Clear TTY_DO_WRITE_WAKEUP bit on uart_side_failure
[elmcan.git] / module / elmcan.c
index 85c656585f1551bea4328b16a8f1fcc7021dfe3e..c5723dedb92ac6cf28f1ae9bfccc23c02fe09a36 100644 (file)
@@ -2,8 +2,7 @@
 /* ELM327 based CAN interface driver (tty line discipline)
  *
  * This driver started as a derivative of linux/drivers/net/can/slcan.c
- * and my thanks go to the original authors for their inspiration, even
- * after almost none of their code is left.
+ * and my thanks go to the original authors for their inspiration.
  *
  * elmcan.c Author : Max Staudt <max-linux@enpas.org>
  * slcan.c Author  : Oliver Hartkopp <socketcan@hartkopp.net>
@@ -44,8 +43,8 @@
 #include <linux/can/rx-offload.h>
 
 /* Line discipline ID number.
- * N_DEVELOPMENT will likely be defined from Linux 5.18 onwards:
- * https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git/commit/?h=tty-next&id=c2faf737abfb10f88f2d2612d573e9edc3c42c37
+ * Starting with Linux v5.18-rc1, N_DEVELOPMENT is defined as 29:
+ * https://github.com/torvalds/linux/commit/c2faf737abfb10f88f2d2612d573e9edc3c42c37
  */
 #ifndef N_DEVELOPMENT
 #define N_DEVELOPMENT 29
@@ -142,7 +141,7 @@ static void elm327_send(struct elmcan *elm, const void *buf, size_t len)
 {
        int written;
 
-       lockdep_assert_held(elm->lock);
+       lockdep_assert_held(&elm->lock);
 
        if (elm->uart_side_failure)
                return;
@@ -161,9 +160,7 @@ static void elm327_send(struct elmcan *elm, const void *buf, size_t len)
        elm->txleft = len - written;
        elm->txhead = elm->txbuf + written;
 
-       if (!elm->txleft)
-               netif_wake_queue(elm->dev);
-       else
+       if (elm->txleft)
                set_bit(TTY_DO_WRITE_WAKEUP, &elm->tty->flags);
 }
 
@@ -174,7 +171,7 @@ static void elm327_send(struct elmcan *elm, const void *buf, size_t len)
  */
 static void elm327_kick_into_cmd_mode(struct elmcan *elm)
 {
-       lockdep_assert_held(elm->lock);
+       lockdep_assert_held(&elm->lock);
 
        if (elm->state != ELM327_STATE_GETDUMMYCHAR &&
            elm->state != ELM327_STATE_GETPROMPT) {
@@ -187,7 +184,7 @@ static void elm327_kick_into_cmd_mode(struct elmcan *elm)
 /* Schedule a CAN frame and necessary config changes to be sent to the TTY. */
 static void elm327_send_frame(struct elmcan *elm, struct can_frame *frame)
 {
-       lockdep_assert_held(elm->lock);
+       lockdep_assert_held(&elm->lock);
 
        /* Schedule any necessary changes in ELM327's CAN configuration */
        if (elm->can_frame_to_send.can_id != frame->can_id) {
@@ -249,7 +246,7 @@ static char *elm327_init_script[] = {
 
 static void elm327_init(struct elmcan *elm)
 {
-       lockdep_assert_held(elm->lock);
+       lockdep_assert_held(&elm->lock);
 
        elm->state = ELM327_STATE_NOTINIT;
        elm->can_frame_to_send.can_id = 0x7df; /* ELM327 HW default */
@@ -279,7 +276,7 @@ static void elm327_init(struct elmcan *elm)
 static void elm327_feed_frame_to_netdev(struct elmcan *elm,
                                        struct sk_buff *skb)
 {
-       lockdep_assert_held(elm->lock);
+       lockdep_assert_held(&elm->lock);
 
        if (!netif_running(elm->dev))
                return;
@@ -302,10 +299,12 @@ static inline void elm327_uart_side_failure(struct elmcan *elm)
        struct can_frame *frame;
        struct sk_buff *skb;
 
-       lockdep_assert_held(elm->lock);
+       lockdep_assert_held(&elm->lock);
 
        elm->uart_side_failure = true;
 
+       clear_bit(TTY_DO_WRITE_WAKEUP, &elm->tty->flags);
+
        elm->can.can_stats.bus_off++;
        netif_stop_queue(elm->dev);
        elm->can.state = CAN_STATE_BUS_OFF;
@@ -343,7 +342,7 @@ static void elm327_parse_error(struct elmcan *elm, size_t len)
        struct can_frame *frame;
        struct sk_buff *skb;
 
