]> rtime.felk.cvut.cz Git - linux-lin.git/blobdiff - sllin/sllin.c
sllin: Improved handling of UART errors.
[linux-lin.git] / sllin / sllin.c
index 750d48966491e574fda44a4a68f56daee5689d2f..528d746c077eb101fe1945494947727dc566d232 100644 (file)
 #include <linux/can.h>
 #include <linux/kthread.h>
 #include <linux/hrtimer.h>
+#include "linux/lin_bus.h"
 
 /* Should be in include/linux/tty.h */
-#define N_SLLIN         25
+#define N_SLLIN                25
 /* -------------------------------- */
 
 static __initdata const char banner[] =
@@ -71,7 +72,7 @@ MODULE_DESCRIPTION("serial line LIN interface");
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("");
 
-#define SLLIN_MAGIC 0x53CA
+#define SLLIN_MAGIC            0x53CA
 /* #define BREAK_BY_BAUD */
 
 static int maxdev = 10;                /* MAX number of SLLIN channels;
@@ -81,20 +82,16 @@ module_param(maxdev, int, 0);
 MODULE_PARM_DESC(maxdev, "Maximum number of sllin interfaces");
 
 /* maximum buffer len to store whole LIN message*/
-#define SLLIN_DATA_MAX  8
-#define SLLIN_BUFF_LEN (1 /*break*/ + 1 /*sync*/ + 1 /*ID*/ + \
-                         SLLIN_DATA_MAX + 1 /*checksum*/)
-#define SLLIN_BUFF_BREAK 0
-#define SLLIN_BUFF_SYNC         1
-#define SLLIN_BUFF_ID   2
-#define SLLIN_BUFF_DATA         3
-
-#define SLLIN_ID_MASK          0x3f
-#define SLLIN_ID_MAX           SLLIN_ID_MASK
-#define SLLIN_CTRL_FRAME       CAN_EFF_FLAG
+#define SLLIN_DATA_MAX         8
+#define SLLIN_BUFF_LEN         (1 /*break*/ + 1 /*sync*/ + 1 /*ID*/ + \
+                               SLLIN_DATA_MAX + 1 /*checksum*/)
+#define SLLIN_BUFF_BREAK       0
+#define SLLIN_BUFF_SYNC                1
+#define SLLIN_BUFF_ID          2
+#define SLLIN_BUFF_DATA                3
 
 #define SLLIN_SAMPLES_PER_CHAR 10
-#define SLLIN_CHARS_TO_TIMEOUT 12
+#define SLLIN_CHARS_TO_TIMEOUT 24
 
 enum slstate {
        SLSTATE_IDLE = 0,
@@ -109,22 +106,8 @@ enum slstate {
 
 struct sllin_conf_entry {
        int dlc;                /* Length of data in LIN frame */
-#define SLLIN_CANFR_FLAGS_OFFS 6 /* Lower 6 bits in can_id correspond to LIN ID */
-/* Save configuration for particular LIN ID */
-#define SLLIN_LIN_ID_CONF      (1 <<  SLLIN_CANFR_FLAGS_OFFS)
-/* Publisher of particular LIN response is SLLIN Master */
-#define SLLIN_SRC_MASTER       (1 << (SLLIN_CANFR_FLAGS_OFFS + 1))
-#define SLLIN_SRC_SLAVE                (1 << (SLLIN_CANFR_FLAGS_OFFS + 2))
-#define SLLIN_SLAVE_LOCAL      (1 << (SLLIN_CANFR_FLAGS_OFFS + 3))
-#define SLLIN_SLAVE_REMOTE     (1 << (SLLIN_CANFR_FLAGS_OFFS + 4))
-#define SLLIN_LOC_SLAVE_CACHE  (1 << (SLLIN_CANFR_FLAGS_OFFS + 5))
-#define SLLIN_CHECKSUM_EXTENDED        (1 << (SLLIN_CANFR_FLAGS_OFFS + 6))
-
-#define SLLIN_ERR_RX_TIMEOUT    (1 << (SLLIN_CANFR_FLAGS_OFFS + 7))
-#define SLLIN_ERR_CHECKSUM      (1 << (SLLIN_CANFR_FLAGS_OFFS + 8))
-//#define SLLIN_ERR_FRAMING     (1 << (SLLIN_CANFR_FLAGS_OFFS + 9))
-
-       canid_t frame_fl;       /* LIN frame flags. Passed from userspace as canid_t data type */
+       canid_t frame_fl;       /* LIN frame flags. Passed from userspace as
+                                  canid_t data type */
        u8 data[8];             /* LIN frame data payload */
 };
 
