serial.c

In the ffuart.tar.gz it has one file. The serial.c is the source codes of the FFUART as a console

/*
 *  linux/drivers/char/serial.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 
 * 		1998, 1999  Theodore Ts'o
 *
 *  Extensively rewritten by Theodore Ts'o, 8/16/92 -- 9/14/92.  Now
 *  much more extensible to support other serial cards based on the
 *  16450/16550A UART's.  Added support for the AST FourPort and the
 *  Accent Async board.  
 *
 *  set_serial_info fixed to set the flags, custom divisor, and uart
 * 	type fields.  Fix suggested by Michael K. Johnson 12/12/92.
 *
 *  11/95: TIOCMIWAIT, TIOCGICOUNT by Angelo Haritsis <[e-mail]>
 *
 *  03/96: Modularised by Angelo Haritsis <[e-mail]>
 *
 *  rs_set_termios fixed to look also for changes of the input
 *      flags INPCK, BRKINT, PARMRK, IGNPAR and IGNBRK.
 *                                            Bernd Anh鋟pl 05/17/96.
 *
 *  1/97:  Extended dumb serial ports are a config option now.  
 *         Saves 4k.   Michael A. Griffith <[e-mail]>
 * 
 *  8/97: Fix bug in rs_set_termios with RTS
 *        Stanislav V. Voronyi <[e-mail]>
 *
 *  3/98: Change the IRQ detection, use of probe_irq_o*(),
 *	  suppress TIOCSERGWILD and TIOCSERSWILD
 *	  Etienne Lorrain <[e-mail]>
 *
 *  4/98: Added changes to support the ARM architecture proposed by
 * 	  Russell King
 *
 *  5/99: Updated to include support for the XR16C850 and ST16C654
 *        uarts.  Stuart MacDonald <[e-mail]>
 *
 *  8/99: Generalized PCI support added.  Theodore Ts'o
 * 
 *  3/00: Rid circular buffer of redundant xmit_cnt.  Fix a
 *	  few races on freeing buffers too.
 *	  Alan Modra <[e-mail]>
 *
 *  5/00: Support for the RSA-DV II/S card added.
 *	  Kiyokazu SUTO <[e-mail]>
 * 
 *  6/00: Remove old-style timer, use timer_list
 *        Andrew Morton <[e-mail]>
 *
 *  7/00: Support Timedia/Sunix/Exsys PCI cards
 *
 *  7/00: fix some returns on failure not using MOD_DEC_USE_COUNT.
 *	  Arnaldo Carvalho de Melo <[e-mail]>
 *
 * 10/00: add in optional software flow control for serial console.
 *	  Kanoj Sarcar <[e-mail]>  (Modified by Theodore Ts'o)
 *
 */

static char *serial_version = "5.05c";
static char *serial_revdate = "2001-07-08";

/*
 * Serial driver configuration section.  Here are the various options:
 *
 * CONFIG_HUB6
 *		Enables support for the venerable Bell Technologies
 *		HUB6 card.
 *
 * CONFIG_SERIAL_MANY_PORTS
 * 		Enables support for ports beyond the standard, stupid
 * 		COM 1/2/3/4.
 *
 * CONFIG_SERIAL_MULTIPORT
 * 		Enables support for special multiport board support.
 *
 * CONFIG_SERIAL_SHARE_IRQ
 * 		Enables support for multiple serial ports on one IRQ
 *
 * CONFIG_SERIAL_DETECT_IRQ
 *		Enable the autodetection of IRQ on standart ports
 *
 * SERIAL_PARANOIA_CHECK
 * 		Check the magic number for the async_structure where
 * 		ever possible.
 *
 * CONFIG_SERIAL_ACPI
 *		Enable support for serial console port and serial 
 *		debug port as defined by the SPCR and DBGP tables in 
 *		ACPI 2.0.
 */

#include <linux/config.h>
#include <linux/version.h>

#undef SERIAL_PARANOIA_CHECK
#define CONFIG_SERIAL_NOPAUSE_IO
#define SERIAL_DO_RESTART

#if 0
/* These defines are normally controlled by the autoconf.h */
#define CONFIG_SERIAL_MANY_PORTS
#define CONFIG_SERIAL_SHARE_IRQ
#define CONFIG_SERIAL_DETECT_IRQ
#define CONFIG_SERIAL_MULTIPORT
#define CONFIG_HUB6
#endif

