[PATCH v2 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 | 35 +++++++++++++++++++++++++++++++++++
 lib/librte_ether/rte_ethdev.h | 28 ++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
index 27b52131ef01..4897e1dcda14 100644
--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -1495,6 +1495,41 @@ rte_eth_link_get_nowait(uint16_t port_id, struct rte_eth_link *eth_link)
 	}
 }
 
+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;
+}
+
+void
+_rte_eth_linkstatus_get(const struct rte_eth_dev *dev,
+			struct rte_eth_link *link)
+{
+	const uint64_t *src = (const uint64_t *)&(dev->data->dev_link);
+	volatile uint64_t *dst = (uint64_t *)link;
+
+	RTE_BUILD_BUG_ON(sizeof(*link) != sizeof(uint64_t));
+
+	/*
+	 * Note: this should never fail since both destination and expected
+	 * values are the same and are a pointer from caller.
+	 */
+	rte_atomic64_cmpset(dst, *dst, *src);
+}
+
 int
 rte_eth_stats_get(uint16_t port_id, struct rte_eth_stats *stats)
 {
diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
index b10e2a92da71..b47402b797c3 100644
--- a/lib/librte_ether/rte_ethdev.h
+++ b/lib/librte_ether/rte_ethdev.h
@@ -2218,6 +2218,34 @@ int rte_eth_dev_set_link_down(uint16_t port_id);
  */
 void rte_eth_dev_close(uint16_t port_id);
 
+
+/**
+ * @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
+ *  -1 if link state has changed, 0 if the same.
+ */
+int _rte_eth_linkstatus_set(struct rte_eth_dev *dev,
+			    const struct rte_eth_link *link);
+
+/**
+ * @internal
+ * Atomically get the link speed and status.
+ * @param dev
+ *  Pointer to struct rte_eth_dev.
+ * @param link
+ *  link status value.
+ */
+void _rte_eth_linkstatus_get(const struct rte_eth_dev *dev,
+			     struct rte_eth_link *link);
+
 /**
  * Reset a Ethernet device and keep its port id.
  *
-- 
2.15.1