/*
 *  Copyright (c) 2013 Andrew Duggan <aduggan@synaptics.com>
 *  Copyright (c) 2013 Synaptics Incorporated
 *  Copyright (c) 2014 Benjamin Tissoires <benjamin.tissoires@gmail.com>
 *  Copyright (c) 2014 Red Hat, Inc
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 */

#include <linux/kernel.h>
#include <linux/hid.h>
#include <linux/input.h>
#include <linux/input/mt.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/pm.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/rmi.h>
#include "hid-ids.h"

#define RMI_MOUSE_REPORT_ID             0x01 /* Mouse emulation Report */
#define RMI_WRITE_REPORT_ID             0x09 /* Output Report */
#define RMI_READ_ADDR_REPORT_ID         0x0a /* Output Report */
#define RMI_READ_DATA_REPORT_ID         0x0b /* Input Report */
#define RMI_ATTN_REPORT_ID              0x0c /* Input Report */
#define RMI_SET_RMI_MODE_REPORT_ID      0x0f /* Feature Report */

/* flags */
#define RMI_READ_REQUEST_PENDING        0
#define RMI_READ_DATA_PENDING           1
#define RMI_STARTED                     2

/* device flags */
#define RMI_DEVICE                      BIT(0)
#define RMI_DEVICE_HAS_PHYS_BUTTONS     BIT(1)

/*
 * retrieve the ctrl registers
 * the ctrl register has a size of 20 but a fw bug split it into 16 + 4,
 * and there is no way to know if the first 20 bytes are here or not.
 * We use only the first 12 bytes, so get only them.
 */
#define RMI_F11_CTRL_REG_COUNT          12

enum rmi_mode_type {
        RMI_MODE_OFF                    = 0,
        RMI_MODE_ATTN_REPORTS           = 1,
        RMI_MODE_NO_PACKED_ATTN_REPORTS = 2,
};

/**
 * struct rmi_data - stores information for hid communication
 *
 * @page_mutex: Locks current page to avoid changing pages in unexpected ways.
 * @page: Keeps track of the current virtual page
 * @xport: transport device to be registered with the RMI4 core.
 *
 * @wait: Used for waiting for read data
 *
 * @writeReport: output buffer when writing RMI registers
 * @readReport: input buffer when reading RMI registers
 *
 * @input_report_size: size of an input report (advertised by HID)
 * @output_report_size: size of an output report (advertised by HID)
 *
 * @flags: flags for the current device (started, reading, etc...)
 *
 * @reset_work: worker which will be called in case of a mouse report
 * @hdev: pointer to the struct hid_device
 *
 * @device_flags: flags which describe the device
 *
 * @domain: the IRQ domain allocated for this RMI4 device
 * @rmi_irq: the irq that will be used to generate events to rmi-core
 */
struct rmi_data {
        struct mutex page_mutex;
        int page;
        struct rmi_transport_dev xport;

        wait_queue_head_t wait;

        u8 *writeReport;
        u8 *readReport;

        u32 input_report_size;
        u32 output_report_size;

        unsigned long flags;

        struct work_struct reset_work;
        struct hid_device *hdev;

        unsigned long device_flags;

        struct irq_domain *domain;
        int rmi_irq;
};

#define RMI_PAGE(addr) (((addr) >> 8) & 0xff)

static int rmi_write_report(struct hid_device *hdev, u8 *report, int len);

