cregit-Linux how code gets into the kernel

Release 4.14 arch/mips/kernel/early_printk_8250.c

Directory: arch/mips/kernel
/*
 *  8250/16550-type serial ports prom_putchar()
 *
 *  Copyright (C) 2010  Yoichi Yuasa <yuasa@linux-mips.org>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
#include <linux/io.h>
#include <linux/serial_core.h>
#include <linux/serial_reg.h>


static void __iomem *serial8250_base;

static unsigned int serial8250_reg_shift;

static unsigned int serial8250_tx_timeout;


void setup_8250_early_printk_port(unsigned long base, unsigned int reg_shift, unsigned int timeout) { serial8250_base = (void __iomem *)base; serial8250_reg_shift = reg_shift; serial8250_tx_timeout = timeout; }

Contributors

PersonTokensPropCommitsCommitProp
Yoichi Yuasa34100.00%1100.00%
Total34100.00%1100.00%


static inline u8 serial_in(int offset) { return readb(serial8250_base + (offset << serial8250_reg_shift)); }

Contributors

PersonTokensPropCommitsCommitProp
Yoichi Yuasa22100.00%1100.00%
Total22100.00%1100.00%


static inline void serial_out(int offset, char value) { writeb(value, serial8250_base + (offset << serial8250_reg_shift)); }

Contributors

PersonTokensPropCommitsCommitProp
Yoichi Yuasa26100.00%1100.00%
Total26100.00%1100.00%


void prom_putchar(char c) { unsigned int timeout; int status, bits; if (!serial8250_base) return; timeout = serial8250_tx_timeout; bits = UART_LSR_TEMT | UART_LSR_THRE; do { status = serial_in(UART_LSR); if (--timeout == 0) break; } while ((status & bits) != bits); if (timeout) serial_out(UART_TX, c); }

Contributors

PersonTokensPropCommitsCommitProp
Yoichi Yuasa73100.00%1100.00%
Total73100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Yoichi Yuasa181100.00%1100.00%
Total181100.00%1100.00%
Directory: arch/mips/kernel
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