// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2013, Intel Corporation.
 *
 * MEI Library for mei bus nfc device access
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/nfc.h>

#include "mei_phy.h"

struct mei_nfc_hdr {
        u8 cmd;
        u8 status;
        u16 req_id;
        u32 reserved;
        u16 data_size;
} __packed;

struct mei_nfc_cmd {
        struct mei_nfc_hdr hdr;
        u8 sub_command;
        u8 data[];
} __packed;

struct mei_nfc_reply {
        struct mei_nfc_hdr hdr;
        u8 sub_command;
        u8 reply_status;
        u8 data[];
} __packed;

struct mei_nfc_if_version {
        u8 radio_version_sw[3];
        u8 reserved[3];
        u8 radio_version_hw[3];
        u8 i2c_addr;
        u8 fw_ivn;
        u8 vendor_id;
        u8 radio_type;
} __packed;

struct mei_nfc_connect {
        u8 fw_ivn;
        u8 vendor_id;
} __packed;

struct mei_nfc_connect_resp {
        u8 fw_ivn;
        u8 vendor_id;
        u16 me_major;
        u16 me_minor;
        u16 me_hotfix;
        u16 me_build;
} __packed;


#define MEI_NFC_CMD_MAINTENANCE 0x00
#define MEI_NFC_CMD_HCI_SEND 0x01
#define MEI_NFC_CMD_HCI_RECV 0x02

#define MEI_NFC_SUBCMD_CONNECT    0x00
#define MEI_NFC_SUBCMD_IF_VERSION 0x01

#define MEI_NFC_MAX_READ (MEI_NFC_HEADER_SIZE + MEI_NFC_MAX_HCI_PAYLOAD)

#define MEI_DUMP_SKB_IN(info, skb)                              \
do {                                                            \
        pr_debug("%s:\n", info);                                \
        print_hex_dump_debug("mei in : ", DUMP_PREFIX_OFFSET,   \
                        16, 1, (skb)->data, (skb)->len, false); \
} while (0)

#define MEI_DUMP_SKB_OUT(info, skb)                             \
do {                                                            \
        pr_debug("%s:\n", info);                                \
        print_hex_dump_debug("mei out: ", DUMP_PREFIX_OFFSET,   \
                        16, 1, (skb)->data, (skb)->len, false); \
} while (0)

#define MEI_DUMP_NFC_HDR(info, _hdr)                                \
do {                                                                \
        pr_debug("%s:\n", info);                                    \
        pr_debug("cmd=%02d status=%d req_id=%d rsvd=%d size=%d\n",  \
                 (_hdr)->cmd, (_hdr)->status, (_hdr)->req_id,       \
                 (_hdr)->reserved, (_hdr)->data_size);              \
} while (0)

static int mei_nfc_if_version(struct nfc_mei_phy *phy)
{

        struct mei_nfc_cmd cmd;
        struct mei_nfc_reply *reply = NULL;
        struct mei_nfc_if_version *version;
        size_t if_version_length;
        int bytes_recv, r;

        memset(&cmd, 0, sizeof(struct mei_nfc_cmd));
        cmd.hdr.cmd = MEI_NFC_CMD_MAINTENANCE;
        cmd.hdr.data_size = 1;
        cmd.sub_command = MEI_NFC_SUBCMD_IF_VERSION;

        MEI_DUMP_NFC_HDR("version", &cmd.hdr);
        r = mei_cldev_send(phy->cldev, (u8 *)&cmd, sizeof(struct mei_nfc_cmd));
        if (r < 0) {
                pr_err("Could not send IF version cmd\n");
                return r;
        }

