// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright IBM Corp. 2012
 *
 * Author(s):
 *   Jan Glauber <jang@linux.vnet.ibm.com>
 */

#define pr_fmt(fmt) "zpci: " fmt

#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/pci.h>
#include <linux/uaccess.h>
#include <asm/asm-extable.h>
#include <asm/pci_debug.h>
#include <asm/pci_clp.h>
#include <asm/asm.h>
#include <asm/clp.h>
#include <uapi/asm/clp.h>

#include "pci_bus.h"

bool zpci_unique_uid;

void update_uid_checking(bool new)
{
        if (zpci_unique_uid != new)
                zpci_dbg(3, "uid checking:%d\n", new);

        zpci_unique_uid = new;
}

static inline void zpci_err_clp(unsigned int rsp, int rc)
{
        struct {
                unsigned int rsp;
                int rc;
        } __packed data = {rsp, rc};

        zpci_err_hex(&data, sizeof(data));
}

/*
 * Call Logical Processor with c=1, lps=0 and command 1
 * to get the bit mask of installed logical processors
 */
static inline int clp_get_ilp(unsigned long *ilp)
{
        unsigned long mask;
        int cc, exception;

        exception = 1;
        asm_inline volatile (
                "       .insn   rrf,0xb9a00000,%[mask],%[cmd],8,0\n"
                "0:     lhi     %[exc],0\n"
                "1:\n"
                CC_IPM(cc)
                EX_TABLE(0b, 1b)
                : CC_OUT(cc, cc), [mask] "=d" (mask), [exc] "+d" (exception)
                : [cmd] "a" (1)
                : CC_CLOBBER);
        *ilp = mask;
        return exception ? 3 : CC_TRANSFORM(cc);
}

/*
 * Call Logical Processor with c=0, the give constant lps and an lpcb request.
 */
static __always_inline int clp_req(void *data, unsigned int lps)
{
        struct { u8 _[CLP_BLK_SIZE]; } *req = data;
        int cc, exception;
        u64 ignored;

        exception = 1;
        asm_inline volatile (
                "       .insn   rrf,0xb9a00000,%[ign],%[req],0,%[lps]\n"
                "0:     lhi     %[exc],0\n"
                "1:\n"
                CC_IPM(cc)
                EX_TABLE(0b, 1b)
                : CC_OUT(cc, cc), [ign] "=d" (ignored), "+m" (*req), [exc] "+d" (exception)
                : [req] "a" (req), [lps] "i" (lps)
                : CC_CLOBBER);
        return exception ? 3 : CC_TRANSFORM(cc);
}

static void *clp_alloc_block(gfp_t gfp_mask)
{
        return (void *) __get_free_pages(gfp_mask, get_order(CLP_BLK_SIZE));
}

static void clp_free_block(void *ptr)
{
        free_pages((unsigned long) ptr, get_order(CLP_BLK_SIZE));
}

static void clp_store_query_pci_fngrp(struct zpci_dev *zdev,
                                      struct clp_rsp_query_pci_grp *response)
{
        zdev->tlb_refresh = response->refresh;
        zdev->dma_mask = response->dasm;
        zdev->msi_addr = response->msia;
        zdev->max_msi = response->noi;
        zdev->fmb_update = response->mui;
        zdev->version = response->version;
        zdev->maxstbl = response->maxstbl;
        zdev->dtsm = response->dtsm;
        zdev->rtr_avail = response->rtr;

        switch (response->version) {
        case 1:
                zdev->max_bus_speed = PCIE_SPEED_5_0GT;
                break;
        default:
                zdev->max_bus_speed = PCI_SPEED_UNKNOWN;
                break;
        }
}

static int clp_query_pci_fngrp(struct zpci_dev *zdev, u8 pfgid)
{
        struct clp_req_rsp_query_pci_grp *rrb;
        int rc;

        rrb = clp_alloc_block(GFP_KERNEL);
        if (!rrb)
                return -ENOMEM;

        memset(rrb, 0, sizeof(*rrb));
        rrb->request.hdr.len = sizeof(rrb->request);
        rrb->request.hdr.cmd = CLP_QUERY_PCI_FNGRP;
        rrb->response.hdr.len = sizeof(rrb->response);
        rrb->request.pfgid = pfgid;

        rc = clp_req(rrb, CLP_LPS_PCI);
        if (!rc && rrb->response.hdr.rsp == CLP_RC_OK)
                clp_store_query_pci_fngrp(zdev, &rrb->response);
        else {
                zpci_err("Q PCI FGRP:\n");
                zpci_err_clp(rrb->response.hdr.rsp, rc);
                rc = -EIO;
        }
        clp_free_block(rrb);
        return rc;
}

