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linux/drivers/serial/68328serial.c
Alan Cox 33f0f88f1c [PATCH] TTY layer buffering revamp 
The API and code have been through various bits of initial review by
serial driver people but they definitely need to live somewhere for a
while so the unconverted drivers can get knocked into shape, existing
drivers that have been updated can be better tuned and bugs whacked out.

This replaces the tty flip buffers with kmalloc objects in rings. In the
normal situation for an IRQ driven serial port at typical speeds the
behaviour is pretty much the same, two buffers end up allocated and the
kernel cycles between them as before.

When there are delays or at high speed we now behave far better as the
buffer pool can grow a bit rather than lose characters. This also means
that we can operate at higher speeds reliably.

For drivers that receive characters in blocks (DMA based, USB and
especially virtualisation) the layer allows a lot of driver specific
code that works around the tty layer with private secondary queues to be
removed. The IBM folks need this sort of layer, the smart serial port
people do, the virtualisers do (because a virtualised tty typically
operates at infinite speed rather than emulating 9600 baud).

Finally many drivers had invalid and unsafe attempts to avoid buffer
overflows by directly invoking tty methods extracted out of the innards
of work queue structs. These are no longer needed and all go away. That
fixes various random hangs with serial ports on overflow.

The other change in here is to optimise the receive_room path that is
used by some callers. It turns out that only one ldisc uses receive room
except asa constant and it updates it far far less than the value is
read. We thus make it a variable not a function call.

I expect the code to contain bugs due to the size alone but I'll be
watching and squashing them and feeding out new patches as it goes.

Because the buffers now dynamically expand you should only run out of
buffering when the kernel runs out of memory for real.  That means a lot of
the horrible hacks high performance drivers used to do just aren't needed any
more.

Description:

tty_insert_flip_char is an old API and continues to work as before, as does
tty_flip_buffer_push() [this is why many drivers dont need modification].  It
does now also return the number of chars inserted

There are also

tty_buffer_request_room(tty, len)

which asks for a buffer block of the length requested and returns the space
found.  This improves efficiency with hardware that knows how much to
transfer.

and tty_insert_flip_string_flags(tty, str, flags, len)

to insert a string of characters and flags

For a smart interface the usual code is

    len = tty_request_buffer_room(tty, amount_hardware_says);
    tty_insert_flip_string(tty, buffer_from_card, len);

More description!

At the moment tty buffers are attached directly to the tty.  This is causing a
lot of the problems related to tty layer locking, also problems at high speed
and also with bursty data (such as occurs in virtualised environments)

I'm working on ripping out the flip buffers and replacing them with a pool of
dynamically allocated buffers.  This allows both for old style "byte I/O"
devices and also helps virtualisation and smart devices where large blocks of
data suddenely materialise and need storing.

So far so good.  Lots of drivers reference tty->flip.*.  Several of them also
call directly and unsafely into function pointers it provides.  This will all
break.  Most drivers can use tty_insert_flip_char which can be kept as an API
but others need more.

At the moment I've added the following interfaces, if people think more will
be needed now is a good time to say

 int tty_buffer_request_room(tty, size)

Try and ensure at least size bytes are available, returns actual room (may be
zero).  At the moment it just uses the flipbuf space but that will change.
Repeated calls without characters being added are not cumulative.  (ie if you
call it with 1, 1, 1, and then 4 you'll have four characters of space.  The
other functions will also try and grow buffers in future but this will be a
more efficient way when you know block sizes.

 int tty_insert_flip_char(tty, ch, flag)

As before insert a character if there is room.  Now returns 1 for success, 0
for failure.

 int tty_insert_flip_string(tty, str, len)

Insert a block of non error characters.  Returns the number inserted.

 int tty_prepare_flip_string(tty, strptr, len)

Adjust the buffer to allow len characters to be added.  Returns a buffer
pointer in strptr and the length available.  This allows for hardware that
needs to use functions like insl or mencpy_fromio.

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: John Hawkes <hawkes@sgi.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10 08:01:59 -08:00

