1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2021 Jessica Clarke <jrtc27@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <sys/param.h>
29#include <sys/systm.h>
30#include <sys/bus.h>
31#include <sys/cpuset.h>
32#include <sys/kernel.h>
33#include <sys/module.h>
34#include <sys/rman.h>
35
36#include <machine/intr.h>
37#include <machine/sbi.h>
38#include <machine/smp.h>
39
40#include <dev/ofw/openfirm.h>
41#include <dev/ofw/ofw_bus.h>
42#include <dev/ofw/ofw_bus_subr.h>
43
44#include "pic_if.h"
45
46struct sbi_ipi_softc {
47	device_t		dev;
48	struct resource		*irq_res;
49	void			*ih;
50	struct intr_irqsrc	isrc;
51	uint32_t		pending_ipis[MAXCPU];
52};
53
54static void
55sbi_ipi_pic_ipi_send(device_t dev, struct intr_irqsrc *isrc, cpuset_t cpus,
56    u_int ipi)
57{
58	struct sbi_ipi_softc *sc;
59	struct pcpu *pc;
60	u_long mask;
61	u_int cpu;
62
63	sc = device_get_softc(dev);
64
65	KASSERT(isrc == &sc->isrc, ("%s: not the IPI isrc", __func__));
66	KASSERT(ipi < INTR_IPI_COUNT,
67	    ("%s: not a valid IPI: %u", __func__, ipi));
68
69	mask = 0;
70	STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
71		cpu = pc->pc_cpuid;
72		if (CPU_ISSET(cpu, &cpus)) {
73			atomic_set_32(&sc->pending_ipis[cpu], 1u << ipi);
74			mask |= (1ul << pc->pc_hart);
75		}
76	}
77	sbi_send_ipi(&mask);
78}
79
80static int
81sbi_ipi_pic_ipi_setup(device_t dev, u_int ipi, struct intr_irqsrc **isrcp)
82{
83	struct sbi_ipi_softc *sc;
84
85	sc = device_get_softc(dev);
86
87	KASSERT(ipi < INTR_IPI_COUNT,
88	    ("%s: not a valid IPI: %u", __func__, ipi));
89
90	*isrcp = &sc->isrc;
91
92	return (0);
93
94}
95
96static int
97sbi_ipi_intr(void *arg)
98{
99	struct sbi_ipi_softc *sc;
100	uint32_t ipi_bitmap;
101	u_int cpu, ipi;
102	int bit;
103
104	sc = arg;
105
106	csr_clear(sip, SIP_SSIP);
107
108	cpu = PCPU_GET(cpuid);
109
110	mb();
111
112	ipi_bitmap = atomic_readandclear_32(&sc->pending_ipis[cpu]);
113	if (ipi_bitmap == 0)
114		return (FILTER_HANDLED);
115
116	mb();
117
118	while ((bit = ffs(ipi_bitmap))) {
119		ipi = (bit - 1);
120		ipi_bitmap &= ~(1u << ipi);
121
122		intr_ipi_dispatch(ipi);
123	}
124
125	return (FILTER_HANDLED);
126}
127
128static int
129sbi_ipi_probe(device_t dev)
130{
131	device_set_desc(dev, "RISC-V SBI Inter-Processor Interrupts");
132
133	return (BUS_PROBE_NOWILDCARD);
134}
135
136static int
137sbi_ipi_attach(device_t dev)
138{
139	struct sbi_ipi_softc *sc;
140	const char *name;
141	int irq, rid, error;
142	phandle_t iparent;
143	pcell_t cell;
144
145	sc = device_get_softc(dev);
146	sc->dev = dev;
147
148	memset(sc->pending_ipis, 0, sizeof(sc->pending_ipis));
149
150	name = device_get_nameunit(dev);
151	error = intr_isrc_register(&sc->isrc, sc->dev, INTR_ISRCF_IPI,
152	    "%s,ipi", name);
153	if (error != 0) {
154		device_printf(dev, "Can't register interrupt: %d\n", error);
155		return (ENXIO);
156	}
157
158	iparent = OF_xref_from_node(ofw_bus_get_node(intr_irq_root_dev));
159	cell = IRQ_SOFTWARE_SUPERVISOR;
160	irq = ofw_bus_map_intr(dev, iparent, 1, &cell);
161	error = bus_set_resource(dev, SYS_RES_IRQ, 0, irq, 1);
162	if (error != 0) {
163		device_printf(dev, "Unable to register IRQ resource\n");
164		return (ENXIO);
165	}
166
167	rid = 0;
168	sc->irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
169	    RF_ACTIVE | RF_SHAREABLE);
170	if (sc->irq_res == NULL) {
171		device_printf(dev, "Unable to alloc IRQ resource\n");
172		return (ENXIO);
173	}
174
175	error = bus_setup_intr(dev, sc->irq_res, INTR_TYPE_CLK,
176	    sbi_ipi_intr, NULL, sc, &sc->ih);
177	if (error != 0) {
178		device_printf(dev, "Unable to setup IRQ resource\n");
179		return (ENXIO);
180	}
181
182	/* TODO: Define a set of priorities once other IPI sources exist */
183	error = intr_ipi_pic_register(dev, 0);
184	if (error != 0) {
185		device_printf(dev, "Can't register as IPI source: %d\n", error);
186		return (ENXIO);
187	}
188
189	return (0);
190}
191
192static device_method_t sbi_ipi_methods[] = {
193	/* Device interface */
194	DEVMETHOD(device_probe,		sbi_ipi_probe),
195	DEVMETHOD(device_attach,	sbi_ipi_attach),
196
197	/* Interrupt controller interface */
198	DEVMETHOD(pic_ipi_send,		sbi_ipi_pic_ipi_send),
199	DEVMETHOD(pic_ipi_setup,	sbi_ipi_pic_ipi_setup),
200
201	DEVMETHOD_END
202};
203
204DEFINE_CLASS_0(sbi_ipi, sbi_ipi_driver, sbi_ipi_methods,
205    sizeof(struct sbi_ipi_softc));
206/* Local interrupt controller attaches during BUS_PASS_ORDER_FIRST */
207EARLY_DRIVER_MODULE(sbi_ipi, sbi, sbi_ipi_driver, 0, 0,
208    BUS_PASS_INTERRUPT + BUS_PASS_ORDER_EARLY);
209