risc-v/sbi: add SRST extenstion usage in S-mode

This adds SBI specfication v0.3 based `riscv_sbi_system_reset()` to
support SBI firmware based system reset in kernel mode.

Signed-off-by: Yanfeng Liu <[email protected]>

Author: yf13

arch/Kconfig

@@ -92,6 +92,7 @@ config ARCH_RISCV
 	select ARCH_HAVE_RDWR_MEM_CPU_RUN
 	select ARCH_HAVE_TCBINFO
 	select ARCH_HAVE_THREAD_LOCAL
+	select ARCH_HAVE_POWEROFF
 	select ARCH_HAVE_LAZYFPU if ARCH_HAVE_FPU
 	---help---
 		RISC-V 32 and 64-bit RV32 / RV64 architectures.

arch/risc-v/src/common/riscv_internal.h

@@ -173,6 +173,7 @@
 #define SBI_EXT_HSM             0x48534D
 #define SBI_EXT_IPI             0x735049
 #define SBI_EXT_TIME            0x54494D45
+#define SBI_EXT_SRST            0x53525354
 
 /* SBI function IDs for TIME extension */
 
@@ -186,6 +187,21 @@
 
 #define SBI_EXT_IPI_SEND_IPI  0x0
 
+/* SBI function IDs for SRST extension */
+
+#define SBI_EXT_SRST_SYS_RESET 0x0
+
+/* SBI system reset type */
+
+#define SBI_SRST_TYPE_SHUTDOWN    0
+#define SBI_SRST_TYPE_REBOOT_COLD 1
+#define SBI_SRST_TYPE_REBOOT_WARM 1
+
+/* SBI system reset reason */
+
+#define SBI_SRST_REASON_NONE      0
+#define SBI_SRST_REASON_FAILURE   1
+
 /****************************************************************************
  * Public Types
  ****************************************************************************/
@@ -335,6 +351,7 @@ void riscv_sbi_set_timer(uint64_t stime_value);
 uint64_t riscv_sbi_get_time(void);
 uintptr_t riscv_sbi_boot_secondary(uint32_t hartid, uintptr_t addr,
                                    uintptr_t a1);
+uintptr_t riscv_sbi_system_reset(uint32_t type, uint32_t reason);
 #endif
 
 /* Power management *********************************************************/

arch/risc-v/src/common/supervisor/riscv_sbi.c

@@ -128,14 +128,20 @@ uint64_t riscv_sbi_get_time(void)
 uintptr_t riscv_sbi_send_ipi(uint32_t hmask, uintptr_t hbase)
 {
   return sbi_ecall(SBI_EXT_IPI, SBI_EXT_IPI_SEND_IPI,
-      hmask, hbase, 0, 0, 0, 0);
+                   hmask, hbase, 0, 0, 0, 0);
 }
 
 #ifndef CONFIG_NUTTSBI
+uintptr_t riscv_sbi_system_reset(uint32_t type, uint32_t reason)
+{
+  return sbi_ecall(SBI_EXT_SRST, SBI_EXT_SRST_SYS_RESET,
+                   type, reason, 0, 0, 0, 0);
+}
+
 uintptr_t riscv_sbi_boot_secondary(uint32_t hartid, uintptr_t addr,
                                    uintptr_t a1)
 {
   return sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_START,
-      hartid, addr, a1, 0, 0, 0);
+                   hartid, addr, a1, 0, 0, 0);
 }
 #endif /* CONFIG_NUTTSBI */