kernel-ark/drivers/serial/sn_console.c
Russell King b129a8ccd5 [SERIAL] Clean up and fix tty transmission start/stoping
The start_tx and stop_tx methods were passed a flag to indicate
whether the start/stop was from the tty start/stop callbacks, and
some drivers used this flag to decide whether to ask the UART to
immediately stop transmission (where the UART supports such a
feature.)

There are other cases when we wish this to occur - when CTS is
lowered, or if we change from soft to hard flow control and CTS
is inactive.  In these cases, this flag was false, and we would
allow the transmitter to drain before stopping.

There is really only one case where we want to let the transmitter
drain before disabling, and that's when we run out of characters
to send.

Hence, re-jig the start_tx and stop_tx methods to eliminate this
flag, and introduce new functions for the special "disable and
allow transmitter to drain" case.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-08-31 10:12:14 +01:00

1125 lines
30 KiB
C

/*
* C-Brick Serial Port (and console) driver for SGI Altix machines.
*
* This driver is NOT suitable for talking to the l1-controller for
* anything other than 'console activities' --- please use the l1
* driver for that.
*
*
* Copyright (c) 2004-2005 Silicon Graphics, Inc. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of version 2 of the GNU General Public License
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*
* Further, this software is distributed without any warranty that it is
* free of the rightful claim of any third person regarding infringement
* or the like. Any license provided herein, whether implied or
* otherwise, applies only to this software file. Patent licenses, if
* any, provided herein do not apply to combinations of this program with
* other software, or any other product whatsoever.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
*
* Contact information: Silicon Graphics, Inc., 1500 Crittenden Lane,
* Mountain View, CA 94043, or:
*
* http://www.sgi.com
*
* For further information regarding this notice, see:
*
* http://oss.sgi.com/projects/GenInfo/NoticeExplan
*/
#include <linux/config.h>
#include <linux/interrupt.h>
#include <linux/tty.h>
#include <linux/serial.h>
#include <linux/console.h>
#include <linux/module.h>
#include <linux/sysrq.h>
#include <linux/circ_buf.h>
#include <linux/serial_reg.h>
#include <linux/delay.h> /* for mdelay */
#include <linux/miscdevice.h>
#include <linux/serial_core.h>
#include <asm/io.h>
#include <asm/sn/simulator.h>
#include <asm/sn/sn_sal.h>
/* number of characters we can transmit to the SAL console at a time */
#define SN_SAL_MAX_CHARS 120
/* 64K, when we're asynch, it must be at least printk's LOG_BUF_LEN to
* avoid losing chars, (always has to be a power of 2) */
#define SN_SAL_BUFFER_SIZE (64 * (1 << 10))
#define SN_SAL_UART_FIFO_DEPTH 16
#define SN_SAL_UART_FIFO_SPEED_CPS 9600/10
/* sn_transmit_chars() calling args */
#define TRANSMIT_BUFFERED 0
#define TRANSMIT_RAW 1
/* To use dynamic numbers only and not use the assigned major and minor,
* define the following.. */
/* #define USE_DYNAMIC_MINOR 1 *//* use dynamic minor number */
#define USE_DYNAMIC_MINOR 0 /* Don't rely on misc_register dynamic minor */
/* Device name we're using */
#define DEVICE_NAME "ttySG"
#define DEVICE_NAME_DYNAMIC "ttySG0" /* need full name for misc_register */
/* The major/minor we are using, ignored for USE_DYNAMIC_MINOR */
#define DEVICE_MAJOR 204
#define DEVICE_MINOR 40
#ifdef CONFIG_MAGIC_SYSRQ
static char sysrq_serial_str[] = "\eSYS";
static char *sysrq_serial_ptr = sysrq_serial_str;
static unsigned long sysrq_requested;
#endif /* CONFIG_MAGIC_SYSRQ */
/*
* Port definition - this kinda drives it all
*/
struct sn_cons_port {
