/*
 * CXL Flash Device Driver
 *
 * Written by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>, IBM Corporation
 *             Uma Krishnan <ukrishn@linux.vnet.ibm.com>, IBM Corporation
 *
 * Copyright (C) 2018 IBM Corporation
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/file.h>
#include <linux/idr.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/poll.h>
#include <linux/sched/signal.h>

#include <misc/ocxl.h>

#include <uapi/misc/cxl.h>

#include "backend.h"
#include "ocxl_hw.h"

/*
 * Pseudo-filesystem to allocate inodes.
 */

#define OCXLFLASH_FS_MAGIC      0x1697698f

static int ocxlflash_fs_cnt;
static struct vfsmount *ocxlflash_vfs_mount;

static const struct dentry_operations ocxlflash_fs_dops = {
        .d_dname        = simple_dname,
};

/*
 * ocxlflash_fs_mount() - mount the pseudo-filesystem
 * @fs_type:    File system type.
 * @flags:      Flags for the filesystem.
 * @dev_name:   Device name associated with the filesystem.
 * @data:       Data pointer.
 *
 * Return: pointer to the directory entry structure
 */
static struct dentry *ocxlflash_fs_mount(struct file_system_type *fs_type,
                                         int flags, const char *dev_name,
                                         void *data)
{
        return mount_pseudo(fs_type, "ocxlflash:", NULL, &ocxlflash_fs_dops,
                            OCXLFLASH_FS_MAGIC);
}

static struct file_system_type ocxlflash_fs_type = {
        .name           = "ocxlflash",
        .owner          = THIS_MODULE,
        .mount          = ocxlflash_fs_mount,
        .kill_sb        = kill_anon_super,
};

/*
 * ocxlflash_release_mapping() - release the memory mapping
 * @ctx:        Context whose mapping is to be released.
 */
static void ocxlflash_release_mapping(struct ocxlflash_context *ctx)
{
        if (ctx->mapping)
                simple_release_fs(&ocxlflash_vfs_mount, &ocxlflash_fs_cnt);
        ctx->mapping = NULL;
}

/*
 * ocxlflash_getfile() - allocate pseudo filesystem, inode, and the file
 * @dev:        Generic device of the host.
 * @name:       Name of the pseudo filesystem.
 * @fops:       File operations.
 * @priv:       Private data.
 * @flags:      Flags for the file.
 *
 * Return: pointer to the file on success, ERR_PTR on failure
 */
static struct file *ocxlflash_getfile(struct device *dev, const char *name,
                                      const struct file_operations *fops,
                                      void *priv, int flags)
{
        struct file *file;
        struct inode *inode;
        int rc;

        if (fops->owner && !try_module_get(fops->owner)) {
                dev_err(dev, "%s: Owner does not exist\n", __func__);
                rc = -ENOENT;
                goto err1;
        }

        rc = simple_pin_fs(&ocxlflash_fs_type, &ocxlflash_vfs_mount,
                           &ocxlflash_fs_cnt);
        if (unlikely(rc < 0)) {
                dev_err(dev, "%s: Cannot mount ocxlflash pseudofs rc=%d\n",
                        __func__, rc);
                goto err2;
        }

        inode = alloc_anon_inode(ocxlflash_vfs_mount->mnt_sb);
        if (IS_ERR(inode)) {
                rc = PTR_ERR(inode);
                dev_err(dev, "%s: alloc_anon_inode failed rc=%d\n",
                        __func__, rc);
                goto err3;
        }

        file = alloc_file_pseudo(inode, ocxlflash_vfs_mount, name,
                                 flags & (O_ACCMODE | O_NONBLOCK), fops);
        if (IS_ERR(file)) {
                rc = PTR_ERR(file);
                dev_err(dev, "%s: alloc_file failed rc=%d\n",
                        __func__, rc);
                goto err4;
        }

        file->private_data = priv;
out:
        return file;
err4:
        iput(inode);
err3:
        simple_release_fs(&ocxlflash_vfs_mount, &ocxlflash_fs_cnt);
err2:
        module_put(fops->owner);
err1:
        file = ERR_PTR(rc);
        goto out;
}

/**
 * ocxlflash_psa_map() - map the process specific MMIO space
 * @ctx_cookie: Adapter context for which the mapping needs to be done.
 *
 * Return: MMIO pointer of the mapped region
 */
static void __iomem *ocxlflash_psa_map(void *ctx_cookie)
{
        struct ocxlflash_context *ctx = ctx_cookie;
        struct device *dev = ctx->hw_afu->dev;

        mutex_lock(&ctx->state_mutex);
        if (ctx->state != STARTED) {
                dev_err(dev, "%s: Context not started, state=%d\n", __func__,
                        ctx->state);
                mutex_unlock(&ctx->state_mutex);
                return NULL;
        }
        mutex_unlock(&ctx->state_mutex);

        return ioremap(ctx->psn_phys, ctx->psn_size);
}

/**
 * ocxlflash_psa_unmap() - unmap the process specific MMIO space
 * @addr:       MMIO pointer to unmap.
 */
static void ocxlflash_psa_unmap(void __iomem *addr)
{
        iounmap(addr);
}

