]> git.enpas.org Git - elmcan.git/blobdiff - module/elmcan.c
Shut down ELM327's 'protocol' before reconfiguring CAN
[elmcan.git] / module / elmcan.c
index 854ff59ba647fe7cf01b980bde1a70daa343c574..ffdb60e32c9a1a2f6084a321490fe6e4333b79d8 100644 (file)
@@ -66,6 +66,7 @@ enum ELM_TODO {
        ELM_TODO_CANID_11BIT,
        ELM_TODO_CANID_29BIT_LOW,
        ELM_TODO_CANID_29BIT_HIGH,
+       ELM_TODO_CAN_CONFIG_PART2,
        ELM_TODO_CAN_CONFIG,
        ELM_TODO_RESPONSES,
        ELM_TODO_SILENT_MONITOR,
@@ -335,8 +336,9 @@ static void elm327_feed_frame_to_netdev(struct elmcan *elm, const struct can_fra
 /* Called when we're out of ideas and just want it all to end. */
 static inline void elm327_hw_failure(struct elmcan *elm)
 {
-       struct can_frame frame = {0};
+       struct can_frame frame;
 
+       memset(&frame, 0, sizeof(frame));
        frame.can_id = CAN_ERR_FLAG;
        frame.can_dlc = CAN_ERR_DLC;
        frame.data[5] = 'R';
@@ -361,15 +363,16 @@ static inline void elm327_hw_failure(struct elmcan *elm)
 
 static void elm327_parse_error(struct elmcan *elm, int len)
 {
-       struct can_frame frame = {0};
+       struct can_frame frame;
 
+       memset(&frame, 0, sizeof(frame));
        frame.can_id = CAN_ERR_FLAG;
        frame.can_dlc = CAN_ERR_DLC;
 
        switch(len) {
                case 17:
                        if (!memcmp(elm->rxbuf, "UNABLE TO CONNECT", 17)) {
-                               pr_err("The ELM327 reported UNABLE TO CONNECT. Please check your setup.\n");
+                               netdev_err(elm->dev, "The ELM327 reported UNABLE TO CONNECT. Please check your setup.\n");
                        }
                        break;
                case 11:
@@ -404,7 +407,7 @@ static void elm327_parse_error(struct elmcan *elm, int len)
                        break;
                case 5:
                        if (!memcmp(elm->rxbuf, "ERR", 3)) {
-                               pr_err("The ELM327 reported an ERR%c%c. Please power it off and on again.\n",
+                               netdev_err(elm->dev, "The ELM327 reported an ERR%c%c. Please power it off and on again.\n",
                                        elm->rxbuf[3], elm->rxbuf[4]);
                                frame.can_id |= CAN_ERR_CRTL;
                        }
@@ -420,11 +423,13 @@ static void elm327_parse_error(struct elmcan *elm, int len)
 
 static int elm327_parse_frame(struct elmcan *elm, int len)
 {
-       struct can_frame frame = {0};
+       struct can_frame frame;
        int hexlen;
        int datastart;
        int i;
 
+       memset(&frame, 0, sizeof(frame));
+
        /* Find first non-hex and non-space character:
         *  - In the simplest case, there is none.
         *  - For RTR frames, 'R' is the first non-hex character.
@@ -563,7 +568,7 @@ static void elm327_handle_prompt(struct elmcan *elm)
 {
        if (elm->cmds_todo) {
                struct can_frame *frame = &elm->can_frame;
-               char txbuf[20];
+               char local_txbuf[20];
 
