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diff --git a/sys/arm/broadcom/bcm2835/bcm2835_firmware.h b/sys/arm/broadcom/bcm2835/bcm2835_firmware.h
--- a/sys/arm/broadcom/bcm2835/bcm2835_firmware.h
+++ b/sys/arm/broadcom/bcm2835/bcm2835_firmware.h
@@ -195,6 +195,18 @@
} resp;
};
+#define BCM2835_FIRMWARE_TAG_GET_GPIOVIRTBUF 0x00040010
+#define BCM2835_FIRMWARE_TAG_SET_GPIOVIRTBUF 0x00048020
+
+union msg_gpiovirtbuf {
+ struct {
+ uint32_t addr;
+ } req;
+ struct {
+ uint32_t addr;
+ } resp;
+};
+
int bcm2835_firmware_property(device_t, uint32_t, void *, size_t);
#endif
diff --git a/sys/arm/broadcom/bcm2835/raspberrypi_virtgpio.c b/sys/arm/broadcom/bcm2835/raspberrypi_virtgpio.c
new file mode 100644
--- /dev/null
+++ b/sys/arm/broadcom/bcm2835/raspberrypi_virtgpio.c
@@ -0,0 +1,346 @@
+/* -
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2025 Tetsuya Uemura <t_uemura@macome.co.jp>
+ *
+ * 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.
+ */
+
+/*
+ * This is a driver for bcm2835-virtgpio GPIO controller device found on some
+ * Raspberry Pi models (listed below but not limited to). On which, the green
+ * LED (ACT) is connected to this controller. With the help of this driver, a
+ * node corresponding to the green LED will be created under /dev/led, allowing
+ * us to control it.
+ *
+ * Applicable models (according to the FDTs of those models):
+ * Compute Module 2 (CM2)
+ * 3 Model B (not 3B+)
+ * Compute Module 3 (CM3) and possibly 3+ (CM3+)
+ * Compute Module 4 SODIMM (CM4S)
+ */
+
+#include "opt_platform.h"
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/gpio.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <sys/module.h>
+#include <sys/mutex.h>
+
+#include <vm/vm.h>
+#include <vm/pmap.h>
+
+#include <dev/gpio/gpiobusvar.h>
+#include <dev/ofw/ofw_bus.h>
+
+#include <arm/broadcom/bcm2835/bcm2835_firmware.h>
+#include <arm/broadcom/bcm2835/bcm2835_vcbus.h>
+
+#include "gpio_if.h"
+
+#define RPI_VIRT_GPIO_PINS 2
+
+struct rpi_virt_gpio_softc {
+ device_t busdev;
+ device_t firmware;
+ struct mtx sc_mtx;
+
+ void *vaddr; /* Virtual address. */
+ vm_paddr_t paddr; /* Physical address. */
+
+ struct gpio_pin gpio_pins[RPI_VIRT_GPIO_PINS];
+ uint32_t state[RPI_VIRT_GPIO_PINS];
+};
+
+#define RPI_VIRT_GPIO_LOCK(_sc) mtx_lock(&(_sc)->sc_mtx)
+#define RPI_VIRT_GPIO_UNLOCK(_sc) mtx_unlock(&(_sc)->sc_mtx)
+
+static struct ofw_compat_data compat_data[] = {
+ {"brcm,bcm2835-virtgpio", 1},
+ {NULL, 0}
+};
+
+static device_t
+rpi_virt_gpio_get_bus(device_t dev)
+{
+ struct rpi_virt_gpio_softc *sc;
+
+ sc = device_get_softc(dev);
+
+ return (sc->busdev);
+}
+
+static int
+rpi_virt_gpio_pin_max(device_t dev, int *maxpin)
+{
+ *maxpin = RPI_VIRT_GPIO_PINS - 1;
+
+ return (0);
+}
+
+static int
+rpi_virt_gpio_pin_getcaps(device_t dev, uint32_t pin, uint32_t *caps)
+{
+ if (pin >= RPI_VIRT_GPIO_PINS)
+ return (EINVAL);
+
+ *caps = GPIO_PIN_OUTPUT;
+
+ return (0);
+}
+
+static int
+rpi_virt_gpio_pin_getflags(device_t dev, uint32_t pin, uint32_t *flags)
+{
+ if (pin >= RPI_VIRT_GPIO_PINS)
+ return (EINVAL);
+
+ *flags = GPIO_PIN_OUTPUT;
+
+ return (0);
+}
+
+static int
+rpi_virt_gpio_pin_set(device_t dev, uint32_t pin, uint32_t value)
+{
+ struct rpi_virt_gpio_softc *sc;
+ uint32_t *ptr;
+ uint16_t on, off;
+
+ if (pin >= RPI_VIRT_GPIO_PINS)
+ return (EINVAL);
+
