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linux-next/drivers/serial/ip22zilog.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

1273 lines
32 KiB
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/*
* Driver for Zilog serial chips found on SGI workstations and
* servers. This driver could actually be made more generic.
*
* This is based on the drivers/serial/sunzilog.c code as of 2.6.0-test7 and the
* old drivers/sgi/char/sgiserial.c code which itself is based of the original
* drivers/sbus/char/zs.c code. A lot of code has been simply moved over
* directly from there but much has been rewritten. Credits therefore go out
* to David S. Miller, Eddie C. Dost, Pete Zaitcev, Ted Ts'o and Alex Buell
* for their work there.
*
* Copyright (C) 2002 Ralf Baechle (ralf@linux-mips.org)
* Copyright (C) 2002 David S. Miller (davem@redhat.com)
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/circ_buf.h>
#include <linux/serial.h>
#include <linux/sysrq.h>
#include <linux/console.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/sgialib.h>
#include <asm/sgi/ioc.h>
#include <asm/sgi/hpc3.h>
#include <asm/sgi/ip22.h>
#if defined(CONFIG_SERIAL_IP22_ZILOG_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif
#include <linux/serial_core.h>
#include "ip22zilog.h"
void ip22_do_break(void);
/*
* On IP22 we need to delay after register accesses but we do not need to
* flush writes.
*/
#define ZSDELAY() udelay(5)
#define ZSDELAY_LONG() udelay(20)
#define ZS_WSYNC(channel) do { } while (0)
#define NUM_IP22ZILOG 1
#define NUM_CHANNELS (NUM_IP22ZILOG * 2)
#define ZS_CLOCK 3672000 /* Zilog input clock rate. */
#define ZS_CLOCK_DIVISOR 16 /* Divisor this driver uses. */
/*
* We wrap our port structure around the generic uart_port.
*/
struct uart_ip22zilog_port {
struct uart_port port;
/* IRQ servicing chain. */
struct uart_ip22zilog_port *next;
/* Current values of Zilog write registers. */
unsigned char curregs[NUM_ZSREGS];
unsigned int flags;
#define IP22ZILOG_FLAG_IS_CONS 0x00000004
#define IP22ZILOG_FLAG_IS_KGDB 0x00000008
#define IP22ZILOG_FLAG_MODEM_STATUS 0x00000010
#define IP22ZILOG_FLAG_IS_CHANNEL_A 0x00000020
#define IP22ZILOG_FLAG_REGS_HELD 0x00000040
#define IP22ZILOG_FLAG_TX_STOPPED 0x00000080
#define IP22ZILOG_FLAG_TX_ACTIVE 0x00000100
unsigned int cflag;
/* L1-A keyboard break state. */
int kbd_id;
int l1_down;
unsigned char parity_mask;
unsigned char prev_status;
};
#define ZILOG_CHANNEL_FROM_PORT(PORT) ((struct zilog_channel *)((PORT)->membase))
#define UART_ZILOG(PORT) ((struct uart_ip22zilog_port *)(PORT))
#define IP22ZILOG_GET_CURR_REG(PORT, REGNUM) \
(UART_ZILOG(PORT)->curregs[REGNUM])
#define IP22ZILOG_SET_CURR_REG(PORT, REGNUM, REGVAL) \
((UART_ZILOG(PORT)->curregs[REGNUM]) = (REGVAL))
#define ZS_IS_CONS(UP) ((UP)->flags & IP22ZILOG_FLAG_IS_CONS)
#define ZS_IS_KGDB(UP) ((UP)->flags & IP22ZILOG_FLAG_IS_KGDB)
#define ZS_WANTS_MODEM_STATUS(UP) ((UP)->flags & IP22ZILOG_FLAG_MODEM_STATUS)
#define ZS_IS_CHANNEL_A(UP) ((UP)->flags & IP22ZILOG_FLAG_IS_CHANNEL_A)
#define ZS_REGS_HELD(UP) ((UP)->flags & IP22ZILOG_FLAG_REGS_HELD)
#define ZS_TX_STOPPED(UP) ((UP)->flags & IP22ZILOG_FLAG_TX_STOPPED)
#define ZS_TX_ACTIVE(UP) ((UP)->flags & IP22ZILOG_FLAG_TX_ACTIVE)
/* Reading and writing Zilog8530 registers. The delays are to make this
* driver work on the IP22 which needs a settling delay after each chip
* register access, other machines handle this in hardware via auxiliary
* flip-flops which implement the settle time we do in software.
*
* The port lock must be held and local IRQs must be disabled
* when {read,write}_zsreg is invoked.
