linux-kernel - [PATCH v3 1/3] serial: earlycon-arm-semihost: Move smh_putc() variants in respective arch's semihost.h

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Message-Id: <20221209150437.795918-2-bmeng@tinylab.org>
Date:   Fri,  9 Dec 2022 23:04:35 +0800
From:   Bin Meng <bmeng@...ylab.org>
To:     linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org,
        linux-serial@...r.kernel.org
Cc:     Catalin Marinas <catalin.marinas@....com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jirislaby@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        Will Deacon <will@...nel.org>,
        linux-arm-kernel@...ts.infradead.org
Subject: [PATCH v3 1/3] 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@...ylab.org>

---

Changes in v3:
- add #ifdef in the header to prevent from multiple inclusion
- add forward-declare struct uart_port

Changes in v2:
- new patch: "serial: earlycon-arm-semihost: Move smh_putc() variants in respective arch's semihost.h"

 arch/arm/include/asm/semihost.h            | 30 ++++++++++++++++++++++
 arch/arm64/include/asm/semihost.h          | 24 +++++++++++++++++
 drivers/tty/serial/earlycon-arm-semihost.c | 25 +-----------------
 3 files changed, 55 insertions(+), 24 deletions(-)
 create mode 100644 arch/arm/include/asm/semihost.h
 create mode 100644 arch/arm64/include/asm/semihost.h

diff --git a/arch/arm/include/asm/semihost.h b/arch/arm/include/asm/semihost.h
new file mode 100644
index 000000000000..f365787e7c23
--- /dev/null
+++ b/arch/arm/include/asm/semihost.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ * Author: Marc Zyngier <marc.zyngier@....com>
+ *
+ * Adapted for ARM and earlycon:
+ * Copyright (C) 2014 Linaro Ltd.
+ * Author: Rob Herring <robh@...nel.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_ */
diff --git a/arch/arm64/include/asm/semihost.h b/arch/arm64/include/asm/semihost.h
new file mode 100644
index 000000000000..87e353dab868
--- /dev/null
+++ b/arch/arm64/include/asm/semihost.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ * Author: Marc Zyngier <marc.zyngier@....com>
+ *
+ * Adapted for ARM and earlycon:
+ * Copyright (C) 2014 Linaro Ltd.
+ * Author: Rob Herring <robh@...nel.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_ */
diff --git a/drivers/tty/serial/earlycon-arm-semihost.c b/drivers/tty/serial/earlycon-arm-semihost.c
index fcdec5f42376..e4692a8433f9 100644
--- a/drivers/tty/serial/earlycon-arm-semihost.c
+++ b/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)
 {
-- 
2.34.1