af9c724907
When the console is on a serial port to be driven by serial8250, a character can be lost from the end of the first line in the two-line sequence serial8250.0: ttyS0 at MMIO 0xe0004500 (irq = 42) is a 16550A console handover: boot [udbg0] -> real [ttyS0] This happens because udbg_puts or udbg_write stuff the last byte of the line into the Tx FIFO and return, whereupon the serial8250 initialization code immediately empties that FIFO. The fix: udbg_puts and udbg_write now wait for the Tx FIFO to clear before returning. This delays the system by one additional serial frame time for each line written by udbg, but the effect is not noticeable, a cumulative 17 milliseconds for 200 lines of early printk output at 115200 baud. Also, the routines in udbg_16550.c now emit CRLF instead of LFCR. Linux makes a point of emitting CRLF because, when serial output is captured to a file, LFCR sequences can confuse text editors. See http://lkml.org/lkml/2006/2/4/50 for some history. Signed-off-by: Andrew Klossner <andrew@cesa.opbu.xerox.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
56 lines
1.8 KiB
C
56 lines
1.8 KiB
C
/*
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* (c) 2001, 2006 IBM Corporation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef _ASM_POWERPC_UDBG_H
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#define _ASM_POWERPC_UDBG_H
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#ifdef __KERNEL__
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#include <linux/compiler.h>
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#include <linux/init.h>
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extern void (*udbg_putc)(char c);
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extern void (*udbg_flush)(void);
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extern int (*udbg_getc)(void);
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extern int (*udbg_getc_poll)(void);
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extern void udbg_puts(const char *s);
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extern int udbg_write(const char *s, int n);
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extern int udbg_read(char *buf, int buflen);
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extern void register_early_udbg_console(void);
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extern void udbg_printf(const char *fmt, ...)
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__attribute__ ((format (printf, 1, 2)));
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extern void udbg_progress(char *s, unsigned short hex);
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extern void udbg_init_uart(void __iomem *comport, unsigned int speed,
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unsigned int clock);
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extern unsigned int udbg_probe_uart_speed(void __iomem *comport,
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unsigned int clock);
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struct device_node;
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extern void udbg_scc_init(int force_scc);
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extern int udbg_adb_init(int force_btext);
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extern void udbg_adb_init_early(void);
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extern void __init udbg_early_init(void);
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extern void __init udbg_init_debug_lpar(void);
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extern void __init udbg_init_pmac_realmode(void);
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extern void __init udbg_init_maple_realmode(void);
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extern void __init udbg_init_pas_realmode(void);
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extern void __init udbg_init_iseries(void);
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extern void __init udbg_init_rtas_panel(void);
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extern void __init udbg_init_rtas_console(void);
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extern void __init udbg_init_debug_beat(void);
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extern void __init udbg_init_btext(void);
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extern void __init udbg_init_44x_as1(void);
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extern void __init udbg_init_40x_realmode(void);
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extern void __init udbg_init_cpm(void);
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_UDBG_H */
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