targets: Add Emcraft SmartFusion2 SoM

Change-Id: I5e51ffbb898eecb8f62e6570659ad16339a75223
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/85720
Reviewed-by: Keir Mierle <keir@google.com>
Reviewed-by: Armando Montanez <amontanez@google.com>
Commit-Queue: Sean Keys <skeys@google.com>

8 files changed, 464 insertions, 0 deletions

diff --git a/docs/BUILD.gn b/docs/BUILD.gn
index 2400ca6ce..3fffce501 100644
--- a/docs/BUILD.gn
+++ b/docs/BUILD.gn
@@ -58,6 +58,7 @@ group("target_docs") {
     "$dir_pigweed/targets/android:target_docs",
     "$dir_pigweed/targets/arduino:target_docs",
     "$dir_pigweed/targets/docs:target_docs",
+    "$dir_pigweed/targets/emcraft_sf2_som:docs",
     "$dir_pigweed/targets/host:target_docs",
     "$dir_pigweed/targets/host_device_simulator:target_docs",
     "$dir_pigweed/targets/lm3s6965evb_qemu:target_docs",
diff --git a/targets/emcraft_sf2_som/BUILD.bazel b/targets/emcraft_sf2_som/BUILD.bazel
new file mode 100644
index 000000000..26d04260a
--- /dev/null
+++ b/targets/emcraft_sf2_som/BUILD.bazel
@@ -0,0 +1,58 @@
+# Copyright 2022 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+
+load(
+    "//pw_build:pigweed.bzl",
+    "pw_cc_binary",
+    "pw_cc_library",
+)
+
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])
+
+pw_cc_library(
+    name = "pre_init",
+    srcs = [
+        "boot.cc",
+        "vector_table.c",
+    ],
+    hdrs = [
+        "config/FreeRTOSConfig.h",
+        "config/sf2_mss_hal_conf.h",
+    ],
+    deps = [
+        "//pw_boot",
+        "//pw_boot_cortex_m",
+        "//pw_malloc",
+        "//pw_preprocessor",
+        "//pw_string",
+        "//pw_sys_io_emcraft_sf2",
+        "//third_party/freertos",
+        "//third_party/smartfusion_mss",
+    ],
+)
+
+pw_cc_binary(
+    name = "demo",
+    srcs = [
+        "main.cc",
+    ],
+    deps = [
+        "//pw_thread:thread",
+        "//pw_thread:thread_core",
+        "//pw_thread_freertos:thread",
+        "//third_party/freertos",
+    ],
+)
diff --git a/targets/emcraft_sf2_som/BUILD.gn b/targets/emcraft_sf2_som/BUILD.gn
new file mode 100644
index 000000000..007fa4672
--- /dev/null
+++ b/targets/emcraft_sf2_som/BUILD.gn
@@ -0,0 +1,94 @@
+# Copyright 2022 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+
+import("//build_overrides/pigweed.gni")
+
+import("$dir_pw_build/target_types.gni")
+import("$dir_pw_docgen/docs.gni")
+import("$dir_pw_malloc/backend.gni")
+import("$dir_pw_system/system_target.gni")
+import("$dir_pw_tokenizer/backend.gni")
+import("$dir_pw_toolchain/generate_toolchain.gni")
+config("pw_malloc_active") {
+  if (pw_malloc_BACKEND != "") {
+    defines = [ "PW_MALLOC_ACTIVE=1" ]
+  }
+}
+
+if (current_toolchain != default_toolchain) {
+  pw_source_set("pre_init") {
+    configs = [ ":pw_malloc_active" ]
+    deps = [
+      "$dir_pw_boot",
