[PATCH v8 02/15] ethdev: add linkstatus get/set helper functions

[Stephen Hemminger <stephen@networkplumber.org>]

Many drivers are all doing copy/paste of the same code to atomically
update the link status. Reduce duplication, and allow for future
changes by having common function for this.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 lib/librte_ether/rte_ethdev.c        | 22 +++----------
 lib/librte_ether/rte_ethdev_driver.h | 63 ++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 18 deletions(-)

diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
index f285ba278967..344397101abd 100644
--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -1578,20 +1578,6 @@ rte_eth_allmulticast_get(uint16_t port_id)
 	return dev->data->all_multicast;
 }
 
-static inline int
-rte_eth_dev_atomic_read_link_status(struct rte_eth_dev *dev,
-				struct rte_eth_link *link)
-{
-	struct rte_eth_link *dst = link;
-	struct rte_eth_link *src = &(dev->data->dev_link);
-
-	if (rte_atomic64_cmpset((uint64_t *)dst, *(uint64_t *)dst,
-					*(uint64_t *)src) == 0)
-		return -1;
-
-	return 0;
-}
-
 void
 rte_eth_link_get(uint16_t port_id, struct rte_eth_link *eth_link)
 {
@@ -1600,8 +1586,8 @@ rte_eth_link_get(uint16_t port_id, struct rte_eth_link *eth_link)
 	RTE_ETH_VALID_PORTID_OR_RET(port_id);
 	dev = &rte_eth_devices[port_id];
 
-	if (dev->data->dev_conf.intr_conf.lsc != 0)
-		rte_eth_dev_atomic_read_link_status(dev, eth_link);
+	if (dev->data->dev_conf.intr_conf.lsc)
+		rte_eth_linkstatus_get(dev, eth_link);
 	else {
 		RTE_FUNC_PTR_OR_RET(*dev->dev_ops->link_update);
 		(*dev->dev_ops->link_update)(dev, 1);
@@ -1617,8 +1603,8 @@ rte_eth_link_get_nowait(uint16_t port_id, struct rte_eth_link *eth_link)
 	RTE_ETH_VALID_PORTID_OR_RET(port_id);
 	dev = &rte_eth_devices[port_id];
 
-	if (dev->data->dev_conf.intr_conf.lsc != 0)
-		rte_eth_dev_atomic_read_link_status(dev, eth_link);
+	if (dev->data->dev_conf.intr_conf.lsc)
+		rte_eth_linkstatus_get(dev, eth_link);
 	else {
 		RTE_FUNC_PTR_OR_RET(*dev->dev_ops->link_update);
 		(*dev->dev_ops->link_update)(dev, 0);
diff --git a/lib/librte_ether/rte_ethdev_driver.h b/lib/librte_ether/rte_ethdev_driver.h
index 45f08c65ec1e..fd3e1c0bd21f 100644
--- a/lib/librte_ether/rte_ethdev_driver.h
+++ b/lib/librte_ether/rte_ethdev_driver.h
@@ -68,6 +68,69 @@ struct rte_eth_dev *rte_eth_dev_attach_secondary(const char *name);
  */
 int rte_eth_dev_release_port(struct rte_eth_dev *eth_dev);
 
+/**
+ * @internal
+ * Atomically set the link status for the specific device.
+ * It is for use by DPDK device driver use only.
+ * User applications should not call it
+ *
+ * @param dev
+ *  Pointer to struct rte_eth_dev.
+ * @param link
+ *  New link status value.
+ * @return
+ *  Same convention as eth_link_update operation.
+ *  0   if link up status has changed
+ *  -1  if link up status was unchanged
+ */
+static inline int
+rte_eth_linkstatus_set(struct rte_eth_dev *dev,
+		       const struct rte_eth_link *new_link)
+{
+	volatile uint64_t *dev_link
+		 = (volatile uint64_t *)&(dev->data->dev_link);
+	union {
+		uint64_t val64;
+		struct rte_eth_link link;
+	} orig;
+
+	RTE_BUILD_BUG_ON(sizeof(*new_link) != sizeof(uint64_t));
+
+	orig.val64 = rte_atomic64_exchange(dev_link,
+					   *(const uint64_t *)new_link);
+
+	return (orig.link.link_status == new_link->link_status) ? -1 : 0;
+}
+
+/**
+ * @internal
+ * Atomically get the link speed and status.
+ *
+ * @param dev
+ *  Pointer to struct rte_eth_dev.
+ * @param link
+ *  link status value.
+ */
+static inline void
+rte_eth_linkstatus_get(const struct rte_eth_dev *dev,
+		       struct rte_eth_link *link)
+{
+	volatile uint64_t *src = (uint64_t *)&(dev->data->dev_link);
+	uint64_t *dst = (uint64_t *)link;
+
+	RTE_BUILD_BUG_ON(sizeof(*link) != sizeof(uint64_t));
+
+#ifdef __LP64__
+	/* if cpu arch has 64 bit unsigned lon then implicitly atomic */
+	*dst = *src;
+#else
+	/* can't use rte_atomic64_read because it returns signed int */
+	do {
+		*dst = *src;
+	} while (!rte_atomic64_cmpset(src, *dst, *dst));
+#endif
+}
+
 /**
  * @internal
  * Release device queues and clear its configuration to force the user
-- 
2.15.1