// SPDX-License-Identifier: GPL-2.0
/*
 * bsg endpoint that supports UPIUs
 *
 * Copyright (C) 2018 Western Digital Corporation
 */
#include "ufs_bsg.h"

static int ufs_bsg_get_query_desc_size(struct ufs_hba *hba, int *desc_len,
                                       struct utp_upiu_query *qr)
{
        int desc_size = be16_to_cpu(qr->length);
        int desc_id = qr->idn;
        int ret;

        if (desc_size <= 0)
                return -EINVAL;

        ret = ufshcd_map_desc_id_to_length(hba, desc_id, desc_len);
        if (ret || !*desc_len)
                return -EINVAL;

        *desc_len = min_t(int, *desc_len, desc_size);

        return 0;
}

static int ufs_bsg_verify_query_size(struct ufs_hba *hba,
                                     unsigned int request_len,
                                     unsigned int reply_len)
{
        int min_req_len = sizeof(struct ufs_bsg_request);
        int min_rsp_len = sizeof(struct ufs_bsg_reply);

        if (min_req_len > request_len || min_rsp_len > reply_len) {
                dev_err(hba->dev, "not enough space assigned\n");
                return -EINVAL;
        }

        return 0;
}

static int ufs_bsg_alloc_desc_buffer(struct ufs_hba *hba, struct bsg_job *job,
                                     uint8_t **desc_buff, int *desc_len,
                                     enum query_opcode desc_op)
{
        struct ufs_bsg_request *bsg_request = job->request;
        struct utp_upiu_query *qr;
        u8 *descp;

        if (desc_op != UPIU_QUERY_OPCODE_WRITE_DESC &&
            desc_op != UPIU_QUERY_OPCODE_READ_DESC)
                goto out;

        qr = &bsg_request->upiu_req.qr;
        if (ufs_bsg_get_query_desc_size(hba, desc_len, qr)) {
                dev_err(hba->dev, "Illegal desc size\n");
                return -EINVAL;
        }

        if (*desc_len > job->request_payload.payload_len) {
                dev_err(hba->dev, "Illegal desc size\n");
                return -EINVAL;
        }

        descp = kzalloc(*desc_len, GFP_KERNEL);
        if (!descp)
                return -ENOMEM;

        if (desc_op == UPIU_QUERY_OPCODE_WRITE_DESC)
                sg_copy_to_buffer(job->request_payload.sg_list,
                                  job->request_payload.sg_cnt, descp,
                                  *desc_len);

        *desc_buff = descp;

out:
        return 0;
}

static int ufs_bsg_request(struct bsg_job *job)
{
        struct ufs_bsg_request *bsg_request = job->request;
        struct ufs_bsg_reply *bsg_reply = job->reply;
        struct ufs_hba *hba = shost_priv(dev_to_shost(job->dev->parent));
        unsigned int req_len = job->request_len;
        unsigned int reply_len = job->reply_len;
        struct uic_command uc = {};
        int msgcode;
        uint8_t *desc_buff = NULL;
        int desc_len = 0;
        enum query_opcode desc_op = UPIU_QUERY_OPCODE_NOP;
        int ret;

        ret = ufs_bsg_verify_query_size(hba, req_len, reply_len);
        if (ret)
                goto out;

        bsg_reply->reply_payload_rcv_len = 0;

        msgcode = bsg_request->msgcode;
        switch (msgcode) {
        case UPIU_TRANSACTION_QUERY_REQ:
                desc_op = bsg_request->upiu_req.qr.opcode;
                ret = ufs_bsg_alloc_desc_buffer(hba, job, &desc_buff,
                                                &desc_len, desc_op);
                if (ret)
                        goto out;

                /* fall through */
        case UPIU_TRANSACTION_NOP_OUT:
        case UPIU_TRANSACTION_TASK_REQ:
                ret = ufshcd_exec_raw_upiu_cmd(hba, &bsg_request->upiu_req,
                                               &bsg_reply->upiu_rsp, msgcode,
                                               desc_buff, &desc_len, desc_op);
                if (ret)
                        dev_err(hba->dev,
                                "exe raw upiu: error code %d\n", ret);

                break;
        case UPIU_TRANSACTION_UIC_CMD:
                memcpy(&uc, &bsg_request->upiu_req.uc, UIC_CMD_SIZE);
                ret = ufshcd_send_uic_cmd(hba, &uc);
                if (ret)
                        dev_dbg(hba->dev,
                                "send uic cmd: error code %d\n", ret);

                memcpy(&bsg_reply->upiu_rsp.uc, &uc, UIC_CMD_SIZE);

                break;
        default:
                ret = -ENOTSUPP;
                dev_err(hba->dev, "unsupported msgcode 0x%x\n", msgcode);

                break;
        }

        if (!desc_buff)
                goto out;

        if (desc_op == UPIU_QUERY_OPCODE_READ_DESC && desc_len)
                bsg_reply->reply_payload_rcv_len =
                        sg_copy_from_buffer(job->request_payload.sg_list,
                                            job->request_payload.sg_cnt,
                                            desc_buff, desc_len);

        kfree(desc_buff);

out:
        bsg_reply->result = ret;
        job->reply_len = sizeof(struct ufs_bsg_reply);
        bsg_job_done(job, ret, bsg_reply->reply_payload_rcv_len);

        return ret;
}

/**
 * ufs_bsg_remove - detach and remove the added ufs-bsg node
 *
 * Should be called when unloading the driver.
 */
void ufs_bsg_remove(struct ufs_hba *hba)
{
        struct device *bsg_dev = &hba->bsg_dev;

        if (!hba->bsg_queue)
                return;

        bsg_remove_queue(hba->bsg_queue);

        device_del(bsg_dev);
        put_device(bsg_dev);
}

static inline void ufs_bsg_node_release(struct device *dev)
{
        put_device(dev->parent);
}

/**
 * ufs_bsg_probe - Add ufs bsg device node
 * @hba: per adapter object
 *
 * Called during initial loading of the driver, and before scsi_scan_host.
 */
int ufs_bsg_probe(struct ufs_hba *hba)
{
        struct device *bsg_dev = &hba->bsg_dev;
        struct Scsi_Host *shost = hba->host;
        struct device *parent = &shost->shost_gendev;
        struct request_queue *q;
        int ret;

        device_initialize(bsg_dev);

        bsg_dev->parent = get_device(parent);
        bsg_dev->release = ufs_bsg_node_release;

        dev_set_name(bsg_dev, "ufs-bsg");

        ret = device_add(bsg_dev);
        if (ret)
                goto out;

        q = bsg_setup_queue(bsg_dev, dev_name(bsg_dev), ufs_bsg_request, NULL, 0);
        if (IS_ERR(q)) {
                ret = PTR_ERR(q);
                goto out;
        }

        hba->bsg_queue = q;

        return 0;

out:
        dev_err(bsg_dev, "fail to initialize a bsg dev %d\n", shost->host_no);
        put_device(bsg_dev);
        return ret;
}