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
 33static inline u32 __dcc_getstatus(void)
 34{
 35	u32 __ret;
 36	asm volatile("mrc p14, 0, %0, c0, c1, 0	@ read comms ctrl reg"
 37		: "=r" (__ret) : : "cc");
 38
 39	return __ret;
 40}
 41
 42
 43static inline char __dcc_getchar(void)
 44{
 45	char __c;
 46
 47	asm volatile("mrc p14, 0, %0, c0, c5, 0	@ read comms data reg"
 48		: "=r" (__c));
 
 49
 50	return __c;
 51}
 52
 53static inline void __dcc_putchar(char c)
 54{
 55	asm volatile("mcr p14, 0, %0, c0, c5, 0	@ write a char"
 56		: /* no output register */
 57		: "r" (c));
 
 58}
 59
 60static int hvc_dcc_put_chars(uint32_t vt, const char *buf, int count)
 61{
 62	int i;
 63
 64	for (i = 0; i < count; i++) {
 65		while (__dcc_getstatus() & DCC_STATUS_TX)
 66			cpu_relax();
 67
 68		__dcc_putchar(buf[i]);
 69	}
 70
 71	return count;
 72}
 73
 74static int hvc_dcc_get_chars(uint32_t vt, char *buf, int count)
 75{
 76	int i;
 77
 78	for (i = 0; i < count; ++i)
 79		if (__dcc_getstatus() & DCC_STATUS_RX)
 80			buf[i] = __dcc_getchar();
 81		else
 82			break;
 83
 84	return i;
 85}
 86
 87static const struct hv_ops hvc_dcc_get_put_ops = {
 88	.get_chars = hvc_dcc_get_chars,
 89	.put_chars = hvc_dcc_put_chars,
 90};
 91
 92static int __init hvc_dcc_console_init(void)
 93{
 94	hvc_instantiate(0, 0, &hvc_dcc_get_put_ops);
 95	return 0;
 96}
 97console_initcall(hvc_dcc_console_init);
 98
 99static int __init hvc_dcc_init(void)
100{
101	hvc_alloc(0, 0, &hvc_dcc_get_put_ops, 128);
102	return 0;
103}
104device_initcall(hvc_dcc_init);

  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
 33static inline u32 __dcc_getstatus(void)
 34{
 35	u32 __ret;
 36	asm volatile("mrc p14, 0, %0, c0, c1, 0	@ read comms ctrl reg"
 37		: "=r" (__ret) : : "cc");
 38
 39	return __ret;
 40}
 41
 42
 43static inline char __dcc_getchar(void)
 44{
 45	char __c;
 46
 47	asm volatile("mrc p14, 0, %0, c0, c5, 0	@ read comms data reg"
 48		: "=r" (__c));
 49	isb();
 50
 51	return __c;
 52}
 53
 54static inline void __dcc_putchar(char c)
 55{
 56	asm volatile("mcr p14, 0, %0, c0, c5, 0	@ write a char"
 57		: /* no output register */
 58		: "r" (c));
 59	isb();
 60}
 61
 62static 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
 70		__dcc_putchar(buf[i]);
 71	}
 72
 73	return count;
 74}
 75
 76static int hvc_dcc_get_chars(uint32_t vt, char *buf, int count)
 77{
 78	int i;
 79
 80	for (i = 0; i < count; ++i)
 81		if (__dcc_getstatus() & DCC_STATUS_RX)
 82			buf[i] = __dcc_getchar();
 83		else
 84			break;
 85
 86	return i;
 87}
 88
 89static 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
 94static int __init hvc_dcc_console_init(void)
 95{
 96	hvc_instantiate(0, 0, &hvc_dcc_get_put_ops);
 97	return 0;
 98}
 99console_initcall(hvc_dcc_console_init);
100
101static int __init hvc_dcc_init(void)
102{
103	hvc_alloc(0, 0, &hvc_dcc_get_put_ops, 128);
104	return 0;
105}
106device_initcall(hvc_dcc_init);