static void __ip22zilog_reset(struct uart_ip22zilog_port *up)
{
struct zilog_channel *channel;
int i;
if (up->flags & IP22ZILOG_FLAG_RESET_DONE)
return;
/* Let pending transmits finish. */
channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
for (i = 0; i < 1000; i++) {
unsigned char stat = read_zsreg(channel, R1);
if (stat & ALL_SNT)
break;
udelay(100);
}
if (!ZS_IS_CHANNEL_A(up)) {
up++;
channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
}
write_zsreg(channel, R9, FHWRES);
ZSDELAY_LONG();
(void) read_zsreg(channel, R0);
up->flags |= IP22ZILOG_FLAG_RESET_DONE;
up->next->flags |= IP22ZILOG_FLAG_RESET_DONE;
}
/*
* 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;
}
/*
* 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);
}
}
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);
}
}