/**
 * rmi_set_page - Set RMI page
 * @hdev: The pointer to the hid_device struct
 * @page: The new page address.
 *
 * RMI devices have 16-bit addressing, but some of the physical
 * implementations (like SMBus) only have 8-bit addressing. So RMI implements
 * a page address at 0xff of every page so we can reliable page addresses
 * every 256 registers.
 *
 * The page_mutex lock must be held when this function is entered.
 *
 * Returns zero on success, non-zero on failure.
 */
static int rmi_set_page(struct hid_device *hdev, u8 page)
{
        struct rmi_data *data = hid_get_drvdata(hdev);
        int retval;

        data->writeReport[0] = RMI_WRITE_REPORT_ID;
        data->writeReport[1] = 1;
        data->writeReport[2] = 0xFF;
        data->writeReport[4] = page;

        retval = rmi_write_report(hdev, data->writeReport,
                        data->output_report_size);
        if (retval != data->output_report_size) {
                dev_err(&hdev->dev,
                        "%s: set page failed: %d.", __func__, retval);
                return retval;
        }

        data->page = page;
        return 0;
}

static int rmi_set_mode(struct hid_device *hdev, u8 mode)
{
        int ret;
        const u8 txbuf[2] = {RMI_SET_RMI_MODE_REPORT_ID, mode};
        u8 *buf;

        buf = kmemdup(txbuf, sizeof(txbuf), GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        ret = hid_hw_raw_request(hdev, RMI_SET_RMI_MODE_REPORT_ID, buf,
                        sizeof(txbuf), HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
        kfree(buf);
        if (ret < 0) {
                dev_err(&hdev->dev, "unable to set rmi mode to %d (%d)\n", mode,
                        ret);
                return ret;
        }

        return 0;
}

static int rmi_write_report(struct hid_device *hdev, u8 *report, int len)
{
        int ret;

        ret = hid_hw_output_report(hdev, (void *)report, len);
        if (ret < 0) {
                dev_err(&hdev->dev, "failed to write hid report (%d)\n", ret);
                return ret;
        }

        return ret;
}

static int rmi_hid_read_block(struct rmi_transport_dev *xport, u16 addr,
                void *buf, size_t len)
{
        struct rmi_data *data = container_of(xport, struct rmi_data, xport);
        struct hid_device *hdev = data->hdev;
        int ret;
        int bytes_read;
        int bytes_needed;
        int retries;
        int read_input_count;

        mutex_lock(&data->page_mutex);

        if (RMI_PAGE(addr) != data->page) {
                ret = rmi_set_page(hdev, RMI_PAGE(addr));
                if (ret < 0)
                        goto exit;
        }

        for (retries = 5; retries > 0; retries--) {
                data->writeReport[0] = RMI_READ_ADDR_REPORT_ID;
                data->writeReport[1] = 0; /* old 1 byte read count */
                data->writeReport[2] = addr & 0xFF;
                data->writeReport[3] = (addr >> 8) & 0xFF;
                data->writeReport[4] = len  & 0xFF;
                data->writeReport[5] = (len >> 8) & 0xFF;

                set_bit(RMI_READ_REQUEST_PENDING, &data->flags);

                ret = rmi_write_report(hdev, data->writeReport,
                                                data->output_report_size);
                if (ret != data->output_report_size) {
                        clear_bit(RMI_READ_REQUEST_PENDING, &data->flags);
                        dev_err(&hdev->dev,
                                "failed to write request output report (%d)\n",
                                ret);
                        goto exit;
                }

                bytes_read = 0;
                bytes_needed = len;
                while (bytes_read < len) {
                        if (!wait_event_timeout(data->wait,
                                test_bit(RMI_READ_DATA_PENDING, &data->flags),
                                        msecs_to_jiffies(1000))) {
                                hid_warn(hdev, "%s: timeout elapsed\n",
                                         __func__);
                                ret = -EAGAIN;
                                break;
                        }

                        read_input_count = data->readReport[1];
                        memcpy(buf + bytes_read, &data->readReport[2],
                                read_input_count < bytes_needed ?
                                        read_input_count : bytes_needed);