/**
 * ocxlflash_process_element() - get process element of the adapter context
 * @ctx_cookie: Adapter context associated with the process element.
 *
 * Return: process element of the adapter context
 */
static int ocxlflash_process_element(void *ctx_cookie)
{
        struct ocxlflash_context *ctx = ctx_cookie;

        return ctx->pe;
}

/**
 * afu_map_irq() - map the interrupt of the adapter context
 * @flags:      Flags.
 * @ctx:        Adapter context.
 * @num:        Per-context AFU interrupt number.
 * @handler:    Interrupt handler to register.
 * @cookie:     Interrupt handler private data.
 * @name:       Name of the interrupt.
 *
 * Return: 0 on success, -errno on failure
 */
static int afu_map_irq(u64 flags, struct ocxlflash_context *ctx, int num,
                       irq_handler_t handler, void *cookie, char *name)
{
        struct ocxl_hw_afu *afu = ctx->hw_afu;
        struct device *dev = afu->dev;
        struct ocxlflash_irqs *irq;
        void __iomem *vtrig;
        u32 virq;
        int rc = 0;

        if (num < 0 || num >= ctx->num_irqs) {
                dev_err(dev, "%s: Interrupt %d not allocated\n", __func__, num);
                rc = -ENOENT;
                goto out;
        }

        irq = &ctx->irqs[num];
        virq = irq_create_mapping(NULL, irq->hwirq);
        if (unlikely(!virq)) {
                dev_err(dev, "%s: irq_create_mapping failed\n", __func__);
                rc = -ENOMEM;
                goto out;
        }

        rc = request_irq(virq, handler, 0, name, cookie);
        if (unlikely(rc)) {
                dev_err(dev, "%s: request_irq failed rc=%d\n", __func__, rc);
                goto err1;
        }

        vtrig = ioremap(irq->ptrig, PAGE_SIZE);
        if (unlikely(!vtrig)) {
                dev_err(dev, "%s: Trigger page mapping failed\n", __func__);
                rc = -ENOMEM;
                goto err2;
        }

        irq->virq = virq;
        irq->vtrig = vtrig;
out:
        return rc;
err2:
        free_irq(virq, cookie);
err1:
        irq_dispose_mapping(virq);
        goto out;
}

/**
 * ocxlflash_map_afu_irq() - map the interrupt of the adapter context
 * @ctx_cookie: Adapter context.
 * @num:        Per-context AFU interrupt number.
 * @handler:    Interrupt handler to register.
 * @cookie:     Interrupt handler private data.
 * @name:       Name of the interrupt.
 *
 * Return: 0 on success, -errno on failure
 */
static int ocxlflash_map_afu_irq(void *ctx_cookie, int num,
                                 irq_handler_t handler, void *cookie,
                                 char *name)
{
        return afu_map_irq(0, ctx_cookie, num, handler, cookie, name);
}

/**
 * afu_unmap_irq() - unmap the interrupt
 * @flags:      Flags.
 * @ctx:        Adapter context.
 * @num:        Per-context AFU interrupt number.
 * @cookie:     Interrupt handler private data.
 */
static void afu_unmap_irq(u64 flags, struct ocxlflash_context *ctx, int num,
                          void *cookie)
{
        struct ocxl_hw_afu *afu = ctx->hw_afu;
        struct device *dev = afu->dev;
        struct ocxlflash_irqs *irq;

        if (num < 0 || num >= ctx->num_irqs) {
                dev_err(dev, "%s: Interrupt %d not allocated\n", __func__, num);
                return;
        }

        irq = &ctx->irqs[num];
        if (irq->vtrig)
                iounmap(irq->vtrig);

        if (irq_find_mapping(NULL, irq->hwirq)) {
                free_irq(irq->virq, cookie);
                irq_dispose_mapping(irq->virq);
        }

        memset(irq, 0, sizeof(*irq));
}

/**
 * ocxlflash_unmap_afu_irq() - unmap the interrupt
 * @ctx_cookie: Adapter context.
 * @num:        Per-context AFU interrupt number.
 * @cookie:     Interrupt handler private data.
 */
static void ocxlflash_unmap_afu_irq(void *ctx_cookie, int num, void *cookie)
{
        return afu_unmap_irq(0, ctx_cookie, num, cookie);
}

/**
 * ocxlflash_get_irq_objhndl() - get the object handle for an interrupt
 * @ctx_cookie: Context associated with the interrupt.
 * @irq:        Interrupt number.
 *
 * Return: effective address of the mapped region
 */
static u64 ocxlflash_get_irq_objhndl(void *ctx_cookie, int irq)
{
        struct ocxlflash_context *ctx = ctx_cookie;

        if (irq < 0 || irq >= ctx->num_irqs)
                return 0;

        return (__force u64)ctx->irqs[irq].vtrig;
}

/**
 * ocxlflash_xsl_fault() - callback when translation error is triggered
 * @data:       Private data provided at callback registration, the context.
 * @addr:       Address that triggered the error.
 * @dsisr:      Value of dsisr register.
 */
static void ocxlflash_xsl_fault(void *data, u64 addr, u64 dsisr)
{
        struct ocxlflash_context *ctx = data;

        spin_lock(&ctx->slock);
        ctx->fault_addr = addr;
        ctx->fault_dsisr = dsisr;
        ctx->pending_fault = true;
        spin_unlock(&ctx->slock);

        wake_up_all(&ctx->wq);
}

/**
 * start_context() - local routine to start a context
 * @ctx:        Adapter context to be started.
 *
 * Assign the context specific MMIO space, add and enable the PE.
 *
 * Return: 0 on success, -errno on failure
 */
static int start_context(struct ocxlflash_context *ctx)
{
        struct ocxl_hw_afu *afu = ctx->hw_afu;
        struct ocxl_afu_config *acfg = &afu->acfg;
        void *link_token = afu->link_token;
        struct device *dev = afu->dev;
        bool master = ctx->master;
        struct mm_struct *mm;
        int rc = 0;
        u32 pid;

        mutex_lock(&ctx->state_mutex);
        if (ctx->state != OPENED) {
                dev_err(dev, "%s: Context state invalid, state=%d\n",
                        __func__, ctx->state);
                rc = -EINVAL;
                goto out;
        }

        if (master) {
                ctx->psn_size = acfg->global_mmio_size;
                ctx->psn_phys = afu->gmmio_phys;
        } else {
                ctx->psn_size = acfg->pp_mmio_stride;
                ctx->psn_phys = afu->ppmmio_phys + (ctx->pe * ctx->psn_size);
        }

