drivers/tty/serial/msm_serial_debugger.c - fp2-dev/kernel/msm - Gitiles

 /*
  * drivers/serial/msm_serial_debuger.c
  *
  * Serial Debugger Interface for MSM7K
  *
  * Copyright (C) 2008 Google, Inc.
  *
  * This software is licensed under the terms of the GNU General Public
  * License version 2, as published by the Free Software Foundation, and
  * may be copied, distributed, and modified under those terms.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */

 #include <stdarg.h>
 #include <linux/module.h>
 #include <linux/io.h>
 #include <linux/console.h>
 #include <linux/interrupt.h>
 #include <linux/clk.h>
 #include <linux/platform_device.h>
 #include <linux/kernel_debugger.h>
 #include <linux/kernel_stat.h>
 #include <linux/irq.h>
 #include <linux/delay.h>

 #include <mach/system.h>
 #include <mach/fiq.h>

 #include "msm_serial.h"

 static unsigned int debug_port_base;
 static int debug_signal_irq;
 static struct clk *debug_clk;
 static int debug_enable;
 static int debugger_enable;
 static struct {
 	unsigned int	base;
 	int		irq;
 	struct device	*clk_device;
 	int		signal_irq;
 } init_data;

 static inline void msm_write(unsigned int val, unsigned int off)
 {
 	__raw_writel(val, debug_port_base + off);
 }

 static inline unsigned int msm_read(unsigned int off)
 {
 	return __raw_readl(debug_port_base + off);
 }

 static void debug_port_init(void)
 {
 	/* reset everything */
 	msm_write(UART_CR_CMD_RESET_RX, UART_CR);
 	msm_write(UART_CR_CMD_RESET_TX, UART_CR);
 	msm_write(UART_CR_CMD_RESET_ERR, UART_CR);
 	msm_write(UART_CR_CMD_RESET_BREAK_INT, UART_CR);
 	msm_write(UART_CR_CMD_RESET_CTS, UART_CR);
 	msm_write(UART_CR_CMD_SET_RFR, UART_CR);

 	/* setup clock dividers */
 	if (clk_get_rate(debug_clk) == 19200000) {
 		/* clock is TCXO (19.2MHz) */
 		msm_write(0x06, UART_MREG);
 		msm_write(0xF1, UART_NREG);
 		msm_write(0x0F, UART_DREG);
 		msm_write(0x1A, UART_MNDREG);
 	} else {
 		/* clock must be TCXO/4 */
 		msm_write(0x18, UART_MREG);
 		msm_write(0xF6, UART_NREG);
 		msm_write(0x0F, UART_DREG);
 		msm_write(0x0A, UART_MNDREG);
 	}

 	msm_write(UART_CSR_115200, UART_CSR);

 	/* rx interrupt on every character -- keep it simple */
 	msm_write(0, UART_RFWR);

 	/* enable TX and RX */
 	msm_write(0x05, UART_CR);

 	/* enable RX interrupt */
 	msm_write(UART_IMR_RXLEV, UART_IMR);
 }

 static inline int debug_getc(void)
 {
 	if (msm_read(UART_SR) & UART_SR_RX_READY) {
 		return msm_read(UART_RF);
 	} else {
 		return -1;
 	}
 }

 static inline void debug_putc(unsigned int c)
 {
 	while (!(msm_read(UART_SR) & UART_SR_TX_READY)) ;
 	msm_write(c, UART_TF);
 }

 static inline void debug_flush(void)
 {
 	while (!(msm_read(UART_SR) & UART_SR_TX_EMPTY)) ;
 }

 static void debug_puts(char *s)
 {
 	unsigned c;
 	while ((c = *s++)) {
 		if (c == '\n')
 			debug_putc('\r');
 		debug_putc(c);
 	}
 }

 static void debug_prompt(void)
 {
 	debug_puts("debug> ");
 }

 int log_buf_copy(char *dest, int idx, int len);
 static void dump_kernel_log(void)
 {
 	char buf[1024];
 	int idx = 0;
 	int ret;
 	int saved_oip;

