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linux/drivers/serial/dz.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

823 lines
19 KiB
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/*
* dz.c: Serial port driver for DECStations equiped
* with the DZ chipset.
*
* Copyright (C) 1998 Olivier A. D. Lebaillif
*
* Email: olivier.lebaillif@ifrsys.com
*
* [31-AUG-98] triemer
* Changed IRQ to use Harald's dec internals interrupts.h
* removed base_addr code - moving address assignment to setup.c
* Changed name of dz_init to rs_init to be consistent with tc code
* [13-NOV-98] triemer fixed code to receive characters
* after patches by harald to irq code.
* [09-JAN-99] triemer minor fix for schedule - due to removal of timeout
* field from "current" - somewhere between 2.1.121 and 2.1.131
Qua Jun 27 15:02:26 BRT 2001
* [27-JUN-2001] Arnaldo Carvalho de Melo <acme@conectiva.com.br> - cleanups
*
* Parts (C) 1999 David Airlie, airlied@linux.ie
* [07-SEP-99] Bugfixes
*
* [06-Jan-2002] Russell King <rmk@arm.linux.org.uk>
* Converted to new serial core
*/
#undef DEBUG_DZ
#include <linux/config.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <asm/bootinfo.h>
#include <asm/dec/interrupts.h>
#include <asm/dec/kn01.h>
#include <asm/dec/kn02.h>
#include <asm/dec/machtype.h>
#include <asm/dec/prom.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#define CONSOLE_LINE (3) /* for definition of struct console */
#include "dz.h"
#define DZ_INTR_DEBUG 1
static char *dz_name = "DECstation DZ serial driver version ";
static char *dz_version = "1.02";
struct dz_port {
struct uart_port port;
unsigned int cflag;
};
static struct dz_port dz_ports[DZ_NB_PORT];
#ifdef DEBUG_DZ
/*
* debugging code to send out chars via prom
*/
static void debug_console(const char *s, int count)
{
unsigned i;
for (i = 0; i < count; i++) {
if (*s == 10)
prom_printf("%c", 13);
prom_printf("%c", *s++);
}
}
#endif
/*
* ------------------------------------------------------------
* dz_in () and dz_out ()
*
* These routines are used to access the registers of the DZ
* chip, hiding relocation differences between implementation.
* ------------------------------------------------------------
*/
static inline unsigned short dz_in(struct dz_port *dport, unsigned offset)
{
volatile unsigned short *addr =
(volatile unsigned short *) (dport->port.membase + offset);
return *addr;
}
static inline void dz_out(struct dz_port *dport, unsigned offset,
unsigned short value)
{
volatile unsigned short *addr =
(volatile unsigned short *) (dport->port.membase + offset);
*addr = value;
}
/*
* ------------------------------------------------------------
* rs_stop () and rs_start ()
*
* These routines are called before setting or resetting
* tty->stopped. They enable or disable transmitter interrupts,
* as necessary.
* ------------------------------------------------------------
*/
static void dz_stop_tx(struct uart_port *uport)
{
struct dz_port *dport = (struct dz_port *)uport;
unsigned short tmp, mask = 1 << dport->port.line;
unsigned long flags;
spin_lock_irqsave(&dport->port.lock, flags);
tmp = dz_in(dport, DZ_TCR); /* read the TX flag */
tmp &= ~mask; /* clear the TX flag */
dz_out(dport, DZ_TCR, tmp);
spin_unlock_irqrestore(&dport->port.lock, flags);
}
static void dz_start_tx(struct uart_port *uport)
{
struct dz_port *dport = (struct dz_port *)uport;
unsigned short tmp, mask = 1 << dport->port.line;
unsigned long flags;
spin_lock_irqsave(&dport->port.lock, flags);
tmp = dz_in(dport, DZ_TCR); /* read the TX flag */
tmp |= mask; /* set the TX flag */
dz_out(dport, DZ_TCR, tmp);
spin_unlock_irqrestore(&dport->port.lock, flags);
}
static void dz_stop_rx(struct uart_port *uport)
{
struct dz_port *dport = (struct dz_port *)uport;
unsigned long flags;
spin_lock_irqsave(&dport->port.lock, flags);
dport->cflag &= ~DZ_CREAD;
dz_out(dport, DZ_LPR, dport->cflag);
spin_unlock_irqrestore(&dport->port.lock, flags);
}
static void dz_enable_ms(struct uart_port *port)
{
/* nothing to do */
}
/*
* ------------------------------------------------------------
* Here starts the interrupt handling routines. All of the
* following subroutines are declared as inline and are folded
* into dz_interrupt. They were separated out for readability's
* sake.