static int clp_store_query_pci_fn(struct zpci_dev *zdev,
                                  struct clp_rsp_query_pci *response)
{
        int i;

        for (i = 0; i < PCI_STD_NUM_BARS; i++) {
                zdev->bars[i].val = le32_to_cpu(response->bar[i]);
                zdev->bars[i].size = response->bar_size[i];
        }
        zdev->start_dma = response->sdma;
        zdev->end_dma = response->edma;
        zdev->pchid = response->pchid;
        zdev->pfgid = response->pfgid;
        zdev->pft = response->pft;
        zdev->vfn = response->vfn;
        zdev->port = response->port;
        zdev->fidparm = response->fidparm;
        zdev->uid = response->uid;
        zdev->fmb_length = sizeof(u32) * response->fmb_len;
        zdev->is_physfn = response->is_physfn;
        zdev->rid_available = response->rid_avail;
        if (zdev->rid_available)
                zdev->rid = response->rid;
        zdev->tid_avail = response->tid_avail;
        if (zdev->tid_avail)
                zdev->tid = response->tid;

        memcpy(zdev->pfip, response->pfip, sizeof(zdev->pfip));
        if (response->util_str_avail) {
                memcpy(zdev->util_str, response->util_str,
                       sizeof(zdev->util_str));
                zdev->util_str_avail = 1;
        }
        zdev->mio_capable = response->mio_addr_avail;
        for (i = 0; i < PCI_STD_NUM_BARS; i++) {
                if (!(response->mio.valid & (1 << (PCI_STD_NUM_BARS - i - 1))))
                        continue;

                zdev->bars[i].mio_wb = (void __iomem *) response->mio.addr[i].wb;
                zdev->bars[i].mio_wt = (void __iomem *) response->mio.addr[i].wt;
        }
        return 0;
}

int clp_query_pci_fn(struct zpci_dev *zdev)
{
        struct clp_req_rsp_query_pci *rrb;
        int rc;

        rrb = clp_alloc_block(GFP_KERNEL);
        if (!rrb)
                return -ENOMEM;

        memset(rrb, 0, sizeof(*rrb));
        rrb->request.hdr.len = sizeof(rrb->request);
        rrb->request.hdr.cmd = CLP_QUERY_PCI_FN;
        rrb->response.hdr.len = sizeof(rrb->response);
        rrb->request.fh = zdev->fh;

        rc = clp_req(rrb, CLP_LPS_PCI);
        if (!rc && rrb->response.hdr.rsp == CLP_RC_OK) {
                rc = clp_store_query_pci_fn(zdev, &rrb->response);
                if (rc)
                        goto out;
                rc = clp_query_pci_fngrp(zdev, rrb->response.pfgid);
        } else {
                zpci_err("Q PCI FN:\n");
                zpci_err_clp(rrb->response.hdr.rsp, rc);
                rc = -EIO;
        }
out:
        clp_free_block(rrb);
        return rc;
}

/**
 * clp_set_pci_fn() - Execute a command on a PCI function
 * @zdev: Function that will be affected
 * @fh: Out parameter for updated function handle
 * @nr_dma_as: DMA address space number
 * @command: The command code to execute
 *
 * Returns: 0 on success, < 0 for Linux errors (e.g. -ENOMEM), and
 * > 0 for non-success platform responses
 */
static int clp_set_pci_fn(struct zpci_dev *zdev, u32 *fh, u8 nr_dma_as, u8 command)
{
        struct clp_req_rsp_set_pci *rrb;
        int rc, retries = 100;
        u32 gisa = 0;

        *fh = 0;
        rrb = clp_alloc_block(GFP_KERNEL);
        if (!rrb)
                return -ENOMEM;

        if (command != CLP_SET_DISABLE_PCI_FN)
                gisa = zdev->gisa;

        do {
                memset(rrb, 0, sizeof(*rrb));
                rrb->request.hdr.len = sizeof(rrb->request);
                rrb->request.hdr.cmd = CLP_SET_PCI_FN;
                rrb->response.hdr.len = sizeof(rrb->response);
                rrb->request.fh = zdev->fh;
                rrb->request.oc = command;
                rrb->request.ndas = nr_dma_as;
                rrb->request.gisa = gisa;

                rc = clp_req(rrb, CLP_LPS_PCI);
                if (rrb->response.hdr.rsp == CLP_RC_SETPCIFN_BUSY) {
                        retries--;
                        if (retries < 0)
                                break;
                        msleep(20);
                }
        } while (rrb->response.hdr.rsp == CLP_RC_SETPCIFN_BUSY);

