net/af_xdp: support power monitoring

Implement support for .get_monitor_addr in AF_XDP driver.

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>

doc/guides/nics/features/af_xdp.ini

@@ -5,6 +5,7 @@
 ;
 [Features]
 Link status          = Y
+Power mgmt address monitor = Y
 MTU update           = Y
 Promiscuous mode     = Y
 Stats per queue      = Y

drivers/net/af_xdp/rte_eth_af_xdp.c

@@ -37,6 +37,7 @@
 #include <rte_malloc.h>
 #include <rte_ring.h>
 #include <rte_spinlock.h>
+#include <rte_power_intrinsics.h>
 
 #include "compat.h"
 
@@ -788,6 +789,38 @@ eth_dev_configure(struct rte_eth_dev *dev)
 	return 0;
 }
 
+#define CLB_VAL_IDX 0
+static int
+eth_monitor_callback(const uint64_t value,
+		const uint64_t opaque[RTE_POWER_MONITOR_OPAQUE_SZ])
+{
+	const uint64_t v = opaque[CLB_VAL_IDX];
+	const uint64_t m = (uint32_t)~0;
+
+	/* if the value has changed, abort entering power optimized state */
+	return (value & m) == v ? 0 : -1;
+}
+
+static int
+eth_get_monitor_addr(void *rx_queue, struct rte_power_monitor_cond *pmc)
+{
+	struct pkt_rx_queue *rxq = rx_queue;
+	unsigned int *prod = rxq->rx.producer;
+	const uint32_t cur_val = rxq->rx.cached_prod; /* use cached value */
+
+	/* watch for changes in producer ring */
+	pmc->addr = (void *)prod;
+
+	/* store current value */
+	pmc->opaque[CLB_VAL_IDX] = cur_val;
+	pmc->fn = eth_monitor_callback;
+
+	/* AF_XDP producer ring index is 32-bit */
+	pmc->size = sizeof(uint32_t);
+
+	return 0;
+}
+
 static int
 eth_dev_info(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info)
 {
@@ -1448,6 +1481,7 @@ static const struct eth_dev_ops ops = {
 	.link_update = eth_link_update,
 	.stats_get = eth_stats_get,
 	.stats_reset = eth_stats_reset,
+	.get_monitor_addr = eth_get_monitor_addr,
 };
 
 /** parse busy_budget argument */