+      "$dir_pw_boot_cortex_m",
+      "$dir_pw_malloc",
+      "$dir_pw_preprocessor",
+      "$dir_pw_string",
+      "$dir_pw_system",
+      "$dir_pw_third_party/freertos",
+      "$dir_pw_third_party/smartfusion_mss",
+    ]
+    sources = [
+      "boot.cc",
+      "vector_table.c",
+    ]
+  }
+
+  config("config_includes") {
+    include_dirs = [ "config" ]
+  }
+
+  pw_source_set("sf2_mss_hal_config") {
+    public_configs = [ ":config_includes" ]
+    public = [ "config/sf2_mss_hal_conf.h" ]
+  }
+
+  pw_source_set("sf2_freertos_config") {
+    public_configs = [ ":config_includes" ]
+    public_deps = [ "$dir_pw_third_party/freertos:config_assert" ]
+    public = [ "config/FreeRTOSConfig.h" ]
+  }
+}
+
+pw_system_target("emcraft_sf2_som") {
+  cpu = PW_SYSTEM_CPU.CORTEX_M3
+  scheduler = PW_SYSTEM_SCHEDULER.FREERTOS
+
+  link_deps = [ "$dir_pigweed/targets/emcraft_sf2_som:pre_init" ]
+  build_args = {
+    pw_log_BACKEND = dir_pw_log_tokenized
+    pw_tokenizer_GLOBAL_HANDLER_WITH_PAYLOAD_BACKEND = "//pw_system:log"
+    pw_third_party_freertos_CONFIG =
+        "$dir_pigweed/targets/emcraft_sf2_som:sf2_freertos_config"
+    pw_third_party_freertos_PORT = "$dir_pw_third_party/freertos:arm_cm3"
+    pw_boot_cortex_m_LINK_CONFIG_DEFINES = [
+      "PW_BOOT_FLASH_BEGIN=0x00000200",
+      "PW_BOOT_FLASH_SIZE=200K",
+
+      # TODO(pwbug/219): Currently "pw_tokenizer/detokenize_test" requires at
+      # least 6K bytes in heap when using pw_malloc_freelist. The heap size
+      # required for tests should be investigated.
+      "PW_BOOT_HEAP_SIZE=7K",
+      "PW_BOOT_MIN_STACK_SIZE=1K",
+      "PW_BOOT_RAM_BEGIN=0x20000000",
+      "PW_BOOT_RAM_SIZE=64K",
+      "PW_BOOT_VECTOR_TABLE_BEGIN=0x00000000",
+      "PW_BOOT_VECTOR_TABLE_SIZE=512",
+    ]
+  }
+}
+
+pw_doc_group("docs") {
+  sources = [ "target_docs.rst" ]
+}
diff --git a/targets/emcraft_sf2_som/boot.cc b/targets/emcraft_sf2_som/boot.cc
new file mode 100644
index 000000000..284860b2f
--- /dev/null
+++ b/targets/emcraft_sf2_som/boot.cc
@@ -0,0 +1,99 @@
+// Copyright 2022 The Pigweed Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations under
+// the License.
+
+#include "pw_boot/boot.h"
+
+#include <array>
+
+#include "FreeRTOS.h"
+#include "pw_boot_cortex_m/boot.h"
+#include "pw_malloc/malloc.h"
+#include "pw_preprocessor/compiler.h"
+#include "pw_string/util.h"
+#include "pw_sys_io_emcraft_sf2/init.h"
+#include "pw_system/init.h"
+#include "task.h"
+
+namespace {
+
+std::array<StackType_t, configMINIMAL_STACK_SIZE> freertos_idle_stack;
+StaticTask_t freertos_idle_tcb;
+
+std::array<StackType_t, configTIMER_TASK_STACK_DEPTH> freertos_timer_stack;
+StaticTask_t freertos_timer_tcb;
+
+std::array<char, configMAX_TASK_NAME_LEN> temp_thread_name_buffer;
+
+}  // namespace
+
+// Functions needed when configGENERATE_RUN_TIME_STATS is on.
