xref: /freebsd/sys/dev/usb/serial/umcs.c (revision 2008043f386721d58158e37e0d7e50df8095942d)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2010 Lev Serebryakov <lev@FreeBSD.org>.
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 AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 /*
30  * This driver supports several multiport USB-to-RS232 serial adapters driven
31  * by MosChip mos7820 and mos7840, bridge chips.
32  * The adapters are sold under many different brand names.
33  *
34  * Datasheets are available at MosChip www site at
35  * http://www.moschip.com.  The datasheets don't contain full
36  * programming information for the chip.
37  *
38  * It is normal to have only two enabled ports in devices, based on
39  * quad-port mos7840.
40  *
41  */
42 #include <sys/cdefs.h>
43 #include <sys/stdint.h>
44 #include <sys/stddef.h>
45 #include <sys/param.h>
46 #include <sys/queue.h>
47 #include <sys/types.h>
48 #include <sys/systm.h>
49 #include <sys/kernel.h>
50 #include <sys/bus.h>
51 #include <sys/linker_set.h>
52 #include <sys/module.h>
53 #include <sys/lock.h>
54 #include <sys/mutex.h>
55 #include <sys/condvar.h>
56 #include <sys/sysctl.h>
57 #include <sys/sx.h>
58 #include <sys/unistd.h>
59 #include <sys/callout.h>
60 #include <sys/malloc.h>
61 #include <sys/priv.h>
62 
63 #include <dev/usb/usb.h>
64 #include <dev/usb/usbdi.h>
65 #include <dev/usb/usbdi_util.h>
66 #include <dev/usb/usb_cdc.h>
67 #include "usbdevs.h"
68 
69 #define	USB_DEBUG_VAR umcs_debug
70 #include <dev/usb/usb_debug.h>
71 #include <dev/usb/usb_process.h>
72 
73 #include <dev/usb/serial/usb_serial.h>
74 
75 #include <dev/usb/serial/umcs.h>
76 
77 #define	UMCS7840_MODVER	1
78 
79 #ifdef USB_DEBUG
80 static int umcs_debug = 0;
81 
82 static SYSCTL_NODE(_hw_usb, OID_AUTO, umcs, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
83     "USB umcs quadport serial adapter");
84 SYSCTL_INT(_hw_usb_umcs, OID_AUTO, debug, CTLFLAG_RWTUN, &umcs_debug, 0, "Debug level");
85 #endif					/* USB_DEBUG */
86 
87 /*
88  * Two-port devices (both with 7820 chip and 7840 chip configured as two-port)
89  * have ports 0 and 2, with ports 1 and 3 omitted.
90  * So,PHYSICAL port numbers (indexes) on two-port device will be 0 and 2.
91  * This driver trys to use physical numbers as much as possible.
92  */
93 
94 /*
95  * Indexed by PHYSICAL port number.
96  * Pack non-regular registers to array to easier if-less access.
97  */
98 struct umcs7840_port_registers {
99 	uint8_t	reg_sp;			/* SP register. */
100 	uint8_t	reg_control;		/* CONTROL register. */
101 	uint8_t	reg_dcr;		/* DCR0 register. DCR1 & DCR2 can be
102 					 * calculated */
103 };
104 
105 static const struct umcs7840_port_registers umcs7840_port_registers[UMCS7840_MAX_PORTS] = {
106 	{.reg_sp = MCS7840_DEV_REG_SP1,.reg_control = MCS7840_DEV_REG_CONTROL1,.reg_dcr = MCS7840_DEV_REG_DCR0_1},
107 	{.reg_sp = MCS7840_DEV_REG_SP2,.reg_control = MCS7840_DEV_REG_CONTROL2,.reg_dcr = MCS7840_DEV_REG_DCR0_2},
108 	{.reg_sp = MCS7840_DEV_REG_SP3,.reg_control = MCS7840_DEV_REG_CONTROL3,.reg_dcr = MCS7840_DEV_REG_DCR0_3},
109 	{.reg_sp = MCS7840_DEV_REG_SP4,.reg_control = MCS7840_DEV_REG_CONTROL4,.reg_dcr = MCS7840_DEV_REG_DCR0_4},
110 };
111 
112 enum {
113 	UMCS7840_BULK_RD_EP,
114 	UMCS7840_BULK_WR_EP,
115 	UMCS7840_N_TRANSFERS
116 };
117 
118 struct umcs7840_softc_oneport {
119 	struct usb_xfer *sc_xfer[UMCS7840_N_TRANSFERS];	/* Control structures
120 							 * for two transfers */
121 
122 	uint8_t	sc_lcr;			/* local line control register */
123 	uint8_t	sc_mcr;			/* local modem control register */
124 };
125 
126 struct umcs7840_softc {
127 	struct ucom_super_softc sc_super_ucom;
128 	struct ucom_softc sc_ucom[UMCS7840_MAX_PORTS];	/* Need to be continuous
129 							 * array, so indexed by
130 							 * LOGICAL port
131 							 * (subunit) number */
132 
133 	struct usb_xfer *sc_intr_xfer;	/* Interrupt endpoint */
134 
135 	device_t sc_dev;		/* Device for error prints */
136 	struct usb_device *sc_udev;	/* USB Device for all operations */
137 	struct mtx sc_mtx;		/* ucom requires this */
138 
139 	uint8_t	sc_driver_done;		/* Flag when enumeration is finished */
140 
141 	uint8_t	sc_numports;		/* Number of ports (subunits) */
142 	struct umcs7840_softc_oneport sc_ports[UMCS7840_MAX_PORTS];	/* Indexed by PHYSICAL
143 									 * port number. */
144 };
145 
146 /* prototypes */
147 static usb_error_t umcs7840_get_reg_sync(struct umcs7840_softc *, uint8_t, uint8_t *);
148 static usb_error_t umcs7840_set_reg_sync(struct umcs7840_softc *, uint8_t, uint8_t);
149 static usb_error_t umcs7840_get_UART_reg_sync(struct umcs7840_softc *, uint8_t, uint8_t, uint8_t *);
150 static usb_error_t umcs7840_set_UART_reg_sync(struct umcs7840_softc *, uint8_t, uint8_t, uint8_t);
151 
152 static usb_error_t umcs7840_set_baudrate(struct umcs7840_softc *, uint8_t, uint32_t);
153 static usb_error_t umcs7840_calc_baudrate(uint32_t rate, uint16_t *, uint8_t *);
154 
155 static void	umcs7840_free(struct ucom_softc *);
156 static void umcs7840_cfg_get_status(struct ucom_softc *, uint8_t *, uint8_t *);
157 static void umcs7840_cfg_set_dtr(struct ucom_softc *, uint8_t);
158 static void umcs7840_cfg_set_rts(struct ucom_softc *, uint8_t);
159 static void umcs7840_cfg_set_break(struct ucom_softc *, uint8_t);
160 static void umcs7840_cfg_param(struct ucom_softc *, struct termios *);
161 static void umcs7840_cfg_open(struct ucom_softc *);
162 static void umcs7840_cfg_close(struct ucom_softc *);
163 
