[PATCH 2/5] ethdev: add an iterator to match some devargs input

[Thomas Monjalon <thomas@monjalon.net>]

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
---
 lib/librte_eal/common/include/rte_common.h |  6 ++
 lib/librte_ethdev/ethdev_private.c         | 10 ++-
 lib/librte_ethdev/ethdev_private.h         |  6 ++
 lib/librte_ethdev/rte_ethdev.c             | 87 ++++++++++++++++++++++
 lib/librte_ethdev/rte_ethdev.h             | 56 ++++++++++++++
 lib/librte_ethdev/rte_ethdev_version.map   |  2 +
 6 files changed, 166 insertions(+), 1 deletion(-)

diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
index 069c13ec7..2269e5456 100644
--- a/lib/librte_eal/common/include/rte_common.h
+++ b/lib/librte_eal/common/include/rte_common.h
@@ -164,6 +164,12 @@ static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void)
  */
 #define RTE_PTR_DIFF(ptr1, ptr2) ((uintptr_t)(ptr1) - (uintptr_t)(ptr2))
 
+/**
+ * Workaround to cast a const field of a structure to non-const type.
+ */
+#define RTE_CAST_FIELD(var,field,type) \
+	(*(type*)((uintptr_t)(var) + offsetof(typeof(*(var)), field)))
+
 /*********** Macros/static functions for doing alignment ********/
 
 
diff --git a/lib/librte_ethdev/ethdev_private.c b/lib/librte_ethdev/ethdev_private.c
index 768c8b2ed..acc787dba 100644
--- a/lib/librte_ethdev/ethdev_private.c
+++ b/lib/librte_ethdev/ethdev_private.c
@@ -5,6 +5,14 @@
 #include "rte_ethdev.h"
 #include "ethdev_private.h"
 
+uint16_t
+eth_dev_to_id(const struct rte_eth_dev *dev)
+{
+	if (dev == NULL)
+		return RTE_MAX_ETHPORTS;
+	return dev - rte_eth_devices;
+}
+
 struct rte_eth_dev *
 eth_find_device(const struct rte_eth_dev *start, rte_eth_cmp_t cmp,
 		const void *data)
@@ -18,7 +26,7 @@ eth_find_device(const struct rte_eth_dev *start, rte_eth_cmp_t cmp,
 	     start > &rte_eth_devices[RTE_MAX_ETHPORTS]))
 		return NULL;
 	if (start != NULL)
-		idx = start - &rte_eth_devices[0] + 1;
+		idx = eth_dev_to_id(start) + 1;
 	else
 		idx = 0;
 	for (; idx < RTE_MAX_ETHPORTS; idx++) {
diff --git a/lib/librte_ethdev/ethdev_private.h b/lib/librte_ethdev/ethdev_private.h
index 0f5c6d5c4..e67cf6831 100644
--- a/lib/librte_ethdev/ethdev_private.h
+++ b/lib/librte_ethdev/ethdev_private.h
@@ -11,6 +11,12 @@
 extern "C" {
 #endif
 
+/*
+ * Convert rte_eth_dev pointer to port id.
+ * NULL will be translated to RTE_MAX_ETHPORTS.
+ */
+uint16_t eth_dev_to_id(const struct rte_eth_dev *dev);
+
 /* Generic rte_eth_dev comparison function. */
 typedef int (*rte_eth_cmp_t)(const struct rte_eth_dev *, const void *);
 
diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
index ef99f7068..83ab28c23 100644
--- a/lib/librte_ethdev/rte_ethdev.c
+++ b/lib/librte_ethdev/rte_ethdev.c
@@ -36,11 +36,13 @@
 #include <rte_spinlock.h>
 #include <rte_string_fns.h>
 #include <rte_kvargs.h>
+#include <rte_class.h>
 
 #include "rte_ether.h"
 #include "rte_ethdev.h"
 #include "rte_ethdev_driver.h"
 #include "ethdev_profile.h"
+#include "ethdev_private.h"
 
 int rte_eth_dev_logtype;
 
@@ -181,6 +183,91 @@ enum {
 	STAT_QMAP_RX
 };
 
