patch-2.4.21 linux-2.4.21/arch/alpha/kernel/srmcons.c

• Lines: 362
• Date: 2003-06-13 07:51:29.000000000 -0700
• Orig file: linux-2.4.20/arch/alpha/kernel/srmcons.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.20/arch/alpha/kernel/srmcons.c linux-2.4.21/arch/alpha/kernel/srmcons.c
@@ -0,0 +1,361 @@
+/*
+ *	linux/arch/alpha/kernel/srmcons.c
+ *
+ * Callback based driver for SRM Console console device.
+ * (TTY driver and console driver)
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+
+#include <asm/console.h>
+#include <asm/uaccess.h>
+
+
+static spinlock_t srmcons_callback_lock = SPIN_LOCK_UNLOCKED;
+static int srm_is_registered_console = 0;
+
+/* 
+ * The TTY driver
+ */
+#define MAX_SRM_CONSOLE_DEVICES 1	/* only support 1 console device */
+
+static int srmcons_refcount;
+static struct tty_struct *srmcons_table[MAX_SRM_CONSOLE_DEVICES];
+static struct termios *srmcons_termios[MAX_SRM_CONSOLE_DEVICES];
+static struct termios *srmcons_termios_locked[MAX_SRM_CONSOLE_DEVICES];
+
+struct srmcons_private {
+	struct tty_struct *tty;
+	struct timer_list timer;
+	spinlock_t lock;
+};
+
+typedef union _srmcons_result {
+	struct {
+		unsigned long c :61;
+		unsigned long status :3;
+	} bits;
+	long as_long;
+} srmcons_result;
+
+/* called with callback_lock held */
+static int
+srmcons_do_receive_chars(struct tty_struct *tty)
+{
+	srmcons_result result;
+	int count = 0, loops = 0;
+
+	do {
+		result.as_long = callback_getc(0);
+		if (result.bits.status < 2) {
+			tty_insert_flip_char(tty, (char)result.bits.c, 0);
+			count++;
+		}
+	} while((result.bits.status & 1) && (++loops < 10));
+
+	if (count)
+		tty_schedule_flip(tty);
+
+	return count;
+}
+
+static void
+srmcons_receive_chars(unsigned long data)
+{
+	struct srmcons_private *srmconsp = (struct srmcons_private *)data;
+	unsigned long flags;
+	int incr = 10;
+
+	local_irq_save(flags);
+	if (spin_trylock(&srmcons_callback_lock)) {
+		if (!srmcons_do_receive_chars(srmconsp->tty))
+			incr = 100;
+		spin_unlock(&srmcons_callback_lock);
+	} 
+
+	spin_lock(&srmconsp->lock);
+	if (srmconsp->tty) {
+		srmconsp->timer.expires = jiffies + incr;
+		add_timer(&srmconsp->timer);
+	}
+	spin_unlock(&srmconsp->lock);
+
+	local_irq_restore(flags);
+}
+
+/* called with callback_lock held */
+static int
+srmcons_do_write(struct tty_struct *tty, const unsigned char *buf, int count)
+{
+	unsigned char *str_cr = "\r";
+	long c, remaining = count;
+	srmcons_result result;
+	unsigned char *cur;
+	int need_cr;
+
+	for (cur = (unsigned char *)buf; remaining > 0; ) {
+		need_cr = 0;
+		/* 
+		 * Break it up into reasonable size chunks to allow a chance
+		 * for input to get in
+		 */
+		for (c = 0; c < min_t(long, 128L, remaining) && !need_cr; c++)
+			if (cur[c] == '\n')
+				need_cr = 1;
+		
+		while (c > 0) {
+			result.as_long = callback_puts(0, cur, c);
+			c -= result.bits.c;
+			remaining -= result.bits.c;
+			cur += result.bits.c;
+
+			/*
+			 * Check for pending input iff a tty was provided
+			 */
+			if (tty)
+				srmcons_do_receive_chars(tty);
+		}
+
+		while (need_cr) {
+			result.as_long = callback_puts(0, str_cr, 1);
+			if (result.bits.c > 0)
+				need_cr = 0;
+		}
+	}
+	return count;
+}
+
+static int
+srmcons_write(struct tty_struct *tty, int from_user,
+	      const unsigned char *buf, int count)
+{
+	unsigned long flags;
+
+	if (from_user) {
+		unsigned char tmp[512];
+		int ret = 0;
+		size_t c;
+
+		while ((c = count) > 0) {
+			if (c > sizeof(tmp))
+				c = sizeof(tmp);
+			
+			c -= copy_from_user(tmp, buf, c);
+
+			if (!c) { 
+				printk("%s: EFAULT (count %d)\n",
+				       __FUNCTION__, count);
+				return -EFAULT;
+			}
+
+			spin_lock_irqsave(&srmcons_callback_lock, flags);
+			srmcons_do_write(tty, tmp, c);
+			spin_unlock_irqrestore(&srmcons_callback_lock, flags);
+
+			buf += c;
+			count -= c;
+			ret += c;
+		}
+
+		return ret;
+	}
