[apple/xnu.git] / osfmk / console / i386 / serial_console.c

/*
 * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */

#include <i386/mp.h>
#include <i386/cpu_data.h>
#include <i386/machine_cpu.h>
#include <i386/machine_routines.h>
#include <i386/misc_protos.h>
#include <vm/vm_kern.h>
#include <console/video_console.h>
#include <console/serial_protos.h>
#include <kern/kalloc.h>

static struct {
	char	*buffer;
	int	len;
	int	used;
	char	*write_ptr;
	char	*read_ptr;
	decl_simple_lock_data(,read_lock);
	decl_simple_lock_data(,write_lock);
} console_ring;

hw_lock_data_t cnputc_lock;
static volatile long console_output = 0;

typedef struct console_buf {
	char	*buf_base;
	char	*buf_end;
	char	*buf_ptr;
#define CPU_BUFFER_LEN	(256 - 3*(sizeof(char*)))
	char	buf[CPU_BUFFER_LEN];
} console_buf_t;

extern int serial_getc(void);
extern void serial_putc(int);

static void _serial_putc(int, int, int);

int vcgetc(int, int, boolean_t, boolean_t);

console_ops_t cons_ops[] = {
    {_serial_putc, _serial_getc},
    {vcputc, vcgetc}
};

uint32_t nconsops = (sizeof cons_ops / sizeof cons_ops[0]);

uint32_t cons_ops_index = VC_CONS_OPS;

/* This macro polls for pending TLB flushes while spinning on a lock
 */
#define SIMPLE_LOCK_NO_INTRS(l)				\
MACRO_BEGIN						\
	boolean_t istate = ml_get_interrupts_enabled();	\
	while (!simple_lock_try((l)))			\
	{						\
		if (!istate)				\
			handle_pending_TLB_flushes();	\
		cpu_pause();				\
	}						\
MACRO_END

void
console_init(void)
{
	int	ret;

	console_ring.len = PAGE_SIZE;
	ret = kmem_alloc(kernel_map, (vm_offset_t *) &console_ring.buffer,
			 console_ring.len);
	if (ret != KERN_SUCCESS)
		panic("console_ring_init() "
		      "failed to allocate ring buffer, error %d\n", ret);
	console_ring.used = 0;
	console_ring.read_ptr = console_ring.buffer;
	console_ring.write_ptr = console_ring.buffer;
	simple_lock_init(&console_ring.read_lock, 0);
	simple_lock_init(&console_ring.write_lock, 0);
	hw_lock_init(&cnputc_lock);
}

void *
console_cpu_alloc(__unused boolean_t boot_processor)
{
	int		ret;
	console_buf_t	*cbp;

	ret = kmem_alloc(kernel_map, (vm_offset_t *) &cbp,
				sizeof(console_buf_t));
	if (ret != KERN_SUCCESS) {
		printf("console_cpu_alloc() "
		      "failed to allocate cpu buffer, error=%d\n", ret);
		return NULL;
	}

	cbp->buf_base = (char *) &cbp->buf;
	cbp->buf_ptr = cbp->buf_base;
	cbp->buf_end = cbp->buf_base + CPU_BUFFER_LEN;

	return (void *) cbp;
}

void
console_cpu_free(void *buf)
{
	if (buf != NULL)
		kfree((void *) buf, sizeof(console_buf_t));
}

static inline int
console_ring_space(void)
{
	return console_ring.len - console_ring.used;
}

static boolean_t
console_ring_put(char ch)
{
	if (console_ring.used < console_ring.len) {
		console_ring.used++;;
		*console_ring.write_ptr++ = ch;
		if (console_ring.write_ptr - console_ring.buffer
		    == console_ring.len)
			console_ring.write_ptr = console_ring.buffer;
		return TRUE;
	} else {
		return FALSE;
	}
}

static int
console_ring_get(void)
{
	char	ch = 0;

	if (console_ring.used > 0) {
		console_ring.used--;
		ch = *console_ring.read_ptr++;
		if (console_ring.read_ptr - console_ring.buffer
		    == console_ring.len)
			console_ring.read_ptr = console_ring.buffer;
	}
	return (int) ch;	
}

static inline void
cpu_buffer_put(console_buf_t *cbp, char ch)
{
	if (ch != '\0' && cbp->buf_ptr < cbp->buf_end)
		*(cbp->buf_ptr++) = ch;
}

