/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2024 Ahmad Khalifa <ahmadkhalifa570@gmail.com>
 *
 * 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 AUTHORS 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 AUTHORS 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/types.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/gpio.h>

#include <contrib/dev/acpica/include/acpi.h>
#include <dev/acpica/acpivar.h>

#include <dev/gpio/gpiobusvar.h>
#include <dev/gpio/acpi_gpiobusvar.h>

#include "gpiobus_if.h"

struct acpi_gpiobus_softc {
	struct gpiobus_softc	super_sc;
	ACPI_CONNECTION_INFO	handler_info;
};

struct acpi_gpiobus_ctx {
	struct gpiobus_softc	*sc;
	ACPI_HANDLE		dev_handle;
};

struct acpi_gpiobus_ivar
{
	struct gpiobus_ivar	gpiobus;	/* Must come first */
	ACPI_HANDLE		dev_handle;	/* ACPI handle for bus */
	uint32_t		flags;
};

static uint32_t
acpi_gpiobus_convflags(ACPI_RESOURCE_GPIO *gpio_res)
{
	uint32_t flags = 0;

	/* Figure out pin flags */
	if (gpio_res->ConnectionType == ACPI_RESOURCE_GPIO_TYPE_INT) {
		switch (gpio_res->Polarity) {
		case ACPI_ACTIVE_HIGH:
			flags = gpio_res->Triggering == ACPI_LEVEL_SENSITIVE ?
			    GPIO_INTR_LEVEL_HIGH : GPIO_INTR_EDGE_RISING;
			break;
		case ACPI_ACTIVE_LOW:
			flags = gpio_res->Triggering == ACPI_LEVEL_SENSITIVE ?
			    GPIO_INTR_LEVEL_LOW : GPIO_INTR_EDGE_FALLING;
			break;
		case ACPI_ACTIVE_BOTH:
			flags = GPIO_INTR_EDGE_BOTH;
			break;
		}

#ifdef NOT_YET
		/* This is not currently implemented. */
		if (gpio_res->Shareable == ACPI_SHARED)
			flags |= GPIO_INTR_SHAREABLE;
#endif
	}
	if (gpio_res->ConnectionType == ACPI_RESOURCE_GPIO_TYPE_IO) {
		switch (gpio_res->IoRestriction) {
		case ACPI_IO_RESTRICT_INPUT:
			flags |= GPIO_PIN_INPUT;
			break;
		case ACPI_IO_RESTRICT_OUTPUT:
			flags |= GPIO_PIN_OUTPUT;
			break;
		}
	}

	switch (gpio_res->PinConfig) {
	case ACPI_PIN_CONFIG_PULLUP:
		flags |= GPIO_PIN_PULLUP;
		break;
	case ACPI_PIN_CONFIG_PULLDOWN:
		flags |= GPIO_PIN_PULLDOWN;
		break;
	}

	return (flags);
}

static ACPI_STATUS
acpi_gpiobus_enumerate_res(ACPI_RESOURCE *res, void *context)
{
	ACPI_RESOURCE_GPIO *gpio_res = &res->Data.Gpio;
	struct acpi_gpiobus_ctx *ctx = context;
	struct gpiobus_softc *super_sc = ctx->sc;
	ACPI_HANDLE handle;
	uint32_t flags, i;

	if (res->Type != ACPI_RESOURCE_TYPE_GPIO)
		return (AE_OK);

	if (ACPI_FAILURE(AcpiGetHandle(ACPI_ROOT_OBJECT,
	    gpio_res->ResourceSource.StringPtr, &handle)) ||
	    handle != ctx->dev_handle)
		return (AE_OK);

	if (__predict_false(gpio_res->PinTableLength > super_sc->sc_npins)) {
		device_printf(super_sc->sc_busdev,
		    "invalid pin table length %hu, max: %d (bad ACPI tables?)\n",
		    gpio_res->PinTableLength, super_sc->sc_npins);
		return (AE_LIMIT);
	}

	flags = acpi_gpiobus_convflags(gpio_res);
	for (i = 0; i < gpio_res->PinTableLength; i++) {
		UINT16 pin = gpio_res->PinTable[i];

		if (__predict_false(pin >= super_sc->sc_npins)) {
			device_printf(super_sc->sc_busdev,
			    "invalid pin 0x%x, max: 0x%x (bad ACPI tables?)\n",
			    pin, super_sc->sc_npins - 1);
			return (AE_LIMIT);
		}

