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linux_dsm_epyc7002/drivers/serial/zs.c
Maciej W. Rozycki 3771359128 serial: Z85C30: avoid a hang at console switch-over 
Changes to the generic console support code that happened a while ago
introduced a scenario where the initial console is used in parallel with
the final console during a brief period when switching between the two is
in progress.  During that time a message about the switch-over is printed.

With some combinations of chips, firmware and drivers, such as the Zilog
Z85C30 SCC used with the DECstation, a hang may happen because the
firmware used for the initial console may not expect the state of the chip
after it has been initialised by the driver.  This is not a bug in the
firmware, as some registers it would have to examine are write-only.

This is a workaround for the Z85C30 which reuses the power-management
callback to keep the transmitter of the line associated with the console
enabled.  It reflects the consensus reached in a discussion a while ago.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24 10:47:29 -07:00

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/*
* zs.c: Serial port driver for IOASIC DECstations.
*
* Derived from drivers/sbus/char/sunserial.c by Paul Mackerras.
* Derived from drivers/macintosh/macserial.c by Harald Koerfgen.
*
* DECstation changes
* Copyright (C) 1998-2000 Harald Koerfgen
* Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007 Maciej W. Rozycki
*
* For the rest of the code the original Copyright applies:
* Copyright (C) 1996 Paul Mackerras (Paul.Mackerras@cs.anu.edu.au)
* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
*
*
* Note: for IOASIC systems the wiring is as follows:
*
* mouse/keyboard:
* DIN-7 MJ-4 signal SCC
* 2 1 TxD <- A.TxD
* 3 4 RxD -> A.RxD
*
* EIA-232/EIA-423:
* DB-25 MMJ-6 signal SCC
* 2 2 TxD <- B.TxD
* 3 5 RxD -> B.RxD
* 4 RTS <- ~A.RTS
* 5 CTS -> ~B.CTS
* 6 6 DSR -> ~A.SYNC
* 8 CD -> ~B.DCD
* 12 DSRS(DCE) -> ~A.CTS (*)
* 15 TxC -> B.TxC
* 17 RxC -> B.RxC
* 20 1 DTR <- ~A.DTR
* 22 RI -> ~A.DCD
* 23 DSRS(DTE) <- ~B.RTS
*
* (*) EIA-232 defines the signal at this pin to be SCD, while DSRS(DCE)
* is shared with DSRS(DTE) at pin 23.
*
* As you can immediately notice the wiring of the RTS, DTR and DSR signals
* is a bit odd. This makes the handling of port B unnecessarily
* complicated and prevents the use of some automatic modes of operation.
*/
#if defined(CONFIG_SERIAL_ZS_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif
#include <linux/bug.h>
#include <linux/console.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/irqflags.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/spinlock.h>
#include <linux/sysrq.h>
#include <linux/tty.h>
#include <linux/types.h>
#include <asm/atomic.h>
#include <asm/system.h>
#include <asm/dec/interrupts.h>
#include <asm/dec/ioasic_addrs.h>
#include <asm/dec/system.h>
#include "zs.h"
MODULE_AUTHOR("Maciej W. Rozycki <macro@linux-mips.org>");
MODULE_DESCRIPTION("DECstation Z85C30 serial driver");
MODULE_LICENSE("GPL");
static char zs_name[] __initdata = "DECstation Z85C30 serial driver version ";
static char zs_version[] __initdata = "0.10";
/*
* It would be nice to dynamically allocate everything that
* depends on ZS_NUM_SCCS, so we could support any number of
* Z85C30s, but for now...
*/
#define ZS_NUM_SCCS 2 /* Max # of ZS chips supported. */
#define ZS_NUM_CHAN 2 /* 2 channels per chip. */
#define ZS_CHAN_A 0 /* Index of the channel A. */
#define ZS_CHAN_B 1 /* Index of the channel B. */
#define ZS_CHAN_IO_SIZE 8 /* IOMEM space size. */
#define ZS_CHAN_IO_STRIDE 4 /* Register alignment. */
#define ZS_CHAN_IO_OFFSET 1 /* The SCC resides on the high byte
of the 16-bit IOBUS. */
#define ZS_CLOCK 7372800 /* Z85C30 PCLK input clock rate. */
#define to_zport(uport) container_of(uport, struct zs_port, port)
struct zs_parms {
resource_size_t scc[ZS_NUM_SCCS];
int irq[ZS_NUM_SCCS];
};
static struct zs_scc zs_sccs[ZS_NUM_SCCS];
static u8 zs_init_regs[ZS_NUM_REGS] __initdata = {
0, /* write 0 */
PAR_SPEC, /* write 1 */
0, /* write 2 */
0, /* write 3 */
X16CLK | SB1, /* write 4 */
0, /* write 5 */
0, 0, 0, /* write 6, 7, 8 */
MIE | DLC | NV, /* write 9 */
NRZ, /* write 10 */
TCBR | RCBR, /* write 11 */
0, 0, /* BRG time constant, write 12 + 13 */
BRSRC | BRENABL, /* write 14 */
0, /* write 15 */
};
/*
* Debugging.
