Merge pull request #15036 from yuwata/can-termination-mod

network: add CAN Termination tristate option

docs/USER_RECORD.md

@@ -14,7 +14,7 @@ pairs, encoded as JSON. Specifically:
 1. [`systemd-homed.service`](https://www.freedesktop.org/software/systemd/man/systemd-homed.service.html)
    manages `human` user home directories and embeds these JSON records
    directly in the home directory images (see [Home
-   Directories](https://systemd.io/HOME_DIRECTORY)) for details.
+   Directories](https://systemd.io/HOME_DIRECTORY) for details).
 
 2. [`pam_systemd`](https://www.freedesktop.org/software/systemd/man/pam_systemd.html)
    processes these JSON records for users that log in, and applies various
@@ -541,7 +541,7 @@ below). It's undefined how precise the URI is: during log-in it is tested
 against all plugged in security tokens and if there's exactly one matching
 private key found with it it is used.
 
-`privileged` → An object, which contains the fields of he `privileged` section
+`privileged` → An object, which contains the fields of the `privileged` section
 of the user record, see below.
 
 `perMachine` → An array of objects, which contain the `perMachine` section of

man/systemd.network.xml

@@ -2303,6 +2303,13 @@
             automatic restart off. By default automatic restart is disabled.</para>
           </listitem>
         </varlistentry>
+        <varlistentry>
+          <term><varname>Termination=</varname></term>
+          <listitem>
+            <para>Takes a boolean. When <literal>yes</literal>, the termination resistor will be selected for
+            the bias network. When unset, the kernel's default will be used.</para>
+          </listitem>
+        </varlistentry>
         <varlistentry>
           <term><varname>TripleSampling=</varname></term>
           <listitem>

src/basic/linux/can/netlink.h

@@ -0,0 +1,144 @@
+/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
+/*
+ * linux/can/netlink.h
+ *
+ * Definitions for the CAN netlink interface
+ *
+ * Copyright (c) 2009 Wolfgang Grandegger <wg@grandegger.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the version 2 of the GNU General Public License
+ * as published by the Free Software Foundation
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef _UAPI_CAN_NETLINK_H
+#define _UAPI_CAN_NETLINK_H
+
+#include <linux/types.h>
+
+/*
+ * CAN bit-timing parameters
+ *
+ * For further information, please read chapter "8 BIT TIMING
+ * REQUIREMENTS" of the "Bosch CAN Specification version 2.0"
+ * at http://www.semiconductors.bosch.de/pdf/can2spec.pdf.
+ */
+struct can_bittiming {
+	__u32 bitrate;		/* Bit-rate in bits/second */
+	__u32 sample_point;	/* Sample point in one-tenth of a percent */
+	__u32 tq;		/* Time quanta (TQ) in nanoseconds */
+	__u32 prop_seg;		/* Propagation segment in TQs */
+	__u32 phase_seg1;	/* Phase buffer segment 1 in TQs */
+	__u32 phase_seg2;	/* Phase buffer segment 2 in TQs */
+	__u32 sjw;		/* Synchronisation jump width in TQs */
+	__u32 brp;		/* Bit-rate prescaler */
+};
+
+/*
+ * CAN hardware-dependent bit-timing constant
+ *
+ * Used for calculating and checking bit-timing parameters
+ */
+struct can_bittiming_const {
+	char name[16];		/* Name of the CAN controller hardware */
+	__u32 tseg1_min;	/* Time segment 1 = prop_seg + phase_seg1 */
+	__u32 tseg1_max;
+	__u32 tseg2_min;	/* Time segment 2 = phase_seg2 */
+	__u32 tseg2_max;
+	__u32 sjw_max;		/* Synchronisation jump width */
+	__u32 brp_min;		/* Bit-rate prescaler */
+	__u32 brp_max;
+	__u32 brp_inc;
+};
+
+/*
+ * CAN clock parameters
+ */
+struct can_clock {
+	__u32 freq;		/* CAN system clock frequency in Hz */
+};
+
+/*
+ * CAN operational and error states
+ */
+enum can_state {
+	CAN_STATE_ERROR_ACTIVE = 0,	/* RX/TX error count < 96 */
+	CAN_STATE_ERROR_WARNING,	/* RX/TX error count < 128 */
+	CAN_STATE_ERROR_PASSIVE,	/* RX/TX error count < 256 */
+	CAN_STATE_BUS_OFF,		/* RX/TX error count >= 256 */
+	CAN_STATE_STOPPED,		/* Device is stopped */
+	CAN_STATE_SLEEPING,		/* Device is sleeping */
+	CAN_STATE_MAX
+};
+
+/*
+ * CAN bus error counters
+ */
+struct can_berr_counter {
+	__u16 txerr;
+	__u16 rxerr;
+};
+
+/*
+ * CAN controller mode
+ */
+struct can_ctrlmode {
+	__u32 mask;
+	__u32 flags;
+};
+
+#define CAN_CTRLMODE_LOOPBACK		0x01	/* Loopback mode */
+#define CAN_CTRLMODE_LISTENONLY		0x02	/* Listen-only mode */
+#define CAN_CTRLMODE_3_SAMPLES		0x04	/* Triple sampling mode */
+#define CAN_CTRLMODE_ONE_SHOT		0x08	/* One-Shot mode */
+#define CAN_CTRLMODE_BERR_REPORTING	0x10	/* Bus-error reporting */
+#define CAN_CTRLMODE_FD			0x20	/* CAN FD mode */
+#define CAN_CTRLMODE_PRESUME_ACK	0x40	/* Ignore missing CAN ACKs */
+#define CAN_CTRLMODE_FD_NON_ISO		0x80	/* CAN FD in non-ISO mode */
+
+/*
+ * CAN device statistics
+ */
+struct can_device_stats {
+	__u32 bus_error;	/* Bus errors */
+	__u32 error_warning;	/* Changes to error warning state */
+	__u32 error_passive;	/* Changes to error passive state */
+	__u32 bus_off;		/* Changes to bus off state */
+	__u32 arbitration_lost; /* Arbitration lost errors */
+	__u32 restarts;		/* CAN controller re-starts */
+};
+
+/*
+ * CAN netlink interface
+ */
+enum {
+	IFLA_CAN_UNSPEC,
+	IFLA_CAN_BITTIMING,
+	IFLA_CAN_BITTIMING_CONST,
+	IFLA_CAN_CLOCK,
+	IFLA_CAN_STATE,
+	IFLA_CAN_CTRLMODE,
+	IFLA_CAN_RESTART_MS,
+	IFLA_CAN_RESTART,
+	IFLA_CAN_BERR_COUNTER,
+	IFLA_CAN_DATA_BITTIMING,
+	IFLA_CAN_DATA_BITTIMING_CONST,
+	IFLA_CAN_TERMINATION,
+	IFLA_CAN_TERMINATION_CONST,
+	IFLA_CAN_BITRATE_CONST,
+	IFLA_CAN_DATA_BITRATE_CONST,
+	IFLA_CAN_BITRATE_MAX,
+	__IFLA_CAN_MAX
+};
+
+#define IFLA_CAN_MAX	(__IFLA_CAN_MAX - 1)
+
+/* u16 termination range: 1..65535 Ohms */
+#define CAN_TERMINATION_DISABLED 0
+
+#endif /* !_UAPI_CAN_NETLINK_H */