1595 lines
37 KiB
C
Raw Blame History

/* 68328serial.c: Serial port driver for 68328 microcontroller
*
* Copyright (C) 1995 David S. Miller <davem@caip.rutgers.edu>
* Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com>
* Copyright (C) 1998, 1999 D. Jeff Dionne <jeff@uclinux.org>
* Copyright (C) 1999 Vladimir Gurevich <vgurevic@cisco.com>
* Copyright (C) 2002-2003 David McCullough <davidm@snapgear.com>
* Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com>
*
* VZ Support/Fixes Evan Stawnyczy <e@lineo.ca>
* Multiple UART support Daniel Potts <danielp@cse.unsw.edu.au>
* Power management support Daniel Potts <danielp@cse.unsw.edu.au>
* VZ Second Serial Port enable Phil Wilshire
* 2.4/2.5 port David McCullough
*/
#include <asm/dbg.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/config.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/console.h>
#include <linux/reboot.h>
#include <linux/keyboard.h>
#include <linux/init.h>
#include <linux/pm.h>
#include <linux/pm_legacy.h>
#include <linux/bitops.h>
#include <linux/delay.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/delay.h>
#include <asm/uaccess.h>
/* (es) */
/* note: perhaps we can murge these files, so that you can just
* define 1 of them, and they can sort that out for themselves
*/
#if defined(CONFIG_M68EZ328)
#include <asm/MC68EZ328.h>
#else
#if defined(CONFIG_M68VZ328)
#include <asm/MC68VZ328.h>
#else
#include <asm/MC68328.h>
#endif /* CONFIG_M68VZ328 */
#endif /* CONFIG_M68EZ328 */
#include "68328serial.h"
/* Turn off usage of real serial interrupt code, to "support" Copilot */
#ifdef CONFIG_XCOPILOT_BUGS
#undef USE_INTS
#else
#define USE_INTS
#endif
static struct m68k_serial m68k_soft[NR_PORTS];
struct m68k_serial *IRQ_ports[NR_IRQS];
static unsigned int uart_irqs[NR_PORTS] = UART_IRQ_DEFNS;
/* multiple ports are contiguous in memory */
m68328_uart *uart_addr = (m68328_uart *)USTCNT_ADDR;
struct tty_struct m68k_ttys;
struct m68k_serial *m68k_consinfo = 0;
#define M68K_CLOCK (16667000) /* FIXME: 16MHz is likely wrong */
#ifdef CONFIG_CONSOLE
extern wait_queue_head_t keypress_wait;
#endif
struct tty_driver *serial_driver;
/* serial subtype definitions */
#define SERIAL_TYPE_NORMAL 1
/* number of characters left in xmit buffer before we ask for more */
#define WAKEUP_CHARS 256
/* Debugging... DEBUG_INTR is bad to use when one of the zs
* lines is your console ;(
*/
#undef SERIAL_DEBUG_INTR
#undef SERIAL_DEBUG_OPEN
#undef SERIAL_DEBUG_FLOW
#define RS_ISR_PASS_LIMIT 256
#define _INLINE_ inline
static void change_speed(struct m68k_serial *info);
/*
* Setup for console. Argument comes from the boot command line.
*/
#if defined(CONFIG_M68EZ328ADS) || defined(CONFIG_ALMA_ANS) || defined(CONFIG_DRAGONIXVZ)
#define CONSOLE_BAUD_RATE 115200
#define DEFAULT_CBAUD B115200
#else
/* (es) */
/* note: this is messy, but it works, again, perhaps defined somewhere else?*/
#ifdef CONFIG_M68VZ328
#define CONSOLE_BAUD_RATE 19200
#define DEFAULT_CBAUD B19200
#endif
/* (/es) */
#endif
#ifndef CONSOLE_BAUD_RATE
#define CONSOLE_BAUD_RATE 9600
#define DEFAULT_CBAUD B9600
#endif
static int m68328_console_initted = 0;
static int m68328_console_baud = CONSOLE_BAUD_RATE;
static int m68328_console_cbaud = DEFAULT_CBAUD;
/*
* tmp_buf is used as a temporary buffer by serial_write. We need to
* lock it in case the memcpy_fromfs blocks while swapping in a page,
* and some other program tries to do a serial write at the same time.
* Since the lock will only come under contention when the system is
* swapping and available memory is low, it makes sense to share one
* buffer across all the serial ports, since it significantly saves
* memory if large numbers of serial ports are open.
*/
static unsigned char tmp_buf[SERIAL_XMIT_SIZE]; /* This is cheating */
DECLARE_MUTEX(tmp_buf_sem);
static inline int serial_paranoia_check(struct m68k_serial *info,
char *name, const char *routine)
{
#ifdef SERIAL_PARANOIA_CHECK
static const char *badmagic =
"Warning: bad magic number for serial struct %s in %s\n";
static const char *badinfo =
"Warning: null m68k_serial for %s in %s\n";
if (!info) {
printk(badinfo, name, routine);
return 1;
}
if (info->magic != SERIAL_MAGIC) {
printk(badmagic, name, routine);
return 1;
}
#endif
return 0;
}
/*
* This is used to figure out the divisor speeds and the timeouts
*/
static int baud_table[] = {
0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
9600, 19200, 38400, 57600, 115200, 0 };
#define BAUD_TABLE_SIZE (sizeof(baud_table)/sizeof(baud_table[0]))
/* Sets or clears DTR/RTS on the requested line */
static inline void m68k_rtsdtr(struct m68k_serial *ss, int set)
{
if (set) {
/* set the RTS/CTS line */
} else {
/* clear it */
}
return;
}
/* Utility routines */
static inline int get_baud(struct m68k_serial *ss)
{
unsigned long result = 115200;
unsigned short int baud = uart_addr[ss->line].ubaud;
if (GET_FIELD(baud, UBAUD_PRESCALER) == 0x38) result = 38400;
result >>= GET_FIELD(baud, UBAUD_DIVIDE);