164 static int umcs7840_pre_param(struct ucom_softc *, struct termios *);
165 
166 static void umcs7840_start_read(struct ucom_softc *);
167 static void umcs7840_stop_read(struct ucom_softc *);
168 
169 static void umcs7840_start_write(struct ucom_softc *);
170 static void umcs7840_stop_write(struct ucom_softc *);
171 
172 static void umcs7840_poll(struct ucom_softc *ucom);
173 
174 static device_probe_t umcs7840_probe;
175 static device_attach_t umcs7840_attach;
176 static device_detach_t umcs7840_detach;
177 static void umcs7840_free_softc(struct umcs7840_softc *);
178 
179 static usb_callback_t umcs7840_intr_callback;
180 static usb_callback_t umcs7840_read_callback1;
181 static usb_callback_t umcs7840_read_callback2;
182 static usb_callback_t umcs7840_read_callback3;
183 static usb_callback_t umcs7840_read_callback4;
184 static usb_callback_t umcs7840_write_callback1;
185 static usb_callback_t umcs7840_write_callback2;
186 static usb_callback_t umcs7840_write_callback3;
187 static usb_callback_t umcs7840_write_callback4;
188 
189 static void umcs7840_read_callbackN(struct usb_xfer *, usb_error_t, uint8_t);
190 static void umcs7840_write_callbackN(struct usb_xfer *, usb_error_t, uint8_t);
191 
192 /* Indexed by LOGICAL port number (subunit), so two-port device uses 0 & 1 */
193 static usb_callback_t *umcs7840_rw_callbacks[UMCS7840_MAX_PORTS][UMCS7840_N_TRANSFERS] = {
194 	{&umcs7840_read_callback1, &umcs7840_write_callback1},
195 	{&umcs7840_read_callback2, &umcs7840_write_callback2},
196 	{&umcs7840_read_callback3, &umcs7840_write_callback3},
197 	{&umcs7840_read_callback4, &umcs7840_write_callback4},
198 };
199 
200 static const struct usb_config umcs7840_bulk_config_data[UMCS7840_N_TRANSFERS] = {
201 	[UMCS7840_BULK_RD_EP] = {
202 		.type = UE_BULK,
203 		.endpoint = 0x01,
204 		.direction = UE_DIR_IN,
205 		.flags = {.pipe_bof = 1,.short_xfer_ok = 1,},
206 		.bufsize = 0,		/* use wMaxPacketSize */
207 		.callback = &umcs7840_read_callback1,
208 		.if_index = 0,
209 	},
210 
211 	[UMCS7840_BULK_WR_EP] = {
212 		.type = UE_BULK,
213 		.endpoint = 0x02,
214 		.direction = UE_DIR_OUT,
215 		.flags = {.pipe_bof = 1,.short_xfer_ok = 1,},
216 		.bufsize = 0,		/* use wMaxPacketSize */
217 		.callback = &umcs7840_write_callback1,
218 		.if_index = 0,
219 	},
220 };
221 
222 static const struct usb_config umcs7840_intr_config_data[1] = {
223 	[0] = {
224 		.type = UE_INTERRUPT,
225 		.endpoint = 0x09,
226 		.direction = UE_DIR_IN,
227 		.flags = {.pipe_bof = 1,.short_xfer_ok = 1,},
228 		.bufsize = 0,		/* use wMaxPacketSize */
229 		.callback = &umcs7840_intr_callback,
230 		.if_index = 0,
231 	},
232 };
233 
234 static struct ucom_callback umcs7840_callback = {
235 	.ucom_cfg_get_status = &umcs7840_cfg_get_status,
236 
237 	.ucom_cfg_set_dtr = &umcs7840_cfg_set_dtr,
238 	.ucom_cfg_set_rts = &umcs7840_cfg_set_rts,
239 	.ucom_cfg_set_break = &umcs7840_cfg_set_break,
240 
241 	.ucom_cfg_param = &umcs7840_cfg_param,
242 	.ucom_cfg_open = &umcs7840_cfg_open,
243 	.ucom_cfg_close = &umcs7840_cfg_close,
244 
245 	.ucom_pre_param = &umcs7840_pre_param,
246 
247 	.ucom_start_read = &umcs7840_start_read,
248 	.ucom_stop_read = &umcs7840_stop_read,
249 
250 	.ucom_start_write = &umcs7840_start_write,
251 	.ucom_stop_write = &umcs7840_stop_write,
252 
253 	.ucom_poll = &umcs7840_poll,
254 	.ucom_free = &umcs7840_free,
255 };
256 
257 static const STRUCT_USB_HOST_ID umcs7840_devs[] = {
258 	{USB_VPI(USB_VENDOR_MOSCHIP, USB_PRODUCT_MOSCHIP_MCS7820, 0)},
259 	{USB_VPI(USB_VENDOR_MOSCHIP, USB_PRODUCT_MOSCHIP_MCS7840, 0)},
260 };
261 
262 static device_method_t umcs7840_methods[] = {
263 	DEVMETHOD(device_probe, umcs7840_probe),
264 	DEVMETHOD(device_attach, umcs7840_attach),
265 	DEVMETHOD(device_detach, umcs7840_detach),
266 	DEVMETHOD_END
267 };
268 
269 static driver_t umcs7840_driver = {
270 	.name = "umcs7840",
271 	.methods = umcs7840_methods,
272 	.size = sizeof(struct umcs7840_softc),
273 };
274 
275 DRIVER_MODULE(umcs7840, uhub, umcs7840_driver, 0, 0);
276 MODULE_DEPEND(umcs7840, ucom, 1, 1, 1);
277 MODULE_DEPEND(umcs7840, usb, 1, 1, 1);
278 MODULE_VERSION(umcs7840, UMCS7840_MODVER);
279 USB_PNP_HOST_INFO(umcs7840_devs);
280 
281 static int
282 umcs7840_probe(device_t dev)
283 {
284 	struct usb_attach_arg *uaa = device_get_ivars(dev);
285 
286 	if (uaa->usb_mode != USB_MODE_HOST)
287 		return (ENXIO);
288 	if (uaa->info.bConfigIndex != MCS7840_CONFIG_INDEX)
289 		return (ENXIO);
290 	if (uaa->info.bIfaceIndex != MCS7840_IFACE_INDEX)
291 		return (ENXIO);
292 	return (usbd_lookup_id_by_uaa(umcs7840_devs, sizeof(umcs7840_devs), uaa));
293 }
294 
295 static int
296 umcs7840_attach(device_t dev)
297 {
298 	struct usb_config umcs7840_config_tmp[UMCS7840_N_TRANSFERS];
299 	struct usb_attach_arg *uaa = device_get_ivars(dev);
300 	struct umcs7840_softc *sc = device_get_softc(dev);
301 
302 	uint8_t iface_index = MCS7840_IFACE_INDEX;
303 	int error;
304 	int subunit;
305 	int n;
306 	uint8_t data;
307 
308 	for (n = 0; n < UMCS7840_N_TRANSFERS; ++n)
309 		umcs7840_config_tmp[n] = umcs7840_bulk_config_data[n];
310 
311 	device_set_usb_desc(dev);
312 	mtx_init(&sc->sc_mtx, "umcs7840", NULL, MTX_DEF);
313 	ucom_ref(&sc->sc_super_ucom);
314 
315 	sc->sc_dev = dev;
316 	sc->sc_udev = uaa->device;
317 
318 	/*
319 	 * Get number of ports
320 	 * Documentation (full datasheet) says, that number of ports is
321 	 * set as MCS7840_DEV_MODE_SELECT24S bit in MODE R/Only
322 	 * register. But vendor driver uses these undocumented
323 	 * register & bit.
