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pmac_zilog.c
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/*
* linux/drivers/serial/pmac_zilog.c
*
* Driver for PowerMac Z85c30 based ESCC cell found in the
* "macio" ASICs of various PowerMac models
*
* Copyright (C) 2003 Ben. Herrenschmidt ([email protected])
*
* Derived from drivers/macintosh/macserial.c by Paul Mackerras
* and drivers/serial/sunzilog.c by David S. Miller
*
* Hrm... actually, I ripped most of sunzilog (Thanks David !) and
* adapted special tweaks needed for us. I don't think it's worth
* merging back those though. The DMA code still has to get in
* and once done, I expect that driver to remain fairly stable in
* the long term, unless we change the driver model again...
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* 2004-08-06 Harald Welte <[email protected]>
* - Enable BREAK interrupt
* - Add support for sysreq
*
* TODO: - Add DMA support
* - Defer port shutdown to a few seconds after close
* - maybe put something right into uap->clk_divisor
*/
#undef DEBUG
#undef DEBUG_HARD
#undef USE_CTRL_O_SYSRQ
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/slab.h>
#include <linux/adb.h>
#include <linux/pmu.h>
#include <linux/bitops.h>
#include <linux/sysrq.h>
#include <linux/mutex.h>
#include <asm/sections.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/pmac_feature.h>
#include <asm/dbdma.h>
#include <asm/macio.h>
#if defined (CONFIG_SERIAL_PMACZILOG_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif
#include <linux/serial.h>
#include <linux/serial_core.h>
#include "pmac_zilog.h"
/* Not yet implemented */
#undef HAS_DBDMA
static char version[] __initdata = "pmac_zilog: 0.6 (Benjamin Herrenschmidt <[email protected]>)";
MODULE_AUTHOR("Benjamin Herrenschmidt <[email protected]>");
MODULE_DESCRIPTION("Driver for the PowerMac serial ports.");
MODULE_LICENSE("GPL");
#define PWRDBG(fmt, arg...) printk(KERN_DEBUG fmt , ## arg)
#ifdef CONFIG_SERIAL_PMACZILOG_TTYS
#define PMACZILOG_MAJOR TTY_MAJOR
#define PMACZILOG_MINOR 64
#define PMACZILOG_NAME "ttyS"
#else
#define PMACZILOG_MAJOR 204
#define PMACZILOG_MINOR 192
#define PMACZILOG_NAME "ttyPZ"
#endif
/*
* For the sake of early serial console, we can do a pre-probe
* (optional) of the ports at rather early boot time.
*/
static struct uart_pmac_port pmz_ports[MAX_ZS_PORTS];
static int pmz_ports_count;
static DEFINE_MUTEX(pmz_irq_mutex);
static struct uart_driver pmz_uart_reg = {
.owner = THIS_MODULE,
.driver_name = PMACZILOG_NAME,
.dev_name = PMACZILOG_NAME,
.major = PMACZILOG_MAJOR,
.minor = PMACZILOG_MINOR,
};
/*
* Load all registers to reprogram the port
* 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 pmz_load_zsregs(struct uart_pmac_port *uap, u8 *regs)
{
int i;
if (ZS_IS_ASLEEP(uap))
return;
/* Let pending transmits finish. */
for (i = 0; i < 1000; i++) {
unsigned char stat = read_zsreg(uap, R1);
if (stat & ALL_SNT)
break;
udelay(100);
}
ZS_CLEARERR(uap);
zssync(uap);
ZS_CLEARFIFO(uap);
zssync(uap);
ZS_CLEARERR(uap);
/* Disable all interrupts. */
write_zsreg(uap, R1,
regs[R1] & ~(RxINT_MASK | TxINT_ENAB | EXT_INT_ENAB));
/* Set parity, sync config, stop bits, and clock divisor. */
write_zsreg(uap, R4, regs[R4]);
/* Set misc. TX/RX control bits. */
write_zsreg(uap, R10, regs[R10]);
/* Set TX/RX controls sans the enable bits. */
write_zsreg(uap, R3, regs[R3] & ~RxENABLE);
write_zsreg(uap, R5, regs[R5] & ~TxENABLE);
/* now set R7 "prime" on ESCC */
write_zsreg(uap, R15, regs[R15] | EN85C30);
write_zsreg(uap, R7, regs[R7P]);
/* make sure we use R7 "non-prime" on ESCC */
write_zsreg(uap, R15, regs[R15] & ~EN85C30);
/* Synchronous mode config. */
write_zsreg(uap, R6, regs[R6]);