 	/* setting oops_in_progress prevents log_buf_copy()
 	 * from trying to take a spinlock which will make it
 	 * very unhappy in some cases...
 	 */
 	saved_oip = oops_in_progress;
 	oops_in_progress = 1;
 	for (;;) {
 		ret = log_buf_copy(buf, idx, 1023);
 		if (ret <= 0)
 			break;
 		buf[ret] = 0;
 		debug_puts(buf);
 		idx += ret;
 	}
 	oops_in_progress = saved_oip;
 }

 static char *mode_name(unsigned cpsr)
 {
 	switch (cpsr & MODE_MASK) {
 	case USR_MODE: return "USR";
 	case FIQ_MODE: return "FIQ";
 	case IRQ_MODE: return "IRQ";
 	case SVC_MODE: return "SVC";
 	case ABT_MODE: return "ABT";
 	case UND_MODE: return "UND";
 	case SYSTEM_MODE: return "SYS";
 	default: return "???";
 	}
 }

 #define DEBUG_MAX 64
 static char debug_cmd[DEBUG_MAX];
 static int debug_busy;
 static int debug_abort;

 static int debug_printf(void *cookie, const char *fmt, ...)
 {
 	char buf[256];
 	va_list ap;

 	va_start(ap, fmt);
 	vsnprintf(buf, 128, fmt, ap);
 	va_end(ap);

 	debug_puts(buf);
 	return debug_abort;
 }

 /* Safe outside fiq context */
 static int debug_printf_nfiq(void *cookie, const char *fmt, ...)
 {
 	char buf[256];
 	va_list ap;
 	unsigned long irq_flags;

 	va_start(ap, fmt);
 	vsnprintf(buf, 128, fmt, ap);
 	va_end(ap);

 	local_irq_save(irq_flags);
 	debug_puts(buf);
 	debug_flush();
 	local_irq_restore(irq_flags);
 	return debug_abort;
 }

 #define dprintf(fmt...) debug_printf(0, fmt)

 unsigned int last_irqs[NR_IRQS];

 static void dump_irqs(void)
 {
 	int n;
 	dprintf("irqnr       total  since-last   status  name\n");
 	for (n = 1; n < NR_IRQS; n++) {
 		struct irqaction *act = irq_desc[n].action;
 		if (!act && !kstat_cpu(0).irqs[n])
 			continue;
 		dprintf("%5d: %10u %11u %8x  %s\n", n,
 			kstat_cpu(0).irqs[n],
 			kstat_cpu(0).irqs[n] - last_irqs[n],
 			irq_desc[n].status,
 			(act && act->name) ? act->name : "???");
 		last_irqs[n] = kstat_cpu(0).irqs[n];
 	}
 }

 static void debug_exec(const char *cmd, unsigned *regs)
 {
 	if (!strcmp(cmd, "pc")) {
 		dprintf(" pc %08x cpsr %08x mode %s\n",
 			regs[15], regs[16], mode_name(regs[16]));
 	} else if (!strcmp(cmd, "regs")) {
 		dprintf(" r0 %08x  r1 %08x  r2 %08x  r3 %08x\n",
 			regs[0], regs[1], regs[2], regs[3]);
 		dprintf(" r4 %08x  r5 %08x  r6 %08x  r7 %08x\n",
 			regs[4], regs[5], regs[6], regs[7]);
 		dprintf(" r8 %08x  r9 %08x r10 %08x r11 %08x  mode %s\n",
 			regs[8], regs[9], regs[10], regs[11],
 			mode_name(regs[16]));
 		dprintf(" ip %08x  sp %08x  lr %08x  pc %08x  cpsr %08x\n",
 			regs[10], regs[13], regs[14], regs[15], regs[16]);
 	} else if (!strcmp(cmd, "reboot")) {
 		if (msm_hw_reset_hook)
 			msm_hw_reset_hook();
 	} else if (!strcmp(cmd, "irqs")) {
 		dump_irqs();
 	} else if (!strcmp(cmd, "kmsg")) {
 		dump_kernel_log();
 	} else if (!strcmp(cmd, "version")) {
 		dprintf("%s\n", linux_banner);
 	} else {
 		if (debug_busy) {
 			dprintf("command processor busy. trying to abort.\n");
 			debug_abort = -1;
 		} else {
 			strcpy(debug_cmd, cmd);
 			debug_busy = 1;
 		}
 		msm_trigger_irq(debug_signal_irq);
 		return;
 	}
 	debug_prompt();
 }

 static irqreturn_t debug_irq(int irq, void *dev)
 {
 	if (debug_busy) {
 		struct kdbg_ctxt ctxt;