static inline void
_cnputc(char c)
{
	/* The console device output routines are assumed to be
	 * non-reentrant.
	 */
	mp_disable_preemption();
	if (!hw_lock_to(&cnputc_lock, LockTimeOut*10)) {
	/* If we timed out on the lock, and we're in the debugger,
	 * break the lock.
	 */
		if (debug_mode) {
			/* Since hw_lock_to takes a pre-emption count...*/
			mp_enable_preemption(); 
			hw_lock_init(&cnputc_lock);
			hw_lock_lock(&cnputc_lock);
		}
		else
			panic("Lock acquire timeout in _cnputc()");
	}
	cons_ops[cons_ops_index].putc(0, 0, c);
	if (c == '\n')
            cons_ops[cons_ops_index].putc(0, 0, '\r');
	hw_lock_unlock(&cnputc_lock);
	mp_enable_preemption();
}

void
cnputcusr(char c)
{
	/* Spin (with pre-emption enabled) waiting for console_ring_try_empty()
	 * to complete output. There is a small window here where we could
	 * end up with a stale value of console_output, but it's unlikely,
	 * and _cnputc(), which outputs to the console device, is internally
	 * synchronized. There's something of a conflict between the
	 * character-at-a-time (with pre-emption enabled) unbuffered
	 * output model here, and the buffered output from cnputc(),
	 * whose consumers include printf() ( which outputs a sequence
	 * with pre-emption disabled, and should be safe to call with
	 * interrupts off); we don't want to disable pre-emption indefinitely
	 * here, and spinlocks and mutexes are inappropriate.
	 */
	while (console_output != 0);

	_cnputc(c);
}

static void
console_ring_try_empty(void)
{
	boolean_t state = ml_get_interrupts_enabled();
	/*
	 * Try to get the read lock on the ring buffer to empty it.
	 * If this fails someone else is already emptying...
	 */
	if (!simple_lock_try(&console_ring.read_lock))
		return;
	/* Indicate that we're in the process of writing a block of data
	 * to the console.
	 */
	atomic_incl(&console_output, 1);
	for (;;) {
		char	ch;
		if (!state)
			handle_pending_TLB_flushes();
   	 	SIMPLE_LOCK_NO_INTRS(&console_ring.write_lock);
		ch = console_ring_get();
    		simple_unlock(&console_ring.write_lock);
		if (ch == 0)
			break;
		_cnputc(ch);
	}
	atomic_decl(&console_output, 1);
	simple_unlock(&console_ring.read_lock);
}

void
cnputc(char c)
{
	console_buf_t	*cbp;
#if MACH_KDB
	/* Bypass locking/buffering if in debugger */
	if (kdb_cpu == cpu_number()) {
		_cnputc(c);
		return;
	}
#endif /* MACH_KDB */	
	mp_disable_preemption();
	cbp = (console_buf_t *) current_cpu_datap()->cpu_console_buf;
	if (cbp == NULL) {
		mp_enable_preemption();
		/* Put directly if console ring is not initialized */
		_cnputc(c);
		return;
	}

	/* add to stack buf */
	if (c != '\n') {
		/* XXX - cpu_buffer_put() can fail silently if the buffer
		 * is exhausted, as can happen if there's a long sequence
		 * of data with no newlines. We should, instead, attempt
		 * a flush.
		 */
		cpu_buffer_put(cbp, c);
	} else {
		boolean_t	state;
		char		*cp;

		/* Here at end of printf -- time to try to output */
	
		/* copy this buffer into the shared ring buffer */
		state = ml_set_interrupts_enabled(FALSE);
		SIMPLE_LOCK_NO_INTRS(&console_ring.write_lock);

		/*
		 * Is there enough space in the shared ring buffer?
		 * Try to empty if not.
		 * Note, we want the entire local buffer to fit to
		 * avoid another cpu interjecting.
		 */
		while (cbp->buf_ptr-cbp->buf_base + 1 > console_ring_space()) {
			simple_unlock(&console_ring.write_lock);
			console_ring_try_empty();
			SIMPLE_LOCK_NO_INTRS(&console_ring.write_lock);
		}
		for (cp = cbp->buf_base; cp < cbp->buf_ptr; cp++)
			console_ring_put(*cp);
		console_ring_put('\n');
		cbp->buf_ptr = cbp->buf_base;
		simple_unlock(&console_ring.write_lock);
		ml_set_interrupts_enabled(state);
	}
	console_ring_try_empty();
	mp_enable_preemption();
}

int _serial_getc(__unused int a, __unused int b, boolean_t wait, __unused boolean_t raw)
{
    int c;
    do {
        c = serial_getc();
    } while (wait && c < 0);

    return c;
}

static void _serial_putc(__unused int a, __unused int b, int c)
{
    serial_putc(c);
}