struct timer_list sc_timer;
struct uart_port sc_port;
struct sn_sal_ops {
int (*sal_puts_raw) (const char *s, int len);
int (*sal_puts) (const char *s, int len);
int (*sal_getc) (void);
int (*sal_input_pending) (void);
void (*sal_wakeup_transmit) (struct sn_cons_port *, int);
} *sc_ops;
unsigned long sc_interrupt_timeout;
int sc_is_asynch;
};
static struct sn_cons_port sal_console_port;
static int sn_process_input;
/* Only used if USE_DYNAMIC_MINOR is set to 1 */
static struct miscdevice misc; /* used with misc_register for dynamic */
extern void early_sn_setup(void);
#undef DEBUG
#ifdef DEBUG
static int sn_debug_printf(const char *fmt, ...);
#define DPRINTF(x...) sn_debug_printf(x)
#else
#define DPRINTF(x...) do { } while (0)
#endif
/* Prototypes */
static int snt_hw_puts_raw(const char *, int);
static int snt_hw_puts_buffered(const char *, int);
static int snt_poll_getc(void);
static int snt_poll_input_pending(void);
static int snt_intr_getc(void);
static int snt_intr_input_pending(void);
static void sn_transmit_chars(struct sn_cons_port *, int);
/* A table for polling:
*/
static struct sn_sal_ops poll_ops = {
.sal_puts_raw = snt_hw_puts_raw,
.sal_puts = snt_hw_puts_raw,
.sal_getc = snt_poll_getc,
.sal_input_pending = snt_poll_input_pending
};
/* A table for interrupts enabled */
static struct sn_sal_ops intr_ops = {
.sal_puts_raw = snt_hw_puts_raw,
.sal_puts = snt_hw_puts_buffered,
.sal_getc = snt_intr_getc,
.sal_input_pending = snt_intr_input_pending,
.sal_wakeup_transmit = sn_transmit_chars
};
/* the console does output in two distinctly different ways:
* synchronous (raw) and asynchronous (buffered). initally, early_printk
* does synchronous output. any data written goes directly to the SAL
* to be output (incidentally, it is internally buffered by the SAL)
* after interrupts and timers are initialized and available for use,
* the console init code switches to asynchronous output. this is
* also the earliest opportunity to begin polling for console input.
* after console initialization, console output and tty (serial port)
* output is buffered and sent to the SAL asynchronously (either by
* timer callback or by UART interrupt) */
/* routines for running the console in polling mode */
/**
* snt_poll_getc - Get a character from the console in polling mode
*
*/
static int snt_poll_getc(void)
{
int ch;
ia64_sn_console_getc(&ch);
return ch;
}
/**
* snt_poll_input_pending - Check if any input is waiting - polling mode.
*
*/
static int snt_poll_input_pending(void)
{
int status, input;
status = ia64_sn_console_check(&input);
return !status && input;
}
/* routines for an interrupt driven console (normal) */
/**
* snt_intr_getc - Get a character from the console, interrupt mode
*
*/
static int snt_intr_getc(void)
{
return ia64_sn_console_readc();
}
/**
* snt_intr_input_pending - Check if input is pending, interrupt mode
*
*/
static int snt_intr_input_pending(void)
{
return ia64_sn_console_intr_status() & SAL_CONSOLE_INTR_RECV;
}
/* these functions are polled and interrupt */
/**
* snt_hw_puts_raw - Send raw string to the console, polled or interrupt mode
* @s: String
* @len: Length
*
*/
static int snt_hw_puts_raw(const char *s, int len)
{
/* this will call the PROM and not return until this is done */
return ia64_sn_console_putb(s, len);
}
/**
* snt_hw_puts_buffered - Send string to console, polled or interrupt mode
* @s: String
* @len: Length
*
*/
static int snt_hw_puts_buffered(const char *s, int len)
{
/* queue data to the PROM */
return ia64_sn_console_xmit_chars((char *)s, len);
}
/* uart interface structs
* These functions are associated with the uart_port that the serial core
* infrastructure calls.
*
* Note: Due to how the console works, many routines are no-ops.
*/
/**
* snp_type - What type of console are we?
