// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2023 Advanced Micro Devices, Inc */

#include <linux/pci.h>

#include "core.h"
#include <linux/pds/pds_auxbus.h>

/**
 * pds_client_register - Link the client to the firmware
 * @pf:         ptr to the PF driver's private data struct
 * @devname:    name that includes service into, e.g. pds_core.vDPA
 *
 * Return: positive client ID (ci) on success, or
 *         negative for error
 */
int pds_client_register(struct pdsc *pf, char *devname)
{
        union pds_core_adminq_comp comp = {};
        union pds_core_adminq_cmd cmd = {};
        int err;
        u16 ci;

        cmd.client_reg.opcode = PDS_AQ_CMD_CLIENT_REG;
        strscpy(cmd.client_reg.devname, devname,
                sizeof(cmd.client_reg.devname));

        err = pdsc_adminq_post(pf, &cmd, &comp, false);
        if (err) {
                dev_info(pf->dev, "register dev_name %s with DSC failed, status %d: %pe\n",
                         devname, comp.status, ERR_PTR(err));
                return err;
        }

        ci = le16_to_cpu(comp.client_reg.client_id);
        if (!ci) {
                dev_err(pf->dev, "%s: device returned null client_id\n",
                        __func__);
                return -EIO;
        }

        dev_dbg(pf->dev, "%s: device returned client_id %d for %s\n",
                __func__, ci, devname);

        return ci;
}
EXPORT_SYMBOL_GPL(pds_client_register);

/**
 * pds_client_unregister - Unlink the client from the firmware
 * @pf:         ptr to the PF driver's private data struct
 * @client_id:  id returned from pds_client_register()
 *
 * Return: 0 on success, or
 *         negative for error
 */
int pds_client_unregister(struct pdsc *pf, u16 client_id)
{
        union pds_core_adminq_comp comp = {};
        union pds_core_adminq_cmd cmd = {};
        int err;

        cmd.client_unreg.opcode = PDS_AQ_CMD_CLIENT_UNREG;
        cmd.client_unreg.client_id = cpu_to_le16(client_id);

        err = pdsc_adminq_post(pf, &cmd, &comp, false);
        if (err)
                dev_info(pf->dev, "unregister client_id %d failed, status %d: %pe\n",
                         client_id, comp.status, ERR_PTR(err));

        return err;
}
EXPORT_SYMBOL_GPL(pds_client_unregister);

/**
 * pds_client_adminq_cmd - Process an adminq request for the client
 * @padev:   ptr to the client device
 * @req:     ptr to buffer with request
 * @req_len: length of actual struct used for request
 * @resp:    ptr to buffer where answer is to be copied
 * @flags:   optional flags from pds_core_adminq_flags
 *
 * Return: 0 on success, or
 *         negative for error
 *
 * Client sends pointers to request and response buffers
 * Core copies request data into pds_core_client_request_cmd
 * Core sets other fields as needed
 * Core posts to AdminQ
 * Core copies completion data into response buffer
 */
int pds_client_adminq_cmd(struct pds_auxiliary_dev *padev,
                          union pds_core_adminq_cmd *req,
                          size_t req_len,
                          union pds_core_adminq_comp *resp,
                          u64 flags)
{
        union pds_core_adminq_cmd cmd = {};
        struct pci_dev *pf_pdev;
        struct pdsc *pf;
        size_t cp_len;
        int err;

        pf_pdev = pci_physfn(padev->vf_pdev);
        pf = pci_get_drvdata(pf_pdev);

        dev_dbg(pf->dev, "%s: %s opcode %d\n",
                __func__, dev_name(&padev->aux_dev.dev), req->opcode);

        /* Wrap the client's request */
        cmd.client_request.opcode = PDS_AQ_CMD_CLIENT_CMD;
        cmd.client_request.client_id = cpu_to_le16(padev->client_id);
        cp_len = min_t(size_t, req_len, sizeof(cmd.client_request.client_cmd));
        memcpy(cmd.client_request.client_cmd, req, cp_len);

        err = pdsc_adminq_post(pf, &cmd, resp,
                               !!(flags & PDS_AQ_FLAG_FASTPOLL));
        if (err && err != -EAGAIN)
                dev_info(pf->dev, "client admin cmd failed: %pe\n",
                         ERR_PTR(err));