return result;
}
/*
* ------------------------------------------------------------
* rs_stop() and rs_start()
*
* This routines are called before setting or resetting tty->stopped.
* They enable or disable transmitter interrupts, as necessary.
* ------------------------------------------------------------
*/
static void rs_stop(struct tty_struct *tty)
{
struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
m68328_uart *uart = &uart_addr[info->line];
unsigned long flags;
if (serial_paranoia_check(info, tty->name, "rs_stop"))
return;
save_flags(flags); cli();
uart->ustcnt &= ~USTCNT_TXEN;
restore_flags(flags);
}
static void rs_put_char(char ch)
{
int flags, loops = 0;
save_flags(flags); cli();
while (!(UTX & UTX_TX_AVAIL) && (loops < 1000)) {
loops++;
udelay(5);
}
UTX_TXDATA = ch;
udelay(5);
restore_flags(flags);
}
static void rs_start(struct tty_struct *tty)
{
struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
m68328_uart *uart = &uart_addr[info->line];
unsigned long flags;
if (serial_paranoia_check(info, tty->name, "rs_start"))
return;
save_flags(flags); cli();
if (info->xmit_cnt && info->xmit_buf && !(uart->ustcnt & USTCNT_TXEN)) {
#ifdef USE_INTS
uart->ustcnt |= USTCNT_TXEN | USTCNT_TX_INTR_MASK;
#else
uart->ustcnt |= USTCNT_TXEN;
#endif
}
restore_flags(flags);
}
/* Drop into either the boot monitor or kadb upon receiving a break
* from keyboard/console input.
*/
static void batten_down_hatches(void)
{
/* Drop into the debugger */
}
static _INLINE_ void status_handle(struct m68k_serial *info, unsigned short status)
{
#if 0
if(status & DCD) {
if((info->tty->termios->c_cflag & CRTSCTS) &&
((info->curregs[3] & AUTO_ENAB)==0)) {
info->curregs[3] |= AUTO_ENAB;
info->pendregs[3] |= AUTO_ENAB;
write_zsreg(info->m68k_channel, 3, info->curregs[3]);
}
} else {
if((info->curregs[3] & AUTO_ENAB)) {
info->curregs[3] &= ~AUTO_ENAB;
info->pendregs[3] &= ~AUTO_ENAB;
write_zsreg(info->m68k_channel, 3, info->curregs[3]);
}
}
#endif
/* If this is console input and this is a
* 'break asserted' status change interrupt
* see if we can drop into the debugger
*/
if((status & URX_BREAK) && info->break_abort)
batten_down_hatches();
return;
}
static _INLINE_ void receive_chars(struct m68k_serial *info, struct pt_regs *regs, unsigned short rx)
{
struct tty_struct *tty = info->tty;
m68328_uart *uart = &uart_addr[info->line];
unsigned char ch, flag;
/*
* This do { } while() loop will get ALL chars out of Rx FIFO
*/
#ifndef CONFIG_XCOPILOT_BUGS
do {
#endif
ch = GET_FIELD(rx, URX_RXDATA);
if(info->is_cons) {
if(URX_BREAK & rx) { /* whee, break received */
status_handle(info, rx);
return;
#ifdef CONFIG_MAGIC_SYSRQ
} else if (ch == 0x10) { /* ^P */
show_state();
show_free_areas();
show_buffers();
/* show_net_buffers(); */
return;
} else if (ch == 0x12) { /* ^R */
emergency_restart();
return;
#endif /* CONFIG_MAGIC_SYSRQ */
}
/* It is a 'keyboard interrupt' ;-) */
#ifdef CONFIG_CONSOLE
wake_up(&keypress_wait);
#endif
}
if(!tty)
goto clear_and_exit;
/*
* Make sure that we do not overflow the buffer
*/
if (tty_request_buffer_room(tty, 1) == 0) {
schedule_work(&tty->flip.work);
return;
}
flag = TTY_NORMAL;
if(rx & URX_PARITY_ERROR) {
flag = TTY_PARITY;
status_handle(info, rx);
} else if(rx & URX_OVRUN) {
flag = TTY_OVERRUN;
status_handle(info, rx);
} else if(rx & URX_FRAME_ERROR) {
flag = TTY_FRAME;
status_handle(info, rx);
}
tty_insert_flip_char(tty, ch, flag);
#ifndef CONFIG_XCOPILOT_BUGS
} while((rx = uart->urx.w) & URX_DATA_READY);
#endif
schedule_work(&tty->flip.work);
clear_and_exit:
return;
}
static _INLINE_ void transmit_chars(struct m68k_serial *info)
{
m68328_uart *uart = &uart_addr[info->line];
if (info->x_char) {
/* Send next char */
uart->utx.b.txdata = info->x_char;
info->x_char = 0;
goto clear_and_return;
}
if((info->xmit_cnt <= 0) || info->tty->stopped) {
/* That's peculiar... TX ints off */
uart->ustcnt &= ~USTCNT_TX_INTR_MASK;
goto clear_and_return;
}
/* Send char */
uart->utx.b.txdata = info->xmit_buf[info->xmit_tail++];
info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
info->xmit_cnt--;
if (info->xmit_cnt < WAKEUP_CHARS)
schedule_work(&info->tqueue);
if(info->xmit_cnt <= 0) {
/* All done for now... TX ints off */
uart->ustcnt &= ~USTCNT_TX_INTR_MASK;
goto clear_and_return;
}
clear_and_return:
/* Clear interrupt (should be auto)*/
return;
}
/*
* This is the serial driver's generic interrupt routine
*/
irqreturn_t rs_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
struct m68k_serial * info;
m68328_uart *uart;
unsigned short rx;
unsigned short tx;
info = IRQ_ports[irq];
if(!info)
return IRQ_NONE;
uart = &uart_addr[info->line];
rx = uart->urx.w;
#ifdef USE_INTS
tx = uart->utx.w;
if (rx & URX_DATA_READY) receive_chars(info, regs, rx);
if (tx & UTX_TX_AVAIL) transmit_chars(info);
#else
receive_chars(info, regs, rx);
#endif
return IRQ_HANDLED;
}
static void do_softint(void *private)
{
struct m68k_serial *info = (struct m68k_serial *) private;
struct tty_struct *tty;