* @port: Port to operate with (we ignore since we only have one port)
*
*/
static const char *snp_type(struct uart_port *port)
{
return ("SGI SN L1");
}
/**
* snp_tx_empty - Is the transmitter empty? We pretend we're always empty
* @port: Port to operate on (we ignore since we only have one port)
*
*/
static unsigned int snp_tx_empty(struct uart_port *port)
{
return 1;
}
/**
* snp_stop_tx - stop the transmitter - no-op for us
* @port: Port to operat eon - we ignore - no-op function
*
*/
static void snp_stop_tx(struct uart_port *port)
{
}
/**
* snp_release_port - Free i/o and resources for port - no-op for us
* @port: Port to operate on - we ignore - no-op function
*
*/
static void snp_release_port(struct uart_port *port)
{
}
/**
* snp_enable_ms - Force modem status interrupts on - no-op for us
* @port: Port to operate on - we ignore - no-op function
*
*/
static void snp_enable_ms(struct uart_port *port)
{
}
/**
* snp_shutdown - shut down the port - free irq and disable - no-op for us
* @port: Port to shut down - we ignore
*
*/
static void snp_shutdown(struct uart_port *port)
{
}
/**
* snp_set_mctrl - set control lines (dtr, rts, etc) - no-op for our console
* @port: Port to operate on - we ignore
* @mctrl: Lines to set/unset - we ignore
*
*/
static void snp_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
}
/**
* snp_get_mctrl - get contorl line info, we just return a static value
* @port: port to operate on - we only have one port so we ignore this
*
*/
static unsigned int snp_get_mctrl(struct uart_port *port)
{
return TIOCM_CAR | TIOCM_RNG | TIOCM_DSR | TIOCM_CTS;
}
/**
* snp_stop_rx - Stop the receiver - we ignor ethis
* @port: Port to operate on - we ignore
*
*/
static void snp_stop_rx(struct uart_port *port)
{
}
/**
* snp_start_tx - Start transmitter
* @port: Port to operate on
*
*/
static void snp_start_tx(struct uart_port *port)
{
if (sal_console_port.sc_ops->sal_wakeup_transmit)
sal_console_port.sc_ops->sal_wakeup_transmit(&sal_console_port,
TRANSMIT_BUFFERED);
}
/**
* snp_break_ctl - handle breaks - ignored by us
* @port: Port to operate on
* @break_state: Break state
*
*/
static void snp_break_ctl(struct uart_port *port, int break_state)
{
}
/**
* snp_startup - Start up the serial port - always return 0 (We're always on)
* @port: Port to operate on
*
*/
static int snp_startup(struct uart_port *port)
{
return 0;
}
/**
* snp_set_termios - set termios stuff - we ignore these
* @port: port to operate on
* @termios: New settings
* @termios: Old
*
*/
static void
snp_set_termios(struct uart_port *port, struct termios *termios,
struct termios *old)
{
}
/**
* snp_request_port - allocate resources for port - ignored by us
* @port: port to operate on
*
*/
static int snp_request_port(struct uart_port *port)
{
return 0;
}
/**
* snp_config_port - allocate resources, set up - we ignore, we're always on
* @port: Port to operate on
* @flags: flags used for port setup
*
*/
static void snp_config_port(struct uart_port *port, int flags)
{
}
/* Associate the uart functions above - given to serial core */
static struct uart_ops sn_console_ops = {
.tx_empty = snp_tx_empty,
.set_mctrl = snp_set_mctrl,
.get_mctrl = snp_get_mctrl,
.stop_tx = snp_stop_tx,
.start_tx = snp_start_tx,
.stop_rx = snp_stop_rx,
.enable_ms = snp_enable_ms,
.break_ctl = snp_break_ctl,
.startup = snp_startup,
.shutdown = snp_shutdown,
.set_termios = snp_set_termios,
.pm = NULL,
.type = snp_type,
.release_port = snp_release_port,
.request_port = snp_request_port,
.config_port = snp_config_port,
.verify_port = NULL,
};
/* End of uart struct functions and defines */
#ifdef DEBUG
/**
* sn_debug_printf - close to hardware debugging printf
* @fmt: printf format
*
* This is as "close to the metal" as we can get, used when the driver
* itself may be broken.
*
*/
static int sn_debug_printf(const char *fmt, ...)
