@@ -171,6 +171,16 @@ config CAN_KVASER_PCIEFD
Kvaser M.2 PCIe 4xCAN
Kvaser PCIe 8xCAN
+config CAN_LIN
+ tristate "LIN mode support"
+ help
+ This is a glue driver for LIN-BUS support.
+
+ The local interconnect (LIN) bus is a simple bus with a feature
+ subset of CAN. It is often combined with CAN for simple controls.
+
+ Actual device drivers need to be enabled too.
+
config CAN_SLCAN
tristate "Serial / USB serial CAN Adaptors (slcan)"
depends on TTY
@@ -25,6 +25,7 @@ obj-$(CONFIG_CAN_GRCAN) += grcan.o
obj-$(CONFIG_CAN_IFI_CANFD) += ifi_canfd/
obj-$(CONFIG_CAN_JANZ_ICAN3) += janz-ican3.o
obj-$(CONFIG_CAN_KVASER_PCIEFD) += kvaser_pciefd.o
+obj-$(CONFIG_CAN_LIN) += lin.o
obj-$(CONFIG_CAN_MSCAN) += mscan/
obj-$(CONFIG_CAN_M_CAN) += m_can/
obj-$(CONFIG_CAN_PEAK_PCIEFD) += peak_canfd/
new file mode 100644
@@ -0,0 +1,495 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Copyright (C) 2024 hexDEV GmbH - https://hexdev.de */
+
+#include <linux/can/core.h>
+#include <linux/can/dev.h>
+#include <linux/can/error.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/netdevice.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <net/lin.h>
+
+static const u8 lin_id_parity_tbl[] = {
+ 0x80, 0xC0, 0x40, 0x00, 0xC0, 0x80, 0x00, 0x40,
+ 0x00, 0x40, 0xC0, 0x80, 0x40, 0x00, 0x80, 0xC0,
+ 0x40, 0x00, 0x80, 0xC0, 0x00, 0x40, 0xC0, 0x80,
+ 0xC0, 0x80, 0x00, 0x40, 0x80, 0xC0, 0x40, 0x00,
+ 0x00, 0x40, 0xC0, 0x80, 0x40, 0x00, 0x80, 0xC0,
+ 0x80, 0xC0, 0x40, 0x00, 0xC0, 0x80, 0x00, 0x40,
+ 0xC0, 0x80, 0x00, 0x40, 0x80, 0xC0, 0x40, 0x00,
+ 0x40, 0x00, 0x80, 0xC0, 0x00, 0x40, 0xC0, 0x80,
+};
+
+u8 lin_get_id_parity(u8 id)
+{
+ return lin_id_parity_tbl[id];
+}
+EXPORT_SYMBOL(lin_get_id_parity);
+
+static ssize_t lin_identifier_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct lin_attr *lin_attr = container_of(attr, struct lin_attr, attr);
+ struct lin_device *ldev = lin_attr->ldev;
+ ssize_t count = 0;
+ struct lin_responder_answer answ;
+ int k, ret;
+ long id;
+
+ if (!ldev->ldev_ops->get_responder_answer)
+ return -EOPNOTSUPP;
+
+ ret = kstrtol(attr->attr.name, 16, &id);
+ if (ret)
+ return ret;
+ if (id < 0 || id >= LIN_NUM_IDS)
+ return -EINVAL;
+
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "%-6s %-11s %-9s %-9s %-2s %-24s %-6s\n",
+ "state", "cksum-mode", "is_event", "event_id",
+ "n", "data", "cksum");
+
+ ret = ldev->ldev_ops->get_responder_answer(ldev, id, &answ);
+ if (ret)
+ return ret;
+
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "%-6s %-11s %-9s %-9u %-2u ",
+ answ.is_active ? "active" : "off",
+ answ.lf.checksum_mode ? "enhanced" : "classic",
+ answ.is_event_frame ? "yes" : "no",
+ answ.event_associated_id,
+ answ.lf.len);
+
+ for (k = 0; k < answ.lf.len; k++)
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "%02x ", answ.lf.data[k]);
+ for (; k < 8; k++)
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ " ");
+ if (answ.lf.len)
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ " %02x", answ.lf.checksum);
+
+ count += scnprintf(buf + count, PAGE_SIZE - count, "\n");
