9deaa53ac7
Sending a break on the SOC UARTs found in some MPC83xx/85xx/86xx chips seems to cause a short lived IRQ storm (/proc/interrupts typically shows somewhere between 300 and 1500 events). Unfortunately this renders SysRQ over the serial console completely inoperable. The suggested workaround in the errata is to read the Rx register, wait one character period, and then read the Rx register again. We achieve this by tracking the old LSR value, and on the subsequent interrupt event after a break, we don't read LSR, instead we just read the RBR again and return immediately. The "fsl,ns16550" is used in the compatible field of the serial device to mark UARTs known to have this issue. Thanks to Scott Wood for providing the errata data which led to a much cleaner fix. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
96 lines
3.1 KiB
C
96 lines
3.1 KiB
C
/*
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* linux/include/linux/serial_8250.h
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*
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* Copyright (C) 2004 Russell King
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#ifndef _LINUX_SERIAL_8250_H
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#define _LINUX_SERIAL_8250_H
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#include <linux/serial_core.h>
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#include <linux/platform_device.h>
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/*
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* This is the platform device platform_data structure
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*/
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struct plat_serial8250_port {
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unsigned long iobase; /* io base address */
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void __iomem *membase; /* ioremap cookie or NULL */
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resource_size_t mapbase; /* resource base */
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unsigned int irq; /* interrupt number */
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unsigned long irqflags; /* request_irq flags */
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unsigned int uartclk; /* UART clock rate */
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void *private_data;
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unsigned char regshift; /* register shift */
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unsigned char iotype; /* UPIO_* */
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unsigned char hub6;
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upf_t flags; /* UPF_* flags */
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unsigned int type; /* If UPF_FIXED_TYPE */
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unsigned int (*serial_in)(struct uart_port *, int);
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void (*serial_out)(struct uart_port *, int, int);
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void (*set_termios)(struct uart_port *,
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struct ktermios *new,
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struct ktermios *old);
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int (*handle_irq)(struct uart_port *);
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void (*pm)(struct uart_port *, unsigned int state,
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unsigned old);
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};
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/*
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* Allocate 8250 platform device IDs. Nothing is implied by
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* the numbering here, except for the legacy entry being -1.
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*/
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enum {
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PLAT8250_DEV_LEGACY = -1,
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PLAT8250_DEV_PLATFORM,
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PLAT8250_DEV_PLATFORM1,
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PLAT8250_DEV_PLATFORM2,
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PLAT8250_DEV_FOURPORT,
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PLAT8250_DEV_ACCENT,
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PLAT8250_DEV_BOCA,
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PLAT8250_DEV_EXAR_ST16C554,
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PLAT8250_DEV_HUB6,
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PLAT8250_DEV_MCA,
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PLAT8250_DEV_AU1X00,
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PLAT8250_DEV_SM501,
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};
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/*
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* This should be used by drivers which want to register
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* their own 8250 ports without registering their own
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* platform device. Using these will make your driver
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* dependent on the 8250 driver.
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*/
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struct uart_port;
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struct uart_8250_port;
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int serial8250_register_port(struct uart_port *);
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void serial8250_unregister_port(int line);
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void serial8250_suspend_port(int line);
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void serial8250_resume_port(int line);
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extern int early_serial_setup(struct uart_port *port);
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extern int serial8250_find_port(struct uart_port *p);
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extern int serial8250_find_port_for_earlycon(void);
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extern int setup_early_serial8250_console(char *cmdline);
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extern void serial8250_do_set_termios(struct uart_port *port,
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struct ktermios *termios, struct ktermios *old);
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extern void serial8250_do_pm(struct uart_port *port, unsigned int state,
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unsigned int oldstate);
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extern int fsl8250_handle_irq(struct uart_port *port);
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int serial8250_handle_irq(struct uart_port *port, unsigned int iir);
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unsigned char serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr);
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void serial8250_tx_chars(struct uart_8250_port *up);
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unsigned int serial8250_modem_status(struct uart_8250_port *up);
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extern void serial8250_set_isa_configurator(void (*v)
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(int port, struct uart_port *up,
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unsigned short *capabilities));
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#endif
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