root/drivers/misc/mei/gsc-me.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright(c) 2019-2022, Intel Corporation. All rights reserved.
 *
 * Intel Management Engine Interface (Intel MEI) Linux driver
 */

#include <linux/module.h>
#include <linux/mei_aux.h>
#include <linux/device.h>
#include <linux/irqreturn.h>
#include <linux/jiffies.h>
#include <linux/ktime.h>
#include <linux/delay.h>
#include <linux/pm_runtime.h>
#include <linux/kthread.h>

#include "mei_dev.h"
#include "hw-me.h"
#include "hw-me-regs.h"

#include "mei-trace.h"

#define MEI_GSC_RPM_TIMEOUT 500

static int mei_gsc_read_hfs(const struct mei_device *dev, int where, u32 *val)
{
        struct mei_me_hw *hw = to_me_hw(dev);

        *val = ioread32(hw->mem_addr + where + 0xC00);

        return 0;
}

static void mei_gsc_set_ext_op_mem(const struct mei_me_hw *hw, struct resource *mem)
{
        u32 low = lower_32_bits(mem->start);
        u32 hi  = upper_32_bits(mem->start);
        u32 limit = (resource_size(mem) / SZ_4K) | GSC_EXT_OP_MEM_VALID;

        iowrite32(low, hw->mem_addr + H_GSC_EXT_OP_MEM_BASE_ADDR_LO_REG);
        iowrite32(hi, hw->mem_addr + H_GSC_EXT_OP_MEM_BASE_ADDR_HI_REG);
        iowrite32(limit, hw->mem_addr + H_GSC_EXT_OP_MEM_LIMIT_REG);
}

static int mei_gsc_probe(struct auxiliary_device *aux_dev,
                         const struct auxiliary_device_id *aux_dev_id)
{
        struct mei_aux_device *adev = auxiliary_dev_to_mei_aux_dev(aux_dev);
        struct mei_device *dev;
        struct mei_me_hw *hw;
        struct device *device;
        const struct mei_cfg *cfg;
        int ret;

        cfg = mei_me_get_cfg(aux_dev_id->driver_data);
        if (!cfg)
                return -ENODEV;

        device = &aux_dev->dev;

        dev = mei_me_dev_init(device, cfg, adev->slow_firmware);
        if (!dev) {
                ret = -ENOMEM;
                goto err;
        }

        hw = to_me_hw(dev);
        hw->mem_addr = devm_ioremap_resource(device, &adev->bar);
        if (IS_ERR(hw->mem_addr)) {
                ret = PTR_ERR(hw->mem_addr);
                goto err;
        }

        hw->irq = adev->irq;
        hw->read_fws = mei_gsc_read_hfs;

        dev_set_drvdata(device, dev);

        if (adev->ext_op_mem.start) {
                mei_gsc_set_ext_op_mem(hw, &adev->ext_op_mem);
                dev->pxp_mode = MEI_DEV_PXP_INIT;
        }

        /* use polling */
        if (mei_me_hw_use_polling(hw)) {
                mei_disable_interrupts(dev);
                mei_clear_interrupts(dev);
                init_waitqueue_head(&hw->wait_active);
                hw->is_active = true; /* start in active mode for initialization */
                hw->polling_thread = kthread_run(mei_me_polling_thread, dev,
                                                 "kmegscirqd/%s", dev_name(device));
                if (IS_ERR(hw->polling_thread)) {
                        ret = PTR_ERR(hw->polling_thread);
                        dev_err(device, "unable to create kernel thread: %d\n", ret);
                        goto err;
                }
        } else {
                ret = devm_request_threaded_irq(device, hw->irq,
                                                mei_me_irq_quick_handler,
                                                mei_me_irq_thread_handler,
                                                IRQF_ONESHOT, KBUILD_MODNAME, dev);
                if (ret) {
                        dev_err(device, "irq register failed %d\n", ret);
                        goto err;
                }
        }

        ret = mei_register(dev, device);
        if (ret)
                goto deinterrupt;

        pm_runtime_get_noresume(device);
        pm_runtime_set_active(device);
        pm_runtime_enable(device);

        /* Continue in spite of firmware handshake failure.
         * In order to provide access to the firmware status registers to the user
         * space via sysfs.
         */
        if (mei_start(dev))
                dev_warn(device, "init hw failure.\n");

        pm_runtime_set_autosuspend_delay(device, MEI_GSC_RPM_TIMEOUT);
        pm_runtime_use_autosuspend(device);

        pm_runtime_put_noidle(device);
        return 0;

deinterrupt:
        if (!mei_me_hw_use_polling(hw))
                devm_free_irq(device, hw->irq, dev);
err:
        dev_err(device, "probe failed: %d\n", ret);
        dev_set_drvdata(device, NULL);
        return ret;
}

static void mei_gsc_remove(struct auxiliary_device *aux_dev)
{
        struct mei_device *dev;
        struct mei_me_hw *hw;

