tools/lib/thermal: Add a thermal library

The thermal framework implements a netlink notification mechanism to
be used by the userspace to have a thermal configuration discovery,
trip point changes or violation, cooling device changes notifications,
etc...

This library provides a level of abstraction for the thermal netlink
notification allowing the userspace to connect to the notification
mechanism more easily. The library is callback oriented.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://lore.kernel.org/r/20220420160933.347088-2-daniel.lezcano@linaro.org

1 files changed, 215 insertions, 0 deletions

diff --git a/tools/lib/thermal/thermal_nl.c b/tools/lib/thermal/thermal_nl.c
new file mode 100644
index 000000000000..b05cf9569858
--- /dev/null
+++ b/tools/lib/thermal/thermal_nl.c
@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: LGPL-2.1+
+// Copyright (C) 2022, Linaro Ltd - Daniel Lezcano <daniel.lezcano@linaro.org>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <thermal.h>
+#include "thermal_nl.h"
+
+struct handler_args {
+	const char *group;
+	int id;
+};
+
+static __thread int err;
+static __thread int done;
+
+static int nl_seq_check_handler(struct nl_msg *msg, void *arg)
+{
+	return NL_OK;
+}
+
+static int nl_error_handler(struct sockaddr_nl *nla, struct nlmsgerr *nl_err,
+			    void *arg)
+{
+	int *ret = arg;
+
+	if (ret)
+		*ret = nl_err->error;
+
+	return NL_STOP;
+}
+
+static int nl_finish_handler(struct nl_msg *msg, void *arg)
+{
+	int *ret = arg;
+
+	if (ret)
+		*ret = 1;
+
+	return NL_OK;
+}
+
+static int nl_ack_handler(struct nl_msg *msg, void *arg)
+{
+	int *ret = arg;
+
+	if (ret)
+		*ret = 1;
+
+	return NL_OK;
+}
+
+int nl_send_msg(struct nl_sock *sock, struct nl_cb *cb, struct nl_msg *msg,
+		int (*rx_handler)(struct nl_msg *, void *), void *data)
+{
+	if (!rx_handler)
+		return THERMAL_ERROR;
+
+	err = nl_send_auto_complete(sock, msg);
+	if (err < 0)
+		return err;
+
+	nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, rx_handler, data);
+
+	err = done = 0;
+
+	while (err == 0 && done == 0)
+		nl_recvmsgs(sock, cb);
+
+	return err;
+}
+
+static int nl_family_handler(struct nl_msg *msg, void *arg)
+{
+	struct handler_args *grp = arg;
+	struct nlattr *tb[CTRL_ATTR_MAX + 1];
+	struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
+	struct nlattr *mcgrp;
+	int rem_mcgrp;
+
+	nla_parse(tb, CTRL_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
+		  genlmsg_attrlen(gnlh, 0), NULL);
+
+	if (!tb[CTRL_ATTR_MCAST_GROUPS])
+		return THERMAL_ERROR;
+
+	nla_for_each_nested(mcgrp, tb[CTRL_ATTR_MCAST_GROUPS], rem_mcgrp) {
+
+		struct nlattr *tb_mcgrp[CTRL_ATTR_MCAST_GRP_MAX + 1];
+
+		nla_parse(tb_mcgrp, CTRL_ATTR_MCAST_GRP_MAX,
+			  nla_data(mcgrp), nla_len(mcgrp), NULL);
+
+		if (!tb_mcgrp[CTRL_ATTR_MCAST_GRP_NAME] ||
+		    !tb_mcgrp[CTRL_ATTR_MCAST_GRP_ID])
+			continue;
+
+		if (strncmp(nla_data(tb_mcgrp[CTRL_ATTR_MCAST_GRP_NAME]),
+			    grp->group,
+			    nla_len(tb_mcgrp[CTRL_ATTR_MCAST_GRP_NAME])))
+			continue;
+
+		grp->id = nla_get_u32(tb_mcgrp[CTRL_ATTR_MCAST_GRP_ID]);
+
+		break;
+	}
+
+	return THERMAL_SUCCESS;
+}
+
+static int nl_get_multicast_id(struct nl_sock *sock, struct nl_cb *cb,
+			       const char *family, const char *group)
+{
+	struct nl_msg *msg;
+	int ret = 0, ctrlid;
+	struct handler_args grp = {
+		.group = group,
+		.id = -ENOENT,
+	};
+
+	msg = nlmsg_alloc();
+	if (!msg)
+		return THERMAL_ERROR;
+
+	ctrlid = genl_ctrl_resolve(sock, "nlctrl");
+
+	genlmsg_put(msg, 0, 0, ctrlid, 0, 0, CTRL_CMD_GETFAMILY, 0);
+
+	nla_put_string(msg, CTRL_ATTR_FAMILY_NAME, family);
+
+	ret = nl_send_msg(sock, cb, msg, nl_family_handler, &grp);
+	if (ret)
+		goto nla_put_failure;
+
+	ret = grp.id;
+
+nla_put_failure:
+	nlmsg_free(msg);
+	return ret;
+}
+
+int nl_thermal_connect(struct nl_sock **nl_sock, struct nl_cb **nl_cb)
+{
+	struct nl_cb *cb;
+	struct nl_sock *sock;
+
+	cb = nl_cb_alloc(NL_CB_DEFAULT);
+	if (!cb)
+		return THERMAL_ERROR;
+
+	sock = nl_socket_alloc();
+	if (!sock)
+		goto out_cb_free;
+
+	if (genl_connect(sock))
+		goto out_socket_free;
+
+	if (nl_cb_err(cb, NL_CB_CUSTOM, nl_error_handler, &err) ||
+	    nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, nl_finish_handler, &done) ||
+	    nl_cb_set(cb, NL_CB_ACK, NL_CB_CUSTOM, nl_ack_handler, &done) ||
+	    nl_cb_set(cb, NL_CB_SEQ_CHECK, NL_CB_CUSTOM, nl_seq_check_handler, &done))
+		return THERMAL_ERROR;
+
+	*nl_sock = sock;
+	*nl_cb = cb;
+
+	return THERMAL_SUCCESS;
+
+out_socket_free:
+	nl_socket_free(sock);
+out_cb_free:
+	nl_cb_put(cb);
+	return THERMAL_ERROR;
+}
+
+void nl_thermal_disconnect(struct nl_sock *nl_sock, struct nl_cb *nl_cb)
+{
+	nl_close(nl_sock);
+	nl_socket_free(nl_sock);
+	nl_cb_put(nl_cb);
+}
+
+int nl_unsubscribe_thermal(struct nl_sock *nl_sock, struct nl_cb *nl_cb,
+			   const char *group)
+{
+	int mcid;
+
+	mcid = nl_get_multicast_id(nl_sock, nl_cb, THERMAL_GENL_FAMILY_NAME,
+				   group);
+	if (mcid < 0)
+		return THERMAL_ERROR;
+
+	if (nl_socket_drop_membership(nl_sock, mcid))
+		return THERMAL_ERROR;
+
+	return THERMAL_SUCCESS;
+}
+
+int nl_subscribe_thermal(struct nl_sock *nl_sock, struct nl_cb *nl_cb,
+			 const char *group)
+{
+	int mcid;
+
+	mcid = nl_get_multicast_id(nl_sock, nl_cb, THERMAL_GENL_FAMILY_NAME,
+				   group);
+	if (mcid < 0)
+		return THERMAL_ERROR;
+
+	if (nl_socket_add_membership(nl_sock, mcid))
+		return THERMAL_ERROR;
+
+	return THERMAL_SUCCESS;
+}