*
* Note: rs_interrupt() is a "fast" interrupt, which means that it
* runs with interrupts turned off. People who may want to modify
* rs_interrupt() should try to keep the interrupt handler as fast as
* possible. After you are done making modifications, it is not a bad
* idea to do:
*
* make drivers/serial/dz.s
*
* and look at the resulting assemble code in dz.s.
*
* ------------------------------------------------------------
*/
/*
* ------------------------------------------------------------
* receive_char ()
*
* This routine deals with inputs from any lines.
* ------------------------------------------------------------
*/
static inline void dz_receive_chars(struct dz_port *dport)
{
struct tty_struct *tty = NULL;
struct uart_icount *icount;
int ignore = 0;
unsigned short status, tmp;
unsigned char ch, flag;
/* this code is going to be a problem...
the call to tty_flip_buffer is going to need
to be rethought...
*/
do {
status = dz_in(dport, DZ_RBUF);
/* punt so we don't get duplicate characters */
if (!(status & DZ_DVAL))
goto ignore_char;
ch = UCHAR(status); /* grab the char */
flag = TTY_NORMAL;
#if 0
if (info->is_console) {
if (ch == 0)
return; /* it's a break ... */
}
#endif
tty = dport->port.info->tty;/* now tty points to the proper dev */
icount = &dport->port.icount;
if (!tty)
break;
if (tty->flip.count >= TTY_FLIPBUF_SIZE)
break;
icount->rx++;
/* keep track of the statistics */
if (status & (DZ_OERR | DZ_FERR | DZ_PERR)) {
if (status & DZ_PERR) /* parity error */
icount->parity++;
else if (status & DZ_FERR) /* frame error */
icount->frame++;
if (status & DZ_OERR) /* overrun error */
icount->overrun++;
/* check to see if we should ignore the character
and mask off conditions that should be ignored
*/
if (status & dport->port.ignore_status_mask) {
if (++ignore > 100)
break;
goto ignore_char;
}
/* mask off the error conditions we want to ignore */
tmp = status & dport->port.read_status_mask;
if (tmp & DZ_PERR) {
flag = TTY_PARITY;
#ifdef DEBUG_DZ
debug_console("PERR\n", 5);
#endif
} else if (tmp & DZ_FERR) {
flag = TTY_FRAME;
#ifdef DEBUG_DZ
debug_console("FERR\n", 5);
#endif
}
if (tmp & DZ_OERR) {
#ifdef DEBUG_DZ
debug_console("OERR\n", 5);
#endif
tty_insert_flip_char(tty, ch, flag);
ch = 0;
flag = TTY_OVERRUN;
}
}
tty_insert_flip_char(tty, ch, flag);
ignore_char:
} while (status & DZ_DVAL);
if (tty)
tty_flip_buffer_push(tty);
}
/*
* ------------------------------------------------------------
* transmit_char ()
*
* This routine deals with outputs to any lines.
* ------------------------------------------------------------
*/
static inline void dz_transmit_chars(struct dz_port *dport)
{
struct circ_buf *xmit = &dport->port.info->xmit;
unsigned char tmp;
if (dport->port.x_char) { /* XON/XOFF chars */
dz_out(dport, DZ_TDR, dport->port.x_char);
dport->port.icount.tx++;
dport->port.x_char = 0;
return;
}
/* if nothing to do or stopped or hardware stopped */
if (uart_circ_empty(xmit) || uart_tx_stopped(&dport->port)) {
dz_stop_tx(&dport->port);
return;
}
/*
* if something to do ... (rember the dz has no output fifo so we go
* one char at a time :-<
*/
tmp = xmit->buf[xmit->tail];
xmit->tail = (xmit->tail + 1) & (DZ_XMIT_SIZE - 1);
dz_out(dport, DZ_TDR, tmp);
dport->port.icount.tx++;
if (uart_circ_chars_pending(xmit) < DZ_WAKEUP_CHARS)
uart_write_wakeup(&dport->port);
/* Are we done */
if (uart_circ_empty(xmit))
dz_stop_tx(&dport->port);
}
/*
* ------------------------------------------------------------
* check_modem_status ()
*
* Only valid for the MODEM line duh !
