// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2013-2022, Intel Corporation. All rights reserved.
 * Intel Management Engine Interface (Intel MEI) Linux driver
 */

#include <linux/pci.h>
#include <linux/jiffies.h>
#include <linux/ktime.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/interrupt.h>
#include <linux/pm_runtime.h>

#include <linux/mei.h>

#include "mei_dev.h"
#include "hw-txe.h"
#include "client.h"
#include "hbm.h"

#include "mei-trace.h"

#define TXE_HBUF_DEPTH (PAYLOAD_SIZE / MEI_SLOT_SIZE)

/**
 * mei_txe_reg_read - Reads 32bit data from the txe device
 *
 * @base_addr: registers base address
 * @offset: register offset
 *
 * Return: register value
 */
static inline u32 mei_txe_reg_read(void __iomem *base_addr,
                                        unsigned long offset)
{
        return ioread32(base_addr + offset);
}

/**
 * mei_txe_reg_write - Writes 32bit data to the txe device
 *
 * @base_addr: registers base address
 * @offset: register offset
 * @value: the value to write
 */
static inline void mei_txe_reg_write(void __iomem *base_addr,
                                unsigned long offset, u32 value)
{
        iowrite32(value, base_addr + offset);
}

/**
 * mei_txe_sec_reg_read_silent - Reads 32bit data from the SeC BAR
 *
 * @hw: the txe hardware structure
 * @offset: register offset
 *
 * Doesn't check for aliveness while Reads 32bit data from the SeC BAR
 *
 * Return: register value
 */
static inline u32 mei_txe_sec_reg_read_silent(struct mei_txe_hw *hw,
                                unsigned long offset)
{
        return mei_txe_reg_read(hw->mem_addr[SEC_BAR], offset);
}

/**
 * mei_txe_sec_reg_read - Reads 32bit data from the SeC BAR
 *
 * @hw: the txe hardware structure
 * @offset: register offset
 *
 * Reads 32bit data from the SeC BAR and shout loud if aliveness is not set
 *
 * Return: register value
 */
static inline u32 mei_txe_sec_reg_read(struct mei_txe_hw *hw,
                                unsigned long offset)
{
        WARN(!hw->aliveness, "sec read: aliveness not asserted\n");
        return mei_txe_sec_reg_read_silent(hw, offset);
}
/**
 * mei_txe_sec_reg_write_silent - Writes 32bit data to the SeC BAR
 *   doesn't check for aliveness
 *
 * @hw: the txe hardware structure
 * @offset: register offset
 * @value: value to write
 *
 * Doesn't check for aliveness while writes 32bit data from to the SeC BAR
 */
static inline void mei_txe_sec_reg_write_silent(struct mei_txe_hw *hw,
                                unsigned long offset, u32 value)
{
        mei_txe_reg_write(hw->mem_addr[SEC_BAR], offset, value);
}

/**
 * mei_txe_sec_reg_write - Writes 32bit data to the SeC BAR
 *
 * @hw: the txe hardware structure
 * @offset: register offset
 * @value: value to write
 *
 * Writes 32bit data from the SeC BAR and shout loud if aliveness is not set
 */
static inline void mei_txe_sec_reg_write(struct mei_txe_hw *hw,
                                unsigned long offset, u32 value)
{
        WARN(!hw->aliveness, "sec write: aliveness not asserted\n");
        mei_txe_sec_reg_write_silent(hw, offset, value);
}
/**
 * mei_txe_br_reg_read - Reads 32bit data from the Bridge BAR
 *
 * @hw: the txe hardware structure
 * @offset: offset from which to read the data
 *
 * Return: the byte read.
 */
static inline u32 mei_txe_br_reg_read(struct mei_txe_hw *hw,
                                unsigned long offset)
{
        return mei_txe_reg_read(hw->mem_addr[BRIDGE_BAR], offset);
}

/**
 * mei_txe_br_reg_write - Writes 32bit data to the Bridge BAR
 *
 * @hw: the txe hardware structure
 * @offset: offset from which to write the data
 * @value: the byte to write
 */
static inline void mei_txe_br_reg_write(struct mei_txe_hw *hw,
                                unsigned long offset, u32 value)
{
        mei_txe_reg_write(hw->mem_addr[BRIDGE_BAR], offset, value);
}