tty = info->tty;
if (!tty)
return;
#if 0
if (clear_bit(RS_EVENT_WRITE_WAKEUP, &info->event)) {
tty_wakeup(tty);
}
#endif
}
/*
* This routine is called from the scheduler tqueue when the interrupt
* routine has signalled that a hangup has occurred. The path of
* hangup processing is:
*
* serial interrupt routine -> (scheduler tqueue) ->
* do_serial_hangup() -> tty->hangup() -> rs_hangup()
*
*/
static void do_serial_hangup(void *private)
{
struct m68k_serial *info = (struct m68k_serial *) private;
struct tty_struct *tty;
tty = info->tty;
if (!tty)
return;
tty_hangup(tty);
}
static int startup(struct m68k_serial * info)
{
m68328_uart *uart = &uart_addr[info->line];
unsigned long flags;
if (info->flags & S_INITIALIZED)
return 0;
if (!info->xmit_buf) {
info->xmit_buf = (unsigned char *) __get_free_page(GFP_KERNEL);
if (!info->xmit_buf)
return -ENOMEM;
}
save_flags(flags); cli();
/*
* Clear the FIFO buffers and disable them
* (they will be reenabled in change_speed())
*/
uart->ustcnt = USTCNT_UEN;
info->xmit_fifo_size = 1;
uart->ustcnt = USTCNT_UEN | USTCNT_RXEN | USTCNT_TXEN;
(void)uart->urx.w;
/*
* Finally, enable sequencing and interrupts
*/
#ifdef USE_INTS
uart->ustcnt = USTCNT_UEN | USTCNT_RXEN |
USTCNT_RX_INTR_MASK | USTCNT_TX_INTR_MASK;
#else
uart->ustcnt = USTCNT_UEN | USTCNT_RXEN | USTCNT_RX_INTR_MASK;
#endif
if (info->tty)
clear_bit(TTY_IO_ERROR, &info->tty->flags);
info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
/*
* and set the speed of the serial port
*/
change_speed(info);
info->flags |= S_INITIALIZED;
restore_flags(flags);
return 0;
}
/*
* 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 shutdown(struct m68k_serial * info)
{
m68328_uart *uart = &uart_addr[info->line];
unsigned long flags;
uart->ustcnt = 0; /* All off! */
if (!(info->flags & S_INITIALIZED))
return;
save_flags(flags); cli(); /* Disable interrupts */
if (info->xmit_buf) {
free_page((unsigned long) info->xmit_buf);
info->xmit_buf = 0;
}
if (info->tty)
set_bit(TTY_IO_ERROR, &info->tty->flags);
info->flags &= ~S_INITIALIZED;
restore_flags(flags);
}
struct {
int divisor, prescale;
}
#ifndef CONFIG_M68VZ328
hw_baud_table[18] = {
{0,0}, /* 0 */
{0,0}, /* 50 */
{0,0}, /* 75 */
{0,0}, /* 110 */
{0,0}, /* 134 */
{0,0}, /* 150 */
{0,0}, /* 200 */
{7,0x26}, /* 300 */
{6,0x26}, /* 600 */
{5,0x26}, /* 1200 */
{0,0}, /* 1800 */
{4,0x26}, /* 2400 */
{3,0x26}, /* 4800 */
{2,0x26}, /* 9600 */
{1,0x26}, /* 19200 */
{0,0x26}, /* 38400 */
{1,0x38}, /* 57600 */
{0,0x38}, /* 115200 */
};
#else
hw_baud_table[18] = {
{0,0}, /* 0 */
{0,0}, /* 50 */
{0,0}, /* 75 */
{0,0}, /* 110 */
{0,0}, /* 134 */
{0,0}, /* 150 */
{0,0}, /* 200 */
{0,0}, /* 300 */
{7,0x26}, /* 600 */
{6,0x26}, /* 1200 */
{0,0}, /* 1800 */
{5,0x26}, /* 2400 */
{4,0x26}, /* 4800 */
{3,0x26}, /* 9600 */
{2,0x26}, /* 19200 */
{1,0x26}, /* 38400 */
{0,0x26}, /* 57600 */
{1,0x38}, /* 115200 */
};
#endif
/* rate = 1036800 / ((65 - prescale) * (1<<divider)) */
/*
* This routine is called to set the UART divisor registers to match
* the specified baud rate for a serial port.
*/
static void change_speed(struct m68k_serial *info)
{
m68328_uart *uart = &uart_addr[info->line];
unsigned short port;
unsigned short ustcnt;
unsigned cflag;
int i;
if (!info->tty || !info->tty->termios)
return;
cflag = info->tty->termios->c_cflag;
if (!(port = info->port))
return;
ustcnt = uart->ustcnt;
uart->ustcnt = ustcnt & ~USTCNT_TXEN;
i = cflag & CBAUD;
if (i & CBAUDEX) {
i = (i & ~CBAUDEX) + B38400;
}
info->baud = baud_table[i];
uart->ubaud = PUT_FIELD(UBAUD_DIVIDE, hw_baud_table[i].divisor) |
PUT_FIELD(UBAUD_PRESCALER, hw_baud_table[i].prescale);
ustcnt &= ~(USTCNT_PARITYEN | USTCNT_ODD_EVEN | USTCNT_STOP | USTCNT_8_7);
if ((cflag & CSIZE) == CS8)
ustcnt |= USTCNT_8_7;
if (cflag & CSTOPB)
ustcnt |= USTCNT_STOP;
if (cflag & PARENB)
ustcnt |= USTCNT_PARITYEN;
if (cflag & PARODD)
ustcnt |= USTCNT_ODD_EVEN;
#ifdef CONFIG_SERIAL_68328_RTS_CTS
if (cflag & CRTSCTS) {
uart->utx.w &= ~ UTX_NOCTS;
} else {
uart->utx.w |= UTX_NOCTS;
}
#endif
ustcnt |= USTCNT_TXEN;
uart->ustcnt = ustcnt;
return;
}
/*
* Fair output driver allows a process to speak.
*/
static void rs_fair_output(void)
{
int left; /* Output no more than that */
unsigned long flags;
struct m68k_serial *info = &m68k_soft[0];
char c;
if (info == 0) return;
if (info->xmit_buf == 0) return;
save_flags(flags); cli();
left = info->xmit_cnt;
while (left != 0) {
c = info->xmit_buf[info->xmit_tail];
info->xmit_tail = (info->xmit_tail+1) & (SERIAL_XMIT_SIZE-1);
info->xmit_cnt--;
restore_flags(flags);
rs_put_char(c);
save_flags(flags); cli();
left = min(info->xmit_cnt, left-1);
}
/* Last character is being transmitted now (hopefully). */
udelay(5);
restore_flags(flags);
return;
}
/*
* m68k_console_print is registered for printk.
*/
void console_print_68328(const char *p)
{
char c;
while((c=*(p++)) != 0) {
if(c == '\n')
rs_put_char('\r');
rs_put_char(c);
}
/* Comment this if you want to have a strict interrupt-driven output */
