xref: /freebsd/sys/dev/uart/uart_dev_snps.c (revision b3e7694832e81d7a904a10f525f8797b753bf0d3)
1 /*-
2  * Copyright (c) 2016 Jared McNeill <jmcneill@invisible.ca>
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
18  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
19  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
20  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
21  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23  * SUCH DAMAGE.
24  */
25 
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
28 
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/bus.h>
32 #include <sys/kernel.h>
33 #include <sys/module.h>
34 #include <machine/bus.h>
35 
36 #include <dev/uart/uart.h>
37 #include <dev/uart/uart_bus.h>
38 #include <dev/uart/uart_cpu_fdt.h>
39 #include <dev/uart/uart_dev_ns8250.h>
40 
41 #include <dev/ofw/ofw_bus.h>
42 #include <dev/ofw/ofw_bus_subr.h>
43 
44 #include <dev/extres/clk/clk.h>
45 #include <dev/extres/hwreset/hwreset.h>
46 
47 #include "uart_if.h"
48 
49 struct snps_softc {
50 	struct ns8250_softc	ns8250;
51 
52 	clk_t			baudclk;
53 	clk_t			apb_pclk;
54 	hwreset_t		reset;
55 };
56 
57 /*
58  * To use early printf on 64 bits Allwinner SoC, add to kernel config
59  * options SOCDEV_PA=0x0
60  * options SOCDEV_VA=0x40000000
61  * options EARLY_PRINTF
62  *
63  * To use early printf on 32 bits Allwinner SoC, add to kernel config
64  * options SOCDEV_PA=0x01C00000
65  * options SOCDEV_VA=0x10000000
66  * options EARLY_PRINTF
67  *
68  * remove the if 0
69 */
70 #if 0
71 #ifdef EARLY_PRINTF
72 static void
73 uart_snps_early_putc(int c)
74 {
75 	volatile uint32_t *stat;
76 	volatile uint32_t *tx;
77 
78 #ifdef ALLWINNER_64
79 	stat = (uint32_t *) (SOCDEV_VA + 0x1C2807C);
80 	tx = (uint32_t *) (SOCDEV_VA + 0x1C28000);
81 #endif
82 #ifdef ALLWINNER_32
83 	stat = (uint32_t *) (SOCDEV_VA + 0x2807C);
84 	tx = (uint32_t *) (SOCDEV_VA + 0x28000);
85 #endif
86 
87 	while ((*stat & (1 << 2)) == 0)
88 		continue;
89 	*tx = c;
90 }
91 early_putc_t *early_putc = uart_snps_early_putc;
92 #endif /* EARLY_PRINTF */
93 #endif
94 
95 static kobj_method_t snps_methods[] = {
96 	KOBJMETHOD(uart_probe,		ns8250_bus_probe),
97 	KOBJMETHOD(uart_attach,		ns8250_bus_attach),
98 	KOBJMETHOD(uart_detach,		ns8250_bus_detach),
99 	KOBJMETHOD(uart_flush,		ns8250_bus_flush),
100 	KOBJMETHOD(uart_getsig,		ns8250_bus_getsig),
101 	KOBJMETHOD(uart_ioctl,		ns8250_bus_ioctl),
102 	KOBJMETHOD(uart_ipend,		ns8250_bus_ipend),
103 	KOBJMETHOD(uart_param,		ns8250_bus_param),
104 	KOBJMETHOD(uart_receive,	ns8250_bus_receive),
105 	KOBJMETHOD(uart_setsig,		ns8250_bus_setsig),
106 	KOBJMETHOD(uart_transmit,	ns8250_bus_transmit),
107 	KOBJMETHOD(uart_grab,		ns8250_bus_grab),
108 	KOBJMETHOD(uart_ungrab,		ns8250_bus_ungrab),
109 	KOBJMETHOD_END
110 };
111 
112 struct uart_class uart_snps_class = {
113 	"snps",
114 	snps_methods,
115 	sizeof(struct snps_softc),
116 	.uc_ops = &uart_ns8250_ops,
117 	.uc_range = 8,
118 	.uc_rclk = 0,
119 };
120 
121 static struct ofw_compat_data compat_data[] = {
122 	{ "snps,dw-apb-uart",		(uintptr_t)&uart_snps_class },
123 	{ "marvell,armada-38x-uart",	(uintptr_t)&uart_snps_class },
124 	{ NULL,				(uintptr_t)NULL }
125 };
126 UART_FDT_CLASS(compat_data);
127 
128 static int
129 snps_get_clocks(device_t dev, clk_t *baudclk, clk_t *apb_pclk)
130 {
131 
132 	*baudclk = NULL;
133 	*apb_pclk = NULL;
134 
135 	/* Baud clock is either named "baudclk", or there is a single
136 	 * unnamed clock.
