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linux_dsm_epyc7002/include/linux/serial_core.h
Mauro Carvalho Chehab b6adea334c 8250: fix boot hang with serial console when using with Serial Over Lan port 
Intel 8257x Ethernet boards have a feature called Serial Over Lan.

This feature works by emulating a serial port, and it is detected by
kernel as a normal 8250 port.  However, this emulation is not perfect, as
also noticed on changeset 7500b1f602.

Before this patch, the kernel were trying to check if the serial TX is
capable of work using IRQ's.

This were done with a code similar this:

        serial_outp(up, UART_IER, UART_IER_THRI);
        lsr = serial_in(up, UART_LSR);
        iir = serial_in(up, UART_IIR);
        serial_outp(up, UART_IER, 0);

        if (lsr & UART_LSR_TEMT && iir & UART_IIR_NO_INT)
		up->bugs |= UART_BUG_TXEN;

This works fine for other 8250 ports, but, on 8250-emulated SoL port, the
chip is a little lazy to down UART_IIR_NO_INT at UART_IIR register.

Due to that, UART_BUG_TXEN is sometimes enabled.  However, as TX IRQ keeps
working, and the TX polling is now enabled, the driver miss-interprets the
IRQ received later, hanging up the machine until a key is pressed at the
serial console.

This is the 6 version of this patch.  Previous versions were trying to
introduce a large enough delay between serial_outp and serial_in(up,
UART_IIR), but not taking forever.  However, the needed delay couldn't be
safely determined.

At the experimental tests, a delay of 1us solves most of the cases, but
still hangs sometimes.  Increasing the delay to 5us was better, but still
doesn't solve.  A very high delay of 50 ms seemed to work every time.

However, poking around with delays and pray for it to be enough doesn't
seem to be a good approach, even for a quirk.

So, instead of playing with random large arbitrary delays, let's just
disable UART_BUG_TXEN for all SoL ports.

[akpm@linux-foundation.org: fix warnings]
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-20 17:57:50 -08:00