                        bytes_read += read_input_count;
                        bytes_needed -= read_input_count;
                        clear_bit(RMI_READ_DATA_PENDING, &data->flags);
                }

                if (ret >= 0) {
                        ret = 0;
                        break;
                }
        }

exit:
        clear_bit(RMI_READ_REQUEST_PENDING, &data->flags);
        mutex_unlock(&data->page_mutex);
        return ret;
}

static int rmi_hid_write_block(struct rmi_transport_dev *xport, u16 addr,
                const void *buf, size_t len)
{
        struct rmi_data *data = container_of(xport, struct rmi_data, xport);
        struct hid_device *hdev = data->hdev;
        int ret;

        mutex_lock(&data->page_mutex);

        if (RMI_PAGE(addr) != data->page) {
                ret = rmi_set_page(hdev, RMI_PAGE(addr));
                if (ret < 0)
                        goto exit;
        }

        data->writeReport[0] = RMI_WRITE_REPORT_ID;
        data->writeReport[1] = len;
        data->writeReport[2] = addr & 0xFF;
        data->writeReport[3] = (addr >> 8) & 0xFF;
        memcpy(&data->writeReport[4], buf, len);

        ret = rmi_write_report(hdev, data->writeReport,
                                        data->output_report_size);
        if (ret < 0) {
                dev_err(&hdev->dev,
                        "failed to write request output report (%d)\n",
                        ret);
                goto exit;
        }
        ret = 0;

exit:
        mutex_unlock(&data->page_mutex);
        return ret;
}

static int rmi_reset_attn_mode(struct hid_device *hdev)
{
        struct rmi_data *data = hid_get_drvdata(hdev);
        struct rmi_device *rmi_dev = data->xport.rmi_dev;
        int ret;

        ret = rmi_set_mode(hdev, RMI_MODE_ATTN_REPORTS);
        if (ret)
                return ret;

        if (test_bit(RMI_STARTED, &data->flags))
                ret = rmi_dev->driver->reset_handler(rmi_dev);

        return ret;
}

static void rmi_reset_work(struct work_struct *work)
{
        struct rmi_data *hdata = container_of(work, struct rmi_data,
                                                reset_work);

        /* switch the device to RMI if we receive a generic mouse report */
        rmi_reset_attn_mode(hdata->hdev);
}

static int rmi_input_event(struct hid_device *hdev, u8 *data, int size)
{
        struct rmi_data *hdata = hid_get_drvdata(hdev);
        struct rmi_device *rmi_dev = hdata->xport.rmi_dev;
        unsigned long flags;

        if (!(test_bit(RMI_STARTED, &hdata->flags)))
                return 0;

        local_irq_save(flags);

        rmi_set_attn_data(rmi_dev, data[1], &data[2], size - 2);

        generic_handle_irq(hdata->rmi_irq);

        local_irq_restore(flags);

        return 1;
}

static int rmi_read_data_event(struct hid_device *hdev, u8 *data, int size)
{
        struct rmi_data *hdata = hid_get_drvdata(hdev);

        if (!test_bit(RMI_READ_REQUEST_PENDING, &hdata->flags)) {
                hid_dbg(hdev, "no read request pending\n");
                return 0;
        }

        memcpy(hdata->readReport, data, size < hdata->input_report_size ?
                        size : hdata->input_report_size);
        set_bit(RMI_READ_DATA_PENDING, &hdata->flags);
        wake_up(&hdata->wait);

        return 1;
}

static int rmi_check_sanity(struct hid_device *hdev, u8 *data, int size)
{
        int valid_size = size;
        /*
         * On the Dell XPS 13 9333, the bus sometimes get confused and fills
         * the report with a sentinel value "ff". Synaptics told us that such
         * behavior does not comes from the touchpad itself, so we filter out
         * such reports here.
         */

        while ((data[valid_size - 1] == 0xff) && valid_size > 0)
                valid_size--;

        return valid_size;
}

static int rmi_raw_event(struct hid_device *hdev,
                struct hid_report *report, u8 *data, int size)
{
        struct rmi_data *hdata = hid_get_drvdata(hdev);

        if (!(hdata->device_flags & RMI_DEVICE))
                return 0;

        size = rmi_check_sanity(hdev, data, size);
        if (size < 2)
                return 0;