write_zsreg(uap, R7, regs[R7]);
/* Disable baud generator. */
write_zsreg(uap, R14, regs[R14] & ~BRENAB);
/* Clock mode control. */
write_zsreg(uap, R11, regs[R11]);
/* Lower and upper byte of baud rate generator divisor. */
write_zsreg(uap, R12, regs[R12]);
write_zsreg(uap, R13, regs[R13]);
/* Now rewrite R14, with BRENAB (if set). */
write_zsreg(uap, R14, regs[R14]);
/* Reset external status interrupts. */
write_zsreg(uap, R0, RES_EXT_INT);
write_zsreg(uap, R0, RES_EXT_INT);
/* Rewrite R3/R5, this time without enables masked. */
write_zsreg(uap, R3, regs[R3]);
write_zsreg(uap, R5, regs[R5]);
/* Rewrite R1, this time without IRQ enabled masked. */
write_zsreg(uap, R1, regs[R1]);
/* Enable interrupts */
write_zsreg(uap, R9, regs[R9]);
}
/*
* We do like sunzilog to avoid disrupting pending Tx
* 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 pmz_maybe_update_regs(struct uart_pmac_port *uap)
{
if (!ZS_REGS_HELD(uap)) {
if (ZS_TX_ACTIVE(uap)) {
uap->flags |= PMACZILOG_FLAG_REGS_HELD;
} else {
pmz_debug("pmz: maybe_update_regs: updating\n");
pmz_load_zsregs(uap, uap->curregs);
}
}
}
static struct tty_struct *pmz_receive_chars(struct uart_pmac_port *uap)
{
struct tty_struct *tty = NULL;
unsigned char ch, r1, drop, error, flag;
int loops = 0;
/* The interrupt can be enabled when the port isn't open, typically
* that happens when using one port is open and the other closed (stale
* interrupt) or when one port is used as a console.
*/
if (!ZS_IS_OPEN(uap)) {
pmz_debug("pmz: draining input\n");
/* Port is closed, drain input data */
for (;;) {
if ((++loops) > 1000)
goto flood;
(void)read_zsreg(uap, R1);
write_zsreg(uap, R0, ERR_RES);
(void)read_zsdata(uap);
ch = read_zsreg(uap, R0);
if (!(ch & Rx_CH_AV))
break;
}
return NULL;
}
/* Sanity check, make sure the old bug is no longer happening */
if (uap->port.info == NULL || uap->port.info->tty == NULL) {
WARN_ON(1);
(void)read_zsdata(uap);
return NULL;
}
tty = uap->port.info->tty;
while (1) {
error = 0;
drop = 0;
r1 = read_zsreg(uap, R1);
ch = read_zsdata(uap);
if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR)) {
write_zsreg(uap, R0, ERR_RES);
zssync(uap);
}
ch &= uap->parity_mask;
if (ch == 0 && uap->flags & PMACZILOG_FLAG_BREAK) {
uap->flags &= ~PMACZILOG_FLAG_BREAK;
}
#if defined(CONFIG_MAGIC_SYSRQ) && defined(CONFIG_SERIAL_CORE_CONSOLE)
#ifdef USE_CTRL_O_SYSRQ
/* Handle the SysRq ^O Hack */
if (ch == '\x0f') {
uap->port.sysrq = jiffies + HZ*5;
goto next_char;
}
#endif /* USE_CTRL_O_SYSRQ */
if (uap->port.sysrq) {
int swallow;
spin_unlock(&uap->port.lock);
swallow = uart_handle_sysrq_char(&uap->port, ch);
spin_lock(&uap->port.lock);
if (swallow)
goto next_char;
}
#endif /* CONFIG_MAGIC_SYSRQ && CONFIG_SERIAL_CORE_CONSOLE */
/* A real serial line, record the character and status. */
if (drop)
goto next_char;
flag = TTY_NORMAL;
uap->port.icount.rx++;
if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR | BRK_ABRT)) {
error = 1;
if (r1 & BRK_ABRT) {
pmz_debug("pmz: got break !\n");
r1 &= ~(PAR_ERR | CRC_ERR);
uap->port.icount.brk++;
if (uart_handle_break(&uap->port))
goto next_char;
}
else if (r1 & PAR_ERR)
uap->port.icount.parity++;
else if (r1 & CRC_ERR)
uap->port.icount.frame++;
if (r1 & Rx_OVR)
uap->port.icount.overrun++;
r1 &= uap->port.read_status_mask;
if (r1 & BRK_ABRT)
flag = TTY_BREAK;
else if (r1 & PAR_ERR)
flag = TTY_PARITY;
else if (r1 & CRC_ERR)
flag = TTY_FRAME;
}
if (uap->port.ignore_status_mask == 0xff ||
(r1 & uap->port.ignore_status_mask) == 0) {
tty_insert_flip_char(tty, ch, flag);
}
if (r1 & Rx_OVR)
tty_insert_flip_char(tty, 0, TTY_OVERRUN);
next_char:
/* We can get stuck in an infinite loop getting char 0 when the
* line is in a wrong HW state, we break that here.
