// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2022-2023 Intel Corporation
 */

/**
 * DOC: MEI_GSC_PROXY Client Driver
 *
 * The mei_gsc_proxy driver acts as a translation layer between
 * proxy user (I915) and ME FW by proxying messages to ME FW
 */

#include <linux/component.h>
#include <linux/mei_cl_bus.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/uuid.h>
#include <drm/drm_connector.h>
#include <drm/intel/i915_component.h>
#include <drm/intel/i915_gsc_proxy_mei_interface.h>

/**
 * mei_gsc_proxy_send - Sends a proxy message to ME FW.
 * @dev: device corresponding to the mei_cl_device
 * @buf: a message buffer to send
 * @size: size of the message
 * Return: bytes sent on Success, <0 on Failure
 */
static int mei_gsc_proxy_send(struct device *dev, const void *buf, size_t size)
{
        ssize_t ret;

        if (!dev || !buf)
                return -EINVAL;

        ret = mei_cldev_send(to_mei_cl_device(dev), buf, size);
        if (ret < 0)
                dev_dbg(dev, "mei_cldev_send failed. %zd\n", ret);

        return ret;
}

/**
 * mei_gsc_proxy_recv - Receives a proxy message from ME FW.
 * @dev: device corresponding to the mei_cl_device
 * @buf: a message buffer to contain the received message
 * @size: size of the buffer
 * Return: bytes received on Success, <0 on Failure
 */
static int mei_gsc_proxy_recv(struct device *dev, void *buf, size_t size)
{
        ssize_t ret;

        if (!dev || !buf)
                return -EINVAL;

        ret = mei_cldev_recv(to_mei_cl_device(dev), buf, size);
        if (ret < 0)
                dev_dbg(dev, "mei_cldev_recv failed. %zd\n", ret);

        return ret;
}

static const struct i915_gsc_proxy_component_ops mei_gsc_proxy_ops = {
        .owner = THIS_MODULE,
        .send = mei_gsc_proxy_send,
        .recv = mei_gsc_proxy_recv,
};

static int mei_component_master_bind(struct device *dev)
{
        struct mei_cl_device *cldev = to_mei_cl_device(dev);
        struct i915_gsc_proxy_component *comp_master = mei_cldev_get_drvdata(cldev);

        comp_master->ops = &mei_gsc_proxy_ops;
        comp_master->mei_dev = dev;
        return component_bind_all(dev, comp_master);
}

static void mei_component_master_unbind(struct device *dev)
{
        struct mei_cl_device *cldev = to_mei_cl_device(dev);
        struct i915_gsc_proxy_component *comp_master = mei_cldev_get_drvdata(cldev);

        component_unbind_all(dev, comp_master);
}

static const struct component_master_ops mei_component_master_ops = {
        .bind = mei_component_master_bind,
        .unbind = mei_component_master_unbind,
};

/**
 * mei_gsc_proxy_component_match - compare function for matching mei.
 *
 *    The function checks if the device is pci device and
 *    Intel VGA adapter, the subcomponent is SW Proxy
 *    and the VGA is on the bus 0 reserved for built-in devices
 *    to reject discrete GFX.
 *
 * @dev: master device
 * @subcomponent: subcomponent to match (I915_COMPONENT_SWPROXY)
 * @data: compare data (mei pci parent)
 *
 * Return:
 * * 1 - if components match
 * * 0 - otherwise
 */
static int mei_gsc_proxy_component_match(struct device *dev, int subcomponent,
                                         void *data)
{
        struct pci_dev *pdev;

        if (!dev_is_pci(dev))
                return 0;

        pdev = to_pci_dev(dev);

        if (pdev->class != (PCI_CLASS_DISPLAY_VGA << 8) ||
            pdev->vendor != PCI_VENDOR_ID_INTEL)
                return 0;

        if (subcomponent != I915_COMPONENT_GSC_PROXY)
                return 0;

        /* Only built-in GFX */
        return (pdev->bus->number == 0);
}

static int mei_gsc_proxy_probe(struct mei_cl_device *cldev,
                               const struct mei_cl_device_id *id)
{
        struct i915_gsc_proxy_component *comp_master;
        struct component_match *master_match = NULL;
        int ret;

        ret = mei_cldev_enable(cldev);
        if (ret < 0) {
                dev_err(&cldev->dev, "mei_cldev_enable Failed. %d\n", ret);
                goto enable_err_exit;
        }

        comp_master = kzalloc_obj(*comp_master);
        if (!comp_master) {
                ret = -ENOMEM;
                goto err_exit;
        }

        component_match_add_typed(&cldev->dev, &master_match,
                                  mei_gsc_proxy_component_match, NULL);
        if (IS_ERR_OR_NULL(master_match)) {
                ret = -ENOMEM;
                goto err_exit;
        }

        mei_cldev_set_drvdata(cldev, comp_master);
        ret = component_master_add_with_match(&cldev->dev,
                                              &mei_component_master_ops,
                                              master_match);
        if (ret < 0) {
                dev_err(&cldev->dev, "Master comp add failed %d\n", ret);
                goto err_exit;
        }

        return 0;

err_exit:
        mei_cldev_set_drvdata(cldev, NULL);
        kfree(comp_master);
        mei_cldev_disable(cldev);
enable_err_exit:
        return ret;
}

static void mei_gsc_proxy_remove(struct mei_cl_device *cldev)
{
        struct i915_gsc_proxy_component *comp_master = mei_cldev_get_drvdata(cldev);
        int ret;

        component_master_del(&cldev->dev, &mei_component_master_ops);
        kfree(comp_master);
        mei_cldev_set_drvdata(cldev, NULL);

        ret = mei_cldev_disable(cldev);
        if (ret)
                dev_warn(&cldev->dev, "mei_cldev_disable() failed %d\n", ret);
}

#define MEI_UUID_GSC_PROXY UUID_LE(0xf73db04, 0x97ab, 0x4125, \
                                   0xb8, 0x93, 0xe9, 0x4, 0xad, 0xd, 0x54, 0x64)

static struct mei_cl_device_id mei_gsc_proxy_tbl[] = {
        { .uuid = MEI_UUID_GSC_PROXY, .version = MEI_CL_VERSION_ANY },
        { }
};
MODULE_DEVICE_TABLE(mei, mei_gsc_proxy_tbl);

static struct mei_cl_driver mei_gsc_proxy_driver = {
        .id_table = mei_gsc_proxy_tbl,
        .name = KBUILD_MODNAME,
        .probe = mei_gsc_proxy_probe,
        .remove = mei_gsc_proxy_remove,
};

module_mei_cl_driver(mei_gsc_proxy_driver);

MODULE_AUTHOR("Intel Corporation");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("MEI GSC PROXY");