@@ -161,31 +144,42 @@ struct sllin {
 
        dev_t                   line;
        struct task_struct      *kwthread;
-       wait_queue_head_t       kwt_wq;
+       wait_queue_head_t       kwt_wq;         /* Wait queue used by kwthread */
        struct hrtimer          rx_timer;       /* RX timeout timer */
        ktime_t                 rx_timer_timeout; /* RX timeout timer value */
-       struct sk_buff          *tx_req_skb;    /* Socket buffer with CAN frame received
-                                               from network stack*/
+       struct sk_buff          *tx_req_skb;    /* Socket buffer with CAN frame
+                                               received from network stack*/
 
-       struct sllin_conf_entry linfr_cache[SLLIN_ID_MAX + 1]; /* List with configurations for
-                                               each of 0 to SLLIN_ID_MAX LIN IDs */
+       /* List with configurations for each of 0 to LIN_ID_MAX LIN IDs */
+       struct sllin_conf_entry linfr_cache[LIN_ID_MAX + 1];
 };
 
 static struct net_device **sllin_devs;
 static int sllin_configure_frame_cache(struct sllin *sl, struct can_frame *cf);
 
 
+/* Values of two parity bits in LIN Protected
+   Identifier for each particular LIN ID */
 const unsigned char sllin_id_parity_table[] = {
-        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
+        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
 };
 
+/**
+ * sltty_change_speed() -- Change baudrate of Serial device belonging
+ *                        to particular @tty
+ *
+ * @tty:       Pointer to TTY to change speed for.
+ * @speed:     Integer value of new speed. It is possible to
+ *             assign non-standard values, i.e. those which
+ *             are not defined in termbits.h.
+ */
 static int sltty_change_speed(struct tty_struct *tty, unsigned speed)
 {
        struct ktermios old_termios;
@@ -194,10 +188,16 @@ static int sltty_change_speed(struct tty_struct *tty, unsigned speed)
        mutex_lock(&tty->termios_mutex);
 
        old_termios = *(tty->termios);
-       cflag = tty->termios->c_cflag;
+
+       cflag = CS8 | CREAD | CLOCAL | HUPCL;
        cflag &= ~(CBAUD | CIBAUD);
        cflag |= BOTHER;
        tty->termios->c_cflag = cflag;
+       tty->termios->c_oflag = 0;
+       tty->termios->c_lflag = 0;
+
+       /* Enable interrupt when UART-Break or Framing error received */
+       tty->termios->c_iflag = BRKINT | INPCK;
 
        tty_encode_baud_rate(tty, speed, speed);
 
@@ -209,7 +209,6 @@ static int sltty_change_speed(struct tty_struct *tty, unsigned speed)
        return 0;
 }
 
-
 /* Send one can_frame to the network layer */
 static void sllin_send_canfr(struct sllin *sl, canid_t id, char *data, int len)
 {
@@ -236,13 +235,17 @@ static void sllin_send_canfr(struct sllin *sl, canid_t id, char *data, int len)
 
        sl->dev->stats.rx_packets++;
        sl->dev->stats.rx_bytes += cf.can_dlc;
-
-
 }
 