                if (test_bit(ELM_TODO_INIT, &elm->cmds_todo)) {
                        elm327_send(elm, *elm->next_init_cmd, strlen(*elm->next_init_cmd));
@@ -579,36 +584,60 @@ static void elm327_handle_prompt(struct elmcan *elm)
                         */
                        elm->state = ELM_NOTINIT;
                        elm327_kick_into_cmd_mode(elm);
+
+                       return;
+
                } else if (test_and_clear_bit(ELM_TODO_SILENT_MONITOR, &elm->cmds_todo)) {
-                       snprintf(txbuf, sizeof(txbuf), "ATCSM%i\r", !(!(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)));
+                       sprintf(local_txbuf, "ATCSM%i\r",
+                               !(!(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)));
+
                } else if (test_and_clear_bit(ELM_TODO_RESPONSES, &elm->cmds_todo)) {
-                       snprintf(txbuf, sizeof(txbuf), "ATR%i\r", !(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY));
+                       sprintf(local_txbuf, "ATR%i\r",
+                               !(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY));
+
                } else if (test_and_clear_bit(ELM_TODO_CAN_CONFIG, &elm->cmds_todo)) {
-                       snprintf(txbuf, sizeof(txbuf), "ATPB%04X\r", elm->can_config);
+                       sprintf(local_txbuf, "ATPC\r");
+                       set_bit(ELM_TODO_CAN_CONFIG_PART2, &elm->cmds_todo);
+
+               } else if (test_and_clear_bit(ELM_TODO_CAN_CONFIG_PART2, &elm->cmds_todo)) {
+                       sprintf(local_txbuf, "ATPB%04X\r",
+                               elm->can_config);
+
                } else if (test_and_clear_bit(ELM_TODO_CANID_29BIT_HIGH, &elm->cmds_todo)) {
-                       snprintf(txbuf, sizeof(txbuf), "ATCP%02X\r", (frame->can_id & CAN_EFF_MASK) >> 24);
+                       sprintf(local_txbuf, "ATCP%02X\r",
+                               (frame->can_id & CAN_EFF_MASK) >> 24);
+
                } else if (test_and_clear_bit(ELM_TODO_CANID_29BIT_LOW, &elm->cmds_todo)) {
-                       snprintf(txbuf, sizeof(txbuf), "ATSH%06X\r", frame->can_id & CAN_EFF_MASK & ((1 << 24) - 1));
+                       sprintf(local_txbuf, "ATSH%06X\r",
+                               frame->can_id & CAN_EFF_MASK & ((1 << 24) - 1));
+
                } else if (test_and_clear_bit(ELM_TODO_CANID_11BIT, &elm->cmds_todo)) {
-                       snprintf(txbuf, sizeof(txbuf), "ATSH%03X\r", frame->can_id & CAN_SFF_MASK);
+                       sprintf(local_txbuf, "ATSH%03X\r",
+                               frame->can_id & CAN_SFF_MASK);
+
                } else if (test_and_clear_bit(ELM_TODO_CAN_DATA, &elm->cmds_todo)) {
                        if (frame->can_id & CAN_RTR_FLAG) {
-                               snprintf(txbuf, sizeof(txbuf), "ATRTR\r");
+                               /* Send an RTR frame. Their DLC is fixed.
+                                * Some chips don't send them at all.
+                                */
+                               sprintf(local_txbuf, "ATRTR\r");
                        } else {
+                               /* Send a regular CAN data frame */
                                int i;
 
                                for (i = 0; i < frame->can_dlc; i++) {
-                                       sprintf(&txbuf[2*i], "%02X", frame->data[i]);
+                                       sprintf(&local_txbuf[2*i], "%02X",
+                                               frame->data[i]);
                                }
 
-                               sprintf(&txbuf[2*i], "\r");
+                               sprintf(&local_txbuf[2*i], "\r");
                        }
 
                        elm->drop_next_line = 1;
                        elm->state = ELM_RECEIVING;
                }
 