324 	 *
325 	 * Experiments show, that MODE register can have `0'
326 	 * (4 ports) bit on 2-port device, so use vendor driver's way.
327 	 *
328 	 * Also, see notes in header file for these constants.
329 	 */
330 	umcs7840_get_reg_sync(sc, MCS7840_DEV_REG_GPIO, &data);
331 	if (data & MCS7840_DEV_GPIO_4PORTS) {
332 		sc->sc_numports = 4;
333 		/* Store physical port numbers in sc_portno */
334 		sc->sc_ucom[0].sc_portno = 0;
335 		sc->sc_ucom[1].sc_portno = 1;
336 		sc->sc_ucom[2].sc_portno = 2;
337 		sc->sc_ucom[3].sc_portno = 3;
338 	} else {
339 		sc->sc_numports = 2;
340 		/* Store physical port numbers in sc_portno */
341 		sc->sc_ucom[0].sc_portno = 0;
342 		sc->sc_ucom[1].sc_portno = 2;	/* '1' is skipped */
343 	}
344 	device_printf(dev, "Chip mcs%04x, found %d active ports\n", uaa->info.idProduct, sc->sc_numports);
345 	if (!umcs7840_get_reg_sync(sc, MCS7840_DEV_REG_MODE, &data)) {
346 		device_printf(dev, "On-die configuration: RST: active %s, HRD: %s, PLL: %s, POR: %s, Ports: %s, EEPROM write %s, IrDA is %savailable\n",
347 		    (data & MCS7840_DEV_MODE_RESET) ? "low" : "high",
348 		    (data & MCS7840_DEV_MODE_SER_PRSNT) ? "yes" : "no",
349 		    (data & MCS7840_DEV_MODE_PLLBYPASS) ? "bypassed" : "avail",
350 		    (data & MCS7840_DEV_MODE_PORBYPASS) ? "bypassed" : "avail",
351 		    (data & MCS7840_DEV_MODE_SELECT24S) ? "2" : "4",
352 		    (data & MCS7840_DEV_MODE_EEPROMWR) ? "enabled" : "disabled",
353 		    (data & MCS7840_DEV_MODE_IRDA) ? "" : "not ");
354 	}
355 	/* Setup all transfers */
356 	for (subunit = 0; subunit < sc->sc_numports; ++subunit) {
357 		for (n = 0; n < UMCS7840_N_TRANSFERS; ++n) {
358 			/* Set endpoint address */
359 			umcs7840_config_tmp[n].endpoint = umcs7840_bulk_config_data[n].endpoint + 2 * sc->sc_ucom[subunit].sc_portno;
360 			umcs7840_config_tmp[n].callback = umcs7840_rw_callbacks[subunit][n];
361 		}
362 		error = usbd_transfer_setup(uaa->device,
363 		    &iface_index, sc->sc_ports[sc->sc_ucom[subunit].sc_portno].sc_xfer, umcs7840_config_tmp,
364 		    UMCS7840_N_TRANSFERS, sc, &sc->sc_mtx);
365 		if (error) {
366 			device_printf(dev, "allocating USB transfers failed for subunit %d of %d\n",
367 			    subunit + 1, sc->sc_numports);
368 			goto detach;
369 		}
370 	}
371 	error = usbd_transfer_setup(uaa->device,
372 	    &iface_index, &sc->sc_intr_xfer, umcs7840_intr_config_data,
373 	    1, sc, &sc->sc_mtx);
374 	if (error) {
375 		device_printf(dev, "allocating USB transfers failed for interrupt\n");
376 		goto detach;
377 	}
378 	/* clear stall at first run */
379 	mtx_lock(&sc->sc_mtx);
380 	for (subunit = 0; subunit < sc->sc_numports; ++subunit) {
381 		usbd_xfer_set_stall(sc->sc_ports[sc->sc_ucom[subunit].sc_portno].sc_xfer[UMCS7840_BULK_RD_EP]);
382 		usbd_xfer_set_stall(sc->sc_ports[sc->sc_ucom[subunit].sc_portno].sc_xfer[UMCS7840_BULK_WR_EP]);
383 	}
384 	mtx_unlock(&sc->sc_mtx);
385 
386 	error = ucom_attach(&sc->sc_super_ucom, sc->sc_ucom, sc->sc_numports, sc,
387 	    &umcs7840_callback, &sc->sc_mtx);
388 	if (error)
389 		goto detach;
390 
391 	ucom_set_pnpinfo_usb(&sc->sc_super_ucom, dev);
392 
393 	return (0);
394 
395 detach:
396 	umcs7840_detach(dev);
397 	return (ENXIO);
398 }
399 
400 static int
401 umcs7840_detach(device_t dev)
402 {
403 	struct umcs7840_softc *sc = device_get_softc(dev);
404 	int subunit;
405 
406 	ucom_detach(&sc->sc_super_ucom, sc->sc_ucom);
407 
408 	for (subunit = 0; subunit < sc->sc_numports; ++subunit)
409 		usbd_transfer_unsetup(sc->sc_ports[sc->sc_ucom[subunit].sc_portno].sc_xfer, UMCS7840_N_TRANSFERS);
410 	usbd_transfer_unsetup(&sc->sc_intr_xfer, 1);
411 
412 	device_claim_softc(dev);
413 
414 	umcs7840_free_softc(sc);
415 
416 	return (0);
417 }
418 
419 UCOM_UNLOAD_DRAIN(umcs7840);
420 
421 static void
422 umcs7840_free_softc(struct umcs7840_softc *sc)
423 {
424 	if (ucom_unref(&sc->sc_super_ucom)) {
425 		mtx_destroy(&sc->sc_mtx);
426 		device_free_softc(sc);
427 	}
428 }
429 
430 static void
431 umcs7840_free(struct ucom_softc *ucom)
432 {
433 	umcs7840_free_softc(ucom->sc_parent);
434 }
435 
436 static void
437 umcs7840_cfg_open(struct ucom_softc *ucom)
438 {
439 	struct umcs7840_softc *sc = ucom->sc_parent;
440 	uint16_t pn = ucom->sc_portno;
441 	uint8_t data;
442 
443 	/* If it very first open, finish global configuration */
444 	if (!sc->sc_driver_done) {
445 		/*
446 		 * USB enumeration is finished, pass internal memory to FIFOs
447 		 * If it is done in the end of "attach", kernel panics.