+/**
+ * sll_bump() -- Send data of received LIN frame (existing in sl->rx_buff)
+ *              as CAN frame
+ *
+ * @sl:
+ */
 static void sll_bump(struct sllin *sl)
 {
-       sllin_send_canfr(sl, sl->rx_buff[SLLIN_BUFF_ID] & SLLIN_ID_MASK,
+       sllin_send_canfr(sl, sl->rx_buff[SLLIN_BUFF_ID] & LIN_ID_MASK,
                sl->rx_buff + SLLIN_BUFF_DATA,
                sl->rx_cnt - SLLIN_BUFF_DATA - 1); /* without checksum */
 }
@@ -267,11 +270,13 @@ static void sllin_write_wakeup(struct tty_struct *tty)
                remains = SLLIN_BUFF_BREAK + 1 - sl->tx_cnt;
 
        if (remains > 0) {
-               actual = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, sl->tx_cnt - sl->tx_lim);
+               actual = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt,
+                       sl->tx_cnt - sl->tx_lim);
                sl->tx_cnt += actual;
 
                if (sl->tx_cnt < sl->tx_lim) {
-                       pr_debug("sllin: sllin_write_wakeup sent %d, remains %d, waiting\n",
+                       pr_debug("sllin: sllin_write_wakeup sent %d, "
+                               "remains %d, waiting\n",
                                sl->tx_cnt, sl->tx_lim - sl->tx_cnt);
                        return;
                }
@@ -284,7 +289,12 @@ static void sllin_write_wakeup(struct tty_struct *tty)
        pr_debug("sllin: sllin_write_wakeup sent %d, wakeup\n", sl->tx_cnt);
 }
 
-/* Send a can_frame to a TTY queue. */
+/**
+ * sll_xmit() -- Send a can_frame to a TTY queue.
+ *
+ * @skb: Pointer to Socket buffer to be sent.
+ * @dev: Network device where @skb will be sent.
+ */
 static netdev_tx_t sll_xmit(struct sk_buff *skb, struct net_device *dev)
 {
        struct sllin *sl = netdev_priv(dev);
@@ -303,7 +313,7 @@ static netdev_tx_t sll_xmit(struct sk_buff *skb, struct net_device *dev)
        }
 
        cf = (struct can_frame *) skb->data;
-       if (cf->can_id & SLLIN_CTRL_FRAME) {
+       if (cf->can_id & LIN_CTRL_FRAME) {
                sllin_configure_frame_cache(sl, cf);
                goto free_out_unlock;
        }
@@ -397,15 +407,6 @@ static void sll_setup(struct net_device *dev)
   Routines looking at TTY side.
  ******************************************/
 
-/*
- * Handle the 'receiver data ready' interrupt.
- * This function is called by the 'tty_io' module in the kernel when
- * a block of SLLIN data has been received, which can now be decapsulated
- * and sent on to some IP layer for further processing. This will not
- * be re-entered while running but other ldisc functions may be called
- * in parallel
- */
-
 static void sllin_receive_buf(struct tty_struct *tty,
                              const unsigned char *cp, char *fp, int count)
 {
@@ -419,13 +420,21 @@ static void sllin_receive_buf(struct tty_struct *tty,
        /* Read the characters out of the buffer */
        while (count--) {
                if (fp && *fp++) {
-                       if (!test_and_set_bit(SLF_ERROR, &sl->flags))
-                               sl->dev->stats.rx_errors++;
-                       pr_debug("sllin: sllin_receive_buf char 0x%02x ignored "
-                               "due marker 0x%02x, flags 0x%lx\n",
-                               *cp, *(fp-1), sl->flags);
-                       cp++;
-                       continue;
+                       if (sl->rx_cnt > SLLIN_BUFF_BREAK) {
+                               set_bit(SLF_ERROR, &sl->flags);
+
+                               pr_debug("sllin: sllin_receive_buf char 0x%02x ignored "
+                                       "due marker 0x%02x, flags 0x%lx\n",
+                                       *cp, *(fp-1), sl->flags);
+
+                               if (sl->lin_master == true) {
+                                       wake_up(&sl->kwt_wq);
+                                       return;
+                               }
+
+                               cp++;
+                               continue;
+                       }
                }
 