+ sc = device_get_softc(dev);
+
+ RPI_VIRT_GPIO_LOCK(sc);
+ on = (uint16_t)(sc->state[pin] >> 16);
+ off = (uint16_t)sc->state[pin];
+
+ if (bootverbose)
+ device_printf(dev, "on: %hu, off: %hu, now: %d -> %u\n",
+ on, off, on - off, value);
+
+ if ((value > 0 && on - off != 0) || (value == 0 && on - off == 0)) {
+ RPI_VIRT_GPIO_UNLOCK(sc);
+ return (0);
+ }
+
+ if (value > 0)
+ ++on;
+ else
+ ++off;
+
+ sc->state[pin] = (on << 16 | off);
+ ptr = (uint32_t *)sc->vaddr;
+ ptr[pin] = sc->state[pin];
+ RPI_VIRT_GPIO_UNLOCK(sc);
+
+ return (0);
+}
+
+static int
+rpi_virt_gpio_pin_get(device_t dev, uint32_t pin, uint32_t *val)
+{
+ struct rpi_virt_gpio_softc *sc;
+ uint32_t *ptr, v;
+
+ if (pin >= RPI_VIRT_GPIO_PINS)
+ return (EINVAL);
+
+ sc = device_get_softc(dev);
+
+ ptr = (uint32_t *)sc->vaddr;
+ RPI_VIRT_GPIO_LOCK(sc);
+ v = ptr[pin];
+ RPI_VIRT_GPIO_UNLOCK(sc);
+ *val = ((uint16_t)(v >> 16) - (uint16_t)v) == 0 ? 0 : 1;
+
+ return (0);
+}
+
+static int
+rpi_virt_gpio_pin_toggle(device_t dev, uint32_t pin)
+{
+ int rv;
+ unsigned int val;
+
+ if (pin >= RPI_VIRT_GPIO_PINS)
+ return (EINVAL);
+
+ rv = rpi_virt_gpio_pin_get(dev, pin, &val);
+ if (rv != 0)
+ return (rv);
+
+ rv = rpi_virt_gpio_pin_set(dev, pin, val == 0 ? 1 : 0);
+
+ return (rv);
+}
+
+static int
+rpi_virt_gpio_probe(device_t dev)
+{
+ device_t firmware;
+ phandle_t gpio;
+ union msg_gpiovirtbuf cfg;
+ int rv;
+
+ if (ofw_bus_status_okay(dev) == 0)
+ return (ENXIO);
+
+ if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
+ return (ENXIO);
+
+ gpio = ofw_bus_get_node(dev);
+ if (OF_hasprop(gpio, "gpio-controller") == 0)
+ return (ENXIO);
+
+ /* Check whether the firmware is ready. */
+ firmware = device_get_parent(dev);
+ rv = bcm2835_firmware_property(firmware,
+ BCM2835_FIRMWARE_TAG_GET_GPIOVIRTBUF, &cfg, sizeof(cfg));
+ if (rv != 0)
+ return (ENXIO);
+
+ device_set_desc(dev, "Raspberry Pi Virtual GPIO controller");
+
+ return (BUS_PROBE_DEFAULT);
+}
+
+static int
+rpi_virt_gpio_attach(device_t dev)
+{
+ struct rpi_virt_gpio_softc *sc;
+ union msg_gpiovirtbuf cfg;
+ int i, rv;
+
+ sc = device_get_softc(dev);
+ sc->firmware = device_get_parent(dev);
+ mtx_init(&sc->sc_mtx, "Raspberry Pi virtgpio", NULL, MTX_SPIN);
+
+ /*
+ * According to the Linux source at:
+ * https://github.com/raspberrypi/linux/blob/rpi-6.12.y/drivers/gpio/gpio-bcm-virt.c
+ * it first attempts to set the pre-allocated physical memory address
+ * in the firmware. If it is successfully acquired, access virtgpio via
+ * the virtual memory address mapped to that physical address.
+ *
+ * If the above fails, then as a fallback, attempts to obtain a
+ * physical memory address for accessing virtgpio from the firmware.
+ * And if obtained, link it to a virtual memory address and access
+ * virtgpio via it.
+ *
+ * An OpenWRT virtgpio driver I happened to see at first only
+ * implemented the fallback method. Then I implemented this method on
+ * FreeBSD and tested it with the 20240429 firmware, but it didn't
+ * work.
+ *
+ * At this point, I realised the first method in the source above. So I
+ * implemented this method on FreeBSD and tested it, and it worked. In
+ * my opinion, the second method was used until some time prior to
+ * 20240429, and then the firmware was modified and the first method
+ * was introduced. In my driver, only the first method exists.