*/
static unsigned char read_zsreg(struct zilog_channel *channel,
unsigned char reg)
{
unsigned char retval;
writeb(reg, &channel->control);
ZSDELAY();
retval = readb(&channel->control);
ZSDELAY();
return retval;
}
static void write_zsreg(struct zilog_channel *channel,
unsigned char reg, unsigned char value)
{
writeb(reg, &channel->control);
ZSDELAY();
writeb(value, &channel->control);
ZSDELAY();
}
static void ip22zilog_clear_fifo(struct zilog_channel *channel)
{
int i;
for (i = 0; i < 32; i++) {
unsigned char regval;
regval = readb(&channel->control);
ZSDELAY();
if (regval & Rx_CH_AV)
break;
regval = read_zsreg(channel, R1);
readb(&channel->data);
ZSDELAY();
if (regval & (PAR_ERR | Rx_OVR | CRC_ERR)) {
writeb(ERR_RES, &channel->control);
ZSDELAY();
ZS_WSYNC(channel);
}
}
}
/* This function must only be called when the TX is not busy. The UART
* port lock must be held and local interrupts disabled.
*/
static void __load_zsregs(struct zilog_channel *channel, unsigned char *regs)
{
int i;
/* Let pending transmits finish. */
for (i = 0; i < 1000; i++) {
unsigned char stat = read_zsreg(channel, R1);
if (stat & ALL_SNT)
break;
udelay(100);
}
writeb(ERR_RES, &channel->control);
ZSDELAY();
ZS_WSYNC(channel);
ip22zilog_clear_fifo(channel);
/* Disable all interrupts. */
write_zsreg(channel, R1,
regs[R1] & ~(RxINT_MASK | TxINT_ENAB | EXT_INT_ENAB));
/* Set parity, sync config, stop bits, and clock divisor. */
write_zsreg(channel, R4, regs[R4]);
/* Set misc. TX/RX control bits. */
write_zsreg(channel, R10, regs[R10]);
/* Set TX/RX controls sans the enable bits. */
write_zsreg(channel, R3, regs[R3] & ~RxENAB);
write_zsreg(channel, R5, regs[R5] & ~TxENAB);
/* Synchronous mode config. */
write_zsreg(channel, R6, regs[R6]);
write_zsreg(channel, R7, regs[R7]);
/* Don't mess with the interrupt vector (R2, unused by us) and
* master interrupt control (R9). We make sure this is setup
* properly at probe time then never touch it again.
*/
/* Disable baud generator. */
write_zsreg(channel, R14, regs[R14] & ~BRENAB);
/* Clock mode control. */
write_zsreg(channel, R11, regs[R11]);
/* Lower and upper byte of baud rate generator divisor. */
write_zsreg(channel, R12, regs[R12]);
write_zsreg(channel, R13, regs[R13]);
/* Now rewrite R14, with BRENAB (if set). */
write_zsreg(channel, R14, regs[R14]);
/* External status interrupt control. */
write_zsreg(channel, R15, regs[R15]);
/* Reset external status interrupts. */
write_zsreg(channel, R0, RES_EXT_INT);
write_zsreg(channel, R0, RES_EXT_INT);
/* Rewrite R3/R5, this time without enables masked. */
write_zsreg(channel, R3, regs[R3]);
write_zsreg(channel, R5, regs[R5]);
/* Rewrite R1, this time without IRQ enabled masked. */
write_zsreg(channel, R1, regs[R1]);
}
/* Reprogram the Zilog channel HW registers with the copies found in the
* software state struct. If the transmitter is busy, we defer this update
* until the next TX complete interrupt. Else, we do it right now.
*
* The UART port lock must be held and local interrupts disabled.
*/
static void ip22zilog_maybe_update_regs(struct uart_ip22zilog_port *up,
struct zilog_channel *channel)
{
if (!ZS_REGS_HELD(up)) {
if (ZS_TX_ACTIVE(up)) {
up->flags |= IP22ZILOG_FLAG_REGS_HELD;
} else {
__load_zsregs(channel, up->curregs);
}
}
}
static void ip22zilog_receive_chars(struct uart_ip22zilog_port *up,
struct zilog_channel *channel,
struct pt_regs *regs)
{
struct tty_struct *tty = up->port.info->tty; /* XXX info==NULL? */
while (1) {
unsigned char ch, r1;
if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) {
tty->flip.work.func((void *)tty);
if (tty->flip.count >= TTY_FLIPBUF_SIZE)
return; /* XXX Ignores SysRq when we need it most. Fix. */
}
r1 = read_zsreg(channel, R1);
if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR)) {
writeb(ERR_RES, &channel->control);
ZSDELAY();
ZS_WSYNC(channel);
}
ch = readb(&channel->control);
ZSDELAY();
/* This funny hack depends upon BRK_ABRT not interfering
* with the other bits we care about in R1.
*/
if (ch & BRK_ABRT)
r1 |= BRK_ABRT;
ch = readb(&channel->data);
ZSDELAY();
ch &= up->parity_mask;
if (ZS_IS_CONS(up) && (r1 & BRK_ABRT)) {
/* Wait for BREAK to deassert to avoid potentially
* confusing the PROM.