/**
 * mei_txe_aliveness_set - request for aliveness change
 *
 * @dev: the device structure
 * @req: requested aliveness value
 *
 * Request for aliveness change and returns true if the change is
 *   really needed and false if aliveness is already
 *   in the requested state
 *
 * Locking: called under "dev->device_lock" lock
 *
 * Return: true if request was send
 */
static bool mei_txe_aliveness_set(struct mei_device *dev, u32 req)
{

        struct mei_txe_hw *hw = to_txe_hw(dev);
        bool do_req = hw->aliveness != req;

        dev_dbg(&dev->dev, "Aliveness current=%d request=%d\n",
                                hw->aliveness, req);
        if (do_req) {
                dev->pg_event = MEI_PG_EVENT_WAIT;
                mei_txe_br_reg_write(hw, SICR_HOST_ALIVENESS_REQ_REG, req);
        }
        return do_req;
}


/**
 * mei_txe_aliveness_req_get - get aliveness requested register value
 *
 * @dev: the device structure
 *
 * Extract HICR_HOST_ALIVENESS_RESP_ACK bit from
 * HICR_HOST_ALIVENESS_REQ register value
 *
 * Return: SICR_HOST_ALIVENESS_REQ_REQUESTED bit value
 */
static u32 mei_txe_aliveness_req_get(struct mei_device *dev)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);
        u32 reg;

        reg = mei_txe_br_reg_read(hw, SICR_HOST_ALIVENESS_REQ_REG);
        return reg & SICR_HOST_ALIVENESS_REQ_REQUESTED;
}

/**
 * mei_txe_aliveness_get - get aliveness response register value
 *
 * @dev: the device structure
 *
 * Return: HICR_HOST_ALIVENESS_RESP_ACK bit from HICR_HOST_ALIVENESS_RESP
 *         register
 */
static u32 mei_txe_aliveness_get(struct mei_device *dev)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);
        u32 reg;

        reg = mei_txe_br_reg_read(hw, HICR_HOST_ALIVENESS_RESP_REG);
        return reg & HICR_HOST_ALIVENESS_RESP_ACK;
}

/**
 * mei_txe_aliveness_poll - waits for aliveness to settle
 *
 * @dev: the device structure
 * @expected: expected aliveness value
 *
 * Polls for HICR_HOST_ALIVENESS_RESP.ALIVENESS_RESP to be set
 *
 * Return: 0 if the expected value was received, -ETIME otherwise
 */
static int mei_txe_aliveness_poll(struct mei_device *dev, u32 expected)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);
        ktime_t stop, start;

        start = ktime_get();
        stop = ktime_add(start, ms_to_ktime(SEC_ALIVENESS_WAIT_TIMEOUT));
        do {
                hw->aliveness = mei_txe_aliveness_get(dev);
                if (hw->aliveness == expected) {
                        dev->pg_event = MEI_PG_EVENT_IDLE;
                        dev_dbg(&dev->dev, "aliveness settled after %lld usecs\n",
                                ktime_to_us(ktime_sub(ktime_get(), start)));
                        return 0;
                }
                usleep_range(20, 50);
        } while (ktime_before(ktime_get(), stop));

        dev->pg_event = MEI_PG_EVENT_IDLE;
        dev_err(&dev->dev, "aliveness timed out\n");
        return -ETIME;
}

/**
 * mei_txe_aliveness_wait - waits for aliveness to settle
 *
 * @dev: the device structure
 * @expected: expected aliveness value
 *
 * Waits for HICR_HOST_ALIVENESS_RESP.ALIVENESS_RESP to be set
 *
 * Return: 0 on success and < 0 otherwise
 */
static int mei_txe_aliveness_wait(struct mei_device *dev, u32 expected)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);
        const unsigned long timeout =
                        msecs_to_jiffies(SEC_ALIVENESS_WAIT_TIMEOUT);
        long err;
        int ret;

        hw->aliveness = mei_txe_aliveness_get(dev);
        if (hw->aliveness == expected)
                return 0;

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

        hw->aliveness = mei_txe_aliveness_get(dev);
        ret = hw->aliveness == expected ? 0 : -ETIME;

        if (ret)
                dev_warn(&dev->dev, "aliveness timed out = %ld aliveness = %d event = %d\n",
                        err, hw->aliveness, dev->pg_event);
        else
                dev_dbg(&dev->dev, "aliveness settled after = %d msec aliveness = %d event = %d\n",
                        jiffies_to_msecs(timeout - err),
                        hw->aliveness, dev->pg_event);

        dev->pg_event = MEI_PG_EVENT_IDLE;
        return ret;
}

/**
 * mei_txe_aliveness_set_sync - sets an wait for aliveness to complete
 *
 * @dev: the device structure
 * @req: requested aliveness value
 *
 * Return: 0 on success and < 0 otherwise
 */
int mei_txe_aliveness_set_sync(struct mei_device *dev, u32 req)
{
        if (mei_txe_aliveness_set(dev, req))
                return mei_txe_aliveness_wait(dev, req);
        return 0;
}

