xtensa: extract common CPU reset code into separate function

platform_restart implementatations do the same thing to reset CPU.
Don't duplicate that code, move it to a function and call it from
platform_restart.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/include/asm/platform.h

@@ -69,4 +69,10 @@ extern int platform_pcibios_fixup (void);
  */
 extern void platform_calibrate_ccount (void);
 
+/*
+ * Flush and reset the mmu, simulate a processor reset, and
+ * jump to the reset vector.
+ */
+void cpu_reset(void) __attribute__((noreturn));
+
 #endif	/* _XTENSA_PLATFORM_H */

arch/xtensa/kernel/setup.c

@@ -549,6 +549,29 @@ static int __init topology_init(void)
 }
 subsys_initcall(topology_init);
 
+void cpu_reset(void)
+{
+	__asm__ __volatile__ ("movi	a2, 15\n\t"
+			      "wsr	a2, icountlevel\n\t"
+			      "movi	a2, 0\n\t"
+			      "wsr	a2, icount\n\t"
+#if XCHAL_NUM_IBREAK > 0
+			      "wsr	a2, ibreakenable\n\t"
+#endif
+#if XCHAL_HAVE_LOOPS
+			      "wsr	a2, lcount\n\t"
+#endif
+			      "movi	a2, 0x1f\n\t"
+			      "wsr	a2, ps\n\t"
+			      "isync\n\t"
+			      "jx	%0\n\t"
+			      :
+			      : "a" (XCHAL_RESET_VECTOR_VADDR)
+			      : "a2");
+	for (;;)
+		;
+}
+
 void machine_restart(char * cmd)
 {
 	platform_restart();

arch/xtensa/platforms/iss/setup.c

@@ -53,25 +53,7 @@ void platform_restart(void)
 {
 	/* Flush and reset the mmu, simulate a processor reset, and
 	 * jump to the reset vector. */
-
-	__asm__ __volatile__("movi	a2, 15\n\t"
-			     "wsr	a2, icountlevel\n\t"
-			     "movi	a2, 0\n\t"
-			     "wsr	a2, icount\n\t"
-#if XCHAL_NUM_IBREAK > 0
-			     "wsr	a2, ibreakenable\n\t"
-#endif
-#if XCHAL_HAVE_LOOPS
-			     "wsr	a2, lcount\n\t"
-#endif
-			     "movi	a2, 0x1f\n\t"
-			     "wsr	a2, ps\n\t"
-			     "isync\n\t"
-			     "jx	%0\n\t"
-			     :
-			     : "a" (XCHAL_RESET_VECTOR_VADDR)
-			     : "a2");
-
+	cpu_reset();
 	/* control never gets here */
 }
 

arch/xtensa/platforms/xt2000/setup.c

@@ -64,26 +64,7 @@ void platform_restart(void)
 {
 	/* Flush and reset the mmu, simulate a processor reset, and
 	 * jump to the reset vector. */
-
-	__asm__ __volatile__ ("movi	a2, 15\n\t"
-			      "wsr	a2, icountlevel\n\t"
-			      "movi	a2, 0\n\t"
-			      "wsr	a2, icount\n\t"
-#if XCHAL_NUM_IBREAK > 0
-			      "wsr	a2, ibreakenable\n\t"
-#endif
-#if XCHAL_HAVE_LOOPS
-			      "wsr	a2, lcount\n\t"
-#endif
-			      "movi	a2, 0x1f\n\t"
-			      "wsr	a2, ps\n\t"
-			      "isync\n\t"
-			      "jx	%0\n\t"
-			      :
-			      : "a" (XCHAL_RESET_VECTOR_VADDR)
-			      : "a2"
-			      );
-
+	cpu_reset();
 	/* control never gets here */
 }
 

arch/xtensa/platforms/xtfpga/setup.c

@@ -54,27 +54,7 @@ void platform_restart(void)
 {
 	/* Flush and reset the mmu, simulate a processor reset, and
 	 * jump to the reset vector. */
-
-
-	__asm__ __volatile__ ("movi	a2, 15\n\t"
-			      "wsr	a2, icountlevel\n\t"
-			      "movi	a2, 0\n\t"
-			      "wsr	a2, icount\n\t"
-#if XCHAL_NUM_IBREAK > 0
-			      "wsr	a2, ibreakenable\n\t"
-#endif
-#if XCHAL_HAVE_LOOPS
-			      "wsr	a2, lcount\n\t"
-#endif
-			      "movi	a2, 0x1f\n\t"
-			      "wsr	a2, ps\n\t"
-			      "isync\n\t"
-			      "jx	%0\n\t"
-			      :
-			      : "a" (XCHAL_RESET_VECTOR_VADDR)
-			      : "a2"
-			      );
-
+	cpu_reset();
 	/* control never gets here */
 }