#ifdef CONFIG_PCI
#define ENABLE_SERIAL_PCI
#ifndef CONFIG_SERIAL_SHARE_IRQ
#define CONFIG_SERIAL_SHARE_IRQ
#endif
#ifndef CONFIG_SERIAL_MANY_PORTS
#define CONFIG_SERIAL_MANY_PORTS
#endif
#endif

#ifdef CONFIG_SERIAL_ACPI
#define ENABLE_SERIAL_ACPI
#endif

#if defined(CONFIG_ISAPNP)|| (defined(CONFIG_ISAPNP_MODULE) && defined(MODULE))
#ifndef ENABLE_SERIAL_PNP
#define ENABLE_SERIAL_PNP
#endif
#endif

#ifdef CONFIG_ARCH_PXA
#define pxa_port(x) ((x) == PORT_PXA)
#define pxa_buggy_port(x) ({ \
	int cpu_ver; asm("mrc%? p15, 0, %0, c0, c0" : "=r" (cpu_ver)); \
	((x) == PORT_PXA && (cpu_ver & ~1) == 0x69052100); })
#else
#define pxa_port(x) (0)
#define pxa_buggy_port(x) (0)
#endif

/* Set of debugging defines */

#undef SERIAL_DEBUG_INTR
#undef SERIAL_DEBUG_OPEN
#undef SERIAL_DEBUG_FLOW
#undef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
#undef SERIAL_DEBUG_PCI
#undef SERIAL_DEBUG_AUTOCONF

/* Sanity checks */

#ifdef CONFIG_SERIAL_MULTIPORT
#ifndef CONFIG_SERIAL_SHARE_IRQ
#define CONFIG_SERIAL_SHARE_IRQ
#endif
#endif

#ifdef CONFIG_HUB6
#ifndef CONFIG_SERIAL_MANY_PORTS
#define CONFIG_SERIAL_MANY_PORTS
#endif
#ifndef CONFIG_SERIAL_SHARE_IRQ
#define CONFIG_SERIAL_SHARE_IRQ
#endif
#endif

#ifdef MODULE
#undef CONFIG_SERIAL_CONSOLE
#endif

#define CONFIG_SERIAL_RSA

#define RS_STROBE_TIME (10*HZ)
#define RS_ISR_PASS_LIMIT 256

#if defined(__i386__) && (defined(CONFIG_M386) || defined(CONFIG_M486))
#define SERIAL_INLINE
#endif
  
/*
 * End of serial driver configuration section.
 */

#include <linux/module.h>

#include <linux/types.h>
#ifdef LOCAL_HEADERS
#include "serial_local.h"
#else
#include <linux/serial.h>
#include <linux/serialP.h>
#include <linux/serial_reg.h>
#include <asm/serial.h>
#define LOCAL_VERSTRING ""
#endif

#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/slab.h>
#if (LINUX_VERSION_CODE >= 131343)
#include <linux/init.h>
#endif
#if (LINUX_VERSION_CODE >= 131336)
#include <asm/uaccess.h>
#endif
#include <linux/delay.h>
#ifdef CONFIG_SERIAL_CONSOLE
#include <linux/console.h>
#endif
#ifdef ENABLE_SERIAL_PCI
#include <linux/pci.h>
#endif
#ifdef ENABLE_SERIAL_PNP
#include <linux/isapnp.h>
#endif
#ifdef CONFIG_MAGIC_SYSRQ
#include <linux/sysrq.h>
#endif

/*
 * All of the compatibilty code so we can compile serial.c against
 * older kernels is hidden in serial_compat.h
 */
#if defined(LOCAL_HEADERS) || (LINUX_VERSION_CODE < 0x020317) /* 2.3.23 */
#include "serial_compat.h"
#endif

#include <asm/system.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/bitops.h>

#if defined(CONFIG_MAC_SERIAL)
#define SERIAL_DEV_OFFSET	((_machine == _MACH_prep || _machine == _MACH_chrp) ? 0 : 2)
#else
#define SERIAL_DEV_OFFSET	0
#endif

#ifdef SERIAL_INLINE
#define _INLINE_ inline
#else
#define _INLINE_
#endif

static char *serial_name = "Serial driver";

static DECLARE_TASK_QUEUE(tq_serial);

static struct tty_driver serial_driver, callout_driver;
static int serial_refcount;

static struct timer_list serial_timer;

/* serial subtype definitions */
#ifndef SERIAL_TYPE_NORMAL
#define SERIAL_TYPE_NORMAL	1
#define SERIAL_TYPE_CALLOUT	2
#endif