+extern "C" void configureTimerForRunTimeStats(void) {}
+extern "C" unsigned long getRunTimeCounterValue(void) { return 10 /* FIXME */; }
+// uwTick is an uint32_t incremented each Systick interrupt 1ms. uwTick is used
+// to execute HAL_Delay function.
+
+// Required for configCHECK_FOR_STACK_OVERFLOW.
+extern "C" void vApplicationStackOverflowHook(TaskHandle_t, char* pcTaskName) {
+  pw::string::Copy(pcTaskName, temp_thread_name_buffer);
+  PW_CRASH("Stack OVF for task %s", temp_thread_name_buffer.data());
+}
+
+// Required for configUSE_TIMERS.
+extern "C" void vApplicationGetTimerTaskMemory(
+    StaticTask_t** ppxIdleTaskTCBBuffer,
+    StackType_t** ppxIdleTaskStackBuffer,
+    uint32_t* pulIdleTaskStackSize) {
+  *ppxIdleTaskTCBBuffer = &freertos_idle_tcb;
+  *ppxIdleTaskStackBuffer = freertos_idle_stack.data();
+  *pulIdleTaskStackSize = freertos_idle_stack.size();
+}
+
+extern "C" void vApplicationGetIdleTaskMemory(
+    StaticTask_t** ppxIdleTaskTCBBuffer,
+    StackType_t** ppxIdleTaskStackBuffer,
+    uint32_t* pulIdleTaskStackSize) {
+  *ppxIdleTaskTCBBuffer = &freertos_timer_tcb;
+  *ppxIdleTaskStackBuffer = freertos_timer_stack.data();
+  *pulIdleTaskStackSize = freertos_timer_stack.size();
+}
+
+extern "C" void pw_boot_PreStaticMemoryInit() {}
+
+extern "C" void pw_boot_PreStaticConstructorInit() {
+  // TODO(skeys) add "#if no_bootLoader" and the functions needed for init.
+
+#if PW_MALLOC_ACTIVE
+  pw_MallocInit(&pw_boot_heap_low_addr, &pw_boot_heap_high_addr);
+#endif  // PW_MALLOC_ACTIVE
+  pw_sys_io_Init();
+}
+
+// TODO(amontanez): pw_boot_PreMainInit() should get renamed to
+// pw_boot_FinalizeBoot or similar when main() is removed.
+extern "C" void pw_boot_PreMainInit() {
+  pw::system::Init();
+  vTaskStartScheduler();
+  PW_UNREACHABLE;
+}
+
+// This `main()` stub prevents another main function from being linked since
+// this target deliberately doesn't run `main()`.
+extern "C" int main() {}
+
+extern "C" PW_NO_RETURN void pw_boot_PostMain() {
+  // In case main() returns, just sit here until the device is reset.
+  while (true) {
+  }
+  PW_UNREACHABLE;
+}
diff --git a/targets/emcraft_sf2_som/config/FreeRTOSConfig.h b/targets/emcraft_sf2_som/config/FreeRTOSConfig.h
new file mode 100644
index 000000000..c024e3e60
--- /dev/null
+++ b/targets/emcraft_sf2_som/config/FreeRTOSConfig.h
@@ -0,0 +1,81 @@
+// Copyright 2022 The Pigweed Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations under
+// the License.
+#pragma once
+
+#include <stdint.h>
+
+// Externally defined variables that must be forward-declared for FreeRTOS to
+// use them.