                if (sl->rx_cnt < SLLIN_BUFF_LEN) {
@@ -443,7 +452,7 @@ static void sllin_receive_buf(struct tty_struct *tty,
        if (sl->rx_cnt >= sl->rx_expect) {
                set_bit(SLF_RXEVENT, &sl->flags);
                wake_up(&sl->kwt_wq);
-               pr_debug("sllin: sllin_receive_buf count %d, wakeup\n", sl->rx_cnt);
+               pr_debug("sllin: sllin_receive_buf count %d, wakeup\n", sl->rx_cnt);
        } else {
                pr_debug("sllin: sllin_receive_buf count %d, waiting\n", sl->rx_cnt);
        }
@@ -452,32 +461,69 @@ static void sllin_receive_buf(struct tty_struct *tty,
 /*****************************************
  *  sllin message helper routines
  *****************************************/
+/**
+ * sllin_report_error() -- Report an error by sending CAN frame
+ *     with particular error flag set in can_id
+ *
+ * @sl:
+ * @err: Error flag to be sent.
+ */
 void sllin_report_error(struct sllin *sl, int err)
 {
-       sllin_send_canfr(sl, 0 | CAN_EFF_FLAG | 
-               (err & ~SLLIN_ID_MASK), NULL, 0);
+       switch (err) {
+               case LIN_ERR_CHECKSUM:
+                       sl->dev->stats.rx_crc_errors++;
+                       break;
+
+               case LIN_ERR_RX_TIMEOUT:                
+                       sl->dev->stats.rx_errors++;
+                       break;
+
+               case LIN_ERR_FRAMING:
+                       sl->dev->stats.rx_frame_errors++;
+                       break;
+       }
+
+       sllin_send_canfr(sl, 0 | CAN_EFF_FLAG |
+               (err & ~LIN_ID_MASK), NULL, 0);
 }
 
+/**
+ * sllin_configure_frame_cache() -- Configure particular entry in linfr_cache
+ *
+ * @sl:
+ * @cf: Pointer to CAN frame sent to this driver
+ *     holding configuration information
+ */
 static int sllin_configure_frame_cache(struct sllin *sl, struct can_frame *cf)
 {
        struct sllin_conf_entry *sce;
-       if (!(cf->can_id & SLLIN_LIN_ID_CONF))
+       if (!(cf->can_id & LIN_ID_CONF))
                return -1;
 
-       sce = &sl->linfr_cache[cf->can_id & SLLIN_ID_MASK];
+       sce = &sl->linfr_cache[cf->can_id & LIN_ID_MASK];
        pr_debug("sllin: Setting frame cache with EFF CAN frame. "
-               "LIN ID = %d\n", cf->can_id & SLLIN_ID_MASK);
+               "LIN ID = %d\n", cf->can_id & LIN_ID_MASK);
 
        sce->dlc = cf->can_dlc;
        if (sce->dlc > SLLIN_DATA_MAX)
                sce->dlc = SLLIN_DATA_MAX;
 
-       sce->frame_fl = (cf->can_id & ~SLLIN_ID_MASK) & CAN_EFF_MASK;
+       sce->frame_fl = (cf->can_id & ~LIN_ID_MASK) & CAN_EFF_MASK;
        memcpy(sce->data, cf->data, cf->can_dlc);
 
        return 0;
 }
 
+/**
+ * sllin_checksum() -- Count checksum for particular data
+ *
+ * @data:       Pointer to the buffer containing whole LIN
+ *              frame (i.e. including break and sync bytes).
+ * @length:     Length of the buffer.
+ * @enhanced_fl: Flag determining whether Enhanced or Classic
+ *              checksum should be counted.
+ */
 static inline unsigned sllin_checksum(unsigned char *data, int length, int enhanced_fl)
 {
        unsigned csum = 0;
@@ -488,7 +534,7 @@ static inline unsigned sllin_checksum(unsigned char *data, int length, int enhan
        } else {
                i = SLLIN_BUFF_DATA;
        }
-       
+
        for (; i < length; i++) {
                csum += data[i];
                if (csum > 255)
@@ -505,7 +551,7 @@ static inline unsigned sllin_checksum(unsigned char *data, int length, int enhan
 int sllin_setup_msg(struct sllin *sl, int mode, int id,
                unsigned char *data, int len)
 {
-       if (id > SLLIN_ID_MASK)
+       if (id > LIN_ID_MASK)
                return -1;
 
        if (!(mode & SLLIN_STPMSG_RESPONLY)) {
@@ -532,6 +578,16 @@ int sllin_setup_msg(struct sllin *sl, int mode, int id,
        return 0;
 }
 
