serial: earlycon-arm-semihost: Move smh_putc() variants in respective arch's semihost.h

Move smh_putc() variants in respective arch/*/include/asm/semihost.h,
in preparation to add RISC-V support.
Signed-off-by: Bin Meng <bmeng@tinylab.org>
Tested-by: Sergey Matyukevich <sergey.matyukevich@syntacore.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20221209150437.795918-2-bmeng@tinylab.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/arm/include/asm/semihost.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * Adapted for ARM and earlycon:
+ * Copyright (C) 2014 Linaro Ltd.
+ * Author: Rob Herring <robh@kernel.org>
+ */
+
+#ifndef _ARM_SEMIHOST_H_
+#define _ARM_SEMIHOST_H_
+
+#ifdef CONFIG_THUMB2_KERNEL
+#define SEMIHOST_SWI	"0xab"
+#else
+#define SEMIHOST_SWI	"0x123456"
+#endif
+
+struct uart_port;
+
+static inline void smh_putc(struct uart_port *port, unsigned char c)
+{
+	asm volatile("mov  r1, %0\n"
+		     "mov  r0, #3\n"
+		     "svc  " SEMIHOST_SWI "\n"
+		     : : "r" (&c) : "r0", "r1", "memory");
+}
+
+#endif /* _ARM_SEMIHOST_H_ */

arch/arm64/include/asm/semihost.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * Adapted for ARM and earlycon:
+ * Copyright (C) 2014 Linaro Ltd.
+ * Author: Rob Herring <robh@kernel.org>
+ */
+
+#ifndef _ARM64_SEMIHOST_H_
+#define _ARM64_SEMIHOST_H_
+
+struct uart_port;
+
+static inline void smh_putc(struct uart_port *port, unsigned char c)
+{
+	asm volatile("mov  x1, %0\n"
+		     "mov  x0, #3\n"
+		     "hlt  0xf000\n"
+		     : : "r" (&c) : "x0", "x1", "memory");
+}
+
+#endif /* _ARM64_SEMIHOST_H_ */

drivers/tty/serial/earlycon-arm-semihost.c

@@ -11,30 +11,7 @@
 #include <linux/console.h>
 #include <linux/init.h>
 #include <linux/serial_core.h>
-
-#ifdef CONFIG_THUMB2_KERNEL
-#define SEMIHOST_SWI	"0xab"
-#else
-#define SEMIHOST_SWI	"0x123456"
-#endif
-
-/*
- * Semihosting-based debug console
- */
-static void smh_putc(struct uart_port *port, unsigned char c)
-{
-#ifdef CONFIG_ARM64
-	asm volatile("mov  x1, %0\n"
-		     "mov  x0, #3\n"
-		     "hlt  0xf000\n"
-		     : : "r" (&c) : "x0", "x1", "memory");
-#else
-	asm volatile("mov  r1, %0\n"
-		     "mov  r0, #3\n"
-		     "svc  " SEMIHOST_SWI "\n"
-		     : : "r" (&c) : "r0", "r1", "memory");
-#endif
-}
+#include <asm/semihost.h>
 
 static void smh_write(struct console *con, const char *s, unsigned n)
 {