        /* pid and mm not set for master contexts */
        if (master) {
                pid = 0;
                mm = NULL;
        } else {
                pid = current->mm->context.id;
                mm = current->mm;
        }

        rc = ocxl_link_add_pe(link_token, ctx->pe, pid, 0, 0, mm,
                              ocxlflash_xsl_fault, ctx);
        if (unlikely(rc)) {
                dev_err(dev, "%s: ocxl_link_add_pe failed rc=%d\n",
                        __func__, rc);
                goto out;
        }

        ctx->state = STARTED;
out:
        mutex_unlock(&ctx->state_mutex);
        return rc;
}

/**
 * ocxlflash_start_context() - start a kernel context
 * @ctx_cookie: Adapter context to be started.
 *
 * Return: 0 on success, -errno on failure
 */
static int ocxlflash_start_context(void *ctx_cookie)
{
        struct ocxlflash_context *ctx = ctx_cookie;

        return start_context(ctx);
}

/**
 * ocxlflash_stop_context() - stop a context
 * @ctx_cookie: Adapter context to be stopped.
 *
 * Return: 0 on success, -errno on failure
 */
static int ocxlflash_stop_context(void *ctx_cookie)
{
        struct ocxlflash_context *ctx = ctx_cookie;
        struct ocxl_hw_afu *afu = ctx->hw_afu;
        struct ocxl_afu_config *acfg = &afu->acfg;
        struct pci_dev *pdev = afu->pdev;
        struct device *dev = afu->dev;
        enum ocxlflash_ctx_state state;
        int rc = 0;

        mutex_lock(&ctx->state_mutex);
        state = ctx->state;
        ctx->state = CLOSED;
        mutex_unlock(&ctx->state_mutex);
        if (state != STARTED)
                goto out;

        rc = ocxl_config_terminate_pasid(pdev, acfg->dvsec_afu_control_pos,
                                         ctx->pe);
        if (unlikely(rc)) {
                dev_err(dev, "%s: ocxl_config_terminate_pasid failed rc=%d\n",
                        __func__, rc);
                /* If EBUSY, PE could be referenced in future by the AFU */
                if (rc == -EBUSY)
                        goto out;
        }

        rc = ocxl_link_remove_pe(afu->link_token, ctx->pe);
        if (unlikely(rc)) {
                dev_err(dev, "%s: ocxl_link_remove_pe failed rc=%d\n",
                        __func__, rc);
                goto out;
        }
out:
        return rc;
}

/**
 * ocxlflash_afu_reset() - reset the AFU
 * @ctx_cookie: Adapter context.
 */
static int ocxlflash_afu_reset(void *ctx_cookie)
{
        struct ocxlflash_context *ctx = ctx_cookie;
        struct device *dev = ctx->hw_afu->dev;

        /* Pending implementation from OCXL transport services */
        dev_err_once(dev, "%s: afu_reset() fop not supported\n", __func__);

        /* Silently return success until it is implemented */
        return 0;
}

/**
 * ocxlflash_set_master() - sets the context as master
 * @ctx_cookie: Adapter context to set as master.
 */
static void ocxlflash_set_master(void *ctx_cookie)
{
        struct ocxlflash_context *ctx = ctx_cookie;

        ctx->master = true;
}

/**
 * ocxlflash_get_context() - obtains the context associated with the host
 * @pdev:       PCI device associated with the host.
 * @afu_cookie: Hardware AFU associated with the host.
 *
 * Return: returns the pointer to host adapter context
 */
static void *ocxlflash_get_context(struct pci_dev *pdev, void *afu_cookie)
{
        struct ocxl_hw_afu *afu = afu_cookie;

        return afu->ocxl_ctx;
}

/**
 * ocxlflash_dev_context_init() - allocate and initialize an adapter context
 * @pdev:       PCI device associated with the host.
 * @afu_cookie: Hardware AFU associated with the host.
 *
 * Return: returns the adapter context on success, ERR_PTR on failure
 */
static void *ocxlflash_dev_context_init(struct pci_dev *pdev, void *afu_cookie)
{
        struct ocxl_hw_afu *afu = afu_cookie;
        struct device *dev = afu->dev;
        struct ocxlflash_context *ctx;
        int rc;

        ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
        if (unlikely(!ctx)) {
                dev_err(dev, "%s: Context allocation failed\n", __func__);
                rc = -ENOMEM;
                goto err1;
        }

        idr_preload(GFP_KERNEL);
        rc = idr_alloc(&afu->idr, ctx, 0, afu->max_pasid, GFP_NOWAIT);
        idr_preload_end();
        if (unlikely(rc < 0)) {
                dev_err(dev, "%s: idr_alloc failed rc=%d\n", __func__, rc);
                goto err2;
        }

        spin_lock_init(&ctx->slock);
        init_waitqueue_head(&ctx->wq);
        mutex_init(&ctx->state_mutex);

        ctx->state = OPENED;
        ctx->pe = rc;
        ctx->master = false;
        ctx->mapping = NULL;
        ctx->hw_afu = afu;
        ctx->irq_bitmap = 0;
        ctx->pending_irq = false;
        ctx->pending_fault = false;
out:
        return ctx;
err2:
        kfree(ctx);
err1:
        ctx = ERR_PTR(rc);
        goto out;
}

