// SPDX-License-Identifier: GPL-2.0-only
/*
 * AMD Secure Processor driver
 *
 * Copyright (C) 2017-2018 Advanced Micro Devices, Inc.
 *
 * Author: Tom Lendacky <thomas.lendacky@amd.com>
 * Author: Gary R Hook <gary.hook@amd.com>
 * Author: Brijesh Singh <brijesh.singh@amd.com>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/spinlock_types.h>
#include <linux/types.h>
#include <linux/ccp.h>

#include "sev-dev.h"
#include "ccp-dev.h"
#include "sp-dev.h"

MODULE_AUTHOR("Tom Lendacky <thomas.lendacky@amd.com>");
MODULE_AUTHOR("Gary R Hook <gary.hook@amd.com>");
MODULE_LICENSE("GPL");
MODULE_VERSION("1.1.0");
MODULE_DESCRIPTION("AMD Secure Processor driver");

/* List of SPs, SP count, read-write access lock, and access functions
 *
 * Lock structure: get sp_unit_lock for reading whenever we need to
 * examine the SP list.
 */
static DEFINE_RWLOCK(sp_unit_lock);
static LIST_HEAD(sp_units);

/* Ever-increasing value to produce unique unit numbers */
static atomic_t sp_ordinal;

static void sp_add_device(struct sp_device *sp)
{
        unsigned long flags;

        write_lock_irqsave(&sp_unit_lock, flags);

        list_add_tail(&sp->entry, &sp_units);

        write_unlock_irqrestore(&sp_unit_lock, flags);
}

static void sp_del_device(struct sp_device *sp)
{
        unsigned long flags;

        write_lock_irqsave(&sp_unit_lock, flags);

        list_del(&sp->entry);

        write_unlock_irqrestore(&sp_unit_lock, flags);
}

static irqreturn_t sp_irq_handler(int irq, void *data)
{
        struct sp_device *sp = data;

        if (sp->ccp_irq_handler)
                sp->ccp_irq_handler(irq, sp->ccp_irq_data);

        if (sp->psp_irq_handler)
                sp->psp_irq_handler(irq, sp->psp_irq_data);

        return IRQ_HANDLED;
}

int sp_request_ccp_irq(struct sp_device *sp, irq_handler_t handler,
                       const char *name, void *data)
{
        int ret;

        if ((sp->psp_irq == sp->ccp_irq) && sp->dev_vdata->psp_vdata) {
                /* Need a common routine to manage all interrupts */
                sp->ccp_irq_data = data;
                sp->ccp_irq_handler = handler;

                if (!sp->irq_registered) {
                        ret = request_irq(sp->ccp_irq, sp_irq_handler, 0,
                                          sp->name, sp);
                        if (ret)
                                return ret;

                        sp->irq_registered = true;
                }
        } else {
                /* Each sub-device can manage it's own interrupt */
                ret = request_irq(sp->ccp_irq, handler, 0, name, data);
                if (ret)
                        return ret;
        }

        return 0;
}

int sp_request_psp_irq(struct sp_device *sp, irq_handler_t handler,
                       const char *name, void *data)
{
        int ret;

        if ((sp->psp_irq == sp->ccp_irq) && sp->dev_vdata->ccp_vdata) {
                /* Need a common routine to manage all interrupts */
                sp->psp_irq_data = data;
                sp->psp_irq_handler = handler;

                if (!sp->irq_registered) {
                        ret = request_irq(sp->psp_irq, sp_irq_handler, 0,
                                          sp->name, sp);
                        if (ret)
                                return ret;

                        sp->irq_registered = true;
                }
        } else {
                /* Each sub-device can manage it's own interrupt */
                ret = request_irq(sp->psp_irq, handler, 0, name, data);
                if (ret)
                        return ret;
        }

        return 0;
}

void sp_free_ccp_irq(struct sp_device *sp, void *data)
{
        if ((sp->psp_irq == sp->ccp_irq) && sp->dev_vdata->psp_vdata) {
                /* Using common routine to manage all interrupts */
                if (!sp->psp_irq_handler) {
                        /* Nothing else using it, so free it */
                        free_irq(sp->ccp_irq, sp);