 		ctxt.printf = debug_printf_nfiq;
 		kernel_debugger(&ctxt, debug_cmd);
 		debug_prompt();

 		debug_busy = 0;
 	}
 	return IRQ_HANDLED;
 }

 static char debug_buf[DEBUG_MAX];
 static int debug_count;

 static void debug_fiq(void *data, void *regs)
 {
 	int c;
 	static int last_c;

 	while ((c = debug_getc()) != -1) {
 		if (!debug_enable) {
 			if ((c == 13) || (c == 10)) {
 				debug_enable = true;
 				debug_count = 0;
 				debug_prompt();
 			}
 		} else if ((c >= ' ') && (c < 127)) {
 			if (debug_count < (DEBUG_MAX - 1)) {
 				debug_buf[debug_count++] = c;
 				debug_putc(c);
 			}
 		} else if ((c == 8) || (c == 127)) {
 			if (debug_count > 0) {
 				debug_count--;
 				debug_putc(8);
 				debug_putc(' ');
 				debug_putc(8);
 			}
 		} else if ((c == 13) || (c == 10)) {
 			if (c == '\r' || (c == '\n' && last_c != '\r')) {
 				debug_putc('\r');
 				debug_putc('\n');
 			}
 			if (debug_count) {
 				debug_buf[debug_count] = 0;
 				debug_count = 0;
 				debug_exec(debug_buf, regs);
 			} else {
 				debug_prompt();
 			}
 		}
 		last_c = c;
 	}
 	debug_flush();
 }

 #if defined(CONFIG_MSM_SERIAL_DEBUGGER_CONSOLE)
 static void debug_console_write(struct console *co,
 				const char *s, unsigned int count)
 {
 	unsigned long irq_flags;

 	/* disable irq's while TXing outside of FIQ context */
 	local_irq_save(irq_flags);
 	while (count--) {
 		if (*s == '\n')
 			debug_putc('\r');
 		debug_putc(*s++);
 	}
 	debug_flush();
 	local_irq_restore(irq_flags);
 }

 static struct console msm_serial_debug_console = {
 	.name = "debug_console",
 	.write = debug_console_write,
 	.flags = CON_PRINTBUFFER | CON_ANYTIME | CON_ENABLED,
 };
 #endif

 void msm_serial_debug_enable(int enable) {
 	debug_enable = enable;
 }

 void msm_serial_debug_init(unsigned int base, int irq,
 			   struct device *clk_device, int signal_irq)
 {
 	int ret;
 	void *port;

 	debug_clk = clk_get(clk_device, "uart_clk");
 	if (debug_clk)
 		clk_enable(debug_clk);

 	port = ioremap(base, 4096);
 	if (!port)
 		return;

 	init_data.base = base;
 	init_data.irq = irq;
 	init_data.clk_device = clk_device;
 	init_data.signal_irq = signal_irq;
 	debug_port_base = (unsigned int) port;
 	debug_signal_irq = signal_irq;
 	debug_port_init();

 	debug_prompt();

 	msm_fiq_select(irq);
 	msm_fiq_set_handler(debug_fiq, 0);
 	msm_fiq_enable(irq);

 	ret = request_irq(signal_irq, debug_irq,
 			  IRQF_TRIGGER_RISING, "debug", 0);
 	if (ret)
 		printk(KERN_ERR
 		       "serial_debugger: could not install signal_irq");

 #if defined(CONFIG_MSM_SERIAL_DEBUGGER_CONSOLE)
 	register_console(&msm_serial_debug_console);
 #endif
 	debugger_enable = 1;
 }
 static int msm_serial_debug_remove(const char *val, struct kernel_param *kp)
 {
 	int ret;
 	static int pre_stat = 1;
 	ret = param_set_bool(val, kp);
 	if (ret)
 		return ret;

 	if (pre_stat == *(int *)kp->arg)
 		return 0;

 	pre_stat = *(int *)kp->arg;

 	if (*(int *)kp->arg) {
 		msm_serial_debug_init(init_data.base, init_data.irq,
 				init_data.clk_device, init_data.signal_irq);
 		printk(KERN_INFO "enable FIQ serial debugger\n");
 		return 0;
 	}