448 		 */
449 		if (umcs7840_get_reg_sync(sc, MCS7840_DEV_REG_CONTROL1, &data))
450 			return;
451 		data |= MCS7840_DEV_CONTROL1_DRIVER_DONE;
452 		if (umcs7840_set_reg_sync(sc, MCS7840_DEV_REG_CONTROL1, data))
453 			return;
454 		sc->sc_driver_done = 1;
455 	}
456 	/* Toggle reset bit on-off */
457 	if (umcs7840_get_reg_sync(sc, umcs7840_port_registers[pn].reg_sp, &data))
458 		return;
459 	data |= MCS7840_DEV_SPx_UART_RESET;
460 	if (umcs7840_set_reg_sync(sc, umcs7840_port_registers[pn].reg_sp, data))
461 		return;
462 	data &= ~MCS7840_DEV_SPx_UART_RESET;
463 	if (umcs7840_set_reg_sync(sc, umcs7840_port_registers[pn].reg_sp, data))
464 		return;
465 
466 	/* Set RS-232 mode */
467 	if (umcs7840_set_UART_reg_sync(sc, pn, MCS7840_UART_REG_SCRATCHPAD, MCS7840_UART_SCRATCHPAD_RS232))
468 		return;
469 
470 	/* Disable RX on time of initialization */
471 	if (umcs7840_get_reg_sync(sc, umcs7840_port_registers[pn].reg_control, &data))
472 		return;
473 	data |= MCS7840_DEV_CONTROLx_RX_DISABLE;
474 	if (umcs7840_set_reg_sync(sc, umcs7840_port_registers[pn].reg_control, data))
475 		return;
476 
477 	/* Disable all interrupts */
478 	if (umcs7840_set_UART_reg_sync(sc, pn, MCS7840_UART_REG_IER, 0))
479 		return;
480 
481 	/* Reset FIFO -- documented */
482 	if (umcs7840_set_UART_reg_sync(sc, pn, MCS7840_UART_REG_FCR, 0))
483 		return;
484 	if (umcs7840_set_UART_reg_sync(sc, pn, MCS7840_UART_REG_FCR,
485 	    MCS7840_UART_FCR_ENABLE | MCS7840_UART_FCR_FLUSHRHR |
486 	    MCS7840_UART_FCR_FLUSHTHR | MCS7840_UART_FCR_RTL_1_14))
487 		return;
488 
489 	/* Set 8 bit, no parity, 1 stop bit -- documented */
490 	sc->sc_ports[pn].sc_lcr = MCS7840_UART_LCR_DATALEN8 | MCS7840_UART_LCR_STOPB1;
491 	if (umcs7840_set_UART_reg_sync(sc, pn, MCS7840_UART_REG_LCR, sc->sc_ports[pn].sc_lcr))
492 		return;
493 
494 	/*
495 	 * Enable DTR/RTS on modem control, enable modem interrupts --
496 	 * documented
497 	 */
498 	sc->sc_ports[pn].sc_mcr = MCS7840_UART_MCR_IE;
499 	if (ucom->sc_tty == NULL || (ucom->sc_tty->t_termios.c_cflag & CNO_RTSDTR) == 0)
500 		sc->sc_ports[pn].sc_mcr |= MCS7840_UART_MCR_DTR | MCS7840_UART_MCR_RTS;
501 	if (umcs7840_set_UART_reg_sync(sc, pn, MCS7840_UART_REG_MCR, sc->sc_ports[pn].sc_mcr))
502 		return;
503 
504 	/* Clearing Bulkin and Bulkout FIFO */
505 	if (umcs7840_get_reg_sync(sc, umcs7840_port_registers[pn].reg_sp, &data))
506 		return;
507 	data |= MCS7840_DEV_SPx_RESET_OUT_FIFO | MCS7840_DEV_SPx_RESET_IN_FIFO;
508 	if (umcs7840_set_reg_sync(sc, umcs7840_port_registers[pn].reg_sp, data))
509 		return;
510 	data &= ~(MCS7840_DEV_SPx_RESET_OUT_FIFO | MCS7840_DEV_SPx_RESET_IN_FIFO);
511 	if (umcs7840_set_reg_sync(sc, umcs7840_port_registers[pn].reg_sp, data))
512 		return;
513 
514 	/* Set speed 9600 */
515 	if (umcs7840_set_baudrate(sc, pn, 9600))
516 		return;
517 
518 	/* Finally enable all interrupts -- documented */
519 	/*
520 	 * Copied from vendor driver, I don't know why we should read LCR
521 	 * here
522 	 */
523 	if (umcs7840_get_UART_reg_sync(sc, pn, MCS7840_UART_REG_LCR, &sc->sc_ports[pn].sc_lcr))
524 		return;
525 	if (umcs7840_set_UART_reg_sync(sc, pn, MCS7840_UART_REG_IER,
526 	    MCS7840_UART_IER_RXSTAT | MCS7840_UART_IER_MODEM))
527 		return;
528 
529 	/* Enable RX */
530 	if (umcs7840_get_reg_sync(sc, umcs7840_port_registers[pn].reg_control, &data))
531 		return;
532 	data &= ~MCS7840_DEV_CONTROLx_RX_DISABLE;
533 	if (umcs7840_set_reg_sync(sc, umcs7840_port_registers[pn].reg_control, data))
534 		return;
535 
536 	DPRINTF("Port %d has been opened\n", pn);
537 }
538 
539 static void
540 umcs7840_cfg_close(struct ucom_softc *ucom)
541 {
542 	struct umcs7840_softc *sc = ucom->sc_parent;
543 	uint16_t pn = ucom->sc_portno;
544 	uint8_t data;
545 
546 	umcs7840_stop_read(ucom);
547 	umcs7840_stop_write(ucom);
548 
549 	umcs7840_set_UART_reg_sync(sc, pn, MCS7840_UART_REG_MCR, 0);
550 	umcs7840_set_UART_reg_sync(sc, pn, MCS7840_UART_REG_IER, 0);
551 
552 	/* Disable RX */
553 	if (umcs7840_get_reg_sync(sc, umcs7840_port_registers[pn].reg_control, &data))
554 		return;
555 	data |= MCS7840_DEV_CONTROLx_RX_DISABLE;
556 	if (umcs7840_set_reg_sync(sc, umcs7840_port_registers[pn].reg_control, data))
557 		return;
558 	DPRINTF("Port %d has been closed\n", pn);
559 }
560 
561 static void