                        sp->irq_registered = false;
                }

                sp->ccp_irq_handler = NULL;
                sp->ccp_irq_data = NULL;
        } else {
                /* Each sub-device can manage it's own interrupt */
                free_irq(sp->ccp_irq, data);
        }
}

void sp_free_psp_irq(struct sp_device *sp, void *data)
{
        if ((sp->psp_irq == sp->ccp_irq) && sp->dev_vdata->ccp_vdata) {
                /* Using common routine to manage all interrupts */
                if (!sp->ccp_irq_handler) {
                        /* Nothing else using it, so free it */
                        free_irq(sp->psp_irq, sp);

                        sp->irq_registered = false;
                }

                sp->psp_irq_handler = NULL;
                sp->psp_irq_data = NULL;
        } else {
                /* Each sub-device can manage it's own interrupt */
                free_irq(sp->psp_irq, data);
        }
}

/**
 * sp_alloc_struct - allocate and initialize the sp_device struct
 *
 * @dev: device struct of the SP
 */
struct sp_device *sp_alloc_struct(struct device *dev)
{
        struct sp_device *sp;

        sp = devm_kzalloc(dev, sizeof(*sp), GFP_KERNEL);
        if (!sp)
                return NULL;

        sp->dev = dev;
        sp->ord = atomic_inc_return(&sp_ordinal);
        snprintf(sp->name, SP_MAX_NAME_LEN, "sp-%u", sp->ord);

        return sp;
}

int sp_init(struct sp_device *sp)
{
        sp_add_device(sp);

        if (sp->dev_vdata->ccp_vdata)
                ccp_dev_init(sp);

        if (sp->dev_vdata->psp_vdata)
                psp_dev_init(sp);
        return 0;
}

void sp_destroy(struct sp_device *sp)
{
        if (sp->dev_vdata->ccp_vdata)
                ccp_dev_destroy(sp);

        if (sp->dev_vdata->psp_vdata)
                psp_dev_destroy(sp);

        sp_del_device(sp);
}

int sp_suspend(struct sp_device *sp)
{
        if (sp->dev_vdata->ccp_vdata) {
                ccp_dev_suspend(sp);
        }

        return 0;
}

int sp_resume(struct sp_device *sp)
{
        if (sp->dev_vdata->ccp_vdata) {
                ccp_dev_resume(sp);
        }

        return 0;
}

int sp_restore(struct sp_device *sp)
{
        if (sp->psp_data) {
                int ret = psp_restore(sp);

                if (ret)
                        return ret;
        }

        return sp_resume(sp);
}

struct sp_device *sp_get_psp_master_device(void)
{
        struct sp_device *i, *ret = NULL;
        unsigned long flags;

        write_lock_irqsave(&sp_unit_lock, flags);
        if (list_empty(&sp_units))
                goto unlock;

        list_for_each_entry(i, &sp_units, entry) {
                if (i->psp_data && i->get_psp_master_device) {
                        ret = i->get_psp_master_device();
                        break;
                }
        }

unlock:
        write_unlock_irqrestore(&sp_unit_lock, flags);
        return ret;
}

static int __init sp_mod_init(void)
{
#ifdef CONFIG_X86
        static bool initialized;
        int ret;

        if (initialized)
                return 0;

        ret = sp_pci_init();
        if (ret)
                return ret;

#ifdef CONFIG_CRYPTO_DEV_SP_PSP
        psp_pci_init();
#endif

        initialized = true;

        return 0;
#endif

#ifdef CONFIG_ARM64
        int ret;

        ret = sp_platform_init();
        if (ret)
                return ret;

        return 0;
#endif

        return -ENODEV;
}

#if IS_BUILTIN(CONFIG_KVM_AMD) && IS_ENABLED(CONFIG_KVM_AMD_SEV)
int __init sev_module_init(void)
{
        return sp_mod_init();
}
#endif

static void __exit sp_mod_exit(void)
{
#ifdef CONFIG_X86

#ifdef CONFIG_CRYPTO_DEV_SP_PSP
        psp_pci_exit();
#endif

        sp_pci_exit();
#endif

#ifdef CONFIG_ARM64
        sp_platform_exit();
#endif
}

module_init(sp_mod_init);
module_exit(sp_mod_exit);