// SPDX-License-Identifier: GPL-2.0-only
// SPDX-FileCopyrightText: Copyright Red Hat

#include <linux/cleanup.h>
#include <linux/mutex.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/xarray.h>
#include "ice_adapter.h"
#include "ice.h"

static DEFINE_XARRAY(ice_adapters);
static DEFINE_MUTEX(ice_adapters_mutex);

#define ICE_ADAPTER_FIXED_INDEX BIT_ULL(63)

#define ICE_ADAPTER_INDEX_E825C \
        (ICE_DEV_ID_E825C_BACKPLANE | ICE_ADAPTER_FIXED_INDEX)

static u64 ice_adapter_index(struct pci_dev *pdev)
{
        switch (pdev->device) {
        case ICE_DEV_ID_E825C_BACKPLANE:
        case ICE_DEV_ID_E825C_QSFP:
        case ICE_DEV_ID_E825C_SFP:
        case ICE_DEV_ID_E825C_SGMII:
                /* E825C devices have multiple NACs which are connected to the
                 * same clock source, and which must share the same
                 * ice_adapter structure. We can't use the serial number since
                 * each NAC has its own NVM generated with its own unique
                 * Device Serial Number. Instead, rely on the embedded nature
                 * of the E825C devices, and use a fixed index. This relies on
                 * the fact that all E825C physical functions in a given
                 * system are part of the same overall device.
                 */
                return ICE_ADAPTER_INDEX_E825C;
        default:
                return pci_get_dsn(pdev) & ~ICE_ADAPTER_FIXED_INDEX;
        }
}

static unsigned long ice_adapter_xa_index(struct pci_dev *pdev)
{
        u64 index = ice_adapter_index(pdev);

#if BITS_PER_LONG == 64
        return index;
#else
        return (u32)index ^ (u32)(index >> 32);
#endif
}

static struct ice_adapter *ice_adapter_new(struct pci_dev *pdev)
{
        struct ice_adapter *adapter;

        adapter = kzalloc_obj(*adapter);
        if (!adapter)
                return NULL;

        adapter->index = ice_adapter_index(pdev);
        spin_lock_init(&adapter->ptp_gltsyn_time_lock);
        spin_lock_init(&adapter->txq_ctx_lock);
        refcount_set(&adapter->refcount, 1);

        mutex_init(&adapter->ports.lock);
        INIT_LIST_HEAD(&adapter->ports.ports);

        return adapter;
}

static void ice_adapter_free(struct ice_adapter *adapter)
{
        WARN_ON(!list_empty(&adapter->ports.ports));
        mutex_destroy(&adapter->ports.lock);

        kfree(adapter);
}

/**
 * ice_adapter_get - Get a shared ice_adapter structure.
 * @pdev: Pointer to the pci_dev whose driver is getting the ice_adapter.
 *
 * Gets a pointer to a shared ice_adapter structure. Physical functions (PFs)
 * of the same multi-function PCI device share one ice_adapter structure.
 * The ice_adapter is reference-counted. The PF driver must use ice_adapter_put
 * to release its reference.
 *
 * Context: Process, may sleep.
 * Return:  Pointer to ice_adapter on success.
 *          ERR_PTR() on error. -ENOMEM is the only possible error.
 */
struct ice_adapter *ice_adapter_get(struct pci_dev *pdev)
{
        struct ice_adapter *adapter;
        unsigned long index;
        int err;

        index = ice_adapter_xa_index(pdev);
        scoped_guard(mutex, &ice_adapters_mutex) {
                adapter = xa_load(&ice_adapters, index);
                if (adapter) {
                        refcount_inc(&adapter->refcount);
                        WARN_ON_ONCE(adapter->index != ice_adapter_index(pdev));
                        return adapter;
                }
                err = xa_reserve(&ice_adapters, index, GFP_KERNEL);
                if (err)
                        return ERR_PTR(err);

                adapter = ice_adapter_new(pdev);
                if (!adapter) {
                        xa_release(&ice_adapters, index);
                        return ERR_PTR(-ENOMEM);
                }
                xa_store(&ice_adapters, index, adapter, GFP_KERNEL);
        }
        return adapter;
}

/**
 * ice_adapter_put - Release a reference to the shared ice_adapter structure.
 * @pdev: Pointer to the pci_dev whose driver is releasing the ice_adapter.
 *
 * Releases the reference to ice_adapter previously obtained with
 * ice_adapter_get.
 *
 * Context: Process, may sleep.
 */
void ice_adapter_put(struct pci_dev *pdev)
{
        struct ice_adapter *adapter;
        unsigned long index;

        index = ice_adapter_xa_index(pdev);
        scoped_guard(mutex, &ice_adapters_mutex) {
                adapter = xa_load(&ice_adapters, index);
                if (WARN_ON(!adapter))
                        return;
                if (!refcount_dec_and_test(&adapter->refcount))
                        return;

                WARN_ON(xa_erase(&ice_adapters, index) != adapter);
        }
        ice_adapter_free(adapter);
}