*/
while (1) {
ch = readb(&channel->control);
ZSDELAY();
if (!(ch & BRK_ABRT))
break;
}
ip22_do_break();
return;
}
/* A real serial line, record the character and status. */
*tty->flip.char_buf_ptr = ch;
*tty->flip.flag_buf_ptr = TTY_NORMAL;
up->port.icount.rx++;
if (r1 & (BRK_ABRT | PAR_ERR | Rx_OVR | CRC_ERR)) {
if (r1 & BRK_ABRT) {
r1 &= ~(PAR_ERR | CRC_ERR);
up->port.icount.brk++;
if (uart_handle_break(&up->port))
goto next_char;
}
else if (r1 & PAR_ERR)
up->port.icount.parity++;
else if (r1 & CRC_ERR)
up->port.icount.frame++;
if (r1 & Rx_OVR)
up->port.icount.overrun++;
r1 &= up->port.read_status_mask;
if (r1 & BRK_ABRT)
*tty->flip.flag_buf_ptr = TTY_BREAK;
else if (r1 & PAR_ERR)
*tty->flip.flag_buf_ptr = TTY_PARITY;
else if (r1 & CRC_ERR)
*tty->flip.flag_buf_ptr = TTY_FRAME;
}
if (uart_handle_sysrq_char(&up->port, ch, regs))
goto next_char;
if (up->port.ignore_status_mask == 0xff ||
(r1 & up->port.ignore_status_mask) == 0) {
tty->flip.flag_buf_ptr++;
tty->flip.char_buf_ptr++;
tty->flip.count++;
}
if ((r1 & Rx_OVR) &&
tty->flip.count < TTY_FLIPBUF_SIZE) {
*tty->flip.flag_buf_ptr = TTY_OVERRUN;
tty->flip.flag_buf_ptr++;
tty->flip.char_buf_ptr++;
tty->flip.count++;
}
next_char:
ch = readb(&channel->control);
ZSDELAY();
if (!(ch & Rx_CH_AV))
break;
}
tty_flip_buffer_push(tty);
}
static void ip22zilog_status_handle(struct uart_ip22zilog_port *up,
struct zilog_channel *channel,
struct pt_regs *regs)
{
unsigned char status;
status = readb(&channel->control);
ZSDELAY();
writeb(RES_EXT_INT, &channel->control);
ZSDELAY();
ZS_WSYNC(channel);
if (ZS_WANTS_MODEM_STATUS(up)) {
if (status & SYNC)
up->port.icount.dsr++;
/* The Zilog just gives us an interrupt when DCD/CTS/etc. change.
* But it does not tell us which bit has changed, we have to keep
* track of this ourselves.
*/
if ((status & DCD) ^ up->prev_status)
uart_handle_dcd_change(&up->port,
(status & DCD));
if ((status & CTS) ^ up->prev_status)
uart_handle_cts_change(&up->port,
(status & CTS));
wake_up_interruptible(&up->port.info->delta_msr_wait);
}
up->prev_status = status;
}
static void ip22zilog_transmit_chars(struct uart_ip22zilog_port *up,
struct zilog_channel *channel)
{
struct circ_buf *xmit;
if (ZS_IS_CONS(up)) {
unsigned char status = readb(&channel->control);
ZSDELAY();
/* TX still busy? Just wait for the next TX done interrupt.
*
* It can occur because of how we do serial console writes. It would
* be nice to transmit console writes just like we normally would for
* a TTY line. (ie. buffered and TX interrupt driven). That is not
* easy because console writes cannot sleep. One solution might be
* to poll on enough port->xmit space becomming free. -DaveM
*/
if (!(status & Tx_BUF_EMP))
return;
}
up->flags &= ~IP22ZILOG_FLAG_TX_ACTIVE;
if (ZS_REGS_HELD(up)) {
__load_zsregs(channel, up->curregs);
up->flags &= ~IP22ZILOG_FLAG_REGS_HELD;
}
if (ZS_TX_STOPPED(up)) {
up->flags &= ~IP22ZILOG_FLAG_TX_STOPPED;
goto ack_tx_int;
}
if (up->port.x_char) {
up->flags |= IP22ZILOG_FLAG_TX_ACTIVE;
writeb(up->port.x_char, &channel->data);
ZSDELAY();
ZS_WSYNC(channel);
up->port.icount.tx++;
up->port.x_char = 0;
return;
}
if (up->port.info == NULL)
goto ack_tx_int;
xmit = &up->port.info->xmit;
if (uart_circ_empty(xmit)) {
uart_write_wakeup(&up->port);
goto ack_tx_int;
}
if (uart_tx_stopped(&up->port))
goto ack_tx_int;
up->flags |= IP22ZILOG_FLAG_TX_ACTIVE;
writeb(xmit->buf[xmit->tail], &channel->data);
ZSDELAY();
ZS_WSYNC(channel);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
up->port.icount.tx++;
