of the PCI Device (and the generic device
+ * object embedded within.
+ *
+ * @param pci_bus
+ *	PCI Bus reference to which device is to be added
+ * @param pci_dev
+ *	PCI device to add
+ * @return void
+ */
+void rte_eal_pci_add_device(struct rte_pci_bus *pci_bus,
+			    struct rte_pci_device *pci_dev);
+
+/**
+ * Insert a PCI device in the PCI Bus at a particular location in the device
+ * list. It also updates the PCI Bus reference of the new devices to be
+ * inserted.
+ *
+ * @param exist_pci_dev
+ *	Existing PCI device in PCI Bus
+ * @param pci_dev
+ *	PCI device to be added before exist_pci_dev
+ * @return void
+ */
+void rte_eal_pci_insert_device(struct rte_pci_device *exist_pci_dev,
+			       struct rte_pci_device *new_pci_dev);
+
+/**
+ * Remove a PCI device from the PCI Bus. This sets to NULL the bus references
+ * in the PCI device object as well as the generic device object.
+ *
+ * @param pci_dev
+ *	PCI device to be removed from PCI Bus
+ * @return void
+ */
+void rte_eal_pci_remove_device(struct rte_pci_device *pci_device);
+
+/**
  * Read PCI config space.
  *
  * @param device
diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
index 16dd5b9..f77ff5c 100644
--- a/lib/librte_eal/linuxapp/eal/eal.c
+++ b/lib/librte_eal/linuxapp/eal/eal.c
@@ -69,6 +69,7 @@
 #include <rte_string_fns.h>
 #include <rte_cpuflags.h>
 #include <rte_interrupts.h>
+#include <rte_bus.h>
 #include <rte_pci.h>
 #include <rte_dev.h>
 #include <rte_devargs.h>
@@ -844,6 +845,9 @@ rte_eal_init(int argc, char **argv)
 	if (rte_eal_intr_init() < 0)
 		rte_panic("Cannot init interrupt-handling thread\n");
 
+	if (rte_bus_scan())
+		rte_panic("Cannot scan the buses for devices\n");
+
 	RTE_LCORE_FOREACH_SLAVE(i) {
 
 		/*
@@ -884,6 +888,10 @@ rte_eal_init(int argc, char **argv)
 	if (rte_eal_pci_probe())
 		rte_panic("Cannot probe PCI\n");
 
+	/* Probe all the buses and devices/drivers on them */
+	if (rte_bus_probe())
+		rte_panic("Cannot probe devices\n");
+
 	if (rte_eal_dev_init() < 0)
 		rte_panic("Cannot init pmd devices\n");
 
diff --git a/lib/librte_eal/linuxapp/eal/eal_pci.c b/lib/librte_eal/linuxapp/eal/eal_pci.c
index e2fc219..300064d 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci.c
+++ b/lib/librte_eal/linuxapp/eal/eal_pci.c
@@ -35,6 +35,7 @@
 #include <dirent.h>
 
 #include <rte_log.h>
+#include <rte_bus.h>
 #include <rte_pci.h>
 #include <rte_eal_memconfig.h>
 #include <rte_malloc.h>
@@ -54,6 +55,9 @@
  * IGB_UIO driver (or doesn't initialize, if the device wasn't bound to it).
  */
 
+/* Forward declaration of PCI bus */
+struct rte_pci_bus rte_pci_bus;
+
 static int
 pci_get_kernel_driver_by_path(const char *filename, char *dri_name)
 {
@@ -723,3 +727,14 @@ rte_eal_pci_init(void)
 
 	return 0;
 }
+
+struct rte_pci_bus rte_pci_bus = {
+	.bus = {
+		.scan = rte_eal_pci_scan,
+		.probe = rte_eal_pci_probe,
+	},
+	.device_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.device_list),
+	.driver_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.driver_list),
+};
+
+RTE_REGISTER_BUS(PCI_BUS_NAME, rte_pci_bus.bus);
diff --git a/lib/librte_eal/linuxapp/eal/rte_eal_version.map b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
index 5ed2589..6f047c5 100644
--- a/lib/librte_eal/linuxapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
@@ -186,6 +186,8 @@ DPDK_17.02 {
 	rte_bus_dump;
 	rte_bus_register;
 	rte_bus_unregister;
+	rte_bus_probe;
+	rte_bus_scan;
 	rte_pci_match;
 
 } DPDK_16.11;
-- 
2.7.4