/*
 *
 * Intel Management Engine Interface (Intel MEI) Linux driver
 * Copyright (c) 2003-2012, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 */

#include <linux/pci.h>

#include <linux/kthread.h>
#include <linux/interrupt.h>
#include <linux/pm_runtime.h>

#include "mei_dev.h"
#include "hbm.h"

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

#include "mei-trace.h"

/**
 * mei_me_reg_read - Reads 32bit data from the mei device
 *
 * @hw: the me hardware structure
 * @offset: offset from which to read the data
 *
 * Return: register value (u32)
 */
static inline u32 mei_me_reg_read(const struct mei_me_hw *hw,
                               unsigned long offset)
{
        return ioread32(hw->mem_addr + offset);
}


/**
 * mei_me_reg_write - Writes 32bit data to the mei device
 *
 * @hw: the me hardware structure
 * @offset: offset from which to write the data
 * @value: register value to write (u32)
 */
static inline void mei_me_reg_write(const struct mei_me_hw *hw,
                                 unsigned long offset, u32 value)
{
        iowrite32(value, hw->mem_addr + offset);
}

/**
 * mei_me_mecbrw_read - Reads 32bit data from ME circular buffer
 *  read window register
 *
 * @dev: the device structure
 *
 * Return: ME_CB_RW register value (u32)
 */
static inline u32 mei_me_mecbrw_read(const struct mei_device *dev)
{
        return mei_me_reg_read(to_me_hw(dev), ME_CB_RW);
}

/**
 * mei_me_hcbww_write - write 32bit data to the host circular buffer
 *
 * @dev: the device structure
 * @data: 32bit data to be written to the host circular buffer
 */
static inline void mei_me_hcbww_write(struct mei_device *dev, u32 data)
{
        mei_me_reg_write(to_me_hw(dev), H_CB_WW, data);
}

/**
 * mei_me_mecsr_read - Reads 32bit data from the ME CSR
 *
 * @dev: the device structure
 *
 * Return: ME_CSR_HA register value (u32)
 */
static inline u32 mei_me_mecsr_read(const struct mei_device *dev)
{
        u32 reg;

        reg = mei_me_reg_read(to_me_hw(dev), ME_CSR_HA);
        trace_mei_reg_read(dev->dev, "ME_CSR_HA", ME_CSR_HA, reg);

        return reg;
}

/**
 * mei_hcsr_read - Reads 32bit data from the host CSR
 *
 * @dev: the device structure
 *
 * Return: H_CSR register value (u32)
 */
static inline u32 mei_hcsr_read(const struct mei_device *dev)
{
        u32 reg;

        reg = mei_me_reg_read(to_me_hw(dev), H_CSR);
        trace_mei_reg_read(dev->dev, "H_CSR", H_CSR, reg);

        return reg;
}

/**
 * mei_hcsr_write - writes H_CSR register to the mei device
 *
 * @dev: the device structure
 * @reg: new register value
 */
static inline void mei_hcsr_write(struct mei_device *dev, u32 reg)
{
        trace_mei_reg_write(dev->dev, "H_CSR", H_CSR, reg);
        mei_me_reg_write(to_me_hw(dev), H_CSR, reg);
}

/**
 * mei_hcsr_set - writes H_CSR register to the mei device,
 * and ignores the H_IS bit for it is write-one-to-zero.
 *
 * @dev: the device structure
 * @reg: new register value
 */
static inline void mei_hcsr_set(struct mei_device *dev, u32 reg)
{
        reg &= ~H_CSR_IS_MASK;
        mei_hcsr_write(dev, reg);
}

/**
 * mei_me_d0i3c_read - Reads 32bit data from the D0I3C register
 *
 * @dev: the device structure
 *
 * Return: H_D0I3C register value (u32)
 */
static inline u32 mei_me_d0i3c_read(const struct mei_device *dev)
{
        u32 reg;

        reg = mei_me_reg_read(to_me_hw(dev), H_D0I3C);
        trace_mei_reg_read(dev->dev, "H_D0I3C", H_D0I3C, reg);

        return reg;
}

/**
 * mei_me_d0i3c_write - writes H_D0I3C register to device
 *
 * @dev: the device structure
 * @reg: new register value
 */
static inline void mei_me_d0i3c_write(struct mei_device *dev, u32 reg)
{
        trace_mei_reg_write(dev->dev, "H_D0I3C", H_D0I3C, reg);
        mei_me_reg_write(to_me_hw(dev), H_D0I3C, reg);
}

/**
 * mei_me_fw_status - read fw status register from pci config space
 *
 * @dev: mei device
 * @fw_status: fw status register values
 *
 * Return: 0 on success, error otherwise
 */
static int mei_me_fw_status(struct mei_device *dev,
                            struct mei_fw_status *fw_status)
{
        struct pci_dev *pdev = to_pci_dev(dev->dev);
        struct mei_me_hw *hw = to_me_hw(dev);
        const struct mei_fw_status *fw_src = &hw->cfg->fw_status;
        int ret;
        int i;

        if (!fw_status)
                return -EINVAL;

        fw_status->count = fw_src->count;
        for (i = 0; i < fw_src->count && i < MEI_FW_STATUS_MAX; i++) {
                ret = pci_read_config_dword(pdev, fw_src->status[i],
                                            &fw_status->status[i]);
                trace_mei_pci_cfg_read(dev->dev, "PCI_CFG_HSF_X",
                                       fw_src->status[i],
                                       fw_status->status[i]);
                if (ret)
                        return ret;
        }

        return 0;
}

/**
 * mei_me_hw_config - configure hw dependent settings
 *
 * @dev: mei device
 */
static void mei_me_hw_config(struct mei_device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev->dev);
        struct mei_me_hw *hw = to_me_hw(dev);
        u32 hcsr, reg;

