// SPDX-License-Identifier: GPL-2.0+
// Copyright 2019 IBM Corp.
#include <linux/idr.h>
#include "ocxl_internal.h"

static struct ocxl_fn *ocxl_fn_get(struct ocxl_fn *fn)
{
        return (get_device(&fn->dev) == NULL) ? NULL : fn;
}

static void ocxl_fn_put(struct ocxl_fn *fn)
{
        put_device(&fn->dev);
}

static struct ocxl_afu *alloc_afu(struct ocxl_fn *fn)
{
        struct ocxl_afu *afu;

        afu = kzalloc(sizeof(struct ocxl_afu), GFP_KERNEL);
        if (!afu)
                return NULL;

        kref_init(&afu->kref);
        mutex_init(&afu->contexts_lock);
        mutex_init(&afu->afu_control_lock);
        idr_init(&afu->contexts_idr);
        afu->fn = fn;
        ocxl_fn_get(fn);
        return afu;
}

static void free_afu(struct kref *kref)
{
        struct ocxl_afu *afu = container_of(kref, struct ocxl_afu, kref);

        idr_destroy(&afu->contexts_idr);
        ocxl_fn_put(afu->fn);
        kfree(afu);
}

void ocxl_afu_get(struct ocxl_afu *afu)
{
        kref_get(&afu->kref);
}
EXPORT_SYMBOL_GPL(ocxl_afu_get);

void ocxl_afu_put(struct ocxl_afu *afu)
{
        kref_put(&afu->kref, free_afu);
}
EXPORT_SYMBOL_GPL(ocxl_afu_put);

static int assign_afu_actag(struct ocxl_afu *afu)
{
        struct ocxl_fn *fn = afu->fn;
        int actag_count, actag_offset;
        struct pci_dev *pci_dev = to_pci_dev(fn->dev.parent);

        /*
         * if there were not enough actags for the function, each afu
         * reduces its count as well
         */
        actag_count = afu->config.actag_supported *
                fn->actag_enabled / fn->actag_supported;
        actag_offset = ocxl_actag_afu_alloc(fn, actag_count);
        if (actag_offset < 0) {
                dev_err(&pci_dev->dev, "Can't allocate %d actags for AFU: %d\n",
                        actag_count, actag_offset);
                return actag_offset;
        }
        afu->actag_base = fn->actag_base + actag_offset;
        afu->actag_enabled = actag_count;

        ocxl_config_set_afu_actag(pci_dev, afu->config.dvsec_afu_control_pos,
                                afu->actag_base, afu->actag_enabled);
        dev_dbg(&pci_dev->dev, "actag base=%d enabled=%d\n",
                afu->actag_base, afu->actag_enabled);
        return 0;
}

static void reclaim_afu_actag(struct ocxl_afu *afu)
{
        struct ocxl_fn *fn = afu->fn;
        int start_offset, size;

        start_offset = afu->actag_base - fn->actag_base;
        size = afu->actag_enabled;
        ocxl_actag_afu_free(afu->fn, start_offset, size);
}

static int assign_afu_pasid(struct ocxl_afu *afu)
{
        struct ocxl_fn *fn = afu->fn;
        int pasid_count, pasid_offset;
        struct pci_dev *pci_dev = to_pci_dev(fn->dev.parent);

        /*
         * We only support the case where the function configuration
         * requested enough PASIDs to cover all AFUs.
         */
        pasid_count = 1 << afu->config.pasid_supported_log;
        pasid_offset = ocxl_pasid_afu_alloc(fn, pasid_count);
        if (pasid_offset < 0) {
                dev_err(&pci_dev->dev, "Can't allocate %d PASIDs for AFU: %d\n",
                        pasid_count, pasid_offset);
                return pasid_offset;
        }
        afu->pasid_base = fn->pasid_base + pasid_offset;
        afu->pasid_count = 0;
        afu->pasid_max = pasid_count;

        ocxl_config_set_afu_pasid(pci_dev, afu->config.dvsec_afu_control_pos,
                                afu->pasid_base,
                                afu->config.pasid_supported_log);
        dev_dbg(&pci_dev->dev, "PASID base=%d, enabled=%d\n",
                afu->pasid_base, pasid_count);
        return 0;
}

static void reclaim_afu_pasid(struct ocxl_afu *afu)
{
        struct ocxl_fn *fn = afu->fn;
        int start_offset, size;