        dev = dev_get_drvdata(&aux_dev->dev);
        hw = to_me_hw(dev);

        mei_stop(dev);

        hw = to_me_hw(dev);
        if (mei_me_hw_use_polling(hw))
                kthread_stop(hw->polling_thread);

        pm_runtime_disable(&aux_dev->dev);

        mei_disable_interrupts(dev);
        if (!mei_me_hw_use_polling(hw))
                devm_free_irq(&aux_dev->dev, hw->irq, dev);

        mei_deregister(dev);
}

static int __maybe_unused mei_gsc_pm_suspend(struct device *device)
{
        struct mei_device *dev = dev_get_drvdata(device);

        mei_stop(dev);

        mei_disable_interrupts(dev);

        return 0;
}

static int __maybe_unused mei_gsc_pm_resume(struct device *device)
{
        struct mei_device *dev = dev_get_drvdata(device);
        struct auxiliary_device *aux_dev;
        struct mei_aux_device *adev;
        int err;
        struct mei_me_hw *hw;

        hw = to_me_hw(dev);
        aux_dev = to_auxiliary_dev(device);
        adev = auxiliary_dev_to_mei_aux_dev(aux_dev);
        if (adev->ext_op_mem.start) {
                mei_gsc_set_ext_op_mem(hw, &adev->ext_op_mem);
                dev->pxp_mode = MEI_DEV_PXP_INIT;
        }

        err = mei_restart(dev);
        if (err)
                return err;

        /* Start timer if stopped in suspend */
        schedule_delayed_work(&dev->timer_work, HZ);

        return 0;
}

static int __maybe_unused mei_gsc_pm_runtime_idle(struct device *device)
{
        struct mei_device *dev = dev_get_drvdata(device);

        if (mei_write_is_idle(dev))
                pm_runtime_autosuspend(device);

        return -EBUSY;
}

static int  __maybe_unused mei_gsc_pm_runtime_suspend(struct device *device)
{
        struct mei_device *dev = dev_get_drvdata(device);
        struct mei_me_hw *hw;
        int ret;

        mutex_lock(&dev->device_lock);

        if (mei_write_is_idle(dev)) {
                hw = to_me_hw(dev);
                hw->pg_state = MEI_PG_ON;

                if (mei_me_hw_use_polling(hw))
                        hw->is_active = false;
                ret = 0;
        } else {
                ret = -EAGAIN;
        }

        mutex_unlock(&dev->device_lock);

        return ret;
}

static int __maybe_unused mei_gsc_pm_runtime_resume(struct device *device)
{
        struct mei_device *dev = dev_get_drvdata(device);
        struct mei_me_hw *hw;
        irqreturn_t irq_ret;

        mutex_lock(&dev->device_lock);

        hw = to_me_hw(dev);
        hw->pg_state = MEI_PG_OFF;

        if (mei_me_hw_use_polling(hw)) {
                hw->is_active = true;
                wake_up(&hw->wait_active);
        }

        mutex_unlock(&dev->device_lock);

        irq_ret = mei_me_irq_thread_handler(1, dev);
        if (irq_ret != IRQ_HANDLED)
                dev_err(&dev->dev, "thread handler fail %d\n", irq_ret);

        return 0;
}

static const struct dev_pm_ops mei_gsc_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(mei_gsc_pm_suspend,
                                mei_gsc_pm_resume)
        SET_RUNTIME_PM_OPS(mei_gsc_pm_runtime_suspend,
                           mei_gsc_pm_runtime_resume,
                           mei_gsc_pm_runtime_idle)
};

static const struct auxiliary_device_id mei_gsc_id_table[] = {
        {
                .name = "i915.mei-gsc",
                .driver_data = MEI_ME_GSC_CFG,

        },
        {
                .name = "i915.mei-gscfi",
                .driver_data = MEI_ME_GSCFI_CFG,
        },
        {
                .name = "xe.mei-gscfi",
                .driver_data = MEI_ME_GSCFI_CFG,
        },
        {
                /* sentinel */
        }
};
MODULE_DEVICE_TABLE(auxiliary, mei_gsc_id_table);

static struct auxiliary_driver mei_gsc_driver = {
        .probe  = mei_gsc_probe,
        .remove = mei_gsc_remove,
        .driver = {
                /* auxiliary_driver_register() sets .name to be the modname */
                .pm = &mei_gsc_pm_ops,
        },
        .id_table = mei_gsc_id_table
};
module_auxiliary_driver(mei_gsc_driver);

MODULE_AUTHOR("Intel Corporation");
MODULE_ALIAS("auxiliary:i915.mei-gsc");
MODULE_ALIAS("auxiliary:i915.mei-gscfi");
MODULE_ALIAS("auxiliary:xe.mei-gscfi");
MODULE_DESCRIPTION("Intel(R) Graphics System Controller");
MODULE_LICENSE("GPL");