path: root/drivers/serial/sunsab.c

/* sunsab.c: ASYNC Driver for the SIEMENS SAB82532 DUSCC.
 *
 * Copyright (C) 1997  Eddie C. Dost  (ecd@skynet.be)
 * Copyright (C) 2002, 2006  David S. Miller (davem@davemloft.net)
 *
 * Rewrote buffer handling to use CIRC(Circular Buffer) macros.
 *   Maxim Krasnyanskiy <maxk@qualcomm.com>
 *
 * Fixed to use tty_get_baud_rate, and to allow for arbitrary baud
 * rates to be programmed into the UART.  Also eliminated a lot of
 * duplicated code in the console setup.
 *   Theodore Ts'o <tytso@mit.edu>, 2001-Oct-12
 *
 * Ported to new 2.5.x UART layer.
 *   David S. Miller <davem@davemloft.net>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.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/circ_buf.h>
#include <linux/serial.h>
#include <linux/sysrq.h>
#include <linux/console.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/init.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/prom.h>
#include <asm/of_device.h>

#if defined(CONFIG_SERIAL_SUNSAB_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/serial_core.h>

#include "suncore.h"
#include "sunsab.h"

struct uart_sunsab_port {
	struct uart_port		port;		/* Generic UART port	*/
	union sab82532_async_regs	__iomem *regs;	/* Chip registers	*/
	unsigned long			irqflags;	/* IRQ state flags	*/
	int				dsr;		/* Current DSR state	*/
	unsigned int			cec_timeout;	/* Chip poll timeout... */
	unsigned int			tec_timeout;	/* likewise		*/
	unsigned char			interrupt_mask0;/* ISR0 masking		*/
	unsigned char			interrupt_mask1;/* ISR1 masking		*/
	unsigned char			pvr_dtr_bit;	/* Which PVR bit is DTR */
	unsigned char			pvr_dsr_bit;	/* Which PVR bit is DSR */
	unsigned int			gis_shift;
	int				type;		/* SAB82532 version	*/

	/* Setting configuration bits while the transmitter is active
	 * can cause garbage characters to get emitted by the chip.
	 * Therefore, we cache such writes here and do the real register
	 * write the next time the transmitter becomes idle.
	 */
	unsigned int			cached_ebrg;
	unsigned char			cached_mode;
	unsigned char			cached_pvr;
	unsigned char			cached_dafo;
};

/*
 * This assumes you have a 29.4912 MHz clock for your UART.
 */
#define SAB_BASE_BAUD ( 29491200 / 16 )

static char *sab82532_version[16] = {
	"V1.0", "V2.0", "V3.2", "V(0x03)",
	"V(0x04)", "V(0x05)", "V(0x06)", "V(0x07)",
	"V(0x08)", "V(0x09)", "V(0x0a)", "V(0x0b)",
	"V(0x0c)", "V(0x0d)", "V(0x0e)", "V(0x0f)"
};

#define SAB82532_MAX_TEC_TIMEOUT 200000	/* 1 character time (at 50 baud) */
#define SAB82532_MAX_CEC_TIMEOUT  50000	/* 2.5 TX CLKs (at 50 baud) */

#define SAB82532_RECV_FIFO_SIZE	32      /* Standard async fifo sizes */
#define SAB82532_XMIT_FIFO_SIZE	32

static __inline__ void sunsab_tec_wait(struct uart_sunsab_port *up)
{
	int timeout = up->tec_timeout;

	while ((readb(&up->regs->r.star) & SAB82532_STAR_TEC) && --timeout)
		udelay(1);
}

static __inline__ void sunsab_cec_wait(struct uart_sunsab_port *up)
{
	int timeout = up->cec_timeout;

	while ((readb(&up->regs->r.star) & SAB82532_STAR_CEC) && --timeout)
		udelay(1);
}

static struct tty_struct *
receive_chars(struct uart_sunsab_port *up,
	      union sab82532_irq_status *stat)
{
	struct tty_struct *tty = NULL;
	unsigned char buf[32];
	int saw_console_brk = 0;
	int free_fifo = 0;
	int count = 0;
	int i;

	if (up->port.info != NULL)		/* Unopened serial console */
		tty = up->port.info->tty;

	/* Read number of BYTES (Character + Status) available. */
	if (stat->sreg.isr0 & SAB82532_ISR0_RPF) {
		count = SAB82532_RECV_FIFO_SIZE;
		free_fifo++;
	}

	if (stat->sreg.isr0 & SAB82532_ISR0_TCD) {
		count