// SPDX-License-Identifier: GPL-2.0
/*
 * ISM driver for s390.
 *
 * Copyright IBM Corp. 2018
 */
#define pr_fmt(fmt) "ism: " fmt

#include <linux/export.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/ctype.h>
#include <linux/processor.h>

#include "ism.h"

MODULE_DESCRIPTION("ISM driver for s390");
MODULE_LICENSE("GPL");

#define DRV_NAME "ism"

static const struct pci_device_id ism_device_table[] = {
        { PCI_VDEVICE(IBM, PCI_DEVICE_ID_IBM_ISM), 0 },
        { 0, }
};
MODULE_DEVICE_TABLE(pci, ism_device_table);

static debug_info_t *ism_debug_info;

static int ism_cmd(struct ism_dev *ism, void *cmd)
{
        struct ism_req_hdr *req = cmd;
        struct ism_resp_hdr *resp = cmd;

        spin_lock(&ism->cmd_lock);
        __ism_write_cmd(ism, req + 1, sizeof(*req), req->len - sizeof(*req));
        __ism_write_cmd(ism, req, 0, sizeof(*req));

        WRITE_ONCE(resp->ret, ISM_ERROR);

        __ism_read_cmd(ism, resp, 0, sizeof(*resp));
        if (resp->ret) {
                debug_text_event(ism_debug_info, 0, "cmd failure");
                debug_event(ism_debug_info, 0, resp, sizeof(*resp));
                goto out;
        }
        __ism_read_cmd(ism, resp + 1, sizeof(*resp), resp->len - sizeof(*resp));
out:
        spin_unlock(&ism->cmd_lock);
        return resp->ret;
}

static int ism_cmd_simple(struct ism_dev *ism, u32 cmd_code)
{
        union ism_cmd_simple cmd;

        memset(&cmd, 0, sizeof(cmd));
        cmd.request.hdr.cmd = cmd_code;
        cmd.request.hdr.len = sizeof(cmd.request);

        return ism_cmd(ism, &cmd);
}

static int query_info(struct ism_dev *ism)
{
        union ism_qi cmd;

        memset(&cmd, 0, sizeof(cmd));
        cmd.request.hdr.cmd = ISM_QUERY_INFO;
        cmd.request.hdr.len = sizeof(cmd.request);

        if (ism_cmd(ism, &cmd))
                goto out;

        debug_text_event(ism_debug_info, 3, "query info");
        debug_event(ism_debug_info, 3, &cmd.response, sizeof(cmd.response));
out:
        return 0;
}

static int register_sba(struct ism_dev *ism)
{
        union ism_reg_sba cmd;
        dma_addr_t dma_handle;
        struct ism_sba *sba;

        sba = dma_alloc_coherent(&ism->pdev->dev, PAGE_SIZE, &dma_handle,
                                 GFP_KERNEL);
        if (!sba)
                return -ENOMEM;

        memset(&cmd, 0, sizeof(cmd));
        cmd.request.hdr.cmd = ISM_REG_SBA;
        cmd.request.hdr.len = sizeof(cmd.request);
        cmd.request.sba = dma_handle;

        if (ism_cmd(ism, &cmd)) {
                dma_free_coherent(&ism->pdev->dev, PAGE_SIZE, sba, dma_handle);
                return -EIO;
        }

        ism->sba = sba;
        ism->sba_dma_addr = dma_handle;

        return 0;
}

static int register_ieq(struct ism_dev *ism)
{
        union ism_reg_ieq cmd;
        dma_addr_t dma_handle;
        struct ism_eq *ieq;

        ieq = dma_alloc_coherent(&ism->pdev->dev, PAGE_SIZE, &dma_handle,
                                 GFP_KERNEL);
        if (!ieq)
                return -ENOMEM;

        memset(&cmd, 0, sizeof(cmd));
        cmd.request.hdr.cmd = ISM_REG_IEQ;
        cmd.request.hdr.len = sizeof(cmd.request);
        cmd.request.ieq = dma_handle;
        cmd.request.len = sizeof(*ieq);

        if (ism_cmd(ism, &cmd)) {
                dma_free_coherent(&ism->pdev->dev, PAGE_SIZE, ieq, dma_handle);
                return -EIO;
        }

        ism->ieq = ieq;
        ism->ieq_idx = -1;
        ism->ieq_dma_addr = dma_handle;

        return 0;
}

static int unregister_sba(struct ism_dev *ism)
{
        int ret;

        if (!ism->sba)
                return 0;

        ret = ism_cmd_simple(ism, ISM_UNREG_SBA);
        if (ret && ret != ISM_ERROR)
                return -EIO;