int
cngetc(void)
{
	return cons_ops[cons_ops_index].getc(0, 0,
					     TRUE, FALSE);
}

int
cnmaygetc(void)
{
	return cons_ops[cons_ops_index].getc(0, 0,
					     FALSE, FALSE);
}

int
vcgetc(__unused int l, 
       __unused int u, 
       __unused boolean_t wait, 
       __unused boolean_t raw)
{
	char c;

	if( 0 == (*PE_poll_input)( 0, &c))
		return( c);
	else
		return( 0);
}
Commit	Line	Data
1c79356b	1	/*
55e303ae	2	* Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
1c79356b	3	*
6601e61a	4	* @APPLE_LICENSE_HEADER_START@
1c79356b	5	*
6601e61a A	6	* The contents of this file constitute Original Code as defined in and
	7	* are subject to the Apple Public Source License Version 1.1 (the
	8	* "License"). You may not use this file except in compliance with the
	9	* License. Please obtain a copy of the License at
	10	* http://www.apple.com/publicsource and read it before using this file.
8f6c56a5	11	*
6601e61a A	12	* This Original Code and all software distributed under the License are
6601e61a A	13	* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
8f6c56a5 A	14	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
8f6c56a5 A	15	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
6601e61a A	16	* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
	17	* License for the specific language governing rights and limitations
	18	* under the License.
8f6c56a5	19	*
6601e61a	20	* @APPLE_LICENSE_HEADER_END@
1c79356b	21	*/
1c79356b	22
55e303ae	23	#include <i386/mp.h>
91447636 A	24	#include <i386/cpu_data.h>
91447636 A	25	#include <i386/machine_cpu.h>
55e303ae	26	#include <i386/machine_routines.h>
91447636 A	27	#include <i386/misc_protos.h>
	28	#include <vm/vm_kern.h>
	29	#include <console/video_console.h>
0c530ab8	30	#include <console/serial_protos.h>
91447636 A	31	#include <kern/kalloc.h>
	32
	33	static struct {
	34	char *buffer;
	35	int len;
	36	int used;
	37	char *write_ptr;
	38	char *read_ptr;
	39	decl_simple_lock_data(,read_lock);
	40	decl_simple_lock_data(,write_lock);
	41	} console_ring;
	42
0c530ab8 A	43	hw_lock_data_t cnputc_lock;
	44	static volatile long console_output = 0;
	45
91447636 A	46	typedef struct console_buf {
	47	char *buf_base;
	48	char *buf_end;
	49	char *buf_ptr;
	50	#define CPU_BUFFER_LEN (256 - 3(sizeof(char)))
	51	char buf[CPU_BUFFER_LEN];
	52	} console_buf_t;
1c79356b	53
0c530ab8 A	54	extern int serial_getc(void);
	55	extern void serial_putc(int);
	56
	57	static void _serial_putc(int, int, int);
	58
	59	int vcgetc(int, int, boolean_t, boolean_t);
	60
	61	console_ops_t cons_ops[] = {
	62	{_serial_putc, _serial_getc},
	63	{vcputc, vcgetc}
	64	};
	65
	66	uint32_t nconsops = (sizeof cons_ops / sizeof cons_ops[0]);
	67
	68	uint32_t cons_ops_index = VC_CONS_OPS;
	69
	70	/* This macro polls for pending TLB flushes while spinning on a lock
	71	*/
	72	#define SIMPLE_LOCK_NO_INTRS(l) \
	73	MACRO_BEGIN \
	74	boolean_t istate = ml_get_interrupts_enabled(); \
	75	while (!simple_lock_try((l))) \
	76	{ \
	77	if (!istate) \
	78	handle_pending_TLB_flushes(); \
	79	cpu_pause(); \
	80	} \
	81	MACRO_END
	82
55e303ae	83	void
91447636 A	84	console_init(void)
	85	{
	86	int ret;
	87
	88	console_ring.len = PAGE_SIZE;
	89	ret = kmem_alloc(kernel_map, (vm_offset_t *) &console_ring.buffer,
	90	console_ring.len);
	91	if (ret != KERN_SUCCESS)
	92	panic("console_ring_init() "
	93	"failed to allocate ring buffer, error %d\n", ret);
	94	console_ring.used = 0;
	95	console_ring.read_ptr = console_ring.buffer;
	96	console_ring.write_ptr = console_ring.buffer;
	97	simple_lock_init(&console_ring.read_lock, 0);