        start_offset = afu->pasid_base - fn->pasid_base;
        size = 1 << afu->config.pasid_supported_log;
        ocxl_pasid_afu_free(afu->fn, start_offset, size);
}

static int reserve_fn_bar(struct ocxl_fn *fn, int bar)
{
        struct pci_dev *dev = to_pci_dev(fn->dev.parent);
        int rc, idx;

        if (bar != 0 && bar != 2 && bar != 4)
                return -EINVAL;

        idx = bar >> 1;
        if (fn->bar_used[idx]++ == 0) {
                rc = pci_request_region(dev, bar, "ocxl");
                if (rc)
                        return rc;
        }
        return 0;
}

static void release_fn_bar(struct ocxl_fn *fn, int bar)
{
        struct pci_dev *dev = to_pci_dev(fn->dev.parent);
        int idx;

        if (bar != 0 && bar != 2 && bar != 4)
                return;

        idx = bar >> 1;
        if (--fn->bar_used[idx] == 0)
                pci_release_region(dev, bar);
        WARN_ON(fn->bar_used[idx] < 0);
}

static int map_mmio_areas(struct ocxl_afu *afu)
{
        int rc;
        struct pci_dev *pci_dev = to_pci_dev(afu->fn->dev.parent);

        rc = reserve_fn_bar(afu->fn, afu->config.global_mmio_bar);
        if (rc)
                return rc;

        rc = reserve_fn_bar(afu->fn, afu->config.pp_mmio_bar);
        if (rc) {
                release_fn_bar(afu->fn, afu->config.global_mmio_bar);
                return rc;
        }

        afu->global_mmio_start =
                pci_resource_start(pci_dev, afu->config.global_mmio_bar) +
                afu->config.global_mmio_offset;
        afu->pp_mmio_start =
                pci_resource_start(pci_dev, afu->config.pp_mmio_bar) +
                afu->config.pp_mmio_offset;

        afu->global_mmio_ptr = ioremap(afu->global_mmio_start,
                                afu->config.global_mmio_size);
        if (!afu->global_mmio_ptr) {
                release_fn_bar(afu->fn, afu->config.pp_mmio_bar);
                release_fn_bar(afu->fn, afu->config.global_mmio_bar);
                dev_err(&pci_dev->dev, "Error mapping global mmio area\n");
                return -ENOMEM;
        }

        /*
         * Leave an empty page between the per-process mmio area and
         * the AFU interrupt mappings
         */
        afu->irq_base_offset = afu->config.pp_mmio_stride + PAGE_SIZE;
        return 0;
}

static void unmap_mmio_areas(struct ocxl_afu *afu)
{
        if (afu->global_mmio_ptr) {
                iounmap(afu->global_mmio_ptr);
                afu->global_mmio_ptr = NULL;
        }
        afu->global_mmio_start = 0;
        afu->pp_mmio_start = 0;
        release_fn_bar(afu->fn, afu->config.pp_mmio_bar);
        release_fn_bar(afu->fn, afu->config.global_mmio_bar);
}

static int configure_afu(struct ocxl_afu *afu, u8 afu_idx, struct pci_dev *dev)
{
        int rc;

        rc = ocxl_config_read_afu(dev, &afu->fn->config, &afu->config, afu_idx);
        if (rc)
                return rc;

        rc = assign_afu_actag(afu);
        if (rc)
                return rc;

        rc = assign_afu_pasid(afu);
        if (rc)
                goto err_free_actag;

        rc = map_mmio_areas(afu);
        if (rc)
                goto err_free_pasid;

        return 0;

err_free_pasid:
        reclaim_afu_pasid(afu);
err_free_actag:
        reclaim_afu_actag(afu);
        return rc;
}

static void deconfigure_afu(struct ocxl_afu *afu)
{
        unmap_mmio_areas(afu);
        reclaim_afu_pasid(afu);
        reclaim_afu_actag(afu);
}

static int activate_afu(struct pci_dev *dev, struct ocxl_afu *afu)
{
        ocxl_config_set_afu_state(dev, afu->config.dvsec_afu_control_pos, 1);

        return 0;
}

static void deactivate_afu(struct ocxl_afu *afu)
{
        struct pci_dev *dev = to_pci_dev(afu->fn->dev.parent);