        dma_free_coherent(&ism->pdev->dev, PAGE_SIZE,
                          ism->sba, ism->sba_dma_addr);

        ism->sba = NULL;
        ism->sba_dma_addr = 0;

        return 0;
}

static int unregister_ieq(struct ism_dev *ism)
{
        int ret;

        if (!ism->ieq)
                return 0;

        ret = ism_cmd_simple(ism, ISM_UNREG_IEQ);
        if (ret && ret != ISM_ERROR)
                return -EIO;

        dma_free_coherent(&ism->pdev->dev, PAGE_SIZE,
                          ism->ieq, ism->ieq_dma_addr);

        ism->ieq = NULL;
        ism->ieq_dma_addr = 0;

        return 0;
}

static int ism_read_local_gid(struct dibs_dev *dibs)
{
        struct ism_dev *ism = dibs->drv_priv;
        union ism_read_gid cmd;
        int ret;

        memset(&cmd, 0, sizeof(cmd));
        cmd.request.hdr.cmd = ISM_READ_GID;
        cmd.request.hdr.len = sizeof(cmd.request);

        ret = ism_cmd(ism, &cmd);
        if (ret)
                goto out;

        memset(&dibs->gid, 0, sizeof(dibs->gid));
        memcpy(&dibs->gid, &cmd.response.gid, sizeof(cmd.response.gid));
out:
        return ret;
}

static int ism_query_rgid(struct dibs_dev *dibs, const uuid_t *rgid,
                          u32 vid_valid, u32 vid)
{
        struct ism_dev *ism = dibs->drv_priv;
        union ism_query_rgid cmd;

        memset(&cmd, 0, sizeof(cmd));
        cmd.request.hdr.cmd = ISM_QUERY_RGID;
        cmd.request.hdr.len = sizeof(cmd.request);

        memcpy(&cmd.request.rgid, rgid, sizeof(cmd.request.rgid));
        cmd.request.vlan_valid = vid_valid;
        cmd.request.vlan_id = vid;

        return ism_cmd(ism, &cmd);
}

static int ism_max_dmbs(void)
{
        return ISM_NR_DMBS;
}

static void ism_free_dmb(struct ism_dev *ism, struct dibs_dmb *dmb)
{
        clear_bit(dmb->idx, ism->sba_bitmap);
        dma_unmap_page(&ism->pdev->dev, dmb->dma_addr, dmb->dmb_len,
                       DMA_FROM_DEVICE);
        folio_put(virt_to_folio(dmb->cpu_addr));
}

static int ism_alloc_dmb(struct ism_dev *ism, struct dibs_dmb *dmb)
{
        struct folio *folio;
        unsigned long bit;
        int rc;

        if (PAGE_ALIGN(dmb->dmb_len) > dma_get_max_seg_size(&ism->pdev->dev))
                return -EINVAL;

        if (!dmb->idx) {
                bit = find_next_zero_bit(ism->sba_bitmap, ISM_NR_DMBS,
                                         ISM_DMB_BIT_OFFSET);
                if (bit == ISM_NR_DMBS)
                        return -ENOSPC;

                dmb->idx = bit;
        }
        if (dmb->idx < ISM_DMB_BIT_OFFSET ||
            test_and_set_bit(dmb->idx, ism->sba_bitmap))
                return -EINVAL;

        folio = folio_alloc(GFP_KERNEL | __GFP_NOWARN | __GFP_NOMEMALLOC |
                            __GFP_NORETRY, get_order(dmb->dmb_len));

        if (!folio) {
                rc = -ENOMEM;
                goto out_bit;
        }

        dmb->cpu_addr = folio_address(folio);
        dmb->dma_addr = dma_map_page(&ism->pdev->dev,
                                     virt_to_page(dmb->cpu_addr), 0,
                                     dmb->dmb_len, DMA_FROM_DEVICE);
        if (dma_mapping_error(&ism->pdev->dev, dmb->dma_addr)) {
                rc = -ENOMEM;
                goto out_free;
        }

        return 0;

out_free:
        kfree(dmb->cpu_addr);
out_bit:
        clear_bit(dmb->idx, ism->sba_bitmap);
        return rc;
}

static int ism_register_dmb(struct dibs_dev *dibs, struct dibs_dmb *dmb,
                            struct dibs_client *client)
{
        struct ism_dev *ism = dibs->drv_priv;
        union ism_reg_dmb cmd;
        unsigned long flags;
        int ret;

        ret = ism_alloc_dmb(ism, dmb);
        if (ret)
                goto out;

