1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2023 Arm Ltd
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/cdefs.h>
29#include <sys/param.h>
30#include <sys/systm.h>
31#include <sys/bus.h>
32#include <sys/cpu.h>
33#include <sys/kernel.h>
34#include <sys/module.h>
35
36#include <dev/fdt/simplebus.h>
37#include <dev/fdt/fdt_common.h>
38#include <dev/ofw/ofw_bus_subr.h>
39
40#include <dev/virtio/scmi/virtio_scmi.h>
41
42#include "scmi.h"
43#include "scmi_protocols.h"
44
45#define SCMI_VIRTIO_POLLING_INTERVAL_MS	2
46
47struct scmi_virtio_softc {
48	struct scmi_softc	base;
49	device_t		virtio_dev;
50	int			cmdq_sz;
51	int			evtq_sz;
52	void			*p2a_pool;
53};
54
55static void	scmi_virtio_callback(void *, unsigned int, void *);
56static void	*scmi_virtio_p2a_pool_init(device_t, unsigned int);
57static int	scmi_virtio_transport_init(device_t);
58static void	scmi_virtio_transport_cleanup(device_t);
59static int	scmi_virtio_xfer_msg(device_t, struct scmi_msg *);
60static int	scmi_virtio_poll_msg(device_t, struct scmi_msg *, unsigned int);
61static void	scmi_virtio_clear_channel(device_t, void *);
62static int	scmi_virtio_probe(device_t);
63static int	scmi_virtio_attach(device_t);
64
65static void
66scmi_virtio_callback(void *msg, unsigned int len, void *priv)
67{
68	struct scmi_virtio_softc *sc;
69	uint32_t hdr;
70
71	sc = priv;
72
73	if (msg == NULL || len < sizeof(hdr)) {
74		device_printf(sc->virtio_dev, "Ignoring malformed message.\n");
75		return;
76	}
77
78	hdr = le32toh(*((uint32_t *)msg));
79	scmi_rx_irq_callback(sc->base.dev, msg, hdr);
80}
81
82static void *
83scmi_virtio_p2a_pool_init(device_t dev, unsigned int max_msg)
84{
85	struct scmi_virtio_softc *sc;
86	void *pool;
87	uint8_t *buf;
88	int i;
89
90	sc = device_get_softc(dev);
91
92	pool = mallocarray(max_msg, SCMI_MAX_MSG_SIZE, M_DEVBUF,
93	    M_ZERO | M_WAITOK);
94
95	for (i = 0, buf = pool; i < max_msg; i++, buf += SCMI_MAX_MSG_SIZE) {
96		/* Feed platform with pre-allocated P2A buffers */
97		virtio_scmi_message_enqueue(sc->virtio_dev,
98		    VIRTIO_SCMI_CHAN_P2A, buf, 0, SCMI_MAX_MSG_SIZE);
99	}
100
101	device_printf(dev,
102	    "Fed %d initial P2A buffers to platform.\n", max_msg);
103
104	return (pool);
105}
106
107static void
108scmi_virtio_clear_channel(device_t dev, void *msg)
109{
110	struct scmi_virtio_softc *sc;
111
112	sc = device_get_softc(dev);
113	virtio_scmi_message_enqueue(sc->virtio_dev, VIRTIO_SCMI_CHAN_P2A,
114	    msg, 0, SCMI_MAX_MSG_SIZE);
115}
116
117static int
118scmi_virtio_transport_init(device_t dev)
119{
120	struct scmi_virtio_softc *sc;
121	int ret;
122
123	sc = device_get_softc(dev);
124
125	sc->cmdq_sz = virtio_scmi_channel_size_get(sc->virtio_dev,
126	    VIRTIO_SCMI_CHAN_A2P);
127	sc->evtq_sz = virtio_scmi_channel_size_get(sc->virtio_dev,
128	    VIRTIO_SCMI_CHAN_P2A);
129
130	if (!sc->cmdq_sz) {
131		device_printf(dev,
132		    "VirtIO cmdq virtqueue not found. Aborting.\n");
133		return (ENXIO);
134	}
135
136	/*
137	 * P2A buffers are owned by the platform initially; allocate a feed an
138	 * appropriate number of buffers.
