// SPDX-License-Identifier: (BSD-3-Clause OR GPL-2.0-only)
/* Copyright(c) 2015 - 2021 Intel Corporation */
#include <linux/bitfield.h>
#include <linux/completion.h>
#include <linux/minmax.h>
#include <linux/types.h>
#include "adf_accel_devices.h"
#include "adf_common_drv.h"
#include "adf_pfvf_msg.h"
#include "adf_pfvf_utils.h"
#include "adf_pfvf_vf_msg.h"
#include "adf_pfvf_vf_proto.h"

#define ADF_PFVF_MSG_COLLISION_DETECT_DELAY     10
#define ADF_PFVF_MSG_ACK_DELAY                  2
#define ADF_PFVF_MSG_ACK_MAX_RETRY              100

/* How often to retry if there is no response */
#define ADF_PFVF_MSG_RESP_RETRIES       5
#define ADF_PFVF_MSG_RESP_TIMEOUT       (ADF_PFVF_MSG_ACK_DELAY * \
                                         ADF_PFVF_MSG_ACK_MAX_RETRY + \
                                         ADF_PFVF_MSG_COLLISION_DETECT_DELAY)

/**
 * adf_send_vf2pf_msg() - send VF to PF message
 * @accel_dev:  Pointer to acceleration device
 * @msg:        Message to send
 *
 * This function allows the VF to send a message to the PF.
 *
 * Return: 0 on success, error code otherwise.
 */
int adf_send_vf2pf_msg(struct adf_accel_dev *accel_dev, struct pfvf_message msg)
{
        struct adf_pfvf_ops *pfvf_ops = GET_PFVF_OPS(accel_dev);
        u32 pfvf_offset = pfvf_ops->get_vf2pf_offset(0);

        return pfvf_ops->send_msg(accel_dev, msg, pfvf_offset,
                                  &accel_dev->vf.vf2pf_lock);
}

/**
 * adf_recv_pf2vf_msg() - receive a PF to VF message
 * @accel_dev:  Pointer to acceleration device
 *
 * This function allows the VF to receive a message from the PF.
 *
 * Return: a valid message on success, zero otherwise.
 */
static struct pfvf_message adf_recv_pf2vf_msg(struct adf_accel_dev *accel_dev)
{
        struct adf_pfvf_ops *pfvf_ops = GET_PFVF_OPS(accel_dev);
        u32 pfvf_offset = pfvf_ops->get_pf2vf_offset(0);

        return pfvf_ops->recv_msg(accel_dev, pfvf_offset, accel_dev->vf.pf_compat_ver);
}

/**
 * adf_send_vf2pf_req() - send VF2PF request message
 * @accel_dev:  Pointer to acceleration device.
 * @msg:        Request message to send
 * @resp:       Returned PF response
 *
 * This function sends a message that requires a response from the VF to the PF
 * and waits for a reply.
 *
 * Return: 0 on success, error code otherwise.
 */
int adf_send_vf2pf_req(struct adf_accel_dev *accel_dev, struct pfvf_message msg,
                       struct pfvf_message *resp)
{
        unsigned long timeout = msecs_to_jiffies(ADF_PFVF_MSG_RESP_TIMEOUT);
        unsigned int retries = ADF_PFVF_MSG_RESP_RETRIES;
        int ret;

        reinit_completion(&accel_dev->vf.msg_received);

        /* Send request from VF to PF */
        do {
                ret = adf_send_vf2pf_msg(accel_dev, msg);
                if (ret) {
                        dev_err(&GET_DEV(accel_dev),
                                "Failed to send request msg to PF\n");
                        return ret;
                }

                /* Wait for response, if it times out retry */
                ret = wait_for_completion_timeout(&accel_dev->vf.msg_received,
                                                  timeout);
                if (ret) {
                        if (likely(resp))
                                *resp = accel_dev->vf.response;

                        /* Once copied, set to an invalid value */
                        accel_dev->vf.response.type = 0;

                        return 0;
                }

                dev_err(&GET_DEV(accel_dev), "PFVF response message timeout\n");
        } while (--retries);

        return -EIO;
}

static int adf_vf2pf_blkmsg_data_req(struct adf_accel_dev *accel_dev, bool crc,
                                     u8 *type, u8 *data)
{
        struct pfvf_message req = { 0 };
        struct pfvf_message resp = { 0 };
        u8 blk_type;
        u8 blk_byte;
        u8 msg_type;
        u8 max_data;
        int err;