*/
#undef ZS_DEBUG_REGS
/*
* Reading and writing Z85C30 registers.
*/
static void recovery_delay(void)
{
udelay(2);
}
static u8 read_zsreg(struct zs_port *zport, int reg)
{
void __iomem *control = zport->port.membase + ZS_CHAN_IO_OFFSET;
u8 retval;
if (reg != 0) {
writeb(reg & 0xf, control);
fast_iob();
recovery_delay();
}
retval = readb(control);
recovery_delay();
return retval;
}
static void write_zsreg(struct zs_port *zport, int reg, u8 value)
{
void __iomem *control = zport->port.membase + ZS_CHAN_IO_OFFSET;
if (reg != 0) {
writeb(reg & 0xf, control);
fast_iob(); recovery_delay();
}
writeb(value, control);
fast_iob();
recovery_delay();
return;
}
static u8 read_zsdata(struct zs_port *zport)
{
void __iomem *data = zport->port.membase +
ZS_CHAN_IO_STRIDE + ZS_CHAN_IO_OFFSET;
u8 retval;
retval = readb(data);
recovery_delay();
return retval;
}
static void write_zsdata(struct zs_port *zport, u8 value)
{
void __iomem *data = zport->port.membase +
ZS_CHAN_IO_STRIDE + ZS_CHAN_IO_OFFSET;
writeb(value, data);
fast_iob();
recovery_delay();
return;
}
#ifdef ZS_DEBUG_REGS
void zs_dump(void)
{
struct zs_port *zport;
int i, j;
for (i = 0; i < ZS_NUM_SCCS * ZS_NUM_CHAN; i++) {
zport = &zs_sccs[i / ZS_NUM_CHAN].zport[i % ZS_NUM_CHAN];
if (!zport->scc)
continue;
for (j = 0; j < 16; j++)
printk("W%-2d = 0x%02x\t", j, zport->regs[j]);
printk("\n");
for (j = 0; j < 16; j++)
printk("R%-2d = 0x%02x\t", j, read_zsreg(zport, j));
printk("\n\n");
}
}
#endif
static void zs_spin_lock_cond_irq(spinlock_t *lock, int irq)
{
if (irq)
spin_lock_irq(lock);
else
spin_lock(lock);
}
static void zs_spin_unlock_cond_irq(spinlock_t *lock, int irq)
{
if (irq)
spin_unlock_irq(lock);
else
spin_unlock(lock);
}
static int zs_receive_drain(struct zs_port *zport)
{
int loops = 10000;
while ((read_zsreg(zport, R0) & Rx_CH_AV) && loops--)
read_zsdata(zport);
return loops;
}
static int zs_transmit_drain(struct zs_port *zport, int irq)
{
struct zs_scc *scc = zport->scc;
int loops = 10000;
while (!(read_zsreg(zport, R0) & Tx_BUF_EMP) && loops--) {
zs_spin_unlock_cond_irq(&scc->zlock, irq);
udelay(2);
zs_spin_lock_cond_irq(&scc->zlock, irq);
}
return loops;
}
static int zs_line_drain(struct zs_port *zport, int irq)
{
struct zs_scc *scc = zport->scc;
int loops = 10000;
while (!(read_zsreg(zport, R1) & ALL_SNT) && loops--) {
zs_spin_unlock_cond_irq(&scc->zlock, irq);
udelay(2);
zs_spin_lock_cond_irq(&scc->zlock, irq);
}
return loops;
}
static void load_zsregs(struct zs_port *zport, u8 *regs, int irq)
{
/* Let the current transmission finish. */
zs_line_drain(zport, irq);
/* Load 'em up. */
write_zsreg(zport, R3, regs[3] & ~RxENABLE);
write_zsreg(zport, R5, regs[5] & ~TxENAB);
write_zsreg(zport, R4, regs[4]);
write_zsreg(zport, R9, regs[9]);
write_zsreg(zport, R1, regs[1]);
write_zsreg(zport, R2, regs[2]);
write_zsreg(zport, R10, regs[10]);
write_zsreg(zport, R14, regs[14] & ~BRENABL);
write_zsreg(zport, R11, regs[11]);
write_zsreg(zport, R12, regs[12]);
write_zsreg(zport, R13, regs[13]);
write_zsreg(zport, R14, regs[14]);
write_zsreg(zport, R15, regs[15]);
if (regs[3] & RxENABLE)
write_zsreg(zport, R3, regs[3]);
if (regs[5] & TxENAB)
write_zsreg(zport, R5, regs[5]);
return;
}
/*
* Status handling routines.
*/
/*
* zs_tx_empty() -- get the transmitter empty status
*
* Purpose: Let user call ioctl() to get info when the UART physically
* is emptied. On bus types like RS485, the transmitter must
* release the bus after transmitting. This must be done when
* the transmit shift register is empty, not be done when the
* transmit holding register is empty. This functionality
* allows an RS485 driver to be written in user space.
