// SPDX-License-Identifier: GPL-2.0-only
/*
 * AMD Passthru DMA device driver
 * -- Based on the CCP driver
 *
 * Copyright (C) 2016,2021 Advanced Micro Devices, Inc.
 *
 * Author: Sanjay R Mehta <sanju.mehta@amd.com>
 * Author: Tom Lendacky <thomas.lendacky@amd.com>
 * Author: Gary R Hook <gary.hook@amd.com>
 */

#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/pci_ids.h>
#include <linux/pci.h>
#include <linux/spinlock.h>

#include "ptdma.h"

struct pt_msix {
        int msix_count;
        struct msix_entry msix_entry;
};

/*
 * pt_alloc_struct - allocate and initialize the pt_device struct
 *
 * @dev: device struct of the PTDMA
 */
static struct pt_device *pt_alloc_struct(struct device *dev)
{
        struct pt_device *pt;

        pt = devm_kzalloc(dev, sizeof(*pt), GFP_KERNEL);

        if (!pt)
                return NULL;
        pt->dev = dev;

        INIT_LIST_HEAD(&pt->cmd);

        return pt;
}

static int pt_get_msix_irqs(struct pt_device *pt)
{
        struct pt_msix *pt_msix = pt->pt_msix;
        struct device *dev = pt->dev;
        struct pci_dev *pdev = to_pci_dev(dev);
        int ret;

        pt_msix->msix_entry.entry = 0;

        ret = pci_enable_msix_range(pdev, &pt_msix->msix_entry, 1, 1);
        if (ret < 0)
                return ret;

        pt_msix->msix_count = ret;

        pt->pt_irq = pt_msix->msix_entry.vector;

        return 0;
}

static int pt_get_msi_irq(struct pt_device *pt)
{
        struct device *dev = pt->dev;
        struct pci_dev *pdev = to_pci_dev(dev);
        int ret;

        ret = pci_enable_msi(pdev);
        if (ret)
                return ret;

        pt->pt_irq = pdev->irq;

        return 0;
}

static int pt_get_irqs(struct pt_device *pt)
{
        struct device *dev = pt->dev;
        int ret;

        ret = pt_get_msix_irqs(pt);
        if (!ret)
                return 0;

        /* Couldn't get MSI-X vectors, try MSI */
        dev_err(dev, "could not enable MSI-X (%d), trying MSI\n", ret);
        ret = pt_get_msi_irq(pt);
        if (!ret)
                return 0;

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

        return ret;
}

static void pt_free_irqs(struct pt_device *pt)
{
        struct pt_msix *pt_msix = pt->pt_msix;
        struct device *dev = pt->dev;
        struct pci_dev *pdev = to_pci_dev(dev);

        if (pt_msix->msix_count)
                pci_disable_msix(pdev);
        else if (pt->pt_irq)
                pci_disable_msi(pdev);

        pt->pt_irq = 0;
}

static int pt_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
        struct pt_device *pt;
        struct pt_msix *pt_msix;
        struct device *dev = &pdev->dev;
        void __iomem * const *iomap_table;
        int bar_mask;
        int ret = -ENOMEM;

        pt = pt_alloc_struct(dev);
        if (!pt)
                goto e_err;

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

        pt->pt_msix = pt_msix;
        pt->dev_vdata = (struct pt_dev_vdata *)id->driver_data;
        if (!pt->dev_vdata) {
                ret = -ENODEV;
                dev_err(dev, "missing driver data\n");
                goto e_err;
        }

        ret = pcim_enable_device(pdev);
        if (ret) {
                dev_err(dev, "pcim_enable_device failed (%d)\n", ret);
                goto e_err;
        }

        bar_mask = pci_select_bars(pdev, IORESOURCE_MEM);
        ret = pcim_iomap_regions(pdev, bar_mask, "ptdma");
        if (ret) {
                dev_err(dev, "pcim_iomap_regions failed (%d)\n", ret);
                goto e_err;
        }

        iomap_table = pcim_iomap_table(pdev);
        if (!iomap_table) {
                dev_err(dev, "pcim_iomap_table failed\n");
                ret = -ENOMEM;
                goto e_err;
        }

        pt->io_regs = iomap_table[pt->dev_vdata->bar];
        if (!pt->io_regs) {
                dev_err(dev, "ioremap failed\n");
                ret = -ENOMEM;
                goto e_err;
        }

        ret = pt_get_irqs(pt);
        if (ret)
                goto e_err;

        pci_set_master(pdev);

        ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(48));
        if (ret) {
                ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
                if (ret) {
                        dev_err(dev, "dma_set_mask_and_coherent failed (%d)\n",
                                ret);
                        goto e_err;
                }
        }

        dev_set_drvdata(dev, pt);

        if (pt->dev_vdata)
                ret = pt_core_init(pt);

        if (ret)
                goto e_err;

        return 0;

e_err:
        dev_err(dev, "initialization failed ret = %d\n", ret);

        return ret;
}

static void pt_pci_remove(struct pci_dev *pdev)
{
        struct device *dev = &pdev->dev;
        struct pt_device *pt = dev_get_drvdata(dev);

        if (!pt)
                return;

        if (pt->dev_vdata)
                pt_core_destroy(pt);

        pt_free_irqs(pt);
}

static const struct pt_dev_vdata dev_vdata[] = {
        {
                .bar = 2,
        },
};

static const struct pci_device_id pt_pci_table[] = {
        { PCI_VDEVICE(AMD, 0x1498), (kernel_ulong_t)&dev_vdata[0] },
        /* Last entry must be zero */
        { 0, }
};
MODULE_DEVICE_TABLE(pci, pt_pci_table);

static struct pci_driver pt_pci_driver = {
        .name = "ptdma",
        .id_table = pt_pci_table,
        .probe = pt_pci_probe,
        .remove = pt_pci_remove,
};

module_pci_driver(pt_pci_driver);

MODULE_AUTHOR("Sanjay R Mehta <sanju.mehta@amd.com>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("AMD PassThru DMA driver");