rs_fair_output();
return;
}
static void rs_set_ldisc(struct tty_struct *tty)
{
struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
if (serial_paranoia_check(info, tty->name, "rs_set_ldisc"))
return;
info->is_cons = (tty->termios->c_line == N_TTY);
printk("ttyS%d console mode %s\n", info->line, info->is_cons ? "on" : "off");
}
static void rs_flush_chars(struct tty_struct *tty)
{
struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
m68328_uart *uart = &uart_addr[info->line];
unsigned long flags;
if (serial_paranoia_check(info, tty->name, "rs_flush_chars"))
return;
#ifndef USE_INTS
for(;;) {
#endif
/* Enable transmitter */
save_flags(flags); cli();
if (info->xmit_cnt <= 0 || tty->stopped || tty->hw_stopped ||
!info->xmit_buf) {
restore_flags(flags);
return;
}
#ifdef USE_INTS
uart->ustcnt |= USTCNT_TXEN | USTCNT_TX_INTR_MASK;
#else
uart->ustcnt |= USTCNT_TXEN;
#endif
#ifdef USE_INTS
if (uart->utx.w & UTX_TX_AVAIL) {
#else
if (1) {
#endif
/* Send char */
uart->utx.b.txdata = info->xmit_buf[info->xmit_tail++];
info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
info->xmit_cnt--;
}
#ifndef USE_INTS
while (!(uart->utx.w & UTX_TX_AVAIL)) udelay(5);
}
#endif
restore_flags(flags);
}
extern void console_printn(const char * b, int count);
static int rs_write(struct tty_struct * tty,
const unsigned char *buf, int count)
{
int c, total = 0;
struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
m68328_uart *uart = &uart_addr[info->line];
unsigned long flags;
if (serial_paranoia_check(info, tty->name, "rs_write"))
return 0;
if (!tty || !info->xmit_buf)
return 0;
save_flags(flags);
while (1) {
cli();
c = min_t(int, count, min(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
SERIAL_XMIT_SIZE - info->xmit_head));
if (c <= 0)
break;
memcpy(info->xmit_buf + info->xmit_head, buf, c);
info->xmit_head = (info->xmit_head + c) & (SERIAL_XMIT_SIZE-1);
info->xmit_cnt += c;
restore_flags(flags);
buf += c;
count -= c;
total += c;
}
if (info->xmit_cnt && !tty->stopped && !tty->hw_stopped) {
/* Enable transmitter */
cli();
#ifndef USE_INTS
while(info->xmit_cnt) {
#endif
uart->ustcnt |= USTCNT_TXEN;
#ifdef USE_INTS
uart->ustcnt |= USTCNT_TX_INTR_MASK;
#else
while (!(uart->utx.w & UTX_TX_AVAIL)) udelay(5);
#endif
if (uart->utx.w & UTX_TX_AVAIL) {
uart->utx.b.txdata = info->xmit_buf[info->xmit_tail++];
info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
info->xmit_cnt--;
}
#ifndef USE_INTS
}
#endif
restore_flags(flags);
}
restore_flags(flags);
return total;
}
static int rs_write_room(struct tty_struct *tty)
{
struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
int ret;
if (serial_paranoia_check(info, tty->name, "rs_write_room"))
return 0;
ret = SERIAL_XMIT_SIZE - info->xmit_cnt - 1;
if (ret < 0)
ret = 0;
return ret;
}
static int rs_chars_in_buffer(struct tty_struct *tty)
{
struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
if (serial_paranoia_check(info, tty->name, "rs_chars_in_buffer"))
return 0;
return info->xmit_cnt;
}
static void rs_flush_buffer(struct tty_struct *tty)
{
struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
if (serial_paranoia_check(info, tty->name, "rs_flush_buffer"))
return;
cli();
info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
sti();
tty_wakeup(tty);
}
/*
* ------------------------------------------------------------
* rs_throttle()
*
* This routine is called by the upper-layer tty layer to signal that
* incoming characters should be throttled.
* ------------------------------------------------------------
*/
static void rs_throttle(struct tty_struct * tty)
{
struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
if (serial_paranoia_check(info, tty->name, "rs_throttle"))
return;
if (I_IXOFF(tty))
info->x_char = STOP_CHAR(tty);
/* Turn off RTS line (do this atomic) */
}
static void rs_unthrottle(struct tty_struct * tty)
{
struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
if (serial_paranoia_check(info, tty->name, "rs_unthrottle"))
return;
if (I_IXOFF(tty)) {
if (info->x_char)
info->x_char = 0;
else
info->x_char = START_CHAR(tty);
}
/* Assert RTS line (do this atomic) */
}
/*
* ------------------------------------------------------------
* rs_ioctl() and friends
* ------------------------------------------------------------
*/
static int get_serial_info(struct m68k_serial * info,
struct serial_struct * retinfo)
{
struct serial_struct tmp;
if (!retinfo)
return -EFAULT;
memset(&tmp, 0, sizeof(tmp));
tmp.type = info->type;
tmp.line = info->line;
tmp.port = info->port;
tmp.irq = info->irq;
tmp.flags = info->flags;
tmp.baud_base = info->baud_base;
tmp.close_delay = info->close_delay;
tmp.closing_wait = info->closing_wait;
tmp.custom_divisor = info->custom_divisor;
copy_to_user(retinfo,&tmp,sizeof(*retinfo));
return 0;
}
static int set_serial_info(struct m68k_serial * info,
struct serial_struct * new_info)
{
struct serial_struct new_serial;
struct m68k_serial old_info;
int retval = 0;
if (!new_info)
return -EFAULT;