*/
static unsigned int zs_tx_empty(struct uart_port *uport)
{
struct zs_port *zport = to_zport(uport);
struct zs_scc *scc = zport->scc;
unsigned long flags;
u8 status;
spin_lock_irqsave(&scc->zlock, flags);
status = read_zsreg(zport, R1);
spin_unlock_irqrestore(&scc->zlock, flags);
return status & ALL_SNT ? TIOCSER_TEMT : 0;
}
static unsigned int zs_raw_get_ab_mctrl(struct zs_port *zport_a,
struct zs_port *zport_b)
{
u8 status_a, status_b;
unsigned int mctrl;
status_a = read_zsreg(zport_a, R0);
status_b = read_zsreg(zport_b, R0);
mctrl = ((status_b & CTS) ? TIOCM_CTS : 0) |
((status_b & DCD) ? TIOCM_CAR : 0) |
((status_a & DCD) ? TIOCM_RNG : 0) |
((status_a & SYNC_HUNT) ? TIOCM_DSR : 0);
return mctrl;
}
static unsigned int zs_raw_get_mctrl(struct zs_port *zport)
{
struct zs_port *zport_a = &zport->scc->zport[ZS_CHAN_A];
return zport != zport_a ? zs_raw_get_ab_mctrl(zport_a, zport) : 0;
}
static unsigned int zs_raw_xor_mctrl(struct zs_port *zport)
{
struct zs_port *zport_a = &zport->scc->zport[ZS_CHAN_A];
unsigned int mmask, mctrl, delta;
u8 mask_a, mask_b;
if (zport == zport_a)
return 0;
mask_a = zport_a->regs[15];
mask_b = zport->regs[15];
mmask = ((mask_b & CTSIE) ? TIOCM_CTS : 0) |
((mask_b & DCDIE) ? TIOCM_CAR : 0) |
((mask_a & DCDIE) ? TIOCM_RNG : 0) |
((mask_a & SYNCIE) ? TIOCM_DSR : 0);
mctrl = zport->mctrl;
if (mmask) {
mctrl &= ~mmask;
mctrl |= zs_raw_get_ab_mctrl(zport_a, zport) & mmask;
}
delta = mctrl ^ zport->mctrl;
if (delta)
zport->mctrl = mctrl;
return delta;
}
static unsigned int zs_get_mctrl(struct uart_port *uport)
{
struct zs_port *zport = to_zport(uport);
struct zs_scc *scc = zport->scc;
unsigned int mctrl;
spin_lock(&scc->zlock);
mctrl = zs_raw_get_mctrl(zport);
spin_unlock(&scc->zlock);
return mctrl;
}
static void zs_set_mctrl(struct uart_port *uport, unsigned int mctrl)
{
struct zs_port *zport = to_zport(uport);
struct zs_scc *scc = zport->scc;
struct zs_port *zport_a = &scc->zport[ZS_CHAN_A];
u8 oldloop, newloop;
spin_lock(&scc->zlock);
if (zport != zport_a) {
if (mctrl & TIOCM_DTR)
zport_a->regs[5] |= DTR;
else
zport_a->regs[5] &= ~DTR;
if (mctrl & TIOCM_RTS)
zport_a->regs[5] |= RTS;
else
zport_a->regs[5] &= ~RTS;
write_zsreg(zport_a, R5, zport_a->regs[5]);
}
/* Rarely modified, so don't poke at hardware unless necessary. */
oldloop = zport->regs[14];
newloop = oldloop;
if (mctrl & TIOCM_LOOP)
newloop |= LOOPBAK;
else
newloop &= ~LOOPBAK;
if (newloop != oldloop) {
zport->regs[14] = newloop;
write_zsreg(zport, R14, zport->regs[14]);
}
spin_unlock(&scc->zlock);
}
static void zs_raw_stop_tx(struct zs_port *zport)
{
write_zsreg(zport, R0, RES_Tx_P);
zport->tx_stopped = 1;
}
static void zs_stop_tx(struct uart_port *uport)
{
struct zs_port *zport = to_zport(uport);
struct zs_scc *scc = zport->scc;
spin_lock(&scc->zlock);
zs_raw_stop_tx(zport);
spin_unlock(&scc->zlock);
}
static void zs_raw_transmit_chars(struct zs_port *);
static void zs_start_tx(struct uart_port *uport)
{
struct zs_port *zport = to_zport(uport);
struct zs_scc *scc = zport->scc;
spin_lock(&scc->zlock);
if (zport->tx_stopped) {
zs_transmit_drain(zport, 0);
zport->tx_stopped = 0;
zs_raw_transmit_chars(zport);
}
spin_unlock(&scc->zlock);
}
static void zs_stop_rx(struct uart_port *uport)
{
struct zs_port *zport = to_zport(uport);
struct zs_scc *scc = zport->scc;
struct zs_port *zport_a = &scc->zport[ZS_CHAN_A];