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

/**
 * mei_txe_pg_is_enabled - detect if PG is supported by HW
 *
 * @dev: the device structure
 *
 * Return: true is pg supported, false otherwise
 */
static bool mei_txe_pg_is_enabled(struct mei_device *dev)
{
        return true;
}

/**
 * mei_txe_pg_state  - translate aliveness register value
 *   to the mei power gating state
 *
 * @dev: the device structure
 *
 * Return: MEI_PG_OFF if aliveness is on and MEI_PG_ON otherwise
 */
static inline enum mei_pg_state mei_txe_pg_state(struct mei_device *dev)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);

        return hw->aliveness ? MEI_PG_OFF : MEI_PG_ON;
}

/**
 * mei_txe_input_ready_interrupt_enable - sets the Input Ready Interrupt
 *
 * @dev: the device structure
 */
static void mei_txe_input_ready_interrupt_enable(struct mei_device *dev)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);
        u32 hintmsk;
        /* Enable the SEC_IPC_HOST_INT_MASK_IN_RDY interrupt */
        hintmsk = mei_txe_sec_reg_read(hw, SEC_IPC_HOST_INT_MASK_REG);
        hintmsk |= SEC_IPC_HOST_INT_MASK_IN_RDY;
        mei_txe_sec_reg_write(hw, SEC_IPC_HOST_INT_MASK_REG, hintmsk);
}

/**
 * mei_txe_input_doorbell_set - sets bit 0 in
 *    SEC_IPC_INPUT_DOORBELL.IPC_INPUT_DOORBELL.
 *
 * @hw: the txe hardware structure
 */
static void mei_txe_input_doorbell_set(struct mei_txe_hw *hw)
{
        /* Clear the interrupt cause */
        clear_bit(TXE_INTR_IN_READY_BIT, &hw->intr_cause);
        mei_txe_sec_reg_write(hw, SEC_IPC_INPUT_DOORBELL_REG, 1);
}

/**
 * mei_txe_output_ready_set - Sets the SICR_SEC_IPC_OUTPUT_STATUS bit to 1
 *
 * @hw: the txe hardware structure
 */
static void mei_txe_output_ready_set(struct mei_txe_hw *hw)
{
        mei_txe_br_reg_write(hw,
                        SICR_SEC_IPC_OUTPUT_STATUS_REG,
                        SEC_IPC_OUTPUT_STATUS_RDY);
}

/**
 * mei_txe_is_input_ready - check if TXE is ready for receiving data
 *
 * @dev: the device structure
 *
 * Return: true if INPUT STATUS READY bit is set
 */
static bool mei_txe_is_input_ready(struct mei_device *dev)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);
        u32 status;

        status = mei_txe_sec_reg_read(hw, SEC_IPC_INPUT_STATUS_REG);
        return !!(SEC_IPC_INPUT_STATUS_RDY & status);
}

/**
 * mei_txe_intr_clear - clear all interrupts
 *
 * @dev: the device structure
 */
static inline void mei_txe_intr_clear(struct mei_device *dev)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);

        mei_txe_sec_reg_write_silent(hw, SEC_IPC_HOST_INT_STATUS_REG,
                SEC_IPC_HOST_INT_STATUS_PENDING);
        mei_txe_br_reg_write(hw, HISR_REG, HISR_INT_STS_MSK);
        mei_txe_br_reg_write(hw, HHISR_REG, IPC_HHIER_MSK);
}

/**
 * mei_txe_intr_disable - disable all interrupts
 *
 * @dev: the device structure
 */
static void mei_txe_intr_disable(struct mei_device *dev)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);

        mei_txe_br_reg_write(hw, HHIER_REG, 0);
        mei_txe_br_reg_write(hw, HIER_REG, 0);
}
/**
 * mei_txe_intr_enable - enable all interrupts
 *
 * @dev: the device structure
 */
static void mei_txe_intr_enable(struct mei_device *dev)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);

        mei_txe_br_reg_write(hw, HHIER_REG, IPC_HHIER_MSK);
        mei_txe_br_reg_write(hw, HIER_REG, HIER_INT_EN_MSK);
}