        return err;
}
EXPORT_SYMBOL_GPL(pds_client_adminq_cmd);

static void pdsc_auxbus_dev_release(struct device *dev)
{
        struct pds_auxiliary_dev *padev =
                container_of(dev, struct pds_auxiliary_dev, aux_dev.dev);

        kfree(padev);
}

static struct pds_auxiliary_dev *pdsc_auxbus_dev_register(struct pdsc *cf,
                                                          struct pdsc *pf,
                                                          u16 client_id,
                                                          char *name)
{
        struct auxiliary_device *aux_dev;
        struct pds_auxiliary_dev *padev;
        int err;

        padev = kzalloc_obj(*padev);
        if (!padev)
                return ERR_PTR(-ENOMEM);

        padev->vf_pdev = cf->pdev;
        padev->client_id = client_id;

        aux_dev = &padev->aux_dev;
        aux_dev->name = name;
        aux_dev->id = cf->uid;
        aux_dev->dev.parent = cf->dev;
        aux_dev->dev.release = pdsc_auxbus_dev_release;

        err = auxiliary_device_init(aux_dev);
        if (err < 0) {
                dev_warn(cf->dev, "auxiliary_device_init of %s failed: %pe\n",
                         name, ERR_PTR(err));
                kfree(padev);
                return ERR_PTR(err);
        }

        err = auxiliary_device_add(aux_dev);
        if (err) {
                dev_warn(cf->dev, "auxiliary_device_add of %s failed: %pe\n",
                         name, ERR_PTR(err));
                auxiliary_device_uninit(aux_dev);
                return ERR_PTR(err);
        }

        return padev;
}

void pdsc_auxbus_dev_del(struct pdsc *cf, struct pdsc *pf,
                         struct pds_auxiliary_dev **pd_ptr)
{
        struct pds_auxiliary_dev *padev;

        if (!*pd_ptr)
                return;

        mutex_lock(&pf->config_lock);

        padev = *pd_ptr;
        pds_client_unregister(pf, padev->client_id);
        auxiliary_device_delete(&padev->aux_dev);
        auxiliary_device_uninit(&padev->aux_dev);
        *pd_ptr = NULL;

        mutex_unlock(&pf->config_lock);
}

int pdsc_auxbus_dev_add(struct pdsc *cf, struct pdsc *pf,
                        enum pds_core_vif_types vt,
                        struct pds_auxiliary_dev **pd_ptr)
{
        struct pds_auxiliary_dev *padev;
        char devname[PDS_DEVNAME_LEN];
        unsigned long mask;
        u16 vt_support;
        int client_id;
        int err = 0;

        if (!cf)
                return -ENODEV;

        if (vt >= PDS_DEV_TYPE_MAX)
                return -EINVAL;

        mutex_lock(&pf->config_lock);

        mask = BIT_ULL(PDSC_S_FW_DEAD) |
               BIT_ULL(PDSC_S_STOPPING_DRIVER);
        if (cf->state & mask) {
                dev_err(pf->dev, "%s: can't add dev, VF client in bad state %#lx\n",
                        __func__, cf->state);
                err = -ENXIO;
                goto out_unlock;
        }

        /* Verify that the type is supported and enabled.  It is not
         * an error if the firmware doesn't support the feature, the
         * driver just won't set up an auxiliary_device for it.
         */
        vt_support = !!le16_to_cpu(pf->dev_ident.vif_types[vt]);
        if (!(vt_support &&
              pf->viftype_status[vt].supported &&
              pf->viftype_status[vt].enabled))
                goto out_unlock;

        /* Need to register with FW and get the client_id before
         * creating the aux device so that the aux client can run
         * adminq commands as part its probe
         */
        snprintf(devname, sizeof(devname), "%s.%s.%d",
                 PDS_CORE_DRV_NAME, pf->viftype_status[vt].name, cf->uid);
        client_id = pds_client_register(pf, devname);
        if (client_id < 0) {
                err = client_id;
                goto out_unlock;
        }

        padev = pdsc_auxbus_dev_register(cf, pf, client_id,
                                         pf->viftype_status[vt].name);
        if (IS_ERR(padev)) {
                pds_client_unregister(pf, client_id);
                err = PTR_ERR(padev);
                goto out_unlock;
        }
        *pd_ptr = padev;

out_unlock:
        mutex_unlock(&pf->config_lock);
        return err;
}