1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Driver for the ADB controller in the Mac I/O (Hydra) chip.
4 */
5#include <linux/types.h>
6#include <linux/errno.h>
7#include <linux/kernel.h>
8#include <linux/delay.h>
9#include <linux/spinlock.h>
10#include <linux/interrupt.h>
11#include <linux/pgtable.h>
12#include <linux/of.h>
13#include <linux/of_address.h>
14#include <linux/of_irq.h>
15#include <linux/adb.h>
16
17#include <asm/io.h>
18#include <asm/hydra.h>
19#include <asm/irq.h>
20#include <linux/init.h>
21#include <linux/ioport.h>
22
23struct preg {
24	unsigned char r;
25	char pad[15];
26};
27
28struct adb_regs {
29	struct preg intr;
30	struct preg data[9];
31	struct preg intr_enb;
32	struct preg dcount;
33	struct preg error;
34	struct preg ctrl;
35	struct preg autopoll;
36	struct preg active_hi;
37	struct preg active_lo;
38	struct preg test;
39};
40
41/* Bits in intr and intr_enb registers */
42#define DFB	1		/* data from bus */
43#define TAG	2		/* transfer access grant */
44
45/* Bits in dcount register */
46#define HMB	0x0f		/* how many bytes */
47#define APD	0x10		/* auto-poll data */
48
49/* Bits in error register */
50#define NRE	1		/* no response error */
51#define DLE	2		/* data lost error */
52
53/* Bits in ctrl register */
54#define TAR	1		/* transfer access request */
55#define DTB	2		/* data to bus */
56#define CRE	4		/* command response expected */
57#define ADB_RST	8		/* ADB reset */
58
59/* Bits in autopoll register */
60#define APE	1		/* autopoll enable */
61
62static volatile struct adb_regs __iomem *adb;
63static struct adb_request *current_req, *last_req;
64static DEFINE_SPINLOCK(macio_lock);
65
66static int macio_probe(void);
67static int macio_init(void);
68static irqreturn_t macio_adb_interrupt(int irq, void *arg);
69static int macio_send_request(struct adb_request *req, int sync);
70static int macio_adb_autopoll(int devs);
71static void macio_adb_poll(void);
72static int macio_adb_reset_bus(void);
73
74struct adb_driver macio_adb_driver = {
75	.name         = "MACIO",
76	.probe        = macio_probe,
77	.init         = macio_init,
78	.send_request = macio_send_request,
79	.autopoll     = macio_adb_autopoll,
80	.poll         = macio_adb_poll,
81	.reset_bus    = macio_adb_reset_bus,
82};
83
84int macio_probe(void)
85{
86	struct device_node *np;
87
88	np = of_find_compatible_node(NULL, "adb", "chrp,adb0");
89	if (np) {
90		of_node_put(np);
91		return 0;
92	}
93	return -ENODEV;
94}
95
96int macio_init(void)
97{
98	struct device_node *adbs;
99	struct resource r;
100	unsigned int irq;
101
102	adbs = of_find_compatible_node(NULL, "adb", "chrp,adb0");
103	if (!adbs)
104		return -ENXIO;
105
106	if (of_address_to_resource(adbs, 0, &r)) {
107		of_node_put(adbs);
108		return -ENXIO;
109	}
110	adb = ioremap(r.start, sizeof(struct adb_regs));
111	if (!adb) {
112		of_node_put(adbs);
113		return -ENOMEM;
114	}
115
116	out_8(&adb->ctrl.r, 0);
117	out_8(&adb->intr.r, 0);
118	out_8(&adb->error.r, 0);
119	out_8(&adb->active_hi.r, 0xff); /* for now, set all devices active */
120	out_8(&adb->active_lo.r, 0xff);
121	out_8(&adb->autopoll.r, APE);
122
123	irq = irq_of_parse_and_map(adbs, 0);
124	of_node_put(adbs);
125	if (request_irq(irq, macio_adb_interrupt, 0, "ADB", (void *)0)) {
126		printk(KERN_ERR "ADB: can't get irq %d\n", irq);
127		return -EAGAIN;
128	}
129	out_8(&adb->intr_enb.r, DFB | TAG);
130
131	printk("adb: mac-io driver 1.0 for unified ADB\n");
132
133	return 0;
134}
135
136static int macio_adb_autopoll(int devs)
137{
138	unsigned long flags;
139
140	spin_lock_irqsave(&macio_lock, flags);
141	out_8(&adb->active_hi.r, devs >> 8);
142	out_8(&adb->active_lo.r, devs);
143	out_8(&adb->autopoll.r, devs? APE: 0);
144	spin_unlock_irqrestore(&macio_lock, flags);
145	return 0;
146}
147
148static int macio_adb_reset_bus(void)
149{
150	unsigned long flags;
151	int timeout = 1000000;
152
153	/* Hrm... we may want to not lock interrupts for so
154	 * long ... oh well, who uses that chip anyway ? :)
155	 * That function will be seldom used during boot
156	 * on rare machines, so...