+
+ return count;
+}
+
+static const char *parse_and_advance(const char *buf, long *result,
+ unsigned int base)
+{
+ char num_str[5] = {0};
+ int num_len = 0;
+
+ while (*buf && isspace(*buf))
+ buf++;
+ while (*buf && isalnum(*buf) && num_len < sizeof(num_str) - 1)
+ num_str[num_len++] = *buf++;
+ if (kstrtol(num_str, base, result))
+ return NULL;
+
+ return buf;
+}
+
+static ssize_t lin_identifier_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct lin_attr *lin_attr = container_of(attr, struct lin_attr, attr);
+ struct lin_device *ldev = lin_attr->ldev;
+ struct lin_responder_answer answ = { 0 };
+ const char *ptr = buf;
+ int ret;
+ long v;
+
+ if (!ldev->ldev_ops->update_responder_answer)
+ return -EOPNOTSUPP;
+
+ ret = kstrtol(attr->attr.name, 16, &v);
+ if (ret)
+ return ret;
+ if (v < 0 || v >= LIN_NUM_IDS)
+ return -EINVAL;
+ answ.lf.lin_id = v;
+
+ ptr = parse_and_advance(ptr, &v, 2);
+ if (!ptr)
+ return -EINVAL;
+ answ.is_active = v != 0;
+
+ ptr = parse_and_advance(ptr, &v, 2);
+ if (!ptr)
+ return -EINVAL;
+ answ.lf.checksum_mode = v != 0;
+
+ ptr = parse_and_advance(ptr, &v, 2);
+ if (!ptr)
+ return -EINVAL;
+ answ.is_event_frame = v != 0;
+
+ ptr = parse_and_advance(ptr, &v, 16);
+ if (!ptr || v > LIN_ID_MASK)
+ return -EINVAL;
+ answ.event_associated_id = v;
+
+ ptr = parse_and_advance(ptr, &v, 16);
+ if (!ptr || v > LIN_MAX_DLEN)
+ return -EINVAL;
+ answ.lf.len = v;
+
+ for (int i = 0; i < answ.lf.len; i++) {
+ ptr = parse_and_advance(ptr, &v, 16);
+ if (!ptr)
+ return -EINVAL;
+ answ.lf.data[i] = v;
+ }
+
+ ret = ldev->ldev_ops->update_responder_answer(ldev, &answ);
+ if (ret)
+ return ret;
+
+ return count;
+}
+
+static int lin_create_sysfs_id_files(struct net_device *ndev)
+{
+ struct lin_device *ldev = netdev_priv(ndev);
+ struct kobj_attribute *attr;
+ int ret;
+
+ for (int id = 0; id < LIN_NUM_IDS; id++) {
+ ldev->sysfs_entries[id].ldev = ldev;
+ attr = &ldev->sysfs_entries[id].attr;
+ attr->attr.name = kasprintf(GFP_KERNEL, "%02x", id);
+ if (!attr->attr.name)
+ return -ENOMEM;
+ attr->attr.mode = 0644;
+ attr->show = lin_identifier_show;
+ attr->store = lin_identifier_store;
+
+ sysfs_attr_init(&attr->attr);
+ ret = sysfs_create_file(ldev->lin_ids_kobj, &attr->attr);
+ if (ret) {
+ kfree(attr->attr.name);
+ return -ENOMEM;
+ }
+ }
+
+ return 0;
+}
+
+static void lin_remove_sysfs_id_files(struct net_device *ndev)
+{
+ struct lin_device *ldev = netdev_priv(ndev);
+ struct kobj_attribute *attr;
+
+ for (int id = 0; id < LIN_NUM_IDS; id++) {
+ attr = &ldev->sysfs_entries[id].attr;
+ sysfs_remove_file(ldev->lin_ids_kobj, &attr->attr);
+ kfree(attr->attr.name);
+ }
+}
+
+static void lin_tx_work_handler(struct work_struct *ws)
+{
+ struct lin_device *ldev = container_of(ws, struct lin_device,
+ tx_work);
+ struct net_device *ndev = ldev->ndev;
+ struct canfd_frame *cfd;
+ struct lin_frame lf;
+ int ret;
+
+ ldev->tx_busy = true;
+
+ cfd = (struct canfd_frame *)ldev->tx_skb->data;
+ lf.checksum_mode = (cfd->can_id & LIN_ENHANCED_CKSUM_FLAG) ?