-       lockdep_assert_held(elm->lock);
+       lockdep_assert_held(&elm->lock);
 
        skb = alloc_can_err_skb(elm->dev, &frame);
        if (!skb)
@@ -410,7 +409,7 @@ static int elm327_parse_frame(struct elmcan *elm, size_t len)
        int datastart;
        int i;
 
-       lockdep_assert_held(elm->lock);
+       lockdep_assert_held(&elm->lock);
 
        skb = alloc_can_skb(elm->dev, &frame);
        if (!skb)
@@ -532,7 +531,7 @@ static int elm327_parse_frame(struct elmcan *elm, size_t len)
 
 static void elm327_parse_line(struct elmcan *elm, size_t len)
 {
-       lockdep_assert_held(elm->lock);
+       lockdep_assert_held(&elm->lock);
 
        /* Skip empty lines */
        if (!len)
@@ -547,8 +546,8 @@ static void elm327_parse_line(struct elmcan *elm, size_t len)
        }
 
        /* Regular parsing */
-       if (elm->state == ELM327_STATE_RECEIVING
-           && elm327_parse_frame(elm, len)) {
+       if (elm->state == ELM327_STATE_RECEIVING &&
+           elm327_parse_frame(elm, len)) {
                /* Parse an error line. */
                elm327_parse_error(elm, len);
 
@@ -566,21 +565,26 @@ static void elm327_handle_prompt(struct elmcan *elm)
         */
        char local_txbuf[sizeof("0102030405060708\r")];
 
-       lockdep_assert_held(elm->lock);
+       lockdep_assert_held(&elm->lock);
 
        if (!elm->cmds_todo) {
                /* Enter CAN monitor mode */
                elm327_send(elm, "ATMA\r", 5);
                elm->state = ELM327_STATE_RECEIVING;
 
+               /* We will be in the default state once this command is
+                * send, so enable the TX packet queue.
+                */
+               netif_wake_queue(elm->dev);
+
                return;
        }
 
        /* Reconfigure ELM327 step by step as indicated by elm->cmds_todo */
        if (test_bit(ELM327_TX_DO_INIT, &elm->cmds_todo)) {
                snprintf(local_txbuf, sizeof(local_txbuf),
-                       "%s",
-                       *elm->next_init_cmd);
+                        "%s",
+                        *elm->next_init_cmd);
 
                elm->next_init_cmd++;
                if (!(*elm->next_init_cmd)) {
@@ -590,38 +594,38 @@ static void elm327_handle_prompt(struct elmcan *elm)
 
        } else if (test_and_clear_bit(ELM327_TX_DO_SILENT_MONITOR, &elm->cmds_todo)) {
                snprintf(local_txbuf, sizeof(local_txbuf),
-                       "ATCSM%i\r",
-                       !(!(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)));
+                        "ATCSM%i\r",
+                        !(!(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)));
 
        } else if (test_and_clear_bit(ELM327_TX_DO_RESPONSES, &elm->cmds_todo)) {
                snprintf(local_txbuf, sizeof(local_txbuf),
-                       "ATR%i\r",
-                       !(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY));
+                        "ATR%i\r",
+                        !(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY));
 
        } else if (test_and_clear_bit(ELM327_TX_DO_CAN_CONFIG, &elm->cmds_todo)) {
                snprintf(local_txbuf, sizeof(local_txbuf),
-                       "ATPC\r");
+                        "ATPC\r");
                set_bit(ELM327_TX_DO_CAN_CONFIG_PART2, &elm->cmds_todo);
 
        } else if (test_and_clear_bit(ELM327_TX_DO_CAN_CONFIG_PART2, &elm->cmds_todo)) {
                snprintf(local_txbuf, sizeof(local_txbuf),
-                       "ATPB%04X\r",
-                       elm->can_config);
+                        "ATPB%04X\r",
+                        elm->can_config);
 
        } else if (test_and_clear_bit(ELM327_TX_DO_CANID_29BIT_HIGH, &elm->cmds_todo)) {
                snprintf(local_txbuf, sizeof(local_txbuf),
-                       "ATCP%02X\r",
-                       (frame->can_id & CAN_EFF_MASK) >> 24);
+                        "ATCP%02X\r",
+                        (frame->can_id & CAN_EFF_MASK) >> 24);
 
