[dpdk-dev] [PATCH] librte_ethdev: extend dpdk api led control to query capability

[Laurent Hardy <laurent.hardy@6wind.com>]

In current led control API we have no way to know if a device is able
to handle on/off requests coming from the application.
Knowing if the device is led control capable could be useful to avoid
exchanges between application and kernel.
Using the on/off requests to flag if the device is led control capable
(based on the ENOSUP returned error) is not convenient as such request
can change the led state on device.

This patch adds a new function rte_eth_led_ctrl_capable() that will look
for led_off/on dev ops availability on the related pmd, to know if the
device is able to handle such led control requests (on/off).

Signed-off-by: Laurent Hardy <laurent.hardy@6wind.com>
---
 doc/guides/nics/features.rst             |  5 +++++
 lib/librte_ethdev/rte_ethdev.c           | 12 ++++++++++++
 lib/librte_ethdev/rte_ethdev.h           | 15 +++++++++++++++
 lib/librte_ethdev/rte_ethdev_core.h      |  4 ++++
 lib/librte_ethdev/rte_ethdev_version.map |  1 +
 5 files changed, 37 insertions(+)

diff --git a/doc/guides/nics/features.rst b/doc/guides/nics/features.rst
index 8394a6595..012645dc5 100644
--- a/doc/guides/nics/features.rst
+++ b/doc/guides/nics/features.rst
@@ -732,6 +732,11 @@ registers and register size).
 LED
 ---
 
+Interrogates device to know if it is led control capable.
+
+* **[implements] eth_dev_ops**: ``dev_led_ctrl_capable``.
+* **[related]    API**: ``rte_eth_led_ctrl_capable()``.
+
 Supports turning on/off a software controllable LED on a device.
 
 * **[implements] eth_dev_ops**: ``dev_led_on``, ``dev_led_off``.
diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
index 6e9cb243e..b259b6b19 100644
--- a/lib/librte_ethdev/rte_ethdev.c
+++ b/lib/librte_ethdev/rte_ethdev.c
@@ -3612,6 +3612,18 @@ rte_eth_led_off(uint16_t port_id)
 	return eth_err(port_id, (*dev->dev_ops->dev_led_off)(dev));
 }
 
+int
+rte_eth_led_ctrl_capable(uint16_t port_id)
+{
+	struct rte_eth_dev *dev;
+
+	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
+	dev = &rte_eth_devices[port_id];
+	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_led_off, -ENOTSUP);
+	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_led_on, -ENOTSUP);
+	return 0;
+}
+
 /*
  * Returns index into MAC address array of addr. Use 00:00:00:00:00:00 to find
  * an empty spot.
diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
index 18a9defc2..a5bacd643 100644
--- a/lib/librte_ethdev/rte_ethdev.h
+++ b/lib/librte_ethdev/rte_ethdev.h
@@ -3204,6 +3204,21 @@ int  rte_eth_led_on(uint16_t port_id);
  */
 int  rte_eth_led_off(uint16_t port_id);
 
+/**
+ * Interrogate the Ethernet device to know if it is led control capable.
+ *
+ * @param port_id
+ *   The port identifier of the Ethernet device.
+ * @return
+ *   - (0) if successful.
+ *   - (-ENOTSUP) if underlying hardware OR driver doesn't support
+ *     that operation.
+ *   - (-ENODEV) if *port_id* invalid.
+ *   - (-EIO) if device is removed.
+ */
+int  __rte_experimental
+rte_eth_led_ctrl_capable(uint16_t port_id);
+
 /**
  * Get current status of the Ethernet link flow control for Ethernet device
  *
diff --git a/lib/librte_ethdev/rte_ethdev_core.h b/lib/librte_ethdev/rte_ethdev_core.h
index 7bf97e24e..6cf2a5242 100644
--- a/lib/librte_ethdev/rte_ethdev_core.h
+++ b/lib/librte_ethdev/rte_ethdev_core.h
@@ -388,6 +388,9 @@ typedef int (*eth_dev_led_on_t)(struct rte_eth_dev *dev);
 typedef int (*eth_dev_led_off_t)(struct rte_eth_dev *dev);
 /**< @internal Turn off SW controllable LED on an Ethernet device */
 
+typedef int (*eth_dev_led_ctrl_capable_t)(struct rte_eth_dev *dev);
+/**< @internal Get led control capability on an Ethernet device */
+
 typedef void (*eth_mac_addr_remove_t)(struct rte_eth_dev *dev, uint32_t index);
 /**< @internal Remove MAC address from receive address register */
 
@@ -675,6 +678,7 @@ struct eth_dev_ops {
 
 	eth_dev_led_on_t           dev_led_on;    /**< Turn on LED. */
 	eth_dev_led_off_t          dev_led_off;   /**< Turn off LED. */
+	eth_dev_led_ctrl_capable_t dev_led_ctrl_capable;  /**< Get led control capability. */
 
 	flow_ctrl_get_t            flow_ctrl_get; /**< Get flow control. */
 	flow_ctrl_set_t            flow_ctrl_set; /**< Setup flow control. */
diff --git a/lib/librte_ethdev/rte_ethdev_version.map b/lib/librte_ethdev/rte_ethdev_version.map
index a7dacf2cf..776f3b5d6 100644
--- a/lib/librte_ethdev/rte_ethdev_version.map
+++ b/lib/librte_ethdev/rte_ethdev_version.map
@@ -227,4 +227,5 @@ EXPERIMENTAL {
 	rte_flow_dynf_metadata_mask;
 	rte_flow_dynf_metadata_register;
 	rte_eth_dev_set_ptypes;
+	rte_eth_led_ctrl_capable;
 };
-- 
2.20.1