copy_from_user(&new_serial,new_info,sizeof(new_serial));
old_info = *info;
if (!capable(CAP_SYS_ADMIN)) {
if ((new_serial.baud_base != info->baud_base) ||
(new_serial.type != info->type) ||
(new_serial.close_delay != info->close_delay) ||
((new_serial.flags & ~S_USR_MASK) !=
(info->flags & ~S_USR_MASK)))
return -EPERM;
info->flags = ((info->flags & ~S_USR_MASK) |
(new_serial.flags & S_USR_MASK));
info->custom_divisor = new_serial.custom_divisor;
goto check_and_exit;
}
if (info->count > 1)
return -EBUSY;
/*
* OK, past this point, all the error checking has been done.
* At this point, we start making changes.....
*/
info->baud_base = new_serial.baud_base;
info->flags = ((info->flags & ~S_FLAGS) |
(new_serial.flags & S_FLAGS));
info->type = new_serial.type;
info->close_delay = new_serial.close_delay;
info->closing_wait = new_serial.closing_wait;
check_and_exit:
retval = startup(info);
return retval;
}
/*
* 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 int get_lsr_info(struct m68k_serial * info, unsigned int *value)
{
#ifdef CONFIG_SERIAL_68328_RTS_CTS
m68328_uart *uart = &uart_addr[info->line];
#endif
unsigned char status;
cli();
#ifdef CONFIG_SERIAL_68328_RTS_CTS
status = (uart->utx.w & UTX_CTS_STAT) ? 1 : 0;
#else
status = 0;
#endif
sti();
put_user(status,value);
return 0;
}
/*
* This routine sends a break character out the serial port.
*/
static void send_break(struct m68k_serial * info, unsigned int duration)
{
m68328_uart *uart = &uart_addr[info->line];
unsigned long flags;
if (!info->port)
return;
save_flags(flags);
cli();
#ifdef USE_INTS
uart->utx.w |= UTX_SEND_BREAK;
msleep_interruptible(duration);
uart->utx.w &= ~UTX_SEND_BREAK;
#endif
restore_flags(flags);
}
static int rs_ioctl(struct tty_struct *tty, struct file * file,
unsigned int cmd, unsigned long arg)
{
int error;
struct m68k_serial * info = (struct m68k_serial *)tty->driver_data;
int retval;
if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
return -ENODEV;
if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
(cmd != TIOCSERCONFIG) && (cmd != TIOCSERGWILD) &&
(cmd != TIOCSERSWILD) && (cmd != TIOCSERGSTRUCT)) {
if (tty->flags & (1 << TTY_IO_ERROR))
return -EIO;
}
switch (cmd) {
case TCSBRK: /* SVID version: non-zero arg --> no break */
retval = tty_check_change(tty);
if (retval)
return retval;
tty_wait_until_sent(tty, 0);
if (!arg)
send_break(info, 250); /* 1/4 second */
return 0;
case TCSBRKP: /* support for POSIX tcsendbreak() */
retval = tty_check_change(tty);
if (retval)
return retval;
tty_wait_until_sent(tty, 0);
send_break(info, arg ? arg*(100) : 250);
return 0;
case TIOCGSOFTCAR:
error = put_user(C_CLOCAL(tty) ? 1 : 0,
(unsigned long *) arg);
if (error)
return error;
return 0;
case TIOCSSOFTCAR:
get_user(arg, (unsigned long *) arg);
tty->termios->c_cflag =
((tty->termios->c_cflag & ~CLOCAL) |
(arg ? CLOCAL : 0));
return 0;
case TIOCGSERIAL:
if (access_ok(VERIFY_WRITE, (void *) arg,
sizeof(struct serial_struct)))
return get_serial_info(info,
(struct serial_struct *) arg);
return -EFAULT;
case TIOCSSERIAL:
return set_serial_info(info,
(struct serial_struct *) arg);
case TIOCSERGETLSR: /* Get line status register */
if (access_ok(VERIFY_WRITE, (void *) arg,
sizeof(unsigned int));
return get_lsr_info(info, (unsigned int *) arg);
return -EFAULT;
case TIOCSERGSTRUCT:
if (!access_ok(VERIFY_WRITE, (void *) arg,
sizeof(struct m68k_serial)))
return -EFAULT;
copy_to_user((struct m68k_serial *) arg,
info, sizeof(struct m68k_serial));
return 0;
default:
return -ENOIOCTLCMD;
}
return 0;
}
static void rs_set_termios(struct tty_struct *tty, struct termios *old_termios)
{
struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
if (tty->termios->c_cflag == old_termios->c_cflag)
return;
change_speed(info);
if ((old_termios->c_cflag & CRTSCTS) &&
!(tty->termios->c_cflag & CRTSCTS)) {
tty->hw_stopped = 0;
rs_start(tty);
}
}
/*
* ------------------------------------------------------------
* rs_close()
*
* This routine is called when the serial port gets closed. First, we
* wait for the last remaining data to be sent. Then, we unlink its
* S structure from the interrupt chain if necessary, and we free
* that IRQ if nothing is left in the chain.
* ------------------------------------------------------------
*/
static void rs_close(struct tty_struct *tty, struct file * filp)
{
struct m68k_serial * info = (struct m68k_serial *)tty->driver_data;
m68328_uart *uart = &uart_addr[info->line];
unsigned long flags;
if (!info || serial_paranoia_check(info, tty->name, "rs_close"))
return;
save_flags(flags); cli();
if (tty_hung_up_p(filp)) {
restore_flags(flags);
return;
}
if ((tty->count == 1) && (info->count != 1)) {
/*
* Uh, oh. tty->count is 1, which means that the tty
* structure will be freed. Info->count should always
* be one in these conditions. If it's greater than
* one, we've got real problems, since it means the
* serial port won't be shutdown.
*/
printk("rs_close: bad serial port count; tty->count is 1, "