{
static char printk_buf[1024];
int printed_len;
va_list args;
va_start(args, fmt);
printed_len = vsnprintf(printk_buf, sizeof(printk_buf), fmt, args);
if (!sal_console_port.sc_ops) {
sal_console_port.sc_ops = &poll_ops;
early_sn_setup();
}
sal_console_port.sc_ops->sal_puts_raw(printk_buf, printed_len);
va_end(args);
return printed_len;
}
#endif /* DEBUG */
/*
* Interrupt handling routines.
*/
/**
* sn_receive_chars - Grab characters, pass them to tty layer
* @port: Port to operate on
* @regs: Saved registers (needed by uart_handle_sysrq_char)
* @flags: irq flags
*
* Note: If we're not registered with the serial core infrastructure yet,
* we don't try to send characters to it...
*
*/
static void
sn_receive_chars(struct sn_cons_port *port, struct pt_regs *regs,
unsigned long flags)
{
int ch;
struct tty_struct *tty;
if (!port) {
printk(KERN_ERR "sn_receive_chars - port NULL so can't receieve\n");
return;
}
if (!port->sc_ops) {
printk(KERN_ERR "sn_receive_chars - port->sc_ops NULL so can't receieve\n");
return;
}
if (port->sc_port.info) {
/* The serial_core stuffs are initilized, use them */
tty = port->sc_port.info->tty;
}
else {
/* Not registered yet - can't pass to tty layer. */
tty = NULL;
}
while (port->sc_ops->sal_input_pending()) {
ch = port->sc_ops->sal_getc();
if (ch < 0) {
printk(KERN_ERR "sn_console: An error occured while "
"obtaining data from the console (0x%0x)\n", ch);
break;
}
#ifdef CONFIG_MAGIC_SYSRQ
if (sysrq_requested) {
unsigned long sysrq_timeout = sysrq_requested + HZ*5;
sysrq_requested = 0;
if (ch && time_before(jiffies, sysrq_timeout)) {
spin_unlock_irqrestore(&port->sc_port.lock, flags);
handle_sysrq(ch, regs, NULL);
spin_lock_irqsave(&port->sc_port.lock, flags);
/* ignore actual sysrq command char */
continue;
}
}
if (ch == *sysrq_serial_ptr) {
if (!(*++sysrq_serial_ptr)) {
sysrq_requested = jiffies;
sysrq_serial_ptr = sysrq_serial_str;
}
/*
* ignore the whole sysrq string except for the
* leading escape
*/
if (ch != '\e')
continue;
}
else
sysrq_serial_ptr = sysrq_serial_str;
#endif /* CONFIG_MAGIC_SYSRQ */
/* record the character to pass up to the tty layer */
if (tty) {
*tty->flip.char_buf_ptr = ch;
*tty->flip.flag_buf_ptr = TTY_NORMAL;
tty->flip.char_buf_ptr++;
tty->flip.count++;
if (tty->flip.count == TTY_FLIPBUF_SIZE)
break;
}
port->sc_port.icount.rx++;
}
if (tty)
tty_flip_buffer_push(tty);
}
/**
* sn_transmit_chars - grab characters from serial core, send off
* @port: Port to operate on
* @raw: Transmit raw or buffered
*
* Note: If we're early, before we're registered with serial core, the
* writes are going through sn_sal_console_write because that's how
* register_console has been set up. We currently could have asynch
* polls calling this function due to sn_sal_switch_to_asynch but we can
* ignore them until we register with the serial core stuffs.
*
*/
static void sn_transmit_chars(struct sn_cons_port *port, int raw)
{
int xmit_count, tail, head, loops, ii;
int result;
char *start;
struct circ_buf *xmit;
if (!port)
return;
BUG_ON(!port->sc_is_asynch);
if (port->sc_port.info) {
/* We're initilized, using serial core infrastructure */
xmit = &port->sc_port.info->xmit;
} else {
/* Probably sn_sal_switch_to_asynch has been run but serial core isn't
* initilized yet. Just return. Writes are going through
* sn_sal_console_write (due to register_console) at this time.
