drivers/at: Add at_urc_isr module to process URCs upon arrival

drivers/Makefile.dep

@@ -43,6 +43,14 @@ ifneq (,$(filter at,$(USEMODULE)))
   USEMODULE += fmt
   USEMODULE += isrpipe
   USEMODULE += isrpipe_read_timeout
+
+  _AT_ISR_MODULE := $(filter at_urc_isr_%,$(USEMODULE))
+  ifneq (,$(_AT_ISR_MODULE))
+    # pull in the correspondant event_thread_<priority> module
+    USEMODULE += $(_AT_ISR_MODULE:at_urc_isr_%=event_thread_%)
+    USEMODULE += at_urc
+    USEMODULE += at_urc_isr
+  endif
 endif
 
 ifneq (,$(filter at24c%,$(USEMODULE)))

drivers/at/at.c

@@ -14,6 +14,7 @@
 #include "isrpipe.h"
 #include "isrpipe/read_timeout.h"
 #include "periph/uart.h"
+#include "event/thread.h"
 
 #define ENABLE_DEBUG (0)
 #include "debug.h"
@@ -22,39 +23,79 @@
 #define AT_PRINT_INCOMING (0)
 #endif
 
-static void _isrpipe_write_one_wrapper(void *_isrpipe, uint8_t data)
+#if defined(MODULE_AT_URC_ISR_LOW)
+#define AT_EVENT_PRIO EVENT_PRIO_LOW
+#elif defined(MODULE_AT_URC_ISR_MEDIUM)
+#define AT_EVENT_PRIO EVENT_PRIO_MEDIUM
+#elif defined(MODULE_AT_URC_ISR_HIGH)
+#define AT_EVENT_PRIO EVENT_PRIO_HIGH
+#endif
+
+#if defined(MODULE_AT_URC_ISR)
+static void _event_process_urc(event_t *_event)
 {
-    isrpipe_write_one(_isrpipe, data);
+    at_dev_t *dev = (at_dev_t *)container_of(_event, at_dev_t, event);
+    at_process_urc(dev, 1000);
+}
+#endif
+
+static void _isrpipe_write_one_wrapper(void *_dev, uint8_t data)
+{
+    at_dev_t *dev = (at_dev_t *) _dev;
+    isrpipe_write_one(&dev->isrpipe, data);
+#if defined(MODULE_AT_URC_ISR)
+    if (data == AT_RECV_EOL_2[0] && !dev->awaiting_response) {
+        event_post(AT_EVENT_PRIO, &dev->event);
+    }
+#endif
 }
 
 int at_dev_init(at_dev_t *dev, uart_t uart, uint32_t baudrate, char *buf, size_t bufsize)
 {
     dev->uart = uart;
+
+#if IS_USED(MODULE_AT_URC_ISR)
+    dev->awaiting_response = false;
+    dev->event.handler = _event_process_urc;
+#endif
+
     isrpipe_init(&dev->isrpipe, (uint8_t *)buf, bufsize);
 
     return uart_init(uart, baudrate, _isrpipe_write_one_wrapper,
-                     &dev->isrpipe);
+                     dev);
 }
 
 int at_expect_bytes(at_dev_t *dev, const char *bytes, uint32_t timeout)
 {
+    int res = 0;
+
+#if IS_USED(MODULE_AT_URC_ISR)
+    dev->awaiting_response = true;
+#endif
+
     while (*bytes) {
         char c;
-        int res;
         if ((res = isrpipe_read_timeout(&dev->isrpipe, (uint8_t *)&c, 1, timeout)) == 1) {
             if (AT_PRINT_INCOMING) {
                 print(&c, 1);
             }
             if (c != *bytes++) {
-                return -1;
+                res = -1;
+                goto out;
             }
         }
         else {
-            return res;
+            goto out;
         }
     }
+    res = 0;
 
-    return 0;
+out:
+#if IS_USED(MODULE_AT_URC_ISR)
+    dev->awaiting_response = false;
+#endif
+
+    return res;
 }
 
 void at_send_bytes(at_dev_t *dev, const char *bytes, size_t len)
@@ -66,6 +107,10 @@ ssize_t at_recv_bytes(at_dev_t *dev, char *bytes, size_t len, uint32_t timeout)
 {
     char *resp_pos = bytes;
 
+#if IS_USED(MODULE_AT_URC_ISR)
+    dev->awaiting_response = true;
+#endif
+
     while (len) {
         int read_res;
         if ((read_res = isrpipe_read_timeout(&dev->isrpipe, (uint8_t *)resp_pos,
@@ -78,6 +123,10 @@ ssize_t at_recv_bytes(at_dev_t *dev, char *bytes, size_t len, uint32_t timeout)
         }
     }
 
+#if IS_USED(MODULE_AT_URC_ISR)
+    dev->awaiting_response = false;
+#endif
+
     return (resp_pos - bytes);
 }
 