        memset(&cmd, 0, sizeof(cmd));
        cmd.request.hdr.cmd = ISM_REG_DMB;
        cmd.request.hdr.len = sizeof(cmd.request);

        cmd.request.dmb = dmb->dma_addr;
        cmd.request.dmb_len = dmb->dmb_len;
        cmd.request.sba_idx = dmb->idx;
        cmd.request.vlan_valid = dmb->vlan_valid;
        cmd.request.vlan_id = dmb->vlan_id;
        memcpy(&cmd.request.rgid, &dmb->rgid, sizeof(u64));

        ret = ism_cmd(ism, &cmd);
        if (ret) {
                ism_free_dmb(ism, dmb);
                goto out;
        }
        dmb->dmb_tok = cmd.response.dmb_tok;
        spin_lock_irqsave(&dibs->lock, flags);
        dibs->dmb_clientid_arr[dmb->idx - ISM_DMB_BIT_OFFSET] = client->id;
        spin_unlock_irqrestore(&dibs->lock, flags);
out:
        return ret;
}

static int ism_unregister_dmb(struct dibs_dev *dibs, struct dibs_dmb *dmb)
{
        struct ism_dev *ism = dibs->drv_priv;
        union ism_unreg_dmb cmd;
        unsigned long flags;
        int ret;

        memset(&cmd, 0, sizeof(cmd));
        cmd.request.hdr.cmd = ISM_UNREG_DMB;
        cmd.request.hdr.len = sizeof(cmd.request);

        cmd.request.dmb_tok = dmb->dmb_tok;

        spin_lock_irqsave(&dibs->lock, flags);
        dibs->dmb_clientid_arr[dmb->idx - ISM_DMB_BIT_OFFSET] = NO_DIBS_CLIENT;
        spin_unlock_irqrestore(&dibs->lock, flags);

        ret = ism_cmd(ism, &cmd);
        if (ret && ret != ISM_ERROR)
                goto out;

        ism_free_dmb(ism, dmb);
out:
        return ret;
}

static int ism_add_vlan_id(struct dibs_dev *dibs, u64 vlan_id)
{
        struct ism_dev *ism = dibs->drv_priv;
        union ism_set_vlan_id cmd;

        memset(&cmd, 0, sizeof(cmd));
        cmd.request.hdr.cmd = ISM_ADD_VLAN_ID;
        cmd.request.hdr.len = sizeof(cmd.request);

        cmd.request.vlan_id = vlan_id;

        return ism_cmd(ism, &cmd);
}

static int ism_del_vlan_id(struct dibs_dev *dibs, u64 vlan_id)
{
        struct ism_dev *ism = dibs->drv_priv;
        union ism_set_vlan_id cmd;

        memset(&cmd, 0, sizeof(cmd));
        cmd.request.hdr.cmd = ISM_DEL_VLAN_ID;
        cmd.request.hdr.len = sizeof(cmd.request);

        cmd.request.vlan_id = vlan_id;

        return ism_cmd(ism, &cmd);
}

static int ism_signal_ieq(struct dibs_dev *dibs, const uuid_t *rgid,
                          u32 trigger_irq, u32 event_code, u64 info)
{
        struct ism_dev *ism = dibs->drv_priv;
        union ism_sig_ieq cmd;

        memset(&cmd, 0, sizeof(cmd));
        cmd.request.hdr.cmd = ISM_SIGNAL_IEQ;
        cmd.request.hdr.len = sizeof(cmd.request);

        memcpy(&cmd.request.rgid, rgid, sizeof(cmd.request.rgid));
        cmd.request.trigger_irq = trigger_irq;
        cmd.request.event_code = event_code;
        cmd.request.info = info;

        return ism_cmd(ism, &cmd);
}

static unsigned int max_bytes(unsigned int start, unsigned int len,
                              unsigned int boundary)
{
        return min(boundary - (start & (boundary - 1)), len);
}

static int ism_move(struct dibs_dev *dibs, u64 dmb_tok, unsigned int idx,
                    bool sf, unsigned int offset, void *data,
                    unsigned int size)
{
        struct ism_dev *ism = dibs->drv_priv;
        unsigned int bytes;
        u64 dmb_req;
        int ret;

        while (size) {
                bytes = max_bytes(offset, size, PAGE_SIZE);
                dmb_req = ISM_CREATE_REQ(dmb_tok, idx, size == bytes ? sf : 0,
                                         offset);

                ret = __ism_move(ism, dmb_req, data, bytes);
                if (ret)
                        return ret;

                size -= bytes;
                data += bytes;
                offset += bytes;
        }

