On Mon, 2024-05-06 at 20:03 +0300, Ilpo Järvinen wrote: > On Thu, 2 May 2024, Christoph Fritz wrote: > > > This commit introduces LIN-Bus support for UART devices equipped with > > LIN transceivers, utilizing the Serial Device Bus (serdev) interface. > > > > For more details on an adapter, visit: https://hexdev.de/hexlin#tty > > > > Signed-off-by: Christoph Fritz <christoph.fritz@xxxxxxxxx> > > --- > > drivers/net/can/Kconfig | 16 ++ > > drivers/net/can/Makefile | 1 + > > drivers/net/can/lin-serdev.c | 500 +++++++++++++++++++++++++++++++++++ > > 3 files changed, 517 insertions(+) > > create mode 100644 drivers/net/can/lin-serdev.c > > > > diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig > > index 0934bbf8d03b2..91c6cdeefe440 100644 > > --- a/drivers/net/can/Kconfig > > +++ b/drivers/net/can/Kconfig > > @@ -181,6 +181,22 @@ config CAN_LIN > > > > Actual device drivers need to be enabled too. > > > > +config CAN_LIN_SERDEV > > + tristate "Serial LIN Adaptors" > > + depends on CAN_LIN && SERIAL_DEV_BUS && OF > > + help > > + LIN-Bus support for serial devices equipped with LIN transceievers. > > + This device driver is using CAN_LIN for a userland connection on > > + one side and the kernel its serial device bus (serdev) interface > > + on the other side. > > + > > + If you have a hexlin tty adapter, say Y here and see > > + <https://hexdev.de/hexlin#tty>. > > + > > + This driver can also be built as a module. If so, the module will be > > + called lin-serdev.ko. > > + > > + > > config CAN_SLCAN > > tristate "Serial / USB serial CAN Adaptors (slcan)" > > depends on TTY > > diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile > > index 0093ee9219ca8..21ca514a42439 100644 > > --- a/drivers/net/can/Makefile > > +++ b/drivers/net/can/Makefile > > @@ -26,6 +26,7 @@ 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-$(CONFIG_CAN_LIN_SERDEV) += lin-serdev.o > > obj-$(CONFIG_CAN_MSCAN) += mscan/ > > obj-$(CONFIG_CAN_M_CAN) += m_can/ > > obj-$(CONFIG_CAN_PEAK_PCIEFD) += peak_canfd/ > > diff --git a/drivers/net/can/lin-serdev.c b/drivers/net/can/lin-serdev.c > > new file mode 100644 > > index 0000000000000..13fd9a54c6c93 > > --- /dev/null > > +++ b/drivers/net/can/lin-serdev.c > > @@ -0,0 +1,500 @@ > > +// SPDX-License-Identifier: GPL-2.0+ > > +/* Copyright (C) 2024 hexDEV GmbH - https://hexdev.de */ > > + > > +#include <linux/delay.h> > > +#include <linux/init.h> > > +#include <linux/kfifo.h> > > +#include <linux/module.h> > > +#include <linux/of.h> > > +#include <linux/serdev.h> > > +#include <linux/slab.h> > > +#include <linux/tty.h> > > +#include <net/lin.h> > > + > > +#define LINSER_SAMPLES_PER_CHAR 10 > > +#define LINSER_TX_BUFFER_SIZE 11 > > +#define LINSER_RX_FIFO_SIZE 256 > > +#define LINSER_PARSE_BUFFER 24 > > + > > +struct linser_rx { > > + u8 data; > > + u8 flag; > > +}; > > + > > +enum linser_rx_status { > > + NEED_MORE = -1, > > + MODE_OK = 0, > > + NEED_FORCE, > > +}; > > + > > +struct linser_priv { > > + struct lin_device *lin_dev; > > + struct serdev_device *serdev; > > + DECLARE_KFIFO_PTR(rx_fifo, struct linser_rx); > > + struct delayed_work rx_work; > > + unsigned long break_usleep_min; > > + unsigned long break_usleep_max; > > + unsigned long post_break_usleep_min; > > + unsigned long post_break_usleep_max; > > + unsigned long force_timeout_jfs; > > + struct lin_responder_answer respond_answ[LIN_NUM_IDS]; > > + struct mutex resp_lock; /* protects