+static void sllin_reset_buffs(struct sllin *sl)
+{
+       sl->rx_cnt = 0;
+       sl->rx_expect = 0;
+       sl->rx_lim = sl->lin_master ? 0 : SLLIN_BUFF_LEN;
+       sl->tx_cnt = 0;
+       sl->tx_lim = 0;
+       sl->id_to_send = false;
+       sl->data_to_send = false;
+}
 
 int sllin_send_tx_buff(struct sllin *sl)
 {
@@ -562,7 +618,7 @@ int sllin_send_tx_buff(struct sllin *sl)
                        clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
                        return -1;
                }
-               
+
                remains -= res;
                sl->tx_cnt += res;
        }
@@ -612,13 +668,13 @@ int sllin_send_break(struct sllin *sl)
        sl->rx_expect = SLLIN_BUFF_BREAK + 1;
        sl->lin_state = SLSTATE_BREAK_SENT;
 
-       /* Do the break ourselves; Inspired by 
+       /* Do the break ourselves; Inspired by
           http://lxr.linux.no/#linux+v3.1.2/drivers/tty/tty_io.c#L2452 */
        retval = tty->ops->break_ctl(tty, -1);
        if (retval)
                return retval;
 
-       //udelay(712);
+       /* udelay(712); */
        usleep_range_min = (1000000l * SLLIN_SAMPLES_PER_CHAR) / break_baud;
        usleep_range_max = usleep_range_min + 50;
        usleep_range(usleep_range_min, usleep_range_max);
@@ -627,7 +683,7 @@ int sllin_send_break(struct sllin *sl)
        usleep_range_min = (1000000l * 1 /* 1 bit */) / break_baud;
        usleep_range_max = usleep_range_min + 30;
        usleep_range(usleep_range_min, usleep_range_max);
-       
+
        tty->ops->flush_buffer(tty);
 
        sl->tx_cnt = SLLIN_BUFF_SYNC;
@@ -645,27 +701,32 @@ static enum hrtimer_restart sllin_rx_timeout_handler(struct hrtimer *hrtimer)
 {
        struct sllin *sl = container_of(hrtimer, struct sllin, rx_timer);
 
-       sllin_report_error(sl, SLLIN_ERR_RX_TIMEOUT);
+       sllin_report_error(sl, LIN_ERR_RX_TIMEOUT);
        set_bit(SLF_TMOUTEVENT, &sl->flags);
        wake_up(&sl->kwt_wq);
 
        return HRTIMER_NORESTART;
 }
 
+/**
+ * sllin_rx_validate() -- Validate received frame, i,e. check checksum
+ *
+ * @sl:
+ */
 static int sllin_rx_validate(struct sllin *sl)
 {
        int actual_id;
        int ext_chcks_fl;
        int lin_dlc;
        unsigned char rec_chcksm = sl->rx_buff[sl->rx_cnt - 1];
-       struct sllin_conf_entry *scf;   
+       struct sllin_conf_entry *scf;
 
-       actual_id = sl->rx_buff[SLLIN_BUFF_ID] & SLLIN_ID_MASK; 
+       actual_id = sl->rx_buff[SLLIN_BUFF_ID] & LIN_ID_MASK;
        scf = &sl->linfr_cache[actual_id];
        lin_dlc = scf->dlc;
-       ext_chcks_fl = scf->frame_fl & SLLIN_CHECKSUM_EXTENDED;
+       ext_chcks_fl = scf->frame_fl & LIN_CHECKSUM_EXTENDED;
 
-       if (sllin_checksum(sl->rx_buff, sl->rx_cnt - 1, ext_chcks_fl) != 
+       if (sllin_checksum(sl->rx_buff, sl->rx_cnt - 1, ext_chcks_fl) !=
                rec_chcksm) {
 