/**
 * mei_txe_synchronize_irq - wait for pending IRQ handlers
 *
 * @dev: the device structure
 */
static void mei_txe_synchronize_irq(struct mei_device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev->parent);

        synchronize_irq(pdev->irq);
}

/**
 * mei_txe_pending_interrupts - check if there are pending interrupts
 *      only Aliveness, Input ready, and output doorbell are of relevance
 *
 * @dev: the device structure
 *
 * Checks if there are pending interrupts
 * only Aliveness, Readiness, Input ready, and Output doorbell are relevant
 *
 * Return: true if there are pending interrupts
 */
static bool mei_txe_pending_interrupts(struct mei_device *dev)
{

        struct mei_txe_hw *hw = to_txe_hw(dev);
        bool ret = (hw->intr_cause & (TXE_INTR_READINESS |
                                      TXE_INTR_ALIVENESS |
                                      TXE_INTR_IN_READY  |
                                      TXE_INTR_OUT_DB));

        if (ret) {
                dev_dbg(&dev->dev,
                        "Pending Interrupts InReady=%01d Readiness=%01d, Aliveness=%01d, OutDoor=%01d\n",
                        !!(hw->intr_cause & TXE_INTR_IN_READY),
                        !!(hw->intr_cause & TXE_INTR_READINESS),
                        !!(hw->intr_cause & TXE_INTR_ALIVENESS),
                        !!(hw->intr_cause & TXE_INTR_OUT_DB));
        }
        return ret;
}

/**
 * mei_txe_input_payload_write - write a dword to the host buffer
 *      at offset idx
 *
 * @dev: the device structure
 * @idx: index in the host buffer
 * @value: value
 */
static void mei_txe_input_payload_write(struct mei_device *dev,
                        unsigned long idx, u32 value)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);

        mei_txe_sec_reg_write(hw, SEC_IPC_INPUT_PAYLOAD_REG +
                        (idx * sizeof(u32)), value);
}

/**
 * mei_txe_out_data_read - read dword from the device buffer
 *      at offset idx
 *
 * @dev: the device structure
 * @idx: index in the device buffer
 *
 * Return: register value at index
 */
static u32 mei_txe_out_data_read(const struct mei_device *dev,
                                        unsigned long idx)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);

        return mei_txe_br_reg_read(hw,
                BRIDGE_IPC_OUTPUT_PAYLOAD_REG + (idx * sizeof(u32)));
}

/* Readiness */

/**
 * mei_txe_readiness_set_host_rdy - set host readiness bit
 *
 * @dev: the device structure
 */
static void mei_txe_readiness_set_host_rdy(struct mei_device *dev)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);

        mei_txe_br_reg_write(hw,
                SICR_HOST_IPC_READINESS_REQ_REG,
                SICR_HOST_IPC_READINESS_HOST_RDY);
}

/**
 * mei_txe_readiness_clear - clear host readiness bit
 *
 * @dev: the device structure
 */
static void mei_txe_readiness_clear(struct mei_device *dev)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);

        mei_txe_br_reg_write(hw, SICR_HOST_IPC_READINESS_REQ_REG,
                                SICR_HOST_IPC_READINESS_RDY_CLR);
}
/**
 * mei_txe_readiness_get - Reads and returns
 *      the HICR_SEC_IPC_READINESS register value
 *
 * @dev: the device structure
 *
 * Return: the HICR_SEC_IPC_READINESS register value
 */
static u32 mei_txe_readiness_get(struct mei_device *dev)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);

        return mei_txe_br_reg_read(hw, HICR_SEC_IPC_READINESS_REG);
}


/**
 * mei_txe_readiness_is_sec_rdy - check readiness
 *  for HICR_SEC_IPC_READINESS_SEC_RDY
 *
 * @readiness: cached readiness state
 *
 * Return: true if readiness bit is set
 */
static inline bool mei_txe_readiness_is_sec_rdy(u32 readiness)
{
        return !!(readiness & HICR_SEC_IPC_READINESS_SEC_RDY);
}

/**
 * mei_txe_hw_is_ready - check if the hw is ready
 *
 * @dev: the device structure
 *
 * Return: true if sec is ready
 */
static bool mei_txe_hw_is_ready(struct mei_device *dev)
{
        u32 readiness =  mei_txe_readiness_get(dev);

        return mei_txe_readiness_is_sec_rdy(readiness);
}

/**
 * mei_txe_host_is_ready - check if the host is ready
 *
 * @dev: the device structure
 *
 * Return: true if host is ready
 */
static inline bool mei_txe_host_is_ready(struct mei_device *dev)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);
        u32 reg = mei_txe_br_reg_read(hw, HICR_SEC_IPC_READINESS_REG);

        return !!(reg & HICR_SEC_IPC_READINESS_HOST_RDY);
}

/**
 * mei_txe_readiness_wait - wait till readiness settles
 *
 * @dev: the device structure
 *
 * Return: 0 on success and -ETIME on timeout
 */
static int mei_txe_readiness_wait(struct mei_device *dev)
{
        if (mei_txe_hw_is_ready(dev))
                return 0;

        mutex_unlock(&dev->device_lock);
        wait_event_timeout(dev->wait_hw_ready, dev->recvd_hw_ready,
                        msecs_to_jiffies(SEC_RESET_WAIT_TIMEOUT));
        mutex_lock(&dev->device_lock);
        if (!dev->recvd_hw_ready) {
                dev_err(&dev->dev, "wait for readiness failed\n");
                return -ETIME;
        }

        dev->recvd_hw_ready = false;
        return 0;
}

static const struct mei_fw_status mei_txe_fw_sts = {
        .count = 2,
        .status[0] = PCI_CFG_TXE_FW_STS0,
        .status[1] = PCI_CFG_TXE_FW_STS1
};