        return 0;
}

static u16 ism_get_chid(struct dibs_dev *dibs)
{
        struct ism_dev *ism = dibs->drv_priv;

        if (!ism || !ism->pdev)
                return 0;

        return to_zpci(ism->pdev)->pchid;
}

static int ism_match_event_type(u32 s390_event_type)
{
        switch (s390_event_type) {
        case ISM_EVENT_BUF:
                return DIBS_BUF_EVENT;
        case ISM_EVENT_DEV:
                return DIBS_DEV_EVENT;
        case ISM_EVENT_SWR:
                return DIBS_SW_EVENT;
        default:
                return DIBS_OTHER_TYPE;
        }
}

static int ism_match_event_subtype(u32 s390_event_subtype)
{
        switch (s390_event_subtype) {
        case ISM_BUF_DMB_UNREGISTERED:
                return DIBS_BUF_UNREGISTERED;
        case ISM_DEV_GID_DISABLED:
                return DIBS_DEV_DISABLED;
        case ISM_DEV_GID_ERR_STATE:
                return DIBS_DEV_ERR_STATE;
        default:
                return DIBS_OTHER_SUBTYPE;
        }
}

static void ism_handle_event(struct ism_dev *ism)
{
        struct dibs_dev *dibs = ism->dibs;
        struct dibs_event event;
        struct ism_event *entry;
        struct dibs_client *clt;
        int i;

        while ((ism->ieq_idx + 1) != READ_ONCE(ism->ieq->header.idx)) {
                if (++ism->ieq_idx == ARRAY_SIZE(ism->ieq->entry))
                        ism->ieq_idx = 0;

                entry = &ism->ieq->entry[ism->ieq_idx];
                debug_event(ism_debug_info, 2, entry, sizeof(*entry));
                __memset(&event, 0, sizeof(event));
                event.type = ism_match_event_type(entry->type);
                if (event.type == DIBS_SW_EVENT)
                        event.subtype = entry->code;
                else
                        event.subtype = ism_match_event_subtype(entry->code);
                event.time = entry->time;
                event.data = entry->info;
                switch (event.type) {
                case DIBS_BUF_EVENT:
                        event.buffer_tok = entry->tok;
                        break;
                case DIBS_DEV_EVENT:
                case DIBS_SW_EVENT:
                        memcpy(&event.gid, &entry->tok, sizeof(u64));
                }
                for (i = 0; i < MAX_DIBS_CLIENTS; ++i) {
                        clt = dibs->subs[i];
                        if (clt)
                                clt->ops->handle_event(dibs, &event);
                }
        }
}

static irqreturn_t ism_handle_irq(int irq, void *data)
{
        struct ism_dev *ism = data;
        unsigned long bit, end;
        struct dibs_dev *dibs;
        unsigned long *bv;
        u16 dmbemask;
        u8 client_id;

        dibs = ism->dibs;

        bv = (void *) &ism->sba->dmb_bits[ISM_DMB_WORD_OFFSET];
        end = sizeof(ism->sba->dmb_bits) * BITS_PER_BYTE - ISM_DMB_BIT_OFFSET;

        spin_lock(&dibs->lock);
        ism->sba->s = 0;
        barrier();
        for (bit = 0;;) {
                bit = find_next_bit_inv(bv, end, bit);
                if (bit >= end)
                        break;

                clear_bit_inv(bit, bv);
                dmbemask = ism->sba->dmbe_mask[bit + ISM_DMB_BIT_OFFSET];
                ism->sba->dmbe_mask[bit + ISM_DMB_BIT_OFFSET] = 0;
                barrier();
                client_id = dibs->dmb_clientid_arr[bit];
                if (unlikely(client_id == NO_DIBS_CLIENT ||
                             !dibs->subs[client_id]))
                        continue;
                dibs->subs[client_id]->ops->handle_irq(dibs,
                                                       bit + ISM_DMB_BIT_OFFSET,
                                                       dmbemask);
        }

        if (ism->sba->e) {
                ism->sba->e = 0;
                barrier();
                ism_handle_event(ism);
        }
        spin_unlock(&dibs->lock);
        return IRQ_HANDLED;
}

static const struct dibs_dev_ops ism_ops = {
        .get_fabric_id = ism_get_chid,
        .query_remote_gid = ism_query_rgid,
        .max_dmbs = ism_max_dmbs,
        .register_dmb = ism_register_dmb,
        .unregister_dmb = ism_unregister_dmb,
        .move_data = ism_move,
        .add_vlan_id = ism_add_vlan_id,
        .del_vlan_id = ism_del_vlan_id,
        .signal_event = ism_signal_ieq,
};

static int ism_dev_init(struct ism_dev *ism)
{
        struct pci_dev *pdev = ism->pdev;
        int ret;

        ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI);
        if (ret <= 0)
                goto out;

        ret = request_irq(pci_irq_vector(pdev, 0), ism_handle_irq, 0,
                          pci_name(pdev), ism);
        if (ret)
                goto free_vectors;

        ret = register_sba(ism);
        if (ret)
                goto free_irq;

        ret = register_ieq(ism);
        if (ret)
                goto unreg_sba;

        query_info(ism);
        return 0;

unreg_sba:
        unregister_sba(ism);
free_irq:
        free_irq(pci_irq_vector(pdev, 0), ism);
free_vectors:
        pci_free_irq_vectors(pdev);
out:
        return ret;
}

static void ism_dev_exit(struct ism_dev *ism)
{
        struct pci_dev *pdev = ism->pdev;

        unregister_ieq(ism);
        unregister_sba(ism);
        free_irq(pci_irq_vector(pdev, 0), ism);
        pci_free_irq_vectors(pdev);
}

static int ism_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
        struct dibs_dev *dibs;
        struct zpci_dev *zdev;
        struct ism_dev *ism;
        int ret;

        ism = kzalloc_obj(*ism);
        if (!ism)
                return -ENOMEM;

        spin_lock_init(&ism->cmd_lock);
        dev_set_drvdata(&pdev->dev, ism);
        ism->pdev = pdev;

        ret = pci_enable_device_mem(pdev);
        if (ret)
                goto err_dev;

        ret = pci_request_mem_regions(pdev, DRV_NAME);
        if (ret)
                goto err_disable;

        ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
        if (ret)
                goto err_resource;

        dma_set_seg_boundary(&pdev->dev, SZ_1M - 1);
        dma_set_max_seg_size(&pdev->dev, SZ_1M);
        pci_set_master(pdev);

        dibs = dibs_dev_alloc();
        if (!dibs) {
                ret = -ENOMEM;
                goto err_resource;
        }
        /* set this up before we enable interrupts */
        ism->dibs = dibs;
        dibs->drv_priv = ism;
        dibs->ops = &ism_ops;

        /* enable ism device, but any interrupts and events will be ignored
         * before dibs_dev_add() adds it to any clients.
         */
        ret = ism_dev_init(ism);
        if (ret)
                goto err_dibs;

        /* after ism_dev_init() we can call ism function to set gid */
        ret = ism_read_local_gid(dibs);
        if (ret)
                goto err_ism;

        dibs->dev.parent = &pdev->dev;

        zdev = to_zpci(pdev);
        dev_set_name(&dibs->dev, "ism%x", zdev->uid ? zdev->uid : zdev->fid);

        ret = dibs_dev_add(dibs);
        if (ret)
                goto err_ism;

        return 0;

err_ism:
        ism_dev_exit(ism);
err_dibs:
        /* pairs with dibs_dev_alloc() */
        put_device(&dibs->dev);
err_resource:
        pci_release_mem_regions(pdev);
err_disable:
        pci_disable_device(pdev);
err_dev:
        dev_set_drvdata(&pdev->dev, NULL);
        kfree(ism);

        return ret;
}

static void ism_remove(struct pci_dev *pdev)
{
        struct ism_dev *ism = dev_get_drvdata(&pdev->dev);
        struct dibs_dev *dibs = ism->dibs;

        dibs_dev_del(dibs);
        ism_dev_exit(ism);
        /* pairs with dibs_dev_alloc() */
        put_device(&dibs->dev);

        pci_release_mem_regions(pdev);
        pci_disable_device(pdev);
        dev_set_drvdata(&pdev->dev, NULL);
        kfree(ism);
}

static struct pci_driver ism_driver = {
        .name     = DRV_NAME,
        .id_table = ism_device_table,
        .probe    = ism_probe,
        .remove   = ism_remove,
};

static int __init ism_init(void)
{
        int ret;

        ism_debug_info = debug_register("ism", 2, 1, 16);
        if (!ism_debug_info)
                return -ENODEV;

        debug_register_view(ism_debug_info, &debug_hex_ascii_view);
        ret = pci_register_driver(&ism_driver);
        if (ret)
                debug_unregister(ism_debug_info);

        return ret;
}

static void __exit ism_exit(void)
{
        pci_unregister_driver(&ism_driver);
        debug_unregister(ism_debug_info);
}

module_init(ism_init);
module_exit(ism_exit);