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 
26 static unsigned long anslcd_short_delay = 80;
27 static unsigned long anslcd_long_delay = 3280;
28 static volatile unsigned char __iomem *anslcd_ptr;
29 static DEFINE_MUTEX(anslcd_mutex);
30 
31 #undef DEBUG
32 
33 static void
anslcd_write_byte_ctrl(unsigned char c)34 anslcd_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 
49 static void
anslcd_write_byte_data(unsigned char c)50 anslcd_write_byte_data ( unsigned char c )
51 {
52 	out_8(anslcd_ptr + ANSLCD_DATA_IX, c);
53 	udelay(anslcd_short_delay);
54 }
55 
56 static ssize_t
anslcd_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)57 anslcd_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 
82 static long
anslcd_ioctl(struct file * file,unsigned int cmd,unsigned long arg)83 anslcd_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 
131 static int
anslcd_open(struct inode * inode,struct file * file)132 anslcd_open( struct inode * inode, struct file * file )
133 {
134 	return 0;
135 }
136 
137 const struct file_operations anslcd_fops = {
138 	.write		= anslcd_write,
139 	.unlocked_ioctl	= anslcd_ioctl,
140 	.open		= anslcd_open,
141 	.llseek		= default_llseek,
142 };
143 
144 static struct miscdevice anslcd_dev = {
145 	LCD_MINOR,
146 	"anslcd",
147 	&anslcd_fops
148 };
149 
150 static const char anslcd_logo[] __initconst =
151 				"********************"  /* Line #1 */
152 				"*      LINUX!      *"  /* Line #3 */
153 				"*    Welcome to    *"  /* Line #2 */
154 				"********************"; /* Line #4 */
155 
156 static int __init
anslcd_init(void)157 anslcd_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 
196 static void __exit
anslcd_exit(void)197 anslcd_exit(void)
198 {
199 	misc_deregister(&anslcd_dev);
200 	iounmap(anslcd_ptr);
201 }
202 
203 module_init(anslcd_init);
204 module_exit(anslcd_exit);
205 MODULE_LICENSE("GPL v2");
206