diff options
Diffstat (limited to 'drivers/tty/serial/ip22zilog.c')
| -rw-r--r-- | drivers/tty/serial/ip22zilog.c | 1224 |
1 files changed, 1224 insertions, 0 deletions
diff --git a/drivers/tty/serial/ip22zilog.c b/drivers/tty/serial/ip22zilog.c new file mode 100644 index 000000000..8c810733d --- /dev/null +++ b/drivers/tty/serial/ip22zilog.c @@ -0,0 +1,1224 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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/module.h> +#include <linux/kernel.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" + +/* + * 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 +#define IP22ZILOG_FLAG_RESET_DONE 0x00000200 + + unsigned int tty_break; + + 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); + } + } +} + +#define Rx_BRK 0x0100 /* BREAK event software flag. */ +#define Rx_SYS 0x0200 /* SysRq event software flag. */ + +static bool ip22zilog_receive_chars(struct uart_ip22zilog_port *up, + struct zilog_channel *channel) +{ + unsigned char ch, flag; + unsigned int r1; + bool push = up->port.state != NULL; + + for (;;) { + ch = readb(&channel->control); + ZSDELAY(); + if (!(ch & Rx_CH_AV)) + break; + + 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->data); + ZSDELAY(); + + ch &= up->parity_mask; + + /* Handle the null char got when BREAK is removed. */ + if (!ch) + r1 |= up->tty_break; + + /* A real serial line, record the character and status. */ + flag = TTY_NORMAL; + up->port.icount.rx++; + if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR | Rx_SYS | Rx_BRK)) { + up->tty_break = 0; + + if (r1 & (Rx_SYS | Rx_BRK)) { + up->port.icount.brk++; + if (r1 & Rx_SYS) + continue; + r1 &= ~(PAR_ERR | CRC_ERR); + } + 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 & Rx_BRK) + flag = TTY_BREAK; + else if (r1 & PAR_ERR) + flag = TTY_PARITY; + else if (r1 & CRC_ERR) + flag = TTY_FRAME; + } + + if (uart_handle_sysrq_char(&up->port, ch)) + continue; + + if (push) + uart_insert_char(&up->port, r1, Rx_OVR, ch, flag); + } + return push; +} + +static void ip22zilog_status_handle(struct uart_ip22zilog_port *up, + struct zilog_channel *channel) +{ + unsigned char status; + + status = readb(&channel->control); + ZSDELAY(); + + writeb(RES_EXT_INT, &channel->control); + ZSDELAY(); + ZS_WSYNC(channel); + + if (up->curregs[R15] & BRKIE) { + if ((status & BRK_ABRT) && !(up->prev_status & BRK_ABRT)) { + if (uart_handle_break(&up->port)) + up->tty_break = Rx_SYS; + else + up->tty_break = Rx_BRK; + } + } + + 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 ^ up->prev_status) ^ DCD) + uart_handle_dcd_change(&up->port, + (status & DCD)); + if ((status ^ up->prev_status) ^ CTS) + uart_handle_cts_change(&up->port, + (status & CTS)); + + wake_up_interruptible(&up->port.state->port.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 becoming 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.state == NULL) + goto ack_tx_int; + xmit = &up->port.state->xmit; + if (uart_circ_empty(xmit)) + 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 uart_ip22zilog_port *up = dev_id; + + while (up) { + struct zilog_channel *channel + = ZILOG_CHANNEL_FROM_PORT(&up->port); + unsigned char r3; + bool push = false; + + 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) + push = ip22zilog_receive_chars(up, channel); + if (r3 & CHAEXT) + ip22zilog_status_handle(up, channel); + if (r3 & CHATxIP) + ip22zilog_transmit_chars(up, channel); + } + spin_unlock(&up->port.lock); + + if (push) + tty_flip_buffer_push(&up->port.state->port); + + /* Channel B */ + up = up->next; + channel = ZILOG_CHANNEL_FROM_PORT(&up->port); + push = false; + + spin_lock(&up->port.lock); + if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) { + writeb(RES_H_IUS, &channel->control); + ZSDELAY(); + ZS_WSYNC(channel); + + if (r3 & CHBRxIP) + push = ip22zilog_receive_chars(up, channel); + if (r3 & CHBEXT) + ip22zilog_status_handle(up, channel); + if (r3 & CHBTxIP) + ip22zilog_transmit_chars(up, channel); + } + spin_unlock(&up->port.lock); + + if (push) + tty_flip_buffer_push(&up->port.state->port); + + 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 = + container_of(port, 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 = + container_of(port, 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 = + container_of(port, 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->state->xmit; + + if (uart_circ_empty(xmit)) + return; + 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 = + container_of(port, 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 = + container_of(port, 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_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; +} + +static void __ip22zilog_startup(struct uart_ip22zilog_port *up) +{ + struct zilog_channel *channel; + + channel = ZILOG_CHANNEL_FROM_PORT(&up->port); + + __ip22zilog_reset(up); + + __load_zsregs(channel, up->curregs); + /* set master interrupt enable */ + write_zsreg(channel, R9, up->curregs[R9]); + 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 & (IGNBRK | 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 ktermios *termios, + struct ktermios *old) +{ + struct uart_ip22zilog_port *up = + container_of(port, 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; + + ip22zilog_maybe_update_regs(up, ZILOG_CHANNEL_FROM_PORT(port)); + uart_update_timeout(port, termios->c_cflag, baud); + + 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 const 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) +{ + return kzalloc(size, GFP_KERNEL); +} + +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 uart_port *port, int ch) +{ + struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port); + 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]; + unsigned long flags; + + spin_lock_irqsave(&up->port.lock, flags); + uart_console_write(&up->port, s, count, ip22zilog_put_char); + udelay(2); + spin_unlock_irqrestore(&up->port.lock, flags); +} + +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 = 9600, bits = 8; + int parity = 'n'; + int flow = 'n'; + + up->flags |= IP22ZILOG_FLAG_IS_CONS; + + printk(KERN_INFO "Console: ttyS%d (IP22-Zilog)\n", con->index); + + spin_lock_irqsave(&up->port.lock, flags); + + up->curregs[R15] |= BRKIE; + + __ip22zilog_startup(up); + + spin_unlock_irqrestore(&up->port.lock, flags); + + if (options) + uart_parse_options(options, &baud, &parity, &bits, &flow); + return uart_set_options(&up->port, con, baud, parity, bits, flow); +} + +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", + .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.line = (chip * 2) + 1; + up[(chip * 2) + 1].flags |= IP22ZILOG_FLAG_IS_CHANNEL_A; + } + + for (channel = 0; channel < NUM_CHANNELS; channel++) { + struct uart_ip22zilog_port *up = &ip22zilog_port_table[channel]; + int brg; + + /* 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; + brg = BPS_TO_BRG(9600, ZS_CLOCK / ZS_CLOCK_DIVISOR); + up->curregs[R12] = (brg & 0xff); + up->curregs[R13] = (brg >> 8) & 0xff; + up->curregs[R14] = BRENAB; + } +} + +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"); + } + + 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; + struct uart_ip22zilog_port *up; + + for (i = 0; i < NUM_CHANNELS; i++) { + up = &ip22zilog_port_table[i]; + + uart_remove_one_port(&ip22zilog_reg, &up->port); + } + + /* Free IO mem */ + up = &ip22zilog_port_table[0]; + for (i = 0; i < NUM_IP22ZILOG; i++) { + if (up[(i * 2) + 0].port.mapbase) { + iounmap((void*)up[(i * 2) + 0].port.mapbase); + up[(i * 2) + 0].port.mapbase = 0; + } + if (up[(i * 2) + 1].port.mapbase) { + iounmap((void*)up[(i * 2) + 1].port.mapbase); + up[(i * 2) + 1].port.mapbase = 0; + } + } + + 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"); |