        if (!rc && rrb->response.hdr.rsp == CLP_RC_OK) {
                *fh = rrb->response.fh;
        } else {
                zpci_err("Set PCI FN:\n");
                zpci_err_clp(rrb->response.hdr.rsp, rc);
                if (!rc)
                        rc = rrb->response.hdr.rsp;
        }
        clp_free_block(rrb);
        return rc;
}

int clp_setup_writeback_mio(void)
{
        struct clp_req_rsp_slpc_pci *rrb;
        u8  wb_bit_pos;
        int rc;

        rrb = clp_alloc_block(GFP_KERNEL);
        if (!rrb)
                return -ENOMEM;

        memset(rrb, 0, sizeof(*rrb));
        rrb->request.hdr.len = sizeof(rrb->request);
        rrb->request.hdr.cmd = CLP_SLPC;
        rrb->response.hdr.len = sizeof(rrb->response);

        rc = clp_req(rrb, CLP_LPS_PCI);
        if (!rc && rrb->response.hdr.rsp == CLP_RC_OK) {
                if (rrb->response.vwb) {
                        wb_bit_pos = rrb->response.mio_wb;
                        set_bit_inv(wb_bit_pos, &mio_wb_bit_mask);
                        zpci_dbg(3, "wb bit: %d\n", wb_bit_pos);
                } else {
                        zpci_dbg(3, "wb bit: n.a.\n");
                }

        } else {
                zpci_err("SLPC PCI:\n");
                zpci_err_clp(rrb->response.hdr.rsp, rc);
                rc = -EIO;
        }
        clp_free_block(rrb);
        return rc;
}

int clp_enable_fh(struct zpci_dev *zdev, u32 *fh, u8 nr_dma_as)
{
        int rc;

        rc = clp_set_pci_fn(zdev, fh, nr_dma_as, CLP_SET_ENABLE_PCI_FN);
        zpci_dbg(3, "ena fid:%x, fh:%x, rc:%d\n", zdev->fid, *fh, rc);
        if (!rc && zpci_use_mio(zdev)) {
                rc = clp_set_pci_fn(zdev, fh, nr_dma_as, CLP_SET_ENABLE_MIO);
                zpci_dbg(3, "ena mio fid:%x, fh:%x, rc:%d\n",
                                zdev->fid, *fh, rc);
                if (rc)
                        clp_disable_fh(zdev, fh);
        }
        return rc;
}

int clp_disable_fh(struct zpci_dev *zdev, u32 *fh)
{
        int rc;

        if (!zdev_enabled(zdev))
                return 0;

        rc = clp_set_pci_fn(zdev, fh, 0, CLP_SET_DISABLE_PCI_FN);
        zpci_dbg(3, "dis fid:%x, fh:%x, rc:%d\n", zdev->fid, *fh, rc);
        return rc;
}

static int clp_list_pci_req(struct clp_req_rsp_list_pci *rrb,
                            u64 *resume_token, int *nentries)
{
        int rc;

        memset(rrb, 0, sizeof(*rrb));
        rrb->request.hdr.len = sizeof(rrb->request);
        rrb->request.hdr.cmd = CLP_LIST_PCI;
        /* store as many entries as possible */
        rrb->response.hdr.len = CLP_BLK_SIZE - LIST_PCI_HDR_LEN;
        rrb->request.resume_token = *resume_token;

        /* Get PCI function handle list */
        rc = clp_req(rrb, CLP_LPS_PCI);
        if (rc || rrb->response.hdr.rsp != CLP_RC_OK) {
                zpci_err("List PCI FN:\n");
                zpci_err_clp(rrb->response.hdr.rsp, rc);
                return -EIO;
        }

        update_uid_checking(rrb->response.uid_checking);
        WARN_ON_ONCE(rrb->response.entry_size !=
                sizeof(struct clp_fh_list_entry));