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&up->port);
return;
ack_tx_int:
writeb(RES_Tx_P, &channel->control);
ZSDELAY();
ZS_WSYNC(channel);
}
static irqreturn_t ip22zilog_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
struct uart_ip22zilog_port *up = dev_id;
while (up) {
struct zilog_channel *channel
= ZILOG_CHANNEL_FROM_PORT(&up->port);
unsigned char r3;
spin_lock(&up->port.lock);
r3 = read_zsreg(channel, R3);
/* Channel A */
if (r3 & (CHAEXT | CHATxIP | CHARxIP)) {
writeb(RES_H_IUS, &channel->control);
ZSDELAY();
ZS_WSYNC(channel);
if (r3 & CHARxIP)
ip22zilog_receive_chars(up, channel, regs);
if (r3 & CHAEXT)
ip22zilog_status_handle(up, channel, regs);
if (r3 & CHATxIP)
ip22zilog_transmit_chars(up, channel);
}
spin_unlock(&up->port.lock);
/* Channel B */
up = up->next;
channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
spin_lock(&up->port.lock);
if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
writeb(RES_H_IUS, &channel->control);
ZSDELAY();
ZS_WSYNC(channel);
if (r3 & CHBRxIP)
ip22zilog_receive_chars(up, channel, regs);
if (r3 & CHBEXT)
ip22zilog_status_handle(up, channel, regs);
if (r3 & CHBTxIP)
ip22zilog_transmit_chars(up, channel);
}
spin_unlock(&up->port.lock);
up = up->next;
}
return IRQ_HANDLED;
}
/* A convenient way to quickly get R0 status. The caller must _not_ hold the
* port lock, it is acquired here.
*/
static __inline__ unsigned char ip22zilog_read_channel_status(struct uart_port *port)
{
struct zilog_channel *channel;
unsigned char status;
channel = ZILOG_CHANNEL_FROM_PORT(port);
status = readb(&channel->control);
ZSDELAY();
return status;
}
/* The port lock is not held. */
static unsigned int ip22zilog_tx_empty(struct uart_port *port)
{
unsigned long flags;
unsigned char status;
unsigned int ret;
spin_lock_irqsave(&port->lock, flags);
status = ip22zilog_read_channel_status(port);
spin_unlock_irqrestore(&port->lock, flags);
if (status & Tx_BUF_EMP)
ret = TIOCSER_TEMT;
else
ret = 0;
return ret;
}
/* The port lock is held and interrupts are disabled. */
static unsigned int ip22zilog_get_mctrl(struct uart_port *port)
{
unsigned char status;
unsigned int ret;
status = ip22zilog_read_channel_status(port);
ret = 0;
if (status & DCD)
ret |= TIOCM_CAR;
if (status & SYNC)
ret |= TIOCM_DSR;
if (status & CTS)
ret |= TIOCM_CTS;
return ret;
}
/* The port lock is held and interrupts are disabled. */
static void ip22zilog_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
unsigned char set_bits, clear_bits;
set_bits = clear_bits = 0;
if (mctrl & TIOCM_RTS)
set_bits |= RTS;
else
clear_bits |= RTS;
if (mctrl & TIOCM_DTR)
set_bits |= DTR;
else
clear_bits |= DTR;
/* NOTE: Not subject to 'transmitter active' rule. */
up->curregs[R5] |= set_bits;
up->curregs[R5] &= ~clear_bits;
write_zsreg(channel, R5, up->curregs[R5]);
}
/* The port lock is held and interrupts are disabled. */
static void ip22zilog_stop_tx(struct uart_port *port)
{
struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
up->flags |= IP22ZILOG_FLAG_TX_STOPPED;
}
/* The port lock is held and interrupts are disabled. */
static void ip22zilog_start_tx(struct uart_port *port)
{
struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
unsigned char status;
up->flags |= IP22ZILOG_FLAG_TX_ACTIVE;
up->flags &= ~IP22ZILOG_FLAG_TX_STOPPED;
status = readb(&channel->control);
ZSDELAY();
/* TX busy? Just wait for the TX done interrupt. */
if (!(status & Tx_BUF_EMP))
return;
/* Send the first character to jump-start the TX done
* IRQ sending engine.
