398 lines
11 KiB
C
398 lines
11 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2019 Ian Lepore <ian@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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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_platform.h"
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#include <sys/param.h>
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#include <sys/bus.h>
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#include <sys/kernel.h>
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#include <sys/module.h>
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#include <sys/sysctl.h>
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#ifdef FDT
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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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#endif
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#include <dev/iicbus/iiconf.h>
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#include "iicbus_if.h"
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#include "iicmux_if.h"
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#include "iicmux.h"
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/*------------------------------------------------------------------------------
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* iicbus methods, called by the iicbus functions in iiconf.c.
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*
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* All these functions return an IIC adapter-layer error code (because we are
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* pretending to be a host bridge/i2c controller). Standard errno values
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* returned from these must be encoded using iic2errno().
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*----------------------------------------------------------------------------*/
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static int
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iicmux_callback(device_t dev, int index, caddr_t data)
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{
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struct iicmux_softc *sc = device_get_softc(dev);
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struct iic_reqbus_data *rd;
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int err, i;
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/* If it's not one of the operations we know about, bail early. */
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if (index != IIC_REQUEST_BUS && index != IIC_RELEASE_BUS)
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return (iic2errno(EOPNOTSUPP));
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/*
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* Ensure that the data passed to us includes the device_t of the child
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* bus and device. If missing, someone bypassed iicbus_request_bus()
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* and called this method directly using the old calling standard. If
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* present, find the index of the child bus that called us.
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*/
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rd = (struct iic_reqbus_data *)data;
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if (!(rd->flags & IIC_REQBUS_DEV))
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return (iic2errno(EINVAL));
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for (i = 0; i <= sc->maxbus && sc->childdevs[i] != rd->bus; ++i)
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continue;
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if (i > sc->maxbus)
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return (iic2errno(ENOENT));
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/*
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* If the operation is a release it "cannot fail". Idle the downstream
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* bus, then release exclusive use of the upstream bus, and we're done.
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*/
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if (index == IIC_RELEASE_BUS) {
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if (sc->debugmux > 0) {
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device_printf(dev, "idle the bus for %s on bus %s\n",
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device_get_nameunit(rd->dev),
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device_get_nameunit(rd->bus));
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}
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IICMUX_BUS_SELECT(dev, IICMUX_SELECT_IDLE, rd);
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iicbus_release_bus(sc->busdev, dev);
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return (IIC_NOERR);
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}
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if (sc->debugmux > 0) {
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device_printf(dev, "select bus idx %d for %s on bus %s\n", i,
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device_get_nameunit(rd->dev), device_get_nameunit(rd->bus));
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}
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/*
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* The operation is a request for exclusive use. First we have to
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* request exclusive use of our upstream bus. If multiple slave devices
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* from our different child buses attempt to do IO at the same time,
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* this is what ensures that they don't switch the bus out from under
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* each other. The first one in proceeds and others wait here (or get an
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* EWOULDBLOCK return if they're using IIC_DONTWAIT).
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*/
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if ((err = iicbus_request_bus(sc->busdev, dev, rd->flags)) != 0)
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return (err); /* Already an IIC error code. */
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/*
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* Now that we own exclusive use of the upstream bus, connect it to the
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* downstream bus where the request came from.