spin_lock(&scc->zlock);
zport->regs[15] &= ~BRKIE;
zport->regs[1] &= ~(RxINT_MASK | TxINT_ENAB);
zport->regs[1] |= RxINT_DISAB;
if (zport != zport_a) {
/* A-side DCD tracks RI and SYNC tracks DSR. */
zport_a->regs[15] &= ~(DCDIE | SYNCIE);
write_zsreg(zport_a, R15, zport_a->regs[15]);
if (!(zport_a->regs[15] & BRKIE)) {
zport_a->regs[1] &= ~EXT_INT_ENAB;
write_zsreg(zport_a, R1, zport_a->regs[1]);
}
/* This-side DCD tracks DCD and CTS tracks CTS. */
zport->regs[15] &= ~(DCDIE | CTSIE);
zport->regs[1] &= ~EXT_INT_ENAB;
} else {
/* DCD tracks RI and SYNC tracks DSR for the B side. */
if (!(zport->regs[15] & (DCDIE | SYNCIE)))
zport->regs[1] &= ~EXT_INT_ENAB;
}
write_zsreg(zport, R15, zport->regs[15]);
write_zsreg(zport, R1, zport->regs[1]);
spin_unlock(&scc->zlock);
}
static void zs_enable_ms(struct uart_port *uport)
{
struct zs_port *zport = to_zport(uport);
struct zs_scc *scc = zport->scc;
struct zs_port *zport_a = &scc->zport[ZS_CHAN_A];
if (zport == zport_a)
return;
spin_lock(&scc->zlock);
/* Clear Ext interrupts if not being handled already. */
if (!(zport_a->regs[1] & EXT_INT_ENAB))
write_zsreg(zport_a, R0, RES_EXT_INT);
/* A-side DCD tracks RI and SYNC tracks DSR. */
zport_a->regs[1] |= EXT_INT_ENAB;
zport_a->regs[15] |= DCDIE | SYNCIE;
/* This-side DCD tracks DCD and CTS tracks CTS. */
zport->regs[15] |= DCDIE | CTSIE;
zs_raw_xor_mctrl(zport);
write_zsreg(zport_a, R1, zport_a->regs[1]);
write_zsreg(zport_a, R15, zport_a->regs[15]);
write_zsreg(zport, R15, zport->regs[15]);
spin_unlock(&scc->zlock);
}
static void zs_break_ctl(struct uart_port *uport, int break_state)
{
struct zs_port *zport = to_zport(uport);
struct zs_scc *scc = zport->scc;
unsigned long flags;
spin_lock_irqsave(&scc->zlock, flags);
if (break_state == -1)
zport->regs[5] |= SND_BRK;
else
zport->regs[5] &= ~SND_BRK;
write_zsreg(zport, R5, zport->regs[5]);
spin_unlock_irqrestore(&scc->zlock, flags);
}
/*
* Interrupt handling routines.
*/
#define Rx_BRK 0x0100 /* BREAK event software flag. */
#define Rx_SYS 0x0200 /* SysRq event software flag. */
static void zs_receive_chars(struct zs_port *zport)
{
struct uart_port *uport = &zport->port;
struct zs_scc *scc = zport->scc;
struct uart_icount *icount;
unsigned int avail, status, ch, flag;
int count;
for (count = 16; count; count--) {
spin_lock(&scc->zlock);
avail = read_zsreg(zport, R0) & Rx_CH_AV;
spin_unlock(&scc->zlock);
if (!avail)
break;
spin_lock(&scc->zlock);
status = read_zsreg(zport, R1) & (Rx_OVR | FRM_ERR | PAR_ERR);
ch = read_zsdata(zport);
spin_unlock(&scc->zlock);
flag = TTY_NORMAL;
icount = &uport->icount;
icount->rx++;
/* Handle the null char got when BREAK is removed. */
if (!ch)
status |= zport->tty_break;
if (unlikely(status &
(Rx_OVR | FRM_ERR | PAR_ERR | Rx_SYS | Rx_BRK))) {
zport->tty_break = 0;
/* Reset the error indication. */
if (status & (Rx_OVR | FRM_ERR | PAR_ERR)) {
spin_lock(&scc->zlock);
write_zsreg(zport, R0, ERR_RES);
spin_unlock(&scc->zlock);
}
if (status & (Rx_SYS | Rx_BRK)) {
icount->brk++;
/* SysRq discards the null char. */
if (status & Rx_SYS)
continue;
} else if (status & FRM_ERR)
icount->frame++;
else if (status & PAR_ERR)
icount->parity++;
if (status & Rx_OVR)
icount->overrun++;
status &= uport->read_status_mask;
if (status & Rx_BRK)
flag = TTY_BREAK;
else if (status & FRM_ERR)
flag = TTY_FRAME;
else if (status & PAR_ERR)