*/
if (port->x_char) {
writeb(port->x_char, &channel->data);
ZSDELAY();
ZS_WSYNC(channel);
port->icount.tx++;
port->x_char = 0;
} else {
struct circ_buf *xmit = &port->info->xmit;
writeb(xmit->buf[xmit->tail], &channel->data);
ZSDELAY();
ZS_WSYNC(channel);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&up->port);
}
}
/* The port lock is held and interrupts are disabled. */
static void ip22zilog_stop_rx(struct uart_port *port)
{
struct uart_ip22zilog_port *up = UART_ZILOG(port);
struct zilog_channel *channel;
if (ZS_IS_CONS(up))
return;
channel = ZILOG_CHANNEL_FROM_PORT(port);
/* Disable all RX interrupts. */
up->curregs[R1] &= ~RxINT_MASK;
ip22zilog_maybe_update_regs(up, channel);
}
/* The port lock is held. */
static void ip22zilog_enable_ms(struct uart_port *port)
{
struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
unsigned char new_reg;
new_reg = up->curregs[R15] | (DCDIE | SYNCIE | CTSIE);
if (new_reg != up->curregs[R15]) {
up->curregs[R15] = new_reg;
/* NOTE: Not subject to 'transmitter active' rule. */
write_zsreg(channel, R15, up->curregs[R15]);
}
}
/* The port lock is not held. */
static void ip22zilog_break_ctl(struct uart_port *port, int break_state)
{
struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
unsigned char set_bits, clear_bits, new_reg;
unsigned long flags;
set_bits = clear_bits = 0;
if (break_state)
set_bits |= SND_BRK;
else
clear_bits |= SND_BRK;
spin_lock_irqsave(&port->lock, flags);
new_reg = (up->curregs[R5] | set_bits) & ~clear_bits;
if (new_reg != up->curregs[R5]) {
up->curregs[R5] = new_reg;
/* NOTE: Not subject to 'transmitter active' rule. */
write_zsreg(channel, R5, up->curregs[R5]);
}
spin_unlock_irqrestore(&port->lock, flags);
}
static void __ip22zilog_startup(struct uart_ip22zilog_port *up)
{
struct zilog_channel *channel;
channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
up->prev_status = readb(&channel->control);
/* Enable receiver and transmitter. */
up->curregs[R3] |= RxENAB;
up->curregs[R5] |= TxENAB;
up->curregs[R1] |= EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
ip22zilog_maybe_update_regs(up, channel);
}
static int ip22zilog_startup(struct uart_port *port)
{
struct uart_ip22zilog_port *up = UART_ZILOG(port);
unsigned long flags;
if (ZS_IS_CONS(up))
return 0;
spin_lock_irqsave(&port->lock, flags);
__ip22zilog_startup(up);
spin_unlock_irqrestore(&port->lock, flags);
return 0;
}
/*
* The test for ZS_IS_CONS is explained by the following e-mail:
*****
* From: Russell King <rmk@arm.linux.org.uk>
* Date: Sun, 8 Dec 2002 10:18:38 +0000
*
* On Sun, Dec 08, 2002 at 02:43:36AM -0500, Pete Zaitcev wrote:
* > I boot my 2.5 boxes using "console=ttyS0,9600" argument,
* > and I noticed that something is not right with reference
* > counting in this case. It seems that when the console
* > is open by kernel initially, this is not accounted
* > as an open, and uart_startup is not called.
*
* That is correct. We are unable to call uart_startup when the serial
* console is initialised because it may need to allocate memory (as
* request_irq does) and the memory allocators may not have been
* initialised.
*
* 1. initialise the port into a state where it can send characters in the
* console write method.
*
* 2. don't do the actual hardware shutdown in your shutdown() method (but
* do the normal software shutdown - ie, free irqs etc)
*****
*/
static void ip22zilog_shutdown(struct uart_port *port)
{
struct uart_ip22zilog_port *up = UART_ZILOG(port);
struct zilog_channel *channel;
unsigned long flags;
if (ZS_IS_CONS(up))
return;
spin_lock_irqsave(&port->lock, flags);
channel = ZILOG_CHANNEL_FROM_PORT(port);
/* Disable receiver and transmitter. */
up->curregs[R3] &= ~RxENAB;
up->curregs[R5] &= ~TxENAB;
/* Disable all interrupts and BRK assertion. */
up->curregs[R1] &= ~(EXT_INT_ENAB | TxINT_ENAB | RxINT_MASK);
up->curregs[R5] &= ~SND_BRK;
ip22zilog_maybe_update_regs(up, channel);
spin_unlock_irqrestore(&port->lock, flags);
}
/* Shared by TTY driver and serial console setup. The port lock is held
* and local interrupts are disabled.