		GPIO_PIN_SETFLAGS(super_sc->sc_dev, pin, flags &
		    ~GPIO_INTR_MASK);
	}

	return (AE_OK);
}

static struct acpi_gpiobus_ivar *
acpi_gpiobus_setup_devinfo(device_t bus, device_t child,
    ACPI_RESOURCE_GPIO *gpio_res)
{
	struct acpi_gpiobus_ivar *devi;

	devi = malloc(sizeof(*devi), M_DEVBUF, M_NOWAIT | M_ZERO);
	if (devi == NULL)
		return (NULL);
	resource_list_init(&devi->gpiobus.rl);

	devi->flags = acpi_gpiobus_convflags(gpio_res);
	if (acpi_quirks & ACPI_Q_AEI_NOPULL)
		devi->flags &= ~GPIO_PIN_PULLUP;

	devi->gpiobus.npins = 1;
	if (gpiobus_alloc_ivars(&devi->gpiobus) != 0) {
		free(devi, M_DEVBUF);
		return (NULL);
	}

	for (int i = 0; i < devi->gpiobus.npins; i++)
		devi->gpiobus.pins[i] = gpio_res->PinTable[i];

	return (devi);
}

static ACPI_STATUS
acpi_gpiobus_enumerate_aei(ACPI_RESOURCE *res, void *context)
{
	ACPI_RESOURCE_GPIO *gpio_res = &res->Data.Gpio;
	struct acpi_gpiobus_ctx *ctx = context;
	device_t bus = ctx->sc->sc_busdev;
	device_t child;
	struct acpi_gpiobus_ivar *devi;

	/* Check that we have a GpioInt object. */
	if (res->Type != ACPI_RESOURCE_TYPE_GPIO)
		return (AE_OK);
	if (gpio_res->ConnectionType != ACPI_RESOURCE_GPIO_TYPE_INT)
		return (AE_OK);

	/* Add a child. */
	child = device_add_child_ordered(bus, 0, "gpio_aei", DEVICE_UNIT_ANY);
	if (child == NULL)
		return (AE_OK);
	devi = acpi_gpiobus_setup_devinfo(bus, child, gpio_res);
	if (devi == NULL) {
		device_delete_child(bus, child);
		return (AE_OK);
	}
	device_set_ivars(child, devi);

	for (int i = 0; i < devi->gpiobus.npins; i++) {
		if (GPIOBUS_PIN_SETFLAGS(bus, child, 0, devi->flags)) {
			device_delete_child(bus, child);
			return (AE_OK);
		}
	}

	/* Pass ACPI information to children. */
	devi->dev_handle = ctx->dev_handle;

	return (AE_OK);
}

static ACPI_STATUS
acpi_gpiobus_enumerate(ACPI_HANDLE handle, UINT32 depth, void *context,
    void **result)
{
	UINT32 sta;

	/*
	 * If no _STA method or if it failed, then assume that
	 * the device is present.
	 */
	if (!ACPI_FAILURE(acpi_GetInteger(handle, "_STA", &sta)) &&
	    !ACPI_DEVICE_PRESENT(sta))
		return (AE_OK);

	if (!acpi_has_hid(handle))
		return (AE_OK);

	/* Look for GPIO resources */
	AcpiWalkResources(handle, "_CRS", acpi_gpiobus_enumerate_res, context);

	return (AE_OK);
}

static ACPI_STATUS
acpi_gpiobus_space_handler(UINT32 function, ACPI_PHYSICAL_ADDRESS address,
    UINT32 length, UINT64 *value, void *context, void *region_context)
{
	ACPI_CONNECTION_INFO *info = context;
	ACPI_RESOURCE_GPIO *gpio_res;
	device_t controller;
	ACPI_RESOURCE *res;
	ACPI_STATUS status;

	status = AcpiBufferToResource(info->Connection, info->Length, &res);
	if (ACPI_FAILURE(status) || res->Type != ACPI_RESOURCE_TYPE_GPIO)
		goto err;

	gpio_res = &res->Data.Gpio;
	controller = __containerof(info, struct acpi_gpiobus_softc,
	    handler_info)->super_sc.sc_dev;

	switch (function) {
	case ACPI_WRITE:
		if (__predict_false(
		    gpio_res->IoRestriction == ACPI_IO_RESTRICT_INPUT))
			goto err;

		for (int i = 0; i < length; i++)
			if (GPIO_PIN_SET(controller,
			    gpio_res->PinTable[address + i], (*value & 1 << i) ?
			    GPIO_PIN_HIGH : GPIO_PIN_LOW) != 0)
				goto err;
		break;
	case ACPI_READ:
		if (__predict_false(
		    gpio_res->IoRestriction == ACPI_IO_RESTRICT_OUTPUT))
			goto err;

		for (int i = 0; i < length; i++) {
			uint32_t v;

			if (GPIO_PIN_GET(controller,
			    gpio_res->PinTable[address + i], &v) != 0)
				goto err;
			*value |= v << i;
		}
		break;
	default:
		goto err;
	}