* When that happens, I disable the receive side of the driver.
* Note that what I've been experiencing is a real irq loop where
* I'm getting flooded regardless of the actual port speed.
* Something stange is going on with the HW
*/
if ((++loops) > 1000)
goto flood;
ch = read_zsreg(uap, R0);
if (!(ch & Rx_CH_AV))
break;
}
return tty;
flood:
uap->curregs[R1] &= ~(EXT_INT_ENAB | TxINT_ENAB | RxINT_MASK);
write_zsreg(uap, R1, uap->curregs[R1]);
zssync(uap);
dev_err(&uap->dev->ofdev.dev, "pmz: rx irq flood !\n");
return tty;
}
static void pmz_status_handle(struct uart_pmac_port *uap)
{
unsigned char status;
status = read_zsreg(uap, R0);
write_zsreg(uap, R0, RES_EXT_INT);
zssync(uap);
if (ZS_IS_OPEN(uap) && ZS_WANTS_MODEM_STATUS(uap)) {
if (status & SYNC_HUNT)
uap->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.
* The CTS input is inverted for some reason. -- paulus
*/
if ((status ^ uap->prev_status) & DCD)
uart_handle_dcd_change(&uap->port,
(status & DCD));
if ((status ^ uap->prev_status) & CTS)
uart_handle_cts_change(&uap->port,
!(status & CTS));
wake_up_interruptible(&uap->port.info->delta_msr_wait);
}
if (status & BRK_ABRT)
uap->flags |= PMACZILOG_FLAG_BREAK;
uap->prev_status = status;
}
static void pmz_transmit_chars(struct uart_pmac_port *uap)
{
struct circ_buf *xmit;
if (ZS_IS_ASLEEP(uap))
return;
if (ZS_IS_CONS(uap)) {
unsigned char status = read_zsreg(uap, R0);
/* 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;
}
uap->flags &= ~PMACZILOG_FLAG_TX_ACTIVE;
if (ZS_REGS_HELD(uap)) {
pmz_load_zsregs(uap, uap->curregs);
uap->flags &= ~PMACZILOG_FLAG_REGS_HELD;
}
if (ZS_TX_STOPPED(uap)) {
uap->flags &= ~PMACZILOG_FLAG_TX_STOPPED;
goto ack_tx_int;
}
if (uap->port.x_char) {
uap->flags |= PMACZILOG_FLAG_TX_ACTIVE;
write_zsdata(uap, uap->port.x_char);
zssync(uap);
uap->port.icount.tx++;
uap->port.x_char = 0;
return;
}
if (uap->port.info == NULL)
goto ack_tx_int;
xmit = &uap->port.info->xmit;
if (uart_circ_empty(xmit)) {
uart_write_wakeup(&uap->port);
goto ack_tx_int;
}
if (uart_tx_stopped(&uap->port))
goto ack_tx_int;
uap->flags |= PMACZILOG_FLAG_TX_ACTIVE;
write_zsdata(uap, xmit->buf[xmit->tail]);
zssync(uap);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
uap->port.icount.tx++;
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&uap->port);
return;
ack_tx_int:
write_zsreg(uap, R0, RES_Tx_P);
zssync(uap);
}
/* Hrm... we register that twice, fixme later.... */
static irqreturn_t pmz_interrupt(int irq, void *dev_id)
{
struct uart_pmac_port *uap = dev_id;
struct uart_pmac_port *uap_a;
struct uart_pmac_port *uap_b;
int rc = IRQ_NONE;
struct tty_struct *tty;
u8 r3;
uap_a = pmz_get_port_A(uap);
uap_b = uap_a->mate;