+extern uint32_t SystemCoreClock;
+extern void configureTimerForRunTimeStats(void);
+extern unsigned long getRunTimeCounterValue(void);
+
+#define configSUPPORT_DYNAMIC_ALLOCATION 0
+#define configSUPPORT_STATIC_ALLOCATION 1
+
+#define configUSE_16_BIT_TICKS 0
+#define configUSE_CO_ROUTINES 0
+#define configUSE_IDLE_HOOK 0
+#define configUSE_MUTEXES 1
+#define configUSE_PORT_OPTIMISED_TASK_SELECTION 1
+#define configUSE_PREEMPTION 1
+#define configUSE_TICK_HOOK 0
+#define configUSE_TIMERS 1
+#define configUSE_TRACE_FACILITY 1
+
+#define configGENERATE_RUN_TIME_STATS 1
+#define portCONFIGURE_TIMER_FOR_RUN_TIME_STATS configureTimerForRunTimeStats
+#define portGET_RUN_TIME_COUNTER_VALUE getRunTimeCounterValue
+
+#define configCHECK_FOR_STACK_OVERFLOW 2
+#define configCPU_CLOCK_HZ (SystemCoreClock)
+#define configENABLE_BACKWARD_COMPATIBILITY 0
+#define configMAX_CO_ROUTINE_PRIORITIES (2)
+#define configMAX_PRIORITIES (7)
+#define configMAX_TASK_NAME_LEN (16)
+#define configMESSAGE_BUFFER_LENGTH_TYPE size_t
+#define configMINIMAL_STACK_SIZE ((uint16_t)128)
+#define configQUEUE_REGISTRY_SIZE 8
+#define configRECORD_STACK_HIGH_ADDRESS 1
+#define configTICK_RATE_HZ ((TickType_t)1000)
+#define configTIMER_QUEUE_LENGTH 10
+#define configTIMER_TASK_PRIORITY (6)
+#define configTIMER_TASK_STACK_DEPTH 512
+
+/* __NVIC_PRIO_BITS in CMSIS */
+#define configPRIO_BITS 4
+
+#define configLIBRARY_LOWEST_INTERRUPT_PRIORITY 15
+#define configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY 5
+#define configKERNEL_INTERRUPT_PRIORITY \
+  (configLIBRARY_LOWEST_INTERRUPT_PRIORITY << (8 - configPRIO_BITS))
+#define configMAX_SYSCALL_INTERRUPT_PRIORITY \
+  (configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY << (8 - configPRIO_BITS))
+
+#define INCLUDE_uxTaskPriorityGet 1
+#define INCLUDE_vTaskCleanUpResources 0
+#define INCLUDE_vTaskDelay 1
+#define INCLUDE_vTaskDelayUntil 0
+#define INCLUDE_vTaskDelete 1
+#define INCLUDE_vTaskPrioritySet 1
+#define INCLUDE_vTaskSuspend 1
+#define INCLUDE_xTaskGetSchedulerState 1
+
+// Instead of defining configASSERT(), include a header that provides a
+// definition that redirects to pw_assert.
+#include "pw_third_party/freertos/config_assert.h"
+
+#define vPortSVCHandler SVC_Handler
+#define xPortPendSVHandler PendSV_Handler
+#define xPortSysTickHandler SysTick_Handler
diff --git a/targets/emcraft_sf2_som/config/sf2_mss_hal_conf.h b/targets/emcraft_sf2_som/config/sf2_mss_hal_conf.h
new file mode 100644
index 000000000..2f16d2e40
--- /dev/null
+++ b/targets/emcraft_sf2_som/config/sf2_mss_hal_conf.h
@@ -0,0 +1,21 @@
+// Copyright 2022 The Pigweed Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations under
+// the License.
+
+#pragma once
+
+#define HAL_GPIO_MODULE_ENABLED
+#include "mss_gpio.h"
+
+#define HAL_UART_MODULE_ENABLED
+#include "mss_uart.h"
diff --git a/targets/emcraft_sf2_som/target_docs.rst b/targets/emcraft_sf2_som/target_docs.rst
new file mode 100644
index 000000000..adcc077e8
--- /dev/null
+++ b/targets/emcraft_sf2_som/target_docs.rst
@@ -0,0 +1,35 @@
+.. _target-emcraft-sf2-som:
+
+-------------------------------------
+_target-emcraft-sf2-som: SmartFusion2
+-------------------------------------
+The Emcraft SmartFusion2 system-on-module target configuration
+uses FreeRTOS and the Microchip MSS HAL rather than a from-the-ground-up
+baremetal approach.
