]> rtime.felk.cvut.cz Git - linux-lin.git/blobdiff - sllin/sllin.c
sllin: General purpose LIN-related flags and masks moved into separate header file.
[linux-lin.git] / sllin / sllin.c
index bee3e173346804e2e3a7515c25e364649582a3af..d1821e801ab4969f697feb750aa68541f5bdcf75 100644 (file)
@@ -36,6 +36,8 @@
  *
  */
 
+#define DEBUG          1 /* Enables pr_debug() printouts */
+
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 
 #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[] =
        KERN_INFO "sllin: serial line LIN interface driver\n";
@@ -68,8 +72,8 @@ MODULE_DESCRIPTION("serial line LIN interface");
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("");
 
-#define SLLIN_MAGIC 0x53CA
-// #define BREAK_BY_BAUD
+#define SLLIN_MAGIC            0x53CA
+/* #define BREAK_BY_BAUD */
 
 static int maxdev = 10;                /* MAX number of SLLIN channels;
                                   This can be overridden with
@@ -78,17 +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_STATUS_FLAG SLLIN_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
 
 enum slstate {
        SLSTATE_IDLE = 0,
@@ -103,20 +106,6 @@ 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 particualr 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_ERR_RX_TIMEOUT    (1 << (SLLIN_CANFR_FLAGS_OFFS + 6))
-#define SLLIN_ERR_CHECKSUM      (1 << (SLLIN_CANFR_FLAGS_OFFS + 7))
-//#define SLLIN_ERR_FRAMING     (1 << (SLLIN_CANFR_FLAGS_OFFS + 8))
-
        canid_t frame_fl;       /* LIN frame flags. Passed from userspace as canid_t data type */
        u8 data[8];             /* LIN frame data payload */
 };
@@ -154,7 +143,7 @@ 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
@@ -165,18 +154,30 @@ struct sllin {
 };
 
 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;
@@ -231,11 +232,16 @@ static void sllin_send_canfr(struct sllin *sl, canid_t id, char *data, int len)
 
 }
 
+/**
+ * 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,
                sl->rx_buff + SLLIN_BUFF_DATA,
-               sl->rx_cnt - SLLIN_BUFF_DATA);
+               sl->rx_cnt - SLLIN_BUFF_DATA - 1); /* without checksum */
 }
 
 /*
@@ -262,7 +268,7 @@ static void sllin_write_wakeup(struct tty_struct *tty)
                sl->tx_cnt += actual;
 
                if (sl->tx_cnt < sl->tx_lim) {
-                       printk(KERN_INFO "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;
                }
@@ -272,26 +278,36 @@ static void sllin_write_wakeup(struct tty_struct *tty)
        set_bit(SLF_TXEVENT, &sl->flags);
        wake_up(&sl->kwt_wq);
 
-       printk(KERN_INFO "sllin_write_wakeup sent %d, wakeup\n", sl->tx_cnt);
+       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);
+       struct can_frame *cf;
 
        if (skb->len != sizeof(struct can_frame))
                goto err_out;
 
        spin_lock(&sl->lock);
        if (!netif_running(dev))  {
-               spin_unlock(&sl->lock);
                printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name);
-               goto err_out;
+               goto err_out_unlock;
        }
        if (sl->tty == NULL) {
-               spin_unlock(&sl->lock);
-               goto err_out;
+               goto err_out_unlock;
+       }
+
+       cf = (struct can_frame *) skb->data;
+       if (cf->can_id & SLLIN_CTRL_FRAME) {
+               sllin_configure_frame_cache(sl, cf);
+               goto free_out_unlock;
        }
 
        netif_stop_queue(sl->dev);
@@ -302,6 +318,9 @@ static netdev_tx_t sll_xmit(struct sk_buff *skb, struct net_device *dev)
        spin_unlock(&sl->lock);
        return NETDEV_TX_OK;
 
+free_out_unlock:
+err_out_unlock:
+       spin_unlock(&sl->lock);
 err_out:
        kfree_skb(skb);
        return NETDEV_TX_OK;
@@ -380,21 +399,12 @@ 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)
 {
        struct sllin *sl = (struct sllin *) tty->disc_data;
 