"info->count is %d\n", info->count);
info->count = 1;
}
if (--info->count < 0) {
printk("rs_close: bad serial port count for ttyS%d: %d\n",
info->line, info->count);
info->count = 0;
}
if (info->count) {
restore_flags(flags);
return;
}
info->flags |= S_CLOSING;
/*
* Now we wait for the transmit buffer to clear; and we notify
* the line discipline to only process XON/XOFF characters.
*/
tty->closing = 1;
if (info->closing_wait != S_CLOSING_WAIT_NONE)
tty_wait_until_sent(tty, info->closing_wait);
/*
* At this point we stop accepting input. To do this, we
* disable the receive line status interrupts, and tell the
* interrupt driver to stop checking the data ready bit in the
* line status register.
*/
uart->ustcnt &= ~USTCNT_RXEN;
uart->ustcnt &= ~(USTCNT_RXEN | USTCNT_RX_INTR_MASK);
shutdown(info);
if (tty->driver->flush_buffer)
tty->driver->flush_buffer(tty);
tty_ldisc_flush(tty);
tty->closing = 0;
info->event = 0;
info->tty = 0;
#warning "This is not and has never been valid so fix it"
#if 0
if (tty->ldisc.num != ldiscs[N_TTY].num) {
if (tty->ldisc.close)
(tty->ldisc.close)(tty);
tty->ldisc = ldiscs[N_TTY];
tty->termios->c_line = N_TTY;
if (tty->ldisc.open)
(tty->ldisc.open)(tty);
}
#endif
if (info->blocked_open) {
if (info->close_delay) {
msleep_interruptible(jiffies_to_msecs(info->close_delay));
}
wake_up_interruptible(&info->open_wait);
}
info->flags &= ~(S_NORMAL_ACTIVE|S_CLOSING);
wake_up_interruptible(&info->close_wait);
restore_flags(flags);
}
/*
* rs_hangup() --- called by tty_hangup() when a hangup is signaled.
*/
void rs_hangup(struct tty_struct *tty)
{
struct m68k_serial * info = (struct m68k_serial *)tty->driver_data;
if (serial_paranoia_check(info, tty->name, "rs_hangup"))
return;
rs_flush_buffer(tty);
shutdown(info);
info->event = 0;
info->count = 0;
info->flags &= ~S_NORMAL_ACTIVE;
info->tty = 0;
wake_up_interruptible(&info->open_wait);
}
/*
* ------------------------------------------------------------
* rs_open() and friends
* ------------------------------------------------------------
*/
static int block_til_ready(struct tty_struct *tty, struct file * filp,
struct m68k_serial *info)
{
DECLARE_WAITQUEUE(wait, current);
int retval;
int do_clocal = 0;
/*
* If the device is in the middle of being closed, then block
* until it's done, and then try again.
*/
if (info->flags & S_CLOSING) {
interruptible_sleep_on(&info->close_wait);
#ifdef SERIAL_DO_RESTART
if (info->flags & S_HUP_NOTIFY)
return -EAGAIN;
else
return -ERESTARTSYS;
#else
return -EAGAIN;
#endif
}
/*
* If non-blocking mode is set, or the port is not enabled,
* then make the check up front and then exit.
*/
if ((filp->f_flags & O_NONBLOCK) ||
(tty->flags & (1 << TTY_IO_ERROR))) {
info->flags |= S_NORMAL_ACTIVE;
return 0;
}
if (tty->termios->c_cflag & CLOCAL)
do_clocal = 1;
/*
* Block waiting for the carrier detect and the line to become
* free (i.e., not in use by the callout). While we are in
* this loop, info->count is dropped by one, so that
* rs_close() knows when to free things. We restore it upon
* exit, either normal or abnormal.
*/
retval = 0;
add_wait_queue(&info->open_wait, &wait);
info->count--;
info->blocked_open++;
while (1) {
cli();
m68k_rtsdtr(info, 1);
sti();
current->state = TASK_INTERRUPTIBLE;
if (tty_hung_up_p(filp) ||
!(info->flags & S_INITIALIZED)) {
#ifdef SERIAL_DO_RESTART
if (info->flags & S_HUP_NOTIFY)
retval = -EAGAIN;
else
retval = -ERESTARTSYS;
#else
retval = -EAGAIN;
#endif
break;
}
if (!(info->flags & S_CLOSING) && do_clocal)
break;
if (signal_pending(current)) {
retval = -ERESTARTSYS;
break;
}
schedule();
}
current->state = TASK_RUNNING;
remove_wait_queue(&info->open_wait, &wait);
if (!tty_hung_up_p(filp))
info->count++;
info->blocked_open--;
if (retval)
return retval;
info->flags |= S_NORMAL_ACTIVE;
return 0;
}
/*
* This routine is called whenever a serial port is opened. It
* enables interrupts for a serial port, linking in its S structure into
* the IRQ chain. It also performs the serial-specific
* initialization for the tty structure.
*/
int rs_open(struct tty_struct *tty, struct file * filp)
{
struct m68k_serial *info;
int retval, line;
line = tty->index;
if (line >= NR_PORTS || line < 0) /* we have exactly one */
return -ENODEV;
info = &m68k_soft[line];
if (serial_paranoia_check(info, tty->name, "rs_open"))
return -ENODEV;
info->count++;
tty->driver_data = info;
info->tty = tty;
/*
* Start up serial port
*/
retval = startup(info);
if (retval)
return retval;
return block_til_ready(tty, filp, info);
}
/* Finally, routines used to initialize the serial driver. */
static void show_serial_version(void)
{
printk("MC68328 serial driver version 1.00\n");
}
#ifdef CONFIG_PM_LEGACY
/* Serial Power management
* The console (currently fixed at line 0) is a special case for power
* management because the kernel is so chatty. The console will be
* explicitly disabled my our power manager as the last minute, so we won't
* mess with it here.
*/
static struct pm_dev *serial_pm[NR_PORTS];