        switch (data[0]) {
        case RMI_READ_DATA_REPORT_ID:
                return rmi_read_data_event(hdev, data, size);
        case RMI_ATTN_REPORT_ID:
                return rmi_input_event(hdev, data, size);
        default:
                return 1;
        }

        return 0;
}

static int rmi_event(struct hid_device *hdev, struct hid_field *field,
                        struct hid_usage *usage, __s32 value)
{
        struct rmi_data *data = hid_get_drvdata(hdev);

        if ((data->device_flags & RMI_DEVICE) &&
            (field->application == HID_GD_POINTER ||
            field->application == HID_GD_MOUSE)) {
                if (data->device_flags & RMI_DEVICE_HAS_PHYS_BUTTONS) {
                        if ((usage->hid & HID_USAGE_PAGE) == HID_UP_BUTTON)
                                return 0;

                        if ((usage->hid == HID_GD_X || usage->hid == HID_GD_Y)
                            && !value)
                                return 1;
                }

                schedule_work(&data->reset_work);
                return 1;
        }

        return 0;
}

#ifdef CONFIG_PM
static int rmi_suspend(struct hid_device *hdev, pm_message_t message)
{
        struct rmi_data *data = hid_get_drvdata(hdev);
        struct rmi_device *rmi_dev = data->xport.rmi_dev;
        int ret;

        if (!(data->device_flags & RMI_DEVICE))
                return 0;

        ret = rmi_driver_suspend(rmi_dev, false);
        if (ret) {
                hid_warn(hdev, "Failed to suspend device: %d\n", ret);
                return ret;
        }

        return 0;
}

static int rmi_post_resume(struct hid_device *hdev)
{
        struct rmi_data *data = hid_get_drvdata(hdev);
        struct rmi_device *rmi_dev = data->xport.rmi_dev;
        int ret;

        if (!(data->device_flags & RMI_DEVICE))
                return 0;

        /* Make sure the HID device is ready to receive events */
        ret = hid_hw_open(hdev);
        if (ret)
                return ret;

        ret = rmi_reset_attn_mode(hdev);
        if (ret)
                goto out;

        ret = rmi_driver_resume(rmi_dev, false);
        if (ret) {
                hid_warn(hdev, "Failed to resume device: %d\n", ret);
                goto out;
        }

out:
        hid_hw_close(hdev);
        return ret;
}
#endif /* CONFIG_PM */

static int rmi_hid_reset(struct rmi_transport_dev *xport, u16 reset_addr)
{
        struct rmi_data *data = container_of(xport, struct rmi_data, xport);
        struct hid_device *hdev = data->hdev;

        return rmi_reset_attn_mode(hdev);
}

static int rmi_input_configured(struct hid_device *hdev, struct hid_input *hi)
{
        struct rmi_data *data = hid_get_drvdata(hdev);
        struct input_dev *input = hi->input;
        int ret = 0;

        if (!(data->device_flags & RMI_DEVICE))
                return 0;

        data->xport.input = input;

        hid_dbg(hdev, "Opening low level driver\n");
        ret = hid_hw_open(hdev);
        if (ret)
                return ret;

        /* Allow incoming hid reports */
        hid_device_io_start(hdev);

        ret = rmi_set_mode(hdev, RMI_MODE_ATTN_REPORTS);
        if (ret < 0) {
                dev_err(&hdev->dev, "failed to set rmi mode\n");
                goto exit;
        }

        ret = rmi_set_page(hdev, 0);
        if (ret < 0) {
                dev_err(&hdev->dev, "failed to set page select to 0.\n");
                goto exit;
        }

        ret = rmi_register_transport_device(&data->xport);
        if (ret < 0) {
                dev_err(&hdev->dev, "failed to register transport driver\n");
                goto exit;
        }

        set_bit(RMI_STARTED, &data->flags);

exit:
        hid_device_io_stop(hdev);
        hid_hw_close(hdev);
        return ret;
}

static int rmi_input_mapping(struct hid_device *hdev,
                struct hid_input *hi, struct hid_field *field,
                struct hid_usage *usage, unsigned long **bit, int *max)
{
        struct rmi_data *data = hid_get_drvdata(hdev);