* ------------------------------------------------------------
*/
static inline void check_modem_status(struct dz_port *dport)
{
unsigned short status;
/* if not ne modem line just return */
if (dport->port.line != DZ_MODEM)
return;
status = dz_in(dport, DZ_MSR);
/* it's easy, since DSR2 is the only bit in the register */
if (status)
dport->port.icount.dsr++;
}
/*
* ------------------------------------------------------------
* dz_interrupt ()
*
* this is the main interrupt routine for the DZ chip.
* It deals with the multiple ports.
* ------------------------------------------------------------
*/
static irqreturn_t dz_interrupt(int irq, void *dev, struct pt_regs *regs)
{
struct dz_port *dport;
unsigned short status;
/* get the reason why we just got an irq */
status = dz_in((struct dz_port *)dev, DZ_CSR);
dport = &dz_ports[LINE(status)];
if (status & DZ_RDONE)
dz_receive_chars(dport);
if (status & DZ_TRDY)
dz_transmit_chars(dport);
/* FIXME: what about check modem status??? --rmk */
return IRQ_HANDLED;
}
/*
* -------------------------------------------------------------------
* Here ends the DZ interrupt routines.
* -------------------------------------------------------------------
*/
static unsigned int dz_get_mctrl(struct uart_port *uport)
{
struct dz_port *dport = (struct dz_port *)uport;
unsigned int mctrl = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
if (dport->port.line == DZ_MODEM) {
/*
* CHECKME: This is a guess from the other code... --rmk
*/
if (dz_in(dport, DZ_MSR) & DZ_MODEM_DSR)
mctrl &= ~TIOCM_DSR;
}
return mctrl;
}
static void dz_set_mctrl(struct uart_port *uport, unsigned int mctrl)
{
struct dz_port *dport = (struct dz_port *)uport;
unsigned short tmp;
if (dport->port.line == DZ_MODEM) {
tmp = dz_in(dport, DZ_TCR);
if (mctrl & TIOCM_DTR)
tmp &= ~DZ_MODEM_DTR;
else
tmp |= DZ_MODEM_DTR;
dz_out(dport, DZ_TCR, tmp);
}
}
/*
* -------------------------------------------------------------------
* startup ()
*
* various initialization tasks
* -------------------------------------------------------------------
*/
static int dz_startup(struct uart_port *uport)
{
struct dz_port *dport = (struct dz_port *)uport;
unsigned long flags;
unsigned short tmp;
/* The dz lines for the mouse/keyboard must be
* opened using their respective drivers.
*/
if ((dport->port.line == DZ_KEYBOARD) ||
(dport->port.line == DZ_MOUSE))
return -ENODEV;
spin_lock_irqsave(&dport->port.lock, flags);
/* enable the interrupt and the scanning */
tmp = dz_in(dport, DZ_CSR);
tmp |= DZ_RIE | DZ_TIE | DZ_MSE;
dz_out(dport, DZ_CSR, tmp);
spin_unlock_irqrestore(&dport->port.lock, flags);
return 0;
}
/*
* -------------------------------------------------------------------
* shutdown ()
*
* This routine will shutdown a serial port; interrupts are disabled, and
* DTR is dropped if the hangup on close termio flag is on.
* -------------------------------------------------------------------
*/
static void dz_shutdown(struct uart_port *uport)
{
dz_stop_tx(uport);
}
/*
* get_lsr_info - get line status register info
*
* Purpose: Let user call ioctl() to get info when the UART physically
* is emptied. On bus types like RS485, the transmitter must
* release the bus after transmitting. This must be done when
* the transmit shift register is empty, not be done when the
* transmit holding register is empty. This functionality
* allows an RS485 driver to be written in user space.
