sllin: Small corrections to Slave mode.

[linux-lin.git] / sllin / sllin.c

diff --git a/sllin/sllin.c b/sllin/sllin.c
index 528d746c077eb101fe1945494947727dc566d232..671ba1adbada475c784d61f169a062a5298dac9f 100644 (file)
--- a/sllin/sllin.c
+++ b/sllin/sllin.c
@@ -1,4 +1,4 @@
-/*
+/* 
  * sllin.c - serial line LIN interface driver (using tty line discipline)
  *
  * This file is derived from drivers/net/can/slcan.c
@@ -32,8 +32,13 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
  * DAMAGE.
  *
- * Send feedback to <socketcan-users@lists.berlios.de>
- *
+ * Idea:       Oliver Hartkopp <oliver.hartkopp@volkswagen.de> 
+ * Copyright:  (c) 2011 Czech Technical University in Prague
+ *             (c) 2011 Volkswagen Group Research
+ * Authors:    Pavel Pisa <pisa@cmp.felk.cvut.cz>
+ *             Rostislav Lisovy <lisovy@kormus.cz>
+ *             Michal Sojka <sojkam1@fel.cvut.cz>
+ * Funded by:  Volkswagen Group Research
  */
 
 #define DEBUG          1 /* Enables pr_debug() printouts */
@@ -70,11 +75,19 @@ static __initdata const char banner[] =
 MODULE_ALIAS_LDISC(N_SLLIN);
 MODULE_DESCRIPTION("serial line LIN interface");
 MODULE_LICENSE("GPL");
-MODULE_AUTHOR("");
+MODULE_AUTHOR("Pavel Pisa <pisa@cmp.felk.cvut.cz>");
 
 #define SLLIN_MAGIC            0x53CA
 /* #define BREAK_BY_BAUD */
 
+static int master = true;
+static int baudrate = 0; /* Use LIN_DEFAULT_BAUDRATE when not set */
+
+module_param(master, bool, 0);
+MODULE_PARM_DESC(master, "LIN interface is Master device");
+module_param(baudrate, int, 0);
+MODULE_PARM_DESC(baudrate, "Baudrate of LIN interface");
+
 static int maxdev = 10;                /* MAX number of SLLIN channels;
                                   This can be overridden with
                                   insmod sllin.ko maxdev=nnn   */
@@ -133,6 +146,8 @@ struct sllin {
        char                    id_to_send;     /* there is ID to be sent */
        char                    data_to_send;   /* there are data to be sent */
        char                    resp_len_known; /* Length of the response is known */
+       char                    header_received;/* In Slave mode, set when header was already
+                                                  received */
 
        unsigned long           flags;          /* Flag values/ mode etc     */
 #define SLF_INUSE              0               /* Channel in use            */
@@ -250,6 +265,12 @@ static void sll_bump(struct sllin *sl)
                sl->rx_cnt - SLLIN_BUFF_DATA - 1); /* without checksum */
 }
 
+static void sll_send_rtr(struct sllin *sl)
+{
+       sllin_send_canfr(sl, (sl->rx_buff[SLLIN_BUFF_ID] & LIN_ID_MASK) |
+               CAN_RTR_FLAG, NULL, 0);
+}
+
 /*
  * Called by the driver when there's room for more data.  If we have
  * more packets to send, we send them here.
@@ -412,7 +433,7 @@ static void sllin_receive_buf(struct tty_struct *tty,
 {
        struct sllin *sl = (struct sllin *) tty->disc_data;
 
-       pr_debug("sllin: sllin_receive_buf invoked\n");
+       pr_debug("sllin: sllin_receive_buf invoked, count = %u\n", count);
 
        if (!sl || sl->magic != SLLIN_MAGIC || !netif_running(sl->dev))
                return;
@@ -430,6 +451,11 @@ static void sllin_receive_buf(struct tty_struct *tty,
                                if (sl->lin_master == true) {
                                        wake_up(&sl->kwt_wq);
                                        return;
+                               } else {
+                                       sl->rx_cnt = 0;
+                                       sl->rx_expect = SLLIN_BUFF_ID + 1;
+                                       sl->header_received = false;
+                                       return;
                                }
 
