xref: /openbmc/linux/drivers/ata/pata_parport/epia.c (revision f7875966)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * (c) 1997-1998  Grant R. Guenther <grant@torque.net>
4  *
5  * epia.c is a low-level protocol driver for Shuttle Technologies
6  * EPIA parallel to IDE adapter chip.  This device is now obsolete
7  * and has been replaced with the EPAT chip, which is supported
8  * by epat.c, however, some devices based on EPIA are still
9  * available.
10  */
11 
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/delay.h>
15 #include <linux/kernel.h>
16 #include <linux/types.h>
17 #include <linux/wait.h>
18 #include <asm/io.h>
19 #include "pata_parport.h"
20 
21 /*
22  * mode codes:  0  nybble reads on port 1, 8-bit writes
23  *		1  5/3 reads on ports 1 & 2, 8-bit writes
24  *		2  8-bit reads and writes
25  *		3  8-bit EPP mode
26  *		4  16-bit EPP
27  *		5  32-bit EPP
28  */
29 
30 #define j44(a, b)	(((a >> 4) & 0x0f) + (b & 0xf0))
31 #define j53(a, b)	(((a >> 3) & 0x1f) + ((b << 4) & 0xe0))
32 
33 /*
34  * cont =  0   IDE register file
35  * cont =  1   IDE control registers
36  */
37 static int cont_map[2] = { 0, 0x80 };
38 
39 static int epia_read_regr(struct pi_adapter *pi, int cont, int regr)
40 {
41 	int a, b, r;
42 
43 	regr += cont_map[cont];
44 
45 	switch (pi->mode)  {
46 	case 0:
47 		r = regr ^ 0x39;
48 		w0(r); w2(1); w2(3); w0(r);
49 		a = r1(); w2(1); b = r1(); w2(4);
50 		return j44(a, b);
51 	case 1:
52 		r = regr ^ 0x31;
53 		w0(r); w2(1); w0(r & 0x37);
54 		w2(3); w2(5); w0(r | 0xf0);
55 		a = r1(); b = r2(); w2(4);
56 		return j53(a, b);
57 	case 2:
58 		r = regr^0x29;
59 		w0(r); w2(1); w2(0X21); w2(0x23);
60 		a = r0(); w2(4);
61 		return a;
62 	case 3:
63 	case 4:
64 	case 5:
65 		w3(regr); w2(0x24); a = r4(); w2(4);
66 		return a;
67 	}
68 
69 	return -1;
70 }
71 
72 static void epia_write_regr(struct pi_adapter *pi, int cont, int regr, int val)
73 {
74 	int  r;
75 
76 	regr += cont_map[cont];
77 
78 	switch (pi->mode)  {
79 	case 0:
80 	case 1:
81 	case 2:
82 		r = regr ^ 0x19;
83 		w0(r); w2(1); w0(val); w2(3); w2(4);
84 		break;
85 	case 3:
86 	case 4:
87 	case 5:
88 		r = regr ^ 0x40;
89 		w3(r); w4(val); w2(4);
90 		break;
91 	}
92 }
93 
94 #define WR(r, v)	epia_write_regr(pi, 0, r, v)
95 #define RR(r)		epia_read_regr(pi, 0, r)
96 
97 /*
98  * The use of register 0x84 is entirely unclear - it seems to control
99  * some EPP counters ...  currently we know about 3 different block
100  * sizes:  the standard 512 byte reads and writes, 12 byte writes and
101  * 2048 byte reads (the last two being used in the CDrom drivers.
102  */
103 static void epia_connect(struct pi_adapter *pi)
104 {
105 	pi->saved_r0 = r0();
106 	pi->saved_r2 = r2();
107 
108 	w2(4); w0(0xa0); w0(0x50); w0(0xc0); w0(0x30); w0(0xa0); w0(0);
109 	w2(1); w2(4);
110 	if (pi->mode >= 3) {
111 		w0(0xa); w2(1); w2(4); w0(0x82); w2(4); w2(0xc); w2(4);
112 		w2(0x24); w2(0x26); w2(4);
113 	}
114 	WR(0x86, 8);
115 }
116 
117 static void epia_disconnect(struct pi_adapter *pi)
118 {
119 	/* WR(0x84,0x10); */
120 	w0(pi->saved_r0);
121 	w2(1); w2(4);
122 	w0(pi->saved_r0);
123 	w2(pi->saved_r2);
124 }
125 
126 static void epia_read_block(struct pi_adapter *pi, char *buf, int count)
127 
128 {
129 	int k, ph, a, b;
130 
131 	switch (pi->mode) {
132 	case 0:
133 		w0(0x81); w2(1); w2(3); w0(0xc1);
134 		ph = 1;
135 		for (k = 0; k < count; k++) {
136 			w2(2+ph); a = r1();
137 			w2(4+ph); b = r1();
138 			buf[k] = j44(a, b);
139 			ph = 1 - ph;
140 		}
141 		w0(0); w2(4);
142 		break;
143 	case 1:
144 		w0(0x91); w2(1); w0(0x10); w2(3);
145 		w0(0x51); w2(5); w0(0xd1);
146 		ph = 1;
147 		for (k = 0; k < count; k++) {
148 			w2(4 + ph);
149 			a = r1(); b = r2();
150 			buf[k] = j53(a, b);
151 			ph = 1 - ph;
