sllin: Improved sending of a "LIN response" sent by master following LIN header.

diff --git a/sllin/sllin.c b/sllin/sllin.c
index 636e89ac848aadbca4ecc4fbed6e3f6e94ae4262..aa4adec30811280230eff2e4f5452ae95dc4c129 100644 (file)
--- a/sllin/sllin.c
+++ b/sllin/sllin.c
@@ -108,14 +108,15 @@ struct sllin {
        unsigned char           rx_buff[SLLIN_BUFF_LEN]; /* LIN Rx buffer */
        unsigned char           tx_buff[SLLIN_BUFF_LEN]; /* LIN Tx buffer */
        int                     rx_expect;      /* expected number of Rx chars */
-       int                     rx_lim;         /* maximum Rx chars for ID  */
+       int                     rx_lim;         /* maximum Rx chars for current frame */
        int                     rx_cnt;         /* message buffer Rx fill level  */
        int                     tx_lim;         /* actual limit of bytes to Tx */
        int                     tx_cnt;         /* number of already Tx bytes */
        char                    lin_master;     /* node is a master node */
        int                     lin_baud;       /* LIN baudrate */
        int                     lin_state;      /* state */
-       int                     id_to_send;     /* there is ID to be sent */
+       char                    id_to_send;     /* there is ID to be sent */
+       char                    data_to_send;   /* there are data to be sent */
 
        unsigned long           flags;          /* Flag values/ mode etc     */
 #define SLF_INUSE              0               /* Channel in use            */
@@ -494,6 +495,7 @@ int sllin_setup_msg(struct sllin *sl, int mode, int id,
        sl->rx_cnt = 0;
        sl->tx_cnt = 0;
        sl->rx_expect = 0;
+       sl->rx_lim = SLLIN_BUFF_LEN;
 
        sl->tx_buff[SLLIN_BUFF_BREAK] = 0;
        sl->tx_buff[SLLIN_BUFF_SYNC]  = 0x55;
@@ -516,7 +518,7 @@ int sllin_setup_msg(struct sllin *sl, int mode, int id,
                sl->tx_buff[sl->tx_lim++] = csum;
        }
        if (len != 0)
-               sl->rx_lim += len + 1;
+               sl->rx_lim = SLLIN_BUFF_DATA + len + 1;
 
        return 0;
 }
@@ -675,6 +677,7 @@ int sllin_kwthread(void *ptr)
                                if (sllin_setup_msg(sl, 0, 
                                        cf->can_id & CAN_SFF_MASK, NULL, 0) != -1) {
                                        sl->id_to_send = true;
+                                       sl->data_to_send = false;
                                }
                        } else {
                                printk(KERN_INFO "%s: NON-RTR CAN frame, ID = %x\n",
@@ -683,6 +686,7 @@ int sllin_kwthread(void *ptr)
                                if (sllin_setup_msg(sl, 0, cf->can_id & CAN_SFF_MASK, 
                                        cf->data, cf->can_dlc) != -1) {
                                        sl->id_to_send = true;
+                                       sl->data_to_send = true;
                                }
                        }
 
@@ -706,6 +710,40 @@ int sllin_kwthread(void *ptr)
                                break;
 
                        case SLSTATE_ID_SENT:
+                               sl->id_to_send = false;
+                               if (sl->data_to_send) {
+                                       sllin_send_tx_buff(sl);
+                                       sl->lin_state = SLSTATE_RESPONSE_SENT;
+                                       sl->rx_expect = sl->tx_lim;
+                                       goto slstate_response_sent;
+                               } else {
+                                       sl->rx_expect = SLLIN_BUFF_DATA + 2;
+                                       sl->lin_state = SLSTATE_RESPONSE_WAIT;
+                                       goto slstate_response_wait;
+                               }
+                               break;
+
+                       case SLSTATE_RESPONSE_WAIT:
+                       slstate_response_wait:
+                               if (sl->rx_cnt < sl->rx_expect)
+                                       continue;
+                       
+                               printk(KERN_INFO "sllin: response received ID %d len %d\n",
+                                       sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
+                               // check checksum in sl->rx_buff
+                               // send CAN non-RTR frame with data
+                               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;
+                               
+                               printk(KERN_INFO "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;
                                sl->lin_state = SLSTATE_IDLE;
                                break;
@@ -851,15 +889,18 @@ static int sllin_open(struct tty_struct *tty)
 
        if (!test_bit(SLF_INUSE, &sl->flags)) {
                /* Perform the low-level SLLIN initialization. */
-               sl->rx_cnt    = 0;
+               sl->lin_master = true;
+
+               sl->rx_cnt = 0;
                sl->rx_expect = 0;
-               sl->rx_lim    = 0;
-               sl->tx_cnt    = 0;
-               sl->tx_lim    = 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;
 
                sl->lin_baud  = 19200;
 
-               sl->lin_master = 1;
                sl->lin_state = SLSTATE_IDLE;
 
                set_bit(SLF_INUSE, &sl->flags);