respond_answ */ > > + bool is_stopped; > > +}; > > + > > +static int linser_open(struct lin_device *ldev) > > +{ > > + struct serdev_device *serdev = to_serdev_device(ldev->dev); > > + struct linser_priv *priv = serdev_device_get_drvdata(serdev); > > + int ret; > > + > > + if (priv->is_stopped) { > > + ret = serdev_device_open(serdev); > > + if (ret) { > > + dev_err(&serdev->dev, "Unable to open device\n"); > > + return ret; > > + } > > + > > + serdev_device_set_flow_control(serdev, false); > > + serdev_device_set_break_detection(serdev, true); > > + > > + priv->is_stopped = false; > > + } > > + > > + return 0; > > +} > > + > > +static int linser_stop(struct lin_device *ldev) > > +{ > > + struct serdev_device *serdev = to_serdev_device(ldev->dev); > > + struct linser_priv *priv = serdev_device_get_drvdata(serdev); > > + > > + if (priv->is_stopped) > > + return 0; > > + > > + serdev_device_close(serdev); > > + priv->is_stopped = true; > > + > > + return 0; > > +} > > + > > +static int linser_send_break(struct linser_priv *priv) > > +{ > > + struct serdev_device *serdev = priv->serdev; > > + int ret; > > + > > + ret = serdev_device_break_ctl(serdev, -1); > > + if (ret) > > + return ret; > > + > > + usleep_range(priv->break_usleep_min, priv->break_usleep_max); > > + > > + ret = serdev_device_break_ctl(serdev, 0); > > + if (ret) > > + return ret; > > + > > + usleep_range(priv->post_break_usleep_min, priv->post_break_usleep_max); > > + > > + return 0; > > +} > > + > > +static int linser_ldo_tx(struct lin_device *ldev, const struct lin_frame *lf) > > +{ > > + struct serdev_device *serdev = to_serdev_device(ldev->dev); > > + struct linser_priv *priv = serdev_device_get_drvdata(serdev); > > + u8 pid = LIN_FORM_PID(lf->lin_id); > > + u8 buf[LINSER_TX_BUFFER_SIZE]; > > + ssize_t written_len, total_len; > > + u8 checksum; > > + int ret; > > + > > + if (lf->len + 3 > LINSER_TX_BUFFER_SIZE) { > > + dev_err(&serdev->dev, "Frame length %u exceeds buffer size\n", lf->len); > > + return -EINVAL; > > + } > > + > > + buf[0] = LIN_SYNC_BYTE; > > + buf[1] = pid; > > + total_len = 2; > > + > > + if (lf->len) { > > + memcpy(&buf[2], lf->data, lf->len); > > + checksum = lin_get_checksum(pid, lf->len, lf->data, > > + lf->checksum_mode); > > + buf[lf->len + 2] = checksum; > > + total_len += lf->len + 1; > > + } > > + > > + ret = linser_send_break(priv); > > + if (ret) > > + return ret; > > + > > + written_len = serdev_device_write(serdev, buf, total_len, 0); > > + if (written_len < total_len) > > + return written_len < 0 ? (int)written_len : -EIO; > > + > > + dev_dbg(&serdev->dev, "sent out: %*ph\n", (int)total_len, buf); > > + > > + serdev_device_wait_until_sent(serdev, 0); > > + > > + return 0; > > +} > > + > > +static void linser_derive_timings(struct linser_priv *priv, u16 bitrate) > > +{ > > + unsigned long break_baud = (bitrate * 2) / 3; > > + unsigned long timeout_us; > > + > > + priv->break_usleep_min = (USEC_PER_SEC * LINSER_SAMPLES_PER_CHAR) / > > + break_baud; > > + priv->break_usleep_max = priv->break_usleep_min + 50; > > + priv->post_break_usleep_min = (USEC_PER_SEC * 1 /* 1 bit */) / break_baud; > > Don't mix comments and code like this. OK > > > + priv->post_break_usleep_max = priv->post_break_usleep_min + 30; > > + > > + timeout_us = DIV_ROUND_CLOSEST(USEC_PER_SEC * 256 /* bit */, bitrate); > > Ditto. OK > > > + priv->force_timeout_jfs = usecs_to_jiffies(timeout_us); > > +} > > + > > +static int linser_update_bitrate(struct lin_device *ldev, u16 bitrate) > > +{ > > + struct serdev_device *serdev = to_serdev_device(ldev->dev); > > + struct linser_priv *priv = serdev_device_get_drvdata(serdev); > > + unsigned int speed; > > + int ret; > > + > > + ret = linser_open(ldev); > > + if (ret) > > + return ret; > > + > > + speed = serdev_device_set_baudrate(serdev, bitrate); > > + if (!bitrate || speed != bitrate) > > + return -EINVAL; > > + > > + linser_derive_timings(priv, bitrate); > > + > > + return 0; > > +} > > + > > +static int linser_get_responder_answer(struct lin_device *ldev, u8 id, > > + struct lin_responder_answer *answ) > > +{ > > + struct serdev_device *serdev = to_serdev_device(ldev->dev); > > + struct linser_priv *priv = serdev_device_get_drvdata(serdev); > > + struct lin_responder_answer *r = &priv->respond_answ[id]; > > + > > + if (!answ) > > + return -EINVAL; > > + > > + mutex_lock(&priv->resp_lock); > > guard(mutex)(&priv->resp_lock); OK > > > + memcpy(answ, r, sizeof(struct lin_responder_answer)); > > sizeof(*answ); OK > > > + mutex_unlock(&priv->resp_lock); > > + > > + return 0; > > +} > > + > > +static int linser_update_resp_answer(struct lin_device *ldev, > > + const struct lin_responder_answer *answ) > > +{ > > + struct serdev_device *serdev = to_serdev_device(ldev->dev); > > + struct linser_priv *priv = serdev_device_get_drvdata(serdev); > > + struct lin_responder_answer *r = &priv->respond_answ[answ->lf.lin_id]; > > + > > + if (!answ) > > + return -EINVAL; > > + > > + mutex_lock(&priv->resp_lock); > > + memcpy(r, answ, sizeof(struct lin_responder_answer)); > > Ditto. OK > > > + r->lf.checksum = lin_get_checksum(LIN_FORM_PID(answ->lf.lin_id), > > + answ->lf.len, > > + answ->lf.data, > > + answ->lf.checksum_mode); > > + mutex_unlock(&priv->resp_lock); > > + > > + return 0; > > +} > > + > > +static struct lin_device_ops linser_lindev_ops = { > > + .ldo_open = linser_open, > > + .ldo_stop = linser_stop, > > + .ldo_tx = linser_ldo_tx, > > + .update_bitrate = linser_update_bitrate, > > + .get_responder_answer = linser_get_responder_answer, > > + .update_responder_answer = linser_update_resp_answer, > > +}; > > + > > +static bool linser_tx_frame_as_responder(struct linser_priv *priv, u8 id) > > +{ > > + struct lin_responder_answer *answ = &priv->respond_answ[id]; > > + struct serdev_device *serdev = priv->serdev; > > + u8 buf[LINSER_TX_BUFFER_SIZE]; > > + u8 checksum, count, n; > > + ssize_t write_len; > > + > > + mutex_lock(&priv->resp_lock); > > scoped_guard() can be used here. OK > > > + > > + if (!answ->is_active) { > > + mutex_unlock(&priv->resp_lock); > > + return false; > > + } > > + > > + if (answ->is_event_frame) { > > + struct lin_responder_answer *e_answ; > > + > > + e_answ = &priv->respond_answ[answ->event_associated_id]; > > + n = min(e_answ->lf.len, LIN_MAX_DLEN); > > + if (memcmp(answ->lf.data, e_answ->lf.data, n) != 0) { > > + memcpy(answ->lf.data, e_answ->lf.data, n); > > + checksum = lin_get_checksum(LIN_FORM_PID(answ->lf.lin_id), > > + n, e_answ->lf.data, > > + answ->lf.checksum_mode); > > + answ = e_answ; > > + } else { > > + mutex_unlock(&priv->resp_lock); > > + return false; > > Use reverse logic so you can reduce indent. OK > > > + } > > + } else { > > + checksum = answ->lf.checksum; > > + } > > + > > + count = min(answ->lf.len, LIN_MAX_DLEN); > > + memcpy(&buf[0], answ->lf.data, count); > > + buf[count] = checksum; > > + > > + mutex_unlock(&priv->resp_lock); > > + > > + write_len = serdev_device_write(serdev, buf, count + 1, 0); > > + if (write_len < count + 1) > > + return false; > > + > > + serdev_device_wait_until_sent(serdev, 0); > > + > > + return true; > > +} > > + > > +static void linser_pop_fifo(struct linser_priv *priv, size_t n) > > +{ > > + for (size_t i = 0; i < n; i++) > > + kfifo_skip(&priv->rx_fifo); > > +} > > + > > +static int linser_fill_frame(struct linser_priv *priv, struct lin_frame *lf) > > +{ > > + struct serdev_device *serdev = priv->serdev; > > + struct linser_rx buf[LINSER_PARSE_BUFFER]; > > + unsigned int count, i, brk = 0; > > + > > + count = kfifo_out_peek(&priv->rx_fifo, buf, LINSER_PARSE_BUFFER); > > + > > + memset(lf, 0, sizeof(struct lin_frame)); > > + > > + for (i = 0; i < count; i++) { > > + dev_dbg(&serdev->dev, "buf[%d]: data=%02x, flag=%02x\n", > > + i, buf[i].data, buf[i].flag); > > + } > > + > > + if (count < 3) > > + return NEED_MORE; > > + > > + if (buf[0].flag != TTY_BREAK || buf[1].data != LIN_SYNC_BYTE) { > > + linser_pop_fifo(priv, 1); /* pop incorrect start */ > > + return NEED_MORE; > > + } else if (!LIN_CHECK_PID(buf[2].data)) { > > + linser_pop_fifo(priv, 3); /* pop incorrect header */ > > + return NEED_MORE; > > + } > > + > > + lf->lin_id = LIN_GET_ID(buf[2].data); > > + > > + /* from here on we do have a correct LIN header */ > > + > > + if (count == 3) > > + return linser_tx_frame_as_responder(priv, lf->lin_id) ? > > + NEED_MORE : NEED_FORCE; > > + > > + for (i = 3; i < count && i < LINSER_PARSE_BUFFER && i < 12; i++) { > > + if (buf[i].flag == TTY_BREAK) { > > + brk = i; > > + break; > > + } > > + lf->len++; > > + } > > + if (lf->len) > > + lf->len -= 1; /* account for checksum */ > > + > > + if (brk == 3) > > + return MODE_OK; > > + > > + if (brk == 4) { > > + /* suppress wrong answer data-byte in between PID and break > > + * because checksum is missing > > + */ > > + return MODE_OK; > > + } > > + > > + for (i = 0; i < lf->len; i++) > > + lf->data[i] = buf[3 + i].data; > > + lf->checksum = buf[2 + lf->len + 1].data; > > + mutex_lock(&priv->resp_lock); > > + lf->checksum_mode = priv->respond_answ[lf->lin_id].lf.checksum_mode; > > + mutex_unlock(&priv->resp_lock); > > + > > + dev_dbg(&serdev->dev, "brk:%i, len:%u, data:%*ph, checksum:%x (%s)\n", > > + brk, lf->len, lf->len, lf->data, lf->checksum, > > + lf->checksum_mode ? "enhanced" : "classic"); > > + > > + if (brk > 4) > > + return MODE_OK; /* frame in between two breaks: so complete */ > > + > > + if (lf->len == 8) > > + return MODE_OK; > > + > > + return NEED_FORCE; > > +} > > + > > +static int linser_process_frame(struct linser_priv *priv, bool force) > > +{ > > + struct serdev_device *serdev = priv->serdev; > > + struct lin_frame lf; > > + size_t bytes_to_pop; > > + int ret = NEED_MORE; > > + > > + while (kfifo_len(&priv->rx_fifo) >= LIN_HEADER_SIZE) { > > + ret = linser_fill_frame(priv, &lf); > > + > > + if (ret == MODE_OK || (ret == NEED_FORCE && force)) { > > + dev_dbg(&serdev->dev, "lin_rx: %s\n", > > + force ? "force" : "normal"); > > + lin_rx(priv->lin_dev, &lf); > > + bytes_to_pop = LIN_HEADER_SIZE + lf.len + > > + (lf.len ? 1 : 0); > > + linser_pop_fifo(priv, bytes_to_pop); > > + force = false; > > + ret = MODE_OK; > > + } else { > > + return ret; > > Reverse logic & deindent the main block. OK ... thanks -- Christoph