+int __rte_experimental
+rte_eth_iterator_init(struct rte_dev_iterator *iter, const char *devargs_str)
+{
+#define iter_anybus_str "class=eth,"
+	int ret;
+	struct rte_devargs devargs;
+	const char *bus_param_key;
+	char *bus_str;
+	size_t bus_str_size;
+
+	memset(iter, 0, sizeof(*iter));
+
+	/*
+	 * The devargs string may use various syntaxes:
+	 *   - 0000:08:00.0,representor=[1-3]
+	 *   - pci:0000:06:00.0,representor=[0,5]
+	 * A new syntax is in development (not yet supported):
+	 *   - bus=X,paramX=x/class=Y,paramY=y/driver=Z,paramZ=z
+	 */
+
+	/* Split bus, device and parameters. */
+	ret = rte_devargs_parse(&devargs, devargs_str);
+	if (ret != 0)
+		return ret;
+
+	/* Assume parameters of old syntax can match only at ethdev level. */
+	iter->cls_str = devargs.args;
+
+	iter->bus = devargs.bus;
+	if (iter->bus->dev_iterate == NULL)
+		ret = -ENOTSUP; /* share error log with below */
+
+	/* Convert bus args to new syntax for use with new API dev_iterate. */
+	if (strcmp(iter->bus->name, "vdev") == 0)
+		bus_param_key = "name";
+	else if (strcmp(iter->bus->name, "pci") == 0)
+		bus_param_key = "addr";
+	else
+		ret = -ENOTSUP;
+	if (ret < 0) {
+		RTE_LOG(ERR, EAL, "Bus %s does not support iterating.\n",
+				iter->bus->name);
+		return -ENOTSUP;
+	}
+	bus_str_size = strlen(bus_param_key) + strlen(devargs.name) + 2;
+	bus_str = malloc(bus_str_size);
+	if (bus_str == NULL)
+		return -ENOMEM;
+	ret = snprintf(bus_str, bus_str_size, "%s=%s",
+			bus_param_key, devargs.name);
+	if (ret < 0) {
+		free(bus_str);
+		return -EINVAL;
+	}
+	iter->bus_str = bus_str;
+
+	iter->cls = rte_class_find_by_name("eth");
+	return 0;
+}
+
+uint16_t __rte_experimental
+rte_eth_iterator_next(struct rte_dev_iterator *iter)
+{
+	if (iter->cls == NULL) /* invalid ethdev iterator */
+		return RTE_MAX_ETHPORTS;
+
+	do { /* loop for matching rte_device */
+		if (iter->class_device == NULL) {
+			iter->device = iter->bus->dev_iterate(
+					iter->device, iter->bus_str, iter);
+			if (iter->device == NULL)
+				break;
+		}
+		iter->class_device = iter->cls->dev_iterate(
+				iter->class_device, iter->cls_str, iter);
+		if (iter->class_device != NULL)
+			return eth_dev_to_id(iter->class_device);
+	} while (iter->class_device == NULL);
+
+	/* No more ethdev port to iterate. */
+	free(RTE_CAST_FIELD(iter, bus_str, char *)); /* workaround const */
+	iter->bus_str = NULL;
+	return RTE_MAX_ETHPORTS;
+}
+
 uint16_t
 rte_eth_find_next(uint16_t port_id)
 {
diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
index 012577b0a..d5a457216 100644
--- a/lib/librte_ethdev/rte_ethdev.h
+++ b/lib/librte_ethdev/rte_ethdev.h
@@ -166,6 +166,62 @@ extern int rte_eth_dev_logtype;
 
 struct rte_mbuf;
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Initializes a device iterator.
+ *
+ * This iterator allows accessing a list of devices matching some devargs.
+ *
+ * @param iter
+ *   Device iterator handle initialized by the function.
+ *   The field bus_str is dynamically allocated and must be freed.
+ *
+ * @param devargs
+ *   Device description string.
+ *
+ * @return
+ *   0 on successful initialization, negative otherwise.
+ */
+__rte_experimental
+int rte_eth_iterator_init(struct rte_dev_iterator *iter, const char *devargs);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Iterates on devices with devargs filter.
+ * The ownership is not checked.
+ *
+ * The next port id is returned, and the iterator is updated.
+ *
+ * @param iter
+ *   Device iterator handle initialized by rte_eth_iterator_init().
+ *   The field bus_str is freed when no more port is found.
+ *
+ * @return
+ *   A port id if found, RTE_MAX_ETHPORTS otherwise.
+ */
+__rte_experimental
+uint16_t rte_eth_iterator_next(struct rte_dev_iterator *iter);
+
+/**
+ * Macro to iterate over all ethdev ports matching some devargs.
+ *
+ * @param id
+ *   Iterated port id of type uint16_t.
+ * @param devargs
+ *   Device parameters input as string of type char*.
+ * @param iter
+ *   Iterator handle of type struct rte_dev_iterator, used internally.
+ */
+#define RTE_ETH_FOREACH_MATCHING_DEV(id, devargs, iter) \
+	for (rte_eth_iterator_init(iter, devargs), \
+	     id = rte_eth_iterator_next(iter); \
+	     id != RTE_MAX_ETHPORTS; \
+	     id = rte_eth_iterator_next(iter))
+
 /**
  * A structure used to retrieve statistics for an Ethernet port.
  * Not all statistics fields in struct rte_eth_stats are supported
diff --git a/lib/librte_ethdev/rte_ethdev_version.map b/lib/librte_ethdev/rte_ethdev_version.map
index 38f117f01..e009988fd 100644
--- a/lib/librte_ethdev/rte_ethdev_version.map
+++ b/lib/librte_ethdev/rte_ethdev_version.map
@@ -237,6 +237,8 @@ EXPERIMENTAL {
 	rte_eth_dev_owner_unset;
 	rte_eth_dev_rx_offload_name;
 	rte_eth_dev_tx_offload_name;
+	rte_eth_iterator_init;
+	rte_eth_iterator_next;
 	rte_eth_switch_domain_alloc;
 	rte_eth_switch_domain_free;
 	rte_flow_expand_rss;
-- 
2.19.0