/**
 * mei_txe_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_txe_fw_status(struct mei_device *dev,
                             struct mei_fw_status *fw_status)
{
        const struct mei_fw_status *fw_src = &mei_txe_fw_sts;
        struct pci_dev *pdev = to_pci_dev(dev->parent);
        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_txe_hw_config - configure hardware at the start of the devices
 *
 * @dev: the device structure
 *
 * Configure hardware at the start of the device should be done only
 *   once at the device probe time
 *
 * Return: always 0
 */
static int mei_txe_hw_config(struct mei_device *dev)
{

        struct mei_txe_hw *hw = to_txe_hw(dev);

        hw->aliveness = mei_txe_aliveness_get(dev);
        hw->readiness = mei_txe_readiness_get(dev);

        dev_dbg(&dev->dev, "aliveness_resp = 0x%08x, readiness = 0x%08x.\n",
                hw->aliveness, hw->readiness);

        return 0;
}

/**
 * mei_txe_write - writes a message to device.
 *
 * @dev: the device structure
 * @hdr: header of message
 * @hdr_len: header length in bytes - must multiplication of a slot (4bytes)
 * @data: payload
 * @data_len: paylead length in bytes
 *
 * Return: 0 if success, < 0 - otherwise.
 */
static int mei_txe_write(struct mei_device *dev,
                         const void *hdr, size_t hdr_len,
                         const void *data, size_t data_len)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);
        unsigned long rem;
        const u32 *reg_buf;
        u32 slots = TXE_HBUF_DEPTH;
        u32 dw_cnt;
        unsigned long i, j;

        if (WARN_ON(!hdr || !data || hdr_len & 0x3))
                return -EINVAL;

        dev_dbg(&dev->dev, MEI_HDR_FMT, MEI_HDR_PRM((struct mei_msg_hdr *)hdr));

        dw_cnt = mei_data2slots(hdr_len + data_len);
        if (dw_cnt > slots)
                return -EMSGSIZE;

        if (WARN(!hw->aliveness, "txe write: aliveness not asserted\n"))
                return -EAGAIN;

        /* Enable Input Ready Interrupt. */
        mei_txe_input_ready_interrupt_enable(dev);

        if (!mei_txe_is_input_ready(dev)) {
                char fw_sts_str[MEI_FW_STATUS_STR_SZ];

                mei_fw_status_str(dev, fw_sts_str, MEI_FW_STATUS_STR_SZ);
                dev_err(&dev->dev, "Input is not ready %s\n", fw_sts_str);
                return -EAGAIN;
        }

        reg_buf = hdr;
        for (i = 0; i < hdr_len / MEI_SLOT_SIZE; i++)
                mei_txe_input_payload_write(dev, i, reg_buf[i]);

        reg_buf = data;
        for (j = 0; j < data_len / MEI_SLOT_SIZE; j++)
                mei_txe_input_payload_write(dev, i + j, reg_buf[j]);

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

                memcpy(&reg, (const u8 *)data + data_len - rem, rem);
                mei_txe_input_payload_write(dev, i + j, reg);
        }

        /* after each write the whole buffer is consumed */
        hw->slots = 0;

        /* Set Input-Doorbell */
        mei_txe_input_doorbell_set(hw);

        return 0;
}

/**
 * mei_txe_hbuf_depth - mimics the me hbuf circular buffer
 *
 * @dev: the device structure
 *
 * Return: the TXE_HBUF_DEPTH
 */
static u32 mei_txe_hbuf_depth(const struct mei_device *dev)
{
        return TXE_HBUF_DEPTH;
}

/**
 * mei_txe_hbuf_empty_slots - mimics the me hbuf circular buffer
 *
 * @dev: the device structure
 *
 * Return: always TXE_HBUF_DEPTH
 */
static int mei_txe_hbuf_empty_slots(struct mei_device *dev)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);

        return hw->slots;
}

/**
 * mei_txe_count_full_read_slots - mimics the me device circular buffer
 *
 * @dev: the device structure
 *
 * Return: always buffer size in dwords count
 */
static int mei_txe_count_full_read_slots(struct mei_device *dev)
{
        /* read buffers has static size */
        return TXE_HBUF_DEPTH;
}