137 	 */
138 	if (clk_get_by_ofw_name(dev, 0, "baudclk", baudclk) != 0 &&
139 	    clk_get_by_ofw_index(dev, 0, 0, baudclk) != 0)
140 		return (ENOENT);
141 
142 	/* APB peripheral clock is optional */
143 	(void)clk_get_by_ofw_name(dev, 0, "apb_pclk", apb_pclk);
144 
145 	return (0);
146 }
147 
148 static int
149 snps_probe(device_t dev)
150 {
151 	struct snps_softc *sc;
152 	struct uart_class *uart_class;
153 	phandle_t node;
154 	uint32_t shift, iowidth, clock;
155 	uint64_t freq;
156 	int error;
157 	clk_t baudclk, apb_pclk;
158 	hwreset_t reset;
159 
160 	if (!ofw_bus_status_okay(dev))
161 		return (ENXIO);
162 
163 	uart_class = (struct uart_class *)ofw_bus_search_compatible(dev,
164 	    compat_data)->ocd_data;
165 	if (uart_class == NULL)
166 		return (ENXIO);
167 
168 	freq = 0;
169 	sc = device_get_softc(dev);
170 	sc->ns8250.base.sc_class = uart_class;
171 
172 	node = ofw_bus_get_node(dev);
173 	if (OF_getencprop(node, "reg-shift", &shift, sizeof(shift)) <= 0)
174 		shift = 0;
175 	if (OF_getencprop(node, "reg-io-width", &iowidth, sizeof(iowidth)) <= 0)
176 		iowidth = 1;
177 	if (OF_getencprop(node, "clock-frequency", &clock, sizeof(clock)) <= 0)
178 		clock = 0;
179 
180 	if (hwreset_get_by_ofw_idx(dev, 0, 0, &reset) == 0) {
181 		error = hwreset_deassert(reset);
182 		if (error != 0) {
183 			device_printf(dev, "cannot de-assert reset\n");
184 			return (error);
185 		}
186 	}
187 
188 	if (snps_get_clocks(dev, &baudclk, &apb_pclk) == 0) {
189 		error = clk_enable(baudclk);
190 		if (error != 0) {
191 			device_printf(dev, "cannot enable baud clock\n");
192 			return (error);
193 		}
194 		if (apb_pclk != NULL) {
195 			error = clk_enable(apb_pclk);
196 			if (error != 0) {
197 				device_printf(dev,
198 				    "cannot enable peripheral clock\n");
199 				return (error);
200 			}
201 		}
202 
203 		if (clock == 0) {
204 			error = clk_get_freq(baudclk, &freq);
205 			if (error != 0) {
206 				device_printf(dev, "cannot get frequency\n");
207 				return (error);
208 			}
209 			clock = (uint32_t)freq;
210 		}
211 	}
212 
213 	if (bootverbose && clock == 0)
214 		device_printf(dev, "could not determine frequency\n");
215 
216 	error = uart_bus_probe(dev, (int)shift, (int)iowidth, (int)clock, 0, 0, UART_F_BUSY_DETECT);
217 	if (error > 0)
218 		return (error);
219 
220 	/* XXX uart_bus_probe has changed the softc, so refresh it */
221 	sc = device_get_softc(dev);
222 
223 	/* Store clock and reset handles for detach */
224 	sc->baudclk = baudclk;
225 	sc->apb_pclk = apb_pclk;
226 	sc->reset = reset;
227 
228 	return (BUS_PROBE_VENDOR);
229 }
230 
231 static int
232 snps_detach(device_t dev)
233 {
234 	struct snps_softc *sc;
235 	clk_t baudclk, apb_pclk;
236 	hwreset_t reset;
237 	int error;
238 
239 	sc = device_get_softc(dev);
240 	baudclk = sc->baudclk;
241 	apb_pclk = sc->apb_pclk;
242 	reset = sc->reset;
243 
244 	error = uart_bus_detach(dev);
245 	if (error != 0)
246 		return (error);
247 
248 	if (reset != NULL) {
249 		error = hwreset_assert(reset);
250 		if (error != 0) {
251 			device_printf(dev, "cannot assert reset\n");
252 			return (error);
253 		}
254 		hwreset_release(reset);
255 	}
256 	if (apb_pclk != NULL) {
257 		error = clk_release(apb_pclk);
258 		if (error != 0) {
259 			device_printf(dev, "cannot release peripheral clock\n");
260 			return (error);
261 		}
262 	}
263 	if (baudclk != NULL) {
264 		error = clk_release(baudclk);
265 		if (error != 0) {
266 			device_printf(dev, "cannot release baud clock\n");
267 			return (error);
268 		}
269 	}
270 
271 	return (0);
272 }
273 
274 static device_method_t snps_bus_methods[] = {
275 	/* Device interface */
276 	DEVMETHOD(device_probe,		snps_probe),
277 	DEVMETHOD(device_attach,	uart_bus_attach),
278 	DEVMETHOD(device_detach, 	snps_detach),
279 	DEVMETHOD_END
280 };
281 
282 static driver_t snps_uart_driver = {
283 	uart_driver_name,
284 	snps_bus_methods,
285 	sizeof(struct snps_softc)
286 };
287 
288 DRIVER_MODULE(uart_snps, simplebus, snps_uart_driver, 0, 0);
289