	ACPI_FREE(res);
	return (AE_OK);

err:
	ACPI_FREE(res);
	return (AE_BAD_PARAMETER);
}

static int
acpi_gpiobus_probe(device_t dev)
{
	device_t controller;

	if (acpi_disabled("gpiobus"))
		return (ENXIO);

	controller = device_get_parent(dev);
	if (controller == NULL)
		return (ENXIO);

	if (acpi_get_handle(controller) == NULL)
		return (ENXIO);

	device_set_desc(dev, "GPIO bus (ACPI-hinted)");
	return (BUS_PROBE_DEFAULT);
}

static int
acpi_gpiobus_attach(device_t dev)
{
	struct acpi_gpiobus_softc *sc;
	struct acpi_gpiobus_ctx ctx;
	ACPI_HANDLE handle;
	ACPI_STATUS status;
	int err;

	if ((err = gpiobus_attach(dev)) != 0)
		return (err);

	sc = device_get_softc(dev);
	handle = acpi_get_handle(sc->super_sc.sc_dev);
	if (handle == NULL) {
		gpiobus_detach(dev);
		return (ENXIO);
	}

	status = AcpiInstallAddressSpaceHandler(handle, ACPI_ADR_SPACE_GPIO,
	    acpi_gpiobus_space_handler, NULL, &sc->handler_info);

	if (ACPI_FAILURE(status)) {
		device_printf(dev,
		    "Failed to install GPIO address space handler\n");
		gpiobus_detach(dev);
		return (ENXIO);
	}

	ctx.dev_handle = handle;
	ctx.sc = &sc->super_sc;

	status = AcpiWalkNamespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
	    ACPI_UINT32_MAX, acpi_gpiobus_enumerate, NULL, &ctx, NULL);

	if (ACPI_FAILURE(status))
		device_printf(dev, "Failed to enumerate GPIO resources\n");

	/* Look for AEI children */
	status = AcpiWalkResources(handle, "_AEI", acpi_gpiobus_enumerate_aei,
	    &ctx);

	if (ACPI_FAILURE(status))
		device_printf(dev, "Failed to enumerate GPIO resources\n");

	return (0);
}

static int
acpi_gpiobus_detach(device_t dev)
{
	struct gpiobus_softc *super_sc;
	ACPI_STATUS status;

	super_sc = device_get_softc(dev);
	status = AcpiRemoveAddressSpaceHandler(
	    acpi_get_handle(super_sc->sc_dev), ACPI_ADR_SPACE_GPIO,
	    acpi_gpiobus_space_handler
	);

	if (ACPI_FAILURE(status))
		device_printf(dev,
		    "Failed to remove GPIO address space handler\n");

	return (gpiobus_detach(dev));
}

int
gpio_pin_get_by_acpi_index(device_t consumer, uint32_t idx,
    gpio_pin_t *out_pin)
{
	struct acpi_gpiobus_ivar *devi;
	int rv;

	rv = gpio_pin_get_by_child_index(consumer, idx, out_pin);
	if (rv != 0)
		return (rv);

	devi = device_get_ivars(consumer);
	(*out_pin)->flags = devi->flags;

	return (0);
}

static int
acpi_gpiobus_read_ivar(device_t dev, device_t child, int which, uintptr_t *result)
{
	struct acpi_gpiobus_ivar *devi = device_get_ivars(child);

	switch (which) {
	case ACPI_GPIOBUS_IVAR_HANDLE:
		*result = (uintptr_t)devi->dev_handle;
		break;
	default:
		return (gpiobus_read_ivar(dev, child, which, result));
	}

	return (0);
}

static device_method_t acpi_gpiobus_methods[] = {
	/* Device interface */
	DEVMETHOD(device_probe,		acpi_gpiobus_probe),
	DEVMETHOD(device_attach,	acpi_gpiobus_attach),
	DEVMETHOD(device_detach,	acpi_gpiobus_detach),

	/* Bus interface */
	DEVMETHOD(bus_read_ivar,	acpi_gpiobus_read_ivar),

	DEVMETHOD_END
};

DEFINE_CLASS_1(gpiobus, acpi_gpiobus_driver, acpi_gpiobus_methods,
    sizeof(struct acpi_gpiobus_softc), gpiobus_driver);
EARLY_DRIVER_MODULE(acpi_gpiobus, gpio, acpi_gpiobus_driver, NULL, NULL,
    BUS_PASS_BUS + BUS_PASS_ORDER_MIDDLE);
MODULE_VERSION(acpi_gpiobus, 1);
MODULE_DEPEND(acpi_gpiobus, acpi, 1, 1, 1);