+ LINBUS_ENHANCED : LINBUS_CLASSIC;
+ lf.lin_id = cfd->can_id & LIN_ID_MASK;
+ lf.len = min(cfd->len, LIN_MAX_DLEN);
+ memcpy(lf.data, cfd->data, lf.len);
+
+ ret = ldev->ldev_ops->ldo_tx(ldev, &lf);
+ if (ret) {
+ DEV_STATS_INC(ndev, tx_dropped);
+ netdev_err_once(ndev, "transmission failure %d\n", ret);
+ goto lin_tx_out;
+ }
+
+ DEV_STATS_INC(ndev, tx_packets);
+ DEV_STATS_ADD(ndev, tx_bytes, lf.len);
+
+lin_tx_out:
+ ldev->tx_busy = false;
+ netif_wake_queue(ndev);
+}
+
+static netdev_tx_t lin_start_xmit(struct sk_buff *skb,
+ struct net_device *ndev)
+{
+ struct lin_device *ldev = netdev_priv(ndev);
+
+ if (ldev->tx_busy)
+ return NETDEV_TX_BUSY;
+
+ netif_stop_queue(ndev);
+ ldev->tx_skb = skb;
+ queue_work(ldev->wq, &ldev->tx_work);
+
+ return NETDEV_TX_OK;
+}
+
+static int lin_open(struct net_device *ndev)
+{
+ struct lin_device *ldev = netdev_priv(ndev);
+ int ret;
+
+ ldev->tx_busy = false;
+
+ ret = open_candev(ndev);
+ if (ret)
+ return ret;
+
+ netif_wake_queue(ndev);
+
+ ldev->can.state = CAN_STATE_ERROR_ACTIVE;
+ ndev->mtu = CANFD_MTU;
+
+ return ldev->ldev_ops->ldo_open(ldev);
+}
+
+static int lin_stop(struct net_device *ndev)
+{
+ struct lin_device *ldev = netdev_priv(ndev);
+
+ close_candev(ndev);
+
+ flush_work(&ldev->tx_work);
+
+ ldev->can.state = CAN_STATE_STOPPED;
+
+ return ldev->ldev_ops->ldo_stop(ldev);
+}
+
+static const struct net_device_ops lin_netdev_ops = {
+ .ndo_open = lin_open,
+ .ndo_stop = lin_stop,
+ .ndo_start_xmit = lin_start_xmit,
+ .ndo_change_mtu = can_change_mtu,
+};
+
+u8 lin_get_checksum(u8 pid, u8 n_of_bytes, const u8 *bytes,
+ enum lin_checksum_mode cm)
+{
+ unsigned int csum = 0;
+ int i;
+
+ if (cm == LINBUS_ENHANCED)
+ csum += pid;
+
+ for (i = 0; i < n_of_bytes; i++) {
+ csum += bytes[i];
+ if (csum > 255)
+ csum -= 255;
+ }
+
+ return (~csum & 0xff);
+}
+EXPORT_SYMBOL_GPL(lin_get_checksum);
+
+static int lin_bump_rx_err(struct lin_device *ldev, const struct lin_frame *lf)
+{
+ struct net_device *ndev = ldev->ndev;
+ struct can_frame cf = {0 };
+
+ if (lf->lin_id > LIN_ID_MASK) {
+ netdev_dbg(ndev, "id exceeds LIN max id\n");
+ cf.can_id = CAN_ERR_FLAG | CAN_ERR_PROT;
+ cf.data[3] = CAN_ERR_PROT_LOC_ID12_05;
+ }
+
+ if (lf->len > LIN_MAX_DLEN) {
+ netdev_dbg(ndev, "frame exceeds number of bytes\n");
+ cf.can_id = CAN_ERR_FLAG | CAN_ERR_PROT;
+ cf.data[3] = CAN_ERR_PROT_LOC_DLC;
+ }
+
+ if (lf->len) {
+ u8 checksum = lin_get_checksum(LIN_FORM_PID(lf->lin_id),
+ lf->len, lf->data,
+ lf->checksum_mode);
+
+ if (checksum != lf->checksum) {
+ netdev_dbg(ndev, "expected cksm: 0x%02x got: 0x%02x\n",
+ checksum, lf->checksum);
+ cf.can_id = CAN_ERR_FLAG | CAN_ERR_PROT;
+ cf.data[2] = CAN_ERR_PROT_FORM;
+ }
+ }
+
+ if (cf.can_id & CAN_ERR_FLAG) {
+ struct can_frame *err_cf;
+ struct sk_buff *skb = alloc_can_err_skb(ndev, &err_cf);
+
+ if (unlikely(!skb))
+ return -ENOMEM;
+
+ err_cf->can_id |= cf.can_id;
+ memcpy(err_cf->data, cf.data, CAN_MAX_DLEN);
+
+ netif_rx(skb);
+
+ return -EREMOTEIO;
+ }
+
+ return 0;
+}
+
+int lin_rx(struct lin_device *ldev, const struct lin_frame *lf)
+{
+ struct net_device *ndev = ldev->ndev;
+ struct can_frame *cf;
+ struct sk_buff *skb;