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/*
* linux/drivers/char/serial_core.h
*
* Copyright (C) 2000 Deep Blue Solutions Ltd.
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef LINUX_SERIAL_CORE_H
#define LINUX_SERIAL_CORE_H
/*
* The type definitions. These are from Ted Ts'o's serial.h
*/
#define PORT_UNKNOWN 0
#define PORT_8250 1
#define PORT_16450 2
#define PORT_16550 3
#define PORT_16550A 4
#define PORT_CIRRUS 5
#define PORT_16650 6
#define PORT_16650V2 7
#define PORT_16750 8
#define PORT_STARTECH 9
#define PORT_16C950 10
#define PORT_16654 11
#define PORT_16850 12
#define PORT_RSA 13
#define PORT_NS16550A 14
#define PORT_XSCALE 15
#define PORT_RM9000 16 /* PMC-Sierra RM9xxx internal UART */
#define PORT_OCTEON 17 /* Cavium OCTEON internal UART */
#define PORT_MAX_8250 17 /* max port ID */
/*
* ARM specific type numbers. These are not currently guaranteed
* to be implemented, and will change in the future. These are
* separate so any additions to the old serial.c that occur before
* we are merged can be easily merged here.
*/
#define PORT_PXA 31
#define PORT_AMBA 32
#define PORT_CLPS711X 33
#define PORT_SA1100 34
#define PORT_UART00 35
#define PORT_21285 37
/* Sparc type numbers. */
#define PORT_SUNZILOG 38
#define PORT_SUNSAB 39
/* DEC */
#define PORT_DZ 46
#define PORT_ZS 47
/* Parisc type numbers. */
#define PORT_MUX 48
/* Atmel AT91 / AT32 SoC */
#define PORT_ATMEL 49
/* Macintosh Zilog type numbers */
#define PORT_MAC_ZILOG 50 /* m68k : not yet implemented */
#define PORT_PMAC_ZILOG 51
/* SH-SCI */
#define PORT_SCI 52
#define PORT_SCIF 53
#define PORT_IRDA 54
/* Samsung S3C2410 SoC and derivatives thereof */
#define PORT_S3C2410 55
/* SGI IP22 aka Indy / Challenge S / Indigo 2 */
#define PORT_IP22ZILOG 56
/* Sharp LH7a40x -- an ARM9 SoC series */
#define PORT_LH7A40X 57
/* PPC CPM type number */
#define PORT_CPM 58
/* MPC52xx type numbers */
#define PORT_MPC52xx 59
/* IBM icom */
#define PORT_ICOM 60
/* Samsung S3C2440 SoC */
#define PORT_S3C2440 61
/* Motorola i.MX SoC */
#define PORT_IMX 62
/* Marvell MPSC */
#define PORT_MPSC 63
/* TXX9 type number */
#define PORT_TXX9 64
/* NEC VR4100 series SIU/DSIU */
#define PORT_VR41XX_SIU 65
#define PORT_VR41XX_DSIU 66
/* Samsung S3C2400 SoC */
#define PORT_S3C2400 67
/* M32R SIO */
#define PORT_M32R_SIO 68
/*Digi jsm */
#define PORT_JSM 69
#define PORT_PNX8XXX 70
/* Hilscher netx */
#define PORT_NETX 71
/* SUN4V Hypervisor Console */
#define PORT_SUNHV 72
#define PORT_S3C2412 73
/* Xilinx uartlite */
#define PORT_UARTLITE 74
/* Blackfin bf5xx */
#define PORT_BFIN 75
/* Micrel KS8695 */
#define PORT_KS8695 76
/* Broadcom SB1250, etc. SOC */
#define PORT_SB1250_DUART 77
/* Freescale ColdFire */
#define PORT_MCF 78
/* Blackfin SPORT */
#define PORT_BFIN_SPORT 79
/* MN10300 on-chip UART numbers */
#define PORT_MN10300 80
#define PORT_MN10300_CTS 81
#define PORT_SC26XX 82
/* SH-SCI */
#define PORT_SCIFA 83
#define PORT_S3C6400 84
/* NWPSERIAL */
#define PORT_NWPSERIAL 85
#ifdef __KERNEL__
#include <linux/compiler.h>
#include <linux/interrupt.h>
#include <linux/circ_buf.h>
#include <linux/spinlock.h>
#include <linux/sched.h>
#include <linux/tty.h>
#include <linux/mutex.h>
#include <linux/sysrq.h>
struct uart_port;
struct uart_info;
struct serial_struct;
struct device;
/*
* This structure describes all the operations that can be
* done on the physical hardware.
*/
struct uart_ops {
unsigned int (*tx_empty)(struct uart_port *);
void (*set_mctrl)(struct uart_port *, unsigned int mctrl);
unsigned int (*get_mctrl)(struct uart_port *);
void (*stop_tx)(struct uart_port *);
void (*start_tx)(struct uart_port *);
void (*send_xchar)(struct uart_port *, char ch);
void (*stop_rx)(struct uart_port *);
void (*enable_ms)(struct uart_port *);
void (*break_ctl)(struct uart_port *, int ctl);
int (*startup)(struct uart_port *);
void (*shutdown)(struct uart_port *);
void (*flush_buffer)(struct uart_port *);
void (*set_termios)(struct uart_port *, struct ktermios *new,
struct ktermios *old);
void (*set_ldisc)(struct uart_port *);
void (*pm)(struct uart_port *, unsigned int state,
unsigned int oldstate);
int (*set_wake)(struct uart_port *, unsigned int state);
/*
* Return a string describing the type of the port
*/
const char *(*type)(struct uart_port *);
/*
* Release IO and memory resources used by the port.
* This includes iounmap if necessary.
*/
void (*release_port)(struct uart_port *);
/*
* Request IO and memory resources used by the port.
* This includes iomapping the port if necessary.
*/
int (*request_port)(struct uart_port *);
void (*config_port)(struct uart_port *, int);
int (*verify_port)(struct uart_port *, struct serial_struct *);
int (*ioctl)(struct uart_port *, unsigned int, unsigned long);
