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/sbi.h> 13 #include <asm/setup.h> 14 #include <asm/spinlock.h> 15 16 #define UART_LSR_OFFSET 5 17 #define UART_LSR_THRE 0x20 18 19 /* 20 * Use this guess for the uart base in order to make an attempt at 21 * having earlier printf support. We'll overwrite it with the real 22 * base address that we read from the device tree later. This is 23 * the address we expect the virtual machine manager to put in 24 * its generated device tree. 25 */ 26 #define UART_EARLY_BASE ((u8 *)(unsigned long)CONFIG_UART_EARLY_BASE) 27 static volatile u8 *uart0_base = UART_EARLY_BASE; 28 static struct spinlock uart_lock; 29 30 static void uart0_init_fdt(void) 31 { 32 const char *compatible[] = {"ns16550a"}; 33 struct dt_pbus_reg base; 34 int i, ret; 35 36 ret = dt_get_default_console_node(); 37 assert(ret >= 0 || ret == -FDT_ERR_NOTFOUND); 38 39 if (ret == -FDT_ERR_NOTFOUND) { 40 for (i = 0; i < ARRAY_SIZE(compatible); i++) { 41 ret = dt_pbus_get_base_compatible(compatible[i], &base); 42 assert(ret == 0 || ret == -FDT_ERR_NOTFOUND); 43 if (ret == 0) 44 break; 45 } 46 47 if (ret) { 48 printf("%s: Compatible uart not found in the device tree, aborting...\n", 49 __func__); 50 abort(); 51 } 52 } else { 53 ret = dt_pbus_translate_node(ret, 0, &base); 54 assert(ret == 0); 55 } 56 57 uart0_base = ioremap(base.addr, base.size); 58 } 59 60 static void uart0_init_acpi(void) 61 { 62 assert_msg(false, "ACPI not available"); 63 } 64 65 void io_init(void) 66 { 67 if (dt_available()) 68 uart0_init_fdt(); 69 else 70 uart0_init_acpi(); 71 72 if (uart0_base != UART_EARLY_BASE) { 73 printf("WARNING: early print support may not work. " 74 "Found uart at %p, but early base is %p.\n", 75 uart0_base, UART_EARLY_BASE); 76 } 77 } 78 79 void puts(const char *s) 80 { 81 spin_lock(&uart_lock); 82 while (*s) { 83 while (!(readb(uart0_base + UART_LSR_OFFSET) & UART_LSR_THRE)) 84 ; 85 writeb(*s++, uart0_base); 86 } 87 spin_unlock(&uart_lock); 88 } 89 90 /* 91 * Defining halt to take 'code' as an argument guarantees that it will 92 * be in a0 when we halt. That gives us a final chance to see the exit 93 * status while inspecting the halted unit test state. 94 */ 95 void halt(int code); 96 97 void exit(int code) 98 { 99 printf("\nEXIT: STATUS=%d\n", ((code) << 1) | 1); 100 sbi_shutdown(); 101 halt(code); 102 __builtin_unreachable(); 103 } 104