-       printk(KERN_INFO "sllin_receive_buf invoked\n");
+       pr_debug("sllin: sllin_receive_buf invoked\n");
 
        if (!sl || sl->magic != SLLIN_MAGIC || !netif_running(sl->dev))
                return;
@@ -404,7 +414,7 @@ static void sllin_receive_buf(struct tty_struct *tty,
                if (fp && *fp++) {
                        if (!test_and_set_bit(SLF_ERROR, &sl->flags))
                                sl->dev->stats.rx_errors++;
-                       printk(KERN_INFO "sllin_receive_buf char 0x%02x ignored "
+                       pr_debug("sllin: sllin_receive_buf char 0x%02x ignored "
                                "due marker 0x%02x, flags 0x%lx\n",
                                *cp, *(fp-1), sl->flags);
                        cp++;
@@ -418,7 +428,7 @@ static void sllin_receive_buf(struct tty_struct *tty,
                                sl->rx_buff[sl->rx_cnt++] = 0x00;
                        }
 #endif
-                       printk(KERN_INFO "LIN_RX[%d]: 0x%02x\n", sl->rx_cnt, *cp);
+                       pr_debug("sllin: LIN_RX[%d]: 0x%02x\n", sl->rx_cnt, *cp);
                        sl->rx_buff[sl->rx_cnt++] = *cp++;
                }
        }
@@ -426,41 +436,87 @@ 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);
-               printk(KERN_INFO "sllin_receive_buf count %d, wakeup\n", sl->rx_cnt);
+               pr_debug("sllin: sllin_receive_buf count %d, wakeup\n", sl->rx_cnt);
        } else {
-               printk(KERN_INFO "sllin_receive_buf count %d, waiting\n", sl->rx_cnt);
+               pr_debug("sllin: sllin_receive_buf count %d, waiting\n", sl->rx_cnt);
        }
 }
 
 /*****************************************
  *  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);
 }
 
-int sllin_configure_frame_cache(struct sllin *sl, struct can_frame *cf)
+/**
+ * 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))
                return -1;
 
        sce = &sl->linfr_cache[cf->can_id & SLLIN_ID_MASK];
-       printk(KERN_INFO "Setting frame cache with EFF CAN frame. "
+       pr_debug("sllin: Setting frame cache with EFF CAN frame. "
                "LIN ID = %d\n", cf->can_id & SLLIN_ID_MASK);
 
-       sce->dlc = (cf->can_dlc > 8) ? 8 : cf->can_dlc;
+       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;
        memcpy(sce->data, cf->data, cf->can_dlc);
 
        return 0;
 }
 
-#define SLLIN_STPMSG_RESPONLY  (1) /* Message will be LIN Response only */
-#define SLLIN_STPMSG_CHCKSUMV1 (1 << 1)
-#define SLLIN_STPMSG_CHCKSUMV2 (1 << 2)
+/**
+ * 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;
+       int i;
+
+       if (enhanced_fl) {
+               i = SLLIN_BUFF_ID;
+       } else {
+               i = SLLIN_BUFF_DATA;
+       }
+       
+       for (; i < length; i++) {
+               csum += data[i];
+               if (csum > 255)
+                       csum -= 255;
+       }
+
+       return ~csum & 0xff;
+}
+
+#define SLLIN_STPMSG_RESPONLY          (1) /* Message will be LIN Response only */
+#define SLLIN_STPMSG_CHCKSUM_CLS       (1 << 1)
+#define SLLIN_STPMSG_CHCKSUM_ENH       (1 << 2)
 
 int sllin_setup_msg(struct sllin *sl, int mode, int id,
                unsigned char *data, int len)
@@ -481,19 +537,10 @@ int sllin_setup_msg(struct sllin *sl, int mode, int id,
        sl->tx_lim = SLLIN_BUFF_DATA;
 
        if ((data != NULL) && len) {
-               int i;
-               unsigned csum = 0;
-
                sl->tx_lim += len;
                memcpy(sl->tx_buff + SLLIN_BUFF_DATA, data, len);
-               /* compute data parity there */
-               for (i = SLLIN_BUFF_DATA; i < sl->tx_lim; i++) {
-                       csum += sl->tx_buff[i];
-                       if (csum > 255)
-                               csum -= 255;
-               }
-
-               sl->tx_buff[sl->tx_lim++] = csum;
+               sl->tx_buff[sl->tx_lim++] = sllin_checksum(sl->tx_buff,
+                               sl->tx_lim, mode & SLLIN_STPMSG_CHCKSUM_ENH);
        }
        if (len != 0)
                sl->rx_lim = SLLIN_BUFF_DATA + len + 1;
@@ -536,7 +583,7 @@ int sllin_send_tx_buff(struct sllin *sl)
                sl->tx_cnt += res;
        }
 