 #if defined(CONFIG_MSM_SERIAL_DEBUGGER_CONSOLE)
 	unregister_console(&msm_serial_debug_console);
 #endif
 	free_irq(init_data.signal_irq, 0);
 	msm_fiq_set_handler(NULL, 0);
 	msm_fiq_disable(init_data.irq);
 	msm_fiq_unselect(init_data.irq);
 	clk_disable(debug_clk);
 	printk(KERN_INFO "disable FIQ serial debugger\n");
 	return 0;
 }
 module_param_call(enable, msm_serial_debug_remove, param_get_bool,
 		&debugger_enable, S_IWUSR | S_IRUGO);
	/*
	* drivers/serial/msm_serial_debuger.c
	*
	* Serial Debugger Interface for MSM7K
	*
	* Copyright (C) 2008 Google, Inc.
	*
	* This software is licensed under the terms of the GNU General Public
	* License version 2, as published by the Free Software Foundation, and
	* may be copied, distributed, and modified under those terms.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*/

	#include <stdarg.h>
	#include <linux/module.h>
	#include <linux/io.h>
	#include <linux/console.h>
	#include <linux/interrupt.h>
	#include <linux/clk.h>
	#include <linux/platform_device.h>
	#include <linux/kernel_debugger.h>
	#include <linux/kernel_stat.h>
	#include <linux/irq.h>
	#include <linux/delay.h>

	#include <mach/system.h>
	#include <mach/fiq.h>

	#include "msm_serial.h"

	static unsigned int debug_port_base;
	static int debug_signal_irq;
	static struct clk *debug_clk;
	static int debug_enable;
	static int debugger_enable;
	static struct {
	unsigned int base;
	int irq;
	struct device *clk_device;
	int signal_irq;
	} init_data;

	static inline void msm_write(unsigned int val, unsigned int off)
	{
	__raw_writel(val, debug_port_base + off);
	}

	static inline unsigned int msm_read(unsigned int off)
	{
	return __raw_readl(debug_port_base + off);
	}

	static void debug_port_init(void)
	{
	/* reset everything */
	msm_write(UART_CR_CMD_RESET_RX, UART_CR);
	msm_write(UART_CR_CMD_RESET_TX, UART_CR);
	msm_write(UART_CR_CMD_RESET_ERR, UART_CR);
	msm_write(UART_CR_CMD_RESET_BREAK_INT, UART_CR);
	msm_write(UART_CR_CMD_RESET_CTS, UART_CR);
	msm_write(UART_CR_CMD_SET_RFR, UART_CR);

	/* setup clock dividers */
	if (clk_get_rate(debug_clk) == 19200000) {
	/* clock is TCXO (19.2MHz) */
	msm_write(0x06, UART_MREG);
	msm_write(0xF1, UART_NREG);
	msm_write(0x0F, UART_DREG);
	msm_write(0x1A, UART_MNDREG);
	} else {
	/* clock must be TCXO/4 */
	msm_write(0x18, UART_MREG);
	msm_write(0xF6, UART_NREG);
	msm_write(0x0F, UART_DREG);
	msm_write(0x0A, UART_MNDREG);
	}

	msm_write(UART_CSR_115200, UART_CSR);

	/* rx interrupt on every character -- keep it simple */
	msm_write(0, UART_RFWR);

	/* enable TX and RX */
	msm_write(0x05, UART_CR);

	/* enable RX interrupt */
	msm_write(UART_IMR_RXLEV, UART_IMR);
	}

	static inline int debug_getc(void)
	{
	if (msm_read(UART_SR) & UART_SR_RX_READY) {
	return msm_read(UART_RF);
	} else {
	return -1;
	}
	}

	static inline void debug_putc(unsigned int c)
	{
	while (!(msm_read(UART_SR) & UART_SR_TX_READY)) ;
	msm_write(c, UART_TF);
	}

	static inline void debug_flush(void)
	{
	while (!(msm_read(UART_SR) & UART_SR_TX_EMPTY)) ;
	}

	static void debug_puts(char *s)
	{
	unsigned c;
	while ((c = *s++)) {
	if (c == '\n')
	debug_putc('\r');
	debug_putc(c);
	}
	}

	static void debug_prompt(void)
	{
	debug_puts("debug> ");
	}

	int log_buf_copy(char *dest, int idx, int len);
	static void dump_kernel_log(void)
	{
	char buf[1024];
	int idx = 0;
	int ret;
	int saved_oip;