        /* Doesn't change in runtime */
        hcsr = mei_hcsr_read(dev);
        dev->hbuf_depth = (hcsr & H_CBD) >> 24;

        reg = 0;
        pci_read_config_dword(pdev, PCI_CFG_HFS_1, &reg);
        trace_mei_pci_cfg_read(dev->dev, "PCI_CFG_HFS_1", PCI_CFG_HFS_1, reg);
        hw->d0i3_supported =
                ((reg & PCI_CFG_HFS_1_D0I3_MSK) == PCI_CFG_HFS_1_D0I3_MSK);

        hw->pg_state = MEI_PG_OFF;
        if (hw->d0i3_supported) {
                reg = mei_me_d0i3c_read(dev);
                if (reg & H_D0I3C_I3)
                        hw->pg_state = MEI_PG_ON;
        }
}

/**
 * mei_me_pg_state  - translate internal pg state
 *   to the mei power gating state
 *
 * @dev:  mei device
 *
 * Return: MEI_PG_OFF if aliveness is on and MEI_PG_ON otherwise
 */
static inline enum mei_pg_state mei_me_pg_state(struct mei_device *dev)
{
        struct mei_me_hw *hw = to_me_hw(dev);

        return hw->pg_state;
}

/**
 * mei_me_intr_clear - clear and stop interrupts
 *
 * @dev: the device structure
 */
static void mei_me_intr_clear(struct mei_device *dev)
{
        u32 hcsr = mei_hcsr_read(dev);

        if (hcsr & H_CSR_IS_MASK)
                mei_hcsr_write(dev, hcsr);
}
/**
 * mei_me_intr_enable - enables mei device interrupts
 *
 * @dev: the device structure
 */
static void mei_me_intr_enable(struct mei_device *dev)
{
        u32 hcsr = mei_hcsr_read(dev);

        hcsr |= H_CSR_IE_MASK;
        mei_hcsr_set(dev, hcsr);
}

/**
 * mei_me_intr_disable - disables mei device interrupts
 *
 * @dev: the device structure
 */
static void mei_me_intr_disable(struct mei_device *dev)
{
        u32 hcsr = mei_hcsr_read(dev);

        hcsr  &= ~H_CSR_IE_MASK;
        mei_hcsr_set(dev, hcsr);
}

/**
 * mei_me_hw_reset_release - release device from the reset
 *
 * @dev: the device structure
 */
static void mei_me_hw_reset_release(struct mei_device *dev)
{
        u32 hcsr = mei_hcsr_read(dev);

        hcsr |= H_IG;
        hcsr &= ~H_RST;
        mei_hcsr_set(dev, hcsr);

        /* complete this write before we set host ready on another CPU */
        mmiowb();
}

/**
 * mei_me_host_set_ready - enable device
 *
 * @dev: mei device
 */
static void mei_me_host_set_ready(struct mei_device *dev)
{
        u32 hcsr = mei_hcsr_read(dev);

        hcsr |= H_CSR_IE_MASK | H_IG | H_RDY;
        mei_hcsr_set(dev, hcsr);
}

/**
 * mei_me_host_is_ready - check whether the host has turned ready
 *
 * @dev: mei device
 * Return: bool
 */
static bool mei_me_host_is_ready(struct mei_device *dev)
{
        u32 hcsr = mei_hcsr_read(dev);

        return (hcsr & H_RDY) == H_RDY;
}

/**
 * mei_me_hw_is_ready - check whether the me(hw) has turned ready
 *
 * @dev: mei device
 * Return: bool
 */
static bool mei_me_hw_is_ready(struct mei_device *dev)
{
        u32 mecsr = mei_me_mecsr_read(dev);

        return (mecsr & ME_RDY_HRA) == ME_RDY_HRA;
}

/**
 * mei_me_hw_ready_wait - wait until the me(hw) has turned ready
 *  or timeout is reached
 *
 * @dev: mei device
 * Return: 0 on success, error otherwise
 */
static int mei_me_hw_ready_wait(struct mei_device *dev)
{
        mutex_unlock(&dev->device_lock);
        wait_event_timeout(dev->wait_hw_ready,
                        dev->recvd_hw_ready,
                        mei_secs_to_jiffies(MEI_HW_READY_TIMEOUT));
        mutex_lock(&dev->device_lock);
        if (!dev->recvd_hw_ready) {
                dev_err(dev->dev, "wait hw ready failed\n");
                return -ETIME;
        }

        mei_me_hw_reset_release(dev);
        dev->recvd_hw_ready = false;
        return 0;
}