        *nentries = (rrb->response.hdr.len - LIST_PCI_HDR_LEN) /
                rrb->response.entry_size;
        *resume_token = rrb->response.resume_token;

        return rc;
}

static int clp_list_pci(struct clp_req_rsp_list_pci *rrb, void *data,
                        void (*cb)(struct clp_fh_list_entry *, void *))
{
        u64 resume_token = 0;
        int nentries, i, rc;

        do {
                rc = clp_list_pci_req(rrb, &resume_token, &nentries);
                if (rc)
                        return rc;
                for (i = 0; i < nentries; i++)
                        cb(&rrb->response.fh_list[i], data);
        } while (resume_token);

        return rc;
}

static int clp_find_pci(struct clp_req_rsp_list_pci *rrb, u32 fid,
                        struct clp_fh_list_entry *entry)
{
        struct clp_fh_list_entry *fh_list;
        u64 resume_token = 0;
        int nentries, i, rc;

        do {
                rc = clp_list_pci_req(rrb, &resume_token, &nentries);
                if (rc)
                        return rc;
                fh_list = rrb->response.fh_list;
                for (i = 0; i < nentries; i++) {
                        if (fh_list[i].fid == fid) {
                                *entry = fh_list[i];
                                return 0;
                        }
                }
        } while (resume_token);

        return -ENODEV;
}

static void __clp_add(struct clp_fh_list_entry *entry, void *data)
{
        struct list_head *scan_list = data;
        struct zpci_dev *zdev;

        if (!entry->vendor_id)
                return;

        zdev = get_zdev_by_fid(entry->fid);
        if (zdev) {
                zpci_zdev_put(zdev);
                return;
        }
        zdev = zpci_create_device(entry->fid, entry->fh, entry->config_state);
        if (IS_ERR(zdev))
                return;
        list_add_tail(&zdev->entry, scan_list);
}

int clp_scan_pci_devices(struct list_head *scan_list)
{
        struct clp_req_rsp_list_pci *rrb;
        int rc;

        rrb = clp_alloc_block(GFP_KERNEL);
        if (!rrb)
                return -ENOMEM;

        rc = clp_list_pci(rrb, scan_list, __clp_add);

        clp_free_block(rrb);
        return rc;
}

/*
 * Get the current function handle of the function matching @fid
 */
int clp_refresh_fh(u32 fid, u32 *fh)
{
        struct clp_req_rsp_list_pci *rrb;
        struct clp_fh_list_entry entry;
        int rc;

        rrb = clp_alloc_block(GFP_NOWAIT);
        if (!rrb)
                return -ENOMEM;

        rc = clp_find_pci(rrb, fid, &entry);
        if (!rc)
                *fh = entry.fh;

        clp_free_block(rrb);
        return rc;
}

int clp_get_state(u32 fid, enum zpci_state *state)
{
        struct clp_req_rsp_list_pci *rrb;
        struct clp_fh_list_entry entry;
        int rc;

        rrb = clp_alloc_block(GFP_ATOMIC);
        if (!rrb)
                return -ENOMEM;

        rc = clp_find_pci(rrb, fid, &entry);
        if (!rc) {
                *state = entry.config_state;
        } else if (rc == -ENODEV) {
                *state = ZPCI_FN_STATE_RESERVED;
                rc = 0;
        }

        clp_free_block(rrb);
        return rc;
}

static int clp_base_slpc(struct clp_req *req, struct clp_req_rsp_slpc *lpcb)
{
        unsigned long limit = PAGE_SIZE - sizeof(lpcb->request);

        if (lpcb->request.hdr.len != sizeof(lpcb->request) ||
            lpcb->response.hdr.len > limit)
                return -EINVAL;
        return clp_req(lpcb, CLP_LPS_BASE) ? -EOPNOTSUPP : 0;
}

static int clp_base_command(struct clp_req *req, struct clp_req_hdr *lpcb)
{
        switch (lpcb->cmd) {
        case 0x0001: /* store logical-processor characteristics */
                return clp_base_slpc(req, (void *) lpcb);
        default:
                return -EINVAL;
        }
}

static int clp_pci_slpc(struct clp_req *req, struct clp_req_rsp_slpc_pci *lpcb)
{
        unsigned long limit = PAGE_SIZE - sizeof(lpcb->request);

        if (lpcb->request.hdr.len != sizeof(lpcb->request) ||
            lpcb->response.hdr.len > limit)
                return -EINVAL;
        return clp_req(lpcb, CLP_LPS_PCI) ? -EOPNOTSUPP : 0;
}

static int clp_pci_list(struct clp_req *req, struct clp_req_rsp_list_pci *lpcb)
{
        unsigned long limit = PAGE_SIZE - sizeof(lpcb->request);

        if (lpcb->request.hdr.len != sizeof(lpcb->request) ||
            lpcb->response.hdr.len > limit)
                return -EINVAL;
        if (lpcb->request.reserved2 != 0)
                return -EINVAL;
        return clp_req(lpcb, CLP_LPS_PCI) ? -EOPNOTSUPP : 0;
}

