Use RTT as a module, rebased from raspberrypi#775, with compiler fixes

.gitmodules

@@ -13,3 +13,6 @@
 [submodule "lib/btstack"]
 	path = lib/btstack
 	url = https://github.com/bluekitchen/btstack.git
+[submodule "lib/rtt"]
+	path = lib/rtt
+	url = [email protected]:adfernandes/segger-rtt.git

src/rp2_common/CMakeLists.txt

@@ -54,6 +54,7 @@ if (NOT PICO_BARE_METAL)
     pico_add_subdirectory(pico_stdio)
     pico_add_subdirectory(pico_stdio_semihosting)
     pico_add_subdirectory(pico_stdio_uart)
+    pico_add_subdirectory(pico_stdio_rtt)
 
     pico_add_subdirectory(cmsis)
     pico_add_subdirectory(tinyusb)
@@ -84,4 +85,4 @@ set(CMAKE_EXECUTABLE_SUFFIX "${CMAKE_EXECUTABLE_SUFFIX}" PARENT_SCOPE)
 pico_add_doxygen(${CMAKE_CURRENT_LIST_DIR})
 pico_add_doxygen_exclude(${CMAKE_CURRENT_LIST_DIR}/cmsis)
 
-pico_promote_common_scope_vars()
+pico_promote_common_scope_vars()

src/rp2_common/pico_stdio/include/pico/stdio.h

@@ -51,14 +51,14 @@ typedef struct stdio_driver stdio_driver_t;
 /*! \brief Initialize all of the present standard stdio types that are linked into the binary.
  * \ingroup pico_stdio
  *
- * Call this method once you have set up your clocks to enable the stdio support for UART, USB
- * and semihosting based on the presence of the respective libraries in the binary.
+ * Call this method once you have set up your clocks to enable the stdio support for UART, USB,
+ * semihosting, and RTT based on the presence of the respective libraries in the binary.
  *
  * When stdio_usb is configured, this method can be optionally made to block, waiting for a connection
  * via the variables specified in \ref stdio_usb_init (i.e. \ref PICO_STDIO_USB_CONNECT_WAIT_TIMEOUT_MS)
  *
  * \return true if at least one output was successfully initialized, false otherwise.
- * \see stdio_uart, stdio_usb, stdio_semihosting
+ * \see stdio_uart, stdio_usb, stdio_semihosting, stdio_rtt
  */
 bool stdio_init_all(void);
 

src/rp2_common/pico_stdio/stdio.c

@@ -32,6 +32,10 @@
 #include "pico/stdio_semihosting.h"
 #endif
 
+#if LIB_PICO_STDIO_RTT
+#include "pico/stdio_rtt.h"
+#endif
+
 #define STDIO_HANDLE_STDIN  0
 #define STDIO_HANDLE_STDOUT 1
 #define STDIO_HANDLE_STDERR 2
@@ -295,6 +299,11 @@ bool stdio_init_all(void) {
     rc = true;
 #endif
 
+#if LIB_PICO_STDIO_RTT
+    stdio_rtt_init();
+    rc = true;
+#endif
+
 #if LIB_PICO_STDIO_USB
     rc |= stdio_usb_init();
 #endif
@@ -331,7 +340,7 @@ void stdio_set_translate_crlf(stdio_driver_t *driver, bool enabled) {
     // Suppress -Wunused-parameter
     (void)driver;
     (void)enabled;
-    
+
     panic_unsupported();
 #endif
 }

src/rp2_common/pico_stdio_rtt/CMakeLists.txt

@@ -0,0 +1,15 @@
+pico_add_library(pico_stdio_rtt)
+
+target_sources(pico_stdio_rtt
+    INTERFACE
+        stdio_rtt.c
+        segger_rtt.c
+)
+
+target_include_directories(pico_stdio_rtt_headers
+    INTERFACE
+        ./include
+        ../../../lib/rtt/RTT
+)
+
+pico_mirrored_target_link_libraries(pico_stdio_rtt INTERFACE pico_stdio)

src/rp2_common/pico_stdio_rtt/include/pico/stdio_rtt.h

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef _PICO_STDIO_RTT_H
+#define _PICO_STDIO_RTT_H
+
+#include "pico/stdio.h"
+
+/** \brief Support for stdin/stdout using SEGGER RTT
+ *  \defgroup pico_stdio_rtt pico_stdio_rtt
+ *  \ingroup pico_stdio
+ *
+ *  Linking this library or calling `pico_enable_stdio_rtt(TARGET)` in the CMake (which
+ *  achieves the same thing) will add RTT to the drivers used for standard output
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern stdio_driver_t stdio_rtt;
+
+/*! \brief Explicitly initialize stdin/stdout over RTT and add it to the current set of stdin/stdout drivers
+ *  \ingroup pico_stdio_rtt
+ *
+ * \note this method is automatically called by \ref stdio_init_all() if `pico_stdio_rtt` is included in the build
+ */
+void stdio_rtt_init(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

