vme_scc.c

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/*
 * drivers/char/vme_scc.c: MVME147, MVME162, BVME6000 SCC serial ports
 * implementation.
 * Copyright 1999 Richard Hirst <[e-mail]>
 *
 * Based on atari_SCC.c which was
 *   Copyright 1994-95 Roman Hodek <[e-mail]>
 *   Partially based on PC-Linux serial.c by Linus Torvalds and Theodore Ts'o
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 *
 */

#include <linux/module.h>
#include <linux/config.h>
#include <linux/kdev_t.h>
#include <asm/io.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/mm.h>
#include <linux/serial.h>
#include <linux/fcntl.h>
#include <linux/major.h>
#include <linux/delay.h>
#include <linux/tqueue.h>
#include <linux/version.h>
#include <linux/malloc.h>
#include <linux/miscdevice.h>
#include <linux/console.h>
#include <linux/init.h>
#include <asm/setup.h>
#include <asm/bootinfo.h>

#ifdef CONFIG_MVME147_SCC
#include <asm/mvme147hw.h>
#endif
#ifdef CONFIG_MVME162_SCC
#include <asm/mvme16xhw.h>
#endif
#ifdef CONFIG_BVME6000_SCC
#include <asm/bvme6000hw.h>
#endif

#include <linux/generic_serial.h>
#include "scc.h"


#define CHANNEL_A	0
#define CHANNEL_B	1

#define SCC_MINOR_BASE	64

/* Shadows for all SCC write registers */
static unsigned char scc_shadow[2][16];

/* Location to access for SCC register access delay */
static volatile unsigned char *scc_del = NULL;

/* To keep track of STATUS_REG state for detection of Ext/Status int source */
static unsigned char scc_last_status_reg[2];

/***************************** Prototypes *****************************/

/* Function prototypes */
static void scc_disable_tx_interrupts(void * ptr);
static void scc_enable_tx_interrupts(void * ptr);
static void scc_disable_rx_interrupts(void * ptr);
static void scc_enable_rx_interrupts(void * ptr);
static int  scc_get_CD(void * ptr);
static void scc_shutdown_port(void * ptr);
static int scc_set_real_termios(void  *ptr);
static void scc_hungup(void  *ptr);
static void scc_close(void  *ptr);
static int scc_chars_in_buffer(void * ptr);
static int scc_open(struct tty_struct * tty, struct file * filp);
static int scc_ioctl(struct tty_struct * tty, struct file * filp,
                     unsigned int cmd, unsigned long arg);
static void scc_throttle(struct tty_struct *tty);
static void scc_unthrottle(struct tty_struct *tty);
static void scc_tx_int(int irq, void *data, struct pt_regs *fp);
static void scc_rx_int(int irq, void *data, struct pt_regs *fp);
static void scc_stat_int(int irq, void *data, struct pt_regs *fp);
static void scc_spcond_int(int irq, void *data, struct pt_regs *fp);
static void scc_setsignals(struct scc_port *port, int dtr, int rts);
static void scc_break_ctl(struct tty_struct *tty, int break_state);

static struct tty_driver scc_driver, scc_callout_driver;

static struct tty_struct *scc_table[2] = { NULL, };
static struct termios * scc_termios[2];
static struct termios * scc_termios_locked[2];
struct scc_port scc_ports[2];

int scc_refcount;
int scc_initialized = 0;

/*---------------------------------------------------------------------------
 * Interface from generic_serial.c back here
 *--------------------------------------------------------------------------*/

static struct real_driver scc_real_driver = {
        scc_disable_tx_interrupts,
        scc_enable_tx_interrupts,
        scc_disable_rx_interrupts,
        scc_enable_rx_interrupts,
        scc_get_CD,
        scc_shutdown_port,
        scc_set_real_termios,
        scc_chars_in_buffer,
        scc_close,
        scc_hungup,
        NULL
};