562 umcs7840_cfg_set_dtr(struct ucom_softc *ucom, uint8_t onoff)
563 {
564 	struct umcs7840_softc *sc = ucom->sc_parent;
565 	uint8_t pn = ucom->sc_portno;
566 
567 	if (onoff)
568 		sc->sc_ports[pn].sc_mcr |= MCS7840_UART_MCR_DTR;
569 	else
570 		sc->sc_ports[pn].sc_mcr &= ~MCS7840_UART_MCR_DTR;
571 
572 	umcs7840_set_UART_reg_sync(sc, pn, MCS7840_UART_REG_MCR, sc->sc_ports[pn].sc_mcr);
573 	DPRINTF("Port %d DTR set to: %s\n", pn, onoff ? "on" : "off");
574 }
575 
576 static void
577 umcs7840_cfg_set_rts(struct ucom_softc *ucom, uint8_t onoff)
578 {
579 	struct umcs7840_softc *sc = ucom->sc_parent;
580 	uint8_t pn = ucom->sc_portno;
581 
582 	if (onoff)
583 		sc->sc_ports[pn].sc_mcr |= MCS7840_UART_MCR_RTS;
584 	else
585 		sc->sc_ports[pn].sc_mcr &= ~MCS7840_UART_MCR_RTS;
586 
587 	umcs7840_set_UART_reg_sync(sc, pn, MCS7840_UART_REG_MCR, sc->sc_ports[pn].sc_mcr);
588 	DPRINTF("Port %d RTS set to: %s\n", pn, onoff ? "on" : "off");
589 }
590 
591 static void
592 umcs7840_cfg_set_break(struct ucom_softc *ucom, uint8_t onoff)
593 {
594 	struct umcs7840_softc *sc = ucom->sc_parent;
595 	uint8_t pn = ucom->sc_portno;
596 
597 	if (onoff)
598 		sc->sc_ports[pn].sc_lcr |= MCS7840_UART_LCR_BREAK;
599 	else
600 		sc->sc_ports[pn].sc_lcr &= ~MCS7840_UART_LCR_BREAK;
601 
602 	umcs7840_set_UART_reg_sync(sc, pn, MCS7840_UART_REG_LCR, sc->sc_ports[pn].sc_lcr);
603 	DPRINTF("Port %d BREAK set to: %s\n", pn, onoff ? "on" : "off");
604 }
605 
606 static void
607 umcs7840_cfg_param(struct ucom_softc *ucom, struct termios *t)
608 {
609 	struct umcs7840_softc *sc = ucom->sc_parent;
610 	uint8_t pn = ucom->sc_portno;
611 	uint8_t lcr = sc->sc_ports[pn].sc_lcr;
612 	uint8_t mcr = sc->sc_ports[pn].sc_mcr;
613 
614 	DPRINTF("Port %d config:\n", pn);
615 	if (t->c_cflag & CSTOPB) {
616 		DPRINTF("  2 stop bits\n");
617 		lcr |= MCS7840_UART_LCR_STOPB2;
618 	} else {
619 		lcr |= MCS7840_UART_LCR_STOPB1;
620 		DPRINTF("  1 stop bit\n");
621 	}
622 
623 	lcr &= ~MCS7840_UART_LCR_PARITYMASK;
624 	if (t->c_cflag & PARENB) {
625 		lcr |= MCS7840_UART_LCR_PARITYON;
626 		if (t->c_cflag & PARODD) {
627 			lcr = MCS7840_UART_LCR_PARITYODD;
628 			DPRINTF("  parity on - odd\n");
629 		} else {
630 			lcr = MCS7840_UART_LCR_PARITYEVEN;
631 			DPRINTF("  parity on - even\n");
632 		}
633 	} else {
634 		lcr &= ~MCS7840_UART_LCR_PARITYON;
635 		DPRINTF("  parity off\n");
636 	}
637 
638 	lcr &= ~MCS7840_UART_LCR_DATALENMASK;
639 	switch (t->c_cflag & CSIZE) {
640 	case CS5:
641 		lcr |= MCS7840_UART_LCR_DATALEN5;
642 		DPRINTF("  5 bit\n");
643 		break;
644 	case CS6:
645 		lcr |= MCS7840_UART_LCR_DATALEN6;
646 		DPRINTF("  6 bit\n");
647 		break;
648 	case CS7:
649 		lcr |= MCS7840_UART_LCR_DATALEN7;
650 		DPRINTF("  7 bit\n");
651 		break;
652 	case CS8:
653 		lcr |= MCS7840_UART_LCR_DATALEN8;
654 		DPRINTF("  8 bit\n");
655 		break;
656 	}
657 
658 	if (t->c_cflag & CRTSCTS) {
659 		mcr |= MCS7840_UART_MCR_CTSRTS;
660 		DPRINTF("  CTS/RTS\n");
661 	} else
662 		mcr &= ~MCS7840_UART_MCR_CTSRTS;
663 
664 	if (t->c_cflag & (CDTR_IFLOW | CDSR_OFLOW)) {
665 		mcr |= MCS7840_UART_MCR_DTRDSR;
666 		DPRINTF("  DTR/DSR\n");
667 	} else
668 		mcr &= ~MCS7840_UART_MCR_DTRDSR;
669 
670 	sc->sc_ports[pn].sc_lcr = lcr;
671 	umcs7840_set_UART_reg_sync(sc, pn, MCS7840_UART_REG_LCR, sc->sc_ports[pn].sc_lcr);
672 	DPRINTF("Port %d LCR=%02x\n", pn, sc->sc_ports[pn].sc_lcr);
673 
674 	sc->sc_ports[pn].sc_mcr = mcr;
675 	umcs7840_set_UART_reg_sync(sc, pn, MCS7840_UART_REG_MCR, sc->sc_ports[pn].sc_mcr);
676 	DPRINTF("Port %d MCR=%02x\n", pn, sc->sc_ports[pn].sc_mcr);
677 
678 	umcs7840_set_baudrate(sc, pn, t->c_ospeed);
679 }
680 
681 static int
682 umcs7840_pre_param(struct ucom_softc *ucom, struct termios *t)
683 {
684 	uint8_t clk;
685 	uint16_t divisor;
686 
687 	if (umcs7840_calc_baudrate(t->c_ospeed, &divisor, &clk) || !divisor)
688 		return (EINVAL);
689 	return (0);
690 }
691 
692 static void
693 umcs7840_start_read(struct ucom_softc *ucom)
694 {
695 	struct umcs7840_softc *sc = ucom->sc_parent;
696 	uint8_t pn = ucom->sc_portno;
697 
698 	/* Start interrupt transfer */
699 	usbd_transfer_start(sc->sc_intr_xfer);
700 
701 	/* Start read transfer */
702 	usbd_transfer_start(sc->sc_ports[pn].sc_xfer[UMCS7840_BULK_RD_EP]);
703 }
704 
705 static void
706 umcs7840_stop_read(struct ucom_softc *ucom)