-       printk(KERN_INFO "sllin_send_tx_buff sent %d, remains %d\n",
+       pr_debug("sllin: sllin_send_tx_buff sent %d, remains %d\n",
                        sl->tx_cnt, remains);
 
        return 0;
@@ -571,10 +618,12 @@ int sllin_send_break(struct sllin *sl)
 int sllin_send_break(struct sllin *sl)
 {
        struct tty_struct *tty = sl->tty;
-       unsigned long break_baud;
-       unsigned long flags;    
        int retval;
+       unsigned long break_baud;
+       unsigned long usleep_range_min;
+       unsigned long usleep_range_max;
 
+       break_baud = ((sl->lin_baud * 2) / 3);
        sl->rx_cnt = SLLIN_BUFF_BREAK;
        sl->rx_expect = SLLIN_BUFF_BREAK + 1;
        sl->lin_state = SLSTATE_BREAK_SENT;
@@ -586,16 +635,20 @@ int sllin_send_break(struct sllin *sl)
                return retval;
 
        //udelay(712);
-       usleep_range(650, 750);
+       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);
 
        retval = tty->ops->break_ctl(tty, 0);
-       usleep_range(50, 100);
+       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;
 
-       printk(KERN_INFO "sllin: Break sent.\n");
+       pr_debug("sllin: Break sent.\n");
        set_bit(SLF_RXEVENT, &sl->flags);
        wake_up(&sl->kwt_wq);
 
@@ -615,6 +668,40 @@ static enum hrtimer_restart sllin_rx_timeout_handler(struct hrtimer *hrtimer)
        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;   
+
+       actual_id = sl->rx_buff[SLLIN_BUFF_ID] & SLLIN_ID_MASK; 
+       scf = &sl->linfr_cache[actual_id];
+       lin_dlc = scf->dlc;
+       ext_chcks_fl = scf->frame_fl & SLLIN_CHECKSUM_EXTENDED;
+
+       if (sllin_checksum(sl->rx_buff, sl->rx_cnt - 1, ext_chcks_fl) != 
+               rec_chcksm) {
+
+               /* Type of checksum is configured for particular frame */
+               if (lin_dlc > 0) {
+                       return -1;
+               } else {
+                       if (sllin_checksum(sl->rx_buff, sl->rx_cnt - 1,
+                               !ext_chcks_fl) != rec_chcksm) {
+                               return -1;
+                       }
+               }
+       }
+
+       return 0;
+}
 
 /*****************************************
  *  sllin_kwthread - kernel worker thread
@@ -625,20 +712,22 @@ int sllin_kwthread(void *ptr)
        struct sllin *sl = (struct sllin *)ptr;
        struct tty_struct *tty = sl->tty;
        struct sched_param schparam = { .sched_priority = 40 };
-       int res;
-       struct can_frame *cf;
-       u8 *lin_data;
-       int lin_dlc;
        int tx_bytes = 0; /* Used for Network statistics */
 
 
-       printk(KERN_INFO "sllin: sllin_kwthread started.\n");
+       pr_debug("sllin: sllin_kwthread started.\n");
        sched_setscheduler(current, SCHED_FIFO, &schparam);
 
        clear_bit(SLF_ERROR, &sl->flags);
        sltty_change_speed(tty, sl->lin_baud);
 
        while (!kthread_should_stop()) {
+               struct can_frame *cf;
+               u8 *lin_data;
+               int lin_dlc;
+               u8 lin_data_buff[SLLIN_DATA_MAX];
+
+
                if ((sl->lin_state == SLSTATE_IDLE) && sl->lin_master &&
                        sl->id_to_send) {
                        if(sllin_send_break(sl) < 0) {
@@ -655,15 +744,15 @@ int sllin_kwthread(void *ptr)
                                && test_bit(SLF_MSGEVENT, &sl->flags)));
 
                if (test_and_clear_bit(SLF_RXEVENT, &sl->flags)) {
-                       printk(KERN_INFO "sllin_kthread RXEVENT \n");
+                       pr_debug("sllin: sllin_kthread RXEVENT \n");
                }
 
                if (test_and_clear_bit(SLF_TXEVENT, &sl->flags)) {
-                       printk(KERN_INFO "sllin_kthread TXEVENT \n");
+                       pr_debug("sllin: sllin_kthread TXEVENT \n");
                }
 
                if (test_and_clear_bit(SLF_TMOUTEVENT, &sl->flags)) {
-                       printk(KERN_INFO "sllin_kthread TMOUTEVENT \n");
+                       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;
@@ -675,55 +764,62 @@ int sllin_kwthread(void *ptr)
                        sl->lin_state = SLSTATE_IDLE;
                }
 