        } else if (test_and_clear_bit(ELM327_TX_DO_CANID_29BIT_LOW, &elm->cmds_todo)) {
                snprintf(local_txbuf, sizeof(local_txbuf),
-                       "ATSH%06X\r",
-                       frame->can_id & CAN_EFF_MASK & ((1 << 24) - 1));
+                        "ATSH%06X\r",
+                        frame->can_id & CAN_EFF_MASK & ((1 << 24) - 1));
 
        } else if (test_and_clear_bit(ELM327_TX_DO_CANID_11BIT, &elm->cmds_todo)) {
                snprintf(local_txbuf, sizeof(local_txbuf),
-                       "ATSH%03X\r",
-                       frame->can_id & CAN_SFF_MASK);
+                        "ATSH%03X\r",
+                        frame->can_id & CAN_SFF_MASK);
 
        } else if (test_and_clear_bit(ELM327_TX_DO_CAN_DATA, &elm->cmds_todo)) {
                if (frame->can_id & CAN_RTR_FLAG) {
@@ -629,23 +633,28 @@ static void elm327_handle_prompt(struct elmcan *elm)
                         * Some chips don't send them at all.
                         */
                        snprintf(local_txbuf, sizeof(local_txbuf),
-                               "ATRTR\r");
+                                "ATRTR\r");
                } else {
                        /* Send a regular CAN data frame */
                        int i;
 
                        for (i = 0; i < frame->len; i++) {
                                snprintf(&local_txbuf[2 * i], sizeof(local_txbuf),
-                                       "%02X",
-                                       frame->data[i]);
+                                        "%02X",
+                                        frame->data[i]);
                        }
 
                        snprintf(&local_txbuf[2 * i], sizeof(local_txbuf),
-                               "\r");
+                                "\r");
                }
 
                elm->drop_next_line = 1;
                elm->state = ELM327_STATE_RECEIVING;
+
+               /* We will be in the default state once this command is
+                * send, so enable the TX packet queue.
+                */
+               netif_wake_queue(elm->dev);
        }
 
        elm327_send(elm, local_txbuf, strlen(local_txbuf));
@@ -661,7 +670,7 @@ static bool elm327_is_ready_char(char c)
 
 static void elm327_drop_bytes(struct elmcan *elm, size_t i)
 {
-       lockdep_assert_held(elm->lock);
+       lockdep_assert_held(&elm->lock);
 
        memmove(&elm->rxbuf[0], &elm->rxbuf[i], ELM327_SIZE_RXBUF - i);
        elm->rxfill -= i;
@@ -672,7 +681,7 @@ static void elm327_parse_rxbuf(struct elmcan *elm)
        size_t len;
        int i;
 
-       lockdep_assert_held(elm->lock);
+       lockdep_assert_held(&elm->lock);
 
        switch (elm->state) {
        case ELM327_STATE_NOTINIT:
@@ -824,15 +833,12 @@ static int elmcan_netdev_close(struct net_device *dev)
        elm327_send(elm, ELM327_DUMMY_STRING, 1);
        spin_unlock_bh(&elm->lock);
 
-       /* Give UART one final chance to flush.
-        * This may netif_wake_queue(), so don't netif_stop_queue()
-        * before flushing the worker.
-        */
+       netif_stop_queue(dev);
+
+       /* Give UART one final chance to flush. */
        clear_bit(TTY_DO_WRITE_WAKEUP, &elm->tty->flags);
        flush_work(&elm->tx_work);
 
-       netif_stop_queue(dev);
-
        can_rx_offload_disable(&elm->offload);
        elm->can.state = CAN_STATE_STOPPED;
        can_rx_offload_del(&elm->offload);
@@ -995,16 +1001,15 @@ static void elmcan_ldisc_tx_worker(struct work_struct *work)
                        elm327_uart_side_failure(elm);
                        spin_unlock_bh(&elm->lock);
                        return;
-               } else {
-                       elm->txleft -= written;
-                       elm->txhead += written;
                }
+
+               elm->txleft -= written;
+               elm->txhead += written;
        }
 
        if (!elm->txleft)  {
                clear_bit(TTY_DO_WRITE_WAKEUP, &elm->tty->flags);
                spin_unlock_bh(&elm->lock);
-               netif_wake_queue(elm->dev);
        } else {
                spin_unlock_bh(&elm->lock);
        }