        /*
         * we want to make HID ignore the advertised HID collection
         * for RMI deivces
         */
        if (data->device_flags & RMI_DEVICE) {
                if ((data->device_flags & RMI_DEVICE_HAS_PHYS_BUTTONS) &&
                    ((usage->hid & HID_USAGE_PAGE) == HID_UP_BUTTON))
                        return 0;

                return -1;
        }

        return 0;
}

static int rmi_check_valid_report_id(struct hid_device *hdev, unsigned type,
                unsigned id, struct hid_report **report)
{
        int i;

        *report = hdev->report_enum[type].report_id_hash[id];
        if (*report) {
                for (i = 0; i < (*report)->maxfield; i++) {
                        unsigned app = (*report)->field[i]->application;
                        if ((app & HID_USAGE_PAGE) >= HID_UP_MSVENDOR)
                                return 1;
                }
        }

        return 0;
}

static struct rmi_device_platform_data rmi_hid_pdata = {
        .sensor_pdata = {
                .sensor_type = rmi_sensor_touchpad,
                .axis_align.flip_y = true,
                .dribble = RMI_REG_STATE_ON,
                .palm_detect = RMI_REG_STATE_OFF,
        },
};

static const struct rmi_transport_ops hid_rmi_ops = {
        .write_block    = rmi_hid_write_block,
        .read_block     = rmi_hid_read_block,
        .reset          = rmi_hid_reset,
};

static void rmi_irq_teardown(void *data)
{
        struct rmi_data *hdata = data;
        struct irq_domain *domain = hdata->domain;

        if (!domain)
                return;

        irq_dispose_mapping(irq_find_mapping(domain, 0));

        irq_domain_remove(domain);
        hdata->domain = NULL;
        hdata->rmi_irq = 0;
}

static int rmi_irq_map(struct irq_domain *h, unsigned int virq,
                       irq_hw_number_t hw_irq_num)
{
        irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);

        return 0;
}

static const struct irq_domain_ops rmi_irq_ops = {
        .map = rmi_irq_map,
};

static int rmi_setup_irq_domain(struct hid_device *hdev)
{
        struct rmi_data *hdata = hid_get_drvdata(hdev);
        int ret;

        hdata->domain = irq_domain_create_linear(hdev->dev.fwnode, 1,
                                                 &rmi_irq_ops, hdata);
        if (!hdata->domain)
                return -ENOMEM;

        ret = devm_add_action_or_reset(&hdev->dev, &rmi_irq_teardown, hdata);
        if (ret)
                return ret;

        hdata->rmi_irq = irq_create_mapping(hdata->domain, 0);
        if (hdata->rmi_irq <= 0) {
                hid_err(hdev, "Can't allocate an IRQ\n");
                return hdata->rmi_irq < 0 ? hdata->rmi_irq : -ENXIO;
        }

        return 0;
}

static int rmi_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
        struct rmi_data *data = NULL;
        int ret;
        size_t alloc_size;
        struct hid_report *input_report;
        struct hid_report *output_report;
        struct hid_report *feature_report;

        data = devm_kzalloc(&hdev->dev, sizeof(struct rmi_data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        INIT_WORK(&data->reset_work, rmi_reset_work);
        data->hdev = hdev;

        hid_set_drvdata(hdev, data);

        hdev->quirks |= HID_QUIRK_NO_INIT_REPORTS;

        ret = hid_parse(hdev);
        if (ret) {
                hid_err(hdev, "parse failed\n");
                return ret;
        }

        if (id->driver_data)
                data->device_flags = id->driver_data;