152 		}
153 		w0(0); w2(4);
154 		break;
155 	case 2:
156 		w0(0x89); w2(1); w2(0x23); w2(0x21);
157 		ph = 1;
158 		for (k = 0; k < count; k++) {
159 			w2(0x24 + ph);
160 			buf[k] = r0();
161 			ph = 1 - ph;
162 		}
163 		w2(6); w2(4);
164 		break;
165 	case 3:
166 		if (count > 512)
167 			WR(0x84, 3);
168 		w3(0); w2(0x24);
169 		for (k = 0; k < count; k++)
170 			buf[k] = r4();
171 		w2(4); WR(0x84, 0);
172 		break;
173 	case 4:
174 		if (count > 512)
175 			WR(0x84, 3);
176 		w3(0); w2(0x24);
177 		for (k = 0; k < count / 2; k++)
178 			((u16 *)buf)[k] = r4w();
179 		w2(4); WR(0x84, 0);
180 		break;
181 	case 5:
182 		if (count > 512)
183 			WR(0x84, 3);
184 		w3(0); w2(0x24);
185 		for (k = 0; k < count / 4; k++)
186 			((u32 *)buf)[k] = r4l();
187 		w2(4); WR(0x84, 0);
188 		break;
189 	}
190 }
191 
192 static void epia_write_block(struct pi_adapter *pi, char *buf, int count)
193 {
194 	int ph, k, last, d;
195 
196 	switch (pi->mode) {
197 	case 0:
198 	case 1:
199 	case 2:
200 		w0(0xa1); w2(1); w2(3); w2(1); w2(5);
201 		ph = 0;  last = 0x8000;
202 		for (k = 0; k < count; k++) {
203 			d = buf[k];
204 			if (d != last) {
205 				last = d;
206 				w0(d);
207 			}
208 			w2(4 + ph);
209 			ph = 1 - ph;
210 		}
211 		w2(7); w2(4);
212 		break;
213 	case 3:
214 		if (count < 512)
215 			WR(0x84, 1);
216 		w3(0x40);
217 		for (k = 0; k < count; k++)
218 			w4(buf[k]);
219 		if (count < 512)
220 			WR(0x84, 0);
221 		break;
222 	case 4:
223 		if (count < 512)
224 			WR(0x84, 1);
225 		w3(0x40);
226 		for (k = 0; k < count / 2; k++)
227 			w4w(((u16 *)buf)[k]);
228 		if (count < 512)
229 			WR(0x84, 0);
230 		break;
231 	case 5:
232 		if (count < 512)
233 			WR(0x84, 1);
234 		w3(0x40);
235 		for (k = 0; k < count / 4; k++)
236 			w4l(((u32 *)buf)[k]);
237 		if (count < 512)
238 			WR(0x84, 0);
239 		break;
240 	}
241 }
242 
243 static int epia_test_proto(struct pi_adapter *pi)
244 {
245 	int j, k, f;
246 	int e[2] = { 0, 0 };
247 	char scratch[512];
248 
249 	epia_connect(pi);
250 	for (j = 0; j < 2; j++) {
251 		WR(6, 0xa0 + j * 0x10);
252 		for (k = 0; k < 256; k++) {
253 			WR(2, k ^ 0xaa);
254 			WR(3, k ^ 0x55);
255 			if (RR(2) != (k ^ 0xaa))
256 				e[j]++;
257 		}
258 		WR(2, 1); WR(3, 1);
259 	}
260 	epia_disconnect(pi);
261 
262 	f = 0;
263 	epia_connect(pi);
264 	WR(0x84, 8);
265 	epia_read_block(pi, scratch, 512);
266 	for (k = 0; k < 256; k++) {
267 		if ((scratch[2 * k] & 0xff) != ((k + 1) & 0xff))
268 			f++;
269 		if ((scratch[2 * k + 1] & 0xff) != ((-2 - k) & 0xff))
270 			f++;
271 	}
272 	WR(0x84, 0);
273 	epia_disconnect(pi);
274 
275 	dev_dbg(&pi->dev, "epia: port 0x%x, mode %d, test=(%d,%d,%d)\n",
276 		pi->port, pi->mode, e[0], e[1], f);
277 
278 	return (e[0] && e[1]) || f;
279 }
280 
281 
282 static void epia_log_adapter(struct pi_adapter *pi)
283 {
284 	char *mode[6] = { "4-bit", "5/3", "8-bit", "EPP-8", "EPP-16", "EPP-32"};
285 
286 	dev_info(&pi->dev,
287 		 "Shuttle EPIA at 0x%x, mode %d (%s), delay %d\n",
288 		 pi->port, pi->mode, mode[pi->mode], pi->delay);
289 }
290 
291 static struct pi_protocol epia = {
292 	.owner		= THIS_MODULE,
293 	.name		= "epia",
294 	.max_mode	= 6,
295 	.epp_first	= 3,
296 	.default_delay	= 1,
297 	.max_units	= 1,
298 	.write_regr	= epia_write_regr,
299 	.read_regr	= epia_read_regr,
300 	.write_block	= epia_write_block,
301 	.read_block	= epia_read_block,
302 	.connect	= epia_connect,
303 	.disconnect	= epia_disconnect,
304 	.test_proto	= epia_test_proto,
305 	.log_adapter	= epia_log_adapter,
306 };
307 
308 MODULE_LICENSE("GPL");
309 MODULE_AUTHOR("Grant R. Guenther <grant@torque.net>");
310 MODULE_DESCRIPTION("Shuttle Technologies EPIA parallel port IDE adapter "
311 		   "protocol driver");
312 module_pata_parport_driver(epia);
313