        ocxl_config_set_afu_state(dev, afu->config.dvsec_afu_control_pos, 0);
}

static int init_afu(struct pci_dev *dev, struct ocxl_fn *fn, u8 afu_idx)
{
        int rc;
        struct ocxl_afu *afu;

        afu = alloc_afu(fn);
        if (!afu)
                return -ENOMEM;

        rc = configure_afu(afu, afu_idx, dev);
        if (rc) {
                ocxl_afu_put(afu);
                return rc;
        }

        rc = activate_afu(dev, afu);
        if (rc) {
                deconfigure_afu(afu);
                ocxl_afu_put(afu);
                return rc;
        }

        list_add_tail(&afu->list, &fn->afu_list);

        return 0;
}

static void remove_afu(struct ocxl_afu *afu)
{
        list_del(&afu->list);
        ocxl_context_detach_all(afu);
        deactivate_afu(afu);
        deconfigure_afu(afu);
        ocxl_afu_put(afu); // matches the implicit get in alloc_afu
}

static struct ocxl_fn *alloc_function(void)
{
        struct ocxl_fn *fn;

        fn = kzalloc(sizeof(struct ocxl_fn), GFP_KERNEL);
        if (!fn)
                return NULL;

        INIT_LIST_HEAD(&fn->afu_list);
        INIT_LIST_HEAD(&fn->pasid_list);
        INIT_LIST_HEAD(&fn->actag_list);

        return fn;
}

static void free_function(struct ocxl_fn *fn)
{
        WARN_ON(!list_empty(&fn->afu_list));
        WARN_ON(!list_empty(&fn->pasid_list));
        kfree(fn);
}

static void free_function_dev(struct device *dev)
{
        struct ocxl_fn *fn = container_of(dev, struct ocxl_fn, dev);

        free_function(fn);
}

static int set_function_device(struct ocxl_fn *fn, struct pci_dev *dev)
{
        fn->dev.parent = &dev->dev;
        fn->dev.release = free_function_dev;
        return dev_set_name(&fn->dev, "ocxlfn.%s", dev_name(&dev->dev));
}

static int assign_function_actag(struct ocxl_fn *fn)
{
        struct pci_dev *dev = to_pci_dev(fn->dev.parent);
        u16 base, enabled, supported;
        int rc;

        rc = ocxl_config_get_actag_info(dev, &base, &enabled, &supported);
        if (rc)
                return rc;

        fn->actag_base = base;
        fn->actag_enabled = enabled;
        fn->actag_supported = supported;

        ocxl_config_set_actag(dev, fn->config.dvsec_function_pos,
                        fn->actag_base, fn->actag_enabled);
        dev_dbg(&fn->dev, "actag range starting at %d, enabled %d\n",
                fn->actag_base, fn->actag_enabled);
        return 0;
}

static int set_function_pasid(struct ocxl_fn *fn)
{
        struct pci_dev *dev = to_pci_dev(fn->dev.parent);
        int rc, desired_count, max_count;

        /* A function may not require any PASID */
        if (fn->config.max_pasid_log < 0)
                return 0;

        rc = ocxl_config_get_pasid_info(dev, &max_count);
        if (rc)
                return rc;

        desired_count = 1 << fn->config.max_pasid_log;

        if (desired_count > max_count) {
                dev_err(&fn->dev,
                        "Function requires more PASIDs than is available (%d vs. %d)\n",
                        desired_count, max_count);
                return -ENOSPC;
        }

        fn->pasid_base = 0;
        return 0;
}

static int configure_function(struct ocxl_fn *fn, struct pci_dev *dev)
{
        int rc;

        rc = pci_enable_device(dev);
        if (rc) {
                dev_err(&dev->dev, "pci_enable_device failed: %d\n", rc);
                return rc;
        }