/**
 * mei_me_hw_start - hw start routine
 *
 * @dev: mei device
 * Return: 0 on success, error otherwise
 */
static int mei_me_hw_start(struct mei_device *dev)
{
        int ret = mei_me_hw_ready_wait(dev);

        if (ret)
                return ret;
        dev_dbg(dev->dev, "hw is ready\n");

        mei_me_host_set_ready(dev);
        return ret;
}


/**
 * mei_hbuf_filled_slots - gets number of device filled buffer slots
 *
 * @dev: the device structure
 *
 * Return: number of filled slots
 */
static unsigned char mei_hbuf_filled_slots(struct mei_device *dev)
{
        u32 hcsr;
        char read_ptr, write_ptr;

        hcsr = mei_hcsr_read(dev);

        read_ptr = (char) ((hcsr & H_CBRP) >> 8);
        write_ptr = (char) ((hcsr & H_CBWP) >> 16);

        return (unsigned char) (write_ptr - read_ptr);
}

/**
 * mei_me_hbuf_is_empty - checks if host buffer is empty.
 *
 * @dev: the device structure
 *
 * Return: true if empty, false - otherwise.
 */
static bool mei_me_hbuf_is_empty(struct mei_device *dev)
{
        return mei_hbuf_filled_slots(dev) == 0;
}

/**
 * mei_me_hbuf_empty_slots - counts write empty slots.
 *
 * @dev: the device structure
 *
 * Return: -EOVERFLOW if overflow, otherwise empty slots count
 */
static int mei_me_hbuf_empty_slots(struct mei_device *dev)
{
        unsigned char filled_slots, empty_slots;

        filled_slots = mei_hbuf_filled_slots(dev);
        empty_slots = dev->hbuf_depth - filled_slots;

        /* check for overflow */
        if (filled_slots > dev->hbuf_depth)
                return -EOVERFLOW;

        return empty_slots;
}

/**
 * mei_me_hbuf_max_len - returns size of hw buffer.
 *
 * @dev: the device structure
 *
 * Return: size of hw buffer in bytes
 */
static size_t mei_me_hbuf_max_len(const struct mei_device *dev)
{
        return dev->hbuf_depth * sizeof(u32) - sizeof(struct mei_msg_hdr);
}


/**
 * mei_me_write_message - writes a message to mei device.
 *
 * @dev: the device structure
 * @header: mei HECI header of message
 * @buf: message payload will be written
 *
 * Return: -EIO if write has failed
 */
static int mei_me_write_message(struct mei_device *dev,
                        struct mei_msg_hdr *header,
                        unsigned char *buf)
{
        unsigned long rem;
        unsigned long length = header->length;
        u32 *reg_buf = (u32 *)buf;
        u32 hcsr;
        u32 dw_cnt;
        int i;
        int empty_slots;

        dev_dbg(dev->dev, MEI_HDR_FMT, MEI_HDR_PRM(header));

        empty_slots = mei_hbuf_empty_slots(dev);
        dev_dbg(dev->dev, "empty slots = %hu.\n", empty_slots);

        dw_cnt = mei_data2slots(length);
        if (empty_slots < 0 || dw_cnt > empty_slots)
                return -EMSGSIZE;

        mei_me_hcbww_write(dev, *((u32 *) header));

        for (i = 0; i < length / 4; i++)
                mei_me_hcbww_write(dev, reg_buf[i]);

        rem = length & 0x3;
        if (rem > 0) {
                u32 reg = 0;

                memcpy(&reg, &buf[length - rem], rem);
                mei_me_hcbww_write(dev, reg);
        }

        hcsr = mei_hcsr_read(dev) | H_IG;
        mei_hcsr_set(dev, hcsr);
        if (!mei_me_hw_is_ready(dev))
                return -EIO;

        return 0;
}

/**
 * mei_me_count_full_read_slots - counts read full slots.
 *
 * @dev: the device structure
 *
 * Return: -EOVERFLOW if overflow, otherwise filled slots count
 */
static int mei_me_count_full_read_slots(struct mei_device *dev)
{
        u32 me_csr;
        char read_ptr, write_ptr;
        unsigned char buffer_depth, filled_slots;

        me_csr = mei_me_mecsr_read(dev);
        buffer_depth = (unsigned char)((me_csr & ME_CBD_HRA) >> 24);
        read_ptr = (char) ((me_csr & ME_CBRP_HRA) >> 8);
        write_ptr = (char) ((me_csr & ME_CBWP_HRA) >> 16);
        filled_slots = (unsigned char) (write_ptr - read_ptr);

        /* check for overflow */
        if (filled_slots > buffer_depth)
                return -EOVERFLOW;

        dev_dbg(dev->dev, "filled_slots =%08x\n", filled_slots);
        return (int)filled_slots;
}

/**
 * mei_me_read_slots - reads a message from mei device.
 *
 * @dev: the device structure
 * @buffer: message buffer will be written
 * @buffer_length: message size will be read
 *
 * Return: always 0
 */
static int mei_me_read_slots(struct mei_device *dev, unsigned char *buffer,
                    unsigned long buffer_length)
{
        u32 *reg_buf = (u32 *)buffer;
        u32 hcsr;

        for (; buffer_length >= sizeof(u32); buffer_length -= sizeof(u32))
                *reg_buf++ = mei_me_mecbrw_read(dev);

        if (buffer_length > 0) {
                u32 reg = mei_me_mecbrw_read(dev);

                memcpy(reg_buf, &reg, buffer_length);
        }

        hcsr = mei_hcsr_read(dev) | H_IG;
        mei_hcsr_set(dev, hcsr);
        return 0;
}