spin_lock(&uap_a->port.lock);
r3 = read_zsreg(uap_a, R3);
#ifdef DEBUG_HARD
pmz_debug("irq, r3: %x\n", r3);
#endif
/* Channel A */
tty = NULL;
if (r3 & (CHAEXT | CHATxIP | CHARxIP)) {
write_zsreg(uap_a, R0, RES_H_IUS);
zssync(uap_a);
if (r3 & CHAEXT)
pmz_status_handle(uap_a);
if (r3 & CHARxIP)
tty = pmz_receive_chars(uap_a);
if (r3 & CHATxIP)
pmz_transmit_chars(uap_a);
rc = IRQ_HANDLED;
}
spin_unlock(&uap_a->port.lock);
if (tty != NULL)
tty_flip_buffer_push(tty);
if (uap_b->node == NULL)
goto out;
spin_lock(&uap_b->port.lock);
tty = NULL;
if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
write_zsreg(uap_b, R0, RES_H_IUS);
zssync(uap_b);
if (r3 & CHBEXT)
pmz_status_handle(uap_b);
if (r3 & CHBRxIP)
tty = pmz_receive_chars(uap_b);
if (r3 & CHBTxIP)
pmz_transmit_chars(uap_b);
rc = IRQ_HANDLED;
}
spin_unlock(&uap_b->port.lock);
if (tty != NULL)
tty_flip_buffer_push(tty);
out:
#ifdef DEBUG_HARD
pmz_debug("irq done.\n");
#endif
return rc;
}
/*
* Peek the status register, lock not held by caller
*/
static inline u8 pmz_peek_status(struct uart_pmac_port *uap)
{
unsigned long flags;
u8 status;
spin_lock_irqsave(&uap->port.lock, flags);
status = read_zsreg(uap, R0);
spin_unlock_irqrestore(&uap->port.lock, flags);
return status;
}
/*
* Check if transmitter is empty
* The port lock is not held.
*/
static unsigned int pmz_tx_empty(struct uart_port *port)
{
struct uart_pmac_port *uap = to_pmz(port);
unsigned char status;
if (ZS_IS_ASLEEP(uap) || uap->node == NULL)
return TIOCSER_TEMT;
status = pmz_peek_status(to_pmz(port));
if (status & Tx_BUF_EMP)
return TIOCSER_TEMT;
return 0;
}
/*
* Set Modem Control (RTS & DTR) bits
* The port lock is held and interrupts are disabled.
* Note: Shall we really filter out RTS on external ports or
* should that be dealt at higher level only ?
*/
static void pmz_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
struct uart_pmac_port *uap = to_pmz(port);
unsigned char set_bits, clear_bits;
/* Do nothing for irda for now... */
if (ZS_IS_IRDA(uap))
return;
/* We get called during boot with a port not up yet */
if (ZS_IS_ASLEEP(uap) ||
!(ZS_IS_OPEN(uap) || ZS_IS_CONS(uap)))
return;
set_bits = clear_bits = 0;
if (ZS_IS_INTMODEM(uap)) {
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. */
uap->curregs[R5] |= set_bits;
uap->curregs[R5] &= ~clear_bits;
if (ZS_IS_ASLEEP(uap))
return;
write_zsreg(uap, R5, uap->curregs[R5]);
pmz_debug("pmz_set_mctrl: set bits: %x, clear bits: %x -> %x\n",
set_bits, clear_bits, uap->curregs[R5]);
zssync(uap);
}
/*
* Get Modem Control bits (only the input ones, the core will
* or that with a cached value of the control ones)
* The port lock is held and interrupts are disabled.
