lib: sbi: Improve system reset platform operations

To implement the SBI SRST extension, we need two platform operations
for system reset:
1) system_reset_check() - This operation will check whether given
   reset type and reason are supported by the platform
2) system_reset() - This operation will do the actual platform
   system reset and it will not return if reset type and reason
   are supported by the platform

This patch updates system reset related code everywhere as-per above.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

lib/sbi/sbi_ecall_legacy.c

@@ -103,7 +103,8 @@ static int sbi_ecall_legacy_handler(unsigned long extid, unsigned long funcid,
 		}
 		break;
 	case SBI_EXT_0_1_SHUTDOWN:
-		sbi_system_reset(SBI_SRST_RESET_TYPE_SHUTDOWN);
+		sbi_system_reset(SBI_SRST_RESET_TYPE_SHUTDOWN,
+				 SBI_SRST_RESET_REASON_NONE);
 		break;
 	default:
 		ret = SBI_ENOTSUPP;

lib/sbi/sbi_system.c

@@ -18,7 +18,16 @@
 #include <sbi/sbi_ipi.h>
 #include <sbi/sbi_init.h>
 
-void __noreturn sbi_system_reset(u32 reset_type)
+bool sbi_system_reset_supported(u32 reset_type, u32 reset_reason)
+{
+	if (sbi_platform_system_reset_check(sbi_platform_thishart_ptr(),
+					    reset_type, reset_reason))
+		return TRUE;
+
+	return FALSE;
+}
+
+void __noreturn sbi_system_reset(u32 reset_type, u32 reset_reason)
 {
 	ulong hbase = 0, hmask;
 	u32 cur_hartid = current_hartid();
@@ -40,7 +49,7 @@ void __noreturn sbi_system_reset(u32 reset_type)
 	/* Platform specific reset if domain allowed system reset */
 	if (dom->system_reset_allowed)
 		sbi_platform_system_reset(sbi_platform_ptr(scratch),
-					  reset_type);
+					  reset_type, reset_reason);
 
 	/* If platform specific reset did not work then do sbi_exit() */
 	sbi_exit(scratch);

lib/utils/reset/fdt_reset.c

@@ -21,11 +21,18 @@ static struct fdt_reset *reset_drivers[] = {
 
 static struct fdt_reset *current_driver = NULL;
 
-int fdt_system_reset(u32 reset_type)
+int fdt_system_reset_check(u32 reset_type, u32 reset_reason)
+{
+	if (current_driver && current_driver->system_reset_check)
+		return current_driver->system_reset_check(reset_type,
+							  reset_reason);
+	return 0;
+}
+
+void fdt_system_reset(u32 reset_type, u32 reset_reason)
 {
 	if (current_driver && current_driver->system_reset)
-		return current_driver->system_reset(reset_type);
-	return 0;
+		current_driver->system_reset(reset_type, reset_reason);
 }
 
 int fdt_reset_init(void)

lib/utils/reset/fdt_reset_htif.c

@@ -18,5 +18,6 @@ static const struct fdt_match htif_reset_match[] = {
 
 struct fdt_reset fdt_reset_htif = {
 	.match_table = htif_reset_match,
+	.system_reset_check = htif_system_reset_check,
 	.system_reset = htif_system_reset
 };

lib/utils/reset/fdt_reset_sifive.c

@@ -33,5 +33,6 @@ static const struct fdt_match sifive_test_reset_match[] = {
 struct fdt_reset fdt_reset_sifive = {
 	.match_table = sifive_test_reset_match,
 	.init = sifive_test_reset_init,
+	.system_reset_check = sifive_test_system_reset_check,
 	.system_reset = sifive_test_system_reset
 };

lib/utils/sys/htif.c

@@ -140,7 +140,12 @@ int htif_getc(void)
 	return ch - 1;
 }
 
-int htif_system_reset(u32 type)
+int htif_system_reset_check(u32 type, u32 reason)
+{
+	return 1;
+}
+
+void htif_system_reset(u32 type, u32 reason)
 {
 	while (1) {
 		fromhost = 0;

lib/utils/sys/sifive_test.c

@@ -8,7 +8,7 @@
  */
 
 #include <sbi/riscv_io.h>
-#include <sbi/sbi_platform.h>
+#include <sbi/sbi_ecall_interface.h>
 #include <sbi_utils/sys/sifive_test.h>
 
 #define FINISHER_FAIL		0x3333
@@ -17,7 +17,19 @@
 
 static void *sifive_test_base;
 
-int sifive_test_system_reset(u32 type)
+int sifive_test_system_reset_check(u32 type, u32 reason)
+{
+	switch (type) {
+	case SBI_SRST_RESET_TYPE_SHUTDOWN:
+	case SBI_SRST_RESET_TYPE_COLD_REBOOT:
+	case SBI_SRST_RESET_TYPE_WARM_REBOOT:
+		return 1;
+	}
+
+	return 0;
+}
+
+void sifive_test_system_reset(u32 type, u32 reason)
 {
 	/*
 	 * Tell the "finisher" that the simulation
@@ -25,15 +37,16 @@ int sifive_test_system_reset(u32 type)
 	 */
 	switch (type) {
 	case SBI_SRST_RESET_TYPE_SHUTDOWN:
-		writew(FINISHER_PASS, sifive_test_base);
+		if (reason == SBI_SRST_RESET_REASON_NONE)
+			writew(FINISHER_PASS, sifive_test_base);
+		else
+			writew(FINISHER_FAIL, sifive_test_base);
 		break;
 	case SBI_SRST_RESET_TYPE_COLD_REBOOT:
 	case SBI_SRST_RESET_TYPE_WARM_REBOOT:
 		writew(FINISHER_RESET, sifive_test_base);
 		break;
 	}
-
-	return 0;
 }
 
 int sifive_test_init(unsigned long base)