80 lines
2 KiB
C
80 lines
2 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* 16550 serial console support.
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*
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* Original copied from <file:arch/ppc/boot/common/ns16550.c>
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* (which had no copyright)
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* Modifications: 2006 (c) MontaVista Software, Inc.
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*
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* Modified by: Mark A. Greer <mgreer@mvista.com>
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*/
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#include <stdarg.h>
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#include <stddef.h>
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#include "types.h"
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#include "string.h"
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#include "stdio.h"
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#include "io.h"
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#include "ops.h"
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#define UART_DLL 0 /* Out: Divisor Latch Low */
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#define UART_DLM 1 /* Out: Divisor Latch High */
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#define UART_FCR 2 /* Out: FIFO Control Register */
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#define UART_LCR 3 /* Out: Line Control Register */
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#define UART_MCR 4 /* Out: Modem Control Register */
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#define UART_LSR 5 /* In: Line Status Register */
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#define UART_LSR_THRE 0x20 /* Transmit-hold-register empty */
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#define UART_LSR_DR 0x01 /* Receiver data ready */
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#define UART_MSR 6 /* In: Modem Status Register */
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#define UART_SCR 7 /* I/O: Scratch Register */
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static unsigned char *reg_base;
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static u32 reg_shift;
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static int ns16550_open(void)
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{
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out_8(reg_base + (UART_FCR << reg_shift), 0x06);
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return 0;
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}
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static void ns16550_putc(unsigned char c)
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{
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while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_THRE) == 0);
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out_8(reg_base, c);
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}
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static unsigned char ns16550_getc(void)
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{
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while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) == 0);
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return in_8(reg_base);
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}
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static u8 ns16550_tstc(void)
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{
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return ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) != 0);
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}
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int ns16550_console_init(void *devp, struct serial_console_data *scdp)
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{
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int n;
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u32 reg_offset;
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if (dt_get_virtual_reg(devp, (void **)®_base, 1) < 1)
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return -1;
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n = getprop(devp, "reg-offset", ®_offset, sizeof(reg_offset));
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if (n == sizeof(reg_offset))
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reg_base += reg_offset;
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n = getprop(devp, "reg-shift", ®_shift, sizeof(reg_shift));
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if (n != sizeof(reg_shift))
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reg_shift = 0;
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scdp->open = ns16550_open;
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scdp->putc = ns16550_putc;
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scdp->getc = ns16550_getc;
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scdp->tstc = ns16550_tstc;
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scdp->close = NULL;
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return 0;
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}
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