+ int ret;
+
+ if (ldev->can.state == CAN_STATE_STOPPED)
+ return 0;
+
+ netdev_dbg(ndev, "id:%02x, len:%u, data:%*ph, checksum:%02x (%s)\n",
+ lf->lin_id, lf->len, lf->len, lf->data, lf->checksum,
+ lf->checksum_mode ? "enhanced" : "classic");
+
+ ret = lin_bump_rx_err(ldev, lf);
+ if (ret) {
+ DEV_STATS_INC(ndev, rx_dropped);
+ return ret;
+ }
+
+ skb = alloc_can_skb(ndev, &cf);
+ if (unlikely(!skb)) {
+ DEV_STATS_INC(ndev, rx_dropped);
+ return -ENOMEM;
+ }
+
+ cf->can_id = lf->lin_id;
+ cf->len = min(lf->len, LIN_MAX_DLEN);
+ memcpy(cf->data, lf->data, cf->len);
+
+ DEV_STATS_INC(ndev, rx_packets);
+ DEV_STATS_ADD(ndev, rx_bytes, cf->len);
+
+ netif_receive_skb(skb);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(lin_rx);
+
+static int lin_set_bittiming(struct net_device *ndev)
+{
+ struct lin_device *ldev = netdev_priv(ndev);
+ unsigned int bitrate = ldev->can.bittiming.bitrate;
+
+ return ldev->ldev_ops->update_bitrate(ldev, bitrate);
+}
+
+static const u32 lin_bitrate[] = { 1200, 2400, 4800, 9600, 19200 };
+
+struct lin_device *register_lin(struct device *dev,
+ const struct lin_device_ops *ldops)
+{
+ struct net_device *ndev;
+ struct lin_device *ldev;
+ int ret;
+
+ if (!ldops || !ldops->ldo_tx || !ldops->update_bitrate ||
+ !ldops->ldo_open || !ldops->ldo_stop) {
+ netdev_err(ndev, "missing mandatory lin_device_ops\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ ndev = alloc_candev(sizeof(struct lin_device), 1);
+ if (!ndev)
+ return ERR_PTR(-ENOMEM);
+
+ ldev = netdev_priv(ndev);
+
+ ldev->ldev_ops = ldops;
+ ndev->netdev_ops = &lin_netdev_ops;
+ ndev->flags |= IFF_ECHO;
+ ndev->mtu = CANFD_MTU;
+ ldev->can.bittiming.bitrate = LIN_DEFAULT_BAUDRATE;
+ ldev->can.ctrlmode = CAN_CTRLMODE_LIN;
+ ldev->can.ctrlmode_supported = 0;
+ ldev->can.bitrate_const = lin_bitrate;
+ ldev->can.bitrate_const_cnt = ARRAY_SIZE(lin_bitrate);
+ ldev->can.do_set_bittiming = lin_set_bittiming;
+ ldev->ndev = ndev;
+ ldev->dev = dev;
+
+ SET_NETDEV_DEV(ndev, dev);
+
+ ret = lin_set_bittiming(ndev);
+ if (ret) {
+ netdev_err(ndev, "set bittiming failed\n");
+ goto exit_candev;
+ }
+
+ ret = register_candev(ndev);
+ if (ret)
+ goto exit_candev;
+
+ ldev->lin_ids_kobj = kobject_create_and_add("lin_ids", &ndev->dev.kobj);
+ if (!ldev->lin_ids_kobj) {
+ netdev_err(ndev, "Failed to create sysfs directory\n");
+ ret = -ENOMEM;
+ goto exit_unreg;
+ }
+
+ ret = lin_create_sysfs_id_files(ndev);
+ if (ret) {
+ netdev_err(ndev, "Failed to create sysfs entry: %d\n", ret);
+ goto exit_kobj_put;
+ }
+
+ /* Using workqueue as tx over USB/SPI/... may sleep */
+ ldev->wq = alloc_workqueue(dev_name(dev), WQ_FREEZABLE | WQ_MEM_RECLAIM,
+ 0);
+ if (!ldev->wq)
+ goto exit_rm_files;
+
+ INIT_WORK(&ldev->tx_work, lin_tx_work_handler);
+
+ netdev_info(ndev, "LIN initialized.\n");
+
+ return ldev;
+
+exit_rm_files:
+ lin_remove_sysfs_id_files(ndev);
+exit_kobj_put:
+ kobject_put(ldev->lin_ids_kobj);
+exit_unreg:
+ unregister_candev(ndev);
+exit_candev:
+ free_candev(ndev);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(register_lin);
+
+void unregister_lin(struct lin_device *ldev)
+{
+ struct net_device *ndev = ldev->ndev;