flag = TTY_PARITY;
}
if (uart_handle_sysrq_char(uport, ch))
continue;
uart_insert_char(uport, status, Rx_OVR, ch, flag);
}
tty_flip_buffer_push(uport->info->port.tty);
}
static void zs_raw_transmit_chars(struct zs_port *zport)
{
struct circ_buf *xmit = &zport->port.info->xmit;
/* XON/XOFF chars. */
if (zport->port.x_char) {
write_zsdata(zport, zport->port.x_char);
zport->port.icount.tx++;
zport->port.x_char = 0;
return;
}
/* If nothing to do or stopped or hardware stopped. */
if (uart_circ_empty(xmit) || uart_tx_stopped(&zport->port)) {
zs_raw_stop_tx(zport);
return;
}
/* Send char. */
write_zsdata(zport, xmit->buf[xmit->tail]);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
zport->port.icount.tx++;
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&zport->port);
/* Are we are done? */
if (uart_circ_empty(xmit))
zs_raw_stop_tx(zport);
}
static void zs_transmit_chars(struct zs_port *zport)
{
struct zs_scc *scc = zport->scc;
spin_lock(&scc->zlock);
zs_raw_transmit_chars(zport);
spin_unlock(&scc->zlock);
}
static void zs_status_handle(struct zs_port *zport, struct zs_port *zport_a)
{
struct uart_port *uport = &zport->port;
struct zs_scc *scc = zport->scc;
unsigned int delta;
u8 status, brk;
spin_lock(&scc->zlock);
/* Get status from Read Register 0. */
status = read_zsreg(zport, R0);
if (zport->regs[15] & BRKIE) {
brk = status & BRK_ABRT;
if (brk && !zport->brk) {
spin_unlock(&scc->zlock);
if (uart_handle_break(uport))
zport->tty_break = Rx_SYS;
else
zport->tty_break = Rx_BRK;
spin_lock(&scc->zlock);
}
zport->brk = brk;
}
if (zport != zport_a) {
delta = zs_raw_xor_mctrl(zport);
spin_unlock(&scc->zlock);
if (delta & TIOCM_CTS)
uart_handle_cts_change(uport,
zport->mctrl & TIOCM_CTS);
if (delta & TIOCM_CAR)
uart_handle_dcd_change(uport,
zport->mctrl & TIOCM_CAR);
if (delta & TIOCM_RNG)
uport->icount.dsr++;
if (delta & TIOCM_DSR)
uport->icount.rng++;
if (delta)
wake_up_interruptible(&uport->info->delta_msr_wait);
spin_lock(&scc->zlock);
}
/* Clear the status condition... */
write_zsreg(zport, R0, RES_EXT_INT);
spin_unlock(&scc->zlock);
}
/*
* This is the Z85C30 driver's generic interrupt routine.
*/
static irqreturn_t zs_interrupt(int irq, void *dev_id)
{
struct zs_scc *scc = dev_id;
struct zs_port *zport_a = &scc->zport[ZS_CHAN_A];
struct zs_port *zport_b = &scc->zport[ZS_CHAN_B];
irqreturn_t status = IRQ_NONE;
u8 zs_intreg;
int count;
/*
* NOTE: The read register 3, which holds the irq status,
* does so for both channels on each chip. Although
* the status value itself must be read from the A
* channel and is only valid when read from channel A.
* Yes... broken hardware...
*/
for (count = 16; count; count--) {
spin_lock(&scc->zlock);
zs_intreg = read_zsreg(zport_a, R3);
spin_unlock(&scc->zlock);
if (!zs_intreg)
break;
/*
* We do not like losing characters, so we prioritise
* interrupt sources a little bit differently than
* the SCC would, was it allowed to.
*/
if (zs_intreg & CHBRxIP)
zs_receive_chars(zport_b);
if (zs_intreg & CHARxIP)
zs_receive_chars(zport_a);
if (zs_intreg & CHBEXT)
zs_status_handle(zport_b, zport_a);
if (zs_intreg & CHAEXT)
zs_status_handle(zport_a, zport_a);
if (zs_intreg & CHBTxIP)
zs_transmit_chars(zport_b);
if (zs_intreg & CHATxIP)
zs_transmit_chars(zport_a);
status = IRQ_HANDLED;
}
return status;
}
/*
* Finally, routines used to initialize the serial port.