        /*
         * Once it has been confirmed to work on our hardware, we
         * should reset the function, to force the adapter to restart
         * from scratch.
         * A function reset would also reset all its AFUs.
         *
         * Some hints for implementation:
         *
         * - there's not status bit to know when the reset is done. We
         *   should try reading the config space to know when it's
         *   done.
         * - probably something like:
         *      Reset
         *      wait 100ms
         *      issue config read
         *      allow device up to 1 sec to return success on config
         *      read before declaring it broken
         *
         * Some shared logic on the card (CFG, TLX) won't be reset, so
         * there's no guarantee that it will be enough.
         */
        rc = ocxl_config_read_function(dev, &fn->config);
        if (rc)
                return rc;

        rc = set_function_device(fn, dev);
        if (rc)
                return rc;

        rc = assign_function_actag(fn);
        if (rc)
                return rc;

        rc = set_function_pasid(fn);
        if (rc)
                return rc;

        rc = ocxl_link_setup(dev, 0, &fn->link);
        if (rc)
                return rc;

        rc = ocxl_config_set_TL(dev, fn->config.dvsec_tl_pos);
        if (rc) {
                ocxl_link_release(dev, fn->link);
                return rc;
        }
        return 0;
}

static void deconfigure_function(struct ocxl_fn *fn)
{
        struct pci_dev *dev = to_pci_dev(fn->dev.parent);

        ocxl_link_release(dev, fn->link);
        pci_disable_device(dev);
}

static struct ocxl_fn *init_function(struct pci_dev *dev)
{
        struct ocxl_fn *fn;
        int rc;

        fn = alloc_function();
        if (!fn)
                return ERR_PTR(-ENOMEM);

        rc = configure_function(fn, dev);
        if (rc) {
                free_function(fn);
                return ERR_PTR(rc);
        }

        rc = device_register(&fn->dev);
        if (rc) {
                deconfigure_function(fn);
                put_device(&fn->dev);
                return ERR_PTR(rc);
        }
        return fn;
}

// Device detection & initialisation

struct ocxl_fn *ocxl_function_open(struct pci_dev *dev)
{
        int rc, afu_count = 0;
        u8 afu;
        struct ocxl_fn *fn;

        if (!radix_enabled()) {
                dev_err(&dev->dev, "Unsupported memory model (hash)\n");
                return ERR_PTR(-ENODEV);
        }

        fn = init_function(dev);
        if (IS_ERR(fn)) {
                dev_err(&dev->dev, "function init failed: %li\n",
                        PTR_ERR(fn));
                return fn;
        }

        for (afu = 0; afu <= fn->config.max_afu_index; afu++) {
                rc = ocxl_config_check_afu_index(dev, &fn->config, afu);
                if (rc > 0) {
                        rc = init_afu(dev, fn, afu);
                        if (rc) {
                                dev_err(&dev->dev,
                                        "Can't initialize AFU index %d\n", afu);
                                continue;
                        }
                        afu_count++;
                }
        }
        dev_info(&dev->dev, "%d AFU(s) configured\n", afu_count);
        return fn;
}
EXPORT_SYMBOL_GPL(ocxl_function_open);

struct list_head *ocxl_function_afu_list(struct ocxl_fn *fn)
{
        return &fn->afu_list;
}
EXPORT_SYMBOL_GPL(ocxl_function_afu_list);

struct ocxl_afu *ocxl_function_fetch_afu(struct ocxl_fn *fn, u8 afu_idx)
{
        struct ocxl_afu *afu;

        list_for_each_entry(afu, &fn->afu_list, list) {
                if (afu->config.idx == afu_idx)
                        return afu;
        }

        return NULL;
}
EXPORT_SYMBOL_GPL(ocxl_function_fetch_afu);

const struct ocxl_fn_config *ocxl_function_config(struct ocxl_fn *fn)
{
        return &fn->config;
}
EXPORT_SYMBOL_GPL(ocxl_function_config);

void ocxl_function_close(struct ocxl_fn *fn)
{
        struct ocxl_afu *afu, *tmp;

        list_for_each_entry_safe(afu, tmp, &fn->afu_list, list) {
                remove_afu(afu);
        }

        deconfigure_function(fn);
        device_unregister(&fn->dev);
}
EXPORT_SYMBOL_GPL(ocxl_function_close);

// AFU Metadata

struct ocxl_afu_config *ocxl_afu_config(struct ocxl_afu *afu)
{
        return &afu->config;
}
EXPORT_SYMBOL_GPL(ocxl_afu_config);

void ocxl_afu_set_private(struct ocxl_afu *afu, void *private)
{
        afu->private = private;
}
EXPORT_SYMBOL_GPL(ocxl_afu_set_private);

void *ocxl_afu_get_private(struct ocxl_afu *afu)
{
        if (afu)
                return afu->private;

        return NULL;
}
EXPORT_SYMBOL_GPL(ocxl_afu_get_private);