                /* Type of checksum is configured for particular frame */
@@ -718,28 +779,40 @@ int sllin_kwthread(void *ptr)
                        test_bit(SLF_RXEVENT, &sl->flags) ||
                        test_bit(SLF_TXEVENT, &sl->flags) ||
                        test_bit(SLF_TMOUTEVENT, &sl->flags) ||
-                       (((sl->lin_state == SLSTATE_IDLE) || 
-                               (sl->lin_state == SLSTATE_RESPONSE_WAIT)) 
+                       test_bit(SLF_ERROR, &sl->flags) ||
+                       (((sl->lin_state == SLSTATE_IDLE) ||
+                               (sl->lin_state == SLSTATE_RESPONSE_WAIT))
                                && test_bit(SLF_MSGEVENT, &sl->flags)));
 
                if (test_and_clear_bit(SLF_RXEVENT, &sl->flags)) {
-                       pr_debug("sllin: sllin_kthread RXEVENT \n");
+                       pr_debug("sllin: sllin_kthread RXEVENT\n");
+               }
+
+               if (test_and_clear_bit(SLF_ERROR, &sl->flags)) {
+                       unsigned long usleep_range_min;
+                       unsigned long usleep_range_max;
+                       hrtimer_cancel(&sl->rx_timer);
+                       pr_debug("sllin: sllin_kthread ERROR\n");
+
+                       if (sl->lin_state != SLSTATE_IDLE)
+                               sllin_report_error(sl, LIN_ERR_FRAMING);
+
+                       usleep_range_min = (1000000l * SLLIN_SAMPLES_PER_CHAR * 10) /
+                                               sl->lin_baud;
+                       usleep_range_max = usleep_range_min + 50;
+                       usleep_range(usleep_range_min, usleep_range_max);
+                       sllin_reset_buffs(sl);
+                       sl->lin_state = SLSTATE_IDLE;
                }
 
                if (test_and_clear_bit(SLF_TXEVENT, &sl->flags)) {
-                       pr_debug("sllin: sllin_kthread TXEVENT \n");
+                       pr_debug("sllin: sllin_kthread TXEVENT\n");
                }
 
                if (test_and_clear_bit(SLF_TMOUTEVENT, &sl->flags)) {
-                       pr_debug("sllin: sllin_kthread TMOUTEVENT \n");
-                       sl->rx_cnt = 0;
-                       sl->rx_expect = 0;
-                       sl->rx_lim = sl->lin_master ? 0 : SLLIN_BUFF_LEN;
-                       sl->tx_cnt = 0;
-                       sl->tx_lim = 0;
-                       sl->id_to_send = false;
-                       sl->data_to_send = false;
-                       
+                       pr_debug("sllin: sllin_kthread TMOUTEVENT\n");
+                       sllin_reset_buffs(sl);
+
                        sl->lin_state = SLSTATE_IDLE;
                }
 
@@ -750,32 +823,32 @@ int sllin_kwthread(void *ptr)
 
                                cf = (struct can_frame *)sl->tx_req_skb->data;
 
-                               /* SFF RTR CAN frame -> LIN header */ 
+                               /* SFF RTR CAN frame -> LIN header */
                                if (cf->can_id & CAN_RTR_FLAG) {
                                        spin_lock(&sl->lock);
                                        pr_debug("sllin: %s: RTR SFF CAN frame, ID = %x\n",
-                                               __FUNCTION__, cf->can_id & SLLIN_ID_MASK);
+                                               __FUNCTION__, cf->can_id & LIN_ID_MASK);
 
                                        /* Is there Slave response in linfr_cache to be sent? */
-                                       if ((sl->linfr_cache[cf->can_id & SLLIN_ID_MASK].frame_fl & 
-                                               SLLIN_LOC_SLAVE_CACHE) 
-                                               && (sl->linfr_cache[cf->can_id & SLLIN_ID_MASK].dlc > 0)) {
-                                               
+                                       if ((sl->linfr_cache[cf->can_id & LIN_ID_MASK].frame_fl &
+                                               LIN_LOC_SLAVE_CACHE)
+                                               && (sl->linfr_cache[cf->can_id & LIN_ID_MASK].dlc > 0)) {
+
                                                pr_debug("sllin: Sending LIN response from linfr_cache\n");
-                                               lin_data = sl->linfr_cache[cf->can_id & SLLIN_ID_MASK].data;
-                                               lin_dlc = sl->linfr_cache[cf->can_id & SLLIN_ID_MASK].dlc;
+                                               lin_data = sl->linfr_cache[cf->can_id & LIN_ID_MASK].data;
+                                               lin_dlc = sl->linfr_cache[cf->can_id & LIN_ID_MASK].dlc;
                                                if (lin_dlc > SLLIN_DATA_MAX)
                                                        lin_dlc = SLLIN_DATA_MAX;
                                                memcpy(lin_data_buff, lin_data, lin_dlc);
                                                lin_data = lin_data_buff;
                                        } else {
                                                lin_data = NULL;
-                                               lin_dlc = sl->linfr_cache[cf->can_id & SLLIN_ID_MASK].dlc;
+                                               lin_dlc = sl->linfr_cache[cf->can_id & LIN_ID_MASK].dlc;
                                        }
                                        spin_unlock(&sl->lock);
                                } else { /* SFF NON-RTR CAN frame -> LIN header + LIN response */
                                        pr_debug("sllin: %s: NON-RTR SFF CAN frame, ID = %x\n",
-                                               __FUNCTION__, (int)cf->can_id & SLLIN_ID_MASK);
+                                               __FUNCTION__, (int)cf->can_id & LIN_ID_MASK);
 