+
+ lin_remove_sysfs_id_files(ndev);
+ kobject_put(ldev->lin_ids_kobj);
+ unregister_candev(ndev);
+ destroy_workqueue(ldev->wq);
+ free_candev(ndev);
+}
+EXPORT_SYMBOL_GPL(unregister_lin);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Christoph Fritz <christoph.fritz@hexdev.de>");
+MODULE_DESCRIPTION("LIN bus to CAN glue driver");
new file mode 100644
@@ -0,0 +1,91 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/* Copyright (C) 2024 hexDEV GmbH - https://hexdev.de */
+
+#ifndef _NET_LIN_H_
+#define _NET_LIN_H_
+
+#include <linux/bitfield.h>
+#include <linux/can/dev.h>
+#include <linux/device.h>
+
+#define LIN_NUM_IDS 64
+#define LIN_HEADER_SIZE 3
+#define LIN_MAX_DLEN 8
+
+#define LIN_MAX_BAUDRATE 20000
+#define LIN_MIN_BAUDRATE 1000
+#define LIN_DEFAULT_BAUDRATE 9600
+#define LIN_SYNC_BYTE 0x55
+
+#define LIN_ID_MASK GENMASK(5, 0)
+/* special ID descriptions for LIN */
+#define LIN_ENHANCED_CKSUM_FLAG 0x00000100U
+
+extern u8 lin_get_id_parity(u8 id);
+
+#define LIN_GET_ID(PID) FIELD_GET(LIN_ID_MASK, PID)
+#define LIN_FORM_PID(ID) (LIN_GET_ID(ID) | \
+ lin_get_id_parity(LIN_GET_ID(ID)))
+#define LIN_GET_PARITY(PID) ((PID) & ~LIN_ID_MASK)
+#define LIN_CHECK_PID(PID) (LIN_GET_PARITY(PID) == \
+ LIN_GET_PARITY(LIN_FORM_PID(PID)))
+
+struct lin_attr {
+ struct kobj_attribute attr;
+ struct lin_device *ldev;
+};
+
+struct lin_device {
+ struct can_priv can; /* must be the first member */
+ struct net_device *ndev;
+ struct device *dev;
+ const struct lin_device_ops *ldev_ops;
+ struct workqueue_struct *wq;
+ struct work_struct tx_work;
+ bool tx_busy;
+ struct sk_buff *tx_skb;
+ struct kobject *lin_ids_kobj;
+ struct lin_attr sysfs_entries[LIN_NUM_IDS];
+};
+
+enum lin_checksum_mode {
+ LINBUS_CLASSIC = 0,
+ LINBUS_ENHANCED,
+};
+
+struct lin_frame {
+ u8 lin_id;
+ u8 len;
+ u8 data[LIN_MAX_DLEN];
+ u8 checksum;
+ enum lin_checksum_mode checksum_mode;
+};
+
+struct lin_responder_answer {
+ bool is_active;
+ bool is_event_frame;
+ u8 event_associated_id;
+ struct lin_frame lf;
+};
+
+struct lin_device_ops {
+ int (*ldo_open)(struct lin_device *ldev);
+ int (*ldo_stop)(struct lin_device *ldev);
+ int (*ldo_tx)(struct lin_device *ldev, const struct lin_frame *frame);
+ int (*update_bitrate)(struct lin_device *ldev, u16 bitrate);
+ int (*update_responder_answer)(struct lin_device *ldev,
+ const struct lin_responder_answer *answ);
+ int (*get_responder_answer)(struct lin_device *ldev, u8 id,
+ struct lin_responder_answer *answ);
+};
+
+int lin_rx(struct lin_device *ldev, const struct lin_frame *lf);
+
+u8 lin_get_checksum(u8 pid, u8 n_of_bytes, const u8 *bytes,
+ enum lin_checksum_mode cm);
+
+struct lin_device *register_lin(struct device *dev,
+ const struct lin_device_ops *ldops);
+void unregister_lin(struct lin_device *ldev);
+
+#endif /* _NET_LIN_H_ */
@@ -103,6 +103,7 @@ struct can_ctrlmode {
#define CAN_CTRLMODE_CC_LEN8_DLC 0x100 /* Classic CAN DLC option */
#define CAN_CTRLMODE_TDC_AUTO 0x200 /* CAN transiver automatically calculates TDCV */
#define CAN_CTRLMODE_TDC_MANUAL 0x400 /* TDCV is manually set up by user */
+#define CAN_CTRLMODE_LIN 0x800 /* LIN bus mode */
/*
* CAN device statistics