*/
static unsigned int pmz_get_mctrl(struct uart_port *port)
{
struct uart_pmac_port *uap = to_pmz(port);
unsigned char status;
unsigned int ret;
if (ZS_IS_ASLEEP(uap) || uap->node == NULL)
return 0;
status = read_zsreg(uap, R0);
ret = 0;
if (status & DCD)
ret |= TIOCM_CAR;
if (status & SYNC_HUNT)
ret |= TIOCM_DSR;
if (!(status & CTS))
ret |= TIOCM_CTS;
return ret;
}
/*
* Stop TX side. Dealt like sunzilog at next Tx interrupt,
* though for DMA, we will have to do a bit more.
* The port lock is held and interrupts are disabled.
*/
static void pmz_stop_tx(struct uart_port *port)
{
to_pmz(port)->flags |= PMACZILOG_FLAG_TX_STOPPED;
}
/*
* Kick the Tx side.
* The port lock is held and interrupts are disabled.
*/
static void pmz_start_tx(struct uart_port *port)
{
struct uart_pmac_port *uap = to_pmz(port);
unsigned char status;
pmz_debug("pmz: start_tx()\n");
uap->flags |= PMACZILOG_FLAG_TX_ACTIVE;
uap->flags &= ~PMACZILOG_FLAG_TX_STOPPED;
if (ZS_IS_ASLEEP(uap) || uap->node == NULL)
return;
status = read_zsreg(uap, R0);
/* 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) {
write_zsdata(uap, port->x_char);
zssync(uap);
port->icount.tx++;
port->x_char = 0;
} else {
struct circ_buf *xmit = &port->info->xmit;
write_zsdata(uap, xmit->buf[xmit->tail]);
zssync(uap);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&uap->port);
}
pmz_debug("pmz: start_tx() done.\n");
}
/*
* Stop Rx side, basically disable emitting of
* Rx interrupts on the port. We don't disable the rx
* side of the chip proper though
* The port lock is held.
*/
static void pmz_stop_rx(struct uart_port *port)
{
struct uart_pmac_port *uap = to_pmz(port);
if (ZS_IS_ASLEEP(uap) || uap->node == NULL)
return;
pmz_debug("pmz: stop_rx()()\n");
/* Disable all RX interrupts. */
uap->curregs[R1] &= ~RxINT_MASK;
pmz_maybe_update_regs(uap);
pmz_debug("pmz: stop_rx() done.\n");
}
/*
* Enable modem status change interrupts
* The port lock is held.
*/
static void pmz_enable_ms(struct uart_port *port)
{
struct uart_pmac_port *uap = to_pmz(port);
unsigned char new_reg;
if (ZS_IS_IRDA(uap) || uap->node == NULL)
return;
new_reg = uap->curregs[R15] | (DCDIE | SYNCIE | CTSIE);
if (new_reg != uap->curregs[R15]) {
uap->curregs[R15] = new_reg;
if (ZS_IS_ASLEEP(uap))
return;
/* NOTE: Not subject to 'transmitter active' rule. */
write_zsreg(uap, R15, uap->curregs[R15]);
}
}
/*
* Control break state emission
* The port lock is not held.
*/
static void pmz_break_ctl(struct uart_port *port, int break_state)
{
struct uart_pmac_port *uap = to_pmz(port);
unsigned char set_bits, clear_bits, new_reg;
unsigned long flags;
if (uap->node == NULL)
return;
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 = (uap->curregs[R5] | set_bits) & ~clear_bits;
if (new_reg != uap->curregs[R5]) {
uap->curregs[R5] = new_reg;
/* NOTE: Not subject to 'transmitter active' rule. */
if (ZS_IS_ASLEEP(uap))
return;
write_zsreg(uap, R5, uap->curregs[R5]);
}
spin_unlock_irqrestore(&port->lock, flags);
}
/*
* Turn power on or off to the SCC and associated stuff
* (port drivers, modem, IR port, etc.)
* Returns the number of milliseconds we should wait before
* trying to use the port.