        /*
         * Check for the RMI specific report ids. If they are misisng
         * simply return and let the events be processed by hid-input
         */
        if (!rmi_check_valid_report_id(hdev, HID_FEATURE_REPORT,
            RMI_SET_RMI_MODE_REPORT_ID, &feature_report)) {
                hid_dbg(hdev, "device does not have set mode feature report\n");
                goto start;
        }

        if (!rmi_check_valid_report_id(hdev, HID_INPUT_REPORT,
            RMI_ATTN_REPORT_ID, &input_report)) {
                hid_dbg(hdev, "device does not have attention input report\n");
                goto start;
        }

        data->input_report_size = hid_report_len(input_report);

        if (!rmi_check_valid_report_id(hdev, HID_OUTPUT_REPORT,
            RMI_WRITE_REPORT_ID, &output_report)) {
                hid_dbg(hdev,
                        "device does not have rmi write output report\n");
                goto start;
        }

        data->output_report_size = hid_report_len(output_report);

        data->device_flags |= RMI_DEVICE;
        alloc_size = data->output_report_size + data->input_report_size;

        data->writeReport = devm_kzalloc(&hdev->dev, alloc_size, GFP_KERNEL);
        if (!data->writeReport) {
                hid_err(hdev, "failed to allocate buffer for HID reports\n");
                return -ENOMEM;
        }

        data->readReport = data->writeReport + data->output_report_size;

        init_waitqueue_head(&data->wait);

        mutex_init(&data->page_mutex);

        ret = rmi_setup_irq_domain(hdev);
        if (ret) {
                hid_err(hdev, "failed to allocate IRQ domain\n");
                return ret;
        }

        if (data->device_flags & RMI_DEVICE_HAS_PHYS_BUTTONS)
                rmi_hid_pdata.f30_data.disable = true;

        data->xport.dev = hdev->dev.parent;
        data->xport.pdata = rmi_hid_pdata;
        data->xport.pdata.irq = data->rmi_irq;
        data->xport.proto_name = "hid";
        data->xport.ops = &hid_rmi_ops;

start:
        ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
        if (ret) {
                hid_err(hdev, "hw start failed\n");
                return ret;
        }

        return 0;
}

static void rmi_remove(struct hid_device *hdev)
{
        struct rmi_data *hdata = hid_get_drvdata(hdev);

        if (hdata->device_flags & RMI_DEVICE) {
                clear_bit(RMI_STARTED, &hdata->flags);
                cancel_work_sync(&hdata->reset_work);
                rmi_unregister_transport_device(&hdata->xport);
        }

        hid_hw_stop(hdev);
}

static const struct hid_device_id rmi_id[] = {
        { HID_USB_DEVICE(USB_VENDOR_ID_RAZER, USB_DEVICE_ID_RAZER_BLADE_14),
                .driver_data = RMI_DEVICE_HAS_PHYS_BUTTONS },
        { HID_USB_DEVICE(USB_VENDOR_ID_LENOVO, USB_DEVICE_ID_LENOVO_X1_COVER) },
        { HID_USB_DEVICE(USB_VENDOR_ID_PRIMAX, USB_DEVICE_ID_PRIMAX_REZEL) },
        { HID_DEVICE(HID_BUS_ANY, HID_GROUP_RMI, HID_ANY_ID, HID_ANY_ID) },
        { }
};
MODULE_DEVICE_TABLE(hid, rmi_id);

static struct hid_driver rmi_driver = {
        .name = "hid-rmi",
        .id_table               = rmi_id,
        .probe                  = rmi_probe,
        .remove                 = rmi_remove,
        .event                  = rmi_event,
        .raw_event              = rmi_raw_event,
        .input_mapping          = rmi_input_mapping,
        .input_configured       = rmi_input_configured,
#ifdef CONFIG_PM
        .suspend                = rmi_suspend,
        .resume                 = rmi_post_resume,
        .reset_resume           = rmi_post_resume,
#endif
};

module_hid_driver(rmi_driver);

MODULE_AUTHOR("Andrew Duggan <aduggan@synaptics.com>");
MODULE_DESCRIPTION("RMI HID driver");
MODULE_LICENSE("GPL");