+
+-----
+Setup
+-----
+To use this target, pigweed must be set up to use FreeRTOS and the Microchip
+MSS HAL for the SmartFusion series. The supported repositories can be
+downloaded via ``pw package``, and then the build must be manually configured
+to point to the locations the repositories were downloaded to.
+
+.. code:: sh
+
+  pw package install freertos
+  pw package install smartfusion_mss
+  pw package install nanopb
+
+  gn args out
+    # Add these lines, replacing ${PW_ROOT} with the path to the location that
+    # Pigweed is checked out at.
+    dir_pw_third_party_freertos = "${PW_ROOT}/.environment/packages/freertos"
+    dir_pw_third_party_smartfusion_mss =
+      "${PW_ROOT}/.environment/packages/smartfusion_mss"
+    dir_pw_third_party_nanopb = "${PW_ROOT}/.environment/packages/nanopb"
+
+Building and running the demo
+=============================
+This target does not yet build as part of Pigweed, but will later be
+available though the pw_system_demo build target.
diff --git a/targets/emcraft_sf2_som/vector_table.c b/targets/emcraft_sf2_som/vector_table.c
new file mode 100644
index 000000000..a4f5f7fc4
--- /dev/null
+++ b/targets/emcraft_sf2_som/vector_table.c
@@ -0,0 +1,75 @@
+// Copyright 2022 The Pigweed Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations under
+// the License.
+
+#include <stdbool.h>
+
+#include "pw_boot/boot.h"
+#include "pw_boot_cortex_m/boot.h"
+#include "pw_preprocessor/compiler.h"
+
+// Default handler to insert into the ARMv7-M vector table (below).
+// This function exists for convenience. If a device isn't doing what you
+// expect, it might have hit a fault and ended up here.
+static void DefaultFaultHandler(void) {
+  while (true) {
+    // Wait for debugger to attach.
+  }
+}
+
+// This is the device's interrupt vector table. It's not referenced in any
+// code because the platform (SmartFusion) expects this table to be present at
+// the beginning of flash. The exact address is specified in the pw_boot_armv7m
+// configuration as part of the target config.
+//
+// For more information, see ARMv7-M Architecture Reference Manual DDI 0403E.b
+// section B1.5.3.
+
+// This typedef is for convenience when building the vector table. With the
+// exception of SP_main (0th entry in the vector table), all the entries of the
+// vector table are function pointers.
+typedef void (*InterruptHandler)(void);
+
+// Interrupt handlers critical for OS operation.
+void SVC_Handler(void);
+void PendSV_Handler(void);
+void SysTick_Handler(void);
+
+PW_KEEP_IN_SECTION(".vector_table")
+const InterruptHandler vector_table[] = {
+    // The starting location of the stack pointer.
+    // This address is NOT an interrupt handler/function pointer, it is simply
+    // the address that the main stack pointer should be initialized to. The
+    // value is reinterpret casted because it needs to be in the vector table.
+    [0] = (InterruptHandler)(&pw_boot_stack_high_addr),
+
+    // Reset handler, dictates how to handle reset interrupt. This is the
+    // address that the Program Counter (PC) is initialized to at boot.
+    [1] = pw_boot_Entry,
+
+    // NMI handler.
+    [2] = DefaultFaultHandler,
+    // HardFault handler.
+    [3] = DefaultFaultHandler,
+    // 4-6: Specialized fault handlers.
+    // 7-10: Reserved.
+    // SVCall handler.
+    [11] = SVC_Handler,
+    // DebugMon handler.
+    [12] = DefaultFaultHandler,
+    // 13: Reserved.
+    // PendSV handler.
+    [14] = PendSV_Handler,
+    // SysTick handler.
+    [15] = SysTick_Handler,
+};