*/
static void
ip22zilog_convert_to_zs(struct uart_ip22zilog_port *up, unsigned int cflag,
unsigned int iflag, int brg)
{
up->curregs[R10] = NRZ;
up->curregs[R11] = TCBR | RCBR;
/* Program BAUD and clock source. */
up->curregs[R4] &= ~XCLK_MASK;
up->curregs[R4] |= X16CLK;
up->curregs[R12] = brg & 0xff;
up->curregs[R13] = (brg >> 8) & 0xff;
up->curregs[R14] = BRENAB;
/* Character size, stop bits, and parity. */
up->curregs[3] &= ~RxN_MASK;
up->curregs[5] &= ~TxN_MASK;
switch (cflag & CSIZE) {
case CS5:
up->curregs[3] |= Rx5;
up->curregs[5] |= Tx5;
up->parity_mask = 0x1f;
break;
case CS6:
up->curregs[3] |= Rx6;
up->curregs[5] |= Tx6;
up->parity_mask = 0x3f;
break;
case CS7:
up->curregs[3] |= Rx7;
up->curregs[5] |= Tx7;
up->parity_mask = 0x7f;
break;
case CS8:
default:
up->curregs[3] |= Rx8;
up->curregs[5] |= Tx8;
up->parity_mask = 0xff;
break;
};
up->curregs[4] &= ~0x0c;
if (cflag & CSTOPB)
up->curregs[4] |= SB2;
else
up->curregs[4] |= SB1;
if (cflag & PARENB)
up->curregs[4] |= PAR_ENAB;
else
up->curregs[4] &= ~PAR_ENAB;
if (!(cflag & PARODD))
up->curregs[4] |= PAR_EVEN;
else
up->curregs[4] &= ~PAR_EVEN;
up->port.read_status_mask = Rx_OVR;
if (iflag & INPCK)
up->port.read_status_mask |= CRC_ERR | PAR_ERR;
if (iflag & (BRKINT | PARMRK))
up->port.read_status_mask |= BRK_ABRT;
up->port.ignore_status_mask = 0;
if (iflag & IGNPAR)
up->port.ignore_status_mask |= CRC_ERR | PAR_ERR;
if (iflag & IGNBRK) {
up->port.ignore_status_mask |= BRK_ABRT;
if (iflag & IGNPAR)
up->port.ignore_status_mask |= Rx_OVR;
}
if ((cflag & CREAD) == 0)
up->port.ignore_status_mask = 0xff;
}
/* The port lock is not held. */
static void
ip22zilog_set_termios(struct uart_port *port, struct termios *termios,
struct termios *old)
{
struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
unsigned long flags;
int baud, brg;
baud = uart_get_baud_rate(port, termios, old, 1200, 76800);
spin_lock_irqsave(&up->port.lock, flags);
brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
ip22zilog_convert_to_zs(up, termios->c_cflag, termios->c_iflag, brg);
if (UART_ENABLE_MS(&up->port, termios->c_cflag))
up->flags |= IP22ZILOG_FLAG_MODEM_STATUS;
else
up->flags &= ~IP22ZILOG_FLAG_MODEM_STATUS;
up->cflag = termios->c_cflag;
ip22zilog_maybe_update_regs(up, ZILOG_CHANNEL_FROM_PORT(port));
spin_unlock_irqrestore(&up->port.lock, flags);
}
static const char *ip22zilog_type(struct uart_port *port)
{
return "IP22-Zilog";
}
/* We do not request/release mappings of the registers here, this
* happens at early serial probe time.
*/
static void ip22zilog_release_port(struct uart_port *port)
{
}
static int ip22zilog_request_port(struct uart_port *port)
{
return 0;
}
/* These do not need to do anything interesting either. */
static void ip22zilog_config_port(struct uart_port *port, int flags)
{
}
/* We do not support letting the user mess with the divisor, IRQ, etc. */
static int ip22zilog_verify_port(struct uart_port *port, struct serial_struct *ser)
{
return -EINVAL;
}
static struct uart_ops ip22zilog_pops = {
.tx_empty = ip22zilog_tx_empty,
.set_mctrl = ip22zilog_set_mctrl,
.get_mctrl = ip22zilog_get_mctrl,
.stop_tx = ip22zilog_stop_tx,
.start_tx = ip22zilog_start_tx,
.stop_rx = ip22zilog_stop_rx,
.enable_ms = ip22zilog_enable_ms,
.break_ctl = ip22zilog_break_ctl,
.startup = ip22zilog_startup,
.shutdown = ip22zilog_shutdown,
.set_termios = ip22zilog_set_termios,
.type = ip22zilog_type,
.release_port = ip22zilog_release_port,
.request_port = ip22zilog_request_port,
.config_port = ip22zilog_config_port,
.verify_port = ip22zilog_verify_port,
};
static struct uart_ip22zilog_port *ip22zilog_port_table;
static struct zilog_layout **ip22zilog_chip_regs;
static struct uart_ip22zilog_port *ip22zilog_irq_chain;
static int zilog_irq = -1;
static void * __init alloc_one_table(unsigned long size)
{
void *ret;
ret = kmalloc(size, GFP_KERNEL);
if (ret != NULL)
memset(ret, 0, size);
return ret;
}
static void __init ip22zilog_alloc_tables(void)
{
ip22zilog_port_table = (struct uart_ip22zilog_port *)
