logging: Add qemu_x86_64 backend

Added backend for qemu_x86_64

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>

boards/x86_64/qemu_x86_64/qemu_x86_64_defconfig

@@ -14,3 +14,4 @@ CONFIG_IDLE_STACK_SIZE=1024
 CONFIG_TEST_EXTRA_STACKSIZE=2048
 CONFIG_SRAM_BASE_ADDRESS=0x100000
 CONFIG_SRAM_SIZE=8192
+CONFIG_LOG_BACKEND_QEMU_X86_64=y

subsys/logging/CMakeLists.txt

@@ -42,3 +42,8 @@ zephyr_sources_ifdef(
   CONFIG_LOG_BACKEND_SWO
   log_backend_swo.c
 )
+
+zephyr_sources_ifdef(
+  CONFIG_LOG_BACKEND_QEMU_X86_64
+  log_backend_qemu_x86_64.c
+)

subsys/logging/Kconfig

@@ -372,6 +372,12 @@ config LOG_BACKEND_NATIVE_POSIX
 	help
 	  Enable backend in native_posix
 
+config LOG_BACKEND_QEMU_X86_64
+	bool "Enable QEMU x86_64 backend"
+	depends on BOARD_QEMU_X86_64
+	help
+	  Enable backend for qemu_x86_64 board
+
 config LOG_BACKEND_XTENSA_SIM
 	bool "Enable xtensa simulator backend"
 	depends on SOC_XTENSA_SAMPLE_CONTROLLER

subsys/logging/log_backend_qemu_x86_64.c

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2019 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <stddef.h>
+#include <logging/log_backend.h>
+#include <logging/log_msg.h>
+#include <logging/log_output.h>
+#include "log_backend_std.h"
+#include <../core/serial.h>
+
+static int char_out(u8_t *data, size_t length, void *ctx)
+{
+	ARG_UNUSED(ctx);
+	for (int i = 0; i < length; ++i) {
+		serout(data[i]);
+	}
+	return length;
+}
+
+static char buf;
+LOG_OUTPUT_DEFINE(log_output, char_out, &buf, sizeof(buf));
+
+static void put(const struct log_backend *const backend,
+		struct log_msg *msg)
+{
+	ARG_UNUSED(backend);
+	log_backend_std_put(&log_output, 0, msg);
+}
+
+static void panic(struct log_backend const *const backend)
+{
+	ARG_UNUSED(backend);
+	log_backend_std_panic(&log_output);
+}
+
+static void dropped(const struct log_backend *const backend, u32_t cnt)
+{
+	ARG_UNUSED(backend);
+
+	log_backend_std_dropped(&log_output, cnt);
+}
+
+static void sync_string(const struct log_backend *const backend,
+		     struct log_msg_ids src_level, u32_t timestamp,
+		     const char *fmt, va_list ap)
+{
+	ARG_UNUSED(backend);
+	log_backend_std_sync_string(&log_output, 0, src_level,
+			    timestamp, fmt, ap);
+}
+
+static void sync_hexdump(const struct log_backend *const backend,
+			 struct log_msg_ids src_level, u32_t timestamp,
+			 const char *metadata, const u8_t *data, u32_t length)
+{
+	ARG_UNUSED(backend);
+	log_backend_std_sync_hexdump(&log_output, 0, src_level,
+				     timestamp, metadata, data, length);
+}
+
+const struct log_backend_api log_backend_qemu_x86_64_api = {
+	.put = IS_ENABLED(CONFIG_LOG_IMMEDIATE) ? NULL : put,
+	.put_sync_string = IS_ENABLED(CONFIG_LOG_IMMEDIATE) ?
+			sync_string : NULL,
+	.put_sync_hexdump = IS_ENABLED(CONFIG_LOG_IMMEDIATE) ?
+			sync_hexdump : NULL,
+	.panic = panic,
+	.dropped = IS_ENABLED(CONFIG_LOG_IMMEDIATE) ? NULL : dropped,
+};
+
+LOG_BACKEND_DEFINE(log_backend_qemu_x86_64, log_backend_qemu_x86_64_api, true);