shell: Add a Segger RTT backend

Fixes: #8394

Signed-off-by: Christoph Schramm <schramm@makaio.com>

include/shell/shell_rtt.h

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2018 Makaio GmbH
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef SHELL_RTT_H__
+#define SHELL_RTT_H__
+
+#include <shell/shell.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern const struct shell_transport_api shell_rtt_transport_api;
+
+struct shell_rtt {
+	shell_transport_handler_t handler;
+	struct k_timer timer;
+	void *context;
+	u8_t rx[5];
+	size_t rx_cnt;
+};
+
+#define SHELL_RTT_DEFINE(_name)					\
+	static struct shell_rtt _name##_shell_rtt;			\
+	struct shell_transport _name = {				\
+		.api = &shell_rtt_transport_api,			\
+		.ctx = (struct shell_rtt *)&_name##_shell_rtt		\
+	}
+
+/**
+ * @brief Function provides pointer to shell rtt backend instance.
+ *
+ * Function returns pointer to the shell rtt instance. This instance can be
+ * next used with shell_execute_cmd function in order to test commands behavior.
+ *
+ * @returns Pointer to the shell instance.
+ */
+const struct shell *shell_backend_rtt_get_ptr(void);
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* SHELL_RTT_H__ */

subsys/shell/CMakeLists.txt

@@ -28,6 +28,11 @@ zephyr_sources_ifdef(
   shell_dummy.c
 )
 
+zephyr_sources_ifdef(
+  CONFIG_SHELL_BACKEND_RTT
+  shell_rtt.c
+)
+
 zephyr_sources_ifdef(
   CONFIG_SHELL_CMDS
   shell_cmds.c

subsys/shell/Kconfig.backends

@@ -21,6 +21,12 @@ config SHELL_BACKEND_SERIAL
 	help
 	  Enable serial backends.
 
+config SHELL_BACKEND_RTT
+	bool "Enable RTT backend."
+	select RTT_CONSOLE
+	help
+	  Enable RTT backend.
+
 config SHELL_BACKEND_DUMMY
 	bool "Enable dummy backend."
 	help

subsys/shell/shell_rtt.c

@@ -0,0 +1,116 @@
+/*
+ * Copyright (c) 2018 Makaio GmbH
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <shell/shell_rtt.h>
+#include <init.h>
+#include <rtt/SEGGER_RTT.h>
+#include <logging/sys_log.h>
+
+SHELL_RTT_DEFINE(shell_transport_rtt);
+SHELL_DEFINE(rtt_shell, "rtt:~$ ", &shell_transport_rtt, 10,
+	     SHELL_FLAG_OLF_CRLF);
+
+static struct k_thread rtt_rx_thread;
+static K_THREAD_STACK_DEFINE(rtt_rx_stack, 1024);
+
+static void shell_rtt_rx_process(struct shell_rtt *sh_rtt)
+{
+	u32_t count;
+
+	while (1) {
+		count = SEGGER_RTT_Read(0, sh_rtt->rx, sizeof(sh_rtt->rx));
+
+		if (count > 0) {
+			sh_rtt->rx_cnt = count;
+			sh_rtt->handler(SHELL_TRANSPORT_EVT_RX_RDY, sh_rtt->context);
+		}
+
+		k_sleep(K_MSEC(10));
+	}
+}
+
+
+static int init(const struct shell_transport *transport,
+		const void *config,
+		shell_transport_handler_t evt_handler,
+		void *context)
+{
+	struct shell_rtt *sh_rtt = (struct shell_rtt *)transport->ctx;
+
+	sh_rtt->handler = evt_handler;
+	sh_rtt->context = context;
+
+	k_thread_create(&rtt_rx_thread, rtt_rx_stack,
+			K_THREAD_STACK_SIZEOF(rtt_rx_stack),
+			(k_thread_entry_t)shell_rtt_rx_process,
+			sh_rtt, NULL, NULL, K_PRIO_COOP(8),
+			0, K_NO_WAIT);
+
+	return 0;
+}
+
+static int uninit(const struct shell_transport *transport)
+{
+	return 0;
+}
+
+static int enable(const struct shell_transport *transport, bool blocking)
+{
+	return 0;
+}
+
+static int write(const struct shell_transport *transport,
+		 const void *data, size_t length, size_t *cnt)
+{
+	struct shell_rtt *sh_rtt = (struct shell_rtt *)transport->ctx;
+	const u8_t *data8 = (const u8_t *)data;
+
+	SEGGER_RTT_Write(0, data8, length);
+	*cnt = length;
+
+	sh_rtt->handler(SHELL_TRANSPORT_EVT_TX_RDY, sh_rtt->context);
+	return 0;
+}
+
+static int read(const struct shell_transport *transport,
+		void *data, size_t length, size_t *cnt)
+{
+	struct shell_rtt *sh_rtt = (struct shell_rtt *)transport->ctx;
+
+	if (sh_rtt->rx_cnt) {
+		memcpy(data, sh_rtt->rx, sh_rtt->rx_cnt);
+		*cnt = sh_rtt->rx_cnt;
+		sh_rtt->rx_cnt = 0;
+	} else {
+		*cnt = 0;
+	}
+
+	return 0;
+}
+
+const struct shell_transport_api shell_rtt_transport_api = {
+	.init = init,
+	.uninit = uninit,
+	.enable = enable,
+	.write = write,
+	.read = read
+};
+
+static int enable_shell_rtt(struct device *arg)
+{
+	ARG_UNUSED(arg);
+
+	shell_init(&rtt_shell, NULL, false, false, LOG_LEVEL_INF);
+
+	return 0;
+}
+
+/* Function is used for testing purposes */
+const struct shell *shell_backend_rtt_get_ptr(void)
+{
+	return &rtt_shell;
+}
+SYS_INIT(enable_shell_rtt, POST_KERNEL, 0);