	98	simple_lock_init(&console_ring.write_lock, 0);
0c530ab8	99	hw_lock_init(&cnputc_lock);
91447636 A	100	}
	101
	102	void *
	103	console_cpu_alloc(__unused boolean_t boot_processor)
	104	{
	105	int ret;
	106	console_buf_t *cbp;
	107
	108	ret = kmem_alloc(kernel_map, (vm_offset_t *) &cbp,
	109	sizeof(console_buf_t));
	110	if (ret != KERN_SUCCESS) {
	111	printf("console_cpu_alloc() "
	112	"failed to allocate cpu buffer, error=%d\n", ret);
	113	return NULL;
	114	}
	115
	116	cbp->buf_base = (char *) &cbp->buf;
	117	cbp->buf_ptr = cbp->buf_base;
	118	cbp->buf_end = cbp->buf_base + CPU_BUFFER_LEN;
	119
	120	return (void *) cbp;
	121	}
	122
	123	void
	124	console_cpu_free(void *buf)
	125	{
	126	if (buf != NULL)
	127	kfree((void *) buf, sizeof(console_buf_t));
	128	}
	129
0c530ab8 A	130	static inline int
	131	console_ring_space(void)
	132	{
	133	return console_ring.len - console_ring.used;
	134	}
	135
91447636 A	136	static boolean_t
	137	console_ring_put(char ch)
	138	{
	139	if (console_ring.used < console_ring.len) {
	140	console_ring.used++;;
	141	*console_ring.write_ptr++ = ch;
	142	if (console_ring.write_ptr - console_ring.buffer
	143	== console_ring.len)
	144	console_ring.write_ptr = console_ring.buffer;
	145	return TRUE;
	146	} else {
	147	return FALSE;
	148	}
	149	}
	150
	151	static int
	152	console_ring_get(void)
	153	{
	154	char ch = 0;
	155
	156	if (console_ring.used > 0) {
	157	console_ring.used--;
	158	ch = *console_ring.read_ptr++;
	159	if (console_ring.read_ptr - console_ring.buffer
	160	== console_ring.len)
	161	console_ring.read_ptr = console_ring.buffer;
	162	}
	163	return (int) ch;
	164	}
	165
	166	static inline void
	167	cpu_buffer_put(console_buf_t *cbp, char ch)
	168	{
0c530ab8	169	if (ch != '\0' && cbp->buf_ptr < cbp->buf_end)
91447636 A	170	*(cbp->buf_ptr++) = ch;
	171	}
	172
	173	static inline void
	174	_cnputc(char c)
1c79356b	175	{
0c530ab8 A	176	/* The console device output routines are assumed to be
	177	* non-reentrant.
	178	*/
	179	mp_disable_preemption();
	180	if (!hw_lock_to(&cnputc_lock, LockTimeOut*10)) {
	181	/* If we timed out on the lock, and we're in the debugger,
	182	* break the lock.
	183	*/
	184	if (debug_mode) {
	185	/* Since hw_lock_to takes a pre-emption count...*/
	186	mp_enable_preemption();
	187	hw_lock_init(&cnputc_lock);
	188	hw_lock_lock(&cnputc_lock);
	189	}
	190	else
	191	panic("Lock acquire timeout in _cnputc()");
	192	}
	193	cons_ops[cons_ops_index].putc(0, 0, c);
55e303ae	194	if (c == '\n')
0c530ab8 A	195	cons_ops[cons_ops_index].putc(0, 0, '\r');
	196	hw_lock_unlock(&cnputc_lock);
	197	mp_enable_preemption();
91447636 A	198	}
	199
	200	void
	201	cnputcusr(char c)
0c530ab8 A	202	{
	203	/* Spin (with pre-emption enabled) waiting for console_ring_try_empty()
	204	* to complete output. There is a small window here where we could
	205	* end up with a stale value of console_output, but it's unlikely,
	206	* and _cnputc(), which outputs to the console device, is internally
	207	* synchronized. There's something of a conflict between the
	208	* character-at-a-time (with pre-emption enabled) unbuffered
	209	* output model here, and the buffered output from cnputc(),
	210	* whose consumers include printf() ( which outputs a sequence
	211	* with pre-emption disabled, and should be safe to call with
	212	* interrupts off); we don't want to disable pre-emption indefinitely
	213	* here, and spinlocks and mutexes are inappropriate.
	214	*/
	215	while (console_output != 0);
	216
91447636	217	_cnputc(c);
0c530ab8 A	218	}
	219
	220	static void