src/libsystemd/sd-netlink/netlink-types.c

@@ -316,6 +316,7 @@ static const NLType rtnl_link_info_data_can_types[] = {
         [IFLA_CAN_BITTIMING]            = { .size = sizeof(struct can_bittiming) },
         [IFLA_CAN_RESTART_MS]           = { .type = NETLINK_TYPE_U32 },
         [IFLA_CAN_CTRLMODE]             = { .size = sizeof(struct can_ctrlmode) },
+        [IFLA_CAN_TERMINATION]          = { .type = NETLINK_TYPE_U16 },
 };
 
 static const NLType rtnl_link_info_data_macsec_types[] = {

src/network/networkd-can.c

@@ -9,6 +9,8 @@
 #include "networkd-manager.h"
 #include "string-util.h"
 
+#define CAN_TERMINATION_OHM_VALUE 120
+
 static int link_up_handler(sd_netlink *rtnl, sd_netlink_message *m, Link *link) {
         int r;
 
@@ -152,6 +154,17 @@ static int link_set_can(Link *link) {
                         return log_link_error_errno(link, r, "Could not append IFLA_CAN_CTRLMODE attribute: %m");
         }
 
+        if (link->network->can_termination >= 0) {
+
+                log_link_debug(link, "%sabling can-termination", link->network->can_termination ? "En" : "Dis");
+
+                r = sd_netlink_message_append_u16(m, IFLA_CAN_TERMINATION,
+                                link->network->can_termination ? CAN_TERMINATION_OHM_VALUE : 0);
+                if (r < 0)
+                        return log_link_error_errno(link, r, "Could not append IFLA_CAN_TERMINATION attribute: %m");
+
+        }
+
         r = sd_netlink_message_close_container(m);
         if (r < 0)
                 return log_link_error_errno(link, r, "Failed to close netlink container: %m");

src/network/networkd-network-gperf.gperf

@@ -255,6 +255,7 @@ CAN.BitRate,                                 config_parse_si_uint64,
 CAN.SamplePoint,                             config_parse_permille,                                    0,                             offsetof(Network, can_sample_point)
 CAN.RestartSec,                              config_parse_sec,                                         0,                             offsetof(Network, can_restart_us)
 CAN.TripleSampling,                          config_parse_tristate,                                    0,                             offsetof(Network, can_triple_sampling)
+CAN.Termination,                             config_parse_tristate,                                    0,                             offsetof(Network, can_termination)
 QDisc.Parent,                                config_parse_qdisc_parent,                                _QDISC_KIND_INVALID,           0
 QDisc.Handle,                                config_parse_qdisc_handle,                                _QDISC_KIND_INVALID,           0
 CAKE.Parent,                                 config_parse_qdisc_parent,                                QDISC_KIND_CAKE,               0

src/network/networkd-network.c

@@ -457,6 +457,7 @@ int network_load_one(Manager *manager, OrderedHashmap **networks, const char *fi
                 .keep_configuration = _KEEP_CONFIGURATION_INVALID,
 
                 .can_triple_sampling = -1,
+                .can_termination = -1,
                 .ip_service_type = -1,
         };
 

src/network/networkd-network.h

@@ -199,6 +199,7 @@ struct Network {
         unsigned can_sample_point;
         usec_t can_restart_us;
         int can_triple_sampling;
+        int can_termination;
 
         AddressFamily ip_forward;
         bool ip_masquerade;

test/fuzz/fuzz-network-parser/directives.network

@@ -200,6 +200,7 @@ SamplePoint=
 BitRate=
 RestartSec=
 TripleSampling=
+Termination=
 [Address]
 DuplicateAddressDetection=
 AutoJoin=