-               if ((sl->lin_state == SLSTATE_IDLE) && test_bit(SLF_MSGEVENT, &sl->flags)) {
-                       cf = (struct can_frame *)sl->tx_req_skb->data;
-
-                       /* EFF CAN frame -> "Configuration" frame */
-                       if (cf->can_id & CAN_EFF_FLAG) {
-                               sllin_configure_frame_cache(sl, cf);
-                               goto free_skb;
-                       } /* SFF RTR CAN frame -> LIN header */ 
-                       else if (cf->can_id & CAN_RTR_FLAG) {
-                               printk(KERN_INFO "%s: RTR SFF CAN frame, ID = %x\n",
-                                       __FUNCTION__, cf->can_id & SLLIN_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)) {
-                                       
-                                       printk(KERN_INFO "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;
-                               } else {
-                                       lin_data = NULL;
-                                       lin_dlc = sl->linfr_cache[cf->can_id & SLLIN_ID_MASK].dlc;
+               switch (sl->lin_state) {
+                       case SLSTATE_IDLE:
+                               if (!test_bit(SLF_MSGEVENT, &sl->flags))
+                                       break;
+
+                               cf = (struct can_frame *)sl->tx_req_skb->data;
+
+                               /* 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);
+
+                                       /* 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)) {
+                                               
+                                               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;
+                                               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;
+                                       }
+                                       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);
+
+                                       lin_data = cf->data;
+                                       lin_dlc = cf->can_dlc;
+                                       if (lin_dlc > SLLIN_DATA_MAX)
+                                               lin_dlc = SLLIN_DATA_MAX;
+                                       tx_bytes = lin_dlc;
                                }
-                       } else { /* SFF NON-RTR CAN frame -> LIN header + LIN response */
-                               printk(KERN_INFO "%s: NON-RTR SFF CAN frame, ID = %x\n",
-                                       __FUNCTION__, (int)cf->can_id & SLLIN_ID_MASK);
-
-                               lin_data = cf->data;
-                               lin_dlc = tx_bytes = cf->can_dlc;
-                       }
 
-                       if (sllin_setup_msg(sl, 0, cf->can_id & SLLIN_ID_MASK,
-                               lin_data, lin_dlc) != -1) {
+                               if (sllin_setup_msg(sl, 0, cf->can_id & SLLIN_ID_MASK,
+                                       lin_data, lin_dlc) != -1) {
 
-                               sl->id_to_send = true;
-                               sl->data_to_send = (lin_data != NULL) ? true : false;
-                               sl->resp_len_known = (lin_dlc > 0) ? true : false;
-                               sl->dev->stats.tx_packets++;
-                               sl->dev->stats.tx_bytes += tx_bytes;
-                       }
+                                       sl->id_to_send = true;
+                                       sl->data_to_send = (lin_data != NULL) ? true : false;
+                                       sl->resp_len_known = (lin_dlc > 0) ? true : false;
+                                       sl->dev->stats.tx_packets++;
+                                       sl->dev->stats.tx_bytes += tx_bytes;
+                               }
 
-               free_skb:
-                       clear_bit(SLF_MSGEVENT, &sl->flags);
-                       kfree_skb(sl->tx_req_skb);
-                       netif_wake_queue(sl->dev);
-               }
+                               clear_bit(SLF_MSGEVENT, &sl->flags);
+                               kfree_skb(sl->tx_req_skb);
+                               netif_wake_queue(sl->dev);
+                               break;
 
-               switch (sl->lin_state) {
                        case SLSTATE_BREAK_SENT:
 #ifdef BREAK_BY_BAUD
                                if (sl->rx_cnt <= SLLIN_BUFF_BREAK)
@@ -761,43 +857,34 @@ int sllin_kwthread(void *ptr)
                        case SLSTATE_RESPONSE_WAIT:
                        slstate_response_wait:
                                if (test_bit(SLF_MSGEVENT, &sl->flags)) {
+                                       unsigned char *lin_buff;
                                        cf = (struct can_frame *)sl->tx_req_skb->data;
 
-                                       /* EFF CAN frame -> "Configuration" frame */
-                                       if (cf->can_id & CAN_EFF_FLAG) {
-                                               sllin_configure_frame_cache(sl, cf);
+                                       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,
+                                                       cf->data, cf->can_dlc) != -1) {
 
