[v4] dmadev: add telemetry support

diff --git a/doc/guides/prog_guide/dmadev.rst b/doc/guides/prog_guide/dmadev.rst
index 77863f8028..2aa26d33b8 100644
--- a/doc/guides/prog_guide/dmadev.rst
+++ b/doc/guides/prog_guide/dmadev.rst
@@ -118,3 +118,27 @@  i.e. ``rte_dma_stats_get()``. The statistics returned for each device instance a
 * ``submitted``: The number of operations submitted to the device.
 * ``completed``: The number of operations which have completed (successful and failed).
 * ``errors``: The number of operations that completed with error.
+
+The dmadev library has support for displaying DMA device information
+through the Telemetry interface. Telemetry commands that can be used
+are shown below.
+
+#. Get the list of available DMA devices by ID::
+
+     --> /dmadev/list
+     {"/dmadev/list": [0, 1]}
+
+#. Get general information from a DMA device by passing the device id as a parameter::
+
+     --> /dmadev/info,0
+     {"/dmadev/info": {"name": "0000:00:01.0", "nb_vchans": 1, "numa_node": 0, "max_vchans": 1, "max_desc": 4096,
+     "min_desc": 32, "max_sges": 0, "capabilities": {"mem2mem": 1, "mem2dev": 0, "dev2mem": 0, ...}}}
+
+#. Get the statistics for a particular DMA device and virtual DMA channel by passing the device id and vchan id as parameters
+   (if a DMA device only has one virtual DMA channel you only need to pass the device id)::
+
+     --> /dmadev/stats,0,0
+     {"/dmadev/stats": {"submitted": 0, "completed": 0, "errors": 0}}
+
+For more information on how to use the Telemetry interface, see
+the :doc:`../howto/telemetry`.
diff --git a/doc/guides/rel_notes/release_22_07.rst b/doc/guides/rel_notes/release_22_07.rst
index 42a5f2d990..d6c434ae7b 100644
--- a/doc/guides/rel_notes/release_22_07.rst
+++ b/doc/guides/rel_notes/release_22_07.rst
@@ -55,6 +55,11 @@  New Features
      Also, make sure to start the actual text at the margin.
      =======================================================
 
+* **Added telemetry callbacks to dmadev library.**
+
+  Added telemetry callback functions which allow for a list of DMA devices,
+  stats for a DMA device, and other DMA device information to be queried.
+
 
 Removed Items
 -------------
diff --git a/lib/dmadev/meson.build b/lib/dmadev/meson.build
index d2fc85e8c7..2f17587b75 100644
--- a/lib/dmadev/meson.build
+++ b/lib/dmadev/meson.build
@@ -5,3 +5,5 @@  sources = files('rte_dmadev.c')
 headers = files('rte_dmadev.h')
 indirect_headers += files('rte_dmadev_core.h')
 driver_sdk_headers += files('rte_dmadev_pmd.h')
+
+deps += ['telemetry']
diff --git a/lib/dmadev/rte_dmadev.c b/lib/dmadev/rte_dmadev.c
index d4b32b2971..efdad52545 100644
--- a/lib/dmadev/rte_dmadev.c
+++ b/lib/dmadev/rte_dmadev.c
@@ -11,6 +11,7 @@ 
 #include <rte_malloc.h>
 #include <rte_memzone.h>
 #include <rte_string_fns.h>
+#include <rte_telemetry.h>
 
 #include "rte_dmadev.h"
 #include "rte_dmadev_pmd.h"
@@ -27,6 +28,22 @@  static struct {
 	struct rte_dma_dev_data data[0];
 } *dma_devices_shared_data;
 