-               elm327_send(elm, txbuf, strlen(txbuf));
+               elm327_send(elm, local_txbuf, strlen(local_txbuf));
        } else {
                /* Enter CAN monitor mode */
                elm327_send(elm, "ATMA\r", 5);
@@ -677,7 +706,7 @@ static void elm327_parse_rxbuf(struct elmcan *elm)
                        /* Line exceeds buffer. It's probably all garbage.
                         * Did we even connect at the right baud rate?
                         */
-                       pr_err("RX buffer overflow. Faulty ELM327 connected?\n");
+                       netdev_err(elm->dev, "RX buffer overflow. Faulty ELM327 connected?\n");
                        elm327_hw_failure(elm);
                        return;
                } else if (len == elm->rxfill) {
@@ -915,7 +944,7 @@ static void elmcan_ldisc_rx(struct tty_struct *tty,
        /* Read the characters out of the buffer */
        while (count-- && elm->rxfill < sizeof(elm->rxbuf)) {
                if (fp && *fp++) {
-                       pr_err("Error in received character stream. Check your wiring.");
+                       netdev_err(elm->dev, "Error in received character stream. Check your wiring.");
 
                        spin_lock_bh(&elm->lock);
                        elm327_hw_failure(elm);
@@ -931,7 +960,7 @@ static void elmcan_ldisc_rx(struct tty_struct *tty,
        }
 
        if (count >= 0) {
-               pr_err("Receive buffer overflowed. Bad chip or wiring?");
+               netdev_err(elm->dev, "Receive buffer overflowed. Bad chip or wiring?");
 
                spin_lock_bh(&elm->lock);
                elm327_hw_failure(elm);
@@ -1013,19 +1042,30 @@ static void elmcan_ldisc_tx_wakeup(struct tty_struct *tty)
 
 
 
-/* Some fake bit timings to allow bitrate setting */
-static const struct can_bittiming_const elmcan_bittiming_const = {
-       .name = "elmcan",
-       .tseg1_min = 1,
-       .tseg1_max = 1,
-       .tseg2_min = 0,
-       .tseg2_max = 0,
-       .sjw_max = 1,
-       .brp_min = 1,
-       .brp_max = 500,
-       .brp_inc = 1,
+/* ELM327 can only handle bitrates that are integer divisors of 500 kHz,
+ * or 7/8 of that. Divisors are 1 to 64.
+ * Currently we don't implement support for 7/8 rates.
+ */
+static const u32 elmcan_bitrate_const[64] = {
+       7812, 7936, 8064, 8196, 8333, 8474, 8620, 8771,
+       8928, 9090, 9259, 9433, 9615, 9803, 10000, 10204,
+       10416, 10638, 10869, 11111, 11363, 11627, 11904, 12195,
+       12500, 12820, 13157, 13513, 13888, 14285, 14705, 15151,
+       15625, 16129, 16666, 17241, 17857, 18518, 19230, 20000,
+       20833, 21739, 22727, 23809, 25000, 26315, 27777, 29411,
+       31250, 33333, 35714, 38461, 41666, 45454, 50000, 55555,
+       62500, 71428, 83333, 100000, 125000, 166666, 250000, 500000
 };
 
+/* Dummy function to claim we're changing the bitrate.
+ * We actually do this when opening the net device.
+ */
+static int elmcan_do_set_bittiming(struct net_device *netdev)
+{
+       return 0;
+}
+
+
 /*
  * Open the high-level part of the elmcan channel.
  * This function is called by the TTY module when the
@@ -1061,8 +1101,9 @@ static int elmcan_ldisc_open(struct tty_struct *tty)
 
        /* Configure CAN metadata */
        elm->can.state = CAN_STATE_STOPPED;
-       elm->can.clock.freq = 1000000;
-       elm->can.bittiming_const = &elmcan_bittiming_const;
+       elm->can.bitrate_const = elmcan_bitrate_const;
+       elm->can.bitrate_const_cnt = ARRAY_SIZE(elmcan_bitrate_const);
+       elm->can.do_set_bittiming = elmcan_do_set_bittiming;
        elm->can.ctrlmode_supported = CAN_CTRLMODE_LISTENONLY;
 
        /* Configure netlink interface */
@@ -1151,7 +1192,6 @@ static int elmcan_ldisc_ioctl(struct tty_struct *tty, struct file *file,
        struct elmcan *elm = get_elm(tty);
        unsigned int tmp;
 
-       /* First make sure we're connected. */
        if (!elm)
                return -EINVAL;