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*/
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if ((err = IICMUX_BUS_SELECT(dev, i, rd)) != 0)
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iicbus_release_bus(sc->busdev, dev);
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return (err);
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}
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static u_int
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iicmux_get_frequency(device_t dev, u_char speed)
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{
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struct iicmux_softc *sc = device_get_softc(dev);
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return (IICBUS_GET_FREQUENCY(sc->busdev, speed));
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}
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#ifdef FDT
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static phandle_t
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iicmux_get_node(device_t dev, device_t child)
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{
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struct iicmux_softc *sc = device_get_softc(dev);
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int i;
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for (i = 0; i <= sc->maxbus; ++i) {
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if (sc->childdevs[i] == child)
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return (sc->childnodes[i]);
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}
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return (0); /* null handle */
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}
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#endif
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static int
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iicmux_intr(device_t dev, int event, char *buf)
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{
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struct iicmux_softc *sc = device_get_softc(dev);
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/* XXX iicbus_intr() in iiconf.c should return status. */
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iicbus_intr(sc->busdev, event, buf);
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return (0);
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}
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static int
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iicmux_read(device_t dev, char *buf, int len, int *bytes, int last, int delay)
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{
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struct iicmux_softc *sc = device_get_softc(dev);
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return (iicbus_read(sc->busdev, buf, len, bytes, last, delay));
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}
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static int
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iicmux_repeated_start(device_t dev, u_char slave, int timeout)
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{
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struct iicmux_softc *sc = device_get_softc(dev);
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return (iicbus_repeated_start(sc->busdev, slave, timeout));
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}
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static int
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iicmux_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
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{
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struct iicmux_softc *sc = device_get_softc(dev);
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return (iicbus_reset(sc->busdev, speed, addr, oldaddr));
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}
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static int
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iicmux_start(device_t dev, u_char slave, int timeout)
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{
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struct iicmux_softc *sc = device_get_softc(dev);
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return (iicbus_start(sc->busdev, slave, timeout));
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}
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static int
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iicmux_stop(device_t dev)
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{
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struct iicmux_softc *sc = device_get_softc(dev);
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return (iicbus_stop(sc->busdev));
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}
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static int
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iicmux_transfer( device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
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{
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struct iicmux_softc *sc = device_get_softc(dev);
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return (iicbus_transfer(sc->busdev, msgs, nmsgs));
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}
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static int
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iicmux_write(device_t dev, const char *buf, int len, int *bytes, int timeout)
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{
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struct iicmux_softc *sc = device_get_softc(dev);
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return (iicbus_write(sc->busdev, buf, len, bytes, timeout));
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}
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/*------------------------------------------------------------------------------
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* iicmux helper functions, called by hardware-specific drivers.
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* All these functions return a standard errno value.
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*----------------------------------------------------------------------------*/
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int
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iicmux_add_child(device_t dev, device_t child, int busidx)
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{
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struct iicmux_softc *sc = device_get_softc(dev);
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if (busidx >= sc->numbuses) {
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device_printf(dev,
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"iicmux_add_child: bus idx %d too big", busidx);
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return (EINVAL);
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}
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if (sc->childdevs[busidx] != NULL) {
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device_printf(dev, "iicmux_add_child: bus idx %d already added",
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busidx);
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return (EINVAL);
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}
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sc->childdevs[busidx] = child;
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if (sc->maxbus < busidx)
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sc->maxbus = busidx;
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return (0);
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}
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static int
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iicmux_attach_children(struct iicmux_softc *sc)
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{
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int i;
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#ifdef FDT
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phandle_t child, node, parent;
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pcell_t idx;
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/*
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* Find our FDT node. Child nodes within our node will become our
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* iicbus children.
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*/
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if((node = ofw_bus_get_node(sc->dev)) == 0) {
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device_printf(sc->dev, "cannot find FDT node\n");
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return (ENOENT);
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}
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/*
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* First we have to see if there is a child node named "i2c-mux". If it
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* exists, all children of that node are buses, else all children of the
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* device node are buses.
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*/
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if ((parent = ofw_bus_find_child(node, "i2c-mux")) == 0)
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parent = node;
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/*
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* Attach the children represented in the device tree.
