1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * I/O Processor (IOP) ADB Driver
4  * Written and (C) 1999 by Joshua M. Thompson (funaho@jurai.org)
5  * Based on via-cuda.c by Paul Mackerras.
6  *
7  * 1999-07-01 (jmt) - First implementation for new driver architecture.
8  *
9  * 1999-07-31 (jmt) - First working version.
10  */
11 
12 #include <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/mm.h>
15 #include <linux/delay.h>
16 #include <linux/init.h>
17 
18 #include <asm/macintosh.h>
19 #include <asm/macints.h>
20 #include <asm/mac_iop.h>
21 #include <asm/adb_iop.h>
22 #include <asm/unaligned.h>
23 
24 #include <linux/adb.h>
25 
26 static struct adb_request *current_req;
27 static struct adb_request *last_req;
28 static unsigned int autopoll_devs;
29 static u8 autopoll_addr;
30 
31 static enum adb_iop_state {
32 	idle,
33 	sending,
34 	awaiting_reply
35 } adb_iop_state;
36 
37 static void adb_iop_start(void);
38 static int adb_iop_probe(void);
39 static int adb_iop_init(void);
40 static int adb_iop_send_request(struct adb_request *, int);
41 static int adb_iop_write(struct adb_request *);
42 static int adb_iop_autopoll(int);
43 static void adb_iop_poll(void);
44 static int adb_iop_reset_bus(void);
45 
46 /* ADB command byte structure */
47 #define ADDR_MASK       0xF0
48 #define OP_MASK         0x0C
49 #define TALK            0x0C
50 
51 struct adb_driver adb_iop_driver = {
52 	.name         = "ISM IOP",
53 	.probe        = adb_iop_probe,
54 	.init         = adb_iop_init,
55 	.send_request = adb_iop_send_request,
56 	.autopoll     = adb_iop_autopoll,
57 	.poll         = adb_iop_poll,
58 	.reset_bus    = adb_iop_reset_bus
59 };
60 
adb_iop_done(void)61 static void adb_iop_done(void)
62 {
63 	struct adb_request *req = current_req;
64 
65 	adb_iop_state = idle;
66 
67 	req->complete = 1;
68 	current_req = req->next;
69 	if (req->done)
70 		(*req->done)(req);
71 
72 	if (adb_iop_state == idle)
73 		adb_iop_start();
74 }
75 
76 /*
77  * Completion routine for ADB commands sent to the IOP.
78  *
79  * This will be called when a packet has been successfully sent.
80  */
81 
adb_iop_complete(struct iop_msg * msg)82 static void adb_iop_complete(struct iop_msg *msg)
83 {
84 	unsigned long flags;
85 
86 	local_irq_save(flags);
87 
88 	adb_iop_state = awaiting_reply;
89 
90 	local_irq_restore(flags);
91 }
92 
93 /*
94  * Listen for ADB messages from the IOP.
95  *
96  * This will be called when unsolicited IOP messages are received.
97  * These IOP messages can carry ADB autopoll responses and also occur
98  * after explicit ADB commands.
99  */
100 
adb_iop_listen(struct iop_msg * msg)101 static void adb_iop_listen(struct iop_msg *msg)
102 {
103 	struct adb_iopmsg *amsg = (struct adb_iopmsg *)msg->message;
104 	u8 addr = (amsg->cmd & ADDR_MASK) >> 4;
105 	u8 op = amsg->cmd & OP_MASK;
106 	unsigned long flags;
107 	bool req_done = false;
108 
109 	local_irq_save(flags);
110 
111 	/* Responses to Talk commands may be unsolicited as they are
112 	 * produced when the IOP polls devices. They are mostly timeouts.
113 	 */
114 	if (op == TALK && ((1 << addr) & autopoll_devs))
115 		autopoll_addr = addr;
116 
117 	switch (amsg->flags & (ADB_IOP_EXPLICIT |
118 			       ADB_IOP_AUTOPOLL |
119 			       ADB_IOP_TIMEOUT)) {
120 	case ADB_IOP_EXPLICIT:
121 	case ADB_IOP_EXPLICIT | ADB_IOP_TIMEOUT:
122 		if (adb_iop_state == awaiting_reply) {
123 			struct adb_request *req = current_req;
124 
125 			if (req->reply_expected) {
126 				req->reply_len = amsg->count + 1;
127 				memcpy(req->reply, &amsg->cmd, req->reply_len);
128 			}
129 
130 			req_done = true;
131 		}
132 		break;
133 	case ADB_IOP_AUTOPOLL:
134 		if (((1 << addr) & autopoll_devs) &&
135 		    amsg->cmd == ADB_READREG(addr, 0))
136 			adb_input(&amsg->cmd, amsg->count + 1, 1);
137 		break;
138 	}
139 	msg->reply[0] = autopoll_addr ? ADB_IOP_AUTOPOLL : 0;
140 	msg->reply[1] = 0;
141 	msg->reply[2] = autopoll_addr ? ADB_READREG(autopoll_addr, 0) : 0;
142 	iop_complete_message(msg);
143 
144 	if (req_done)
145 		adb_iop_done();
146 
147 	local_irq_restore(flags);
148 }
149 
150 /*
151  * Start sending an ADB packet, IOP style
152  *
153  * There isn't much to do other than hand the packet over to the IOP
154  * after encapsulating it in an adb_iopmsg.