	221	console_ring_try_empty(void)
	222	{
	223	boolean_t state = ml_get_interrupts_enabled();
	224	/*
	225	* Try to get the read lock on the ring buffer to empty it.
	226	* If this fails someone else is already emptying...
	227	*/
	228	if (!simple_lock_try(&console_ring.read_lock))
	229	return;
	230	/* Indicate that we're in the process of writing a block of data
	231	* to the console.
	232	*/
	233	atomic_incl(&console_output, 1);
	234	for (;;) {
	235	char ch;
	236	if (!state)
	237	handle_pending_TLB_flushes();
	238	SIMPLE_LOCK_NO_INTRS(&console_ring.write_lock);
	239	ch = console_ring_get();
	240	simple_unlock(&console_ring.write_lock);
	241	if (ch == 0)
	242	break;
	243	_cnputc(ch);
	244	}
	245	atomic_decl(&console_output, 1);
91447636 A	246	simple_unlock(&console_ring.read_lock);
	247	}
	248
	249	void
	250	cnputc(char c)
	251	{
	252	console_buf_t *cbp;
0c530ab8 A	253	#if MACH_KDB
	254	/* Bypass locking/buffering if in debugger */
	255	if (kdb_cpu == cpu_number()) {
4452a7af A	256	_cnputc(c);
	257	return;
	258	}
0c530ab8	259	#endif /* MACH_KDB */
6601e61a	260	mp_disable_preemption();
6601e61a	261	cbp = (console_buf_t *) current_cpu_datap()->cpu_console_buf;
0c530ab8 A	262	if (cbp == NULL) {
	263	mp_enable_preemption();
	264	/* Put directly if console ring is not initialized */
	265	_cnputc(c);
	266	return;
	267	}
	268
	269	/* add to stack buf */
91447636	270	if (c != '\n') {
0c530ab8 A	271	/* XXX - cpu_buffer_put() can fail silently if the buffer
	272	* is exhausted, as can happen if there's a long sequence
	273	* of data with no newlines. We should, instead, attempt
	274	* a flush.
	275	*/
91447636 A	276	cpu_buffer_put(cbp, c);
	277	} else {
	278	boolean_t state;
	279	char *cp;
	280
	281	/* Here at end of printf -- time to try to output */
	282
	283	/* copy this buffer into the shared ring buffer */
	284	state = ml_set_interrupts_enabled(FALSE);
0c530ab8	285	SIMPLE_LOCK_NO_INTRS(&console_ring.write_lock);
91447636 A	286
91447636 A	287	/*
0c530ab8 A	288	* Is there enough space in the shared ring buffer?
	289	* Try to empty if not.
	290	* Note, we want the entire local buffer to fit to
	291	* avoid another cpu interjecting.
91447636	292	*/
0c530ab8 A	293	while (cbp->buf_ptr-cbp->buf_base + 1 > console_ring_space()) {
	294	simple_unlock(&console_ring.write_lock);
	295	console_ring_try_empty();
	296	SIMPLE_LOCK_NO_INTRS(&console_ring.write_lock);
91447636	297	}
0c530ab8 A	298	for (cp = cbp->buf_base; cp < cbp->buf_ptr; cp++)
	299	console_ring_put(*cp);
	300	console_ring_put('\n');
	301	cbp->buf_ptr = cbp->buf_base;
	302	simple_unlock(&console_ring.write_lock);
	303	ml_set_interrupts_enabled(state);
91447636	304	}
0c530ab8	305	console_ring_try_empty();
91447636	306	mp_enable_preemption();
55e303ae	307	}
0c530ab8 A	308
	309	int _serial_getc(__unused int a, __unused int b, boolean_t wait, __unused boolean_t raw)
	310	{
	311	int c;
	312	do {
	313	c = serial_getc();
	314	} while (wait && c < 0);
	315
	316	return c;
	317	}
	318
	319	static void _serial_putc(__unused int a, __unused int b, int c)
	320	{
	321	serial_putc(c);
	322	}
	323
	324
	325	int
	326	cngetc(void)
	327	{
	328	return cons_ops[cons_ops_index].getc(0, 0,
	329	TRUE, FALSE);
	330	}
	331
	332	int
	333	cnmaygetc(void)
	334	{
	335	return cons_ops[cons_ops_index].getc(0, 0,
	336	FALSE, FALSE);
	337	}
	338
	339	int
	340	vcgetc(__unused int l,
	341	__unused int u,
	342	__unused boolean_t wait,
	343	__unused boolean_t raw)
	344	{
	345	char c;
	346
	347	if( 0 == (*PE_poll_input)( 0, &c))
	348	return( c);
	349	else
	350	return( 0);
	351	}