*/
static int zs_startup(struct uart_port *uport)
{
struct zs_port *zport = to_zport(uport);
struct zs_scc *scc = zport->scc;
unsigned long flags;
int irq_guard;
int ret;
irq_guard = atomic_add_return(1, &scc->irq_guard);
if (irq_guard == 1) {
ret = request_irq(zport->port.irq, zs_interrupt,
IRQF_SHARED, "scc", scc);
if (ret) {
atomic_add(-1, &scc->irq_guard);
printk(KERN_ERR "zs: can't get irq %d\n",
zport->port.irq);
return ret;
}
}
spin_lock_irqsave(&scc->zlock, flags);
/* Clear the receive FIFO. */
zs_receive_drain(zport);
/* Clear the interrupt registers. */
write_zsreg(zport, R0, ERR_RES);
write_zsreg(zport, R0, RES_Tx_P);
/* But Ext only if not being handled already. */
if (!(zport->regs[1] & EXT_INT_ENAB))
write_zsreg(zport, R0, RES_EXT_INT);
/* Finally, enable sequencing and interrupts. */
zport->regs[1] &= ~RxINT_MASK;
zport->regs[1] |= RxINT_ALL | TxINT_ENAB | EXT_INT_ENAB;
zport->regs[3] |= RxENABLE;
zport->regs[15] |= BRKIE;
write_zsreg(zport, R1, zport->regs[1]);
write_zsreg(zport, R3, zport->regs[3]);
write_zsreg(zport, R5, zport->regs[5]);
write_zsreg(zport, R15, zport->regs[15]);
/* Record the current state of RR0. */
zport->mctrl = zs_raw_get_mctrl(zport);
zport->brk = read_zsreg(zport, R0) & BRK_ABRT;
zport->tx_stopped = 1;
spin_unlock_irqrestore(&scc->zlock, flags);
return 0;
}
static void zs_shutdown(struct uart_port *uport)
{
struct zs_port *zport = to_zport(uport);
struct zs_scc *scc = zport->scc;
unsigned long flags;
int irq_guard;
spin_lock_irqsave(&scc->zlock, flags);
zport->regs[3] &= ~RxENABLE;
write_zsreg(zport, R5, zport->regs[5]);
write_zsreg(zport, R3, zport->regs[3]);
spin_unlock_irqrestore(&scc->zlock, flags);
irq_guard = atomic_add_return(-1, &scc->irq_guard);
if (!irq_guard)
free_irq(zport->port.irq, scc);
}
static void zs_reset(struct zs_port *zport)
{
struct zs_scc *scc = zport->scc;
int irq;
unsigned long flags;
spin_lock_irqsave(&scc->zlock, flags);
irq = !irqs_disabled_flags(flags);
if (!scc->initialised) {
/* Reset the pointer first, just in case... */
read_zsreg(zport, R0);
/* And let the current transmission finish. */
zs_line_drain(zport, irq);
write_zsreg(zport, R9, FHWRES);
udelay(10);
write_zsreg(zport, R9, 0);
scc->initialised = 1;
}
load_zsregs(zport, zport->regs, irq);
spin_unlock_irqrestore(&scc->zlock, flags);
}
static void zs_set_termios(struct uart_port *uport, struct ktermios *termios,
struct ktermios *old_termios)
{
struct zs_port *zport = to_zport(uport);
struct zs_scc *scc = zport->scc;
struct zs_port *zport_a = &scc->zport[ZS_CHAN_A];
int irq;
unsigned int baud, brg;
unsigned long flags;
spin_lock_irqsave(&scc->zlock, flags);
irq = !irqs_disabled_flags(flags);
/* Byte size. */
zport->regs[3] &= ~RxNBITS_MASK;
zport->regs[5] &= ~TxNBITS_MASK;
switch (termios->c_cflag & CSIZE) {
case CS5:
zport->regs[3] |= Rx5;
zport->regs[5] |= Tx5;
break;
case CS6:
zport->regs[3] |= Rx6;
zport->regs[5] |= Tx6;
break;
case CS7:
zport->regs[3] |= Rx7;
zport->regs[5] |= Tx7;
break;
case CS8:
default:
zport->regs[3] |= Rx8;
zport->regs[5] |= Tx8;
break;
}
/* Parity and stop bits. */
zport->regs[4] &= ~(XCLK_MASK | SB_MASK | PAR_ENA | PAR_EVEN);
if (termios->c_cflag & CSTOPB)
zport->regs[4] |= SB2;
else
zport->regs[4] |= SB1;
if (termios->c_cflag & PARENB)
zport->regs[4] |= PAR_ENA;
if (!(termios->c_cflag & PARODD))
zport->regs[4] |= PAR_EVEN;
switch (zport->clk_mode) {
case 64:
zport->regs[4] |= X64CLK;
break;
case 32:
zport->regs[4] |= X32CLK;
break;
case 16:
zport->regs[4] |= X16CLK;
break;
case 1:
zport->regs[4] |= X1CLK;
break;
default:
BUG();
}
baud = uart_get_baud_rate(uport, termios, old_termios, 0,
uport->uartclk / zport->clk_mode / 4);
brg = ZS_BPS_TO_BRG(baud, uport->uartclk / zport->clk_mode);
zport->regs[12] = brg & 0xff;
zport->regs[13] = (brg >> 8) & 0xff;
uart_update_timeout(uport, termios->c_cflag, baud);
uport->read_status_mask = Rx_OVR;
if (termios->c_iflag & INPCK)
uport->read_status_mask |= FRM_ERR | PAR_ERR;
if (termios->c_iflag & (BRKINT | PARMRK))
uport->read_status_mask |= Rx_BRK;
uport->ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
uport->ignore_status_mask |= FRM_ERR | PAR_ERR;
if (termios->c_iflag & IGNBRK) {
uport->ignore_status_mask |= Rx_BRK;
if (termios->c_iflag & IGNPAR)
uport->ignore_status_mask |= Rx_OVR;
}
if (termios->c_cflag & CREAD)
zport->regs[3] |= RxENABLE;
else
zport->regs[3] &= ~RxENABLE;
if (zport != zport_a) {
if (!(termios->c_cflag & CLOCAL)) {
zport->regs[15] |= DCDIE;
} else
zport->regs[15] &= ~DCDIE;
if (termios->c_cflag & CRTSCTS) {
zport->regs[15] |= CTSIE;
} else
zport->regs[15] &= ~CTSIE;
zs_raw_xor_mctrl(zport);
}
/* Load up the new values. */
load_zsregs(zport, zport->regs, irq);
spin_unlock_irqrestore(&scc->zlock, flags);
}
/*
* Hack alert!
