MIPS: qemu-malta: add reset support

The MIPS Malta board has a SOFTRES register. Writing a
magic value into that register initiates a board reset.

Use this feature to implement reset support.
Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Cc: Daniel Schwierzeck <daniel.schwierzeck@googlemail.com>

arch/mips/include/asm/malta.h

@@ -13,4 +13,7 @@
 
 #define MALTA_UART_BASE		(MALTA_IO_PORT_BASE + 0x3f8)
 
+#define MALTA_RESET_BASE	0x1f000500
+#define GORESET			0x42
+
 #endif /* _MIPS_ASM_MALTA_H */

board/qemu-malta/qemu-malta.c

@@ -8,6 +8,9 @@
 
 #include <common.h>
 
+#include <asm/io.h>
+#include <asm/malta.h>
+
 phys_size_t initdram(int board_type)
 {
 	return CONFIG_SYS_MEM_SIZE;
@@ -18,3 +21,11 @@ int checkboard(void)
 	puts("Board: MIPS Malta CoreLV (Qemu)\n");
 	return 0;
 }
+
+void _machine_restart(void)
+{
+	void __iomem *reset_base;
+
+	reset_base = (void __iomem *)CKSEG1ADDR(MALTA_RESET_BASE);
+	__raw_writel(GORESET, reset_base);
+}