+static const struct {
+	uint64_t capability;
+	const char *name;
+} capa_names[] = {
+	{ RTE_DMA_CAPA_MEM_TO_MEM,  "mem2mem" },
+	{ RTE_DMA_CAPA_MEM_TO_DEV,  "mem2dev" },
+	{ RTE_DMA_CAPA_DEV_TO_MEM,  "dev2mem" },
+	{ RTE_DMA_CAPA_DEV_TO_DEV,  "dev2dev" },
+	{ RTE_DMA_CAPA_SVA,         "sva"     },
+	{ RTE_DMA_CAPA_SILENT,      "silent"  },
+	{ RTE_DMA_CAPA_HANDLES_ERRORS, "handles_errors" },
+	{ RTE_DMA_CAPA_OPS_COPY,    "copy"    },
+	{ RTE_DMA_CAPA_OPS_COPY_SG, "copy_sg" },
+	{ RTE_DMA_CAPA_OPS_FILL,    "fill"    },
+};
+
 RTE_LOG_REGISTER_DEFAULT(rte_dma_logtype, INFO);
 #define RTE_DMA_LOG(level, ...) \
 	rte_log(RTE_LOG_ ## level, rte_dma_logtype, RTE_FMT("dma: " \
@@ -712,22 +729,6 @@  rte_dma_vchan_status(int16_t dev_id, uint16_t vchan, enum rte_dma_vchan_status *
 static const char *
 dma_capability_name(uint64_t capability)
 {
-	static const struct {
-		uint64_t capability;
-		const char *name;
-	} capa_names[] = {
-		{ RTE_DMA_CAPA_MEM_TO_MEM,  "mem2mem" },
-		{ RTE_DMA_CAPA_MEM_TO_DEV,  "mem2dev" },
-		{ RTE_DMA_CAPA_DEV_TO_MEM,  "dev2mem" },
-		{ RTE_DMA_CAPA_DEV_TO_DEV,  "dev2dev" },
-		{ RTE_DMA_CAPA_SVA,         "sva"     },
-		{ RTE_DMA_CAPA_SILENT,      "silent"  },
-		{ RTE_DMA_CAPA_HANDLES_ERRORS, "handles_errors" },
-		{ RTE_DMA_CAPA_OPS_COPY,    "copy"    },
-		{ RTE_DMA_CAPA_OPS_COPY_SG, "copy_sg" },
-		{ RTE_DMA_CAPA_OPS_FILL,    "fill"    },
-	};
-
 	const char *name = "unknown";
 	uint32_t i;
 