* Required solely so that the initial PROM-based console
* works undisturbed in parallel with this one.
*/
static void zs_pm(struct uart_port *uport, unsigned int state,
unsigned int oldstate)
{
struct zs_port *zport = to_zport(uport);
if (state < 3)
zport->regs[5] |= TxENAB;
else
zport->regs[5] &= ~TxENAB;
write_zsreg(zport, R5, zport->regs[5]);
}
static const char *zs_type(struct uart_port *uport)
{
return "Z85C30 SCC";
}
static void zs_release_port(struct uart_port *uport)
{
iounmap(uport->membase);
uport->membase = 0;
release_mem_region(uport->mapbase, ZS_CHAN_IO_SIZE);
}
static int zs_map_port(struct uart_port *uport)
{
if (!uport->membase)
uport->membase = ioremap_nocache(uport->mapbase,
ZS_CHAN_IO_SIZE);
if (!uport->membase) {
printk(KERN_ERR "zs: Cannot map MMIO\n");
return -ENOMEM;
}
return 0;
}
static int zs_request_port(struct uart_port *uport)
{
int ret;
if (!request_mem_region(uport->mapbase, ZS_CHAN_IO_SIZE, "scc")) {
printk(KERN_ERR "zs: Unable to reserve MMIO resource\n");
return -EBUSY;
}
ret = zs_map_port(uport);
if (ret) {
release_mem_region(uport->mapbase, ZS_CHAN_IO_SIZE);
return ret;
}
return 0;
}
static void zs_config_port(struct uart_port *uport, int flags)
{
struct zs_port *zport = to_zport(uport);
if (flags & UART_CONFIG_TYPE) {
if (zs_request_port(uport))
return;
uport->type = PORT_ZS;
zs_reset(zport);
}
}
static int zs_verify_port(struct uart_port *uport, struct serial_struct *ser)
{
struct zs_port *zport = to_zport(uport);
int ret = 0;
if (ser->type != PORT_UNKNOWN && ser->type != PORT_ZS)
ret = -EINVAL;
if (ser->irq != uport->irq)
ret = -EINVAL;
if (ser->baud_base != uport->uartclk / zport->clk_mode / 4)
ret = -EINVAL;
return ret;
}
static struct uart_ops zs_ops = {
.tx_empty = zs_tx_empty,
.set_mctrl = zs_set_mctrl,
.get_mctrl = zs_get_mctrl,
.stop_tx = zs_stop_tx,
.start_tx = zs_start_tx,
.stop_rx = zs_stop_rx,
.enable_ms = zs_enable_ms,
.break_ctl = zs_break_ctl,
.startup = zs_startup,
.shutdown = zs_shutdown,
.set_termios = zs_set_termios,
.pm = zs_pm,
.type = zs_type,
.release_port = zs_release_port,
.request_port = zs_request_port,
.config_port = zs_config_port,
.verify_port = zs_verify_port,
};
/*
* Initialize Z85C30 port structures.
*/
static int __init zs_probe_sccs(void)
{
static int probed;
struct zs_parms zs_parms;
int chip, side, irq;
int n_chips = 0;
int i;
if (probed)
return 0;
irq = dec_interrupt[DEC_IRQ_SCC0];
if (irq >= 0) {
zs_parms.scc[n_chips] = IOASIC_SCC0;
zs_parms.irq[n_chips] = dec_interrupt[DEC_IRQ_SCC0];
n_chips++;
}
irq = dec_interrupt[DEC_IRQ_SCC1];
if (irq >= 0) {
zs_parms.scc[n_chips] = IOASIC_SCC1;
zs_parms.irq[n_chips] = dec_interrupt[DEC_IRQ_SCC1];
n_chips++;
}
if (!n_chips)
return -ENXIO;
probed = 1;
for (chip = 0; chip < n_chips; chip++) {
spin_lock_init(&zs_sccs[chip].zlock);
for (side = 0; side < ZS_NUM_CHAN; side++) {
struct zs_port *zport = &zs_sccs[chip].zport[side];
struct uart_port *uport = &zport->port;
zport->scc = &zs_sccs[chip];
zport->clk_mode = 16;
uport->irq = zs_parms.irq[chip];
uport->uartclk = ZS_CLOCK;
uport->fifosize = 1;
uport->iotype = UPIO_MEM;
uport->flags = UPF_BOOT_AUTOCONF;
uport->ops = &zs_ops;
uport->line = chip * ZS_NUM_CHAN + side;
uport->mapbase = dec_kn_slot_base +
zs_parms.scc[chip] +
(side ^ ZS_CHAN_B) * ZS_CHAN_IO_SIZE;
for (i = 0; i < ZS_NUM_REGS; i++)
zport->regs[i] = zs_init_regs[i];
}
}
return 0;
}
#ifdef CONFIG_SERIAL_ZS_CONSOLE
static void zs_console_putchar(struct uart_port *uport, int ch)
{
struct zs_port *zport = to_zport(uport);
struct zs_scc *scc = zport->scc;
int irq;
unsigned long flags;
spin_lock_irqsave(&scc->zlock, flags);
irq = !irqs_disabled_flags(flags);
if (zs_transmit_drain(zport, irq))
write_zsdata(zport, ch);
spin_unlock_irqrestore(&scc->zlock, flags);
}
/*
* Print a string to the serial port trying not to disturb
* any possible real use of the port...