*/
return;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(&port->sc_port)) {
/* Nothing to do. */
ia64_sn_console_intr_disable(SAL_CONSOLE_INTR_XMIT);
return;
}
head = xmit->head;
tail = xmit->tail;
start = &xmit->buf[tail];
/* twice around gets the tail to the end of the buffer and
* then to the head, if needed */
loops = (head < tail) ? 2 : 1;
for (ii = 0; ii < loops; ii++) {
xmit_count = (head < tail) ?
(UART_XMIT_SIZE - tail) : (head - tail);
if (xmit_count > 0) {
if (raw == TRANSMIT_RAW)
result =
port->sc_ops->sal_puts_raw(start,
xmit_count);
else
result =
port->sc_ops->sal_puts(start, xmit_count);
#ifdef DEBUG
if (!result)
DPRINTF("`");
#endif
if (result > 0) {
xmit_count -= result;
port->sc_port.icount.tx += result;
tail += result;
tail &= UART_XMIT_SIZE - 1;
xmit->tail = tail;
start = &xmit->buf[tail];
}
}
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&port->sc_port);
if (uart_circ_empty(xmit))
snp_stop_tx(&port->sc_port); /* no-op for us */
}
/**
* sn_sal_interrupt - Handle console interrupts
* @irq: irq #, useful for debug statements
* @dev_id: our pointer to our port (sn_cons_port which contains the uart port)
* @regs: Saved registers, used by sn_receive_chars for uart_handle_sysrq_char
*
*/
static irqreturn_t sn_sal_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
struct sn_cons_port *port = (struct sn_cons_port *)dev_id;
unsigned long flags;
int status = ia64_sn_console_intr_status();
if (!port)
return IRQ_NONE;
spin_lock_irqsave(&port->sc_port.lock, flags);
if (status & SAL_CONSOLE_INTR_RECV) {
sn_receive_chars(port, regs, flags);
}
if (status & SAL_CONSOLE_INTR_XMIT) {
sn_transmit_chars(port, TRANSMIT_BUFFERED);
}
spin_unlock_irqrestore(&port->sc_port.lock, flags);
return IRQ_HANDLED;
}
/**
* sn_sal_connect_interrupt - Request interrupt, handled by sn_sal_interrupt
* @port: Our sn_cons_port (which contains the uart port)
*
* returns the console irq if interrupt is successfully registered, else 0
*
*/
static int sn_sal_connect_interrupt(struct sn_cons_port *port)
{
if (request_irq(SGI_UART_VECTOR, sn_sal_interrupt,
SA_INTERRUPT | SA_SHIRQ,
"SAL console driver", port) >= 0) {
return SGI_UART_VECTOR;
}
printk(KERN_INFO "sn_console: console proceeding in polled mode\n");
return 0;
}
/**
* sn_sal_timer_poll - this function handles polled console mode
* @data: A pointer to our sn_cons_port (which contains the uart port)
*
* data is the pointer that init_timer will store for us. This function is
* associated with init_timer to see if there is any console traffic.
* Obviously not used in interrupt mode
*
*/
static void sn_sal_timer_poll(unsigned long data)
{
struct sn_cons_port *port = (struct sn_cons_port *)data;
unsigned long flags;
if (!port)
return;
if (!port->sc_port.irq) {
spin_lock_irqsave(&port->sc_port.lock, flags);
if (sn_process_input)
sn_receive_chars(port, NULL, flags);
sn_transmit_chars(port, TRANSMIT_RAW);
spin_unlock_irqrestore(&port->sc_port.lock, flags);
mod_timer(&port->sc_timer,
jiffies + port->sc_interrupt_timeout);
}
}
/*
* Boot-time initialization code
*/
/**
* sn_sal_switch_to_asynch - Switch to async mode (as opposed to synch)
* @port: Our sn_cons_port (which contains the uart port)
*
* So this is used by sn_sal_serial_console_init (early on, before we're
* registered with serial core). It's also used by sn_sal_module_init
* right after we've registered with serial core. The later only happens
* if we didn't already come through here via sn_sal_serial_console_init.