/*----------------------------------------------------------------------------
 * vme_scc_init() and support functions
 *---------------------------------------------------------------------------*/

static int scc_init_drivers(void)
{
	int error;

	memset(&scc_driver, 0, sizeof(scc_driver));
	scc_driver.magic = TTY_DRIVER_MAGIC;
	scc_driver.driver_name = "scc";
	scc_driver.name = "ttyS";
	scc_driver.major = TTY_MAJOR;
	scc_driver.minor_start = SCC_MINOR_BASE;
	scc_driver.num = 2;
	scc_driver.type = TTY_DRIVER_TYPE_SERIAL;
	scc_driver.subtype = SERIAL_TYPE_NORMAL;
	scc_driver.init_termios = tty_std_termios;
	scc_driver.init_termios.c_cflag =
	  B9600 | CS8 | CREAD | HUPCL | CLOCAL;
	scc_driver.flags = TTY_DRIVER_REAL_RAW;
	scc_driver.refcount = &scc_refcount;
	scc_driver.table = scc_table;
	scc_driver.termios = scc_termios;
	scc_driver.termios_locked = scc_termios_locked;

	scc_driver.open	= scc_open;
	scc_driver.close = gs_close;
	scc_driver.write = gs_write;
	scc_driver.put_char = gs_put_char;
	scc_driver.flush_chars = gs_flush_chars;
	scc_driver.write_room = gs_write_room;
	scc_driver.chars_in_buffer = gs_chars_in_buffer;
	scc_driver.flush_buffer = gs_flush_buffer;
	scc_driver.ioctl = scc_ioctl;
	scc_driver.throttle = scc_throttle;
	scc_driver.unthrottle = scc_unthrottle;
	scc_driver.set_termios = gs_set_termios;
	scc_driver.stop = gs_stop;
	scc_driver.start = gs_start;
	scc_driver.hangup = gs_hangup;
	scc_driver.break_ctl = scc_break_ctl;

	scc_callout_driver = scc_driver;
	scc_callout_driver.name = "cua";
	scc_callout_driver.major = TTYAUX_MAJOR;
	scc_callout_driver.subtype = SERIAL_TYPE_CALLOUT;

	if ((error = tty_register_driver(&scc_driver))) {
		printk(KERN_ERR "scc: Couldn't register scc driver, error = %d\n",
		       error);
		return 1;
	}
	if ((error = tty_register_driver(&scc_callout_driver))) {
		tty_unregister_driver(&scc_driver);
		printk(KERN_ERR "scc: Couldn't register scc callout driver, error = %d\n",
		       error);
		return 1;
	}

	return 0;
}


/* ports[] array is indexed by line no (i.e. [0] for ttyS0, [1] for ttyS1).
 */

static void scc_init_portstructs(void)
{
	struct scc_port *port;
	int i;

	for (i = 0; i < 2; i++) {
		port = scc_ports + i;
		port->gs.callout_termios = tty_std_termios;
		port->gs.normal_termios = tty_std_termios;
		port->gs.magic = SCC_MAGIC;
		port->gs.close_delay = HZ/2;
		port->gs.closing_wait = 30 * HZ;
		port->gs.rd = &scc_real_driver;
#ifdef NEW_WRITE_LOCKING
		port->gs.port_write_sem = MUTEX;
#endif
		init_waitqueue_head(&port->gs.open_wait);
		init_waitqueue_head(&port->gs.close_wait);
	}
}


#ifdef CONFIG_MVME147_SCC
static int mvme147_scc_init(void)
{
	struct scc_port *port;

	printk("SCC: MVME147 Serial Driver\n");
	/* Init channel A */
	port = &scc_ports[0];
	port->channel = CHANNEL_A;
	port->ctrlp = (volatile unsigned char *)M147_SCC_A_ADDR;
	port->datap = port->ctrlp + 1;
	port->port_a = &scc_ports[0];
	port->port_b = &scc_ports[1];
	request_irq(MVME147_IRQ_SCCA_TX, scc_tx_int, SA_INTERRUPT,
		            "SCC-A TX", port);
	request_irq(MVME147_IRQ_SCCA_STAT, scc_stat_int, SA_INTERRUPT,
		            "SCC-A status", port);
	request_irq(MVME147_IRQ_SCCA_RX, scc_rx_int, SA_INTERRUPT,
		            "SCC-A RX", port);
	request_irq(MVME147_IRQ_SCCA_SPCOND, scc_spcond_int, SA_INTERRUPT,
		            "SCC-A special cond", port);
	{
		SCC_ACCESS_INIT(port);

		/* disable interrupts for this channel */
		SCCwrite(INT_AND_DMA_REG, 0);
		/* Set the interrupt vector */
		SCCwrite(INT_VECTOR_REG, MVME147_IRQ_SCC_BASE);
		/* Interrupt parameters: vector includes status, status low */
		SCCwrite(MASTER_INT_CTRL, MIC_VEC_INCL_STAT);
		SCCmod(MASTER_INT_CTRL, 0xff, MIC_MASTER_INT_ENAB);
	}