        /* to be sure on the stack we alloc memory */
        if_version_length = sizeof(struct mei_nfc_reply) +
                sizeof(struct mei_nfc_if_version);

        reply = kzalloc(if_version_length, GFP_KERNEL);
        if (!reply)
                return -ENOMEM;

        bytes_recv = mei_cldev_recv(phy->cldev, (u8 *)reply, if_version_length);
        if (bytes_recv < 0 || bytes_recv < if_version_length) {
                pr_err("Could not read IF version\n");
                r = -EIO;
                goto err;
        }

        version = (struct mei_nfc_if_version *)reply->data;

        phy->fw_ivn = version->fw_ivn;
        phy->vendor_id = version->vendor_id;
        phy->radio_type = version->radio_type;

err:
        kfree(reply);
        return r;
}

static int mei_nfc_connect(struct nfc_mei_phy *phy)
{
        struct mei_nfc_cmd *cmd, *reply;
        struct mei_nfc_connect *connect;
        struct mei_nfc_connect_resp *connect_resp;
        size_t connect_length, connect_resp_length;
        int bytes_recv, r;

        connect_length = sizeof(struct mei_nfc_cmd) +
                        sizeof(struct mei_nfc_connect);

        connect_resp_length = sizeof(struct mei_nfc_cmd) +
                        sizeof(struct mei_nfc_connect_resp);

        cmd = kzalloc(connect_length, GFP_KERNEL);
        if (!cmd)
                return -ENOMEM;
        connect = (struct mei_nfc_connect *)cmd->data;

        reply = kzalloc(connect_resp_length, GFP_KERNEL);
        if (!reply) {
                kfree(cmd);
                return -ENOMEM;
        }

        connect_resp = (struct mei_nfc_connect_resp *)reply->data;

        cmd->hdr.cmd = MEI_NFC_CMD_MAINTENANCE;
        cmd->hdr.data_size = 3;
        cmd->sub_command = MEI_NFC_SUBCMD_CONNECT;
        connect->fw_ivn = phy->fw_ivn;
        connect->vendor_id = phy->vendor_id;

        MEI_DUMP_NFC_HDR("connect request", &cmd->hdr);
        r = mei_cldev_send(phy->cldev, (u8 *)cmd, connect_length);
        if (r < 0) {
                pr_err("Could not send connect cmd %d\n", r);
                goto err;
        }

        bytes_recv = mei_cldev_recv(phy->cldev, (u8 *)reply,
                                    connect_resp_length);
        if (bytes_recv < 0) {
                r = bytes_recv;
                pr_err("Could not read connect response %d\n", r);
                goto err;
        }

        MEI_DUMP_NFC_HDR("connect reply", &reply->hdr);

        pr_info("IVN 0x%x Vendor ID 0x%x\n",
                 connect_resp->fw_ivn, connect_resp->vendor_id);

        pr_info("ME FW %d.%d.%d.%d\n",
                connect_resp->me_major, connect_resp->me_minor,
                connect_resp->me_hotfix, connect_resp->me_build);

        r = 0;

err:
        kfree(reply);
        kfree(cmd);

        return r;
}

static int mei_nfc_send(struct nfc_mei_phy *phy, const u8 *buf, size_t length)
{
        struct mei_nfc_hdr *hdr;
        u8 *mei_buf;
        int err;

        err = -ENOMEM;
        mei_buf = kzalloc(length + MEI_NFC_HEADER_SIZE, GFP_KERNEL);
        if (!mei_buf)
                goto out;

        hdr = (struct mei_nfc_hdr *)mei_buf;
        hdr->cmd = MEI_NFC_CMD_HCI_SEND;
        hdr->status = 0;
        hdr->req_id = phy->req_id;
        hdr->reserved = 0;
        hdr->data_size = length;

        MEI_DUMP_NFC_HDR("send", hdr);

        memcpy(mei_buf + MEI_NFC_HEADER_SIZE, buf, length);
        err = mei_cldev_send(phy->cldev, mei_buf, length + MEI_NFC_HEADER_SIZE);
        if (err < 0)
                goto out;

        if (!wait_event_interruptible_timeout(phy->send_wq,
                                phy->recv_req_id == phy->req_id, HZ)) {
                pr_err("NFC MEI command timeout\n");
                err = -ETIME;
        } else {
                phy->req_id++;
        }
out:
        kfree(mei_buf);
        return err;
}

