path: root/drivers/serial/zs.c

/*
 * 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