                                        lin_data = cf->data;
                                        lin_dlc = cf->can_dlc;
@@ -784,7 +857,7 @@ int sllin_kwthread(void *ptr)
                                        tx_bytes = lin_dlc;
                                }
 
-                               if (sllin_setup_msg(sl, 0, cf->can_id & SLLIN_ID_MASK,
+                               if (sllin_setup_msg(sl, 0, cf->can_id & LIN_ID_MASK,
                                        lin_data, lin_dlc) != -1) {
 
                                        sl->id_to_send = true;
@@ -797,6 +870,9 @@ int sllin_kwthread(void *ptr)
                                clear_bit(SLF_MSGEVENT, &sl->flags);
                                kfree_skb(sl->tx_req_skb);
                                netif_wake_queue(sl->dev);
+                               hrtimer_start(&sl->rx_timer,
+                                       ktime_add(ktime_get(), sl->rx_timer_timeout),
+                                       HRTIMER_MODE_ABS);
                                break;
 
                        case SLSTATE_BREAK_SENT:
@@ -812,6 +888,7 @@ int sllin_kwthread(void *ptr)
                                break;
 
                        case SLSTATE_ID_SENT:
+                               hrtimer_cancel(&sl->rx_timer);
                                sl->id_to_send = false;
                                if (sl->data_to_send) {
                                        sllin_send_tx_buff(sl);
@@ -826,7 +903,7 @@ int sllin_kwthread(void *ptr)
                                        }
                                        sl->lin_state = SLSTATE_RESPONSE_WAIT;
                                        /* If we don't receive anything, timer will "unblock" us */
-                                       hrtimer_start(&sl->rx_timer, 
+                                       hrtimer_start(&sl->rx_timer,
                                                ktime_add(ktime_get(), sl->rx_timer_timeout),
                                                HRTIMER_MODE_ABS);
                                        goto slstate_response_wait;
@@ -840,9 +917,11 @@ int sllin_kwthread(void *ptr)
                                        cf = (struct can_frame *)sl->tx_req_skb->data;
 
                                        lin_buff = (sl->lin_master) ? sl->tx_buff : sl->rx_buff;
-                                       if (cf->can_id == (lin_buff[SLLIN_BUFF_ID] & SLLIN_ID_MASK)) {
-                                               if (sllin_setup_msg(sl, SLLIN_STPMSG_RESPONLY, 
-                                                       cf->can_id & SLLIN_ID_MASK,
+                                       if (cf->can_id == (lin_buff[SLLIN_BUFF_ID] & LIN_ID_MASK)) {
+                                               hrtimer_cancel(&sl->rx_timer);
+                                               pr_debug("sllin: received LIN response in a CAN frame.\n");
+                                               if (sllin_setup_msg(sl, SLLIN_STPMSG_RESPONLY,
+                                                       cf->can_id & LIN_ID_MASK,
                                                        cf->data, cf->can_dlc) != -1) {
 
