// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/drivers/misc/xillybus_pcie.c
 *
 * Copyright 2011 Xillybus Ltd, http://xillybus.com
 *
 * Driver for the Xillybus FPGA/host framework using PCI Express.
 */

#include <linux/module.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include "xillybus.h"

MODULE_DESCRIPTION("Xillybus driver for PCIe");
MODULE_AUTHOR("Eli Billauer, Xillybus Ltd.");
MODULE_VERSION("1.06");
MODULE_ALIAS("xillybus_pcie");
MODULE_LICENSE("GPL v2");

#define PCI_DEVICE_ID_XILLYBUS          0xebeb

#define PCI_VENDOR_ID_ACTEL             0x11aa
#define PCI_VENDOR_ID_LATTICE           0x1204

static const char xillyname[] = "xillybus_pcie";

static const struct pci_device_id xillyids[] = {
        {PCI_DEVICE(PCI_VENDOR_ID_XILINX, PCI_DEVICE_ID_XILLYBUS)},
        {PCI_DEVICE(PCI_VENDOR_ID_ALTERA, PCI_DEVICE_ID_XILLYBUS)},
        {PCI_DEVICE(PCI_VENDOR_ID_ACTEL, PCI_DEVICE_ID_XILLYBUS)},
        {PCI_DEVICE(PCI_VENDOR_ID_LATTICE, PCI_DEVICE_ID_XILLYBUS)},
        { /* End: all zeroes */ }
};

static int xilly_pci_direction(int direction)
{
        switch (direction) {
        case DMA_TO_DEVICE:
                return PCI_DMA_TODEVICE;
        case DMA_FROM_DEVICE:
                return PCI_DMA_FROMDEVICE;
        default:
                return PCI_DMA_BIDIRECTIONAL;
        }
}

static void xilly_dma_sync_single_for_cpu_pci(struct xilly_endpoint *ep,
                                              dma_addr_t dma_handle,
                                              size_t size,
                                              int direction)
{
        pci_dma_sync_single_for_cpu(ep->pdev,
                                    dma_handle,
                                    size,
                                    xilly_pci_direction(direction));
}

static void xilly_dma_sync_single_for_device_pci(struct xilly_endpoint *ep,
                                                 dma_addr_t dma_handle,
                                                 size_t size,
                                                 int direction)
{
        pci_dma_sync_single_for_device(ep->pdev,
                                       dma_handle,
                                       size,
                                       xilly_pci_direction(direction));
}

static void xilly_pci_unmap(void *ptr)
{
        struct xilly_mapping *data = ptr;

        pci_unmap_single(data->device, data->dma_addr,
                         data->size, data->direction);

        kfree(ptr);
}

/*
 * Map either through the PCI DMA mapper or the non_PCI one. Behind the
 * scenes exactly the same functions are called with the same parameters,
 * but that can change.
 */

static int xilly_map_single_pci(struct xilly_endpoint *ep,
                                void *ptr,
                                size_t size,
                                int direction,
                                dma_addr_t *ret_dma_handle
        )
{
        int pci_direction;
        dma_addr_t addr;
        struct xilly_mapping *this;

        this = kzalloc(sizeof(*this), GFP_KERNEL);
        if (!this)
                return -ENOMEM;

        pci_direction = xilly_pci_direction(direction);

        addr = pci_map_single(ep->pdev, ptr, size, pci_direction);

        if (pci_dma_mapping_error(ep->pdev, addr)) {
                kfree(this);
                return -ENODEV;
        }

        this->device = ep->pdev;
        this->dma_addr = addr;
        this->size = size;
        this->direction = pci_direction;

        *ret_dma_handle = addr;

        return devm_add_action_or_reset(ep->dev, xilly_pci_unmap, this);
}

static struct xilly_endpoint_hardware pci_hw = {
        .owner = THIS_MODULE,
        .hw_sync_sgl_for_cpu = xilly_dma_sync_single_for_cpu_pci,
        .hw_sync_sgl_for_device = xilly_dma_sync_single_for_device_pci,
        .map_single = xilly_map_single_pci,
};

static int xilly_probe(struct pci_dev *pdev,
                       const struct pci_device_id *ent)
{
        struct xilly_endpoint *endpoint;
        int rc;

        endpoint = xillybus_init_endpoint(pdev, &pdev->dev, &pci_hw);

        if (!endpoint)
                return -ENOMEM;

        pci_set_drvdata(pdev, endpoint);

        rc = pcim_enable_device(pdev);
        if (rc) {
                dev_err(endpoint->dev,
                        "pcim_enable_device() failed. Aborting.\n");
                return rc;
        }

        /* L0s has caused packet drops. No power saving, thank you. */

        pci_disable_link_state(pdev, PCIE_LINK_STATE_L0S);

        if (!(pci_resource_flags(pdev, 0) & IORESOURCE_MEM)) {
                dev_err(endpoint->dev,
                        "Incorrect BAR configuration. Aborting.\n");
                return -ENODEV;
        }

        rc = pcim_iomap_regions(pdev, 0x01, xillyname);
        if (rc) {
                dev_err(endpoint->dev,
                        "pcim_iomap_regions() failed. Aborting.\n");
                return rc;
        }

        endpoint->registers = pcim_iomap_table(pdev)[0];

        pci_set_master(pdev);

        /* Set up a single MSI interrupt */
        if (pci_enable_msi(pdev)) {
                dev_err(endpoint->dev,
                        "Failed to enable MSI interrupts. Aborting.\n");
                return -ENODEV;
        }
        rc = devm_request_irq(&pdev->dev, pdev->irq, xillybus_isr, 0,
                              xillyname, endpoint);
        if (rc) {
                dev_err(endpoint->dev,
                        "Failed to register MSI handler. Aborting.\n");
                return -ENODEV;
        }

        /*
         * Some (old and buggy?) hardware drops 64-bit addressed PCIe packets,
         * even when the PCIe driver claims that a 64-bit mask is OK. On the
         * other hand, on some architectures, 64-bit addressing is mandatory.
         * So go for the 64-bit mask only when failing is the other option.
         */

        if (!pci_set_dma_mask(pdev, DMA_BIT_MASK(32))) {
                endpoint->dma_using_dac = 0;
        } else if (!pci_set_dma_mask(pdev, DMA_BIT_MASK(64))) {
                endpoint->dma_using_dac = 1;
        } else {
                dev_err(endpoint->dev, "Failed to set DMA mask. Aborting.\n");
                return -ENODEV;
        }

        return xillybus_endpoint_discovery(endpoint);
}

static void xilly_remove(struct pci_dev *pdev)
{
        struct xilly_endpoint *endpoint = pci_get_drvdata(pdev);

        xillybus_endpoint_remove(endpoint);
}

MODULE_DEVICE_TABLE(pci, xillyids);

static struct pci_driver xillybus_driver = {
        .name = xillyname,
        .id_table = xillyids,
        .probe = xilly_probe,
        .remove = xilly_remove,
};

module_pci_driver(xillybus_driver);