xref: /openbmc/linux/drivers/ata/pata_parport/comm.c (revision 6de298ff)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * (c) 1997-1998  Grant R. Guenther <grant@torque.net>
4  *
5  * comm.c is a low-level protocol driver for some older models of the DataStor
6  * "Commuter" parallel to IDE adapter. Some of the parallel port devices
7  * marketed by Arista currently use this adapter.
8  */
9 
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/delay.h>
13 #include <linux/kernel.h>
14 #include <linux/types.h>
15 #include <linux/wait.h>
16 #include <asm/io.h>
17 #include "pata_parport.h"
18 
19 /*
20  * mode codes:  0  nybble reads, 8-bit writes
21  *              1  8-bit reads and writes
22  *              2  8-bit EPP mode
23  */
24 
25 #define j44(a, b)	(((a >> 3) & 0x0f) | ((b << 1) & 0xf0))
26 
27 #define P1	w2(5);w2(0xd);w2(0xd);w2(5);w2(4);
28 #define P2	w2(5);w2(7);w2(7);w2(5);w2(4);
29 
30 /*
31  * cont = 0 - access the IDE register file
32  * cont = 1 - access the IDE command set
33  */
34 static int  cont_map[2] = { 0x08, 0x10 };
35 
36 static int comm_read_regr(struct pi_adapter *pi, int cont, int regr)
37 {
38 	int l, h, r;
39 
40         r = regr + cont_map[cont];
41 
42 	switch (pi->mode) {
43 	case 0:
44 		w0(r); P1; w0(0);
45 		w2(6); l = r1(); w0(0x80); h = r1(); w2(4);
46 		return j44(l, h);
47 
48 	case 1:
49 		w0(r+0x20); P1;
50 		w0(0); w2(0x26); h = r0(); w2(4);
51 		return h;
52 
53 	case 2:
54 	case 3:
55 	case 4:
56 		w3(r+0x20); (void)r1();
57 		w2(0x24); h = r4(); w2(4);
58 		return h;
59 	}
60 
61 	return -1;
62 }
63 
64 static void comm_write_regr(struct pi_adapter *pi, int cont, int regr, int val)
65 {
66 	int r = regr + cont_map[cont];
67 
68 	switch (pi->mode) {
69 	case 0:
70 	case 1:
71 		w0(r); P1; w0(val); P2;
72 		break;
73 	case 2:
74 	case 3:
75 	case 4:
76 		w3(r); (void)r1(); w4(val);
77 		break;
78 	}
79 }
80 
81 static void comm_connect(struct pi_adapter *pi)
82 {
83 	pi->saved_r0 = r0();
84 	pi->saved_r2 = r2();
85 	w2(4); w0(0xff); w2(6);
86 	w2(4); w0(0xaa); w2(6);
87 	w2(4); w0(0x00); w2(6);
88 	w2(4); w0(0x87); w2(6);
89 	w2(4); w0(0xe0); w2(0xc); w2(0xc); w2(4);
90 }
91 
92 static void comm_disconnect(struct pi_adapter *pi)
93 
94 {
95 	w2(0); w2(0); w2(0); w2(4);
96 	w0(pi->saved_r0);
97 	w2(pi->saved_r2);
98 }
99 
100 static void comm_read_block(struct pi_adapter *pi, char *buf, int count)
101 {
102 	int i, l, h;
103 
104 	switch (pi->mode) {
105 	case 0:
106 		w0(0x48); P1;
107 		for (i = 0; i < count; i++) {
108 			w0(0); w2(6); l = r1();
109 			w0(0x80); h = r1(); w2(4);
110 			buf[i] = j44(l, h);
111 		}
112 		break;
113 	case 1:
114 		w0(0x68); P1; w0(0);
115 		for (i = 0; i < count; i++) {
116 			w2(0x26);
117 			buf[i] = r0();
118 			w2(0x24);
119 		}
120 		w2(4);
121 		break;
122 	case 2:
123 		w3(0x68); (void)r1(); w2(0x24);
124 		for (i = 0; i < count; i++)
125 			buf[i] = r4();
126 		w2(4);
127 		break;
128 	case 3:
129 		w3(0x68); (void)r1(); w2(0x24);
130 		for (i = 0; i < count / 2; i++)
131 			((u16 *)buf)[i] = r4w();
132 		w2(4);
133 		break;
134 	case 4:
135 		w3(0x68); (void)r1(); w2(0x24);
136 		for (i = 0; i < count / 4; i++)
137 			((u32 *)buf)[i] = r4l();
138 		w2(4);
139 		break;
140 	}
141 }
142 
143 /* NB: Watch out for the byte swapped writes ! */
144 static void comm_write_block(struct pi_adapter *pi, char *buf, int count)
145 {
146 	int k;
147 
148 	switch (pi->mode) {
149 	case 0:
150 	case 1:
151 		w0(0x68); P1;
152 		for (k = 0; k < count; k++) {
153 			w2(5);
154 			w0(buf[k ^ 1]);
155 			w2(7);
156 		}
157 		w2(5); w2(4);
158 		break;
159 	case 2:
160 		w3(0x48); (void)r1();
161 		for (k = 0; k < count; k++)
162 			w4(buf[k ^ 1]);
163 		break;
164 	case 3:
165 		w3(0x48); (void)r1();
166 		for (k = 0; k < count / 2; k++)
167 			w4w(swab16(((u16 *)buf)[k]));
168 		break;
169 	case 4:
170 		w3(0x48); (void)r1();
171 		for (k = 0; k < count / 4; k++)
172 			w4l(swab16(((u16 *)buf)[2 * k]) |
173 			    swab16(((u16 *)buf)[2 * k + 1]) << 16);
174 		break;
175         }
176 }
177 
178 static void comm_log_adapter(struct pi_adapter *pi)
179 
180 {       char *mode_string[5] = { "4-bit", "8-bit", "EPP-8", "EPP-16", "EPP-32" };
181 
182 	dev_info(&pi->dev,
183 		 "DataStor Commuter at 0x%x, mode %d (%s), delay %d\n",
184 		 pi->port, pi->mode, mode_string[pi->mode], pi->delay);
185 }
186 
187 static struct pi_protocol comm = {
188 	.owner		= THIS_MODULE,
189 	.name		= "comm",
190 	.max_mode	= 5,
191 	.epp_first	= 2,
192 	.default_delay	= 1,
193 	.max_units	= 1,
194 	.write_regr	= comm_write_regr,
195 	.read_regr	= comm_read_regr,
196 	.write_block	= comm_write_block,
197 	.read_block	= comm_read_block,
198 	.connect	= comm_connect,
199 	.disconnect	= comm_disconnect,
200 	.log_adapter	= comm_log_adapter,
201 };
202 
203 MODULE_LICENSE("GPL");
204 module_pata_parport_driver(comm);
205