static int clp_pci_query(struct clp_req *req,
                         struct clp_req_rsp_query_pci *lpcb)
{
        unsigned long limit = PAGE_SIZE - sizeof(lpcb->request);

        if (lpcb->request.hdr.len != sizeof(lpcb->request) ||
            lpcb->response.hdr.len > limit)
                return -EINVAL;
        if (lpcb->request.reserved2 != 0 || lpcb->request.reserved3 != 0)
                return -EINVAL;
        return clp_req(lpcb, CLP_LPS_PCI) ? -EOPNOTSUPP : 0;
}

static int clp_pci_query_grp(struct clp_req *req,
                             struct clp_req_rsp_query_pci_grp *lpcb)
{
        unsigned long limit = PAGE_SIZE - sizeof(lpcb->request);

        if (lpcb->request.hdr.len != sizeof(lpcb->request) ||
            lpcb->response.hdr.len > limit)
                return -EINVAL;
        if (lpcb->request.reserved2 != 0 || lpcb->request.reserved3 != 0 ||
            lpcb->request.reserved4 != 0)
                return -EINVAL;
        return clp_req(lpcb, CLP_LPS_PCI) ? -EOPNOTSUPP : 0;
}

static int clp_pci_command(struct clp_req *req, struct clp_req_hdr *lpcb)
{
        switch (lpcb->cmd) {
        case 0x0001: /* store logical-processor characteristics */
                return clp_pci_slpc(req, (void *) lpcb);
        case 0x0002: /* list PCI functions */
                return clp_pci_list(req, (void *) lpcb);
        case 0x0003: /* query PCI function */
                return clp_pci_query(req, (void *) lpcb);
        case 0x0004: /* query PCI function group */
                return clp_pci_query_grp(req, (void *) lpcb);
        default:
                return -EINVAL;
        }
}

static int clp_normal_command(struct clp_req *req)
{
        struct clp_req_hdr *lpcb;
        void __user *uptr;
        int rc;

        rc = -EINVAL;
        if (req->lps != 0 && req->lps != 2)
                goto out;

        rc = -ENOMEM;
        lpcb = clp_alloc_block(GFP_KERNEL);
        if (!lpcb)
                goto out;

        rc = -EFAULT;
        uptr = (void __force __user *)(unsigned long) req->data_p;
        if (copy_from_user(lpcb, uptr, PAGE_SIZE) != 0)
                goto out_free;

        rc = -EINVAL;
        if (lpcb->fmt != 0 || lpcb->reserved1 != 0 || lpcb->reserved2 != 0)
                goto out_free;

        switch (req->lps) {
        case 0:
                rc = clp_base_command(req, lpcb);
                break;
        case 2:
                rc = clp_pci_command(req, lpcb);
                break;
        }
        if (rc)
                goto out_free;

        rc = -EFAULT;
        if (copy_to_user(uptr, lpcb, PAGE_SIZE) != 0)
                goto out_free;

        rc = 0;

out_free:
        clp_free_block(lpcb);
out:
        return rc;
}

static int clp_immediate_command(struct clp_req *req)
{
        void __user *uptr;
        unsigned long ilp;
        int exists;

        if (req->cmd > 1 || clp_get_ilp(&ilp) != 0)
                return -EINVAL;

        uptr = (void __force __user *)(unsigned long) req->data_p;
        if (req->cmd == 0) {
                /* Command code 0: test for a specific processor */
                exists = test_bit_inv(req->lps, &ilp);
                return put_user(exists, (int __user *) uptr);
        }
        /* Command code 1: return bit mask of installed processors */
        return put_user(ilp, (unsigned long __user *) uptr);
}

static long clp_misc_ioctl(struct file *filp, unsigned int cmd,
                           unsigned long arg)
{
        struct clp_req req;
        void __user *argp;

        if (cmd != CLP_SYNC)
                return -EINVAL;

        argp = (void __user *)arg;
        if (copy_from_user(&req, argp, sizeof(req)))
                return -EFAULT;
        if (req.r != 0)
                return -EINVAL;
        return req.c ? clp_immediate_command(&req) : clp_normal_command(&req);
}

static int clp_misc_release(struct inode *inode, struct file *filp)
{
        return 0;
}

static const struct file_operations clp_misc_fops = {
        .owner = THIS_MODULE,
        .open = nonseekable_open,
        .release = clp_misc_release,
        .unlocked_ioctl = clp_misc_ioctl,
};

static struct miscdevice clp_misc_device = {
        .minor = MISC_DYNAMIC_MINOR,
        .name = "clp",
        .fops = &clp_misc_fops,
};

builtin_misc_device(clp_misc_device);