/**
 * mei_txe_read_hdr - read message header which is always in 4 first bytes
 *
 * @dev: the device structure
 *
 * Return: mei message header
 */

static u32 mei_txe_read_hdr(const struct mei_device *dev)
{
        return mei_txe_out_data_read(dev, 0);
}
/**
 * mei_txe_read - reads a message from the txe device.
 *
 * @dev: the device structure
 * @buf: message buffer will be written
 * @len: message size will be read
 *
 * Return: -EINVAL on error wrong argument and 0 on success
 */
static int mei_txe_read(struct mei_device *dev,
                unsigned char *buf, unsigned long len)
{

        struct mei_txe_hw *hw = to_txe_hw(dev);
        u32 *reg_buf, reg;
        u32 rem;
        u32 i;

        if (WARN_ON(!buf || !len))
                return -EINVAL;

        reg_buf = (u32 *)buf;
        rem = len & 0x3;

        dev_dbg(&dev->dev, "buffer-length = %lu buf[0]0x%08X\n",
                len, mei_txe_out_data_read(dev, 0));

        for (i = 0; i < len / MEI_SLOT_SIZE; i++) {
                /* skip header: index starts from 1 */
                reg = mei_txe_out_data_read(dev, i + 1);
                dev_dbg(&dev->dev, "buf[%d] = 0x%08X\n", i, reg);
                *reg_buf++ = reg;
        }

        if (rem) {
                reg = mei_txe_out_data_read(dev, i + 1);
                memcpy(reg_buf, &reg, rem);
        }

        mei_txe_output_ready_set(hw);
        return 0;
}

/**
 * mei_txe_hw_reset - resets host and fw.
 *
 * @dev: the device structure
 * @intr_enable: if interrupt should be enabled after reset.
 *
 * Return: 0 on success and < 0 in case of error
 */
static int mei_txe_hw_reset(struct mei_device *dev, bool intr_enable)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);

        u32 aliveness_req;
        /*
         * read input doorbell to ensure consistency between  Bridge and SeC
         * return value might be garbage return
         */
        (void)mei_txe_sec_reg_read_silent(hw, SEC_IPC_INPUT_DOORBELL_REG);

        aliveness_req = mei_txe_aliveness_req_get(dev);
        hw->aliveness = mei_txe_aliveness_get(dev);

        /* Disable interrupts in this stage we will poll */
        mei_txe_intr_disable(dev);

        /*
         * If Aliveness Request and Aliveness Response are not equal then
         * wait for them to be equal
         * Since we might have interrupts disabled - poll for it
         */
        if (aliveness_req != hw->aliveness)
                if (mei_txe_aliveness_poll(dev, aliveness_req) < 0) {
                        dev_err(&dev->dev, "wait for aliveness settle failed ... bailing out\n");
                        return -EIO;
                }

        /*
         * If Aliveness Request and Aliveness Response are set then clear them
         */
        if (aliveness_req) {
                mei_txe_aliveness_set(dev, 0);
                if (mei_txe_aliveness_poll(dev, 0) < 0) {
                        dev_err(&dev->dev, "wait for aliveness failed ... bailing out\n");
                        return -EIO;
                }
        }

        /*
         * Set readiness RDY_CLR bit
         */
        mei_txe_readiness_clear(dev);

        return 0;
}

/**
 * mei_txe_hw_start - start the hardware after reset
 *
 * @dev: the device structure
 *
 * Return: 0 on success an error code otherwise
 */
static int mei_txe_hw_start(struct mei_device *dev)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);
        int ret;

        u32 hisr;

        /* bring back interrupts */
        mei_txe_intr_enable(dev);

        ret = mei_txe_readiness_wait(dev);
        if (ret < 0) {
                dev_err(&dev->dev, "waiting for readiness failed\n");
                return ret;
        }

        /*
         * If HISR.INT2_STS interrupt status bit is set then clear it.
         */
        hisr = mei_txe_br_reg_read(hw, HISR_REG);
        if (hisr & HISR_INT_2_STS)
                mei_txe_br_reg_write(hw, HISR_REG, HISR_INT_2_STS);

        /* Clear the interrupt cause of OutputDoorbell */
        clear_bit(TXE_INTR_OUT_DB_BIT, &hw->intr_cause);

        ret = mei_txe_aliveness_set_sync(dev, 1);
        if (ret < 0) {
                dev_err(&dev->dev, "wait for aliveness failed ... bailing out\n");
                return ret;
        }

        pm_runtime_set_active(dev->parent);

