1 /* 2 * Copyright (c) 2019 LuoZhongYao 3 * SPDX-License-Identifier: Apache-2.0 4 */ 5 6 #include <kernel.h> 7 #include <device.h> 8 #include <init.h> 9 10 extern void __stdout_hook_install(int (*fn)(int)); 11 12 #define SYS_WRITEC 0x03 13 arch_printk_char_out(int _c)14int arch_printk_char_out(int _c) 15 { 16 char c = _c; 17 18 #if defined(CONFIG_CPU_CORTEX_M) 19 20 register unsigned long r0 __asm__("r0") = SYS_WRITEC; 21 register void *r1 __asm__("r1") = &c; 22 23 __asm__ __volatile__ ("bkpt 0xab" : : "r" (r0), "r" (r1) : "memory"); 24 25 #elif defined(CONFIG_ARM64) 26 27 register unsigned long x0 __asm__("x0") = SYS_WRITEC; 28 register void *x1 __asm__("x1") = &c; 29 30 __asm__ volatile ("hlt 0xf000" : : "r" (x0), "r" (x1) : "memory"); 31 32 #else 33 #error "unsupported CPU type" 34 #endif 35 36 return 0; 37 } 38 semihost_console_init(const struct device * dev)39static int semihost_console_init(const struct device *dev) 40 { 41 ARG_UNUSED(dev); 42 43 /* 44 * The printk output callback is arch_printk_char_out by default and 45 * is installed at link time. That makes printk() usable very early. 46 * 47 * We still need to install the stdout callback manually at run time. 48 */ 49 __stdout_hook_install(arch_printk_char_out); 50 51 return 0; 52 } 53 54 SYS_INIT(semihost_console_init, PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT); 55