	/* Init channel B */
	port = &scc_ports[1];
	port->channel = CHANNEL_B;
	port->ctrlp = (volatile unsigned char *)M147_SCC_B_ADDR;
	port->datap = port->ctrlp + 1;
	port->port_a = &scc_ports[0];
	port->port_b = &scc_ports[1];
	request_irq(MVME147_IRQ_SCCB_TX, scc_tx_int, SA_INTERRUPT,
		            "SCC-B TX", port);
	request_irq(MVME147_IRQ_SCCB_STAT, scc_stat_int, SA_INTERRUPT,
		            "SCC-B status", port);
	request_irq(MVME147_IRQ_SCCB_RX, scc_rx_int, SA_INTERRUPT,
		            "SCC-B RX", port);
	request_irq(MVME147_IRQ_SCCB_SPCOND, scc_spcond_int, SA_INTERRUPT,
		            "SCC-B special cond", port);
	{
		SCC_ACCESS_INIT(port);

		/* disable interrupts for this channel */
		SCCwrite(INT_AND_DMA_REG, 0);
	}

        /* Ensure interrupts are enabled in the PCC chip */
        m147_pcc->serial_cntrl=PCC_LEVEL_SERIAL|PCC_INT_ENAB;

	/* Initialise the tty driver structures and register */
	scc_init_portstructs();
	scc_init_drivers();

	return 0;
}
#endif


#ifdef CONFIG_MVME162_SCC
static int mvme162_scc_init(void)
{
	struct scc_port *port;

	if (!(mvme16x_config & MVME16x_CONFIG_GOT_SCCA))
		return (-ENODEV);

	printk("SCC: MVME162 Serial Driver\n");
	/* Init channel A */
	port = &scc_ports[0];
	port->channel = CHANNEL_A;
	port->ctrlp = (volatile unsigned char *)MVME_SCC_A_ADDR;
	port->datap = port->ctrlp + 2;
	port->port_a = &scc_ports[0];
	port->port_b = &scc_ports[1];
	request_irq(MVME162_IRQ_SCCA_TX, scc_tx_int, SA_INTERRUPT,
		            "SCC-A TX", port);
	request_irq(MVME162_IRQ_SCCA_STAT, scc_stat_int, SA_INTERRUPT,
		            "SCC-A status", port);
	request_irq(MVME162_IRQ_SCCA_RX, scc_rx_int, SA_INTERRUPT,
		            "SCC-A RX", port);
	request_irq(MVME162_IRQ_SCCA_SPCOND, scc_spcond_int, SA_INTERRUPT,
		            "SCC-A special cond", port);
	{
		SCC_ACCESS_INIT(port);

		/* disable interrupts for this channel */
		SCCwrite(INT_AND_DMA_REG, 0);
		/* Set the interrupt vector */
		SCCwrite(INT_VECTOR_REG, MVME162_IRQ_SCC_BASE);
		/* Interrupt parameters: vector includes status, status low */
		SCCwrite(MASTER_INT_CTRL, MIC_VEC_INCL_STAT);
		SCCmod(MASTER_INT_CTRL, 0xff, MIC_MASTER_INT_ENAB);
	}

	/* Init channel B */
	port = &scc_ports[1];
	port->channel = CHANNEL_B;
	port->ctrlp = (volatile unsigned char *)MVME_SCC_B_ADDR;
	port->datap = port->ctrlp + 2;
	port->port_a = &scc_ports[0];
	port->port_b = &scc_ports[1];
	request_irq(MVME162_IRQ_SCCB_TX, scc_tx_int, SA_INTERRUPT,
		            "SCC-B TX", port);
	request_irq(MVME162_IRQ_SCCB_STAT, scc_stat_int, SA_INTERRUPT,
		            "SCC-B status", port);
	request_irq(MVME162_IRQ_SCCB_RX, scc_rx_int, SA_INTERRUPT,
		            "SCC-B RX", port);
	request_irq(MVME162_IRQ_SCCB_SPCOND, scc_spcond_int, SA_INTERRUPT,
		            "SCC-B special cond", port);

	{
		SCC_ACCESS_INIT(port);	/* Either channel will do */

		/* disable interrupts for this channel */
		SCCwrite(INT_AND_DMA_REG, 0);
	}

        /* Ensure interrupts are enabled in the MC2 chip */
        *(volatile char *)0xfff4201d = 0x14;