/**
 * ocxlflash_release_context() - releases an adapter context
 * @ctx_cookie: Adapter context to be released.
 *
 * Return: 0 on success, -errno on failure
 */
static int ocxlflash_release_context(void *ctx_cookie)
{
        struct ocxlflash_context *ctx = ctx_cookie;
        struct device *dev;
        int rc = 0;

        if (!ctx)
                goto out;

        dev = ctx->hw_afu->dev;
        mutex_lock(&ctx->state_mutex);
        if (ctx->state >= STARTED) {
                dev_err(dev, "%s: Context in use, state=%d\n", __func__,
                        ctx->state);
                mutex_unlock(&ctx->state_mutex);
                rc = -EBUSY;
                goto out;
        }
        mutex_unlock(&ctx->state_mutex);

        idr_remove(&ctx->hw_afu->idr, ctx->pe);
        ocxlflash_release_mapping(ctx);
        kfree(ctx);
out:
        return rc;
}

/**
 * ocxlflash_perst_reloads_same_image() - sets the image reload policy
 * @afu_cookie: Hardware AFU associated with the host.
 * @image:      Whether to load the same image on PERST.
 */
static void ocxlflash_perst_reloads_same_image(void *afu_cookie, bool image)
{
        struct ocxl_hw_afu *afu = afu_cookie;

        afu->perst_same_image = image;
}

/**
 * ocxlflash_read_adapter_vpd() - reads the adapter VPD
 * @pdev:       PCI device associated with the host.
 * @buf:        Buffer to get the VPD data.
 * @count:      Size of buffer (maximum bytes that can be read).
 *
 * Return: size of VPD on success, -errno on failure
 */
static ssize_t ocxlflash_read_adapter_vpd(struct pci_dev *pdev, void *buf,
                                          size_t count)
{
        return pci_read_vpd(pdev, 0, count, buf);
}

/**
 * free_afu_irqs() - internal service to free interrupts
 * @ctx:        Adapter context.
 */
static void free_afu_irqs(struct ocxlflash_context *ctx)
{
        struct ocxl_hw_afu *afu = ctx->hw_afu;
        struct device *dev = afu->dev;
        int i;

        if (!ctx->irqs) {
                dev_err(dev, "%s: Interrupts not allocated\n", __func__);
                return;
        }

        for (i = ctx->num_irqs; i >= 0; i--)
                ocxl_link_free_irq(afu->link_token, ctx->irqs[i].hwirq);

        kfree(ctx->irqs);
        ctx->irqs = NULL;
}

/**
 * alloc_afu_irqs() - internal service to allocate interrupts
 * @ctx:        Context associated with the request.
 * @num:        Number of interrupts requested.
 *
 * Return: 0 on success, -errno on failure
 */
static int alloc_afu_irqs(struct ocxlflash_context *ctx, int num)
{
        struct ocxl_hw_afu *afu = ctx->hw_afu;
        struct device *dev = afu->dev;
        struct ocxlflash_irqs *irqs;
        u64 addr;
        int rc = 0;
        int hwirq;
        int i;

        if (ctx->irqs) {
                dev_err(dev, "%s: Interrupts already allocated\n", __func__);
                rc = -EEXIST;
                goto out;
        }

        if (num > OCXL_MAX_IRQS) {
                dev_err(dev, "%s: Too many interrupts num=%d\n", __func__, num);
                rc = -EINVAL;
                goto out;
        }

        irqs = kcalloc(num, sizeof(*irqs), GFP_KERNEL);
        if (unlikely(!irqs)) {
                dev_err(dev, "%s: Context irqs allocation failed\n", __func__);
                rc = -ENOMEM;
                goto out;
        }

        for (i = 0; i < num; i++) {
                rc = ocxl_link_irq_alloc(afu->link_token, &hwirq, &addr);
                if (unlikely(rc)) {
                        dev_err(dev, "%s: ocxl_link_irq_alloc failed rc=%d\n",
                                __func__, rc);
                        goto err;
                }

                irqs[i].hwirq = hwirq;
                irqs[i].ptrig = addr;
        }

        ctx->irqs = irqs;
        ctx->num_irqs = num;
out:
        return rc;
err:
        for (i = i-1; i >= 0; i--)
                ocxl_link_free_irq(afu->link_token, irqs[i].hwirq);
        kfree(irqs);
        goto out;
}

/**
 * ocxlflash_allocate_afu_irqs() - allocates the requested number of interrupts
 * @ctx_cookie: Context associated with the request.
 * @num:        Number of interrupts requested.
 *
 * Return: 0 on success, -errno on failure
 */
static int ocxlflash_allocate_afu_irqs(void *ctx_cookie, int num)
{
        return alloc_afu_irqs(ctx_cookie, num);
}

/**
 * ocxlflash_free_afu_irqs() - frees the interrupts of an adapter context
 * @ctx_cookie: Adapter context.
 */
static void ocxlflash_free_afu_irqs(void *ctx_cookie)
{
        free_afu_irqs(ctx_cookie);
}

/**
 * ocxlflash_unconfig_afu() - unconfigure the AFU
 * @afu: AFU associated with the host.
 */
static void ocxlflash_unconfig_afu(struct ocxl_hw_afu *afu)
{
        if (afu->gmmio_virt) {
                iounmap(afu->gmmio_virt);
                afu->gmmio_virt = NULL;
        }
}

/**
 * ocxlflash_destroy_afu() - destroy the AFU structure
 * @afu_cookie: AFU to be freed.
 */
static void ocxlflash_destroy_afu(void *afu_cookie)
{
        struct ocxl_hw_afu *afu = afu_cookie;
        int pos;

        if (!afu)
                return;

        ocxlflash_release_context(afu->ocxl_ctx);
        idr_destroy(&afu->idr);