/**
 * mei_me_pg_set - write pg enter register
 *
 * @dev: the device structure
 */
static void mei_me_pg_set(struct mei_device *dev)
{
        struct mei_me_hw *hw = to_me_hw(dev);
        u32 reg;

        reg = mei_me_reg_read(hw, H_HPG_CSR);
        trace_mei_reg_read(dev->dev, "H_HPG_CSR", H_HPG_CSR, reg);

        reg |= H_HPG_CSR_PGI;

        trace_mei_reg_write(dev->dev, "H_HPG_CSR", H_HPG_CSR, reg);
        mei_me_reg_write(hw, H_HPG_CSR, reg);
}

/**
 * mei_me_pg_unset - write pg exit register
 *
 * @dev: the device structure
 */
static void mei_me_pg_unset(struct mei_device *dev)
{
        struct mei_me_hw *hw = to_me_hw(dev);
        u32 reg;

        reg = mei_me_reg_read(hw, H_HPG_CSR);
        trace_mei_reg_read(dev->dev, "H_HPG_CSR", H_HPG_CSR, reg);

        WARN(!(reg & H_HPG_CSR_PGI), "PGI is not set\n");

        reg |= H_HPG_CSR_PGIHEXR;

        trace_mei_reg_write(dev->dev, "H_HPG_CSR", H_HPG_CSR, reg);
        mei_me_reg_write(hw, H_HPG_CSR, reg);
}

/**
 * mei_me_pg_legacy_enter_sync - perform legacy pg entry procedure
 *
 * @dev: the device structure
 *
 * Return: 0 on success an error code otherwise
 */
static int mei_me_pg_legacy_enter_sync(struct mei_device *dev)
{
        struct mei_me_hw *hw = to_me_hw(dev);
        unsigned long timeout = mei_secs_to_jiffies(MEI_PGI_TIMEOUT);
        int ret;

        dev->pg_event = MEI_PG_EVENT_WAIT;

        ret = mei_hbm_pg(dev, MEI_PG_ISOLATION_ENTRY_REQ_CMD);
        if (ret)
                return ret;

        mutex_unlock(&dev->device_lock);
        wait_event_timeout(dev->wait_pg,
                dev->pg_event == MEI_PG_EVENT_RECEIVED, timeout);
        mutex_lock(&dev->device_lock);

        if (dev->pg_event == MEI_PG_EVENT_RECEIVED) {
                mei_me_pg_set(dev);
                ret = 0;
        } else {
                ret = -ETIME;
        }

        dev->pg_event = MEI_PG_EVENT_IDLE;
        hw->pg_state = MEI_PG_ON;

        return ret;
}

/**
 * mei_me_pg_legacy_exit_sync - perform legacy pg exit procedure
 *
 * @dev: the device structure
 *
 * Return: 0 on success an error code otherwise
 */
static int mei_me_pg_legacy_exit_sync(struct mei_device *dev)
{
        struct mei_me_hw *hw = to_me_hw(dev);
        unsigned long timeout = mei_secs_to_jiffies(MEI_PGI_TIMEOUT);
        int ret;

        if (dev->pg_event == MEI_PG_EVENT_RECEIVED)
                goto reply;

        dev->pg_event = MEI_PG_EVENT_WAIT;

        mei_me_pg_unset(dev);

        mutex_unlock(&dev->device_lock);
        wait_event_timeout(dev->wait_pg,
                dev->pg_event == MEI_PG_EVENT_RECEIVED, timeout);
        mutex_lock(&dev->device_lock);

reply:
        if (dev->pg_event != MEI_PG_EVENT_RECEIVED) {
                ret = -ETIME;
                goto out;
        }

        dev->pg_event = MEI_PG_EVENT_INTR_WAIT;
        ret = mei_hbm_pg(dev, MEI_PG_ISOLATION_EXIT_RES_CMD);
        if (ret)
                return ret;

        mutex_unlock(&dev->device_lock);
        wait_event_timeout(dev->wait_pg,
                dev->pg_event == MEI_PG_EVENT_INTR_RECEIVED, timeout);
        mutex_lock(&dev->device_lock);

        if (dev->pg_event == MEI_PG_EVENT_INTR_RECEIVED)
                ret = 0;
        else
                ret = -ETIME;

out:
        dev->pg_event = MEI_PG_EVENT_IDLE;
        hw->pg_state = MEI_PG_OFF;

        return ret;
}

/**
 * mei_me_pg_in_transition - is device now in pg transition
 *
 * @dev: the device structure
 *
 * Return: true if in pg transition, false otherwise
 */
static bool mei_me_pg_in_transition(struct mei_device *dev)
{
        return dev->pg_event >= MEI_PG_EVENT_WAIT &&
               dev->pg_event <= MEI_PG_EVENT_INTR_WAIT;
}