-                                               clear_bit(SLF_MSGEVENT, &sl->flags);
-                                               kfree_skb(sl->tx_req_skb);
-                                               netif_wake_queue(sl->dev);
-                                       } else {
-                                               unsigned char *lin_buff;
-                                               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,
-                                                               cf->data, cf->can_dlc) != -1) {
-
-                                                               sl->rx_expect = sl->tx_lim;
-                                                               sl->data_to_send = true;
-                                                               sl->dev->stats.tx_packets++;
-                                                               sl->dev->stats.tx_bytes += tx_bytes;
-
-                                                               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);
-                                                               netif_wake_queue(sl->dev);
-
-                                                               sl->lin_state = SLSTATE_RESPONSE_SENT;
-                                                               goto slstate_response_sent;
+                                                       sl->rx_expect = sl->tx_lim;
+                                                       sl->data_to_send = true;
+                                                       sl->dev->stats.tx_packets++;
+                                                       sl->dev->stats.tx_bytes += tx_bytes;
+
+                                                       if (!sl->lin_master) {
+                                                               sl->tx_cnt = SLLIN_BUFF_DATA;
                                                        }
-                                               } else {
-                                                       sl->lin_state = SLSTATE_RESPONSE_WAIT_BUS;
+                                                       
+                                                       sllin_send_tx_buff(sl);
+                                                       clear_bit(SLF_MSGEVENT, &sl->flags);
+                                                       kfree_skb(sl->tx_req_skb);
+                                                       netif_wake_queue(sl->dev);
+
+                                                       sl->lin_state = SLSTATE_RESPONSE_SENT;
+                                                       goto slstate_response_sent;
                                                }
+                                       } else {
+                                               sl->lin_state = SLSTATE_RESPONSE_WAIT_BUS;
                                        }
                                }
 
@@ -806,13 +893,20 @@ int sllin_kwthread(void *ptr)
                                        continue;
                        
                                hrtimer_cancel(&sl->rx_timer);
-                               printk(KERN_INFO "sllin: response received ID %d len %d\n",
+                               pr_debug("sllin: response received ID %d len %d\n",
                                        sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
-                               // FIXME: check checksum in sl->rx_buff
 
-                               // send CAN non-RTR frame with data
-                               printk(KERN_INFO "sllin: sending NON-RTR CAN frame with LIN payload.");
-                               sll_bump(sl); //send packet to the network layer
+                               if (sllin_rx_validate(sl) == -1) {
+                                       pr_debug("sllin: RX validation failed.\n");
+                                       sllin_report_error(sl, SLLIN_ERR_CHECKSUM);
+                                       //FIXME tx_stat.err++
+                               } else {
+                                       // 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
+                               }
+
                                sl->id_to_send = false;
                                sl->lin_state = SLSTATE_IDLE;
                                break;
@@ -823,7 +917,7 @@ int sllin_kwthread(void *ptr)
                                        continue;
                                
                                sll_bump(sl); //send packet to the network layer
-                               printk(KERN_INFO "sllin: response sent ID %d len %d\n",
+                               pr_debug("sllin: response sent ID %d len %d\n",
                                        sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
 
                                sl->id_to_send = false;
@@ -839,7 +933,7 @@ int sllin_kwthread(void *ptr)
        }
 
        hrtimer_cancel(&sl->rx_timer);
-       printk(KERN_INFO "sllin: sllin_kwthread stopped.\n");
+       pr_debug("sllin: sllin_kwthread stopped.\n");
 
        return 0;
 }
@@ -983,14 +1077,12 @@ static int sllin_open(struct tty_struct *tty)
 
                sl->lin_state = SLSTATE_IDLE;
 
-#define SAMPLES_PER_CHAR       10
-#define CHARS_TO_TIMEOUT       12
                hrtimer_init(&sl->rx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
                sl->rx_timer.function = sllin_rx_timeout_handler;
                /* timeval_to_ktime(msg_head->ival1); */
                sl->rx_timer_timeout = ns_to_ktime(
-                       (1000000000 / sl->lin_baud) * 
-                       SAMPLES_PER_CHAR * CHARS_TO_TIMEOUT); 
+                       (1000000000l / sl->lin_baud) * 
+                       SLLIN_SAMPLES_PER_CHAR * SLLIN_CHARS_TO_TIMEOUT); 
  
                set_bit(SLF_INUSE, &sl->flags);
 
@@ -1106,7 +1198,7 @@ static int __init sllin_init(void)
                maxdev = 4; /* Sanity */
 
        printk(banner);
-       printk(KERN_INFO "sllin: %d dynamic interface channels.\n", maxdev);
+       pr_debug("sllin: %d dynamic interface channels.\n", maxdev);
 
        sllin_devs = kzalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL);
        if (!sllin_devs) {
@@ -1120,6 +1212,13 @@ static int __init sllin_init(void)
                printk(KERN_ERR "sllin: can't register line discipline\n");
                kfree(sllin_devs);
        }
+
+#ifdef BREAK_BY_BAUD
+       pr_debug("sllin: Break is generated by baud-rate change.");
+#else
+       pr_debug("sllin: Break is generated manually with tiny sleep.");
+#endif
+
        return status;
 }