Add full automotive RTOS project

Add kernel (Cortex-M0/M3/M4, Tricore, S32K, RISC-V ports), drivers,
middleware (CAN stack, diagnostics, safety), applications, board
support, build/test tooling, and documentation.

kernel/arch/riscv/rv32/portmacro.h

@@ -0,0 +1,39 @@
+/**
+ * @file portmacro.h
+ * @brief RISC-V RV32 specific macros
+ */
+
+#ifndef PORTMACRO_H
+#define PORTMACRO_H
+
+#include <stdint.h>
+
+/* Data Types */
+typedef uint32_t port_stack_type_t;
+typedef uint32_t port_base_type_t;
+
+/* Architecture Constants */
+#define PORT_STACK_GROWTH_DIRECTION    (-1)
+#define PORT_BYTE_ALIGNMENT            16
+
+/* Critical Section Macros */
+#define portENTER_CRITICAL()    __asm volatile("csrci mstatus, 0x8")
+#define portEXIT_CRITICAL()     __asm volatile("csrsi mstatus, 0x8")
+
+/* Interrupt Control */
+#define portENABLE_INTERRUPTS()  __asm volatile("csrsi mstatus, 0x8")
+#define portDISABLE_INTERRUPTS() __asm volatile("csrci mstatus, 0x8")
+
+/* Context Switch */
+#define portYIELD()             __asm volatile("li t0, 0x8\ncsrs mip, t0")
+#define portYIELD_FROM_ISR()    __asm volatile("li t0, 0x8\ncsrs mip, t0")
+
+/* Memory Barriers */
+#define portMEMORY_BARRIER()    __asm volatile("fence")
+#define portSYNC_BARRIER()      __asm volatile("fence")
+#define portINSTRUCTION_BARRIER() __asm volatile("fence.i")
+
+/* NOP */
+#define portNOP()               __asm volatile("nop")
+
+#endif /* PORTMACRO_H */