1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Each architecture must implement puts() and exit() with the I/O 4 * devices exposed from QEMU, e.g. ns16550a. 5 * 6 * Copyright (C) 2023, Ventana Micro Systems Inc., Andrew Jones <ajones@ventanamicro.com> 7 */ 8 #include <libcflat.h> 9 #include <config.h> 10 #include <devicetree.h> 11 #include <asm/io.h> 12 #include <asm/setup.h> 13 #include <asm/spinlock.h> 14 15 /* 16 * Use this guess for the uart base in order to make an attempt at 17 * having earlier printf support. We'll overwrite it with the real 18 * base address that we read from the device tree later. This is 19 * the address we expect the virtual machine manager to put in 20 * its generated device tree. 21 */ 22 #define UART_EARLY_BASE ((u8 *)(unsigned long)CONFIG_UART_EARLY_BASE) 23 static volatile u8 *uart0_base = UART_EARLY_BASE; 24 static struct spinlock uart_lock; 25 26 static void uart0_init_fdt(void) 27 { 28 const char *compatible[] = {"ns16550a"}; 29 struct dt_pbus_reg base; 30 int i, ret; 31 32 ret = dt_get_default_console_node(); 33 assert(ret >= 0 || ret == -FDT_ERR_NOTFOUND); 34 35 if (ret == -FDT_ERR_NOTFOUND) { 36 for (i = 0; i < ARRAY_SIZE(compatible); i++) { 37 ret = dt_pbus_get_base_compatible(compatible[i], &base); 38 assert(ret == 0 || ret == -FDT_ERR_NOTFOUND); 39 if (ret == 0) 40 break; 41 } 42 43 if (ret) { 44 printf("%s: Compatible uart not found in the device tree, aborting...\n", 45 __func__); 46 abort(); 47 } 48 } else { 49 ret = dt_pbus_translate_node(ret, 0, &base); 50 assert(ret == 0); 51 } 52 53 uart0_base = ioremap(base.addr, base.size); 54 } 55 56 static void uart0_init_acpi(void) 57 { 58 assert_msg(false, "ACPI not available"); 59 } 60 61 void io_init(void) 62 { 63 if (dt_available()) 64 uart0_init_fdt(); 65 else 66 uart0_init_acpi(); 67 68 if (uart0_base != UART_EARLY_BASE) { 69 printf("WARNING: early print support may not work. " 70 "Found uart at %p, but early base is %p.\n", 71 uart0_base, UART_EARLY_BASE); 72 } 73 } 74 75 void puts(const char *s) 76 { 77 spin_lock(&uart_lock); 78 while (*s) 79 writeb(*s++, uart0_base); 80 spin_unlock(&uart_lock); 81 } 82 83 /* 84 * Defining halt to take 'code' as an argument guarantees that it will 85 * be in a0 when we halt. That gives us a final chance to see the exit 86 * status while inspecting the halted unit test state. 87 */ 88 void halt(int code); 89 90 void exit(int code) 91 { 92 printf("\nEXIT: STATUS=%d\n", ((code) << 1) | 1); 93 halt(code); 94 __builtin_unreachable(); 95 } 96