1/*-
2 * Copyright (c) 2014 Ruslan Bukin <br@bsdpad.com>
3 * All rights reserved.
4 *
5 * This software was developed by SRI International and the University of
6 * Cambridge Computer Laboratory under DARPA/AFRL contract (FA8750-10-C-0237)
7 * ("CTSRD"), as part of the DARPA CRASH research programme.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31/*
32 * SRI-Cambridge BERI soft processor <-> ARM core ring buffer.
33 */
34
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD$");
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/bus.h>
41#include <sys/kernel.h>
42#include <sys/module.h>
43#include <sys/malloc.h>
44#include <sys/rman.h>
45#include <sys/timeet.h>
46#include <sys/timetc.h>
47#include <sys/conf.h>
48#include <sys/uio.h>
49#include <sys/stat.h>
50#include <sys/time.h>
51#include <sys/event.h>
52#include <sys/selinfo.h>
53
54#include <dev/fdt/fdt_common.h>
55#include <dev/ofw/openfirm.h>
56#include <dev/ofw/ofw_bus.h>
57#include <dev/ofw/ofw_bus_subr.h>
58
59#include <machine/bus.h>
60#include <machine/fdt.h>
61#include <machine/cpu.h>
62#include <machine/intr.h>
63
64#define READ4(_sc, _reg) \
65	bus_read_4((_sc)->res[0], _reg)
66#define WRITE4(_sc, _reg, _val) \
67	bus_write_4((_sc)->res[0], _reg, _val)
68
69#define CDES_INT_EN		(1 << 15)
70#define CDES_CAUSE_MASK		0x3
71#define CDES_CAUSE_SHIFT	13
72#define DEVNAME_MAXLEN		256
73
74typedef struct
75{
76	uint16_t cdes;
77	uint16_t interrupt_level;
78	uint16_t in;
79	uint16_t out;
80} control_reg_t;
81
82struct beri_softc {
83	struct resource		*res[3];
84	bus_space_tag_t		bst;
85	bus_space_handle_t	bsh;
86	struct cdev		*cdev;
87	device_t		dev;
88	void			*read_ih;
89	void			*write_ih;
90	struct selinfo		beri_rsel;
91	struct mtx		beri_mtx;
92	int			opened;
93
94	char			devname[DEVNAME_MAXLEN];
95	int			control_read;
96	int			control_write;
97	int			data_read;
98	int			data_write;
99	int			data_size;
100};
101
102static struct resource_spec beri_spec[] = {
103	{ SYS_RES_MEMORY,	0,	RF_ACTIVE },
104	{ SYS_RES_IRQ,		0,	RF_ACTIVE },
105	{ SYS_RES_IRQ,		1,	RF_ACTIVE },
106	{ -1, 0 }
107};
108
109static control_reg_t
110get_control_reg(struct beri_softc *sc, int dir)
111{
112	uint32_t offset;
113	uint16_t dst[4];
114	control_reg_t c;
115	uint16_t *cp;
116	int i;
117
118	cp = (uint16_t *)&c;
119
120	offset = dir ? sc->control_write : sc->control_read;
121	((uint32_t *)dst)[0] = READ4(sc, offset);
122	((uint32_t *)dst)[1] = READ4(sc, offset + 4);
123
124	for (i = 0; i < 4; i++)
125		cp[i] = dst[3 - i];
126
127	return (c);
128}
129
130static void
131set_control_reg(struct beri_softc *sc, int dir, control_reg_t *c)
132{
133	uint32_t offset;
134	uint16_t src[4];
135	uint16_t *cp;
136	int i;
137
138	cp = (uint16_t *)c;
139
140	for (i = 0; i < 4; i++)
141		src[3 - i] = cp[i];
142
143	offset = dir ? sc->control_write : sc->control_read;
144	WRITE4(sc, offset + 0, ((uint32_t *)src)[0]);
