Add a driver to talk to the Raspberry Pi firmware

Communicating with the Raspberry Pi firmware is currently handled by each
driver calling into the mbox driver, however the device tree is structured
such that they should be calling into a firmware driver.

Add a driver for this node with an interface to communicate to the firmware
via the mbox interface.

There is a sysctl to get the firmware revision. This is a unix date so can
be parsed with:

root@generic:~ # date -j -f '%s' sysctl -n dev.bcm2835_firmware.0.revision
Tue Nov 19 16:40:28 UTC 2019

Reviewed by:	manu
Sponsored by:	Innovate UK
Differential Revision:	https://reviews.freebsd.org/D25572

4 files changed, 224 insertions, 0 deletions

diff --git a/sys/arm/broadcom/bcm2835/bcm2835_firmware.c b/sys/arm/broadcom/bcm2835/bcm2835_firmware.c
new file mode 100644
index 000000000000..dcc23fe1cd61
--- /dev/null
+++ b/sys/arm/broadcom/bcm2835/bcm2835_firmware.c
@@ -0,0 +1,181 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2020 Andrew Turner
+ *
+ * This work was supported by Innovate UK project 105694, "Digital Security
+ * by Design (DSbD) Technology Platform Prototype".
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/bus.h>
+#include <sys/kernel.h>
+#include <sys/module.h>
+#include <sys/sysctl.h>
+
+#include <dev/ofw/ofw_bus.h>
+#include <dev/ofw/ofw_bus_subr.h>
+
+#include <arm/broadcom/bcm2835/bcm2835_firmware.h>
+#include <arm/broadcom/bcm2835/bcm2835_mbox.h>
+#include <arm/broadcom/bcm2835/bcm2835_mbox_prop.h>
+#include <arm/broadcom/bcm2835/bcm2835_vcbus.h>
+
+struct bcm2835_firmware_softc {
+	device_t	sc_dev;
+	phandle_t	sc_mbox;
+};
+
+static struct ofw_compat_data compat_data[] = {
+	{"raspberrypi,bcm2835-firmware",	1},
+	{NULL,					0}
+};
+
+static int sysctl_bcm2835_firmware_get_revision(SYSCTL_HANDLER_ARGS);
+
+static int
+bcm2835_firmware_probe(device_t dev)
+{
+	if (!ofw_bus_status_okay(dev))
+		return (ENXIO);
+
+	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
+		return (ENXIO);
+
+	device_set_desc(dev, "BCM2835 Firmware");
+	return (BUS_PROBE_DEFAULT);
+}
+
+static int
+bcm2835_firmware_attach(device_t dev)
+{
+	struct bcm2835_firmware_softc *sc;
+	struct sysctl_ctx_list *ctx;
+	struct sysctl_oid *tree_node;
+	struct sysctl_oid_list *tree;
+	phandle_t node, mbox;
+	int rv;
+
+	sc = device_get_softc(dev);
+	sc->sc_dev = dev;
+
+	node = ofw_bus_get_node(dev);
+	rv = OF_getencprop(node, "mboxes", &mbox, sizeof(mbox));
+	if (rv <= 0) {
+		device_printf(dev, "can't read mboxes property\n");
+		return (ENXIO);
+	}
+	sc->sc_mbox = mbox;
+
+	OF_device_register_xref(OF_xref_from_node(node), dev);
+
+	ctx = device_get_sysctl_ctx(sc->sc_dev);
+	tree_node = device_get_sysctl_tree(sc->sc_dev);
+	tree = SYSCTL_CHILDREN(tree_node);
+	SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "revision",
+	    CTLTYPE_UINT | CTLFLAG_RD, sc, sizeof(*sc),
+	    sysctl_bcm2835_firmware_get_revision, "IU",
+	    "Firmware revision");
+	return (0);
+}
+
+int
+bcm2835_firmware_property(device_t dev, uint32_t prop, void *data, size_t len)
+{
+	struct {
+		struct bcm2835_mbox_hdr hdr;
+		struct bcm2835_mbox_tag_hdr tag_hdr;
+		uint32_t data[];
+	} *msg_hdr;
+	size_t msg_len;
+	int err;
+
+	/*
+	 * The message is processed in 32-bit chunks so must be a multiple
+	 * of 32-bits.
+	 */
+	if ((len & (sizeof(uint32_t) - 1)) != 0)
+		return (EINVAL);
+
+	msg_len = sizeof(*msg_hdr) + len + sizeof(uint32_t);
+	msg_hdr = malloc(sizeof(*msg_hdr) + msg_len + sizeof(uint32_t),
+	    M_DEVBUF, M_WAITOK | M_ZERO);
+
+	msg_hdr->hdr.buf_size = msg_len;
+	msg_hdr->hdr.code = BCM2835_MBOX_CODE_REQ;
+	msg_hdr->tag_hdr.tag = prop;
+	msg_hdr->tag_hdr.val_buf_size = len;
+	memcpy(msg_hdr->data, data, len);
+	msg_hdr->data[len / sizeof(uint32_t)] = 0;
+
+	err = bcm2835_mbox_property(msg_hdr, msg_len);
+	if (err == 0) {
+		memcpy(data, msg_hdr->data, len);
+	}
+
+	free(msg_hdr, M_DEVBUF);
+
+	return (err);
+}
+
+static int
+sysctl_bcm2835_firmware_get_revision(SYSCTL_HANDLER_ARGS)
+{
+	struct bcm2835_firmware_softc *sc = arg1;
+	uint32_t rev;
+	int err;
+
+	if (bcm2835_firmware_property(sc->sc_dev,
+	    BCM2835_MBOX_TAG_FIRMWARE_REVISION, &rev, sizeof(rev)) != 0)
+		return (ENXIO);
+
+	err = sysctl_handle_int(oidp, &rev, sizeof(rev), req);
+	if (err || !req->newptr) /* error || read request */
+		return (err);
+
+	/* write request */
+	return (EINVAL);
+}
+
+static device_method_t bcm2835_firmware_methods[] = {
+	/* Device interface */
+	DEVMETHOD(device_probe,		bcm2835_firmware_probe),
+	DEVMETHOD(device_attach,	bcm2835_firmware_attach),
+
+	DEVMETHOD_END
+};
+
+static devclass_t bcm2835_firmware_devclass;
+static driver_t bcm2835_firmware_driver = {
+	"bcm2835_firmware",
+	bcm2835_firmware_methods,
+	sizeof(struct bcm2835_firmware_softc),
+};
+
+DRIVER_MODULE(bcm2835_firmware, simplebus, bcm2835_firmware_driver,
+    bcm2835_firmware_devclass, 0, 0);
diff --git a/sys/arm/broadcom/bcm2835/bcm2835_firmware.h b/sys/arm/broadcom/bcm2835/bcm2835_firmware.h
new file mode 100644
index 000000000000..da6a137083ed
--- /dev/null
+++ b/sys/arm/broadcom/bcm2835/bcm2835_firmware.h
@@ -0,0 +1,38 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2020 Andrew Turner
+ *
+ * This work was supported by Innovate UK project 105694, "Digital Security
+ * by Design (DSbD) Technology Platform Prototype".
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _BCM2835_FIRMWARE_H_
+#define _BCM2835_FIRMWARE_H_
+
+int bcm2835_firmware_property(device_t, uint32_t, void *, size_t);
+
+#endif
diff --git a/sys/arm/broadcom/bcm2835/bcm2835_mbox_prop.h b/sys/arm/broadcom/bcm2835/bcm2835_mbox_prop.h
index c2dfc4975865..211820c09c31 100644
--- a/sys/arm/broadcom/bcm2835/bcm2835_mbox_prop.h
+++ b/sys/arm/broadcom/bcm2835/bcm2835_mbox_prop.h
@@ -58,6 +58,10 @@ struct bcm2835_mbox_tag_hdr {
 	(tag_)->tag_hdr.val_len = sizeof((tag_)->body.req);	\
 } while (0)
 
