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