static int serial_pm_callback(struct pm_dev *dev, pm_request_t request, void *data)
{
struct m68k_serial *info = (struct m68k_serial *)dev->data;
if(info == NULL)
return -1;
/* special case for line 0 - pm restores it */
if(info->line == 0)
return 0;
switch (request) {
case PM_SUSPEND:
shutdown(info);
break;
case PM_RESUME:
startup(info);
break;
}
return 0;
}
void shutdown_console(void)
{
struct m68k_serial *info = &m68k_soft[0];
/* HACK: wait a bit for any pending printk's to be dumped */
{
int i = 10000;
while(i--);
}
shutdown(info);
}
void startup_console(void)
{
struct m68k_serial *info = &m68k_soft[0];
startup(info);
}
#endif /* CONFIG_PM_LEGACY */
static struct tty_operations rs_ops = {
.open = rs_open,
.close = rs_close,
.write = rs_write,
.flush_chars = rs_flush_chars,
.write_room = rs_write_room,
.chars_in_buffer = rs_chars_in_buffer,
.flush_buffer = rs_flush_buffer,
.ioctl = rs_ioctl,
.throttle = rs_throttle,
.unthrottle = rs_unthrottle,
.set_termios = rs_set_termios,
.stop = rs_stop,
.start = rs_start,
.hangup = rs_hangup,
.set_ldisc = rs_set_ldisc,
};
/* rs_init inits the driver */
static int __init
rs68328_init(void)
{
int flags, i;
struct m68k_serial *info;
serial_driver = alloc_tty_driver(NR_PORTS);
if (!serial_driver)
return -ENOMEM;
show_serial_version();
/* Initialize the tty_driver structure */
/* SPARC: Not all of this is exactly right for us. */
serial_driver->name = "ttyS";
serial_driver->major = TTY_MAJOR;
serial_driver->minor_start = 64;
serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
serial_driver->subtype = SERIAL_TYPE_NORMAL;
serial_driver->init_termios = tty_std_termios;
serial_driver->init_termios.c_cflag =
m68328_console_cbaud | CS8 | CREAD | HUPCL | CLOCAL;
serial_driver->flags = TTY_DRIVER_REAL_RAW;
tty_set_operations(serial_driver, &rs_ops);
if (tty_register_driver(serial_driver)) {
put_tty_driver(serial_driver);
printk(KERN_ERR "Couldn't register serial driver\n");
return -ENOMEM;
}
save_flags(flags); cli();
for(i=0;i<NR_PORTS;i++) {
info = &m68k_soft[i];
info->magic = SERIAL_MAGIC;
info->port = (int) &uart_addr[i];
info->tty = 0;
info->irq = uart_irqs[i];
info->custom_divisor = 16;
info->close_delay = 50;
info->closing_wait = 3000;
info->x_char = 0;
info->event = 0;
info->count = 0;
info->blocked_open = 0;
INIT_WORK(&info->tqueue, do_softint, info);
INIT_WORK(&info->tqueue_hangup, do_serial_hangup, info);
init_waitqueue_head(&info->open_wait);
init_waitqueue_head(&info->close_wait);
info->line = i;
info->is_cons = 1; /* Means shortcuts work */
printk("%s%d at 0x%08x (irq = %d)", serial_driver->name, info->line,
info->port, info->irq);
printk(" is a builtin MC68328 UART\n");
IRQ_ports[info->irq] = info; /* waste of space */
#ifdef CONFIG_M68VZ328
if (i > 0 )
PJSEL &= 0xCF; /* PSW enable second port output */
#endif
if (request_irq(uart_irqs[i],
rs_interrupt,
IRQ_FLG_STD,
"M68328_UART", NULL))
panic("Unable to attach 68328 serial interrupt\n");
#ifdef CONFIG_PM_LEGACY
serial_pm[i] = pm_register(PM_SYS_DEV, PM_SYS_COM, serial_pm_callback);
if (serial_pm[i])
serial_pm[i]->data = info;
#endif
}
restore_flags(flags);
return 0;
}
module_init(rs68328_init);
static void m68328_set_baud(void)
{
unsigned short ustcnt;
int i;
ustcnt = USTCNT;
USTCNT = ustcnt & ~USTCNT_TXEN;
again:
for (i = 0; i < sizeof(baud_table) / sizeof(baud_table[0]); i++)
if (baud_table[i] == m68328_console_baud)
break;
if (i >= sizeof(baud_table) / sizeof(baud_table[0])) {
m68328_console_baud = 9600;
goto again;
}
UBAUD = PUT_FIELD(UBAUD_DIVIDE, hw_baud_table[i].divisor) |
PUT_FIELD(UBAUD_PRESCALER, hw_baud_table[i].prescale);
ustcnt &= ~(USTCNT_PARITYEN | USTCNT_ODD_EVEN | USTCNT_STOP | USTCNT_8_7);
ustcnt |= USTCNT_8_7;
ustcnt |= USTCNT_TXEN;
USTCNT = ustcnt;
m68328_console_initted = 1;
return;
}
int m68328_console_setup(struct console *cp, char *arg)
{
int i, n = CONSOLE_BAUD_RATE;
if (!cp)
return(-1);
if (arg)
n = simple_strtoul(arg,NULL,0);
for (i = 0; i < BAUD_TABLE_SIZE; i++)
if (baud_table[i] == n)
break;
if (i < BAUD_TABLE_SIZE) {
m68328_console_baud = n;
m68328_console_cbaud = 0;
if (i > 15) {
m68328_console_cbaud |= CBAUDEX;
i -= 15;
}
m68328_console_cbaud |= i;
}
m68328_set_baud(); /* make sure baud rate changes */
return(0);
}
static struct tty_driver *m68328_console_device(struct console *c, int *index)
{
*index = c->index;
return serial_driver;
}
void m68328_console_write (struct console *co, const char *str,
unsigned int count)
{
if (!m68328_console_initted)
m68328_set_baud();
while (count--) {
if (*str == '\n')
rs_put_char('\r');
rs_put_char( *str++ );
}
}
static struct console m68328_driver = {
.name = "ttyS",
.write = m68328_console_write,
.device = m68328_console_device,
.setup = m68328_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
};
static int __init m68328_console_init(void)
{
register_console(&m68328_driver);
return 0;
}
console_initcall(m68328_console_init);
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