1/* $NetBSD: gecko.c,v 1.1 2025/11/15 17:59:24 jmcneill Exp $ */
2
3/*-
4 * Copyright (c) 2025 Jared McNeill <jmcneill@invisible.ca>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/*
30 * Serial console support over USB Gecko.
31 */
32
33#include <sys/cdefs.h>
34
35__KERNEL_RCSID(0, "$NetBSD: gecko.c,v 1.1 2025/11/15 17:59:24 jmcneill Exp $");
36
37#include <sys/param.h>
38#include <sys/systm.h>
39#include <sys/bus.h>
40#include <sys/bitops.h>
41#include <sys/conf.h>
42#include <sys/device.h>
43#include <machine/pio.h>
44#include <machine/wii.h>
45
46#include <dev/cons.h>
47
48#include "exi.h"
49#include "exireg.h"
50#include "gecko.h"
51
52#define USBGECKO_CSR					\
53	(__SHIFTIN(1, EXI_CSR_CS) |			\
54	 __SHIFTIN(EXI_FREQ_32MHZ, EXI_CSR_CLK))
55#define USBGECKO_CR(len, rdwr)				\
56	(__SHIFTIN((len) - 1, EXI_CR_TLEN) | 		\
57	 (rdwr) | EXI_CR_TSTART)
58
59#define USBGECKO_CMD_LED_OFF	0x7000
60#define USBGECKO_CMD_LED_ON	0x8000
61#define USBGECKO_CMD_ID		0x9000
62#define USBGECKO_CMD_RECV_BYTE	0xa000
63#define USBGECKO_CMD_SEND_BYTE	0xb000
64
65
66#define RD4(reg)		in32(EXI_BASE + (reg))
67#define WR4(reg, val)		out32(EXI_BASE + (reg), val)
68
69static int	usbgecko_cngetc(dev_t);
70static void	usbgecko_cnputc(dev_t, int);
71static void	usbgecko_cnpollc(dev_t, int);
72
73static struct cnm_state usbgecko_cnmstate;
74static struct consdev usbgecko_consdev = {
75	.cn_getc = usbgecko_cngetc,
76	.cn_putc = usbgecko_cnputc,
77	.cn_pollc = usbgecko_cnpollc,
78	.cn_dev = NODEV,
79	.cn_pri = CN_NORMAL,
80};
81static uint32_t usbgecko_chan;
82static bool usbgecko_found;
83
84struct usbgecko_softc {
85	device_t	sc_dev;
86	uint8_t		sc_chan;
87	uint8_t		sc_device;
88};
89
90static struct usbgecko_softc *usbgecko_sc;
91
92static int	usbgecko_match(device_t, cfdata_t, void *);
93static void	usbgecko_attach(device_t, device_t, void *);
94
95CFATTACH_DECL_NEW(gecko, sizeof(struct usbgecko_softc),
96    usbgecko_match, usbgecko_attach, NULL, NULL);
97
98static void
99usbgecko_wait(void)
100{
101	int retry;
102
103	for (retry = 0; retry < 1000; retry++) {
104		if ((RD4(EXI_CR(usbgecko_chan)) & EXI_CR_TSTART) == 0) {
105			return;
106		}
107	}
108}
109
110static uint16_t
111usbgecko_command(uint16_t command)
112{
113	struct usbgecko_softc *sc = usbgecko_sc;
114	uint32_t command32 = (uint32_t)command << 16;
115	uint16_t value;
116
117	if (sc != NULL) {
118		exi_select(sc->sc_chan, sc->sc_device, EXI_FREQ_32MHZ);
119		exi_sendrecv_imm(sc->sc_chan, sc->sc_device, &command32,
120		    &value, sizeof(value));
121		exi_unselect(sc->sc_chan);
122	} else {
123		WR4(EXI_CSR(usbgecko_chan), USBGECKO_CSR);
124		WR4(EXI_DATA(usbgecko_chan), command32);
125		WR4(EXI_CR(usbgecko_chan), USBGECKO_CR(2, EXI_CR_RW_READWRITE));
126		usbgecko_wait();
127		value = RD4(EXI_DATA(usbgecko_chan)) >> 16;
128		WR4(EXI_CSR(usbgecko_chan), 0);
129	}
130
131	return value;
132}
133
134static uint32_t
135usbgecko_id(void)
136{
137	uint32_t value;
138
139	KASSERT(usbgecko_sc == NULL);
140
141	WR4(EXI_CSR(usbgecko_chan), USBGECKO_CSR);
142	WR4(EXI_DATA(usbgecko_chan), 0);
143	WR4(EXI_CR(usbgecko_chan), USBGECKO_CR(2, EXI_CR_RW_READWRITE));
144	usbgecko_wait();
145	WR4(EXI_CR(usbgecko_chan), USBGECKO_CR(sizeof(value),
146	    EXI_CR_RW_READWRITE));
147	usbgecko_wait();
148	value = RD4(EXI_DATA(usbgecko_chan));
149	WR4(EXI_CSR(usbgecko_chan), 0);
150
151	return value;
152}
153
154static int
155usbgecko_cngetc(dev_t dev)
156{
157	uint16_t value;
158
159	value = usbgecko_command(USBGECKO_CMD_RECV_BYTE);
160	return (value & 0x0800) == 0 ? -1 : (value & 0xff);
161}
162
163static void
164usbgecko_cnputc(dev_t dev, int c)
165{
166	c &= 0xff;
167	usbgecko_command(USBGECKO_CMD_SEND_BYTE | (c << 4));
168}
169
170static void
171usbgecko_cnpollc(dev_t dev, int on)
172{
173}
174
175static bool
176usbgecko_detect(void)
177{
178	return usbgecko_id() == 0 &&
179	       usbgecko_command(USBGECKO_CMD_ID) == 0x0470;
180}
181
182void
183usbgecko_consinit(void)
184{
185	WR4(EXI_CSR(0), 0);
186	WR4(EXI_CSR(1), 0);
187	WR4(EXI_CSR(2), 0);
188
189	WR4(EXI_CSR(0), EXI_CSR_EXTINT | EXI_CSR_EXTINTMASK);
190	WR4(EXI_CSR(1), EXI_CSR_EXTINT | EXI_CSR_EXTINTMASK);
191
192	usbgecko_chan = 0;
193	if (!usbgecko_detect()) {
194		usbgecko_chan = 1;
195		if (!usbgecko_detect()) {
196			return;
197		}
198	}
199
200	cn_tab = &usbgecko_consdev;
201	cn_init_magic(&usbgecko_cnmstate);
202	cn_set_magic("\047\001");
203
204	usbgecko_command(USBGECKO_CMD_LED_ON);
205	usbgecko_found = true;
206}
207
208static int
209usbgecko_match(device_t parent, cfdata_t cf, void *aux)
210{
211	struct exi_attach_args * const eaa = aux;
212
213	return usbgecko_found &&
214	       eaa->eaa_id == 0 &&
215	       eaa->eaa_chan == usbgecko_chan &&
216	       eaa->eaa_device == 0;
217}
218
219static void
220usbgecko_attach(device_t parent, device_t self, void *aux)
221{
222	struct usbgecko_softc *sc = device_private(self);
223	struct exi_attach_args * const eaa = aux;
224
225	aprint_naive("\n");
226	aprint_normal(": USB Gecko\n");
227
228	sc->sc_dev = self;
229	sc->sc_chan = eaa->eaa_chan;
230	sc->sc_device = eaa->eaa_device;
231
232	usbgecko_sc = sc;
233}
234