alloc_one_table(NUM_CHANNELS * sizeof(struct uart_ip22zilog_port));
ip22zilog_chip_regs = (struct zilog_layout **)
alloc_one_table(NUM_IP22ZILOG * sizeof(struct zilog_layout *));
if (ip22zilog_port_table == NULL || ip22zilog_chip_regs == NULL) {
panic("IP22-Zilog: Cannot allocate IP22-Zilog tables.");
}
}
/* Get the address of the registers for IP22-Zilog instance CHIP. */
static struct zilog_layout * __init get_zs(int chip)
{
unsigned long base;
if (chip < 0 || chip >= NUM_IP22ZILOG) {
panic("IP22-Zilog: Illegal chip number %d in get_zs.", chip);
}
/* Not probe-able, hard code it. */
base = (unsigned long) &sgioc->uart;
zilog_irq = SGI_SERIAL_IRQ;
request_mem_region(base, 8, "IP22-Zilog");
return (struct zilog_layout *) base;
}
#define ZS_PUT_CHAR_MAX_DELAY 2000 /* 10 ms */
#ifdef CONFIG_SERIAL_IP22_ZILOG_CONSOLE
static void ip22zilog_put_char(struct zilog_channel *channel, unsigned char ch)
{
int loops = ZS_PUT_CHAR_MAX_DELAY;
/* This is a timed polling loop so do not switch the explicit
* udelay with ZSDELAY as that is a NOP on some platforms. -DaveM
*/
do {
unsigned char val = readb(&channel->control);
if (val & Tx_BUF_EMP) {
ZSDELAY();
break;
}
udelay(5);
} while (--loops);
writeb(ch, &channel->data);
ZSDELAY();
ZS_WSYNC(channel);
}
static void
ip22zilog_console_write(struct console *con, const char *s, unsigned int count)
{
struct uart_ip22zilog_port *up = &ip22zilog_port_table[con->index];
struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
unsigned long flags;
int i;
spin_lock_irqsave(&up->port.lock, flags);
for (i = 0; i < count; i++, s++) {
ip22zilog_put_char(channel, *s);
if (*s == 10)
ip22zilog_put_char(channel, 13);
}
udelay(2);
spin_unlock_irqrestore(&up->port.lock, flags);
}
void
ip22serial_console_termios(struct console *con, char *options)
{
int baud = 9600, bits = 8, cflag;
int parity = 'n';
int flow = 'n';
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
cflag = CREAD | HUPCL | CLOCAL;
switch (baud) {
case 150: cflag |= B150; break;
case 300: cflag |= B300; break;
case 600: cflag |= B600; break;
case 1200: cflag |= B1200; break;
case 2400: cflag |= B2400; break;
case 4800: cflag |= B4800; break;
case 9600: cflag |= B9600; break;
case 19200: cflag |= B19200; break;
case 38400: cflag |= B38400; break;
default: baud = 9600; cflag |= B9600; break;
}
con->cflag = cflag | CS8; /* 8N1 */
}
static int __init ip22zilog_console_setup(struct console *con, char *options)
{
struct uart_ip22zilog_port *up = &ip22zilog_port_table[con->index];
unsigned long flags;
int baud, brg;
printk("Console: ttyS%d (IP22-Zilog)\n", con->index);
/* Get firmware console settings. */
ip22serial_console_termios(con, options);
/* Firmware console speed is limited to 150-->38400 baud so
* this hackish cflag thing is OK.
*/
switch (con->cflag & CBAUD) {
case B150: baud = 150; break;
case B300: baud = 300; break;
case B600: baud = 600; break;
case B1200: baud = 1200; break;
case B2400: baud = 2400; break;
case B4800: baud = 4800; break;
default: case B9600: baud = 9600; break;
case B19200: baud = 19200; break;
case B38400: baud = 38400; break;
};
brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
spin_lock_irqsave(&up->port.lock, flags);
up->curregs[R15] = BRKIE;
ip22zilog_convert_to_zs(up, con->cflag, 0, brg);
__ip22zilog_startup(up);
spin_unlock_irqrestore(&up->port.lock, flags);
return 0;
}
static struct uart_driver ip22zilog_reg;
static struct console ip22zilog_console = {
.name = "ttyS",
.write = ip22zilog_console_write,
.device = uart_console_device,
.setup = ip22zilog_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &ip22zilog_reg,
};
#endif /* CONFIG_SERIAL_IP22_ZILOG_CONSOLE */
static struct uart_driver ip22zilog_reg = {
.owner = THIS_MODULE,
.driver_name = "serial",
.devfs_name = "tts/",
.dev_name = "ttyS",
.major = TTY_MAJOR,
.minor = 64,
.nr = NUM_CHANNELS,
#ifdef CONFIG_SERIAL_IP22_ZILOG_CONSOLE
.cons = &ip22zilog_console,
#endif
};
static void __init ip22zilog_prepare(void)
{
struct uart_ip22zilog_port *up;
struct zilog_layout *rp;
int channel, chip;
/*
* Temporary fix.