707 {
708 	struct umcs7840_softc *sc = ucom->sc_parent;
709 	uint8_t pn = ucom->sc_portno;
710 
711 	/* Stop read transfer */
712 	usbd_transfer_stop(sc->sc_ports[pn].sc_xfer[UMCS7840_BULK_RD_EP]);
713 }
714 
715 static void
716 umcs7840_start_write(struct ucom_softc *ucom)
717 {
718 	struct umcs7840_softc *sc = ucom->sc_parent;
719 	uint8_t pn = ucom->sc_portno;
720 
721 	/* Start interrupt transfer */
722 	usbd_transfer_start(sc->sc_intr_xfer);
723 
724 	/* Start write transfer */
725 	usbd_transfer_start(sc->sc_ports[pn].sc_xfer[UMCS7840_BULK_WR_EP]);
726 }
727 
728 static void
729 umcs7840_stop_write(struct ucom_softc *ucom)
730 {
731 	struct umcs7840_softc *sc = ucom->sc_parent;
732 	uint8_t pn = ucom->sc_portno;
733 
734 	/* Stop write transfer */
735 	usbd_transfer_stop(sc->sc_ports[pn].sc_xfer[UMCS7840_BULK_WR_EP]);
736 }
737 
738 static void
739 umcs7840_cfg_get_status(struct ucom_softc *ucom, uint8_t *lsr, uint8_t *msr)
740 {
741 	struct umcs7840_softc *sc = ucom->sc_parent;
742 	uint8_t pn = ucom->sc_portno;
743 	uint8_t	hw_msr = 0;	/* local modem status register */
744 
745 	/*
746 	 * Read status registers.  MSR bits need translation from ns16550 to
747 	 * SER_* values.  LSR bits are ns16550 in hardware and ucom.
748 	 */
749 	umcs7840_get_UART_reg_sync(sc, pn, MCS7840_UART_REG_LSR, lsr);
750 	umcs7840_get_UART_reg_sync(sc, pn, MCS7840_UART_REG_MSR, &hw_msr);
751 
752 	if (hw_msr & MCS7840_UART_MSR_NEGCTS)
753 		*msr |= SER_CTS;
754 
755 	if (hw_msr & MCS7840_UART_MSR_NEGDCD)
756 		*msr |= SER_DCD;
757 
758 	if (hw_msr & MCS7840_UART_MSR_NEGRI)
759 		*msr |= SER_RI;
760 
761 	if (hw_msr & MCS7840_UART_MSR_NEGDSR)
762 		*msr |= SER_DSR;
763 
764 	DPRINTF("Port %d status: LSR=%02x MSR=%02x\n", ucom->sc_portno, *lsr, *msr);
765 }
766 
767 static void
768 umcs7840_intr_callback(struct usb_xfer *xfer, usb_error_t error)
769 {
770 	struct umcs7840_softc *sc = usbd_xfer_softc(xfer);
771 	struct usb_page_cache *pc;
772 	uint8_t buf[13];
773 	int actlen;
774 	int subunit;
775 
776 	usbd_xfer_status(xfer, &actlen, NULL, NULL, NULL);
777 
778 	switch (USB_GET_STATE(xfer)) {
779 	case USB_ST_TRANSFERRED:
780 		if (actlen == 5 || actlen == 13) {
781 			pc = usbd_xfer_get_frame(xfer, 0);
782 			usbd_copy_out(pc, 0, buf, actlen);
783 			/* Check status of all ports */
784 			for (subunit = 0; subunit < sc->sc_numports; ++subunit) {
785 				uint8_t pn = sc->sc_ucom[subunit].sc_portno;
786 
787 				if (buf[pn] & MCS7840_UART_ISR_NOPENDING)
788 					continue;
789 				DPRINTF("Port %d has pending interrupt: %02x (FIFO: %02x)\n", pn, buf[pn] & MCS7840_UART_ISR_INTMASK, buf[pn] & (~MCS7840_UART_ISR_INTMASK));
790 				switch (buf[pn] & MCS7840_UART_ISR_INTMASK) {
791 				case MCS7840_UART_ISR_RXERR:
792 				case MCS7840_UART_ISR_RXHASDATA:
793 				case MCS7840_UART_ISR_RXTIMEOUT:
794 				case MCS7840_UART_ISR_MSCHANGE:
795 					ucom_status_change(&sc->sc_ucom[subunit]);
796 					break;
797 				default:
798 					/* Do nothing */
799 					break;
800 				}
801 			}
802 		} else
803 			device_printf(sc->sc_dev, "Invalid interrupt data length %d", actlen);
804 		/* FALLTHROUGH */
805 	case USB_ST_SETUP:
806 tr_setup:
807 		usbd_xfer_set_frame_len(xfer, 0, usbd_xfer_max_len(xfer));
808 		usbd_transfer_submit(xfer);
809 		return;
810 
811 	default:			/* Error */
812 		if (error != USB_ERR_CANCELLED) {
813 			/* try to clear stall first */
814 			usbd_xfer_set_stall(xfer);
815 			goto tr_setup;
816 		}
817 		return;
818 	}
819 }
820 
821 static void
822 umcs7840_read_callback1(struct usb_xfer *xfer, usb_error_t error)
823 {
824 	umcs7840_read_callbackN(xfer, error, 0);
825 }
826 
827 static void
828 umcs7840_read_callback2(struct usb_xfer *xfer, usb_error_t error)
829 {
830 	umcs7840_read_callbackN(xfer, error, 1);
831 }
832 static void
833 umcs7840_read_callback3(struct usb_xfer *xfer, usb_error_t error)
834 {
835 	umcs7840_read_callbackN(xfer, error, 2);
836 }
837 
838 static void
839 umcs7840_read_callback4(struct usb_xfer *xfer, usb_error_t error)
840 {
841 	umcs7840_read_callbackN(xfer, error, 3);
842 }
843 
844 static void
845 umcs7840_read_callbackN(struct usb_xfer *xfer, usb_error_t error, uint8_t subunit)
846 {
847 	struct umcs7840_softc *sc = usbd_xfer_softc(xfer);
848 	struct ucom_softc *ucom = &sc->sc_ucom[subunit];