	/* Initialise the tty driver structures and register */
	scc_init_portstructs();
	scc_init_drivers();

	return 0;
}
#endif


#ifdef CONFIG_BVME6000_SCC
static int bvme6000_scc_init(void)
{
	struct scc_port *port;

	printk("SCC: BVME6000 Serial Driver\n");
	/* Init channel A */
	port = &scc_ports[0];
	port->channel = CHANNEL_A;
	port->ctrlp = (volatile unsigned char *)BVME_SCC_A_ADDR;
	port->datap = port->ctrlp + 4;
	port->port_a = &scc_ports[0];
	port->port_b = &scc_ports[1];
	request_irq(BVME_IRQ_SCCA_TX, scc_tx_int, SA_INTERRUPT,
		            "SCC-A TX", port);
	request_irq(BVME_IRQ_SCCA_STAT, scc_stat_int, SA_INTERRUPT,
		            "SCC-A status", port);
	request_irq(BVME_IRQ_SCCA_RX, scc_rx_int, SA_INTERRUPT,
		            "SCC-A RX", port);
	request_irq(BVME_IRQ_SCCA_SPCOND, scc_spcond_int, SA_INTERRUPT,
		            "SCC-A special cond", port);
	{
		SCC_ACCESS_INIT(port);

		/* disable interrupts for this channel */
		SCCwrite(INT_AND_DMA_REG, 0);
		/* Set the interrupt vector */
		SCCwrite(INT_VECTOR_REG, BVME_IRQ_SCC_BASE);
		/* Interrupt parameters: vector includes status, status low */
		SCCwrite(MASTER_INT_CTRL, MIC_VEC_INCL_STAT);
		SCCmod(MASTER_INT_CTRL, 0xff, MIC_MASTER_INT_ENAB);
	}

	/* Init channel B */
	port = &scc_ports[1];
	port->channel = CHANNEL_B;
	port->ctrlp = (volatile unsigned char *)BVME_SCC_B_ADDR;
	port->datap = port->ctrlp + 4;
	port->port_a = &scc_ports[0];
	port->port_b = &scc_ports[1];
	request_irq(BVME_IRQ_SCCB_TX, scc_tx_int, SA_INTERRUPT,
		            "SCC-B TX", port);
	request_irq(BVME_IRQ_SCCB_STAT, scc_stat_int, SA_INTERRUPT,
		            "SCC-B status", port);
	request_irq(BVME_IRQ_SCCB_RX, scc_rx_int, SA_INTERRUPT,
		            "SCC-B RX", port);
	request_irq(BVME_IRQ_SCCB_SPCOND, scc_spcond_int, SA_INTERRUPT,
		            "SCC-B special cond", port);

	{
		SCC_ACCESS_INIT(port);	/* Either channel will do */

		/* disable interrupts for this channel */
		SCCwrite(INT_AND_DMA_REG, 0);
	}

	/* Initialise the tty driver structures and register */
	scc_init_portstructs();
	scc_init_drivers();

	return 0;
}
#endif


int vme_scc_init(void)
{
	int res = -ENODEV;
	static int called = 0;

	if (called)
		return res;
	called = 1;
#ifdef CONFIG_MVME147_SCC
	if (MACH_IS_MVME147)
		res = mvme147_scc_init();
#endif
#ifdef CONFIG_MVME162_SCC
	if (MACH_IS_MVME16x)
		res = mvme162_scc_init();
#endif
#ifdef CONFIG_BVME6000_SCC
	if (MACH_IS_BVME6000)
		res = bvme6000_scc_init();
#endif
	return res;
}


/*---------------------------------------------------------------------------
 * Interrupt handlers
 *--------------------------------------------------------------------------*/

static void scc_rx_int(int irq, void *data, struct pt_regs *fp)
{
	unsigned char	ch;
	struct scc_port *port = data;
	struct tty_struct *tty = port->gs.tty;
	SCC_ACCESS_INIT(port);

	ch = SCCread_NB(RX_DATA_REG);
	if (!tty) {
		printk ("scc_rx_int with NULL tty!\n");
		SCCwrite_NB(COMMAND_REG, CR_HIGHEST_IUS_RESET);
		return;
	}
	if (tty->flip.count < TTY_FLIPBUF_SIZE) {
		*tty->flip.char_buf_ptr = ch;
		*tty->flip.flag_buf_ptr = 0;
		tty->flip.flag_buf_ptr++;
		tty->flip.char_buf_ptr++;
		tty->flip.count++;
	}