/**
 * mei_me_pg_is_enabled - detect if PG is supported by HW
 *
 * @dev: the device structure
 *
 * Return: true is pg supported, false otherwise
 */
static bool mei_me_pg_is_enabled(struct mei_device *dev)
{
        struct mei_me_hw *hw = to_me_hw(dev);
        u32 reg = mei_me_mecsr_read(dev);

        if (hw->d0i3_supported)
                return true;

        if ((reg & ME_PGIC_HRA) == 0)
                goto notsupported;

        if (!dev->hbm_f_pg_supported)
                goto notsupported;

        return true;

notsupported:
        dev_dbg(dev->dev, "pg: not supported: d0i3 = %d HGP = %d hbm version %d.%d ?= %d.%d\n",
                hw->d0i3_supported,
                !!(reg & ME_PGIC_HRA),
                dev->version.major_version,
                dev->version.minor_version,
                HBM_MAJOR_VERSION_PGI,
                HBM_MINOR_VERSION_PGI);

        return false;
}

/**
 * mei_me_d0i3_set - write d0i3 register bit on mei device.
 *
 * @dev: the device structure
 * @intr: ask for interrupt
 *
 * Return: D0I3C register value
 */
static u32 mei_me_d0i3_set(struct mei_device *dev, bool intr)
{
        u32 reg = mei_me_d0i3c_read(dev);

        reg |= H_D0I3C_I3;
        if (intr)
                reg |= H_D0I3C_IR;
        else
                reg &= ~H_D0I3C_IR;
        mei_me_d0i3c_write(dev, reg);
        /* read it to ensure HW consistency */
        reg = mei_me_d0i3c_read(dev);
        return reg;
}

/**
 * mei_me_d0i3_unset - clean d0i3 register bit on mei device.
 *
 * @dev: the device structure
 *
 * Return: D0I3C register value
 */
static u32 mei_me_d0i3_unset(struct mei_device *dev)
{
        u32 reg = mei_me_d0i3c_read(dev);

        reg &= ~H_D0I3C_I3;
        reg |= H_D0I3C_IR;
        mei_me_d0i3c_write(dev, reg);
        /* read it to ensure HW consistency */
        reg = mei_me_d0i3c_read(dev);
        return reg;
}

/**
 * mei_me_d0i3_enter_sync - perform d0i3 entry procedure
 *
 * @dev: the device structure
 *
 * Return: 0 on success an error code otherwise
 */
static int mei_me_d0i3_enter_sync(struct mei_device *dev)
{
        struct mei_me_hw *hw = to_me_hw(dev);
        unsigned long d0i3_timeout = mei_secs_to_jiffies(MEI_D0I3_TIMEOUT);
        unsigned long pgi_timeout = mei_secs_to_jiffies(MEI_PGI_TIMEOUT);
        int ret;
        u32 reg;

        reg = mei_me_d0i3c_read(dev);
        if (reg & H_D0I3C_I3) {
                /* we are in d0i3, nothing to do */
                dev_dbg(dev->dev, "d0i3 set not needed\n");
                ret = 0;
                goto on;
        }

        /* PGI entry procedure */
        dev->pg_event = MEI_PG_EVENT_WAIT;

        ret = mei_hbm_pg(dev, MEI_PG_ISOLATION_ENTRY_REQ_CMD);
        if (ret)
                /* FIXME: should we reset here? */
                goto out;

        mutex_unlock(&dev->device_lock);
        wait_event_timeout(dev->wait_pg,
                dev->pg_event == MEI_PG_EVENT_RECEIVED, pgi_timeout);
        mutex_lock(&dev->device_lock);

        if (dev->pg_event != MEI_PG_EVENT_RECEIVED) {
                ret = -ETIME;
                goto out;
        }
        /* end PGI entry procedure */

        dev->pg_event = MEI_PG_EVENT_INTR_WAIT;

        reg = mei_me_d0i3_set(dev, true);
        if (!(reg & H_D0I3C_CIP)) {
                dev_dbg(dev->dev, "d0i3 enter wait not needed\n");
                ret = 0;
                goto on;
        }

        mutex_unlock(&dev->device_lock);
        wait_event_timeout(dev->wait_pg,
                dev->pg_event == MEI_PG_EVENT_INTR_RECEIVED, d0i3_timeout);
        mutex_lock(&dev->device_lock);

        if (dev->pg_event != MEI_PG_EVENT_INTR_RECEIVED) {
                reg = mei_me_d0i3c_read(dev);
                if (!(reg & H_D0I3C_I3)) {
                        ret = -ETIME;
                        goto out;
                }
        }

        ret = 0;
on:
        hw->pg_state = MEI_PG_ON;
out:
        dev->pg_event = MEI_PG_EVENT_IDLE;
        dev_dbg(dev->dev, "d0i3 enter ret = %d\n", ret);
        return ret;
}

/**
 * mei_me_d0i3_enter - perform d0i3 entry procedure
 *   no hbm PG handshake
 *   no waiting for confirmation; runs with interrupts
 *   disabled
 *
 * @dev: the device structure
 *
 * Return: 0 on success an error code otherwise
 */
static int mei_me_d0i3_enter(struct mei_device *dev)
{
        struct mei_me_hw *hw = to_me_hw(dev);
        u32 reg;

        reg = mei_me_d0i3c_read(dev);
        if (reg & H_D0I3C_I3) {
                /* we are in d0i3, nothing to do */
                dev_dbg(dev->dev, "already d0i3 : set not needed\n");
                goto on;
        }

        mei_me_d0i3_set(dev, false);
on:
        hw->pg_state = MEI_PG_ON;
        dev->pg_event = MEI_PG_EVENT_IDLE;
        dev_dbg(dev->dev, "d0i3 enter\n");
        return 0;
}