*/
static int pmz_set_scc_power(struct uart_pmac_port *uap, int state)
{
int delay = 0;
int rc;
if (state) {
rc = pmac_call_feature(
PMAC_FTR_SCC_ENABLE, uap->node, uap->port_type, 1);
pmz_debug("port power on result: %d\n", rc);
if (ZS_IS_INTMODEM(uap)) {
rc = pmac_call_feature(
PMAC_FTR_MODEM_ENABLE, uap->node, 0, 1);
delay = 2500; /* wait for 2.5s before using */
pmz_debug("modem power result: %d\n", rc);
}
} else {
/* TODO: Make that depend on a timer, don't power down
* immediately
*/
if (ZS_IS_INTMODEM(uap)) {
rc = pmac_call_feature(
PMAC_FTR_MODEM_ENABLE, uap->node, 0, 0);
pmz_debug("port power off result: %d\n", rc);
}
pmac_call_feature(PMAC_FTR_SCC_ENABLE, uap->node, uap->port_type, 0);
}
return delay;
}
/*
* FixZeroBug....Works around a bug in the SCC receving channel.
* Inspired from Darwin code, 15 Sept. 2000 -DanM
*
* The following sequence prevents a problem that is seen with O'Hare ASICs
* (most versions -- also with some Heathrow and Hydra ASICs) where a zero
* at the input to the receiver becomes 'stuck' and locks up the receiver.
* This problem can occur as a result of a zero bit at the receiver input
* coincident with any of the following events:
*
* The SCC is initialized (hardware or software).
* A framing error is detected.
* The clocking option changes from synchronous or X1 asynchronous
* clocking to X16, X32, or X64 asynchronous clocking.
* The decoding mode is changed among NRZ, NRZI, FM0, or FM1.
*
* This workaround attempts to recover from the lockup condition by placing
* the SCC in synchronous loopback mode with a fast clock before programming
* any of the asynchronous modes.
*/
static void pmz_fix_zero_bug_scc(struct uart_pmac_port *uap)
{
write_zsreg(uap, 9, ZS_IS_CHANNEL_A(uap) ? CHRA : CHRB);
zssync(uap);
udelay(10);
write_zsreg(uap, 9, (ZS_IS_CHANNEL_A(uap) ? CHRA : CHRB) | NV);
zssync(uap);
write_zsreg(uap, 4, X1CLK | MONSYNC);
write_zsreg(uap, 3, Rx8);
write_zsreg(uap, 5, Tx8 | RTS);
write_zsreg(uap, 9, NV); /* Didn't we already do this? */
write_zsreg(uap, 11, RCBR | TCBR);
write_zsreg(uap, 12, 0);
write_zsreg(uap, 13, 0);
write_zsreg(uap, 14, (LOOPBAK | BRSRC));
write_zsreg(uap, 14, (LOOPBAK | BRSRC | BRENAB));
write_zsreg(uap, 3, Rx8 | RxENABLE);
write_zsreg(uap, 0, RES_EXT_INT);
write_zsreg(uap, 0, RES_EXT_INT);
write_zsreg(uap, 0, RES_EXT_INT); /* to kill some time */
/* The channel should be OK now, but it is probably receiving
* loopback garbage.
* Switch to asynchronous mode, disable the receiver,
* and discard everything in the receive buffer.
*/
write_zsreg(uap, 9, NV);
write_zsreg(uap, 4, X16CLK | SB_MASK);
write_zsreg(uap, 3, Rx8);
while (read_zsreg(uap, 0) & Rx_CH_AV) {
(void)read_zsreg(uap, 8);
write_zsreg(uap, 0, RES_EXT_INT);
write_zsreg(uap, 0, ERR_RES);
}
}
/*
* Real startup routine, powers up the hardware and sets up
* the SCC. Returns a delay in ms where you need to wait before
* actually using the port, this is typically the internal modem
* powerup delay. This routine expect the lock to be taken.