*/
for (channel = 0; channel < NUM_CHANNELS; channel++)
spin_lock_init(&ip22zilog_port_table[channel].port.lock);
ip22zilog_irq_chain = &ip22zilog_port_table[NUM_CHANNELS - 1];
up = &ip22zilog_port_table[0];
for (channel = NUM_CHANNELS - 1 ; channel > 0; channel--)
up[channel].next = &up[channel - 1];
up[channel].next = NULL;
for (chip = 0; chip < NUM_IP22ZILOG; chip++) {
if (!ip22zilog_chip_regs[chip]) {
ip22zilog_chip_regs[chip] = rp = get_zs(chip);
up[(chip * 2) + 0].port.membase = (char *) &rp->channelB;
up[(chip * 2) + 1].port.membase = (char *) &rp->channelA;
/* In theory mapbase is the physical address ... */
up[(chip * 2) + 0].port.mapbase =
(unsigned long) ioremap((unsigned long) &rp->channelB, 8);
up[(chip * 2) + 1].port.mapbase =
(unsigned long) ioremap((unsigned long) &rp->channelA, 8);
}
/* Channel A */
up[(chip * 2) + 0].port.iotype = UPIO_MEM;
up[(chip * 2) + 0].port.irq = zilog_irq;
up[(chip * 2) + 0].port.uartclk = ZS_CLOCK;
up[(chip * 2) + 0].port.fifosize = 1;
up[(chip * 2) + 0].port.ops = &ip22zilog_pops;
up[(chip * 2) + 0].port.type = PORT_IP22ZILOG;
up[(chip * 2) + 0].port.flags = 0;
up[(chip * 2) + 0].port.line = (chip * 2) + 0;
up[(chip * 2) + 0].flags = 0;
/* Channel B */
up[(chip * 2) + 1].port.iotype = UPIO_MEM;
up[(chip * 2) + 1].port.irq = zilog_irq;
up[(chip * 2) + 1].port.uartclk = ZS_CLOCK;
up[(chip * 2) + 1].port.fifosize = 1;
up[(chip * 2) + 1].port.ops = &ip22zilog_pops;
up[(chip * 2) + 1].port.type = PORT_IP22ZILOG;
up[(chip * 2) + 1].port.flags |= IP22ZILOG_FLAG_IS_CHANNEL_A;
up[(chip * 2) + 1].port.line = (chip * 2) + 1;
up[(chip * 2) + 1].flags = 0;
}
}
static void __init ip22zilog_init_hw(void)
{
int i;
for (i = 0; i < NUM_CHANNELS; i++) {
struct uart_ip22zilog_port *up = &ip22zilog_port_table[i];
struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
unsigned long flags;
int baud, brg;
spin_lock_irqsave(&up->port.lock, flags);
if (ZS_IS_CHANNEL_A(up)) {
write_zsreg(channel, R9, FHWRES);
ZSDELAY_LONG();
(void) read_zsreg(channel, R0);
}
/* Normal serial TTY. */
up->parity_mask = 0xff;
up->curregs[R1] = EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
up->curregs[R4] = PAR_EVEN | X16CLK | SB1;
up->curregs[R3] = RxENAB | Rx8;
up->curregs[R5] = TxENAB | Tx8;
up->curregs[R9] = NV | MIE;
up->curregs[R10] = NRZ;
up->curregs[R11] = TCBR | RCBR;
baud = 9600;
brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
up->curregs[R12] = (brg & 0xff);
up->curregs[R13] = (brg >> 8) & 0xff;
up->curregs[R14] = BRENAB;
__load_zsregs(channel, up->curregs);
/* set master interrupt enable */
write_zsreg(channel, R9, up->curregs[R9]);
spin_unlock_irqrestore(&up->port.lock, flags);
}
}
static int __init ip22zilog_ports_init(void)
{
int ret;
printk(KERN_INFO "Serial: IP22 Zilog driver (%d chips).\n", NUM_IP22ZILOG);
ip22zilog_prepare();
if (request_irq(zilog_irq, ip22zilog_interrupt, 0,
"IP22-Zilog", ip22zilog_irq_chain)) {
panic("IP22-Zilog: Unable to register zs interrupt handler.\n");
}
ip22zilog_init_hw();
ret = uart_register_driver(&ip22zilog_reg);
if (ret == 0) {
int i;
for (i = 0; i < NUM_CHANNELS; i++) {
struct uart_ip22zilog_port *up = &ip22zilog_port_table[i];
uart_add_one_port(&ip22zilog_reg, &up->port);
}
}
return ret;
}
static int __init ip22zilog_init(void)
{
/* IP22 Zilog setup is hard coded, no probing to do. */
ip22zilog_alloc_tables();
ip22zilog_ports_init();
return 0;
}
static void __exit ip22zilog_exit(void)
{
int i;
for (i = 0; i < NUM_CHANNELS; i++) {
struct uart_ip22zilog_port *up = &ip22zilog_port_table[i];
uart_remove_one_port(&ip22zilog_reg, &up->port);
}
uart_unregister_driver(&ip22zilog_reg);
}
module_init(ip22zilog_init);
module_exit(ip22zilog_exit);
/* David wrote it but I'm to blame for the bugs ... */
MODULE_AUTHOR("Ralf Baechle <ralf@linux-mips.org>");
MODULE_DESCRIPTION("SGI Zilog serial port driver");
MODULE_LICENSE("GPL");
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