849 	struct usb_page_cache *pc;
850 	int actlen;
851 
852 	usbd_xfer_status(xfer, &actlen, NULL, NULL, NULL);
853 
854 	DPRINTF("Port %d read, state = %d, data length = %d\n", ucom->sc_portno, USB_GET_STATE(xfer), actlen);
855 
856 	switch (USB_GET_STATE(xfer)) {
857 	case USB_ST_TRANSFERRED:
858 		pc = usbd_xfer_get_frame(xfer, 0);
859 		ucom_put_data(ucom, pc, 0, actlen);
860 		/* FALLTHROUGH */
861 	case USB_ST_SETUP:
862 tr_setup:
863 		usbd_xfer_set_frame_len(xfer, 0, usbd_xfer_max_len(xfer));
864 		usbd_transfer_submit(xfer);
865 		return;
866 
867 	default:			/* Error */
868 		if (error != USB_ERR_CANCELLED) {
869 			/* try to clear stall first */
870 			usbd_xfer_set_stall(xfer);
871 			goto tr_setup;
872 		}
873 		return;
874 	}
875 }
876 
877 static void
878 umcs7840_write_callback1(struct usb_xfer *xfer, usb_error_t error)
879 {
880 	umcs7840_write_callbackN(xfer, error, 0);
881 }
882 
883 static void
884 umcs7840_write_callback2(struct usb_xfer *xfer, usb_error_t error)
885 {
886 	umcs7840_write_callbackN(xfer, error, 1);
887 }
888 
889 static void
890 umcs7840_write_callback3(struct usb_xfer *xfer, usb_error_t error)
891 {
892 	umcs7840_write_callbackN(xfer, error, 2);
893 }
894 
895 static void
896 umcs7840_write_callback4(struct usb_xfer *xfer, usb_error_t error)
897 {
898 	umcs7840_write_callbackN(xfer, error, 3);
899 }
900 
901 static void
902 umcs7840_write_callbackN(struct usb_xfer *xfer, usb_error_t error, uint8_t subunit)
903 {
904 	struct umcs7840_softc *sc = usbd_xfer_softc(xfer);
905 	struct ucom_softc *ucom = &sc->sc_ucom[subunit];
906 	struct usb_page_cache *pc;
907 	uint32_t actlen;
908 
909 	DPRINTF("Port %d write, state = %d\n", ucom->sc_portno, USB_GET_STATE(xfer));
910 
911 	switch (USB_GET_STATE(xfer)) {
912 	case USB_ST_SETUP:
913 	case USB_ST_TRANSFERRED:
914 tr_setup:
915 		pc = usbd_xfer_get_frame(xfer, 0);
916 		if (ucom_get_data(ucom, pc, 0, usbd_xfer_max_len(xfer), &actlen)) {
917 			DPRINTF("Port %d write, has %d bytes\n", ucom->sc_portno, actlen);
918 			usbd_xfer_set_frame_len(xfer, 0, actlen);
919 			usbd_transfer_submit(xfer);
920 		}
921 		return;
922 
923 	default:			/* Error */
924 		if (error != USB_ERR_CANCELLED) {
925 			/* try to clear stall first */
926 			usbd_xfer_set_stall(xfer);
927 			goto tr_setup;
928 		}
929 		return;
930 	}
931 }
932 
933 static void
934 umcs7840_poll(struct ucom_softc *ucom)
935 {
936 	struct umcs7840_softc *sc = ucom->sc_parent;
937 
938 	DPRINTF("Port %d poll\n", ucom->sc_portno);
939 	usbd_transfer_poll(sc->sc_ports[ucom->sc_portno].sc_xfer, UMCS7840_N_TRANSFERS);
940 	usbd_transfer_poll(&sc->sc_intr_xfer, 1);
941 }
942 
943 static usb_error_t
944 umcs7840_get_reg_sync(struct umcs7840_softc *sc, uint8_t reg, uint8_t *data)
945 {
946 	struct usb_device_request req;
947 	usb_error_t err;
948 	uint16_t len;
949 
950 	req.bmRequestType = UT_READ_VENDOR_DEVICE;
951 	req.bRequest = MCS7840_RDREQ;
952 	USETW(req.wValue, 0);
953 	USETW(req.wIndex, reg);
954 	USETW(req.wLength, UMCS7840_READ_LENGTH);
955 
956 	err = usbd_do_request_proc(sc->sc_udev, &sc->sc_super_ucom.sc_tq, &req, (void *)data, 0, &len, UMCS7840_CTRL_TIMEOUT);
957 	if (err == USB_ERR_NORMAL_COMPLETION && len != 1) {
958 		device_printf(sc->sc_dev, "Reading register %d failed: invalid length %d\n", reg, len);
959 		return (USB_ERR_INVAL);
960 	} else if (err)
961 		device_printf(sc->sc_dev, "Reading register %d failed: %s\n", reg, usbd_errstr(err));
962 	return (err);
963 }
964 
965 static usb_error_t
966 umcs7840_set_reg_sync(struct umcs7840_softc *sc, uint8_t reg, uint8_t data)
967 {
968 	struct usb_device_request req;
969 	usb_error_t err;
970 
971 	req.bmRequestType = UT_WRITE_VENDOR_DEVICE;
972 	req.bRequest = MCS7840_WRREQ;
973 	USETW(req.wValue, data);
974 	USETW(req.wIndex, reg);
975 	USETW(req.wLength, 0);
976 
977 	err = usbd_do_request_proc(sc->sc_udev, &sc->sc_super_ucom.sc_tq, &req, NULL, 0, NULL, UMCS7840_CTRL_TIMEOUT);
978 	if (err)
979 		device_printf(sc->sc_dev, "Writing register %d failed: %s\n", reg, usbd_errstr(err));
980 
981 	return (err);
982 }
983 
984 static usb_error_t
985 umcs7840_get_UART_reg_sync(struct umcs7840_softc *sc, uint8_t portno, uint8_t reg, uint8_t *data)
986 {
987 	struct usb_device_request req;
988 	uint16_t wVal;