                                cp++;
@@ -439,8 +465,9 @@ static void sllin_receive_buf(struct tty_struct *tty,
 
                if (sl->rx_cnt < SLLIN_BUFF_LEN) {
 #ifndef BREAK_BY_BAUD
-                       /* We didn't receive Break character */
+                       /* We didn't receive Break character -- fake it! */
                        if ((sl->rx_cnt == SLLIN_BUFF_BREAK) && (*cp == 0x55)) {
+                               pr_debug("sllin: LIN_RX[%d]: 0x00\n", sl->rx_cnt);
                                sl->rx_buff[sl->rx_cnt++] = 0x00;
                        }
 #endif
@@ -449,12 +476,45 @@ 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);
-       } else {
-               pr_debug("sllin: sllin_receive_buf count %d, waiting\n", sl->rx_cnt);
+       if (sl->lin_master == true) {
+               if (sl->rx_cnt >= sl->rx_expect) { /* Probably whole frame was received */
+                       set_bit(SLF_RXEVENT, &sl->flags);
+                       wake_up(&sl->kwt_wq);
+                       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);
+               }
+       } else { /* LIN slave */
+               int lin_id;
+               struct sllin_conf_entry *sce;
+
+               /* Received whole header */
+               if ((sl->rx_cnt >= (SLLIN_BUFF_ID + 1)) &&
+                       (sl->header_received == false))
+               {
+                       lin_id = sl->rx_buff[SLLIN_BUFF_ID] & LIN_ID_MASK;
+                       sce = &sl->linfr_cache[lin_id];
+
+                       /* Is the length of data set in frame cache? */
+                       if (sce->frame_fl & LIN_LOC_SLAVE_CACHE)
+                               sl->rx_expect += sce->dlc;
+                       else
+                               sl->rx_expect += 2; /* 1 data byte + checksum */
+
+                       sl->header_received = true;
+                       sll_send_rtr(sl);
+               }
+
+               /* Probably whole frame was received */
+               if ((sl->rx_cnt >= sl->rx_expect) && (sl->rx_cnt > SLLIN_BUFF_DATA)) {
+                       sll_bump(sl);
+                       pr_debug("sllin: Received LIN header & LIN response. "
+                               "rx_cnt = %u, rx_expect = %u\n", sl->rx_cnt,
+                               sl->rx_expect);
+                       sl->rx_cnt = 0;
+                       sl->rx_expect = SLLIN_BUFF_ID + 1;
+                       sl->header_received = false;
+               }
        }
 }
 
@@ -475,7 +535,7 @@ void sllin_report_error(struct sllin *sl, int err)
                        sl->dev->stats.rx_crc_errors++;
                        break;
 
-               case LIN_ERR_RX_TIMEOUT:                
+               case LIN_ERR_RX_TIMEOUT:
                        sl->dev->stats.rx_errors++;
                        break;
 
@@ -1116,11 +1176,18 @@ static int sllin_open(struct tty_struct *tty)
 
        if (!test_bit(SLF_INUSE, &sl->flags)) {
                /* Perform the low-level SLLIN initialization. */
-               sl->lin_master = true;
+               sl->lin_master = master;
+#ifdef DEBUG
+               if (master)
+                       pr_debug("sllin: Configured as MASTER\n");
+               else
+                       pr_debug("sllin: Configured as SLAVE\n");
+#endif
 
                sllin_reset_buffs(sl);
 
-               sl->lin_baud  = 19200;
+               sl->lin_baud = (baudrate == 0) ? LIN_DEFAULT_BAUDRATE : baudrate;
+               pr_debug("sllin: Baudrate set to %u\n", sl->lin_baud);
 
                sl->lin_state = SLSTATE_IDLE;