1// SPDX-License-Identifier: GPL-2.0
2/*
3 * /dev/lcd driver for Apple Network Servers.
4 */
5
6#include <linux/types.h>
7#include <linux/errno.h>
8#include <linux/kernel.h>
9#include <linux/miscdevice.h>
10#include <linux/fcntl.h>
11#include <linux/module.h>
12#include <linux/delay.h>
13#include <linux/fs.h>
14#include <linux/of.h>
15
16#include <linux/uaccess.h>
17#include <asm/sections.h>
18#include <asm/io.h>
19
20#include "ans-lcd.h"
21
22#define ANSLCD_ADDR		0xf301c000
23#define ANSLCD_CTRL_IX 0x00
24#define ANSLCD_DATA_IX 0x10
25
26static unsigned long anslcd_short_delay = 80;
27static unsigned long anslcd_long_delay = 3280;
28static volatile unsigned char __iomem *anslcd_ptr;
29static DEFINE_MUTEX(anslcd_mutex);
30
31#undef DEBUG
32
33static void
34anslcd_write_byte_ctrl ( unsigned char c )
35{
36#ifdef DEBUG
37	printk(KERN_DEBUG "LCD: CTRL byte: %02x\n",c);
38#endif
39	out_8(anslcd_ptr + ANSLCD_CTRL_IX, c);
40	switch(c) {
41		case 1:
42		case 2:
43		case 3:
44			udelay(anslcd_long_delay); break;
45		default: udelay(anslcd_short_delay);
46	}
47}
48
49static void
50anslcd_write_byte_data ( unsigned char c )
51{
52	out_8(anslcd_ptr + ANSLCD_DATA_IX, c);
53	udelay(anslcd_short_delay);
54}
55
56static ssize_t
57anslcd_write( struct file * file, const char __user * buf,
58				size_t count, loff_t *ppos )
59{
60	const char __user *p = buf;
61	int i;
62
63#ifdef DEBUG
64	printk(KERN_DEBUG "LCD: write\n");
65#endif
66
67	if (!access_ok(buf, count))
68		return -EFAULT;
69
70	mutex_lock(&anslcd_mutex);
71	for ( i = *ppos; count > 0; ++i, ++p, --count )
72	{
73		char c;
74		__get_user(c, p);
75		anslcd_write_byte_data( c );
76	}
77	mutex_unlock(&anslcd_mutex);
78	*ppos = i;
79	return p - buf;
80}
81
82static long
83anslcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
84{
85	char ch, __user *temp;
86	long ret = 0;
87
88#ifdef DEBUG
89	printk(KERN_DEBUG "LCD: ioctl(%d,%d)\n",cmd,arg);
90#endif
91
92	mutex_lock(&anslcd_mutex);
93
94	switch ( cmd )
95	{
96	case ANSLCD_CLEAR:
97		anslcd_write_byte_ctrl ( 0x38 );
98		anslcd_write_byte_ctrl ( 0x0f );
99		anslcd_write_byte_ctrl ( 0x06 );
100		anslcd_write_byte_ctrl ( 0x01 );
101		anslcd_write_byte_ctrl ( 0x02 );
102		break;
103	case ANSLCD_SENDCTRL:
104		temp = (char __user *) arg;
105		__get_user(ch, temp);
106		for (; ch; temp++) { /* FIXME: This is ugly, but should work, as a \0 byte is not a valid command code */
107			anslcd_write_byte_ctrl ( ch );
108			__get_user(ch, temp);
109		}
110		break;
111	case ANSLCD_SETSHORTDELAY:
112		if (!capable(CAP_SYS_ADMIN))
113			ret =-EACCES;
114		else
115			anslcd_short_delay=arg;
116		break;
117	case ANSLCD_SETLONGDELAY:
118		if (!capable(CAP_SYS_ADMIN))
119			ret = -EACCES;
120		else
121			anslcd_long_delay=arg;
122		break;
123	default:
124		ret = -EINVAL;
125	}
126
127	mutex_unlock(&anslcd_mutex);
128	return ret;
129}
130
131static int
132anslcd_open( struct inode * inode, struct file * file )
133{
134	return 0;
135}
136
137const struct file_operations anslcd_fops = {
138	.write		= anslcd_write,
139	.unlocked_ioctl	= anslcd_ioctl,
140	.open		= anslcd_open,
141	.llseek		= default_llseek,
142};
143
144static struct miscdevice anslcd_dev = {
145	LCD_MINOR,
146	"anslcd",
147	&anslcd_fops
148};
149
150static const char anslcd_logo[] __initconst =
151				"********************"  /* Line #1 */
152				"*      LINUX!      *"  /* Line #3 */
153				"*    Welcome to    *"  /* Line #2 */
154				"********************"; /* Line #4 */
155
156static int __init
157anslcd_init(void)
158{
159	int a;
160	int retval;
161	struct device_node* node;
162
163	node = of_find_node_by_name(NULL, "lcd");
164	if (!node || !of_node_name_eq(node->parent, "gc")) {
165		of_node_put(node);
166		return -ENODEV;
167	}
168	of_node_put(node);
169
170	anslcd_ptr = ioremap(ANSLCD_ADDR, 0x20);
171
172	retval = misc_register(&anslcd_dev);
173	if(retval < 0){
174		printk(KERN_INFO "LCD: misc_register failed\n");
175		iounmap(anslcd_ptr);
176		return retval;
177	}
178
179#ifdef DEBUG
180	printk(KERN_DEBUG "LCD: init\n");
181#endif
182
183	mutex_lock(&anslcd_mutex);
184	anslcd_write_byte_ctrl ( 0x38 );
185	anslcd_write_byte_ctrl ( 0x0c );
186	anslcd_write_byte_ctrl ( 0x06 );
187	anslcd_write_byte_ctrl ( 0x01 );
188	anslcd_write_byte_ctrl ( 0x02 );
189	for(a=0;a<80;a++) {
190		anslcd_write_byte_data(anslcd_logo[a]);
191	}
192	mutex_unlock(&anslcd_mutex);
193	return 0;
194}
195
196static void __exit
197anslcd_exit(void)
198{
199	misc_deregister(&anslcd_dev);
200	iounmap(anslcd_ptr);
201}
202
203module_init(anslcd_init);
204module_exit(anslcd_exit);
205MODULE_LICENSE("GPL v2");
206