145	WRITE4(sc, offset + 4, ((uint32_t *)src)[1]);
146}
147
148static int
149get_stock(struct beri_softc *sc, int dir, control_reg_t *c)
150{
151	uint32_t fill;
152
153	fill = (c->in - c->out + sc->data_size) % sc->data_size;
154
155	if (dir)
156		return (sc->data_size - fill - 1);
157	else
158		return (fill);
159}
160
161static void
162beri_intr_write(void *arg)
163{
164	struct beri_softc *sc;
165	control_reg_t c;
166
167	sc = arg;
168
169	c = get_control_reg(sc, 1);
170	if (c.cdes & CDES_INT_EN) {
171		c.cdes &= ~(CDES_INT_EN);
172		set_control_reg(sc, 1, &c);
173	}
174
175	mtx_lock(&sc->beri_mtx);
176	selwakeuppri(&sc->beri_rsel, PZERO + 1);
177	KNOTE_LOCKED(&sc->beri_rsel.si_note, 0);
178	mtx_unlock(&sc->beri_mtx);
179}
180
181static void
182beri_intr_read(void *arg)
183{
184	struct beri_softc *sc;
185	control_reg_t c;
186
187	sc = arg;
188
189	c = get_control_reg(sc, 0);
190	if (c.cdes & CDES_INT_EN) {
191		c.cdes &= ~(CDES_INT_EN);
192		set_control_reg(sc, 0, &c);
193	}
194
195	mtx_lock(&sc->beri_mtx);
196	selwakeuppri(&sc->beri_rsel, PZERO + 1);
197	KNOTE_LOCKED(&sc->beri_rsel.si_note, 0);
198	mtx_unlock(&sc->beri_mtx);
199}
200
201static int
202beri_open(struct cdev *dev, int flags __unused,
203    int fmt __unused, struct thread *td __unused)
204{
205	struct beri_softc *sc;
206	control_reg_t c;
207
208	sc = dev->si_drv1;
209
210	if (sc->opened)
211		return (1);
212
213	/* Setup interrupt handlers */
214	if (bus_setup_intr(sc->dev, sc->res[1], INTR_TYPE_BIO | INTR_MPSAFE,
215		NULL, beri_intr_read, sc, &sc->read_ih)) {
216		device_printf(sc->dev, "Unable to setup read intr\n");
217		return (1);
218	}
219	if (bus_setup_intr(sc->dev, sc->res[2], INTR_TYPE_BIO | INTR_MPSAFE,
220		NULL, beri_intr_write, sc, &sc->write_ih)) {
221		device_printf(sc->dev, "Unable to setup write intr\n");
222		return (1);
223	}
224
225	sc->opened = 1;
226
227	/* Clear write buffer */
228	c = get_control_reg(sc, 1);
229	c.in = c.out;
230	c.cdes = 0;
231	set_control_reg(sc, 1, &c);
232
233	/* Clear read buffer */
234	c = get_control_reg(sc, 0);
235	c.out = c.in;
236	c.cdes = 0;
237	set_control_reg(sc, 0, &c);
238
239	return (0);
240}
241
242static int
243beri_close(struct cdev *dev, int flags __unused,
244    int fmt __unused, struct thread *td __unused)
245{
246	struct beri_softc *sc;
247
248	sc = dev->si_drv1;
249
250	if (sc->opened) {
251		sc->opened = 0;
252
253		/* Unsetup interrupt handlers */
254		bus_teardown_intr(sc->dev, sc->res[1], sc->read_ih);
255		bus_teardown_intr(sc->dev, sc->res[2], sc->write_ih);
256	}
257
258	return (0);
259}
260
261static int
262beri_rdwr(struct cdev *dev, struct uio *uio, int ioflag)
263{
264	struct beri_softc *sc;
265	uint32_t offset;
266	control_reg_t c;
267	uint16_t *ptr;
268	uint8_t *dst;
269	int stock;
270	int dir;
271	int amount;
272	int count;
273
274	sc = dev->si_drv1;
275
276	dir = uio->uio_rw ? 1 : 0;
277
278	c = get_control_reg(sc, dir);