        /* enable input ready interrupts:
         * SEC_IPC_HOST_INT_MASK.IPC_INPUT_READY_INT_MASK
         */
        mei_txe_input_ready_interrupt_enable(dev);


        /*  Set the SICR_SEC_IPC_OUTPUT_STATUS.IPC_OUTPUT_READY bit */
        mei_txe_output_ready_set(hw);

        /* Set bit SICR_HOST_IPC_READINESS.HOST_RDY
         */
        mei_txe_readiness_set_host_rdy(dev);

        return 0;
}

/**
 * mei_txe_check_and_ack_intrs - translate multi BAR interrupt into
 *  single bit mask and acknowledge the interrupts
 *
 * @dev: the device structure
 * @do_ack: acknowledge interrupts
 *
 * Return: true if found interrupts to process.
 */
static bool mei_txe_check_and_ack_intrs(struct mei_device *dev, bool do_ack)
{
        struct mei_txe_hw *hw = to_txe_hw(dev);
        u32 hisr;
        u32 hhisr;
        u32 ipc_isr;
        u32 aliveness;
        bool generated;

        /* read interrupt registers */
        hhisr = mei_txe_br_reg_read(hw, HHISR_REG);
        generated = (hhisr & IPC_HHIER_MSK);
        if (!generated)
                goto out;

        hisr = mei_txe_br_reg_read(hw, HISR_REG);

        aliveness = mei_txe_aliveness_get(dev);
        if (hhisr & IPC_HHIER_SEC && aliveness) {
                ipc_isr = mei_txe_sec_reg_read_silent(hw,
                                SEC_IPC_HOST_INT_STATUS_REG);
        } else {
                ipc_isr = 0;
                hhisr &= ~IPC_HHIER_SEC;
        }

        if (do_ack) {
                /* Save the interrupt causes */
                hw->intr_cause |= hisr & HISR_INT_STS_MSK;
                if (ipc_isr & SEC_IPC_HOST_INT_STATUS_IN_RDY)
                        hw->intr_cause |= TXE_INTR_IN_READY;


                mei_txe_intr_disable(dev);
                /* Clear the interrupts in hierarchy:
                 * IPC and Bridge, than the High Level */
                mei_txe_sec_reg_write_silent(hw,
                        SEC_IPC_HOST_INT_STATUS_REG, ipc_isr);
                mei_txe_br_reg_write(hw, HISR_REG, hisr);
                mei_txe_br_reg_write(hw, HHISR_REG, hhisr);
        }

out:
        return generated;
}

/**
 * mei_txe_irq_quick_handler - The ISR of the MEI device
 *
 * @irq: The irq number
 * @dev_id: pointer to the device structure
 *
 * Return: IRQ_WAKE_THREAD if interrupt is designed for the device
 *         IRQ_NONE otherwise
 */
irqreturn_t mei_txe_irq_quick_handler(int irq, void *dev_id)
{
        struct mei_device *dev = dev_id;

        if (mei_txe_check_and_ack_intrs(dev, true))
                return IRQ_WAKE_THREAD;
        return IRQ_NONE;
}


/**
 * mei_txe_irq_thread_handler - txe interrupt thread
 *
 * @irq: The irq number
 * @dev_id: pointer to the device structure
 *
 * Return: IRQ_HANDLED
 */
irqreturn_t mei_txe_irq_thread_handler(int irq, void *dev_id)
{
        struct mei_device *dev = (struct mei_device *) dev_id;
        struct mei_txe_hw *hw = to_txe_hw(dev);
        struct list_head cmpl_list;
        s32 slots;
        int rets = 0;

        dev_dbg(&dev->dev, "irq thread: Interrupt Registers HHISR|HISR|SEC=%02X|%04X|%02X\n",
                mei_txe_br_reg_read(hw, HHISR_REG),
                mei_txe_br_reg_read(hw, HISR_REG),
                mei_txe_sec_reg_read_silent(hw, SEC_IPC_HOST_INT_STATUS_REG));


        /* initialize our complete list */
        mutex_lock(&dev->device_lock);
        INIT_LIST_HEAD(&cmpl_list);

        if (pci_dev_msi_enabled(to_pci_dev(dev->parent)))
                mei_txe_check_and_ack_intrs(dev, true);

        /* show irq events */
        mei_txe_pending_interrupts(dev);

        hw->aliveness = mei_txe_aliveness_get(dev);
        hw->readiness = mei_txe_readiness_get(dev);

        /* Readiness:
         * Detection of TXE driver going through reset
         * or TXE driver resetting the HECI interface.
         */
        if (test_and_clear_bit(TXE_INTR_READINESS_BIT, &hw->intr_cause)) {
                dev_dbg(&dev->dev, "Readiness Interrupt was received...\n");