	/* Check if another character is already ready; in that case, the
	 * spcond_int() function must be used, because this character may have an
	 * error condition that isn't signalled by the interrupt vector used!
	 */
	if (SCCread(INT_PENDING_REG) &
	    (port->channel == CHANNEL_A ? IPR_A_RX : IPR_B_RX)) {
		scc_spcond_int (irq, data, fp);
		return;
	}

	SCCwrite_NB(COMMAND_REG, CR_HIGHEST_IUS_RESET);

	tty_flip_buffer_push(tty);
}


static void scc_spcond_int(int irq, void *data, struct pt_regs *fp)
{
	struct scc_port *port = data;
	struct tty_struct *tty = port->gs.tty;
	unsigned char	stat, ch, err;
	int		int_pending_mask = port->channel == CHANNEL_A ?
			                   IPR_A_RX : IPR_B_RX;
	SCC_ACCESS_INIT(port);
	
	if (!tty) {
		printk ("scc_spcond_int with NULL tty!\n");
		SCCwrite(COMMAND_REG, CR_ERROR_RESET);
		SCCwrite_NB(COMMAND_REG, CR_HIGHEST_IUS_RESET);
		return;
	}
	do {
		stat = SCCread(SPCOND_STATUS_REG);
		ch = SCCread_NB(RX_DATA_REG);

		if (stat & SCSR_RX_OVERRUN)
			err = TTY_OVERRUN;
		else if (stat & SCSR_PARITY_ERR)
			err = TTY_PARITY;
		else if (stat & SCSR_CRC_FRAME_ERR)
			err = TTY_FRAME;
		else
			err = 0;

		if (tty->flip.count < TTY_FLIPBUF_SIZE) {
			*tty->flip.char_buf_ptr = ch;
			*tty->flip.flag_buf_ptr = err;
			tty->flip.flag_buf_ptr++;
			tty->flip.char_buf_ptr++;
			tty->flip.count++;
		}

		/* ++TeSche: *All* errors have to be cleared manually,
		 * else the condition persists for the next chars
		 */
		if (err)
		  SCCwrite(COMMAND_REG, CR_ERROR_RESET);

	} while(SCCread(INT_PENDING_REG) & int_pending_mask);

	SCCwrite_NB(COMMAND_REG, CR_HIGHEST_IUS_RESET);

	tty_flip_buffer_push(tty);
}


static void scc_tx_int(int irq, void *data, struct pt_regs *fp)
{
	struct scc_port *port = data;
	SCC_ACCESS_INIT(port);

	if (!port->gs.tty) {
		printk ("scc_tx_int with NULL tty!\n");
		SCCmod (INT_AND_DMA_REG, ~IDR_TX_INT_ENAB, 0);
		SCCwrite(COMMAND_REG, CR_TX_PENDING_RESET);
		SCCwrite_NB(COMMAND_REG, CR_HIGHEST_IUS_RESET);
		return;
	}
	while ((SCCread_NB(STATUS_REG) & SR_TX_BUF_EMPTY)) {
		if (port->x_char) {
			SCCwrite(TX_DATA_REG, port->x_char);
			port->x_char = 0;
		}
		else if ((port->gs.xmit_cnt <= 0) || port->gs.tty->stopped ||
				port->gs.tty->hw_stopped)
			break;
		else {
			SCCwrite(TX_DATA_REG, port->gs.xmit_buf[port->gs.xmit_tail++]);
			port->gs.xmit_tail = port->gs.xmit_tail & (SERIAL_XMIT_SIZE-1);
			if (--port->gs.xmit_cnt <= 0)
				break;
		}
	}
	if ((port->gs.xmit_cnt <= 0) || port->gs.tty->stopped ||
			port->gs.tty->hw_stopped) {
		/* disable tx interrupts */
		SCCmod (INT_AND_DMA_REG, ~IDR_TX_INT_ENAB, 0);
		SCCwrite(COMMAND_REG, CR_TX_PENDING_RESET);   /* disable tx_int on next tx underrun? */
		port->gs.flags &= ~GS_TX_INTEN;
	}
	if (port->gs.tty && port->gs.xmit_cnt <= port->gs.wakeup_chars) {
		if ((port->gs.tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
				port->gs.tty->ldisc.write_wakeup)
			(port->gs.tty->ldisc.write_wakeup)(port->gs.tty);
		wake_up_interruptible(&port->gs.tty->write_wait);