/* number of characters left in xmit buffer before we ask for more */
#define WAKEUP_CHARS 256

/*
 * IRQ_timeout		- How long the timeout should be for each IRQ
 * 				should be after the IRQ has been active.
 */

static struct async_struct *IRQ_ports[NR_IRQS];
#ifdef CONFIG_SERIAL_MULTIPORT
static struct rs_multiport_struct rs_multiport[NR_IRQS];
#endif
static int IRQ_timeout[NR_IRQS];
#ifdef CONFIG_SERIAL_CONSOLE
static struct console sercons;
static int lsr_break_flag;
#endif
#if defined(CONFIG_SERIAL_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
static unsigned long break_pressed; /* break, really ... */
#endif

static unsigned detect_uart_irq (struct serial_state * state);
static void autoconfig(struct serial_state * state);
static void change_speed(struct async_struct *info, struct termios *old);
static void rs_wait_until_sent(struct tty_struct *tty, int timeout);

/*
 * Here we define the default xmit fifo size used for each type of
 * UART
 */
static struct serial_uart_config uart_config[] = {
	{ "unknown", 1, 0 }, 
	{ "8250", 1, 0 }, 
	{ "16450", 1, 0 }, 
	{ "16550", 1, 0 }, 
	{ "16550A", 16, UART_CLEAR_FIFO | UART_USE_FIFO }, 
	{ "cirrus", 1, 0 }, 	/* usurped by cyclades.c */
	{ "ST16650", 1, UART_CLEAR_FIFO | UART_STARTECH }, 
	{ "ST16650V2", 32, UART_CLEAR_FIFO | UART_USE_FIFO |
		  UART_STARTECH }, 
	{ "TI16750", 64, UART_CLEAR_FIFO | UART_USE_FIFO},
	{ "Startech", 1, 0},	/* usurped by cyclades.c */
	{ "16C950/954", 128, UART_CLEAR_FIFO | UART_USE_FIFO},
	{ "ST16654", 64, UART_CLEAR_FIFO | UART_USE_FIFO |
		  UART_STARTECH }, 
	{ "XR16850", 128, UART_CLEAR_FIFO | UART_USE_FIFO |
		  UART_STARTECH },
	{ "RSA", 2048, UART_CLEAR_FIFO | UART_USE_FIFO }, 
	{ "PXA UART", 32, UART_CLEAR_FIFO | UART_USE_FIFO },
	{ 0, 0}
};

#if defined(CONFIG_SERIAL_RSA) && defined(MODULE)

#define PORT_RSA_MAX 4
static int probe_rsa[PORT_RSA_MAX];
static int force_rsa[PORT_RSA_MAX];

MODULE_PARM(probe_rsa, "1-" __MODULE_STRING(PORT_RSA_MAX) "i");
MODULE_PARM_DESC(probe_rsa, "Probe I/O ports for RSA");
MODULE_PARM(force_rsa, "1-" __MODULE_STRING(PORT_RSA_MAX) "i");
MODULE_PARM_DESC(force_rsa, "Force I/O ports for RSA");
#endif /* CONFIG_SERIAL_RSA  */

static struct serial_state rs_table[RS_TABLE_SIZE] = {
	SERIAL_PORT_DFNS	/* Defined in serial.h */
};

#define NR_PORTS	(sizeof(rs_table)/sizeof(struct serial_state))

#if (defined(ENABLE_SERIAL_PCI) || defined(ENABLE_SERIAL_PNP))
#define NR_PCI_BOARDS	8

static struct pci_board_inst	serial_pci_board[NR_PCI_BOARDS];

#ifndef IS_PCI_REGION_IOPORT
#define IS_PCI_REGION_IOPORT(dev, r) (pci_resource_flags((dev), (r)) & \
				      IORESOURCE_IO)
#endif
#ifndef IS_PCI_REGION_IOMEM
#define IS_PCI_REGION_IOMEM(dev, r) (pci_resource_flags((dev), (r)) & \
				      IORESOURCE_MEM)
#endif
#ifndef PCI_IRQ_RESOURCE
#define PCI_IRQ_RESOURCE(dev, r) ((dev)->irq_resource[r].start)
#endif
#ifndef pci_get_subvendor
#define pci_get_subvendor(dev) ((dev)->subsystem_vendor)
#define pci_get_subdevice(dev)  ((dev)->subsystem_device)
#endif
#endif	/* ENABLE_SERIAL_PCI || ENABLE_SERIAL_PNP  */