279	stock = get_stock(sc, dir, &c);
280	if (stock < uio->uio_resid) {
281		device_printf(sc->dev, "Err: no data/space available\n");
282		return (1);
283	}
284
285	amount = uio->uio_resid;
286	ptr = dir ? &c.in : &c.out;
287	count = (sc->data_size - *ptr);
288
289	offset = dir ? sc->data_write : sc->data_read;
290	dst = (uint8_t *)(sc->bsh + offset);
291
292	if (amount <= count) {
293		uiomove(dst + *ptr, amount, uio);
294	} else {
295		uiomove(dst + *ptr, count, uio);
296		uiomove(dst, (amount - count), uio);
297	}
298
299	*ptr = (*ptr + amount) % sc->data_size;
300	set_control_reg(sc, dir, &c);
301
302	return (0);
303}
304
305static int
306beri_kqread(struct knote *kn, long hint)
307{
308	struct beri_softc *sc;
309	control_reg_t c;
310	int stock;
311
312	sc = kn->kn_hook;
313
314	c = get_control_reg(sc, 0);
315	stock = get_stock(sc, 0, &c);
316	if (stock) {
317		kn->kn_data = stock;
318		return (1);
319	}
320
321	kn->kn_data = 0;
322
323	/* Wait at least one new byte in buffer */
324	c.interrupt_level = 1;
325
326	/* Enable interrupts */
327	c.cdes |= (CDES_INT_EN);
328	set_control_reg(sc, 0, &c);
329
330	return (0);
331}
332
333static int
334beri_kqwrite(struct knote *kn, long hint)
335{
336	struct beri_softc *sc;
337	control_reg_t c;
338	int stock;
339
340	sc = kn->kn_hook;
341
342	c = get_control_reg(sc, 1);
343	stock = get_stock(sc, 1, &c);
344	if (stock) {
345		kn->kn_data = stock;
346		return (1);
347	}
348
349	kn->kn_data = 0;
350
351	/* Wait at least one free position in buffer */
352	c.interrupt_level = sc->data_size - 2;
353
354	/* Enable interrupts */
355	c.cdes |= (CDES_INT_EN);
356	set_control_reg(sc, 1, &c);
357
358	return (0);
359}
360
361static void
362beri_kqdetach(struct knote *kn)
363{
364	struct beri_softc *sc;
365
366	sc = kn->kn_hook;
367
368	knlist_remove(&sc->beri_rsel.si_note, kn, 0);
369}
370
371static struct filterops beri_read_filterops = {
372	.f_isfd =       1,
373	.f_attach =     NULL,
374	.f_detach =     beri_kqdetach,
375	.f_event =      beri_kqread,
376};
377
378static struct filterops beri_write_filterops = {
379	.f_isfd =       1,
380	.f_attach =     NULL,
381	.f_detach =     beri_kqdetach,
382	.f_event =      beri_kqwrite,
383};
384
385static int
386beri_kqfilter(struct cdev *dev, struct knote *kn)
387{
388	struct beri_softc *sc;
389
390	sc = dev->si_drv1;
391
392	switch(kn->kn_filter) {
393	case EVFILT_READ:
394		kn->kn_fop = &beri_read_filterops;
395		break;
396	case EVFILT_WRITE:
397		kn->kn_fop = &beri_write_filterops;
398		break;
399	default:
400		return(EINVAL);
401	}
402
403	kn->kn_hook = sc;
404	knlist_add(&sc->beri_rsel.si_note, kn, 0);
405
406	return (0);
407}
408
409static struct cdevsw beri_cdevsw = {
410	.d_version =	D_VERSION,
411	.d_open =	beri_open,
412	.d_close =	beri_close,
413	.d_write =	beri_rdwr,
414	.d_read =	beri_rdwr,
415	.d_kqfilter =	beri_kqfilter,
416	.d_name =	"beri ring buffer",
