110 lines
2.5 KiB
C
110 lines
2.5 KiB
C
/*
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* Early printk support for Microblaze.
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*
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* Copyright (C) 2007-2009 Michal Simek <monstr@monstr.eu>
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* Copyright (C) 2007-2009 PetaLogix
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* Copyright (C) 2003-2006 Yasushi SHOJI <yashi@atmark-techno.com>
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/console.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/string.h>
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#include <linux/tty.h>
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#include <linux/io.h>
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#include <asm/processor.h>
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#include <linux/fcntl.h>
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#include <asm/setup.h>
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#include <asm/prom.h>
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static u32 early_console_initialized;
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static u32 base_addr;
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static void early_printk_putc(char c)
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{
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/*
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* Limit how many times we'll spin waiting for TX FIFO status.
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* This will prevent lockups if the base address is incorrectly
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* set, or any other issue on the UARTLITE.
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* This limit is pretty arbitrary, unless we are at about 10 baud
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* we'll never timeout on a working UART.
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*/
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unsigned retries = 10000;
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/* read status bit - 0x8 offset */
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while (--retries && (in_be32(base_addr + 8) & (1 << 3)))
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;
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/* Only attempt the iowrite if we didn't timeout */
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/* write to TX_FIFO - 0x4 offset */
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if (retries)
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out_be32(base_addr + 4, c & 0xff);
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}
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static void early_printk_write(struct console *unused,
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const char *s, unsigned n)
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{
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while (*s && n-- > 0) {
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early_printk_putc(*s);
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if (*s == '\n')
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early_printk_putc('\r');
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s++;
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}
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}
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static struct console early_serial_console = {
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.name = "earlyser",
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.write = early_printk_write,
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.flags = CON_PRINTBUFFER,
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.index = -1,
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};
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static struct console *early_console = &early_serial_console;
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void early_printk(const char *fmt, ...)
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{
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char buf[512];
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int n;
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va_list ap;
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if (early_console_initialized) {
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va_start(ap, fmt);
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n = vscnprintf(buf, 512, fmt, ap);
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early_console->write(early_console, buf, n);
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va_end(ap);
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}
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}
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int __init setup_early_printk(char *opt)
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{
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if (early_console_initialized)
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return 1;
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base_addr = early_uartlite_console();
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if (base_addr) {
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early_console_initialized = 1;
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#ifdef CONFIG_MMU
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early_console_reg_tlb_alloc(base_addr);
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#endif
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early_printk("early_printk_console is enabled at 0x%08x\n",
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base_addr);
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/* register_console(early_console); */
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return 0;
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} else
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return 1;
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}
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void __init disable_early_printk(void)
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{
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if (!early_console_initialized || !early_console)
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return;
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printk(KERN_WARNING "disabling early console\n");
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unregister_console(early_console);
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early_console_initialized = 0;
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}
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