/*
 * Writing a frame must not return the number of written bytes.
 * It must return either zero for success, or <0 for error.
 * In addition, it must not alter the skb
 */
static int nfc_mei_phy_write(void *phy_id, struct sk_buff *skb)
{
        struct nfc_mei_phy *phy = phy_id;
        int r;

        MEI_DUMP_SKB_OUT("mei frame sent", skb);

        r = mei_nfc_send(phy, skb->data, skb->len);
        if (r > 0)
                r = 0;

        return r;
}

static int mei_nfc_recv(struct nfc_mei_phy *phy, u8 *buf, size_t length)
{
        struct mei_nfc_hdr *hdr;
        int received_length;

        received_length = mei_cldev_recv(phy->cldev, buf, length);
        if (received_length < 0)
                return received_length;

        hdr = (struct mei_nfc_hdr *) buf;

        MEI_DUMP_NFC_HDR("receive", hdr);
        if (hdr->cmd == MEI_NFC_CMD_HCI_SEND) {
                phy->recv_req_id = hdr->req_id;
                wake_up(&phy->send_wq);

                return 0;
        }

        return received_length;
}


static void nfc_mei_rx_cb(struct mei_cl_device *cldev)
{
        struct nfc_mei_phy *phy = mei_cldev_get_drvdata(cldev);
        struct sk_buff *skb;
        int reply_size;

        if (!phy)
                return;

        if (phy->hard_fault != 0)
                return;

        skb = alloc_skb(MEI_NFC_MAX_READ, GFP_KERNEL);
        if (!skb)
                return;

        reply_size = mei_nfc_recv(phy, skb->data, MEI_NFC_MAX_READ);
        if (reply_size < MEI_NFC_HEADER_SIZE) {
                kfree_skb(skb);
                return;
        }

        skb_put(skb, reply_size);
        skb_pull(skb, MEI_NFC_HEADER_SIZE);

        MEI_DUMP_SKB_IN("mei frame read", skb);

        nfc_hci_recv_frame(phy->hdev, skb);
}

static int nfc_mei_phy_enable(void *phy_id)
{
        int r;
        struct nfc_mei_phy *phy = phy_id;

        if (phy->powered == 1)
                return 0;

        r = mei_cldev_enable(phy->cldev);
        if (r < 0) {
                pr_err("Could not enable device %d\n", r);
                return r;
        }

        r = mei_nfc_if_version(phy);
        if (r < 0) {
                pr_err("Could not enable device %d\n", r);
                goto err;
        }

        r = mei_nfc_connect(phy);
        if (r < 0) {
                pr_err("Could not connect to device %d\n", r);
                goto err;
        }

        r = mei_cldev_register_rx_cb(phy->cldev, nfc_mei_rx_cb);
        if (r) {
                pr_err("Event cb registration failed %d\n", r);
                goto err;
        }

        phy->powered = 1;

        return 0;

err:
        phy->powered = 0;
        mei_cldev_disable(phy->cldev);
        return r;
}

static void nfc_mei_phy_disable(void *phy_id)
{
        struct nfc_mei_phy *phy = phy_id;

        mei_cldev_disable(phy->cldev);

        phy->powered = 0;
}

const struct nfc_phy_ops mei_phy_ops = {
        .write = nfc_mei_phy_write,
        .enable = nfc_mei_phy_enable,
        .disable = nfc_mei_phy_disable,
};
EXPORT_SYMBOL_GPL(mei_phy_ops);

struct nfc_mei_phy *nfc_mei_phy_alloc(struct mei_cl_device *cldev)
{
        struct nfc_mei_phy *phy;

        phy = kzalloc_obj(struct nfc_mei_phy);
        if (!phy)
                return NULL;

        phy->cldev = cldev;
        init_waitqueue_head(&phy->send_wq);
        mei_cldev_set_drvdata(cldev, phy);

        return phy;
}
EXPORT_SYMBOL_GPL(nfc_mei_phy_alloc);

void nfc_mei_phy_free(struct nfc_mei_phy *phy)
{
        mei_cldev_disable(phy->cldev);
        kfree(phy);
}
EXPORT_SYMBOL_GPL(nfc_mei_phy_free);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("mei bus NFC device interface");