src/rp2_common/pico_stdio_rtt/segger_rtt.c

@@ -0,0 +1,16 @@
+/*
+
+    We use this round-about way of including the Segger RTT source file
+    because we need to suppress the "cast-align" and "cast-qual" warnings,
+    and cmake will not let us change the COMPILE_OPTIONS for a single
+    source file if the target has one source file in the current directory tree
+    and another source file in a directory outside the current directory tree.
+
+    See https://gitlab.kitware.com/cmake/cmake/-/issues/20128 for more details.
+
+ */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wcast-align"
+#pragma GCC diagnostic ignored "-Wcast-qual"
+#include "../../../lib/rtt/RTT/SEGGER_RTT.c"
+#pragma GCC diagnostic pop

src/rp2_common/pico_stdio_rtt/stdio_rtt.c

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include "pico/binary_info.h"
+#include "pico/stdio/driver.h"
+#include "pico/stdio_rtt.h"
+#include "SEGGER_RTT.h"
+
+void stdio_rtt_init(void) {
+    stdio_set_driver_enabled(&stdio_rtt, true);
+    stdio_bi_decl_if_func_used(bi_program_feature("RTT stdin / stdout"));
+}
+
+static void stdio_rtt_out_chars(const char *buf, int length) {
+    SEGGER_RTT_Write(0, buf, length);
+}
+
+static int stdio_rtt_in_chars(char *buf, int length) {
+    return SEGGER_RTT_Read(0, buf, length);
+}
+
+stdio_driver_t stdio_rtt = {
+    .out_chars = stdio_rtt_out_chars,
+    .in_chars = stdio_rtt_in_chars,
+};

src/rp2_common/pico_stdlib/CMakeLists.txt

@@ -3,7 +3,9 @@ option(PICO_STDIO_UART "Globally enable stdio UART" 1)
 # PICO_CMAKE_CONFIG: PICO_STDIO_USB, OPTION: Globally enable stdio USB, default=0, group=pico_stdlib
 option(PICO_STDIO_USB "Globally enable stdio USB" 0)
 # PICO_CMAKE_CONFIG: PICO_STDIO_SEMIHOSTING, OPTION: Globally enable stdio semihosting, default=0, group=pico_stdlib
-option(PICO_STDIO_SEMIHOSTING "Globally enable stdio semi-hosting" 0)
+option(PICO_STDIO_SEMIHOSTING "Globally enable stdio semihosting" 0)
+# PICO_CMAKE_CONFIG: PICO_STDIO_RTT, OPTION: Globally enable stdio RTT, default=0, group=pico_stdlib
+option(PICO_STDIO_RTT "Globally enable stdio rtt" 0)
 
 if (NOT TARGET pico_stdlib)
     pico_add_impl_library(pico_stdlib)
@@ -33,6 +35,10 @@ if (NOT TARGET pico_stdlib)
         set_target_properties(${TARGET} PROPERTIES PICO_TARGET_STDIO_SEMIHOSTING ${ENABLED})
     endfunction()
 
+    function(pico_enable_stdio_rtt TARGET ENABLED)
+        set_target_properties(${TARGET} PROPERTIES PICO_TARGET_STDIO_RTT ${ENABLED})
+    endfunction()
+
     if (TARGET pico_stdio_uart)
         target_link_libraries(pico_stdlib INTERFACE $<IF:$<BOOL:$<IF:$<STREQUAL:$<TARGET_PROPERTY:PICO_TARGET_STDIO_UART>,>,${PICO_STDIO_UART},$<TARGET_PROPERTY:PICO_TARGET_STDIO_UART>>>,pico_stdio_uart,>)
         target_link_libraries(pico_stdlib_headers INTERFACE $<IF:$<BOOL:$<IF:$<STREQUAL:$<TARGET_PROPERTY:PICO_TARGET_STDIO_UART>,>,${PICO_STDIO_UART},$<TARGET_PROPERTY:PICO_TARGET_STDIO_UART>>>,pico_stdio_uart_headers,>)
@@ -48,4 +54,9 @@ if (NOT TARGET pico_stdlib)
         target_link_libraries(pico_stdlib_headers INTERFACE $<IF:$<BOOL:$<IF:$<STREQUAL:$<TARGET_PROPERTY:PICO_TARGET_STDIO_SEMIHOSTING>,>,${PICO_STDIO_SEMIHOSTING},$<TARGET_PROPERTY:PICO_TARGET_STDIO_SEMIHOSTING>>>,pico_stdio_semihosting_headers,>)
     endif()
 
+    if (TARGET pico_stdio_rtt)
+        target_link_libraries(pico_stdlib INTERFACE $<IF:$<BOOL:$<IF:$<STREQUAL:$<TARGET_PROPERTY:PICO_TARGET_STDIO_RTT>,>,${PICO_STDIO_RTT},$<TARGET_PROPERTY:PICO_TARGET_STDIO_RTT>>>,pico_stdio_rtt,>)
+        target_link_libraries(pico_stdlib_headers INTERFACE $<IF:$<BOOL:$<IF:$<STREQUAL:$<TARGET_PROPERTY:PICO_TARGET_STDIO_RTT>,>,${PICO_STDIO_RTT},$<TARGET_PROPERTY:PICO_TARGET_STDIO_RTT>>>,pico_stdio_rtt_headers,>)
+    endif()
+
 endif()