1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * 16550 serial console support. 4 * 5 * Original copied from <file:arch/ppc/boot/common/ns16550.c> 6 * (which had no copyright) 7 * Modifications: 2006 (c) MontaVista Software, Inc. 8 * 9 * Modified by: Mark A. Greer <mgreer@mvista.com> 10 */ 11 #include <stdarg.h> 12 #include <stddef.h> 13 #include "types.h" 14 #include "string.h" 15 #include "stdio.h" 16 #include "io.h" 17 #include "ops.h" 18 #include "of.h" 19 20 #define UART_DLL 0 /* Out: Divisor Latch Low */ 21 #define UART_DLM 1 /* Out: Divisor Latch High */ 22 #define UART_FCR 2 /* Out: FIFO Control Register */ 23 #define UART_LCR 3 /* Out: Line Control Register */ 24 #define UART_MCR 4 /* Out: Modem Control Register */ 25 #define UART_LSR 5 /* In: Line Status Register */ 26 #define UART_LSR_THRE 0x20 /* Transmit-hold-register empty */ 27 #define UART_LSR_DR 0x01 /* Receiver data ready */ 28 #define UART_MSR 6 /* In: Modem Status Register */ 29 #define UART_SCR 7 /* I/O: Scratch Register */ 30 31 static unsigned char *reg_base; 32 static u32 reg_shift; 33 34 static int ns16550_open(void) 35 { 36 out_8(reg_base + (UART_FCR << reg_shift), 0x06); 37 return 0; 38 } 39 40 static void ns16550_putc(unsigned char c) 41 { 42 while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_THRE) == 0); 43 out_8(reg_base, c); 44 } 45 46 static unsigned char ns16550_getc(void) 47 { 48 while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) == 0); 49 return in_8(reg_base); 50 } 51 52 static u8 ns16550_tstc(void) 53 { 54 return ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) != 0); 55 } 56 57 int ns16550_console_init(void *devp, struct serial_console_data *scdp) 58 { 59 int n; 60 u32 reg_offset; 61 62 if (dt_get_virtual_reg(devp, (void **)®_base, 1) < 1) { 63 printf("virt reg parse fail...\r\n"); 64 return -1; 65 } 66 67 n = getprop(devp, "reg-offset", ®_offset, sizeof(reg_offset)); 68 if (n == sizeof(reg_offset)) 69 reg_base += be32_to_cpu(reg_offset); 70 71 n = getprop(devp, "reg-shift", ®_shift, sizeof(reg_shift)); 72 if (n != sizeof(reg_shift)) 73 reg_shift = 0; 74 else 75 reg_shift = be32_to_cpu(reg_shift); 76 77 scdp->open = ns16550_open; 78 scdp->putc = ns16550_putc; 79 scdp->getc = ns16550_getc; 80 scdp->tstc = ns16550_tstc; 81 scdp->close = NULL; 82 83 return 0; 84 } 85