        /* Disable the AFU */
        pos = afu->acfg.dvsec_afu_control_pos;
        ocxl_config_set_afu_state(afu->pdev, pos, 0);

        ocxlflash_unconfig_afu(afu);
        kfree(afu);
}

/**
 * ocxlflash_config_fn() - configure the host function
 * @pdev:       PCI device associated with the host.
 * @afu:        AFU associated with the host.
 *
 * Return: 0 on success, -errno on failure
 */
static int ocxlflash_config_fn(struct pci_dev *pdev, struct ocxl_hw_afu *afu)
{
        struct ocxl_fn_config *fcfg = &afu->fcfg;
        struct device *dev = &pdev->dev;
        u16 base, enabled, supported;
        int rc = 0;

        /* Read DVSEC config of the function */
        rc = ocxl_config_read_function(pdev, fcfg);
        if (unlikely(rc)) {
                dev_err(dev, "%s: ocxl_config_read_function failed rc=%d\n",
                        __func__, rc);
                goto out;
        }

        /* Check if function has AFUs defined, only 1 per function supported */
        if (fcfg->max_afu_index >= 0) {
                afu->is_present = true;
                if (fcfg->max_afu_index != 0)
                        dev_warn(dev, "%s: Unexpected AFU index value %d\n",
                                 __func__, fcfg->max_afu_index);
        }

        rc = ocxl_config_get_actag_info(pdev, &base, &enabled, &supported);
        if (unlikely(rc)) {
                dev_err(dev, "%s: ocxl_config_get_actag_info failed rc=%d\n",
                        __func__, rc);
                goto out;
        }

        afu->fn_actag_base = base;
        afu->fn_actag_enabled = enabled;

        ocxl_config_set_actag(pdev, fcfg->dvsec_function_pos, base, enabled);
        dev_dbg(dev, "%s: Function acTag range base=%u enabled=%u\n",
                __func__, base, enabled);

        rc = ocxl_link_setup(pdev, 0, &afu->link_token);
        if (unlikely(rc)) {
                dev_err(dev, "%s: ocxl_link_setup failed rc=%d\n",
                        __func__, rc);
                goto out;
        }

        rc = ocxl_config_set_TL(pdev, fcfg->dvsec_tl_pos);
        if (unlikely(rc)) {
                dev_err(dev, "%s: ocxl_config_set_TL failed rc=%d\n",
                        __func__, rc);
                goto err;
        }
out:
        return rc;
err:
        ocxl_link_release(pdev, afu->link_token);
        goto out;
}

/**
 * ocxlflash_unconfig_fn() - unconfigure the host function
 * @pdev:       PCI device associated with the host.
 * @afu:        AFU associated with the host.
 */
static void ocxlflash_unconfig_fn(struct pci_dev *pdev, struct ocxl_hw_afu *afu)
{
        ocxl_link_release(pdev, afu->link_token);
}

/**
 * ocxlflash_map_mmio() - map the AFU MMIO space
 * @afu: AFU associated with the host.
 *
 * Return: 0 on success, -errno on failure
 */
static int ocxlflash_map_mmio(struct ocxl_hw_afu *afu)
{
        struct ocxl_afu_config *acfg = &afu->acfg;
        struct pci_dev *pdev = afu->pdev;
        struct device *dev = afu->dev;
        phys_addr_t gmmio, ppmmio;
        int rc = 0;

        rc = pci_request_region(pdev, acfg->global_mmio_bar, "ocxlflash");
        if (unlikely(rc)) {
                dev_err(dev, "%s: pci_request_region for global failed rc=%d\n",
                        __func__, rc);
                goto out;
        }
        gmmio = pci_resource_start(pdev, acfg->global_mmio_bar);
        gmmio += acfg->global_mmio_offset;

        rc = pci_request_region(pdev, acfg->pp_mmio_bar, "ocxlflash");
        if (unlikely(rc)) {
                dev_err(dev, "%s: pci_request_region for pp bar failed rc=%d\n",
                        __func__, rc);
                goto err1;
        }
        ppmmio = pci_resource_start(pdev, acfg->pp_mmio_bar);
        ppmmio += acfg->pp_mmio_offset;

        afu->gmmio_virt = ioremap(gmmio, acfg->global_mmio_size);
        if (unlikely(!afu->gmmio_virt)) {
                dev_err(dev, "%s: MMIO mapping failed\n", __func__);
                rc = -ENOMEM;
                goto err2;
        }

        afu->gmmio_phys = gmmio;
        afu->ppmmio_phys = ppmmio;
out:
        return rc;
err2:
        pci_release_region(pdev, acfg->pp_mmio_bar);
err1:
        pci_release_region(pdev, acfg->global_mmio_bar);
        goto out;
}

/**
 * ocxlflash_config_afu() - configure the host AFU
 * @pdev:       PCI device associated with the host.
 * @afu:        AFU associated with the host.
 *
 * Must be called _after_ host function configuration.
 *
 * Return: 0 on success, -errno on failure
 */
static int ocxlflash_config_afu(struct pci_dev *pdev, struct ocxl_hw_afu *afu)
{
        struct ocxl_afu_config *acfg = &afu->acfg;
        struct ocxl_fn_config *fcfg = &afu->fcfg;
        struct device *dev = &pdev->dev;
        int count;
        int base;
        int pos;
        int rc = 0;

        /* This HW AFU function does not have any AFUs defined */
        if (!afu->is_present)
                goto out;

        /* Read AFU config at index 0 */
        rc = ocxl_config_read_afu(pdev, fcfg, acfg, 0);
        if (unlikely(rc)) {
                dev_err(dev, "%s: ocxl_config_read_afu failed rc=%d\n",
                        __func__, rc);
                goto out;
        }

