[linux-2.6-block.git] / drivers / tty / hvc / hvc_dcc.c

/* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

#include <linux/console.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/types.h>

#include <asm/processor.h>

#include "hvc_console.h"

/* DCC Status Bits */
#define DCC_STATUS_RX		(1 << 30)
#define DCC_STATUS_TX		(1 << 29)

static inline u32 __dcc_getstatus(void)
{
	u32 __ret;
	asm volatile("mrc p14, 0, %0, c0, c1, 0	@ read comms ctrl reg"
		: "=r" (__ret) : : "cc");

	return __ret;
}


static inline char __dcc_getchar(void)
{
	char __c;

	asm volatile("mrc p14, 0, %0, c0, c5, 0	@ read comms data reg"
		: "=r" (__c));
	isb();

	return __c;
}

static inline void __dcc_putchar(char c)
{
	asm volatile("mcr p14, 0, %0, c0, c5, 0	@ write a char"
		: /* no output register */
		: "r" (c));
	isb();
}

static int hvc_dcc_put_chars(uint32_t vt, const char *buf, int count)
{
	int i;

	for (i = 0; i < count; i++) {
		while (__dcc_getstatus() & DCC_STATUS_TX)
			cpu_relax();

		__dcc_putchar(buf[i]);
	}

	return count;
}

static int hvc_dcc_get_chars(uint32_t vt, char *buf, int count)
{
	int i;

	for (i = 0; i < count; ++i)
		if (__dcc_getstatus() & DCC_STATUS_RX)
			buf[i] = __dcc_getchar();
		else
			break;

	return i;
}

static const struct hv_ops hvc_dcc_get_put_ops = {
	.get_chars = hvc_dcc_get_chars,
	.put_chars = hvc_dcc_put_chars,
};

static int __init hvc_dcc_console_init(void)
{
	hvc_instantiate(0, 0, &hvc_dcc_get_put_ops);
	return 0;
}
console_initcall(hvc_dcc_console_init);

static int __init hvc_dcc_init(void)
{
	hvc_alloc(0, 0, &hvc_dcc_get_put_ops, 128);
	return 0;
}
device_initcall(hvc_dcc_init);
Commit	Line	Data
16c63f8e DW	1	/* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
	2	*
	3	* This program is free software; you can redistribute it and/or modify
	4	* it under the terms of the GNU General Public License version 2 and
	5	* only version 2 as published by the Free Software Foundation.
	6	*
	7	* This program is distributed in the hope that it will be useful,
	8	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	9	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	10	* GNU General Public License for more details.
	11	*
	12	* You should have received a copy of the GNU General Public License
	13	* along with this program; if not, write to the Free Software
	14	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
	15	* 02110-1301, USA.
	16	*/
	17
	18	#include <linux/console.h>
	19	#include <linux/delay.h>
	20	#include <linux/err.h>
	21	#include <linux/init.h>
	22	#include <linux/moduleparam.h>
	23	#include <linux/types.h>
	24
	25	#include <asm/processor.h>
	26
	27	#include "hvc_console.h"
	28
	29	/* DCC Status Bits */
	30	#define DCC_STATUS_RX (1 << 30)
	31	#define DCC_STATUS_TX (1 << 29)
	32
	33	static inline u32 __dcc_getstatus(void)
	34	{
	35	u32 __ret;
a9963201	36	asm volatile("mrc p14, 0, %0, c0, c1, 0 @ read comms ctrl reg"
16c63f8e DW	37	: "=r" (__ret) : : "cc");
	38
	39	return __ret;
	40	}
	41
	42
16c63f8e DW	43	static inline char __dcc_getchar(void)
	44	{
	45	char __c;
	46
a9963201	47	asm volatile("mrc p14, 0, %0, c0, c5, 0 @ read comms data reg"
16c63f8e	48	: "=r" (__c));
c2a3e84f	49	isb();
16c63f8e DW	50
	51	return __c;
	52	}
16c63f8e	53
16c63f8e DW	54	static inline void __dcc_putchar(char c)
16c63f8e DW	55	{
a9963201	56	asm volatile("mcr p14, 0, %0, c0, c5, 0 @ write a char"
16c63f8e DW	57	: /* no output register */
16c63f8e DW	58	: "r" (c));
c2a3e84f	59	isb();
16c63f8e	60	}
16c63f8e DW	61
	62	static int hvc_dcc_put_chars(uint32_t vt, const char *buf, int count)
	63	{
	64	int i;
	65
	66	for (i = 0; i < count; i++) {
	67	while (__dcc_getstatus() & DCC_STATUS_TX)
	68	cpu_relax();
	69
bf73bd35	70	__dcc_putchar(buf[i]);
16c63f8e DW	71	}
	72
	73	return count;
	74	}
	75
	76	static int hvc_dcc_get_chars(uint32_t vt, char *buf, int count)
	77	{
	78	int i;
	79
bf73bd35	80	for (i = 0; i < count; ++i)
16c63f8e	81	if (__dcc_getstatus() & DCC_STATUS_RX)
bf73bd35 SB	82	buf[i] = __dcc_getchar();
bf73bd35 SB	83	else
16c63f8e	84	break;
16c63f8e DW	85
	86	return i;
	87	}
	88
	89	static const struct hv_ops hvc_dcc_get_put_ops = {
	90	.get_chars = hvc_dcc_get_chars,
	91	.put_chars = hvc_dcc_put_chars,
	92	};
	93
	94	static int __init hvc_dcc_console_init(void)
	95	{
	96	hvc_instantiate(0, 0, &hvc_dcc_get_put_ops);
	97	return 0;
	98	}
	99	console_initcall(hvc_dcc_console_init);
	100
	101	static int __init hvc_dcc_init(void)
	102	{
	103	hvc_alloc(0, 0, &hvc_dcc_get_put_ops, 128);
	104	return 0;
	105	}
	106	device_initcall(hvc_dcc_init);