#ifndef PREPARE_FUNC
#define PREPARE_FUNC(dev)  (dev->prepare)
#define ACTIVATE_FUNC(dev)  (dev->activate)
#define DEACTIVATE_FUNC(dev)  (dev->deactivate)
#endif

#define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8)

static struct tty_struct *serial_table[NR_PORTS];
static struct termios *serial_termios[NR_PORTS];
static struct termios *serial_termios_locked[NR_PORTS];


#if defined(MODULE) && defined(SERIAL_DEBUG_MCOUNT)
#define DBG_CNT(s) printk("(%s): [%x] refc=%d, serc=%d, ttyc=%d -> %s\n", \
 kdevname(tty->device), (info->flags), serial_refcount,info->count,tty->count,s)
#else
#define DBG_CNT(s)
#endif

/*
 * tmp_buf is used as a temporary buffer by serial_write.  We need to
 * lock it in case the copy_from_user blocks while swapping in a page,
 * and some other program tries to do a serial write at the same time.
 * Since the lock will only come under contention when the system is
 * swapping and available memory is low, it makes sense to share one
 * buffer across all the serial ports, since it significantly saves
 * memory if large numbers of serial ports are open.
 */
static unsigned char *tmp_buf;
#ifdef DECLARE_MUTEX
static DECLARE_MUTEX(tmp_buf_sem);
#else
static struct semaphore tmp_buf_sem = MUTEX;
#endif


static inline int serial_paranoia_check(struct async_struct *info,
					kdev_t device, const char *routine)
{
#ifdef SERIAL_PARANOIA_CHECK
	static const char *badmagic =
		"Warning: bad magic number for serial struct (%s) in %s\n";
	static const char *badinfo =
		"Warning: null async_struct for (%s) in %s\n";

	if (!info) {
		printk(badinfo, kdevname(device), routine);
		return 1;
	}
	if (info->magic != SERIAL_MAGIC) {
		printk(badmagic, kdevname(device), routine);
		return 1;
	}
#endif
	return 0;
}

static _INLINE_ unsigned int serial_in(struct async_struct *info, int offset)
{
	switch (info->io_type) {
#ifdef CONFIG_HUB6
	case SERIAL_IO_HUB6:
		outb(info->hub6 - 1 + offset, info->port);
		return inb(info->port+1);
#endif
	case SERIAL_IO_MEM:
		return readb((unsigned long) info->iomem_base +
			     (offset<<info->iomem_reg_shift));
	case SERIAL_IO_MEM32:
		return readl((unsigned long) info->iomem_base +
				(offset<<info->iomem_reg_shift));
#ifdef CONFIG_SERIAL_GSC
	case SERIAL_IO_GSC:
		return gsc_readb(info->iomem_base + offset);
#endif
	default:
		return inb(info->port + offset);
	}
}

static _INLINE_ void serial_out(struct async_struct *info, int offset,
				int value)
{
	switch (info->io_type) {
#ifdef CONFIG_HUB6
	case SERIAL_IO_HUB6:
		outb(info->hub6 - 1 + offset, info->port);
		outb(value, info->port+1);
		break;
#endif
	case SERIAL_IO_MEM:
		writeb(value, (unsigned long) info->iomem_base +
			      (offset<<info->iomem_reg_shift));
		break;
	case SERIAL_IO_MEM32:
		writel(value, (unsigned long) info->iomem_base +
				(offset<<info->iomem_reg_shift));
		break;
#ifdef CONFIG_SERIAL_GSC
	case SERIAL_IO_GSC:
		gsc_writeb(value, info->iomem_base + offset);
		break;
#endif
	default:
		outb(value, info->port+offset);
	}
}

/*
 * We used to support using pause I/O for certain machines.  We
 * haven't supported this for a while, but just in case it's badly
 * needed for certain old 386 machines, I've left these #define's
 * in....
 */
#define serial_inp(info, offset)		serial_in(info, offset)
#define serial_outp(info, offset, value)	serial_out(info, offset, value)


/*
 * For the 16C950
 */
void serial_icr_write(struct async_struct *info, int offset, int  value)
{
	serial_out(info, UART_SCR, offset);
	serial_out(info, UART_ICR, value);
}

unsigned int serial_icr_read(struct async_struct *info, int offset)
{
	int	value;