#ifdef CONFIG_CONSOLE_POLL
void (*poll_put_char)(struct uart_port *, unsigned char);
int (*poll_get_char)(struct uart_port *);
#endif
};
#define UART_CONFIG_TYPE (1 << 0)
#define UART_CONFIG_IRQ (1 << 1)
struct uart_icount {
__u32 cts;
__u32 dsr;
__u32 rng;
__u32 dcd;
__u32 rx;
__u32 tx;
__u32 frame;
__u32 overrun;
__u32 parity;
__u32 brk;
__u32 buf_overrun;
};
typedef unsigned int __bitwise__ upf_t;
struct uart_port {
spinlock_t lock; /* port lock */
unsigned long iobase; /* in/out[bwl] */
unsigned char __iomem *membase; /* read/write[bwl] */
unsigned int (*serial_in)(struct uart_port *, int);
void (*serial_out)(struct uart_port *, int, int);
unsigned int irq; /* irq number */
unsigned int uartclk; /* base uart clock */
unsigned int fifosize; /* tx fifo size */
unsigned char x_char; /* xon/xoff char */
unsigned char regshift; /* reg offset shift */
unsigned char iotype; /* io access style */
unsigned char unused1;
#define UPIO_PORT (0)
#define UPIO_HUB6 (1)
#define UPIO_MEM (2)
#define UPIO_MEM32 (3)
#define UPIO_AU (4) /* Au1x00 type IO */
#define UPIO_TSI (5) /* Tsi108/109 type IO */
#define UPIO_DWAPB (6) /* DesignWare APB UART */
#define UPIO_RM9000 (7) /* RM9000 type IO */
unsigned int read_status_mask; /* driver specific */
unsigned int ignore_status_mask; /* driver specific */
struct uart_info *info; /* pointer to parent info */
struct uart_icount icount; /* statistics */
struct console *cons; /* struct console, if any */
#ifdef CONFIG_SERIAL_CORE_CONSOLE
unsigned long sysrq; /* sysrq timeout */
#endif
upf_t flags;
#define UPF_FOURPORT ((__force upf_t) (1 << 1))
#define UPF_SAK ((__force upf_t) (1 << 2))
#define UPF_SPD_MASK ((__force upf_t) (0x1030))
#define UPF_SPD_HI ((__force upf_t) (0x0010))
#define UPF_SPD_VHI ((__force upf_t) (0x0020))
#define UPF_SPD_CUST ((__force upf_t) (0x0030))
#define UPF_SPD_SHI ((__force upf_t) (0x1000))
#define UPF_SPD_WARP ((__force upf_t) (0x1010))
#define UPF_SKIP_TEST ((__force upf_t) (1 << 6))
#define UPF_AUTO_IRQ ((__force upf_t) (1 << 7))
#define UPF_HARDPPS_CD ((__force upf_t) (1 << 11))
#define UPF_LOW_LATENCY ((__force upf_t) (1 << 13))
#define UPF_BUGGY_UART ((__force upf_t) (1 << 14))
#define UPF_NO_TXEN_TEST ((__force upf_t) (1 << 15))
#define UPF_MAGIC_MULTIPLIER ((__force upf_t) (1 << 16))
#define UPF_CONS_FLOW ((__force upf_t) (1 << 23))
#define UPF_SHARE_IRQ ((__force upf_t) (1 << 24))
/* The exact UART type is known and should not be probed. */
#define UPF_FIXED_TYPE ((__force upf_t) (1 << 27))
#define UPF_BOOT_AUTOCONF ((__force upf_t) (1 << 28))
#define UPF_FIXED_PORT ((__force upf_t) (1 << 29))
#define UPF_DEAD ((__force upf_t) (1 << 30))
#define UPF_IOREMAP ((__force upf_t) (1 << 31))
#define UPF_CHANGE_MASK ((__force upf_t) (0x17fff))
#define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
unsigned int mctrl; /* current modem ctrl settings */
unsigned int timeout; /* character-based timeout */
unsigned int type; /* port type */
const struct uart_ops *ops;
unsigned int custom_divisor;
unsigned int line; /* port index */
resource_size_t mapbase; /* for ioremap */
struct device *dev; /* parent device */
unsigned char hub6; /* this should be in the 8250 driver */
unsigned char suspended;
unsigned char unused[2];
void *private_data; /* generic platform data pointer */
};
/*
* This is the state information which is only valid when the port
* is open; it may be cleared the core driver once the device has
* been closed. Either the low level driver or the core can modify
* stuff here.
*/
typedef unsigned int __bitwise__ uif_t;
struct uart_info {
struct tty_port port;
struct circ_buf xmit;
uif_t flags;
/*
* Definitions for info->flags. These are _private_ to serial_core, and
* are specific to this structure. They may be queried by low level drivers.
*
* FIXME: use the ASY_ definitions
*/
#define UIF_CHECK_CD ((__force uif_t) (1 << 25))
#define UIF_CTS_FLOW ((__force uif_t) (1 << 26))
#define UIF_NORMAL_ACTIVE ((__force uif_t) (1 << 29))
#define UIF_INITIALIZED ((__force uif_t) (1 << 31))
#define UIF_SUSPENDED ((__force uif_t) (1 << 30))
struct tasklet_struct tlet;
wait_queue_head_t delta_msr_wait;
};
/*
* This is the state information which is persistent across opens.
* The low level driver must not to touch any elements contained
* within.
*/
struct uart_state {
unsigned int close_delay; /* msec */
unsigned int closing_wait; /* msec */
#define USF_CLOSING_WAIT_INF (0)
#define USF_CLOSING_WAIT_NONE (~0U)
int count;
int pm_state;
struct uart_info info;
struct uart_port *port;
struct mutex mutex;
};
#define UART_XMIT_SIZE PAGE_SIZE
/* number of characters left in xmit buffer before we ask for more */
#define WAKEUP_CHARS 256
struct module;
struct tty_driver;
struct uart_driver {