/**
 * mei_me_d0i3_exit_sync - perform d0i3 exit procedure
 *
 * @dev: the device structure
 *
 * Return: 0 on success an error code otherwise
 */
static int mei_me_d0i3_exit_sync(struct mei_device *dev)
{
        struct mei_me_hw *hw = to_me_hw(dev);
        unsigned long timeout = mei_secs_to_jiffies(MEI_D0I3_TIMEOUT);
        int ret;
        u32 reg;

        dev->pg_event = MEI_PG_EVENT_INTR_WAIT;

        reg = mei_me_d0i3c_read(dev);
        if (!(reg & H_D0I3C_I3)) {
                /* we are not in d0i3, nothing to do */
                dev_dbg(dev->dev, "d0i3 exit not needed\n");
                ret = 0;
                goto off;
        }

        reg = mei_me_d0i3_unset(dev);
        if (!(reg & H_D0I3C_CIP)) {
                dev_dbg(dev->dev, "d0i3 exit wait not needed\n");
                ret = 0;
                goto off;
        }

        mutex_unlock(&dev->device_lock);
        wait_event_timeout(dev->wait_pg,
                dev->pg_event == MEI_PG_EVENT_INTR_RECEIVED, timeout);
        mutex_lock(&dev->device_lock);

        if (dev->pg_event != MEI_PG_EVENT_INTR_RECEIVED) {
                reg = mei_me_d0i3c_read(dev);
                if (reg & H_D0I3C_I3) {
                        ret = -ETIME;
                        goto out;
                }
        }

        ret = 0;
off:
        hw->pg_state = MEI_PG_OFF;
out:
        dev->pg_event = MEI_PG_EVENT_IDLE;

        dev_dbg(dev->dev, "d0i3 exit ret = %d\n", ret);
        return ret;
}

/**
 * mei_me_pg_legacy_intr - perform legacy pg processing
 *                         in interrupt thread handler
 *
 * @dev: the device structure
 */
static void mei_me_pg_legacy_intr(struct mei_device *dev)
{
        struct mei_me_hw *hw = to_me_hw(dev);

        if (dev->pg_event != MEI_PG_EVENT_INTR_WAIT)
                return;

        dev->pg_event = MEI_PG_EVENT_INTR_RECEIVED;
        hw->pg_state = MEI_PG_OFF;
        if (waitqueue_active(&dev->wait_pg))
                wake_up(&dev->wait_pg);
}

/**
 * mei_me_d0i3_intr - perform d0i3 processing in interrupt thread handler
 *
 * @dev: the device structure
 */
static void mei_me_d0i3_intr(struct mei_device *dev)
{
        struct mei_me_hw *hw = to_me_hw(dev);

        if (dev->pg_event == MEI_PG_EVENT_INTR_WAIT &&
            (hw->intr_source & H_D0I3C_IS)) {
                dev->pg_event = MEI_PG_EVENT_INTR_RECEIVED;
                if (hw->pg_state == MEI_PG_ON) {
                        hw->pg_state = MEI_PG_OFF;
                        if (dev->hbm_state != MEI_HBM_IDLE) {
                                /*
                                 * force H_RDY because it could be
                                 * wiped off during PG
                                 */
                                dev_dbg(dev->dev, "d0i3 set host ready\n");
                                mei_me_host_set_ready(dev);
                        }
                } else {
                        hw->pg_state = MEI_PG_ON;
                }

                wake_up(&dev->wait_pg);
        }

        if (hw->pg_state == MEI_PG_ON && (hw->intr_source & H_IS)) {
                /*
                 * HW sent some data and we are in D0i3, so
                 * we got here because of HW initiated exit from D0i3.
                 * Start runtime pm resume sequence to exit low power state.
                 */
                dev_dbg(dev->dev, "d0i3 want resume\n");
                mei_hbm_pg_resume(dev);
        }
}

/**
 * mei_me_pg_intr - perform pg processing in interrupt thread handler
 *
 * @dev: the device structure
 */
static void mei_me_pg_intr(struct mei_device *dev)

{
        struct mei_me_hw *hw = to_me_hw(dev);

        if (hw->d0i3_supported)
                mei_me_d0i3_intr(dev);
        else
                mei_me_pg_legacy_intr(dev);
}

/**
 * mei_me_pg_enter_sync - perform runtime pm entry procedure
 *
 * @dev: the device structure
 *
 * Return: 0 on success an error code otherwise
 */
int mei_me_pg_enter_sync(struct mei_device *dev)
{
        struct mei_me_hw *hw = to_me_hw(dev);

        if (hw->d0i3_supported)
                return mei_me_d0i3_enter_sync(dev);
        else
                return mei_me_pg_legacy_enter_sync(dev);
}

/**
 * mei_me_pg_exit_sync - perform runtime pm exit procedure
 *
 * @dev: the device structure
 *
 * Return: 0 on success an error code otherwise
 */
int mei_me_pg_exit_sync(struct mei_device *dev)
{
        struct mei_me_hw *hw = to_me_hw(dev);

        if (hw->d0i3_supported)
                return mei_me_d0i3_exit_sync(dev);
        else
                return mei_me_pg_legacy_exit_sync(dev);
}