	/* setting oops_in_progress prevents log_buf_copy()
	* from trying to take a spinlock which will make it
	* very unhappy in some cases...
	*/
	saved_oip = oops_in_progress;
	oops_in_progress = 1;
	for (;;) {
	ret = log_buf_copy(buf, idx, 1023);
	if (ret <= 0)
	break;
	buf[ret] = 0;
	debug_puts(buf);
	idx += ret;
	}
	oops_in_progress = saved_oip;
	}

	static char *mode_name(unsigned cpsr)
	{
	switch (cpsr & MODE_MASK) {
	case USR_MODE: return "USR";
	case FIQ_MODE: return "FIQ";
	case IRQ_MODE: return "IRQ";
	case SVC_MODE: return "SVC";
	case ABT_MODE: return "ABT";
	case UND_MODE: return "UND";
	case SYSTEM_MODE: return "SYS";
	default: return "???";
	}
	}

	#define DEBUG_MAX 64
	static char debug_cmd[DEBUG_MAX];
	static int debug_busy;
	static int debug_abort;

	static int debug_printf(void cookie, const char fmt, ...)
	{
	char buf[256];
	va_list ap;

	va_start(ap, fmt);
	vsnprintf(buf, 128, fmt, ap);
	va_end(ap);

	debug_puts(buf);
	return debug_abort;
	}

	/* Safe outside fiq context */
	static int debug_printf_nfiq(void cookie, const char fmt, ...)
	{
	char buf[256];
	va_list ap;
	unsigned long irq_flags;

	va_start(ap, fmt);
	vsnprintf(buf, 128, fmt, ap);
	va_end(ap);

	local_irq_save(irq_flags);
	debug_puts(buf);
	debug_flush();
	local_irq_restore(irq_flags);
	return debug_abort;
	}

	#define dprintf(fmt...) debug_printf(0, fmt)

	unsigned int last_irqs[NR_IRQS];

	static void dump_irqs(void)
	{
	int n;
	dprintf("irqnr total since-last status name\n");
	for (n = 1; n < NR_IRQS; n++) {
	struct irqaction *act = irq_desc[n].action;
	if (!act && !kstat_cpu(0).irqs[n])
	continue;
	dprintf("%5d: %10u %11u %8x %s\n", n,
	kstat_cpu(0).irqs[n],
	kstat_cpu(0).irqs[n] - last_irqs[n],
	irq_desc[n].status,
	(act && act->name) ? act->name : "???");
	last_irqs[n] = kstat_cpu(0).irqs[n];
	}
	}

	static void debug_exec(const char cmd, unsigned regs)
	{
	if (!strcmp(cmd, "pc")) {
	dprintf(" pc %08x cpsr %08x mode %s\n",
	regs[15], regs[16], mode_name(regs[16]));
	} else if (!strcmp(cmd, "regs")) {
	dprintf(" r0 %08x r1 %08x r2 %08x r3 %08x\n",
	regs[0], regs[1], regs[2], regs[3]);
	dprintf(" r4 %08x r5 %08x r6 %08x r7 %08x\n",
	regs[4], regs[5], regs[6], regs[7]);
	dprintf(" r8 %08x r9 %08x r10 %08x r11 %08x mode %s\n",
	regs[8], regs[9], regs[10], regs[11],
	mode_name(regs[16]));
	dprintf(" ip %08x sp %08x lr %08x pc %08x cpsr %08x\n",
	regs[10], regs[13], regs[14], regs[15], regs[16]);
	} else if (!strcmp(cmd, "reboot")) {
	if (msm_hw_reset_hook)
	msm_hw_reset_hook();
	} else if (!strcmp(cmd, "irqs")) {
	dump_irqs();
	} else if (!strcmp(cmd, "kmsg")) {
	dump_kernel_log();
	} else if (!strcmp(cmd, "version")) {
	dprintf("%s\n", linux_banner);
	} else {
	if (debug_busy) {
	dprintf("command processor busy. trying to abort.\n");
	debug_abort = -1;
	} else {
	strcpy(debug_cmd, cmd);
	debug_busy = 1;
	}
	msm_trigger_irq(debug_signal_irq);
	return;
	}
	debug_prompt();
	}

	static irqreturn_t debug_irq(int irq, void *dev)
	{
	if (debug_busy) {
	struct kdbg_ctxt ctxt;

	ctxt.printf = debug_printf_nfiq;
	kernel_debugger(&ctxt, debug_cmd);
	debug_prompt();

