dmadev: add device iterator

Add a function and wrapper macro to iterate over all DMA devices.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Reviewed-by: Conor Walsh <conor.walsh@intel.com>
Reviewed-by: Kevin Laatz <kevin.laatz@intel.com>

lib/dmadev/rte_dmadev.c

@@ -49,6 +49,19 @@ rte_dma_dev_max(size_t dev_max)
 	return 0;
 }
 
+int16_t
+rte_dma_next_dev(int16_t start_dev_id)
+{
+	int16_t dev_id = start_dev_id;
+	while (dev_id < dma_devices_max && rte_dma_devices[dev_id].state == RTE_DMA_DEV_UNUSED)
+		dev_id++;
+
+	if (dev_id < dma_devices_max)
+		return dev_id;
+
+	return -1;
+}
+
 static int
 dma_check_name(const char *name)
 {

lib/dmadev/rte_dmadev.h

@@ -220,6 +220,24 @@ bool rte_dma_is_valid(int16_t dev_id);
 __rte_experimental
 uint16_t rte_dma_count_avail(void);
 
+/**
+ * Iterates over valid dmadev instances.
+ *
+ * @param start_dev_id
+ *   The id of the next possible dmadev.
+ * @return
+ *   Next valid dmadev, UINT16_MAX if there is none.
+ */
+__rte_experimental
+int16_t rte_dma_next_dev(int16_t start_dev_id);
+
+/** Utility macro to iterate over all available dmadevs */
+#define RTE_DMA_FOREACH_DEV(p) \
+	for (p = rte_dma_next_dev(0); \
+	     p != -1; \
+	     p = rte_dma_next_dev(p + 1))
+
+
 /**@{@name DMA capability
  * @see struct rte_dma_info::dev_capa
  */

lib/dmadev/version.map

@@ -15,6 +15,7 @@ EXPERIMENTAL {
 	rte_dma_get_dev_id_by_name;
 	rte_dma_info_get;
 	rte_dma_is_valid;
+	rte_dma_next_dev;
 	rte_dma_start;
 	rte_dma_stats_get;
 	rte_dma_stats_reset;