@@ -864,3 +865,132 @@  dma_fp_object_dummy(struct rte_dma_fp_object *obj)
 	obj->completed_status = dummy_completed_status;
 	obj->burst_capacity   = dummy_burst_capacity;
 }
+
+static int
+dmadev_handle_dev_list(const char *cmd __rte_unused,
+		const char *params __rte_unused,
+		struct rte_tel_data *d)
+{
+	int dev_id;
+
+	rte_tel_data_start_array(d, RTE_TEL_INT_VAL);
+	for (dev_id = 0; dev_id < dma_devices_max; dev_id++)
+		if (rte_dma_is_valid(dev_id))
+			rte_tel_data_add_array_int(d, dev_id);
+
+	return 0;
+}
+
+#define ADD_CAPA(td, dc, c) rte_tel_data_add_dict_int(td, dma_capability_name(c), !!(dc & c))
+
+static int
+dmadev_handle_dev_info(const char *cmd __rte_unused,
+		const char *params, struct rte_tel_data *d)
+{
+	struct rte_dma_info dma_info;
+	struct rte_tel_data *dma_caps;
+	int dev_id, ret;
+	uint64_t dev_capa;
+	char *end_param;
+
+	if (params == NULL || strlen(params) == 0 || !isdigit(*params))
+		return -EINVAL;
+
+	dev_id = strtoul(params, &end_param, 0);
+	if (*end_param != '\0')
+		RTE_DMA_LOG(WARNING, "Extra parameters passed to dmadev telemetry command, ignoring");
+
+	/* Function info_get validates dev_id so we don't need to. */
+	ret = rte_dma_info_get(dev_id, &dma_info);
+	if (ret < 0)
+		return -EINVAL;
+	dev_capa = dma_info.dev_capa;
+
+	rte_tel_data_start_dict(d);
+	rte_tel_data_add_dict_string(d, "name", dma_info.dev_name);
+	rte_tel_data_add_dict_int(d, "nb_vchans", dma_info.nb_vchans);
+	rte_tel_data_add_dict_int(d, "numa_node", dma_info.numa_node);
+	rte_tel_data_add_dict_int(d, "max_vchans", dma_info.max_vchans);
+	rte_tel_data_add_dict_int(d, "max_desc", dma_info.max_desc);
+	rte_tel_data_add_dict_int(d, "min_desc", dma_info.min_desc);
+	rte_tel_data_add_dict_int(d, "max_sges", dma_info.max_sges);
+
+	dma_caps = rte_tel_data_alloc();
+	if (!dma_caps)
+		return -ENOMEM;
+
+	rte_tel_data_start_dict(dma_caps);
+	ADD_CAPA(dma_caps, dev_capa, RTE_DMA_CAPA_MEM_TO_MEM);
+	ADD_CAPA(dma_caps, dev_capa, RTE_DMA_CAPA_MEM_TO_DEV);
+	ADD_CAPA(dma_caps, dev_capa, RTE_DMA_CAPA_DEV_TO_MEM);
+	ADD_CAPA(dma_caps, dev_capa, RTE_DMA_CAPA_DEV_TO_DEV);
+	ADD_CAPA(dma_caps, dev_capa, RTE_DMA_CAPA_SVA);
+	ADD_CAPA(dma_caps, dev_capa, RTE_DMA_CAPA_SILENT);
+	ADD_CAPA(dma_caps, dev_capa, RTE_DMA_CAPA_HANDLES_ERRORS);
+	ADD_CAPA(dma_caps, dev_capa, RTE_DMA_CAPA_OPS_COPY);
+	ADD_CAPA(dma_caps, dev_capa, RTE_DMA_CAPA_OPS_COPY_SG);
+	ADD_CAPA(dma_caps, dev_capa, RTE_DMA_CAPA_OPS_FILL);
+	rte_tel_data_add_dict_container(d, "capabilities", dma_caps, 0);
+
+	return 0;
+}
+
+#define ADD_DICT_STAT(s) rte_tel_data_add_dict_u64(d, #s, dma_stats.s)
+
+static int
+dmadev_handle_dev_stats(const char *cmd __rte_unused,
+		const char *params,
+		struct rte_tel_data *d)
+{
+	struct rte_dma_info dma_info;
+	struct rte_dma_stats dma_stats;
+	int dev_id, ret, vchan_id;
+	char *end_param;
+	const char *vchan_param;
+
+	if (params == NULL || strlen(params) == 0 || !isdigit(*params))
+		return -EINVAL;
+
+	dev_id = strtoul(params, &end_param, 0);
+
+	/* Function info_get validates dev_id so we don't need to. */
+	ret = rte_dma_info_get(dev_id, &dma_info);
+	if (ret < 0)
+		return -EINVAL;
+
+	/* If the device has one vchan the user does not need to supply the
+	 * vchan id and only the device id is needed, no extra parameters.
+	 */
+	if (dma_info.nb_vchans == 1 && *end_param == '\0')
+		vchan_id = 0;
+	else {
+		vchan_param = strtok(end_param, ",");
+		if (!vchan_param || strlen(vchan_param) == 0 || !isdigit(*vchan_param))
+			return -EINVAL;
+
+		vchan_id = strtoul(vchan_param, &end_param, 0);
+	}
+	if (*end_param != '\0')
+		RTE_DMA_LOG(WARNING, "Extra parameters passed to dmadev telemetry command, ignoring");
+
+	ret = rte_dma_stats_get(dev_id, vchan_id, &dma_stats);
+	if (ret < 0)
+		return -EINVAL;
+
+	rte_tel_data_start_dict(d);
+	ADD_DICT_STAT(submitted);
+	ADD_DICT_STAT(completed);
+	ADD_DICT_STAT(errors);
+
+	return 0;
+}
+
+RTE_INIT(dmadev_init_telemetry)
+{
+	rte_telemetry_register_cmd("/dmadev/list", dmadev_handle_dev_list,
+			"Returns list of available dmadev devices by IDs. No parameters.");
+	rte_telemetry_register_cmd("/dmadev/info", dmadev_handle_dev_info,
+			"Returns information for a dmadev. Parameters: int dev_id");
+	rte_telemetry_register_cmd("/dmadev/stats", dmadev_handle_dev_stats,
+			"Returns the stats for a dmadev vchannel. Parameters: int dev_id, vchan_id (Optional if only one vchannel)");
+}