	debug_busy = 0;
	}
	return IRQ_HANDLED;
	}

	static char debug_buf[DEBUG_MAX];
	static int debug_count;

	static void debug_fiq(void data, void regs)
	{
	int c;
	static int last_c;

	while ((c = debug_getc()) != -1) {
	if (!debug_enable) {
	if ((c == 13) \|\| (c == 10)) {
	debug_enable = true;
	debug_count = 0;
	debug_prompt();
	}
	} else if ((c >= ' ') && (c < 127)) {
	if (debug_count < (DEBUG_MAX - 1)) {
	debug_buf[debug_count++] = c;
	debug_putc(c);
	}
	} else if ((c == 8) \|\| (c == 127)) {
	if (debug_count > 0) {
	debug_count--;
	debug_putc(8);
	debug_putc(' ');
	debug_putc(8);
	}
	} else if ((c == 13) \|\| (c == 10)) {
	if (c == '\r' \|\| (c == '\n' && last_c != '\r')) {
	debug_putc('\r');
	debug_putc('\n');
	}
	if (debug_count) {
	debug_buf[debug_count] = 0;
	debug_count = 0;
	debug_exec(debug_buf, regs);
	} else {
	debug_prompt();
	}
	}
	last_c = c;
	}
	debug_flush();
	}

	#if defined(CONFIG_MSM_SERIAL_DEBUGGER_CONSOLE)
	static void debug_console_write(struct console *co,
	const char *s, unsigned int count)
	{
	unsigned long irq_flags;

	/* disable irq's while TXing outside of FIQ context */
	local_irq_save(irq_flags);
	while (count--) {
	if (*s == '\n')
	debug_putc('\r');
	debug_putc(*s++);
	}
	debug_flush();
	local_irq_restore(irq_flags);
	}

	static struct console msm_serial_debug_console = {
	.name = "debug_console",
	.write = debug_console_write,
	.flags = CON_PRINTBUFFER \| CON_ANYTIME \| CON_ENABLED,
	};
	#endif

	void msm_serial_debug_enable(int enable) {
	debug_enable = enable;
	}

	void msm_serial_debug_init(unsigned int base, int irq,
	struct device *clk_device, int signal_irq)
	{
	int ret;
	void *port;

	debug_clk = clk_get(clk_device, "uart_clk");
	if (debug_clk)
	clk_enable(debug_clk);

	port = ioremap(base, 4096);
	if (!port)
	return;

	init_data.base = base;
	init_data.irq = irq;
	init_data.clk_device = clk_device;
	init_data.signal_irq = signal_irq;
	debug_port_base = (unsigned int) port;
	debug_signal_irq = signal_irq;
	debug_port_init();

	debug_prompt();

	msm_fiq_select(irq);
	msm_fiq_set_handler(debug_fiq, 0);
	msm_fiq_enable(irq);

	ret = request_irq(signal_irq, debug_irq,
	IRQF_TRIGGER_RISING, "debug", 0);
	if (ret)
	printk(KERN_ERR
	"serial_debugger: could not install signal_irq");

	#if defined(CONFIG_MSM_SERIAL_DEBUGGER_CONSOLE)
	register_console(&msm_serial_debug_console);
	#endif
	debugger_enable = 1;
	}
	static int msm_serial_debug_remove(const char val, struct kernel_param kp)
	{
	int ret;
	static int pre_stat = 1;
	ret = param_set_bool(val, kp);
	if (ret)
	return ret;

	if (pre_stat == (int )kp->arg)
	return 0;

	pre_stat = (int )kp->arg;

	if ((int )kp->arg) {
	msm_serial_debug_init(init_data.base, init_data.irq,
	init_data.clk_device, init_data.signal_irq);
	printk(KERN_INFO "enable FIQ serial debugger\n");
	return 0;
	}

	#if defined(CONFIG_MSM_SERIAL_DEBUGGER_CONSOLE)
	unregister_console(&msm_serial_debug_console);
	#endif
	free_irq(init_data.signal_irq, 0);
	msm_fiq_set_handler(NULL, 0);
	msm_fiq_disable(init_data.irq);
	msm_fiq_unselect(init_data.irq);
	clk_disable(debug_clk);
	printk(KERN_INFO "disable FIQ serial debugger\n");
	return 0;
	}
	module_param_call(enable, msm_serial_debug_remove, param_get_bool,
	&debugger_enable, S_IWUSR \| S_IRUGO);