/**
 * mei_me_hw_reset - resets fw via mei csr register.
 *
 * @dev: the device structure
 * @intr_enable: if interrupt should be enabled after reset.
 *
 * Return: 0 on success an error code otherwise
 */
static int mei_me_hw_reset(struct mei_device *dev, bool intr_enable)
{
        struct mei_me_hw *hw = to_me_hw(dev);
        int ret;
        u32 hcsr;

        if (intr_enable) {
                mei_me_intr_enable(dev);
                if (hw->d0i3_supported) {
                        ret = mei_me_d0i3_exit_sync(dev);
                        if (ret)
                                return ret;
                }
        }

        pm_runtime_set_active(dev->dev);

        hcsr = mei_hcsr_read(dev);
        /* H_RST may be found lit before reset is started,
         * for example if preceding reset flow hasn't completed.
         * In that case asserting H_RST will be ignored, therefore
         * we need to clean H_RST bit to start a successful reset sequence.
         */
        if ((hcsr & H_RST) == H_RST) {
                dev_warn(dev->dev, "H_RST is set = 0x%08X", hcsr);
                hcsr &= ~H_RST;
                mei_hcsr_set(dev, hcsr);
                hcsr = mei_hcsr_read(dev);
        }

        hcsr |= H_RST | H_IG | H_CSR_IS_MASK;

        if (!intr_enable)
                hcsr &= ~H_CSR_IE_MASK;

        dev->recvd_hw_ready = false;
        mei_hcsr_write(dev, hcsr);

        /*
         * Host reads the H_CSR once to ensure that the
         * posted write to H_CSR completes.
         */
        hcsr = mei_hcsr_read(dev);

        if ((hcsr & H_RST) == 0)
                dev_warn(dev->dev, "H_RST is not set = 0x%08X", hcsr);

        if ((hcsr & H_RDY) == H_RDY)
                dev_warn(dev->dev, "H_RDY is not cleared 0x%08X", hcsr);

        if (!intr_enable) {
                mei_me_hw_reset_release(dev);
                if (hw->d0i3_supported) {
                        ret = mei_me_d0i3_enter(dev);
                        if (ret)
                                return ret;
                }
        }

        return 0;
}


/**
 * mei_me_irq_quick_handler - The ISR of the MEI device
 *
 * @irq: The irq number
 * @dev_id: pointer to the device structure
 *
 * Return: irqreturn_t
 */
irqreturn_t mei_me_irq_quick_handler(int irq, void *dev_id)
{
        struct mei_device *dev = (struct mei_device *)dev_id;
        struct mei_me_hw *hw = to_me_hw(dev);
        u32 hcsr;

        hcsr = mei_hcsr_read(dev);
        if (!(hcsr & H_CSR_IS_MASK))
                return IRQ_NONE;

        hw->intr_source = hcsr & H_CSR_IS_MASK;
        dev_dbg(dev->dev, "interrupt source 0x%08X.\n", hw->intr_source);

        /* clear H_IS and H_D0I3C_IS bits in H_CSR to clear the interrupts */
        mei_hcsr_write(dev, hcsr);

        return IRQ_WAKE_THREAD;
}

/**
 * mei_me_irq_thread_handler - function called after ISR to handle the interrupt
 * processing.
 *
 * @irq: The irq number
 * @dev_id: pointer to the device structure
 *
 * Return: irqreturn_t
 *
 */
irqreturn_t mei_me_irq_thread_handler(int irq, void *dev_id)
{
        struct mei_device *dev = (struct mei_device *) dev_id;
        struct list_head cmpl_list;
        s32 slots;
        int rets = 0;

        dev_dbg(dev->dev, "function called after ISR to handle the interrupt processing.\n");
        /* initialize our complete list */
        mutex_lock(&dev->device_lock);
        INIT_LIST_HEAD(&cmpl_list);

        /* check if ME wants a reset */
        if (!mei_hw_is_ready(dev) && dev->dev_state != MEI_DEV_RESETTING) {
                dev_warn(dev->dev, "FW not ready: resetting.\n");
                schedule_work(&dev->reset_work);
                goto end;
        }

        mei_me_pg_intr(dev);

        /*  check if we need to start the dev */
        if (!mei_host_is_ready(dev)) {
                if (mei_hw_is_ready(dev)) {
                        dev_dbg(dev->dev, "we need to start the dev.\n");
                        dev->recvd_hw_ready = true;
                        wake_up(&dev->wait_hw_ready);
                } else {
                        dev_dbg(dev->dev, "Spurious Interrupt\n");
                }
                goto end;
        }
        /* check slots available for reading */
        slots = mei_count_full_read_slots(dev);
        while (slots > 0) {
                dev_dbg(dev->dev, "slots to read = %08x\n", slots);
                rets = mei_irq_read_handler(dev, &cmpl_list, &slots);
                /* There is a race between ME write and interrupt delivery:
                 * Not all data is always available immediately after the
                 * interrupt, so try to read again on the next interrupt.
                 */
                if (rets == -ENODATA)
                        break;

                if (rets && dev->dev_state != MEI_DEV_RESETTING) {
                        dev_err(dev->dev, "mei_irq_read_handler ret = %d.\n",
                                                rets);
                        schedule_work(&dev->reset_work);
                        goto end;
                }
        }

        dev->hbuf_is_ready = mei_hbuf_is_ready(dev);

        /*
         * During PG handshake only allowed write is the replay to the
         * PG exit message, so block calling write function
         * if the pg event is in PG handshake
         */
        if (dev->pg_event != MEI_PG_EVENT_WAIT &&
            dev->pg_event != MEI_PG_EVENT_RECEIVED) {
                rets = mei_irq_write_handler(dev, &cmpl_list);
                dev->hbuf_is_ready = mei_hbuf_is_ready(dev);
        }

        mei_irq_compl_handler(dev, &cmpl_list);

end:
        dev_dbg(dev->dev, "interrupt thread end ret = %d\n", rets);
        mutex_unlock(&dev->device_lock);
        return IRQ_HANDLED;
}

static const struct mei_hw_ops mei_me_hw_ops = {

        .fw_status = mei_me_fw_status,
        .pg_state  = mei_me_pg_state,

        .host_is_ready = mei_me_host_is_ready,

        .hw_is_ready = mei_me_hw_is_ready,
        .hw_reset = mei_me_hw_reset,
        .hw_config = mei_me_hw_config,
        .hw_start = mei_me_hw_start,