+
+	spin_lock_irqsave(&srmcons_callback_lock, flags);
+	srmcons_do_write(tty, buf, count);
+	spin_unlock_irqrestore(&srmcons_callback_lock, flags);
+
+	return count;
+}
+
+static int
+srmcons_write_room(struct tty_struct *tty)
+{
+	return 512;
+}
+
+static int
+srmcons_chars_in_buffer(struct tty_struct *tty)
+{
+	return 0;
+}
+
+static int
+srmcons_get_private_struct(struct srmcons_private **ps)
+{
+	static struct srmcons_private *srmconsp = NULL;
+	static spinlock_t srmconsp_lock = SPIN_LOCK_UNLOCKED;
+	unsigned long flags;
+	int retval = 0;
+
+	spin_lock_irqsave(&srmconsp_lock, flags);
+
+	do {
+		if (srmconsp != NULL) {
+			*ps = srmconsp;
+			break;
+		}
+
+		srmconsp = kmalloc(sizeof(*srmconsp), GFP_KERNEL);
+		if (srmconsp == NULL) {
+			retval = -ENOMEM;
+			break;
+		}
+
+		srmconsp->tty = NULL;
+		srmconsp->lock = SPIN_LOCK_UNLOCKED;
+		init_timer(&srmconsp->timer);
+
+		*ps = srmconsp;
+	} while(0);
+
+	spin_unlock_irqrestore(&srmconsp_lock, flags);
+
+	return retval;
+}
+
+static int
+srmcons_open(struct tty_struct *tty, struct file *filp)
+{
+	struct srmcons_private *srmconsp;
+	unsigned long flags;
+	int retval;
+
+	retval = srmcons_get_private_struct(&srmconsp);
+	if (retval)
+		return retval;
+
+	spin_lock_irqsave(&srmconsp->lock, flags);
+
+	if (!srmconsp->tty) {
+		tty->driver_data = srmconsp;
+
+		srmconsp->tty = tty;
+		srmconsp->timer.function = srmcons_receive_chars;
+		srmconsp->timer.data = (unsigned long)srmconsp;
+		srmconsp->timer.expires = jiffies + 10;
+		add_timer(&srmconsp->timer);
+	}
+
+	spin_unlock_irqrestore(&srmconsp->lock, flags);
+
+	return 0;
+}
+
+static void
+srmcons_close(struct tty_struct *tty, struct file *filp)
+{
+	struct srmcons_private *srmconsp = tty->driver_data;
+	unsigned long flags;
+
+	spin_lock_irqsave(&srmconsp->lock, flags);
+
+	if (tty->count == 1) {
+		srmconsp->tty = NULL;
+		del_timer(&srmconsp->timer);
+	}
+
+	spin_unlock_irqrestore(&srmconsp->lock, flags);
+}
+
+
+static struct tty_driver srmcons_driver = {
+	.driver_name	= "srm",
+	.name		= "srm",
+	.magic		= TTY_DRIVER_MAGIC,
+	.major		= 0, 	/* dynamic */
+	.minor_start	= 0,
+	.num		= MAX_SRM_CONSOLE_DEVICES,
+	.type		= TTY_DRIVER_TYPE_SYSTEM,
+	.subtype	= SYSTEM_TYPE_SYSCONS,
+
+	.table		= srmcons_table,
+	.termios	= srmcons_termios,
+	.termios_locked	= srmcons_termios_locked,
+	.refcount	= &srmcons_refcount,
+
+	.open		= srmcons_open,
+	.close		= srmcons_close,
+	.write		= srmcons_write,
+	.write_room	= srmcons_write_room,
+	.chars_in_buffer= srmcons_chars_in_buffer,
+};
+
+static int __init
+srmcons_init(void)
+{
+	if (srm_is_registered_console) {
+		srmcons_driver.init_termios = tty_std_termios;
+		return tty_register_driver(&srmcons_driver);
+	}
+
+	return -ENODEV;
+}
+
+module_init(srmcons_init);
+
+
+/*
+ * The console driver
+ */
+static void
+srm_console_write(struct console *co, const char *s, unsigned count)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&srmcons_callback_lock, flags);
+	srmcons_do_write(NULL, s, count);
+	spin_unlock_irqrestore(&srmcons_callback_lock, flags);
+}
+
+static kdev_t
+srm_console_device(struct console *co)
+{
+	return mk_kdev(srmcons_driver.major,
+		       srmcons_driver.minor_start + co->index);
+}
+
+static int __init
+srm_console_setup(struct console *co, char *options)
+{
+	return 0;
+}
+
+static struct console srmcons = {
+	.name		= "srm",
+	.write		= srm_console_write,
+	.device		= srm_console_device,
+	.setup		= srm_console_setup,
+	.flags		= CON_PRINTBUFFER,
+	.index		= -1,
+};
+
+void __init
+register_srm_console(void)
+{
+	if (!srm_is_registered_console) {
+		callback_open_console();
+		register_console(&srmcons);
+		srm_is_registered_console = 1;
+	}
+}
+
+void __init
+unregister_srm_console(void)
+{
+	if (srm_is_registered_console) {
+		callback_close_console();
+		unregister_console(&srmcons);
+		srm_is_registered_console = 0;
+	}
+}