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
26static struct adb_request *current_req;
27static struct adb_request *last_req;
28static unsigned int autopoll_devs;
29static u8 autopoll_addr;
30
31static enum adb_iop_state {
32	idle,
33	sending,
34	awaiting_reply
35} adb_iop_state;
36
37static void adb_iop_start(void);
38static int adb_iop_probe(void);
39static int adb_iop_init(void);
40static int adb_iop_send_request(struct adb_request *, int);
41static int adb_iop_write(struct adb_request *);
42static int adb_iop_autopoll(int);
43static void adb_iop_poll(void);
44static 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
51struct 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
61static 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
82static 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
101static 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
157static 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
188static int adb_iop_probe(void)
189{
190	if (!iop_ism_present)
191		return -ENODEV;
192	return 0;
193}
194
195static 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
202static 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
217static 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
249static 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
259static 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
280static void adb_iop_poll(void)
281{
282	iop_ism_irq_poll(ADB_IOP);
283}
284
285static 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