155  */
156 
adb_iop_start(void)157 static void adb_iop_start(void)
158 {
159 	struct adb_request *req;
160 	struct adb_iopmsg amsg;
161 
162 	/* get the packet to send */
163 	req = current_req;
164 	if (!req)
165 		return;
166 
167 	/* The IOP takes MacII-style packets, so strip the initial
168 	 * ADB_PACKET byte.
169 	 */
170 	amsg.flags = ADB_IOP_EXPLICIT;
171 	amsg.count = req->nbytes - 2;
172 
173 	/* amsg.data immediately follows amsg.cmd, effectively making
174 	 * &amsg.cmd a pointer to the beginning of a full ADB packet.
175 	 */
176 	memcpy(&amsg.cmd, req->data + 1, req->nbytes - 1);
177 
178 	req->sent = 1;
179 	adb_iop_state = sending;
180 
181 	/* Now send it. The IOP manager will call adb_iop_complete
182 	 * when the message has been sent.
183 	 */
184 	iop_send_message(ADB_IOP, ADB_CHAN, req, sizeof(amsg), (__u8 *)&amsg,
185 			 adb_iop_complete);
186 }
187 
adb_iop_probe(void)188 static int adb_iop_probe(void)
189 {
190 	if (!iop_ism_present)
191 		return -ENODEV;
192 	return 0;
193 }
194 
adb_iop_init(void)195 static int adb_iop_init(void)
196 {
197 	pr_info("adb: IOP ISM driver v0.4 for Unified ADB\n");
198 	iop_listen(ADB_IOP, ADB_CHAN, adb_iop_listen, "ADB");
199 	return 0;
200 }
201 
adb_iop_send_request(struct adb_request * req,int sync)202 static int adb_iop_send_request(struct adb_request *req, int sync)
203 {
204 	int err;
205 
206 	err = adb_iop_write(req);
207 	if (err)
208 		return err;
209 
210 	if (sync) {
211 		while (!req->complete)
212 			adb_iop_poll();
213 	}
214 	return 0;
215 }
216 
adb_iop_write(struct adb_request * req)217 static int adb_iop_write(struct adb_request *req)
218 {
219 	unsigned long flags;
220 
221 	if ((req->nbytes < 2) || (req->data[0] != ADB_PACKET)) {
222 		req->complete = 1;
223 		return -EINVAL;
224 	}
225 
226 	req->next = NULL;
227 	req->sent = 0;
228 	req->complete = 0;
229 	req->reply_len = 0;
230 
231 	local_irq_save(flags);
232 
233 	if (current_req) {
234 		last_req->next = req;
235 		last_req = req;
236 	} else {
237 		current_req = req;
238 		last_req = req;
239 	}
240 
241 	if (adb_iop_state == idle)
242 		adb_iop_start();
243 
244 	local_irq_restore(flags);
245 
246 	return 0;
247 }
248 
adb_iop_set_ap_complete(struct iop_msg * msg)249 static void adb_iop_set_ap_complete(struct iop_msg *msg)
250 {
251 	struct adb_iopmsg *amsg = (struct adb_iopmsg *)msg->message;
252 
253 	autopoll_devs = get_unaligned_be16(amsg->data);
254 	if (autopoll_devs & (1 << autopoll_addr))
255 		return;
256 	autopoll_addr = autopoll_devs ? (ffs(autopoll_devs) - 1) : 0;
257 }
258 
adb_iop_autopoll(int devs)259 static int adb_iop_autopoll(int devs)
260 {
261 	struct adb_iopmsg amsg;
262 	unsigned long flags;
263 	unsigned int mask = (unsigned int)devs & 0xFFFE;
264 
265 	local_irq_save(flags);
266 
267 	amsg.flags = ADB_IOP_SET_AUTOPOLL | (mask ? ADB_IOP_AUTOPOLL : 0);
268 	amsg.count = 2;
269 	amsg.cmd = 0;
270 	put_unaligned_be16(mask, amsg.data);
271 
272 	iop_send_message(ADB_IOP, ADB_CHAN, NULL, sizeof(amsg), (__u8 *)&amsg,
273 			 adb_iop_set_ap_complete);
274 
275 	local_irq_restore(flags);
276 
277 	return 0;
278 }
279 
adb_iop_poll(void)280 static void adb_iop_poll(void)
281 {
282 	iop_ism_irq_poll(ADB_IOP);
283 }
284 
adb_iop_reset_bus(void)285 static int adb_iop_reset_bus(void)
286 {
287 	struct adb_request req;
288 
289 	/* Command = 0, Address = ignored */
290 	adb_request(&req, NULL, ADBREQ_NOSEND, 1, ADB_BUSRESET);
291 	adb_iop_send_request(&req, 1);
292 
293 	/* Don't want any more requests during the Global Reset low time. */
294 	mdelay(3);
295 
296 	return 0;
297 }
298