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*/
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for (child = OF_child(parent); child != 0; child = OF_peer(child)) {
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if (OF_getencprop(child, "reg", &idx, sizeof(idx)) == -1) {
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device_printf(sc->dev,
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"child bus missing required 'reg' property\n");
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continue;
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}
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if (idx >= sc->numbuses) {
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device_printf(sc->dev,
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"child bus 'reg' property %d exceeds the number "
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"of buses supported by the device (%d)\n",
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idx, sc->numbuses);
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continue;
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}
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sc->childdevs[idx] = device_add_child(sc->dev, "iicbus", -1);
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sc->childnodes[idx] = child;
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if (sc->maxbus < idx)
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sc->maxbus = idx;
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}
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/* If we configured anything using FDT data, we're done. */
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if (sc->maxbus >= 0)
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return (0);
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#endif /* FDT */
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/*
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* If we make it to here, we didn't add any children based on FDT data.
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* Add an iicbus child for every downstream bus supported by the mux.
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*/
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for (i = 0; i < sc->numbuses; ++i) {
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sc->childdevs[i] = device_add_child(sc->dev, "iicbus", -1);
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sc->maxbus = i;
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}
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return (0);
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}
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int
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iicmux_attach(device_t dev, device_t busdev, int numbuses)
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{
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struct iicmux_softc *sc = device_get_softc(dev);
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int err;
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if (numbuses >= IICMUX_MAX_BUSES) {
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device_printf(dev, "iicmux_attach: numbuses %d > max %d\n",
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numbuses, IICMUX_MAX_BUSES);
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return (EINVAL);
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}
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sc->dev = dev;
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sc->busdev = busdev;
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sc->maxbus = -1;
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sc->numbuses = numbuses;
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if ((err = iicmux_attach_children(sc)) != 0)
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return (err);
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SYSCTL_ADD_UINT(device_get_sysctl_ctx(sc->dev),
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SYSCTL_CHILDREN(device_get_sysctl_tree(sc->dev)), OID_AUTO,
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"debugmux", CTLFLAG_RWTUN, &sc->debugmux, 0, "debug mux operations");
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return (0);
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}
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int
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iicmux_detach(device_t dev)
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{
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struct iicmux_softc *sc = device_get_softc(dev);
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int err, i;
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/* Delete only the children we added in iicmux_add* functions. */
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for (i = 0; i <= sc->maxbus; ++i) {
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if (sc->childdevs[i] == NULL)
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continue;
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if ((err = device_delete_child(dev, sc->childdevs[i])) != 0)
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return (err);
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sc->childdevs[i] = NULL;
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}
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return (0);
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}
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static device_method_t iicmux_methods [] = {
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/* iicbus_if methods */
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DEVMETHOD(iicbus_intr, iicmux_intr),
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DEVMETHOD(iicbus_callback, iicmux_callback),
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DEVMETHOD(iicbus_repeated_start, iicmux_repeated_start),
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DEVMETHOD(iicbus_start, iicmux_start),
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DEVMETHOD(iicbus_stop, iicmux_stop),
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DEVMETHOD(iicbus_read, iicmux_read),
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DEVMETHOD(iicbus_write, iicmux_write),
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DEVMETHOD(iicbus_reset, iicmux_reset),
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DEVMETHOD(iicbus_transfer, iicmux_transfer),
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DEVMETHOD(iicbus_get_frequency, iicmux_get_frequency),
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#ifdef FDT
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/* ofwbus_if methods */
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DEVMETHOD(ofw_bus_get_node, iicmux_get_node),
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#endif
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DEVMETHOD_END
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};
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static int
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iicmux_modevent(module_t mod, int type, void *unused)
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{
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switch (type) {
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case MOD_LOAD:
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return 0;
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case MOD_UNLOAD:
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return 0;
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}
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return EINVAL;
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}
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static moduledata_t iicmux_mod = {
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"iicmux",
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iicmux_modevent,
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0
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};
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DEFINE_CLASS_0(iicmux, iicmux_driver, iicmux_methods,
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sizeof(struct iicmux_softc));
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DECLARE_MODULE(iicmux, iicmux_mod, SI_SUB_DRIVERS, SI_ORDER_ANY);
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MODULE_VERSION(iicmux, 1);
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MODULE_DEPEND(iicmux, iicbus, 1, 1, 1);
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