989 	usb_error_t err;
990 	uint16_t len;
991 
992 	/* portno is port number */
993 	wVal = ((uint16_t)(portno + 1)) << 8;
994 
995 	req.bmRequestType = UT_READ_VENDOR_DEVICE;
996 	req.bRequest = MCS7840_RDREQ;
997 	USETW(req.wValue, wVal);
998 	USETW(req.wIndex, reg);
999 	USETW(req.wLength, UMCS7840_READ_LENGTH);
1000 
1001 	err = usbd_do_request_proc(sc->sc_udev, &sc->sc_super_ucom.sc_tq, &req, (void *)data, 0, &len, UMCS7840_CTRL_TIMEOUT);
1002 	if (err == USB_ERR_NORMAL_COMPLETION && len != 1) {
1003 		device_printf(sc->sc_dev, "Reading UART%d register %d failed: invalid length %d\n", portno, reg, len);
1004 		return (USB_ERR_INVAL);
1005 	} else if (err)
1006 		device_printf(sc->sc_dev, "Reading UART%d register %d failed: %s\n", portno, reg, usbd_errstr(err));
1007 	return (err);
1008 }
1009 
1010 static usb_error_t
1011 umcs7840_set_UART_reg_sync(struct umcs7840_softc *sc, uint8_t portno, uint8_t reg, uint8_t data)
1012 {
1013 	struct usb_device_request req;
1014 	usb_error_t err;
1015 	uint16_t wVal;
1016 
1017 	/* portno is port number */
1018 	wVal = ((uint16_t)(portno + 1)) << 8 | data;
1019 
1020 	req.bmRequestType = UT_WRITE_VENDOR_DEVICE;
1021 	req.bRequest = MCS7840_WRREQ;
1022 	USETW(req.wValue, wVal);
1023 	USETW(req.wIndex, reg);
1024 	USETW(req.wLength, 0);
1025 
1026 	err = usbd_do_request_proc(sc->sc_udev, &sc->sc_super_ucom.sc_tq, &req, NULL, 0, NULL, UMCS7840_CTRL_TIMEOUT);
1027 	if (err)
1028 		device_printf(sc->sc_dev, "Writing UART%d register %d failed: %s\n", portno, reg, usbd_errstr(err));
1029 	return (err);
1030 }
1031 
1032 static usb_error_t
1033 umcs7840_set_baudrate(struct umcs7840_softc *sc, uint8_t portno, uint32_t rate)
1034 {
1035 	usb_error_t err;
1036 	uint16_t divisor;
1037 	uint8_t clk;
1038 	uint8_t data;
1039 
1040 	if (umcs7840_calc_baudrate(rate, &divisor, &clk)) {
1041 		DPRINTF("Port %d bad speed: %d\n", portno, rate);
1042 		return (-1);
1043 	}
1044 	if (divisor == 0 || (clk & MCS7840_DEV_SPx_CLOCK_MASK) != clk) {
1045 		DPRINTF("Port %d bad speed calculation: %d\n", portno, rate);
1046 		return (-1);
1047 	}
1048 	DPRINTF("Port %d set speed: %d (%02x / %d)\n", portno, rate, clk, divisor);
1049 
1050 	/* Set clock source for standard BAUD frequences */
1051 	err = umcs7840_get_reg_sync(sc, umcs7840_port_registers[portno].reg_sp, &data);
1052 	if (err)
1053 		return (err);
1054 	data &= MCS7840_DEV_SPx_CLOCK_MASK;
1055 	data |= clk;
1056 	err = umcs7840_set_reg_sync(sc, umcs7840_port_registers[portno].reg_sp, data);
1057 	if (err)
1058 		return (err);
1059 
1060 	/* Set divider */
1061 	sc->sc_ports[portno].sc_lcr |= MCS7840_UART_LCR_DIVISORS;
1062 	err = umcs7840_set_UART_reg_sync(sc, portno, MCS7840_UART_REG_LCR, sc->sc_ports[portno].sc_lcr);
1063 	if (err)
1064 		return (err);
1065 
1066 	err = umcs7840_set_UART_reg_sync(sc, portno, MCS7840_UART_REG_DLL, (uint8_t)(divisor & 0xff));
1067 	if (err)
1068 		return (err);
1069 	err = umcs7840_set_UART_reg_sync(sc, portno, MCS7840_UART_REG_DLM, (uint8_t)((divisor >> 8) & 0xff));
1070 	if (err)
1071 		return (err);
1072 
1073 	/* Turn off access to DLL/DLM registers of UART */
1074 	sc->sc_ports[portno].sc_lcr &= ~MCS7840_UART_LCR_DIVISORS;
1075 	err = umcs7840_set_UART_reg_sync(sc, portno, MCS7840_UART_REG_LCR, sc->sc_ports[portno].sc_lcr);
1076 	if (err)
1077 		return (err);
1078 	return (0);
1079 }
1080 
1081 /* Maximum speeds for standard frequences, when PLL is not used */
1082 static const uint32_t umcs7840_baudrate_divisors[] = {0, 115200, 230400, 403200, 460800, 806400, 921600, 1572864, 3145728,};
1083 static const uint8_t umcs7840_baudrate_divisors_len = nitems(umcs7840_baudrate_divisors);
1084 
1085 static usb_error_t
1086 umcs7840_calc_baudrate(uint32_t rate, uint16_t *divisor, uint8_t *clk)
1087 {
1088 	uint8_t i = 0;
1089 
1090 	if (rate > umcs7840_baudrate_divisors[umcs7840_baudrate_divisors_len - 1])
1091 		return (-1);
1092 
1093 	for (i = 0; i < umcs7840_baudrate_divisors_len - 1 &&
1094 	    !(rate > umcs7840_baudrate_divisors[i] && rate <= umcs7840_baudrate_divisors[i + 1]); ++i);
1095 	if (rate == 0)
1096 		*divisor = 1;	/* XXX */
1097 	else
1098 		*divisor = umcs7840_baudrate_divisors[i + 1] / rate;
1099 	/* 0x00 .. 0x70 */
1100 	*clk = i << MCS7840_DEV_SPx_CLOCK_SHIFT;
1101 	return (0);
1102 }
1103