+ */
+
+ /* Allocate a physical memory range for accessing virtgpio. */
+ sc->vaddr = contigmalloc(
+ PAGE_SIZE, /* size */
+ M_DEVBUF, M_ZERO, /* type, flags */
+ 0, BCM2838_PERIPH_MAXADDR, /* low, high */
+ PAGE_SIZE, 0); /* alignment, boundary */
+ if (sc->vaddr == NULL) {
+ device_printf(dev, "Failed to allocate memory.\n");
+ return ENOMEM;
+ }
+ sc->paddr = vtophys(sc->vaddr);
+ /* Mark it uncacheable. */
+ pmap_change_attr((vm_offset_t)sc->vaddr, PAGE_SIZE,
+ VM_MEMATTR_UNCACHEABLE);
+
+ if (bootverbose)
+ device_printf(dev,
+ "KVA alloc'd: virtual: %p, phys: %#jx\n",
+ sc->vaddr, (uintmax_t)sc->paddr);
+
+ /* Set this address in firmware. */
+ cfg.req.addr = (uint32_t)sc->paddr;
+ rv = bcm2835_firmware_property(sc->firmware,
+ BCM2835_FIRMWARE_TAG_SET_GPIOVIRTBUF, &cfg, sizeof(cfg));
+ if (bootverbose)
+ device_printf(dev, "rv: %d, addr: 0x%x\n", rv, cfg.resp.addr);
+ if (rv != 0 || cfg.resp.addr != 0)
+ goto fail;
+
+ /* Pins only support output. */
+ for (i = 0; i < RPI_VIRT_GPIO_PINS; i++) {
+ sc->gpio_pins[i].gp_pin = i;
+ sc->gpio_pins[i].gp_caps = sc->gpio_pins[i].gp_flags
+ = GPIO_PIN_OUTPUT;
+ }
+ sc->busdev = gpiobus_attach_bus(dev);
+ if (sc->busdev == NULL)
+ goto fail;
+
+ return (0);
+
+fail:
+ /* Release resource if necessary. */
+ free(sc->vaddr, M_DEVBUF);
+ mtx_destroy(&sc->sc_mtx);
+
+ return (ENXIO);
+}
+
+static int
+rpi_virt_gpio_detach(device_t dev)
+{
+ return (EBUSY);
+}
+
+static device_method_t rpi_virt_gpio_methods[] = {
+ /* Device interface */
+ DEVMETHOD(device_probe, rpi_virt_gpio_probe),
+ DEVMETHOD(device_attach, rpi_virt_gpio_attach),
+ DEVMETHOD(device_detach, rpi_virt_gpio_detach),
+
+ /* GPIO protocol */
+ DEVMETHOD(gpio_get_bus, rpi_virt_gpio_get_bus),
+ DEVMETHOD(gpio_pin_max, rpi_virt_gpio_pin_max),
+ DEVMETHOD(gpio_pin_getcaps, rpi_virt_gpio_pin_getcaps),
+ DEVMETHOD(gpio_pin_getflags, rpi_virt_gpio_pin_getflags),
+ DEVMETHOD(gpio_pin_set, rpi_virt_gpio_pin_set),
+ DEVMETHOD(gpio_pin_get, rpi_virt_gpio_pin_get),
+ DEVMETHOD(gpio_pin_toggle, rpi_virt_gpio_pin_toggle),
+
+ DEVMETHOD_END
+};
+
+static driver_t rpi_virt_gpio_driver = {
+ "gpio",
+ rpi_virt_gpio_methods,
+ sizeof(struct rpi_virt_gpio_softc),
+};
+
+EARLY_DRIVER_MODULE(rpi_virt_gpio, bcm2835_firmware, rpi_virt_gpio_driver,
+ 0, 0, BUS_PASS_INTERRUPT + BUS_PASS_ORDER_LATE);
diff --git a/sys/conf/files.arm64 b/sys/conf/files.arm64
--- a/sys/conf/files.arm64
+++ b/sys/conf/files.arm64
@@ -580,6 +580,7 @@
arm/broadcom/bcm2835/bcm2838_pci.c optional soc_brcm_bcm2838 fdt pci
arm/broadcom/bcm2835/bcm2838_xhci.c optional soc_brcm_bcm2838 fdt pci xhci
arm/broadcom/bcm2835/raspberrypi_gpio.c optional soc_brcm_bcm2837 gpio fdt | soc_brcm_bcm2838 gpio fdt
+arm/broadcom/bcm2835/raspberrypi_virtgpio.c optional soc_brcm_bcm2837 gpio fdt | soc_brcm_bcm2838 gpio fdt
contrib/vchiq/interface/compat/vchi_bsd.c optional vchiq soc_brcm_bcm2837 \
compile-with "${NORMAL_C} -DUSE_VCHIQ_ARM -D__VCCOREVER__=0x04000000 -I$S/contrib/vchiq"
contrib/vchiq/interface/vchiq_arm/vchiq_2835_arm.c optional vchiq soc_brcm_bcm2837 \

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