*
*/
static void __init sn_sal_switch_to_asynch(struct sn_cons_port *port)
{
unsigned long flags;
if (!port)
return;
DPRINTF("sn_console: about to switch to asynchronous console\n");
/* without early_printk, we may be invoked late enough to race
* with other cpus doing console IO at this point, however
* console interrupts will never be enabled */
spin_lock_irqsave(&port->sc_port.lock, flags);
/* early_printk invocation may have done this for us */
if (!port->sc_ops)
port->sc_ops = &poll_ops;
/* we can't turn on the console interrupt (as request_irq
* calls kmalloc, which isn't set up yet), so we rely on a
* timer to poll for input and push data from the console
* buffer.
*/
init_timer(&port->sc_timer);
port->sc_timer.function = sn_sal_timer_poll;
port->sc_timer.data = (unsigned long)port;
if (IS_RUNNING_ON_SIMULATOR())
port->sc_interrupt_timeout = 6;
else {
/* 960cps / 16 char FIFO = 60HZ
* HZ / (SN_SAL_FIFO_SPEED_CPS / SN_SAL_FIFO_DEPTH) */
port->sc_interrupt_timeout =
HZ * SN_SAL_UART_FIFO_DEPTH / SN_SAL_UART_FIFO_SPEED_CPS;
}
mod_timer(&port->sc_timer, jiffies + port->sc_interrupt_timeout);
port->sc_is_asynch = 1;
spin_unlock_irqrestore(&port->sc_port.lock, flags);
}
/**
* sn_sal_switch_to_interrupts - Switch to interrupt driven mode
* @port: Our sn_cons_port (which contains the uart port)
*
* In sn_sal_module_init, after we're registered with serial core and
* the port is added, this function is called to switch us to interrupt
* mode. We were previously in asynch/polling mode (using init_timer).
*
* We attempt to switch to interrupt mode here by calling
* sn_sal_connect_interrupt. If that works out, we enable receive interrupts.
*/
static void __init sn_sal_switch_to_interrupts(struct sn_cons_port *port)
{
int irq;
unsigned long flags;
if (!port)
return;
DPRINTF("sn_console: switching to interrupt driven console\n");
spin_lock_irqsave(&port->sc_port.lock, flags);
irq = sn_sal_connect_interrupt(port);
if (irq) {
port->sc_port.irq = irq;
port->sc_ops = &intr_ops;
/* turn on receive interrupts */
ia64_sn_console_intr_enable(SAL_CONSOLE_INTR_RECV);
}
spin_unlock_irqrestore(&port->sc_port.lock, flags);
}
/*
* Kernel console definitions
*/
static void sn_sal_console_write(struct console *, const char *, unsigned);
static int __init sn_sal_console_setup(struct console *, char *);
static struct uart_driver sal_console_uart;
extern struct tty_driver *uart_console_device(struct console *, int *);
static struct console sal_console = {
.name = DEVICE_NAME,
.write = sn_sal_console_write,
.device = uart_console_device,
.setup = sn_sal_console_setup,
.index = -1, /* unspecified */
.data = &sal_console_uart,
};
#define SAL_CONSOLE &sal_console
static struct uart_driver sal_console_uart = {
.owner = THIS_MODULE,
.driver_name = "sn_console",
.dev_name = DEVICE_NAME,
.major = 0, /* major/minor set at registration time per USE_DYNAMIC_MINOR */
.minor = 0,
.nr = 1, /* one port */
.cons = SAL_CONSOLE,
};
/**
* sn_sal_module_init - When the kernel loads us, get us rolling w/ serial core
*
* Before this is called, we've been printing kernel messages in a special
* early mode not making use of the serial core infrastructure. When our
* driver is loaded for real, we register the driver and port with serial
* core and try to enable interrupt driven mode.