        /* Only one AFU per function is supported, so actag_base is same */
        base = afu->fn_actag_base;
        count = min_t(int, acfg->actag_supported, afu->fn_actag_enabled);
        pos = acfg->dvsec_afu_control_pos;

        ocxl_config_set_afu_actag(pdev, pos, base, count);
        dev_dbg(dev, "%s: acTag base=%d enabled=%d\n", __func__, base, count);
        afu->afu_actag_base = base;
        afu->afu_actag_enabled = count;
        afu->max_pasid = 1 << acfg->pasid_supported_log;

        ocxl_config_set_afu_pasid(pdev, pos, 0, acfg->pasid_supported_log);

        rc = ocxlflash_map_mmio(afu);
        if (unlikely(rc)) {
                dev_err(dev, "%s: ocxlflash_map_mmio failed rc=%d\n",
                        __func__, rc);
                goto out;
        }

        /* Enable the AFU */
        ocxl_config_set_afu_state(pdev, acfg->dvsec_afu_control_pos, 1);
out:
        return rc;
}

/**
 * ocxlflash_create_afu() - create the AFU for OCXL
 * @pdev:       PCI device associated with the host.
 *
 * Return: AFU on success, NULL on failure
 */
static void *ocxlflash_create_afu(struct pci_dev *pdev)
{
        struct device *dev = &pdev->dev;
        struct ocxlflash_context *ctx;
        struct ocxl_hw_afu *afu;
        int rc;

        afu = kzalloc(sizeof(*afu), GFP_KERNEL);
        if (unlikely(!afu)) {
                dev_err(dev, "%s: HW AFU allocation failed\n", __func__);
                goto out;
        }

        afu->pdev = pdev;
        afu->dev = dev;
        idr_init(&afu->idr);

        rc = ocxlflash_config_fn(pdev, afu);
        if (unlikely(rc)) {
                dev_err(dev, "%s: Function configuration failed rc=%d\n",
                        __func__, rc);
                goto err1;
        }

        rc = ocxlflash_config_afu(pdev, afu);
        if (unlikely(rc)) {
                dev_err(dev, "%s: AFU configuration failed rc=%d\n",
                        __func__, rc);
                goto err2;
        }

        ctx = ocxlflash_dev_context_init(pdev, afu);
        if (IS_ERR(ctx)) {
                rc = PTR_ERR(ctx);
                dev_err(dev, "%s: ocxlflash_dev_context_init failed rc=%d\n",
                        __func__, rc);
                goto err3;
        }

        afu->ocxl_ctx = ctx;
out:
        return afu;
err3:
        ocxlflash_unconfig_afu(afu);
err2:
        ocxlflash_unconfig_fn(pdev, afu);
err1:
        idr_destroy(&afu->idr);
        kfree(afu);
        afu = NULL;
        goto out;
}

/**
 * ctx_event_pending() - check for any event pending on the context
 * @ctx:        Context to be checked.
 *
 * Return: true if there is an event pending, false if none pending
 */
static inline bool ctx_event_pending(struct ocxlflash_context *ctx)
{
        if (ctx->pending_irq || ctx->pending_fault)
                return true;

        return false;
}

/**
 * afu_poll() - poll the AFU for events on the context
 * @file:       File associated with the adapter context.
 * @poll:       Poll structure from the user.
 *
 * Return: poll mask
 */

static unsigned int afu_poll(struct file *file, struct poll_table_struct *poll)
{
        struct ocxlflash_context *ctx = file->private_data;
        struct device *dev = ctx->hw_afu->dev;
        ulong lock_flags;
        int mask = 0;

        poll_wait(file, &ctx->wq, poll);

        spin_lock_irqsave(&ctx->slock, lock_flags);
        if (ctx_event_pending(ctx))
                mask |= POLLIN | POLLRDNORM;
        else if (ctx->state == CLOSED)
                mask |= POLLERR;
        spin_unlock_irqrestore(&ctx->slock, lock_flags);

        dev_dbg(dev, "%s: Poll wait completed for pe %i mask %i\n",
                __func__, ctx->pe, mask);

        return mask;
}

/**
 * afu_read() - perform a read on the context for any event
 * @file:       File associated with the adapter context.
 * @buf:        Buffer to receive the data.
 * @count:      Size of buffer (maximum bytes that can be read).
 * @off:        Offset.
 *
 * Return: size of the data read on success, -errno on failure
 */
static ssize_t afu_read(struct file *file, char __user *buf, size_t count,
                        loff_t *off)
{
        struct ocxlflash_context *ctx = file->private_data;
        struct device *dev = ctx->hw_afu->dev;
        struct cxl_event event;
        ulong lock_flags;
        ssize_t esize;
        ssize_t rc;
        int bit;
        DEFINE_WAIT(event_wait);

        if (*off != 0) {
                dev_err(dev, "%s: Non-zero offset not supported, off=%lld\n",
                        __func__, *off);
                rc = -EINVAL;
                goto out;
        }

        spin_lock_irqsave(&ctx->slock, lock_flags);

        for (;;) {
                prepare_to_wait(&ctx->wq, &event_wait, TASK_INTERRUPTIBLE);

                if (ctx_event_pending(ctx) || (ctx->state == CLOSED))
                        break;

                if (file->f_flags & O_NONBLOCK) {
                        dev_err(dev, "%s: File cannot be blocked on I/O\n",
                                __func__);
                        rc = -EAGAIN;
                        goto err;
                }

                if (signal_pending(current)) {
                        dev_err(dev, "%s: Signal pending on the process\n",
                                __func__);
                        rc = -ERESTARTSYS;
                        goto err;
                }

                spin_unlock_irqrestore(&ctx->slock, lock_flags);
                schedule();
                spin_lock_irqsave(&ctx->slock, lock_flags);
        }

        finish_wait(&ctx->wq, &event_wait);

        memset(&event, 0, sizeof(event));
        event.header.process_element = ctx->pe;
        event.header.size = sizeof(struct cxl_event_header);
        if (ctx->pending_irq) {
                esize = sizeof(struct cxl_event_afu_interrupt);
                event.header.size += esize;
                event.header.type = CXL_EVENT_AFU_INTERRUPT;