        /* Convert the block type to {small, medium, large} size category */
        if (*type <= ADF_VF2PF_SMALL_BLOCK_TYPE_MAX) {
                msg_type = ADF_VF2PF_MSGTYPE_SMALL_BLOCK_REQ;
                blk_type = FIELD_PREP(ADF_VF2PF_SMALL_BLOCK_TYPE_MASK, *type);
                blk_byte = FIELD_PREP(ADF_VF2PF_SMALL_BLOCK_BYTE_MASK, *data);
                max_data = ADF_VF2PF_SMALL_BLOCK_BYTE_MAX;
        } else if (*type <= ADF_VF2PF_MEDIUM_BLOCK_TYPE_MAX) {
                msg_type = ADF_VF2PF_MSGTYPE_MEDIUM_BLOCK_REQ;
                blk_type = FIELD_PREP(ADF_VF2PF_MEDIUM_BLOCK_TYPE_MASK,
                                      *type - ADF_VF2PF_SMALL_BLOCK_TYPE_MAX);
                blk_byte = FIELD_PREP(ADF_VF2PF_MEDIUM_BLOCK_BYTE_MASK, *data);
                max_data = ADF_VF2PF_MEDIUM_BLOCK_BYTE_MAX;
        } else if (*type <= ADF_VF2PF_LARGE_BLOCK_TYPE_MAX) {
                msg_type = ADF_VF2PF_MSGTYPE_LARGE_BLOCK_REQ;
                blk_type = FIELD_PREP(ADF_VF2PF_LARGE_BLOCK_TYPE_MASK,
                                      *type - ADF_VF2PF_MEDIUM_BLOCK_TYPE_MAX);
                blk_byte = FIELD_PREP(ADF_VF2PF_LARGE_BLOCK_BYTE_MASK, *data);
                max_data = ADF_VF2PF_LARGE_BLOCK_BYTE_MAX;
        } else {
                dev_err(&GET_DEV(accel_dev), "Invalid message type %u\n", *type);
                return -EINVAL;
        }

        /* Sanity check */
        if (*data > max_data) {
                dev_err(&GET_DEV(accel_dev),
                        "Invalid byte %s %u for message type %u\n",
                        crc ? "count" : "index", *data, *type);
                return -EINVAL;
        }

        /* Build the block message */
        req.type = msg_type;
        req.data = blk_type | blk_byte | FIELD_PREP(ADF_VF2PF_BLOCK_CRC_REQ_MASK, crc);

        err = adf_send_vf2pf_req(accel_dev, req, &resp);
        if (err)
                return err;

        *type = FIELD_GET(ADF_PF2VF_BLKMSG_RESP_TYPE_MASK, resp.data);
        *data = FIELD_GET(ADF_PF2VF_BLKMSG_RESP_DATA_MASK, resp.data);

        return 0;
}

static int adf_vf2pf_blkmsg_get_byte(struct adf_accel_dev *accel_dev, u8 type,
                                     u8 index, u8 *data)
{
        int ret;

        ret = adf_vf2pf_blkmsg_data_req(accel_dev, false, &type, &index);
        if (ret < 0)
                return ret;

        if (unlikely(type != ADF_PF2VF_BLKMSG_RESP_TYPE_DATA)) {
                dev_err(&GET_DEV(accel_dev),
                        "Unexpected BLKMSG response type %u, byte 0x%x\n",
                        type, index);
                return -EFAULT;
        }

        *data = index;
        return 0;
}

static int adf_vf2pf_blkmsg_get_crc(struct adf_accel_dev *accel_dev, u8 type,
                                    u8 bytes, u8 *crc)
{
        int ret;

        /* The count of bytes refers to a length, however shift it to a 0-based
         * count to avoid overflows. Thus, a request for 0 bytes is technically
         * valid.
         */
        --bytes;

        ret = adf_vf2pf_blkmsg_data_req(accel_dev, true, &type, &bytes);
        if (ret < 0)
                return ret;

        if (unlikely(type != ADF_PF2VF_BLKMSG_RESP_TYPE_CRC)) {
                dev_err(&GET_DEV(accel_dev),
                        "Unexpected CRC BLKMSG response type %u, crc 0x%x\n",
                        type, bytes);
                return  -EFAULT;
        }

        *crc = bytes;
        return 0;
}

/**
 * adf_send_vf2pf_blkmsg_req() - retrieve block message
 * @accel_dev:  Pointer to acceleration VF device.
 * @type:       The block message type, see adf_pfvf_msg.h for allowed values
 * @buffer:     input buffer where to place the received data
 * @buffer_len: buffer length as input, the amount of written bytes on output
 *
 * Request a message of type 'type' over the block message transport.
 * This function will send the required amount block message requests and
 * return the overall content back to the caller through the provided buffer.
 * The buffer should be large enough to contain the requested message type,
 * otherwise the response will be truncated.
 *
 * Return: 0 on success, error code otherwise.
 */
int adf_send_vf2pf_blkmsg_req(struct adf_accel_dev *accel_dev, u8 type,
                              u8 *buffer, unsigned int *buffer_len)
{
        unsigned int index;
        unsigned int msg_len;
        int ret;
        u8 remote_crc;
        u8 local_crc;

        if (unlikely(type > ADF_VF2PF_LARGE_BLOCK_TYPE_MAX)) {
                dev_err(&GET_DEV(accel_dev), "Invalid block message type %d\n",
                        type);
                return -EINVAL;
        }

        if (unlikely(*buffer_len < ADF_PFVF_BLKMSG_HEADER_SIZE)) {
                dev_err(&GET_DEV(accel_dev),
                        "Buffer size too small for a block message\n");
                return -EINVAL;
        }

