arch/arm/include/asm/semihost.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (C) 2012 ARM Ltd.
   4  * Author: Marc Zyngier <marc.zyngier@arm.com>
   5  *
   6  * Adapted for ARM and earlycon:
   7  * Copyright (C) 2014 Linaro Ltd.
   8  * Author: Rob Herring <robh@kernel.org>
   9  */
  10
  11 #ifndef _ARM_SEMIHOST_H_
  12 #define _ARM_SEMIHOST_H_
  13
  14 #ifdef CONFIG_THUMB2_KERNEL
  15 #define SEMIHOST_SWI    "0xab"
  16 #else
  17 #define SEMIHOST_SWI    "0x123456"
  18 #endif
  19
  20 struct uart_port;
  21
  22 static inline void smh_putc(struct uart_port *port, unsigned char c)
  23 {
  24         asm volatile("mov  r1, %0\n"
  25                      "mov  r0, #3\n"
  26                      "svc  " SEMIHOST_SWI "\n"
  27                      : : "r" (&c) : "r0", "r1", "memory");
  28 }
  29
  30 #endif /* _ARM_SEMIHOST_H_ */