Add syscon power and reset control device driver
This device driver supports both syscon-power and syscon-reset devices, as specified in [1] and [2]. These provide a very simple interface for power and reset control, and among other things are used by QEMU's virt machine on RISC-V. A separate commit will enable this on RISC-V, as that requires adding a RISC-V-specific riscv_syscon akin to r327936's aw_syscon. [1] https://www.kernel.org/doc/Documentation/devicetree/bindings/power/reset/syscon-poweroff.txt [2] https://www.kernel.org/doc/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt Reviewed by: brooks (mentor), jhb (mentor) Approved by: brooks (mentor), jhb (mentor) Obtained from: CheriBSD Differential Revision: https://reviews.freebsd.org/D25724
This commit is contained in:
Jessica Clarke
parent
4f8212c8b2
commit
28da7c9ed0
@ -1702,6 +1702,7 @@ dev/extres/regulator/regulator_fixed.c optional ext_resources regulator fdt
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dev/extres/syscon/syscon.c optional ext_resources syscon
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dev/extres/syscon/syscon_generic.c optional ext_resources syscon fdt
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dev/extres/syscon/syscon_if.m optional ext_resources syscon
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dev/extres/syscon/syscon_power.c optional ext_resources syscon syscon_power fdt
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dev/fb/fbd.c optional fbd | vt
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dev/fb/fb_if.m standard
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dev/fb/splash.c optional sc splash
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198
sys/dev/extres/syscon/syscon_power.c
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198
sys/dev/extres/syscon/syscon_power.c
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@ -0,0 +1,198 @@
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/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2020 Jessica Clarke <jrtc27@FreeBSD.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* Driver for simple syscon poweroff and reset devices. The device tree
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* specifications are fully described at:
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*
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* https://www.kernel.org/doc/Documentation/devicetree/bindings/power/reset/syscon-poweroff.txt
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* https://www.kernel.org/doc/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/bus.h>
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#include <sys/types.h>
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#include <sys/eventhandler.h>
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#include <sys/kernel.h>
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#include <sys/module.h>
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#include <sys/reboot.h>
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#include <machine/bus.h>
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#include <dev/ofw/ofw_bus.h>
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#include <dev/ofw/ofw_bus_subr.h>
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#include <dev/ofw/openfirm.h>
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#include "syscon_if.h"
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#include "syscon.h"
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struct syscon_power_softc {
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struct syscon *regmap;
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uint32_t offset;
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uint32_t value;
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uint32_t mask;
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bool reboot;
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eventhandler_tag shutdown_tag;
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};
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static void
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syscon_power_shutdown_final(device_t dev, int howto)
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{
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struct syscon_power_softc *sc;
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bool write;
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sc = device_get_softc(dev);
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if (sc->reboot)
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write = (howto & RB_HALT) == 0;
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else
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write = (howto & RB_POWEROFF) != 0;
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if (write)
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SYSCON_MODIFY_4(sc->regmap, sc->offset, sc->mask,
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sc->value & sc->mask);
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}
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static int
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syscon_power_probe(device_t dev)
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{
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if (!ofw_bus_status_okay(dev))
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return (ENXIO);
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if (ofw_bus_is_compatible(dev, "syscon-poweroff")) {
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device_set_desc(dev, "Syscon poweroff");
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return (BUS_PROBE_DEFAULT);
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} else if (ofw_bus_is_compatible(dev, "syscon-reboot")) {
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device_set_desc(dev, "Syscon reboot");
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return (BUS_PROBE_DEFAULT);
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}
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return (ENXIO);
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}
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static int
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syscon_power_attach(device_t dev)
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{
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struct syscon_power_softc *sc;
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phandle_t node;
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int error, len;
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bool has_mask;
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sc = device_get_softc(dev);
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node = ofw_bus_get_node(dev);
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if (!OF_hasprop(node, "regmap")) {
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device_printf(dev, "could not find regmap\n");
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return (ENXIO);
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}
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error = syscon_get_by_ofw_property(dev, node, "regmap", &sc->regmap);
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if (error != 0) {
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device_printf(dev, "could not get syscon\n");
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return (ENXIO);
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}
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len = OF_getproplen(node, "offset");
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if (len != 4) {
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device_printf(dev, "could not get offset\n");
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return (ENXIO);
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}
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OF_getencprop(node, "offset", &sc->offset, sizeof(sc->offset));
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/* Optional mask */
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has_mask = OF_hasprop(node, "mask");
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if (has_mask) {
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len = OF_getproplen(node, "mask");
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if (len != 4) {
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device_printf(dev, "cannot handle mask\n");
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return (ENXIO);
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}
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OF_getencprop(node, "mask", &sc->mask, sizeof(sc->mask));
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} else {
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sc->mask = 0xffffffff;
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}
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/*
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* From the device tree specification:
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*
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* Legacy usage: If a node doesn't contain a value property but
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* contains a mask property, the mask property is used as the value.
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*/
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if (!OF_hasprop(node, "value")) {
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if (!has_mask) {
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device_printf(dev, "must have a value or a mask\n");
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return (ENXIO);
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}
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sc->value = sc->mask;
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} else {
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len = OF_getproplen(node, "value");
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if (len != 4) {
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device_printf(dev, "cannot handle value\n");
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return (ENXIO);
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}
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OF_getencprop(node, "value", &sc->value, sizeof(sc->value));
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}
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sc->reboot = ofw_bus_is_compatible(dev, "syscon-reboot");
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sc->shutdown_tag = EVENTHANDLER_REGISTER(shutdown_final,
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syscon_power_shutdown_final, dev, SHUTDOWN_PRI_LAST);
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return (0);
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}
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static int
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syscon_power_detach(device_t dev)
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{
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struct syscon_power_softc *sc;
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sc = device_get_softc(dev);
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EVENTHANDLER_DEREGISTER(shutdown_final, sc->shutdown_tag);
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return (0);
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}
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static device_method_t syscon_power_methods[] = {
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DEVMETHOD(device_probe, syscon_power_probe),
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DEVMETHOD(device_attach, syscon_power_attach),
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DEVMETHOD(device_detach, syscon_power_detach),
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DEVMETHOD_END
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};
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DEFINE_CLASS_0(syscon_power, syscon_power_driver, syscon_power_methods,
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sizeof(struct syscon_power_softc));
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static devclass_t syscon_power_devclass;
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DRIVER_MODULE(syscon_power, simplebus, syscon_power_driver,
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syscon_power_devclass, NULL, NULL);
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