                bit = find_first_bit(&ctx->irq_bitmap, ctx->num_irqs);
                clear_bit(bit, &ctx->irq_bitmap);
                event.irq.irq = bit + 1;
                if (bitmap_empty(&ctx->irq_bitmap, ctx->num_irqs))
                        ctx->pending_irq = false;
        } else if (ctx->pending_fault) {
                event.header.size += sizeof(struct cxl_event_data_storage);
                event.header.type = CXL_EVENT_DATA_STORAGE;
                event.fault.addr = ctx->fault_addr;
                event.fault.dsisr = ctx->fault_dsisr;
                ctx->pending_fault = false;
        }

        spin_unlock_irqrestore(&ctx->slock, lock_flags);

        if (copy_to_user(buf, &event, event.header.size)) {
                dev_err(dev, "%s: copy_to_user failed\n", __func__);
                rc = -EFAULT;
                goto out;
        }

        rc = event.header.size;
out:
        return rc;
err:
        finish_wait(&ctx->wq, &event_wait);
        spin_unlock_irqrestore(&ctx->slock, lock_flags);
        goto out;
}

/**
 * afu_release() - release and free the context
 * @inode:      File inode pointer.
 * @file:       File associated with the context.
 *
 * Return: 0 on success, -errno on failure
 */
static int afu_release(struct inode *inode, struct file *file)
{
        struct ocxlflash_context *ctx = file->private_data;
        int i;

        /* Unmap and free the interrupts associated with the context */
        for (i = ctx->num_irqs; i >= 0; i--)
                afu_unmap_irq(0, ctx, i, ctx);
        free_afu_irqs(ctx);

        return ocxlflash_release_context(ctx);
}

/**
 * ocxlflash_mmap_fault() - mmap fault handler
 * @vmf:        VM fault associated with current fault.
 *
 * Return: 0 on success, -errno on failure
 */
static vm_fault_t ocxlflash_mmap_fault(struct vm_fault *vmf)
{
        struct vm_area_struct *vma = vmf->vma;
        struct ocxlflash_context *ctx = vma->vm_file->private_data;
        struct device *dev = ctx->hw_afu->dev;
        u64 mmio_area, offset;

        offset = vmf->pgoff << PAGE_SHIFT;
        if (offset >= ctx->psn_size)
                return VM_FAULT_SIGBUS;

        mutex_lock(&ctx->state_mutex);
        if (ctx->state != STARTED) {
                dev_err(dev, "%s: Context not started, state=%d\n",
                        __func__, ctx->state);
                mutex_unlock(&ctx->state_mutex);
                return VM_FAULT_SIGBUS;
        }
        mutex_unlock(&ctx->state_mutex);

        mmio_area = ctx->psn_phys;
        mmio_area += offset;

        return vmf_insert_pfn(vma, vmf->address, mmio_area >> PAGE_SHIFT);
}

static const struct vm_operations_struct ocxlflash_vmops = {
        .fault = ocxlflash_mmap_fault,
};

/**
 * afu_mmap() - map the fault handler operations
 * @file:       File associated with the context.
 * @vma:        VM area associated with mapping.
 *
 * Return: 0 on success, -errno on failure
 */
static int afu_mmap(struct file *file, struct vm_area_struct *vma)
{
        struct ocxlflash_context *ctx = file->private_data;

        if ((vma_pages(vma) + vma->vm_pgoff) >
            (ctx->psn_size >> PAGE_SHIFT))
                return -EINVAL;

        vma->vm_flags |= VM_IO | VM_PFNMAP;
        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
        vma->vm_ops = &ocxlflash_vmops;
        return 0;
}

static const struct file_operations ocxl_afu_fops = {
        .owner          = THIS_MODULE,
        .poll           = afu_poll,
        .read           = afu_read,
        .release        = afu_release,
        .mmap           = afu_mmap,
};

#define PATCH_FOPS(NAME)                                                \
        do { if (!fops->NAME) fops->NAME = ocxl_afu_fops.NAME; } while (0)

/**
 * ocxlflash_get_fd() - get file descriptor for an adapter context
 * @ctx_cookie: Adapter context.
 * @fops:       File operations to be associated.
 * @fd:         File descriptor to be returned back.
 *
 * Return: pointer to the file on success, ERR_PTR on failure
 */
static struct file *ocxlflash_get_fd(void *ctx_cookie,
                                     struct file_operations *fops, int *fd)
{
        struct ocxlflash_context *ctx = ctx_cookie;
        struct device *dev = ctx->hw_afu->dev;
        struct file *file;
        int flags, fdtmp;
        int rc = 0;
        char *name = NULL;

        /* Only allow one fd per context */
        if (ctx->mapping) {
                dev_err(dev, "%s: Context is already mapped to an fd\n",
                        __func__);
                rc = -EEXIST;
                goto err1;
        }

        flags = O_RDWR | O_CLOEXEC;

        /* This code is similar to anon_inode_getfd() */
        rc = get_unused_fd_flags(flags);
        if (unlikely(rc < 0)) {
                dev_err(dev, "%s: get_unused_fd_flags failed rc=%d\n",
                        __func__, rc);
                goto err1;
        }
        fdtmp = rc;

        /* Patch the file ops that are not defined */
        if (fops) {
                PATCH_FOPS(poll);
                PATCH_FOPS(read);
                PATCH_FOPS(release);
                PATCH_FOPS(mmap);
        } else /* Use default ops */
                fops = (struct file_operations *)&ocxl_afu_fops;

        name = kasprintf(GFP_KERNEL, "ocxlflash:%d", ctx->pe);
        file = ocxlflash_getfile(dev, name, fops, ctx, flags);
        kfree(name);
        if (IS_ERR(file)) {
                rc = PTR_ERR(file);
                dev_err(dev, "%s: ocxlflash_getfile failed rc=%d\n",
                        __func__, rc);
                goto err2;
        }

        ctx->mapping = file->f_mapping;
        *fd = fdtmp;
out:
        return file;
err2:
        put_unused_fd(fdtmp);
err1:
        file = ERR_PTR(rc);
        goto out;
}