@@ -86,9 +135,13 @@ int at_recv_bytes_until_string(at_dev_t *dev, const char *string,
 {
     size_t len = 0;
     char *_string = (char *)string;
+    int res = 0;
+
+#if IS_USED(MODULE_AT_URC_ISR)
+    dev->awaiting_response = true;
+#endif
 
     while (*_string && len < *bytes_len) {
-        int res;
         char c;
         if ((res = isrpipe_read_timeout(&dev->isrpipe, (uint8_t *)&c, 1, timeout)) == 1) {
             if (AT_PRINT_INCOMING) {
@@ -101,12 +154,16 @@ int at_recv_bytes_until_string(at_dev_t *dev, const char *string,
             len++;
         }
         else {
-            *bytes_len = len;
+            break;
-            return res;
         }
     }
     *bytes_len = len;
-    return 0;
+
+#if IS_USED(MODULE_AT_URC_ISR)
+    dev->awaiting_response = false;
+#endif
+
+    return res;
 }
 
 int at_send_cmd(at_dev_t *dev, const char *command, uint32_t timeout)
@@ -134,10 +191,18 @@ void at_drain(at_dev_t *dev)
     uint8_t _tmp[16];
     int res;
 
+#if IS_USED(MODULE_AT_URC_ISR)
+    dev->awaiting_response = true;
+#endif
+
     do {
         /* consider no character within 10ms "drained" */
         res = isrpipe_read_timeout(&dev->isrpipe, _tmp, sizeof(_tmp), 10000U);
     } while (res > 0);
+
+#if IS_USED(MODULE_AT_URC_ISR)
+    dev->awaiting_response = false;
+#endif
 }
 
 ssize_t at_send_cmd_get_resp(at_dev_t *dev, const char *command,
@@ -285,6 +350,10 @@ ssize_t at_readline(at_dev_t *dev, char *resp_buf, size_t len, bool keep_eol, ui
     ssize_t res = -1;
     char *resp_pos = resp_buf;
 
+#if IS_USED(MODULE_AT_URC_ISR)
+    dev->awaiting_response = true;
+#endif
+
     memset(resp_buf, 0, len);
 
     while (len) {
@@ -315,6 +384,10 @@ ssize_t at_readline(at_dev_t *dev, char *resp_buf, size_t len, bool keep_eol, ui
     }
 
 out:
+#if IS_USED(MODULE_AT_URC_ISR)
+    dev->awaiting_response = false;
+#endif
+
     if (res < 0) {
         *resp_buf = '\0';
     }

drivers/include/at.h

@@ -22,6 +22,28 @@
  *
  * As a debugging aid, when compiled with "-DAT_PRINT_INCOMING=1", every input
  * byte gets printed.
+ *
+ * ## Unsolicited Result Codes (URC) ##
+ * An unsolicited result code is a string message that is not triggered as a
+ * information text response to a previous AT command and can be output at any
+ * time to inform a specific event or status change.
+ *
+ * The module provides a basic URC handling by adding the `at_urc` module to the
+ * application. This allows to @ref at_add_urc "register" and
+ * @ref at_remove_urc "de-register" URC strings to check. Later,
+ * @ref at_process_urc can be called to check if any of the registered URCs have
+ * been detected. If a registered URC has been detected the correspondant
+ * @ref at_urc_t::cb "callback function" is called. The mode of operation
+ * requires that the user of the module processes periodically the URCs.
+ *
+ * Alternatively, one of the `at_urc_isr_<priority>` modules can be included.
+ * `priority` can be one of `low`, `medium` or `highest`, which correspond to
+ * the priority of the thread that processes the URCs. For more information on
+ * the priorities check the @ref sys_event module. This will extend the
+ * functionality of `at_urc` by processing the URCs when the @ref AT_RECV_EOL_2
+ * character is detected and there is no pending response. This works by posting
+ * an @ref sys_event "event" to an event thread that processes the URCs.
+ *
  * @{
  *
  * @file
@@ -42,6 +64,8 @@
 #include "clist.h"
 #include "kernel_defines.h"
 
+#include "event.h"
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -169,6 +193,10 @@ typedef struct {
     uart_t uart;            /**< UART device where the AT device is attached */
 #ifdef MODULE_AT_URC
     clist_node_t urc_list;  /**< list to keep track of all registered urc's */
+#ifdef MODULE_AT_URC_ISR
+    bool awaiting_response; /**< indicates if the driver waits for a response */
+    event_t event;          /**< event posted from ISR to process urc's */
+#endif
 #endif
 } at_dev_t;
 

makefiles/pseudomodules.inc.mk

@@ -1,4 +1,8 @@
 PSEUDOMODULES += at_urc
+PSEUDOMODULES += at_urc_isr
+PSEUDOMODULES += at_urc_isr_low
+PSEUDOMODULES += at_urc_isr_medium
+PSEUDOMODULES += at_urc_isr_highest
 PSEUDOMODULES += at24c%
 PSEUDOMODULES += base64url
 PSEUDOMODULES += can_mbox

tests/driver_at/Makefile

@@ -2,6 +2,9 @@ include ../Makefile.tests_common
 
 USEMODULE += shell
 USEMODULE += at
-USEMODULE += at_urc
+USEMODULE += at_urc_isr_medium
+
+# we are printing from the event thread, we need more stack
+CFLAGS += -DEVENT_THREAD_MEDIUM_STACKSIZE=1024
 
 include $(RIOTBASE)/Makefile.include