417};
418
419static int
420parse_fdt(struct beri_softc *sc)
421{
422	pcell_t dts_value[0];
423	phandle_t node;
424	int len;
425
426	if ((node = ofw_bus_get_node(sc->dev)) == -1)
427		return (ENXIO);
428
429	/* get device name */
430	if (OF_getprop(ofw_bus_get_node(sc->dev), "device_name",
431		&sc->devname, sizeof(sc->devname)) <= 0) {
432		device_printf(sc->dev, "Can't get device_name\n");
433		return (ENXIO);
434	}
435
436	if ((len = OF_getproplen(node, "data_size")) <= 0)
437		return (ENXIO);
438	OF_getencprop(node, "data_size", dts_value, len);
439	sc->data_size = dts_value[0];
440
441	if ((len = OF_getproplen(node, "data_read")) <= 0)
442		return (ENXIO);
443	OF_getencprop(node, "data_read", dts_value, len);
444	sc->data_read = dts_value[0];
445
446	if ((len = OF_getproplen(node, "data_write")) <= 0)
447		return (ENXIO);
448	OF_getencprop(node, "data_write", dts_value, len);
449	sc->data_write = dts_value[0];
450
451	if ((len = OF_getproplen(node, "control_read")) <= 0)
452		return (ENXIO);
453	OF_getencprop(node, "control_read", dts_value, len);
454	sc->control_read = dts_value[0];
455
456	if ((len = OF_getproplen(node, "control_write")) <= 0)
457		return (ENXIO);
458	OF_getencprop(node, "control_write", dts_value, len);
459	sc->control_write = dts_value[0];
460
461	return (0);
462}
463
464static int
465beri_probe(device_t dev)
466{
467
468	if (!ofw_bus_status_okay(dev))
469		return (ENXIO);
470
471	if (!ofw_bus_is_compatible(dev, "sri-cambridge,beri-ring"))
472		return (ENXIO);
473
474	device_set_desc(dev, "SRI-Cambridge BERI ring buffer");
475	return (BUS_PROBE_DEFAULT);
476}
477
478static int
479beri_attach(device_t dev)
480{
481	struct beri_softc *sc;
482
483	sc = device_get_softc(dev);
484	sc->dev = dev;
485
486	if (bus_alloc_resources(dev, beri_spec, sc->res)) {
487		device_printf(dev, "could not allocate resources\n");
488		return (ENXIO);
489	}
490
491	/* Memory interface */
492	sc->bst = rman_get_bustag(sc->res[0]);
493	sc->bsh = rman_get_bushandle(sc->res[0]);
494
495	if (parse_fdt(sc)) {
496		device_printf(sc->dev, "Can't get FDT values\n");
497		return (ENXIO);
498	}
499
500	sc->cdev = make_dev(&beri_cdevsw, 0, UID_ROOT, GID_WHEEL,
501	    S_IRWXU, "%s", sc->devname);
502	if (sc->cdev == NULL) {
503		device_printf(dev, "Failed to create character device.\n");
504		return (ENXIO);
505	}
506
507	sc->cdev->si_drv1 = sc;
508
509	mtx_init(&sc->beri_mtx, "beri_mtx", NULL, MTX_DEF);
510	knlist_init_mtx(&sc->beri_rsel.si_note, &sc->beri_mtx);
511
512	return (0);
513}
514
515static device_method_t beri_methods[] = {
516	DEVMETHOD(device_probe,		beri_probe),
517	DEVMETHOD(device_attach,	beri_attach),
518	{ 0, 0 }
519};
520
521static driver_t beri_driver = {
522	"beri_ring",
523	beri_methods,
524	sizeof(struct beri_softc),
525};
526
527static devclass_t beri_devclass;
528
529DRIVER_MODULE(beri_ring, simplebus, beri_driver, beri_devclass, 0, 0);
530