struct module *owner;
const char *driver_name;
const char *dev_name;
int major;
int minor;
int nr;
struct console *cons;
/*
* these are private; the low level driver should not
* touch these; they should be initialised to NULL
*/
struct uart_state *state;
struct tty_driver *tty_driver;
};
void uart_write_wakeup(struct uart_port *port);
/*
* Baud rate helpers.
*/
void uart_update_timeout(struct uart_port *port, unsigned int cflag,
unsigned int baud);
unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
struct ktermios *old, unsigned int min,
unsigned int max);
unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
/*
* Console helpers.
*/
struct uart_port *uart_get_console(struct uart_port *ports, int nr,
struct console *c);
void uart_parse_options(char *options, int *baud, int *parity, int *bits,
int *flow);
int uart_set_options(struct uart_port *port, struct console *co, int baud,
int parity, int bits, int flow);
struct tty_driver *uart_console_device(struct console *co, int *index);
void uart_console_write(struct uart_port *port, const char *s,
unsigned int count,
void (*putchar)(struct uart_port *, int));
/*
* Port/driver registration/removal
*/
int uart_register_driver(struct uart_driver *uart);
void uart_unregister_driver(struct uart_driver *uart);
int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
int uart_match_port(struct uart_port *port1, struct uart_port *port2);
/*
* Power Management
*/
int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
#define uart_circ_empty(circ) ((circ)->head == (circ)->tail)
#define uart_circ_clear(circ) ((circ)->head = (circ)->tail = 0)
#define uart_circ_chars_pending(circ) \
(CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
#define uart_circ_chars_free(circ) \
(CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
static inline int uart_tx_stopped(struct uart_port *port)
{
struct tty_struct *tty = port->info->port.tty;
if(tty->stopped || tty->hw_stopped)
return 1;
return 0;
}
/*
* The following are helper functions for the low level drivers.
*/
static inline int
uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
{
#ifdef SUPPORT_SYSRQ
if (port->sysrq) {
if (ch && time_before(jiffies, port->sysrq)) {
handle_sysrq(ch, port->info->port.tty);
port->sysrq = 0;
return 1;
}
port->sysrq = 0;
}
#endif
return 0;
}
#ifndef SUPPORT_SYSRQ
#define uart_handle_sysrq_char(port,ch) uart_handle_sysrq_char(port, 0)
#endif
/*
* We do the SysRQ and SAK checking like this...
*/
static inline int uart_handle_break(struct uart_port *port)
{
struct uart_info *info = port->info;
#ifdef SUPPORT_SYSRQ
if (port->cons && port->cons->index == port->line) {
if (!port->sysrq) {
port->sysrq = jiffies + HZ*5;
return 1;
}
port->sysrq = 0;
}
#endif
if (port->flags & UPF_SAK)
do_SAK(info->port.tty);
return 0;
}
/**
* uart_handle_dcd_change - handle a change of carrier detect state
* @port: uart_port structure for the open port
* @status: new carrier detect status, nonzero if active
*/
static inline void
uart_handle_dcd_change(struct uart_port *port, unsigned int status)
{
struct uart_info *info = port->info;
port->icount.dcd++;
#ifdef CONFIG_HARD_PPS
if ((port->flags & UPF_HARDPPS_CD) && status)
hardpps();
#endif
if (info->flags & UIF_CHECK_CD) {
if (status)
wake_up_interruptible(&info->port.open_wait);
else if (info->port.tty)
tty_hangup(info->port.tty);
}
}
/**
* uart_handle_cts_change - handle a change of clear-to-send state
* @port: uart_port structure for the open port
* @status: new clear to send status, nonzero if active
*/
static inline void
uart_handle_cts_change(struct uart_port *port, unsigned int status)
{
struct uart_info *info = port->info;
struct tty_struct *tty = info->port.tty;
port->icount.cts++;
if (info->flags & UIF_CTS_FLOW) {
if (tty->hw_stopped) {
if (status) {
tty->hw_stopped = 0;
port->ops->start_tx(port);
uart_write_wakeup(port);
}
} else {
if (!status) {
tty->hw_stopped = 1;
port->ops->stop_tx(port);
}
}
}
}
#include <linux/tty_flip.h>
static inline void
uart_insert_char(struct uart_port *port, unsigned int status,
unsigned int overrun, unsigned int ch, unsigned int flag)
{
struct tty_struct *tty = port->info->port.tty;
if ((status & port->ignore_status_mask & ~overrun) == 0)
tty_insert_flip_char(tty, ch, flag);
/*
* Overrun is special. Since it's reported immediately,
* it doesn't affect the current character.
*/
if (status & ~port->ignore_status_mask & overrun)
tty_insert_flip_char(tty, 0, TTY_OVERRUN);
}
/*
* UART_ENABLE_MS - determine if port should enable modem status irqs
*/
#define UART_ENABLE_MS(port,cflag) ((port)->flags & UPF_HARDPPS_CD || \
(cflag) & CRTSCTS || \
!((cflag) & CLOCAL))
#endif
#endif /* LINUX_SERIAL_CORE_H */
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