devlink: introduce framework for selftests

Add a framework for running selftests.
Framework exposes devlink commands and test suite(s) to the user
to execute and query the supported tests by the driver.

Below are new entries in devlink_nl_ops
devlink_nl_cmd_selftests_show: To query the supported selftests
by the driver.
devlink_nl_cmd_selftests_run: To execute selftests. Users can
provide a test mask for executing group tests or standalone tests.

Documentation/networking/devlink/ path is already part of MAINTAINERS &
the new files come under this path. Hence no update needed to the
MAINTAINERS

Signed-off-by: Vikas Gupta <vikas.gupta@broadcom.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>

Documentation/networking/devlink/devlink-selftests.rst

@@ -0,0 +1,34 @@
+.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+
+=================
+Devlink Selftests
+=================
+
+The ``devlink-selftests`` API allows executing selftests on the device.
+
+Tests Mask
+==========
+The ``devlink-selftests`` command should be run with a mask indicating
+the tests to be executed.
+
+Tests Description
+=================
+The following is a list of tests that drivers may execute.
+
+.. list-table:: List of tests
+   :widths: 5 90
+
+   * - Name
+     - Description
+   * - ``DEVLINK_SELFTEST_FLASH``
+     - Runs a flash test on the device.
+
+example usage
+-------------
+
+.. code:: shell
+
+    # Query selftests supported on the device
+    $ devlink dev selftests show DEV
+    # Executes selftests on the device
+    $ devlink dev selftests run DEV test {flash | all}

include/net/devlink.h

@@ -1215,6 +1215,18 @@ enum {
 	DEVLINK_F_RELOAD = 1UL << 0,
 };
 
+#define DEVLINK_SELFTEST_FLASH_TEST_NAME "flash"
+
+static inline const char *devlink_selftest_name(int test)
+{
+	switch (test) {
+	case DEVLINK_SELFTEST_FLASH_BIT:
+		return DEVLINK_SELFTEST_FLASH_TEST_NAME;
+	default:
+		return "unknown";
+	}
+}
+
 struct devlink_ops {
 	/**
 	 * @supported_flash_update_params:
@@ -1509,6 +1521,24 @@ struct devlink_ops {
 				    struct devlink_rate *parent,
 				    void *priv_child, void *priv_parent,
 				    struct netlink_ext_ack *extack);
+	/**
+	 * selftests_show() - Shows selftests supported by device
+	 * @devlink: Devlink instance
+	 * @extack: extack for reporting error messages
+	 *
+	 * Return: test mask supported by driver
+	 */
+	u32 (*selftests_show)(struct devlink *devlink,
+			      struct netlink_ext_ack *extack);
+	/**
+	 * selftests_run() - Runs selftests
+	 * @devlink: Devlink instance
+	 * @tests_mask: tests to be run by driver
+	 * @results: test results by driver
+	 * @extack: extack for reporting error messages
+	 */
+	void (*selftests_run)(struct devlink *devlink, u32 tests_mask,
+			      u8 *results, struct netlink_ext_ack *extack);
 };
 
 void *devlink_priv(struct devlink *devlink);

include/uapi/linux/devlink.h

@@ -136,6 +136,9 @@ enum devlink_command {
 	DEVLINK_CMD_LINECARD_NEW,
 	DEVLINK_CMD_LINECARD_DEL,
 
+	DEVLINK_CMD_SELFTESTS_SHOW,
+	DEVLINK_CMD_SELFTESTS_RUN,
+
 	/* add new commands above here */
 	__DEVLINK_CMD_MAX,
 	DEVLINK_CMD_MAX = __DEVLINK_CMD_MAX - 1
@@ -276,6 +279,25 @@ enum {
 #define DEVLINK_SUPPORTED_FLASH_OVERWRITE_SECTIONS \
 	(_BITUL(__DEVLINK_FLASH_OVERWRITE_MAX_BIT) - 1)
 
+/* Commonly used test cases */
+enum {
+	DEVLINK_SELFTEST_FLASH_BIT,
+
+	__DEVLINK_SELFTEST_MAX_BIT,
+	DEVLINK_SELFTEST_MAX_BIT = __DEVLINK_SELFTEST_MAX_BIT - 1
+};
+
+#define DEVLINK_SELFTEST_FLASH _BITUL(DEVLINK_SELFTEST_FLASH_BIT)
+
+#define DEVLINK_SELFTESTS_MASK \
+	(_BITUL(__DEVLINK_SELFTEST_MAX_BIT) - 1)
+
+enum {
+	DEVLINK_SELFTEST_SKIP,
+	DEVLINK_SELFTEST_PASS,
+	DEVLINK_SELFTEST_FAIL
+};
+
 /**
  * enum devlink_trap_action - Packet trap action.
  * @DEVLINK_TRAP_ACTION_DROP: Packet is dropped by the device and a copy is not
@@ -576,6 +598,10 @@ enum devlink_attr {
 	DEVLINK_ATTR_LINECARD_TYPE,		/* string */
 	DEVLINK_ATTR_LINECARD_SUPPORTED_TYPES,	/* nested */
 
+	DEVLINK_ATTR_SELFTESTS_MASK,		/* u32 */
+	DEVLINK_ATTR_TEST_RESULT,		/* nested */
+	DEVLINK_ATTR_TEST_NAME,			/* string */
+	DEVLINK_ATTR_TEST_RESULT_VAL,		/* u8 */
 	/* add new attributes above here, update the policy in devlink.c */
 