        ret = adf_vf2pf_blkmsg_get_byte(accel_dev, type,
                                        ADF_PFVF_BLKMSG_VER_BYTE,
                                        &buffer[ADF_PFVF_BLKMSG_VER_BYTE]);
        if (unlikely(ret))
                return ret;

        if (unlikely(!buffer[ADF_PFVF_BLKMSG_VER_BYTE])) {
                dev_err(&GET_DEV(accel_dev),
                        "Invalid version 0 received for block request %u", type);
                return -EFAULT;
        }

        ret = adf_vf2pf_blkmsg_get_byte(accel_dev, type,
                                        ADF_PFVF_BLKMSG_LEN_BYTE,
                                        &buffer[ADF_PFVF_BLKMSG_LEN_BYTE]);
        if (unlikely(ret))
                return ret;

        if (unlikely(!buffer[ADF_PFVF_BLKMSG_LEN_BYTE])) {
                dev_err(&GET_DEV(accel_dev),
                        "Invalid size 0 received for block request %u", type);
                return -EFAULT;
        }

        /* We need to pick the minimum since there is no way to request a
         * specific version. As a consequence any scenario is possible:
         * - PF has a newer (longer) version which doesn't fit in the buffer
         * - VF expects a newer (longer) version, so we must not ask for
         *   bytes in excess
         * - PF and VF share the same version, no problem
         */
        msg_len = ADF_PFVF_BLKMSG_HEADER_SIZE + buffer[ADF_PFVF_BLKMSG_LEN_BYTE];
        msg_len = min(*buffer_len, msg_len);

        /* Get the payload */
        for (index = ADF_PFVF_BLKMSG_HEADER_SIZE; index < msg_len; index++) {
                ret = adf_vf2pf_blkmsg_get_byte(accel_dev, type, index,
                                                &buffer[index]);
                if (unlikely(ret))
                        return ret;
        }

        ret = adf_vf2pf_blkmsg_get_crc(accel_dev, type, msg_len, &remote_crc);
        if (unlikely(ret))
                return ret;

        local_crc = adf_pfvf_calc_blkmsg_crc(buffer, msg_len);
        if (unlikely(local_crc != remote_crc)) {
                dev_err(&GET_DEV(accel_dev),
                        "CRC error on msg type %d. Local %02X, remote %02X\n",
                        type, local_crc, remote_crc);
                return -EIO;
        }

        *buffer_len = msg_len;
        return 0;
}

static bool adf_handle_pf2vf_msg(struct adf_accel_dev *accel_dev,
                                 struct pfvf_message msg)
{
        switch (msg.type) {
        case ADF_PF2VF_MSGTYPE_RESTARTING:
                dev_dbg(&GET_DEV(accel_dev), "Restarting message received from PF\n");

                adf_pf2vf_handle_pf_restarting(accel_dev);
                return false;
        case ADF_PF2VF_MSGTYPE_RESTARTED:
                dev_dbg(&GET_DEV(accel_dev), "Restarted message received from PF\n");
                return true;
        case ADF_PF2VF_MSGTYPE_FATAL_ERROR:
                dev_err(&GET_DEV(accel_dev), "Fatal error received from PF\n");
                return true;
        case ADF_PF2VF_MSGTYPE_VERSION_RESP:
        case ADF_PF2VF_MSGTYPE_BLKMSG_RESP:
        case ADF_PF2VF_MSGTYPE_RP_RESET_RESP:
                dev_dbg(&GET_DEV(accel_dev),
                        "Response Message received from PF (type 0x%.4x, data 0x%.4x)\n",
                        msg.type, msg.data);
                accel_dev->vf.response = msg;
                complete(&accel_dev->vf.msg_received);
                return true;
        default:
                dev_err(&GET_DEV(accel_dev),
                        "Unknown message from PF (type 0x%.4x, data: 0x%.4x)\n",
                        msg.type, msg.data);
        }

        return false;
}

bool adf_recv_and_handle_pf2vf_msg(struct adf_accel_dev *accel_dev)
{
        struct pfvf_message msg;

        msg = adf_recv_pf2vf_msg(accel_dev);
        if (msg.type)  /* Invalid or no message */
                return adf_handle_pf2vf_msg(accel_dev, msg);

        /* No replies for PF->VF messages at present */

        return true;
}

/**
 * adf_enable_vf2pf_comms() - Function enables communication from vf to pf
 *
 * @accel_dev:  Pointer to acceleration device virtual function.
 *
 * Return: 0 on success, error code otherwise.
 */
int adf_enable_vf2pf_comms(struct adf_accel_dev *accel_dev)
{
        int ret;

        adf_pfvf_crc_init();
        adf_enable_pf2vf_interrupts(accel_dev);

        ret = adf_vf2pf_request_version(accel_dev);
        if (ret)
                return ret;

        ret = adf_vf2pf_get_capabilities(accel_dev);
        if (ret)
                return ret;

        ret = adf_vf2pf_get_ring_to_svc(accel_dev);

        return ret;
}
EXPORT_SYMBOL_GPL(adf_enable_vf2pf_comms);