/*
 * AMD Cryptographic Coprocessor (CCP) driver
 *
 * Copyright (C) 2014 Advanced Micro Devices, Inc.
 *
 * Author: Tom Lendacky <thomas.lendacky@amd.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/ioport.h>
#include <linux/dma-mapping.h>
#include <linux/kthread.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
#include <linux/ccp.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/acpi.h>

#include "ccp-dev.h"

struct ccp_platform {
        int use_acpi;
        int coherent;
};

static int ccp_get_irq(struct ccp_device *ccp)
{
        struct device *dev = ccp->dev;
        struct platform_device *pdev = container_of(dev,
                                        struct platform_device, dev);
        int ret;

        ret = platform_get_irq(pdev, 0);
        if (ret < 0)
                return ret;

        ccp->irq = ret;
        ret = request_irq(ccp->irq, ccp_irq_handler, 0, "ccp", dev);
        if (ret) {
                dev_notice(dev, "unable to allocate IRQ (%d)\n", ret);
                return ret;
        }

        return 0;
}

static int ccp_get_irqs(struct ccp_device *ccp)
{
        struct device *dev = ccp->dev;
        int ret;

        ret = ccp_get_irq(ccp);
        if (!ret)
                return 0;

        /* Couldn't get an interrupt */
        dev_notice(dev, "could not enable interrupts (%d)\n", ret);

        return ret;
}

static void ccp_free_irqs(struct ccp_device *ccp)
{
        struct device *dev = ccp->dev;

        free_irq(ccp->irq, dev);
}

static struct resource *ccp_find_mmio_area(struct ccp_device *ccp)
{
        struct device *dev = ccp->dev;
        struct platform_device *pdev = container_of(dev,
                                        struct platform_device, dev);
        struct resource *ior;

        ior = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (ior && (resource_size(ior) >= 0x800))
                return ior;

        return NULL;
}

static int ccp_platform_probe(struct platform_device *pdev)
{
        struct ccp_device *ccp;
        struct ccp_platform *ccp_platform;
        struct device *dev = &pdev->dev;
        struct acpi_device *adev = ACPI_COMPANION(dev);
        struct resource *ior;
        int ret;

        ret = -ENOMEM;
        ccp = ccp_alloc_struct(dev);
        if (!ccp)
                goto e_err;

        ccp_platform = devm_kzalloc(dev, sizeof(*ccp_platform), GFP_KERNEL);
        if (!ccp_platform)
                goto e_err;

        ccp->dev_specific = ccp_platform;
        ccp->get_irq = ccp_get_irqs;
        ccp->free_irq = ccp_free_irqs;

        ccp_platform->use_acpi = (!adev || acpi_disabled) ? 0 : 1;

        ior = ccp_find_mmio_area(ccp);
        ccp->io_map = devm_ioremap_resource(dev, ior);
        if (IS_ERR(ccp->io_map)) {
                ret = PTR_ERR(ccp->io_map);
                goto e_err;
        }
        ccp->io_regs = ccp->io_map;

        ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(48));
        if (ret) {
                dev_err(dev, "dma_set_mask_and_coherent failed (%d)\n", ret);
                goto e_err;
        }

        ccp_platform->coherent = device_dma_is_coherent(ccp->dev);
        if (ccp_platform->coherent)
                ccp->axcache = CACHE_WB_NO_ALLOC;
        else
                ccp->axcache = CACHE_NONE;

        dev_set_drvdata(dev, ccp);

        ret = ccp_init(ccp);
        if (ret)
                goto e_err;

        dev_notice(dev, "enabled\n");

        return 0;

e_err:
        dev_notice(dev, "initialization failed\n");
        return ret;
}

static int ccp_platform_remove(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct ccp_device *ccp = dev_get_drvdata(dev);

        ccp_destroy(ccp);

        dev_notice(dev, "disabled\n");

        return 0;
}

#ifdef CONFIG_PM
static int ccp_platform_suspend(struct platform_device *pdev,
                                pm_message_t state)
{
        struct device *dev = &pdev->dev;
        struct ccp_device *ccp = dev_get_drvdata(dev);
        unsigned long flags;
        unsigned int i;

        spin_lock_irqsave(&ccp->cmd_lock, flags);

        ccp->suspending = 1;

        /* Wake all the queue kthreads to prepare for suspend */
        for (i = 0; i < ccp->cmd_q_count; i++)
                wake_up_process(ccp->cmd_q[i].kthread);

        spin_unlock_irqrestore(&ccp->cmd_lock, flags);

        /* Wait for all queue kthreads to say they're done */
        while (!ccp_queues_suspended(ccp))
                wait_event_interruptible(ccp->suspend_queue,
                                         ccp_queues_suspended(ccp));

        return 0;
}

static int ccp_platform_resume(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct ccp_device *ccp = dev_get_drvdata(dev);
        unsigned long flags;
        unsigned int i;

        spin_lock_irqsave(&ccp->cmd_lock, flags);

        ccp->suspending = 0;

        /* Wake up all the kthreads */
        for (i = 0; i < ccp->cmd_q_count; i++) {
                ccp->cmd_q[i].suspended = 0;
                wake_up_process(ccp->cmd_q[i].kthread);
        }

        spin_unlock_irqrestore(&ccp->cmd_lock, flags);

        return 0;
}
#endif

#ifdef CONFIG_ACPI
static const struct acpi_device_id ccp_acpi_match[] = {
        { "AMDI0C00", 0 },
        { },
};
MODULE_DEVICE_TABLE(acpi, ccp_acpi_match);
#endif

#ifdef CONFIG_OF
static const struct of_device_id ccp_of_match[] = {
        { .compatible = "amd,ccp-seattle-v1a" },
        { },
};
MODULE_DEVICE_TABLE(of, ccp_of_match);
#endif

static struct platform_driver ccp_platform_driver = {
        .driver = {
                .name = "AMD Cryptographic Coprocessor",
#ifdef CONFIG_ACPI
                .acpi_match_table = ccp_acpi_match,
#endif
#ifdef CONFIG_OF
                .of_match_table = ccp_of_match,
#endif
        },
        .probe = ccp_platform_probe,
        .remove = ccp_platform_remove,
#ifdef CONFIG_PM
        .suspend = ccp_platform_suspend,
        .resume = ccp_platform_resume,
#endif
};

int ccp_platform_init(void)
{
        return platform_driver_register(&ccp_platform_driver);
}

void ccp_platform_exit(void)
{
        platform_driver_unregister(&ccp_platform_driver);
}