*/
static int __pmz_startup(struct uart_pmac_port *uap)
{
int pwr_delay = 0;
memset(&uap->curregs, 0, sizeof(uap->curregs));
/* Power up the SCC & underlying hardware (modem/irda) */
pwr_delay = pmz_set_scc_power(uap, 1);
/* Nice buggy HW ... */
pmz_fix_zero_bug_scc(uap);
/* Reset the channel */
uap->curregs[R9] = 0;
write_zsreg(uap, 9, ZS_IS_CHANNEL_A(uap) ? CHRA : CHRB);
zssync(uap);
udelay(10);
write_zsreg(uap, 9, 0);
zssync(uap);
/* Clear the interrupt registers */
write_zsreg(uap, R1, 0);
write_zsreg(uap, R0, ERR_RES);
write_zsreg(uap, R0, ERR_RES);
write_zsreg(uap, R0, RES_H_IUS);
write_zsreg(uap, R0, RES_H_IUS);
/* Setup some valid baud rate */
uap->curregs[R4] = X16CLK | SB1;
uap->curregs[R3] = Rx8;
uap->curregs[R5] = Tx8 | RTS;
if (!ZS_IS_IRDA(uap))
uap->curregs[R5] |= DTR;
uap->curregs[R12] = 0;
uap->curregs[R13] = 0;
uap->curregs[R14] = BRENAB;
/* Clear handshaking, enable BREAK interrupts */
uap->curregs[R15] = BRKIE;
/* Master interrupt enable */
uap->curregs[R9] |= NV | MIE;
pmz_load_zsregs(uap, uap->curregs);
/* Enable receiver and transmitter. */
write_zsreg(uap, R3, uap->curregs[R3] |= RxENABLE);
write_zsreg(uap, R5, uap->curregs[R5] |= TxENABLE);
/* Remember status for DCD/CTS changes */
uap->prev_status = read_zsreg(uap, R0);
return pwr_delay;
}
static void pmz_irda_reset(struct uart_pmac_port *uap)
{
uap->curregs[R5] |= DTR;
write_zsreg(uap, R5, uap->curregs[R5]);
zssync(uap);
mdelay(110);
uap->curregs[R5] &= ~DTR;
write_zsreg(uap, R5, uap->curregs[R5]);
zssync(uap);
mdelay(10);
}
/*
* This is the "normal" startup routine, using the above one
* wrapped with the lock and doing a schedule delay
*/
static int pmz_startup(struct uart_port *port)
{
struct uart_pmac_port *uap = to_pmz(port);
unsigned long flags;
int pwr_delay = 0;
pmz_debug("pmz: startup()\n");
if (ZS_IS_ASLEEP(uap))
return -EAGAIN;
if (uap->node == NULL)
return -ENODEV;
mutex_lock(&pmz_irq_mutex);
uap->flags |= PMACZILOG_FLAG_IS_OPEN;
/* A console is never powered down. Else, power up and
* initialize the chip
*/
if (!ZS_IS_CONS(uap)) {
spin_lock_irqsave(&port->lock, flags);
pwr_delay = __pmz_startup(uap);
spin_unlock_irqrestore(&port->lock, flags);
}
pmz_get_port_A(uap)->flags |= PMACZILOG_FLAG_IS_IRQ_ON;
if (request_irq(uap->port.irq, pmz_interrupt, IRQF_SHARED, "PowerMac Zilog", uap)) {
dev_err(&uap->dev->ofdev.dev,
"Unable to register zs interrupt handler.\n");
pmz_set_scc_power(uap, 0);
mutex_unlock(&pmz_irq_mutex);
return -ENXIO;
}
mutex_unlock(&pmz_irq_mutex);
/* Right now, we deal with delay by blocking here, I'll be
* smarter later on
*/
if (pwr_delay != 0) {
pmz_debug("pmz: delaying %d ms\n", pwr_delay);
msleep(pwr_delay);
}
/* IrDA reset is done now */
if (ZS_IS_IRDA(uap))
pmz_irda_reset(uap);
/* Enable interrupts emission from the chip */
spin_lock_irqsave(&port->lock, flags);
uap->curregs[R1] |= INT_ALL_Rx | TxINT_ENAB;
if (!ZS_IS_EXTCLK(uap))
uap->curregs[R1] |= EXT_INT_ENAB;
write_zsreg(uap, R1, uap->curregs[R1]);
spin_unlock_irqrestore(&port->lock, flags);
pmz_debug("pmz: startup() done.\n");
return 0;
}
static void pmz_shutdown(struct uart_port *port)
{
struct uart_pmac_port *uap = to_pmz(port);
unsigned long flags;
pmz_debug("pmz: shutdown()\n");
if (uap->node == NULL)
return;
mutex_lock(&pmz_irq_mutex);
/* Release interrupt handler */
free_irq(uap->port.irq, uap);
spin_lock_irqsave(&port->lock, flags);
uap->flags &= ~PMACZILOG_FLAG_IS_OPEN;