/**
 * ocxlflash_fops_get_context() - get the context associated with the file
 * @file:       File associated with the adapter context.
 *
 * Return: pointer to the context
 */
static void *ocxlflash_fops_get_context(struct file *file)
{
        return file->private_data;
}

/**
 * ocxlflash_afu_irq() - interrupt handler for user contexts
 * @irq:        Interrupt number.
 * @data:       Private data provided at interrupt registration, the context.
 *
 * Return: Always return IRQ_HANDLED.
 */
static irqreturn_t ocxlflash_afu_irq(int irq, void *data)
{
        struct ocxlflash_context *ctx = data;
        struct device *dev = ctx->hw_afu->dev;
        int i;

        dev_dbg(dev, "%s: Interrupt raised for pe %i virq %i\n",
                __func__, ctx->pe, irq);

        for (i = 0; i < ctx->num_irqs; i++) {
                if (ctx->irqs[i].virq == irq)
                        break;
        }
        if (unlikely(i >= ctx->num_irqs)) {
                dev_err(dev, "%s: Received AFU IRQ out of range\n", __func__);
                goto out;
        }

        spin_lock(&ctx->slock);
        set_bit(i - 1, &ctx->irq_bitmap);
        ctx->pending_irq = true;
        spin_unlock(&ctx->slock);

        wake_up_all(&ctx->wq);
out:
        return IRQ_HANDLED;
}

/**
 * ocxlflash_start_work() - start a user context
 * @ctx_cookie: Context to be started.
 * @num_irqs:   Number of interrupts requested.
 *
 * Return: 0 on success, -errno on failure
 */
static int ocxlflash_start_work(void *ctx_cookie, u64 num_irqs)
{
        struct ocxlflash_context *ctx = ctx_cookie;
        struct ocxl_hw_afu *afu = ctx->hw_afu;
        struct device *dev = afu->dev;
        char *name;
        int rc = 0;
        int i;

        rc = alloc_afu_irqs(ctx, num_irqs);
        if (unlikely(rc < 0)) {
                dev_err(dev, "%s: alloc_afu_irqs failed rc=%d\n", __func__, rc);
                goto out;
        }

        for (i = 0; i < num_irqs; i++) {
                name = kasprintf(GFP_KERNEL, "ocxlflash-%s-pe%i-%i",
                                 dev_name(dev), ctx->pe, i);
                rc = afu_map_irq(0, ctx, i, ocxlflash_afu_irq, ctx, name);
                kfree(name);
                if (unlikely(rc < 0)) {
                        dev_err(dev, "%s: afu_map_irq failed rc=%d\n",
                                __func__, rc);
                        goto err;
                }
        }

        rc = start_context(ctx);
        if (unlikely(rc)) {
                dev_err(dev, "%s: start_context failed rc=%d\n", __func__, rc);
                goto err;
        }
out:
        return rc;
err:
        for (i = i-1; i >= 0; i--)
                afu_unmap_irq(0, ctx, i, ctx);
        free_afu_irqs(ctx);
        goto out;
};

/**
 * ocxlflash_fd_mmap() - mmap handler for adapter file descriptor
 * @file:       File installed with adapter file descriptor.
 * @vma:        VM area associated with mapping.
 *
 * Return: 0 on success, -errno on failure
 */
static int ocxlflash_fd_mmap(struct file *file, struct vm_area_struct *vma)
{
        return afu_mmap(file, vma);
}

/**
 * ocxlflash_fd_release() - release the context associated with the file
 * @inode:      File inode pointer.
 * @file:       File associated with the adapter context.
 *
 * Return: 0 on success, -errno on failure
 */
static int ocxlflash_fd_release(struct inode *inode, struct file *file)
{
        return afu_release(inode, file);
}

/* Backend ops to ocxlflash services */
const struct cxlflash_backend_ops cxlflash_ocxl_ops = {
        .module                 = THIS_MODULE,
        .psa_map                = ocxlflash_psa_map,
        .psa_unmap              = ocxlflash_psa_unmap,
        .process_element        = ocxlflash_process_element,
        .map_afu_irq            = ocxlflash_map_afu_irq,
        .unmap_afu_irq          = ocxlflash_unmap_afu_irq,
        .get_irq_objhndl        = ocxlflash_get_irq_objhndl,
        .start_context          = ocxlflash_start_context,
        .stop_context           = ocxlflash_stop_context,
        .afu_reset              = ocxlflash_afu_reset,
        .set_master             = ocxlflash_set_master,
        .get_context            = ocxlflash_get_context,
        .dev_context_init       = ocxlflash_dev_context_init,
        .release_context        = ocxlflash_release_context,
        .perst_reloads_same_image = ocxlflash_perst_reloads_same_image,
        .read_adapter_vpd       = ocxlflash_read_adapter_vpd,
        .allocate_afu_irqs      = ocxlflash_allocate_afu_irqs,
        .free_afu_irqs          = ocxlflash_free_afu_irqs,
        .create_afu             = ocxlflash_create_afu,
        .destroy_afu            = ocxlflash_destroy_afu,
        .get_fd                 = ocxlflash_get_fd,
        .fops_get_context       = ocxlflash_fops_get_context,
        .start_work             = ocxlflash_start_work,
        .fd_mmap                = ocxlflash_fd_mmap,
        .fd_release             = ocxlflash_fd_release,
};