157	 */
158	spin_lock_irqsave(&macio_lock, flags);
159	out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | ADB_RST);
160	while ((in_8(&adb->ctrl.r) & ADB_RST) != 0) {
161		if (--timeout == 0) {
162			out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) & ~ADB_RST);
163			spin_unlock_irqrestore(&macio_lock, flags);
164			return -1;
165		}
166	}
167	spin_unlock_irqrestore(&macio_lock, flags);
168	return 0;
169}
170
171/* Send an ADB command */
172static int macio_send_request(struct adb_request *req, int sync)
173{
174	unsigned long flags;
175	int i;
176
177	if (req->data[0] != ADB_PACKET)
178		return -EINVAL;
179
180	for (i = 0; i < req->nbytes - 1; ++i)
181		req->data[i] = req->data[i+1];
182	--req->nbytes;
183
184	req->next = NULL;
185	req->sent = 0;
186	req->complete = 0;
187	req->reply_len = 0;
188
189	spin_lock_irqsave(&macio_lock, flags);
190	if (current_req) {
191		last_req->next = req;
192		last_req = req;
193	} else {
194		current_req = last_req = req;
195		out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
196	}
197	spin_unlock_irqrestore(&macio_lock, flags);
198
199	if (sync) {
200		while (!req->complete)
201			macio_adb_poll();
202	}
203
204	return 0;
205}
206
207static irqreturn_t macio_adb_interrupt(int irq, void *arg)
208{
209	int i, n, err;
210	struct adb_request *req = NULL;
211	unsigned char ibuf[16];
212	int ibuf_len = 0;
213	int complete = 0;
214	int autopoll = 0;
215	int handled = 0;
216
217	spin_lock(&macio_lock);
218	if (in_8(&adb->intr.r) & TAG) {
219		handled = 1;
220		req = current_req;
221		if (req) {
222			/* put the current request in */
223			for (i = 0; i < req->nbytes; ++i)
224				out_8(&adb->data[i].r, req->data[i]);
225			out_8(&adb->dcount.r, req->nbytes & HMB);
226			req->sent = 1;
227			if (req->reply_expected) {
228				out_8(&adb->ctrl.r, DTB + CRE);
229			} else {
230				out_8(&adb->ctrl.r, DTB);
231				current_req = req->next;
232				complete = 1;
233				if (current_req)
234					out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
235			}
236		}
237		out_8(&adb->intr.r, 0);
238	}
239
240	if (in_8(&adb->intr.r) & DFB) {
241		handled = 1;
242		err = in_8(&adb->error.r);
243		if (current_req && current_req->sent) {
244			/* this is the response to a command */
245			req = current_req;
246			if (err == 0) {
247				req->reply_len = in_8(&adb->dcount.r) & HMB;
248				for (i = 0; i < req->reply_len; ++i)
249					req->reply[i] = in_8(&adb->data[i].r);
250			}
251			current_req = req->next;
252			complete = 1;
253			if (current_req)
254				out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
255		} else if (err == 0) {
256			/* autopoll data */
257			n = in_8(&adb->dcount.r) & HMB;
258			for (i = 0; i < n; ++i)
259				ibuf[i] = in_8(&adb->data[i].r);
260			ibuf_len = n;
261			autopoll = (in_8(&adb->dcount.r) & APD) != 0;
262		}
263		out_8(&adb->error.r, 0);
264		out_8(&adb->intr.r, 0);
265	}
266	spin_unlock(&macio_lock);
267	if (complete && req) {
268	    void (*done)(struct adb_request *) = req->done;
269	    mb();
270	    req->complete = 1;
271	    /* Here, we assume that if the request has a done member, the
272    	     * struct request will survive to setting req->complete to 1
273	     */
274	    if (done)
275		(*done)(req);
276	}
277	if (ibuf_len)
278		adb_input(ibuf, ibuf_len, autopoll);
279
280	return IRQ_RETVAL(handled);
281}
282
283static void macio_adb_poll(void)
284{
285	unsigned long flags;
286
287	local_irq_save(flags);
288	if (in_8(&adb->intr.r) != 0)
289		macio_adb_interrupt(0, NULL);
290	local_irq_restore(flags);
291}
292