*
*/
static int __init sn_sal_module_init(void)
{
int retval;
if (!ia64_platform_is("sn2"))
return -ENODEV;
printk(KERN_INFO "sn_console: Console driver init\n");
if (USE_DYNAMIC_MINOR == 1) {
misc.minor = MISC_DYNAMIC_MINOR;
misc.name = DEVICE_NAME_DYNAMIC;
retval = misc_register(&misc);
if (retval != 0) {
printk
("Failed to register console device using misc_register.\n");
return -ENODEV;
}
sal_console_uart.major = MISC_MAJOR;
sal_console_uart.minor = misc.minor;
} else {
sal_console_uart.major = DEVICE_MAJOR;
sal_console_uart.minor = DEVICE_MINOR;
}
/* We register the driver and the port before switching to interrupts
* or async above so the proper uart structures are populated */
if (uart_register_driver(&sal_console_uart) < 0) {
printk
("ERROR sn_sal_module_init failed uart_register_driver, line %d\n",
__LINE__);
return -ENODEV;
}
spin_lock_init(&sal_console_port.sc_port.lock);
/* Setup the port struct with the minimum needed */
sal_console_port.sc_port.membase = (char *)1; /* just needs to be non-zero */
sal_console_port.sc_port.type = PORT_16550A;
sal_console_port.sc_port.fifosize = SN_SAL_MAX_CHARS;
sal_console_port.sc_port.ops = &sn_console_ops;
sal_console_port.sc_port.line = 0;
if (uart_add_one_port(&sal_console_uart, &sal_console_port.sc_port) < 0) {
/* error - not sure what I'd do - so I'll do nothing */
printk(KERN_ERR "%s: unable to add port\n", __FUNCTION__);
}
/* when this driver is compiled in, the console initialization
* will have already switched us into asynchronous operation
* before we get here through the module initcalls */
if (!sal_console_port.sc_is_asynch) {
sn_sal_switch_to_asynch(&sal_console_port);
}
/* at this point (module_init) we can try to turn on interrupts */
if (!IS_RUNNING_ON_SIMULATOR()) {
sn_sal_switch_to_interrupts(&sal_console_port);
}
sn_process_input = 1;
return 0;
}
/**
* sn_sal_module_exit - When we're unloaded, remove the driver/port
*
*/
static void __exit sn_sal_module_exit(void)
{
del_timer_sync(&sal_console_port.sc_timer);
uart_remove_one_port(&sal_console_uart, &sal_console_port.sc_port);
uart_unregister_driver(&sal_console_uart);
misc_deregister(&misc);
}
module_init(sn_sal_module_init);
module_exit(sn_sal_module_exit);
/**
* puts_raw_fixed - sn_sal_console_write helper for adding \r's as required
* @puts_raw : puts function to do the writing
* @s: input string
* @count: length
*
* We need a \r ahead of every \n for direct writes through
* ia64_sn_console_putb (what sal_puts_raw below actually does).
*
*/
static void puts_raw_fixed(int (*puts_raw) (const char *s, int len),
const char *s, int count)
{
const char *s1;
/* Output '\r' before each '\n' */
while ((s1 = memchr(s, '\n', count)) != NULL) {
puts_raw(s, s1 - s);
puts_raw("\r\n", 2);
count -= s1 + 1 - s;
s = s1 + 1;
}
puts_raw(s, count);
}
/**
* sn_sal_console_write - Print statements before serial core available
* @console: Console to operate on - we ignore since we have just one
* @s: String to send
* @count: length
*
* This is referenced in the console struct. It is used for early
* console printing before we register with serial core and for things
* such as kdb. The console_lock must be held when we get here.
*
* This function has some code for trying to print output even if the lock
* is held. We try to cover the case where a lock holder could have died.
* We don't use this special case code if we're not registered with serial
* core yet. After we're registered with serial core, the only time this
* function would be used is for high level kernel output like magic sys req,
* kdb, and printk's.
*/
static void
sn_sal_console_write(struct console *co, const char *s, unsigned count)
{
unsigned long flags = 0;
struct sn_cons_port *port = &sal_console_port;
#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
static int stole_lock = 0;
#endif
BUG_ON(!port->sc_is_asynch);
/* We can't look at the xmit buffer if we're not registered with serial core
* yet. So only do the fancy recovery after registering
*/
if (port->sc_port.info) {
/* somebody really wants this output, might be an
* oops, kdb, panic, etc. make sure they get it. */
#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
if (spin_is_locked(&port->sc_port.lock)) {
int lhead = port->sc_port.info->xmit.head;
int ltail = port->sc_port.info->xmit.tail;
int counter, got_lock = 0;
/*
* We attempt to determine if someone has died with the
* lock. We wait ~20 secs after the head and tail ptrs
* stop moving and assume the lock holder is not functional
* and plow ahead. If the lock is freed within the time out
* period we re-get the lock and go ahead normally. We also
* remember if we have plowed ahead so that we don't have
* to wait out the time out period again - the asumption
* is that we will time out again.