*/
static void zs_console_write(struct console *co, const char *s,
unsigned int count)
{
int chip = co->index / ZS_NUM_CHAN, side = co->index % ZS_NUM_CHAN;
struct zs_port *zport = &zs_sccs[chip].zport[side];
struct zs_scc *scc = zport->scc;
unsigned long flags;
u8 txint, txenb;
int irq;
/* Disable transmit interrupts and enable the transmitter. */
spin_lock_irqsave(&scc->zlock, flags);
txint = zport->regs[1];
txenb = zport->regs[5];
if (txint & TxINT_ENAB) {
zport->regs[1] = txint & ~TxINT_ENAB;
write_zsreg(zport, R1, zport->regs[1]);
}
if (!(txenb & TxENAB)) {
zport->regs[5] = txenb | TxENAB;
write_zsreg(zport, R5, zport->regs[5]);
}
spin_unlock_irqrestore(&scc->zlock, flags);
uart_console_write(&zport->port, s, count, zs_console_putchar);
/* Restore transmit interrupts and the transmitter enable. */
spin_lock_irqsave(&scc->zlock, flags);
irq = !irqs_disabled_flags(flags);
zs_line_drain(zport, irq);
if (!(txenb & TxENAB)) {
zport->regs[5] &= ~TxENAB;
write_zsreg(zport, R5, zport->regs[5]);
}
if (txint & TxINT_ENAB) {
zport->regs[1] |= TxINT_ENAB;
write_zsreg(zport, R1, zport->regs[1]);
}
spin_unlock_irqrestore(&scc->zlock, flags);
}
/*
* Setup serial console baud/bits/parity. We do two things here:
* - construct a cflag setting for the first uart_open()
* - initialise the serial port
* Return non-zero if we didn't find a serial port.
*/
static int __init zs_console_setup(struct console *co, char *options)
{
int chip = co->index / ZS_NUM_CHAN, side = co->index % ZS_NUM_CHAN;
struct zs_port *zport = &zs_sccs[chip].zport[side];
struct uart_port *uport = &zport->port;
int baud = 9600;
int bits = 8;
int parity = 'n';
int flow = 'n';
int ret;
ret = zs_map_port(uport);
if (ret)
return ret;
zs_reset(zport);
zs_pm(uport, 0, -1);
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(uport, co, baud, parity, bits, flow);
}
static struct uart_driver zs_reg;
static struct console zs_console = {
.name = "ttyS",
.write = zs_console_write,
.device = uart_console_device,
.setup = zs_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &zs_reg,
};
/*
* Register console.
*/
static int __init zs_serial_console_init(void)
{
int ret;
ret = zs_probe_sccs();
if (ret)
return ret;
register_console(&zs_console);
return 0;
}
console_initcall(zs_serial_console_init);
#define SERIAL_ZS_CONSOLE &zs_console
#else
#define SERIAL_ZS_CONSOLE NULL
#endif /* CONFIG_SERIAL_ZS_CONSOLE */
static struct uart_driver zs_reg = {
.owner = THIS_MODULE,
.driver_name = "serial",
.dev_name = "ttyS",
.major = TTY_MAJOR,
.minor = 64,
.nr = ZS_NUM_SCCS * ZS_NUM_CHAN,
.cons = SERIAL_ZS_CONSOLE,
};
/* zs_init inits the driver. */
static int __init zs_init(void)
{
int i, ret;
pr_info("%s%s\n", zs_name, zs_version);
/* Find out how many Z85C30 SCCs we have. */
ret = zs_probe_sccs();
if (ret)
return ret;
ret = uart_register_driver(&zs_reg);
if (ret)
return ret;
for (i = 0; i < ZS_NUM_SCCS * ZS_NUM_CHAN; i++) {
struct zs_scc *scc = &zs_sccs[i / ZS_NUM_CHAN];
struct zs_port *zport = &scc->zport[i % ZS_NUM_CHAN];
struct uart_port *uport = &zport->port;
if (zport->scc)
uart_add_one_port(&zs_reg, uport);
}
return 0;
}
static void __exit zs_exit(void)
{
int i;
for (i = ZS_NUM_SCCS * ZS_NUM_CHAN - 1; i >= 0; i--) {
struct zs_scc *scc = &zs_sccs[i / ZS_NUM_CHAN];
struct zs_port *zport = &scc->zport[i % ZS_NUM_CHAN];
struct uart_port *uport = &zport->port;
if (zport->scc)
uart_remove_one_port(&zs_reg, uport);
}
uart_unregister_driver(&zs_reg);
}
module_init(zs_init);
module_exit(zs_exit);
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