        .pg_in_transition = mei_me_pg_in_transition,
        .pg_is_enabled = mei_me_pg_is_enabled,

        .intr_clear = mei_me_intr_clear,
        .intr_enable = mei_me_intr_enable,
        .intr_disable = mei_me_intr_disable,

        .hbuf_free_slots = mei_me_hbuf_empty_slots,
        .hbuf_is_ready = mei_me_hbuf_is_empty,
        .hbuf_max_len = mei_me_hbuf_max_len,

        .write = mei_me_write_message,

        .rdbuf_full_slots = mei_me_count_full_read_slots,
        .read_hdr = mei_me_mecbrw_read,
        .read = mei_me_read_slots
};

static bool mei_me_fw_type_nm(struct pci_dev *pdev)
{
        u32 reg;

        pci_read_config_dword(pdev, PCI_CFG_HFS_2, &reg);
        trace_mei_pci_cfg_read(&pdev->dev, "PCI_CFG_HFS_2", PCI_CFG_HFS_2, reg);
        /* make sure that bit 9 (NM) is up and bit 10 (DM) is down */
        return (reg & 0x600) == 0x200;
}

#define MEI_CFG_FW_NM                           \
        .quirk_probe = mei_me_fw_type_nm

static bool mei_me_fw_type_sps(struct pci_dev *pdev)
{
        u32 reg;
        unsigned int devfn;

        /*
         * Read ME FW Status register to check for SPS Firmware
         * The SPS FW is only signaled in pci function 0
         */
        devfn = PCI_DEVFN(PCI_SLOT(pdev->devfn), 0);
        pci_bus_read_config_dword(pdev->bus, devfn, PCI_CFG_HFS_1, &reg);
        trace_mei_pci_cfg_read(&pdev->dev, "PCI_CFG_HFS_1", PCI_CFG_HFS_1, reg);
        /* if bits [19:16] = 15, running SPS Firmware */
        return (reg & 0xf0000) == 0xf0000;
}

#define MEI_CFG_FW_SPS                           \
        .quirk_probe = mei_me_fw_type_sps


#define MEI_CFG_LEGACY_HFS                      \
        .fw_status.count = 0

#define MEI_CFG_ICH_HFS                        \
        .fw_status.count = 1,                   \
        .fw_status.status[0] = PCI_CFG_HFS_1

#define MEI_CFG_PCH_HFS                         \
        .fw_status.count = 2,                   \
        .fw_status.status[0] = PCI_CFG_HFS_1,   \
        .fw_status.status[1] = PCI_CFG_HFS_2

#define MEI_CFG_PCH8_HFS                        \
        .fw_status.count = 6,                   \
        .fw_status.status[0] = PCI_CFG_HFS_1,   \
        .fw_status.status[1] = PCI_CFG_HFS_2,   \
        .fw_status.status[2] = PCI_CFG_HFS_3,   \
        .fw_status.status[3] = PCI_CFG_HFS_4,   \
        .fw_status.status[4] = PCI_CFG_HFS_5,   \
        .fw_status.status[5] = PCI_CFG_HFS_6

/* ICH Legacy devices */
const struct mei_cfg mei_me_legacy_cfg = {
        MEI_CFG_LEGACY_HFS,
};

/* ICH devices */
const struct mei_cfg mei_me_ich_cfg = {
        MEI_CFG_ICH_HFS,
};

/* PCH devices */
const struct mei_cfg mei_me_pch_cfg = {
        MEI_CFG_PCH_HFS,
};


/* PCH Cougar Point and Patsburg with quirk for Node Manager exclusion */
const struct mei_cfg mei_me_pch_cpt_pbg_cfg = {
        MEI_CFG_PCH_HFS,
        MEI_CFG_FW_NM,
};

/* PCH8 Lynx Point and newer devices */
const struct mei_cfg mei_me_pch8_cfg = {
        MEI_CFG_PCH8_HFS,
};

/* PCH8 Lynx Point with quirk for SPS Firmware exclusion */
const struct mei_cfg mei_me_pch8_sps_cfg = {
        MEI_CFG_PCH8_HFS,
        MEI_CFG_FW_SPS,
};

/**
 * mei_me_dev_init - allocates and initializes the mei device structure
 *
 * @pdev: The pci device structure
 * @cfg: per device generation config
 *
 * Return: The mei_device_device pointer on success, NULL on failure.
 */
struct mei_device *mei_me_dev_init(struct pci_dev *pdev,
                                   const struct mei_cfg *cfg)
{
        struct mei_device *dev;
        struct mei_me_hw *hw;

        dev = kzalloc(sizeof(struct mei_device) +
                         sizeof(struct mei_me_hw), GFP_KERNEL);
        if (!dev)
                return NULL;
        hw = to_me_hw(dev);

        mei_device_init(dev, &pdev->dev, &mei_me_hw_ops);
        hw->cfg = cfg;
        return dev;
}