 	__DEVLINK_ATTR_MAX,

net/core/devlink.c

@@ -4794,6 +4794,136 @@ static int devlink_nl_cmd_flash_update(struct sk_buff *skb,
 	return ret;
 }
 
+static int devlink_selftest_name_put(struct sk_buff *skb, int test)
+{
+	const char *name = devlink_selftest_name(test);
+	if (nla_put_string(skb, DEVLINK_ATTR_TEST_NAME, name))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static int devlink_nl_cmd_selftests_show(struct sk_buff *skb,
+					 struct genl_info *info)
+{
+	struct devlink *devlink = info->user_ptr[0];
+	struct sk_buff *msg;
+	unsigned long tests;
+	int err = 0;
+	void *hdr;
+	int test;
+
+	if (!devlink->ops->selftests_show)
+		return -EOPNOTSUPP;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
+			  &devlink_nl_family, 0, DEVLINK_CMD_SELFTESTS_SHOW);
+	if (!hdr)
+		goto free_msg;
+
+	if (devlink_nl_put_handle(msg, devlink))
+		goto genlmsg_cancel;
+
+	tests = devlink->ops->selftests_show(devlink, info->extack);
+
+	for_each_set_bit(test, &tests, __DEVLINK_SELFTEST_MAX_BIT) {
+		err = devlink_selftest_name_put(msg, test);
+		if (err)
+			goto genlmsg_cancel;
+	}
+
+	genlmsg_end(msg, hdr);
+
+	return genlmsg_reply(msg, info);
+
+genlmsg_cancel:
+	genlmsg_cancel(msg, hdr);
+free_msg:
+	nlmsg_free(msg);
+	return err;
+}
+
+static int devlink_selftest_result_put(struct sk_buff *skb, int test,
+				       u8 result)
+{
+	const char *name = devlink_selftest_name(test);
+	struct nlattr *result_attr;
+
+	result_attr = nla_nest_start_noflag(skb, DEVLINK_ATTR_TEST_RESULT);
+	if (!result_attr)
+		return -EMSGSIZE;
+
+	if (nla_put_string(skb, DEVLINK_ATTR_TEST_NAME, name) ||
+	    nla_put_u8(skb, DEVLINK_ATTR_TEST_RESULT_VAL, result))
+		goto nla_put_failure;
+
+	nla_nest_end(skb, result_attr);
+
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(skb, result_attr);
+	return -EMSGSIZE;
+}
+
+static int devlink_nl_cmd_selftests_run(struct sk_buff *skb,
+					struct genl_info *info)
+{
+	u8 test_results[DEVLINK_SELFTEST_MAX_BIT + 1] = {};
+	struct devlink *devlink = info->user_ptr[0];
+	unsigned long tests;
+	struct sk_buff *msg;
+	u32 tests_mask;
+	void *hdr;
+	int err = 0;
+	int test;
+
+	if (!devlink->ops->selftests_run)
+		return -EOPNOTSUPP;
+
+	if (!info->attrs[DEVLINK_ATTR_SELFTESTS_MASK])
+		return -EINVAL;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
+			  &devlink_nl_family, 0, DEVLINK_CMD_SELFTESTS_RUN);
+	if (!hdr)
+		goto free_msg;
+
+	if (devlink_nl_put_handle(msg, devlink))
+		goto genlmsg_cancel;
+
+	tests_mask = nla_get_u32(info->attrs[DEVLINK_ATTR_SELFTESTS_MASK]);
+
+	devlink->ops->selftests_run(devlink, tests_mask, test_results,
+				    info->extack);
+	tests = tests_mask;
+
+	for_each_set_bit(test, &tests, __DEVLINK_SELFTEST_MAX_BIT) {
+		err = devlink_selftest_result_put(msg, test,
+						  test_results[test]);
+		if (err)
+			goto genlmsg_cancel;
+	}
+
+	genlmsg_end(msg, hdr);
+
+	return genlmsg_reply(msg, info);
+
+genlmsg_cancel:
+	genlmsg_cancel(msg, hdr);
+free_msg:
+	nlmsg_free(msg);
+	return err;
+}
+
 static const struct devlink_param devlink_param_generic[] = {
 	{
 		.id = DEVLINK_PARAM_GENERIC_ID_INT_ERR_RESET,
@@ -9000,6 +9130,8 @@ static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
 	[DEVLINK_ATTR_RATE_PARENT_NODE_NAME] = { .type = NLA_NUL_STRING },
 	[DEVLINK_ATTR_LINECARD_INDEX] = { .type = NLA_U32 },
 	[DEVLINK_ATTR_LINECARD_TYPE] = { .type = NLA_NUL_STRING },
+	[DEVLINK_ATTR_SELFTESTS_MASK] = NLA_POLICY_MASK(NLA_U32,
+							DEVLINK_SELFTESTS_MASK),
 };
 
 static const struct genl_small_ops devlink_nl_ops[] = {
@@ -9361,6 +9493,18 @@ static const struct genl_small_ops devlink_nl_ops[] = {
 		.doit = devlink_nl_cmd_trap_policer_set_doit,
 		.flags = GENL_ADMIN_PERM,
 	},
+	{
+		.cmd = DEVLINK_CMD_SELFTESTS_SHOW,
+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.doit = devlink_nl_cmd_selftests_show,
+		.flags = GENL_ADMIN_PERM,
+	},
+	{
+		.cmd = DEVLINK_CMD_SELFTESTS_RUN,
+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.doit = devlink_nl_cmd_selftests_run,
+		.flags = GENL_ADMIN_PERM,
+	},
 };
 
 static struct genl_family devlink_nl_family __ro_after_init = {