*/
static unsigned int dz_tx_empty(struct uart_port *uport)
{
struct dz_port *dport = (struct dz_port *)uport;
unsigned short status = dz_in(dport, DZ_LPR);
/* FIXME: this appears to be obviously broken --rmk. */
return status ? TIOCSER_TEMT : 0;
}
static void dz_break_ctl(struct uart_port *uport, int break_state)
{
struct dz_port *dport = (struct dz_port *)uport;
unsigned long flags;
unsigned short tmp, mask = 1 << uport->line;
spin_lock_irqsave(&uport->lock, flags);
tmp = dz_in(dport, DZ_TCR);
if (break_state)
tmp |= mask;
else
tmp &= ~mask;
dz_out(dport, DZ_TCR, tmp);
spin_unlock_irqrestore(&uport->lock, flags);
}
static void dz_set_termios(struct uart_port *uport, struct termios *termios,
struct termios *old_termios)
{
struct dz_port *dport = (struct dz_port *)uport;
unsigned long flags;
unsigned int cflag, baud;
cflag = dport->port.line;
switch (termios->c_cflag & CSIZE) {
case CS5:
cflag |= DZ_CS5;
break;
case CS6:
cflag |= DZ_CS6;
break;
case CS7:
cflag |= DZ_CS7;
break;
case CS8:
default:
cflag |= DZ_CS8;
}
if (termios->c_cflag & CSTOPB)
cflag |= DZ_CSTOPB;
if (termios->c_cflag & PARENB)
cflag |= DZ_PARENB;
if (termios->c_cflag & PARODD)
cflag |= DZ_PARODD;
baud = uart_get_baud_rate(uport, termios, old_termios, 50, 9600);
switch (baud) {
case 50:
cflag |= DZ_B50;
break;
case 75:
cflag |= DZ_B75;
break;
case 110:
cflag |= DZ_B110;
break;
case 134:
cflag |= DZ_B134;
break;
case 150:
cflag |= DZ_B150;
break;
case 300:
cflag |= DZ_B300;
break;
case 600:
cflag |= DZ_B600;
break;
case 1200:
cflag |= DZ_B1200;
break;
case 1800:
cflag |= DZ_B1800;
break;
case 2000:
cflag |= DZ_B2000;
break;
case 2400:
cflag |= DZ_B2400;
break;
case 3600:
cflag |= DZ_B3600;
break;
case 4800:
cflag |= DZ_B4800;
break;
case 7200:
cflag |= DZ_B7200;
break;
case 9600:
default:
cflag |= DZ_B9600;
}
if (termios->c_cflag & CREAD)
cflag |= DZ_RXENAB;
spin_lock_irqsave(&dport->port.lock, flags);
dz_out(dport, DZ_LPR, cflag);
dport->cflag = cflag;
/* setup accept flag */
dport->port.read_status_mask = DZ_OERR;
if (termios->c_iflag & INPCK)
dport->port.read_status_mask |= DZ_FERR | DZ_PERR;
/* characters to ignore */
uport->ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
dport->port.ignore_status_mask |= DZ_FERR | DZ_PERR;
spin_unlock_irqrestore(&dport->port.lock, flags);
}
static const char *dz_type(struct uart_port *port)
{
return "DZ";
}
static void dz_release_port(struct uart_port *port)
{
/* nothing to do */
}
static int dz_request_port(struct uart_port *port)
{
return 0;
}
static void dz_config_port(struct uart_port *port, int flags)
{
if (flags & UART_CONFIG_TYPE)
port->type = PORT_DZ;
}
/*
* verify the new serial_struct (for TIOCSSERIAL).
*/
static int dz_verify_port(struct uart_port *port, struct serial_struct *ser)
{
int ret = 0;
if (ser->type != PORT_UNKNOWN && ser->type != PORT_DZ)
ret = -EINVAL;
if (ser->irq != port->irq)
ret = -EINVAL;
return ret;
}
static struct uart_ops dz_ops = {
.tx_empty = dz_tx_empty,
.get_mctrl = dz_get_mctrl,
.set_mctrl = dz_set_mctrl,
.stop_tx = dz_stop_tx,
.start_tx = dz_start_tx,
.stop_rx = dz_stop_rx,
.enable_ms = dz_enable_ms,
.break_ctl = dz_break_ctl,
.startup = dz_startup,
.shutdown = dz_shutdown,
.set_termios = dz_set_termios,
.type = dz_type,
.release_port = dz_release_port,
.request_port = dz_request_port,
.config_port = dz_config_port,
.verify_port = dz_verify_port,
};
static void __init dz_init_ports(void)
{
static int first = 1;
struct dz_port *dport;
unsigned long base;
int i;
if (!first)
return;
first = 0;
if (mips_machtype == MACH_DS23100 ||
mips_machtype == MACH_DS5100)
base = (unsigned long) KN01_DZ11_BASE;
else
base = (unsigned long) KN02_DZ11_BASE;