+#define BCM2835_MBOX_TAG_FIRMWARE_REVISION	0x00000001
+
+
+
 #define BCM2835_MBOX_POWER_ID_EMMC		0x00000000
 #define BCM2835_MBOX_POWER_ID_UART0		0x00000001
 #define BCM2835_MBOX_POWER_ID_UART1		0x00000002
diff --git a/sys/arm/broadcom/bcm2835/files.bcm283x b/sys/arm/broadcom/bcm2835/files.bcm283x
index f367d46a018f..d4faae8e338c 100644
--- a/sys/arm/broadcom/bcm2835/files.bcm283x
+++ b/sys/arm/broadcom/bcm2835/files.bcm283x
@@ -5,6 +5,7 @@ arm/broadcom/bcm2835/bcm2835_cpufreq.c		standard
 arm/broadcom/bcm2835/bcm2835_dma.c		standard
 arm/broadcom/bcm2835/bcm2835_fb.c		optional sc
 arm/broadcom/bcm2835/bcm2835_fbd.c		optional vt
+arm/broadcom/bcm2835/bcm2835_firmware.c		standard
 arm/broadcom/bcm2835/bcm2835_ft5406.c		optional evdev bcm2835_ft5406
 arm/broadcom/bcm2835/bcm2835_gpio.c		optional gpio
 arm/broadcom/bcm2835/bcm2835_intr.c		standard