139	 */
140	if (sc->evtq_sz != 0) {
141		sc->p2a_pool = scmi_virtio_p2a_pool_init(dev, sc->evtq_sz);
142		if (sc->p2a_pool == NULL)
143			return (ENOMEM);
144	}
145
146	/* Note that setting a callback also enables that VQ interrupts */
147	ret = virtio_scmi_channel_callback_set(sc->virtio_dev,
148	    VIRTIO_SCMI_CHAN_A2P, scmi_virtio_callback, sc);
149	if (ret) {
150		device_printf(dev, "Failed to set VirtIO cmdq callback.\n");
151		return (ENXIO);
152	}
153
154	device_printf(dev,
155	    "VirtIO cmdq virtqueue configured - cmdq_sz:%d\n", sc->cmdq_sz);
156
157	/* P2A channel is optional */
158	if (sc->evtq_sz) {
159		ret = virtio_scmi_channel_callback_set(sc->virtio_dev,
160		    VIRTIO_SCMI_CHAN_P2A, scmi_virtio_callback, sc);
161		if (ret == 0) {
162			device_printf(dev,
163			    "VirtIO evtq virtqueue configured - evtq_sz:%d\n",
164			    sc->evtq_sz);
165		} else {
166			device_printf(dev,
167			    "Failed to set VirtIO evtq callback.Skip.\n");
168			sc->evtq_sz = 0;
169		}
170	}
171
172	sc->base.trs_desc.reply_timo_ms = 100;
173
174	return (0);
175}
176
177static void
178scmi_virtio_transport_cleanup(device_t dev)
179{
180	struct scmi_virtio_softc *sc;
181
182	sc = device_get_softc(dev);
183
184	if (sc->evtq_sz != 0) {
185		virtio_scmi_channel_callback_set(sc->virtio_dev,
186		    VIRTIO_SCMI_CHAN_P2A, NULL, NULL);
187		free(sc->p2a_pool, M_DEVBUF);
188	}
189
190	virtio_scmi_channel_callback_set(sc->virtio_dev,
191	    VIRTIO_SCMI_CHAN_A2P, NULL, NULL);
192}
193
194static int
195scmi_virtio_xfer_msg(device_t dev, struct scmi_msg *msg)
196{
197	struct scmi_virtio_softc *sc;
198
199	sc = device_get_softc(dev);
200
201	return (virtio_scmi_message_enqueue(sc->virtio_dev,
202	    VIRTIO_SCMI_CHAN_A2P, &msg->hdr, msg->tx_len, msg->rx_len));
203}
204
205static int
206scmi_virtio_poll_msg(device_t dev, struct scmi_msg *msg, unsigned int tmo_ms)
207{
208	struct scmi_virtio_softc *sc;
209	device_t vdev;
210	int tmo_loops;
211
212	sc = device_get_softc(dev);
213	vdev = sc->virtio_dev;
214
215	tmo_loops = tmo_ms / SCMI_VIRTIO_POLLING_INTERVAL_MS;
216	while (tmo_loops-- && atomic_load_acq_int(&msg->poll_done) == 0) {
217		struct scmi_msg *rx_msg;
218		void *rx_buf;
219		uint32_t rx_len;
220
221		rx_buf = virtio_scmi_message_poll(vdev, &rx_len);
222		if (rx_buf == NULL) {
223			DELAY(SCMI_VIRTIO_POLLING_INTERVAL_MS * 1000);
224			continue;
225		}
226
227		rx_msg = hdr_to_msg(rx_buf);
228		rx_msg->rx_len = rx_len;
229		/* Complete the polling on any poll path */
230		if (rx_msg->polling)
231			atomic_store_rel_int(&rx_msg->poll_done, 1);
232
233		if (__predict_true(rx_msg == msg))
234			break;
235
236		/*
237		 * Polling returned an unexpected message: either a message
238		 * polled by some other thread of execution or a message not
239		 * supposed to be polled.
240		 */
241		device_printf(dev, "POLLED OoO HDR:|%08X| - polling:%d\n",
242		    rx_msg->hdr, rx_msg->polling);
243
244		if (!rx_msg->polling)
245			scmi_rx_irq_callback(sc->base.dev, rx_msg, rx_msg->hdr);
246	}
247
248	return (tmo_loops > 0 ? 0 : ETIMEDOUT);
249}
250
251static int
252scmi_virtio_probe(device_t dev)
253{
254	if (!ofw_bus_is_compatible(dev, "arm,scmi-virtio"))
255		return (ENXIO);
256
257	if (!ofw_bus_status_okay(dev))
258		return (ENXIO);
259
260	device_set_desc(dev, "ARM SCMI VirtIO Transport driver");
261
262	return (BUS_PROBE_DEFAULT);
263}
264
265static int
266scmi_virtio_attach(device_t dev)
267{
268	struct scmi_virtio_softc *sc;
269
270	sc = device_get_softc(dev);
271	sc->virtio_dev = virtio_scmi_transport_get();
272	if (sc->virtio_dev == NULL)
273		return (1);
274
275	/* When attach fails there is nothing to cleanup*/
276	return (scmi_attach(dev));
277}
278
279static device_method_t scmi_virtio_methods[] = {
280	DEVMETHOD(device_probe,		scmi_virtio_probe),
281	DEVMETHOD(device_attach,	scmi_virtio_attach),
282
283	/* SCMI interface */
284	DEVMETHOD(scmi_transport_init,		scmi_virtio_transport_init),
285	DEVMETHOD(scmi_transport_cleanup,	scmi_virtio_transport_cleanup),
286	DEVMETHOD(scmi_xfer_msg,		scmi_virtio_xfer_msg),
287	DEVMETHOD(scmi_poll_msg,		scmi_virtio_poll_msg),
288	DEVMETHOD(scmi_clear_channel,		scmi_virtio_clear_channel),
289
290	DEVMETHOD_END
291};
292
293DEFINE_CLASS_1(scmi_virtio, scmi_virtio_driver, scmi_virtio_methods,
294    sizeof(struct scmi_virtio_softc), scmi_driver);
295
296/* Needs to be after the mmio_sram driver */
297DRIVER_MODULE(scmi_virtio, simplebus, scmi_virtio_driver, 0, 0);
298MODULE_VERSION(scmi_virtio, 1);
299