                                                        sl->rx_expect = sl->tx_lim;
@@ -853,7 +932,7 @@ int sllin_kwthread(void *ptr)
                                                        if (!sl->lin_master) {
                                                                sl->tx_cnt = SLLIN_BUFF_DATA;
                                                        }
-                                                       
+
                                                        sllin_send_tx_buff(sl);
                                                        clear_bit(SLF_MSGEVENT, &sl->flags);
                                                        kfree_skb(sl->tx_req_skb);
@@ -867,35 +946,36 @@ int sllin_kwthread(void *ptr)
                                        }
                                }
 
+                               /* Be aware, no BREAK here */
                        case SLSTATE_RESPONSE_WAIT_BUS:
                                if (sl->rx_cnt < sl->rx_expect)
                                        continue;
-                       
+
                                hrtimer_cancel(&sl->rx_timer);
                                pr_debug("sllin: response received ID %d len %d\n",
                                        sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
 
                                if (sllin_rx_validate(sl) == -1) {
                                        pr_debug("sllin: RX validation failed.\n");
-                                       sllin_report_error(sl, SLLIN_ERR_CHECKSUM);
-                                       //FIXME tx_stat.err++
+                                       sllin_report_error(sl, LIN_ERR_CHECKSUM);
                                } else {
-                                       // send CAN non-RTR frame with data
+                                       /* Send CAN non-RTR frame with data */
                                        pr_debug("sllin: sending NON-RTR CAN"
                                                "frame with LIN payload.");
-                                       sll_bump(sl); //send packet to the network layer
+                                       sll_bump(sl); /* send packet to the network layer */
                                }
 
                                sl->id_to_send = false;
                                sl->lin_state = SLSTATE_IDLE;
                                break;
-                       
+
                        case SLSTATE_RESPONSE_SENT:
                        slstate_response_sent:
                                if (sl->rx_cnt < sl->tx_lim)
                                        continue;
-                               
-                               sll_bump(sl); //send packet to the network layer
+
+                               hrtimer_cancel(&sl->rx_timer);
+                               sll_bump(sl); /* send packet to the network layer */
                                pr_debug("sllin: response sent ID %d len %d\n",
                                        sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
 
@@ -903,12 +983,6 @@ int sllin_kwthread(void *ptr)
                                sl->lin_state = SLSTATE_IDLE;
                                break;
                }
-
-
-
-
-               /* sl->dev->stats.tx_packets++; send frames statistic */
-               /* netif_wake_queue(sl->dev); allow next Tx packet arrival */
        }
 
        hrtimer_cancel(&sl->rx_timer);
@@ -1044,13 +1118,7 @@ static int sllin_open(struct tty_struct *tty)
                /* Perform the low-level SLLIN initialization. */
                sl->lin_master = true;
 
-               sl->rx_cnt = 0;
-               sl->rx_expect = 0;
-               sl->rx_lim = sl->lin_master ? 0 : SLLIN_BUFF_LEN;
-               sl->tx_cnt = 0;
-               sl->tx_lim = 0;
-               sl->id_to_send = false;
-               sl->data_to_send = false;
+               sllin_reset_buffs(sl);
 
                sl->lin_baud  = 19200;
 
@@ -1060,9 +1128,9 @@ static int sllin_open(struct tty_struct *tty)
                sl->rx_timer.function = sllin_rx_timeout_handler;
                /* timeval_to_ktime(msg_head->ival1); */
                sl->rx_timer_timeout = ns_to_ktime(
-                       (1000000000l / sl->lin_baud) * 
-                       SLLIN_SAMPLES_PER_CHAR * SLLIN_CHARS_TO_TIMEOUT); 
+                       (1000000000l / sl->lin_baud) *
+                       SLLIN_SAMPLES_PER_CHAR * SLLIN_CHARS_TO_TIMEOUT);
+
                set_bit(SLF_INUSE, &sl->flags);
 
                init_waitqueue_head(&sl->kwt_wq);
@@ -1077,7 +1145,7 @@ static int sllin_open(struct tty_struct *tty)
 
        /* Done.  We have linked the TTY line to a channel. */
        rtnl_unlock();
-       tty->receive_room = SLLIN_BUFF_LEN * 40;        /* We don't flow control */
+       tty->receive_room = SLLIN_BUFF_LEN * 40; /* We don't flow control */
 
        /* TTY layer expects 0 on success */
        return 0;