*/
for (counter = 0; counter < 150; mdelay(125), counter++) {
if (!spin_is_locked(&port->sc_port.lock)
|| stole_lock) {
if (!stole_lock) {
spin_lock_irqsave(&port->
sc_port.lock,
flags);
got_lock = 1;
}
break;
} else {
/* still locked */
if ((lhead !=
port->sc_port.info->xmit.head)
|| (ltail !=
port->sc_port.info->xmit.
tail)) {
lhead =
port->sc_port.info->xmit.
head;
ltail =
port->sc_port.info->xmit.
tail;
counter = 0;
}
}
}
/* flush anything in the serial core xmit buffer, raw */
sn_transmit_chars(port, 1);
if (got_lock) {
spin_unlock_irqrestore(&port->sc_port.lock,
flags);
stole_lock = 0;
} else {
/* fell thru */
stole_lock = 1;
}
puts_raw_fixed(port->sc_ops->sal_puts_raw, s, count);
} else {
stole_lock = 0;
#endif
spin_lock_irqsave(&port->sc_port.lock, flags);
sn_transmit_chars(port, 1);
spin_unlock_irqrestore(&port->sc_port.lock, flags);
puts_raw_fixed(port->sc_ops->sal_puts_raw, s, count);
#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
}
#endif
}
else {
/* Not yet registered with serial core - simple case */
puts_raw_fixed(port->sc_ops->sal_puts_raw, s, count);
}
}
/**
* sn_sal_console_setup - Set up console for early printing
* @co: Console to work with
* @options: Options to set
*
* Altix console doesn't do anything with baud rates, etc, anyway.
*
* This isn't required since not providing the setup function in the
* console struct is ok. However, other patches like KDB plop something
* here so providing it is easier.
*
*/
static int __init sn_sal_console_setup(struct console *co, char *options)
{
return 0;
}
/**
* sn_sal_console_write_early - simple early output routine
* @co - console struct
* @s - string to print
* @count - count
*
* Simple function to provide early output, before even
* sn_sal_serial_console_init is called. Referenced in the
* console struct registerd in sn_serial_console_early_setup.
*
*/
static void __init
sn_sal_console_write_early(struct console *co, const char *s, unsigned count)
{
puts_raw_fixed(sal_console_port.sc_ops->sal_puts_raw, s, count);
}
/* Used for very early console printing - again, before
* sn_sal_serial_console_init is run */
static struct console sal_console_early __initdata = {
.name = "sn_sal",
.write = sn_sal_console_write_early,
.flags = CON_PRINTBUFFER,
.index = -1,
};
/**
* sn_serial_console_early_setup - Sets up early console output support
*
* Register a console early on... This is for output before even
* sn_sal_serial_cosnole_init is called. This function is called from
* setup.c. This allows us to do really early polled writes. When
* sn_sal_serial_console_init is called, this console is unregistered
* and a new one registered.
*/
int __init sn_serial_console_early_setup(void)
{
if (!ia64_platform_is("sn2"))
return -1;
sal_console_port.sc_ops = &poll_ops;
spin_lock_init(&sal_console_port.sc_port.lock);
early_sn_setup(); /* Find SAL entry points */
register_console(&sal_console_early);
return 0;
}
/**
* sn_sal_serial_console_init - Early console output - set up for register
*
* This function is called when regular console init happens. Because we
* support even earlier console output with sn_serial_console_early_setup
* (called from setup.c directly), this function unregisters the really
* early console.
*
* Note: Even if setup.c doesn't register sal_console_early, unregistering
* it here doesn't hurt anything.
*
*/
static int __init sn_sal_serial_console_init(void)
{
if (ia64_platform_is("sn2")) {
sn_sal_switch_to_asynch(&sal_console_port);
DPRINTF("sn_sal_serial_console_init : register console\n");
register_console(&sal_console);
unregister_console(&sal_console_early);
}
return 0;
}
console_initcall(sn_sal_serial_console_init);