for (i = 0, dport = dz_ports; i < DZ_NB_PORT; i++, dport++) {
spin_lock_init(&dport->port.lock);
dport->port.membase = (char *) base;
dport->port.iotype = SERIAL_IO_PORT;
dport->port.irq = dec_interrupt[DEC_IRQ_DZ11];
dport->port.line = i;
dport->port.fifosize = 1;
dport->port.ops = &dz_ops;
dport->port.flags = UPF_BOOT_AUTOCONF;
}
}
static void dz_reset(struct dz_port *dport)
{
dz_out(dport, DZ_CSR, DZ_CLR);
while (dz_in(dport, DZ_CSR) & DZ_CLR);
/* FIXME: cpu_relax? */
iob();
/* enable scanning */
dz_out(dport, DZ_CSR, DZ_MSE);
}
#ifdef CONFIG_SERIAL_DZ_CONSOLE
static void dz_console_put_char(struct dz_port *dport, unsigned char ch)
{
unsigned long flags;
int loops = 2500;
unsigned short tmp = ch;
/* this code sends stuff out to serial device - spinning its
wheels and waiting. */
spin_lock_irqsave(&dport->port.lock, flags);
/* spin our wheels */
while (((dz_in(dport, DZ_CSR) & DZ_TRDY) != DZ_TRDY) && loops--)
/* FIXME: cpu_relax, udelay? --rmk */
;
/* Actually transmit the character. */
dz_out(dport, DZ_TDR, tmp);
spin_unlock_irqrestore(&dport->port.lock, flags);
}
/*
* -------------------------------------------------------------------
* dz_console_print ()
*
* dz_console_print is registered for printk.
* The console must be locked when we get here.
* -------------------------------------------------------------------
*/
static void dz_console_print(struct console *cons,
const char *str,
unsigned int count)
{
struct dz_port *dport = &dz_ports[CONSOLE_LINE];
#ifdef DEBUG_DZ
prom_printf((char *) str);
#endif
while (count--) {
if (*str == '\n')
dz_console_put_char(dport, '\r');
dz_console_put_char(dport, *str++);
}
}
static int __init dz_console_setup(struct console *co, char *options)
{
struct dz_port *dport = &dz_ports[CONSOLE_LINE];
int baud = 9600;
int bits = 8;
int parity = 'n';
int flow = 'n';
int ret;
unsigned short mask, tmp;
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
dz_reset(dport);
ret = uart_set_options(&dport->port, co, baud, parity, bits, flow);
if (ret == 0) {
mask = 1 << dport->port.line;
tmp = dz_in(dport, DZ_TCR); /* read the TX flag */
if (!(tmp & mask)) {
tmp |= mask; /* set the TX flag */
dz_out(dport, DZ_TCR, tmp);
}
}
return ret;
}
static struct console dz_sercons =
{
.name = "ttyS",
.write = dz_console_print,
.device = uart_console_device,
.setup = dz_console_setup,
.flags = CON_CONSDEV | CON_PRINTBUFFER,
.index = CONSOLE_LINE,
};
void __init dz_serial_console_init(void)
{
dz_init_ports();
register_console(&dz_sercons);
}
#define SERIAL_DZ_CONSOLE &dz_sercons
#else
#define SERIAL_DZ_CONSOLE NULL
#endif /* CONFIG_SERIAL_DZ_CONSOLE */
static struct uart_driver dz_reg = {
.owner = THIS_MODULE,
.driver_name = "serial",
#ifdef CONFIG_DEVFS
.dev_name = "tts/%d",
#else
.dev_name = "ttyS%d",
#endif
.major = TTY_MAJOR,
.minor = 64,
.nr = DZ_NB_PORT,
.cons = SERIAL_DZ_CONSOLE,
};
int __init dz_init(void)
{
unsigned long flags;
int ret, i;
printk("%s%s\n", dz_name, dz_version);
dz_init_ports();
save_flags(flags);
cli();
#ifndef CONFIG_SERIAL_DZ_CONSOLE
/* reset the chip */
dz_reset(&dz_ports[0]);
#endif
/* order matters here... the trick is that flags
is updated... in request_irq - to immediatedly obliterate
it is unwise. */
restore_flags(flags);
if (request_irq(dz_ports[0].port.irq, dz_interrupt,
SA_INTERRUPT, "DZ", &dz_ports[0]))
panic("Unable to register DZ interrupt");
ret = uart_register_driver(&dz_reg);
if (ret != 0)
return ret;
for (i = 0; i < DZ_NB_PORT; i++)
uart_add_one_port(&dz_reg, &dz_ports[i].port);
return ret;
}
MODULE_DESCRIPTION("DECstation DZ serial driver");
MODULE_LICENSE("GPL");
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