                /* Check if SeC is going through reset */
                if (mei_txe_readiness_is_sec_rdy(hw->readiness)) {
                        dev_dbg(&dev->dev, "we need to start the dev.\n");
                        dev->recvd_hw_ready = true;
                } else {
                        dev->recvd_hw_ready = false;
                        if (dev->dev_state != MEI_DEV_RESETTING) {

                                dev_warn(&dev->dev, "FW not ready: resetting.\n");
                                schedule_work(&dev->reset_work);
                                goto end;

                        }
                }
                wake_up(&dev->wait_hw_ready);
        }

        /************************************************************/
        /* Check interrupt cause:
         * Aliveness: Detection of SeC acknowledge of host request that
         * it remain alive or host cancellation of that request.
         */

        if (test_and_clear_bit(TXE_INTR_ALIVENESS_BIT, &hw->intr_cause)) {
                /* Clear the interrupt cause */
                dev_dbg(&dev->dev,
                        "Aliveness Interrupt: Status: %d\n", hw->aliveness);
                dev->pg_event = MEI_PG_EVENT_RECEIVED;
                if (waitqueue_active(&hw->wait_aliveness_resp))
                        wake_up(&hw->wait_aliveness_resp);
        }


        /* Output Doorbell:
         * Detection of SeC having sent output to host
         */
        slots = mei_count_full_read_slots(dev);
        if (test_and_clear_bit(TXE_INTR_OUT_DB_BIT, &hw->intr_cause)) {
                /* Read from TXE */
                rets = mei_irq_read_handler(dev, &cmpl_list, &slots);
                if (rets &&
                    (dev->dev_state != MEI_DEV_RESETTING &&
                     dev->dev_state != MEI_DEV_POWER_DOWN)) {
                        dev_err(&dev->dev,
                                "mei_irq_read_handler ret = %d.\n", rets);

                        schedule_work(&dev->reset_work);
                        goto end;
                }
        }
        /* Input Ready: Detection if host can write to SeC */
        if (test_and_clear_bit(TXE_INTR_IN_READY_BIT, &hw->intr_cause)) {
                dev->hbuf_is_ready = true;
                hw->slots = TXE_HBUF_DEPTH;
        }

        if (hw->aliveness && dev->hbuf_is_ready) {
                /* get the real register value */
                dev->hbuf_is_ready = mei_hbuf_is_ready(dev);
                rets = mei_irq_write_handler(dev, &cmpl_list);
                if (rets && rets != -EMSGSIZE)
                        dev_err(&dev->dev, "mei_irq_write_handler ret = %d.\n",
                                rets);
                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);

        mei_enable_interrupts(dev);
        return IRQ_HANDLED;
}

static const struct mei_hw_ops mei_txe_hw_ops = {

        .host_is_ready = mei_txe_host_is_ready,

        .fw_status = mei_txe_fw_status,
        .pg_state = mei_txe_pg_state,

        .hw_is_ready = mei_txe_hw_is_ready,
        .hw_reset = mei_txe_hw_reset,
        .hw_config = mei_txe_hw_config,
        .hw_start = mei_txe_hw_start,

        .pg_in_transition = mei_txe_pg_in_transition,
        .pg_is_enabled = mei_txe_pg_is_enabled,

        .intr_clear = mei_txe_intr_clear,
        .intr_enable = mei_txe_intr_enable,
        .intr_disable = mei_txe_intr_disable,
        .synchronize_irq = mei_txe_synchronize_irq,

        .hbuf_free_slots = mei_txe_hbuf_empty_slots,
        .hbuf_is_ready = mei_txe_is_input_ready,
        .hbuf_depth = mei_txe_hbuf_depth,

        .write = mei_txe_write,

        .rdbuf_full_slots = mei_txe_count_full_read_slots,
        .read_hdr = mei_txe_read_hdr,

        .read = mei_txe_read,

};

/**
 * mei_txe_dev_init - allocates and initializes txe hardware specific structure
 *
 * @pdev: pci device
 *
 * Return: struct mei_device * on success or NULL
 */
struct mei_device *mei_txe_dev_init(struct pci_dev *pdev)
{
        struct mei_device *dev;
        struct mei_txe_hw *hw;

        dev = kzalloc(sizeof(*dev) + sizeof(*hw), GFP_KERNEL);
        if (!dev)
                return NULL;

        mei_device_init(dev, &pdev->dev, false, &mei_txe_hw_ops);

        hw = to_txe_hw(dev);

        init_waitqueue_head(&hw->wait_aliveness_resp);

        return dev;
}