/*
 * linux/drivers/misc/xillybus_pcie.c
 *
 * Copyright 2011 Xillybus Ltd, http://xillybus.com
 *
 * Driver for the Xillybus FPGA/host framework using PCI Express.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the smems of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 */

#include <linux/module.h>
#include <linux/pci.h>
#include <linux/pci-aspm.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_ALTERA		0x1172
#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));
}

/*
 * 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 dma_addr_t xilly_map_single_pci(struct xilly_cleanup *mem,
				       struct xilly_endpoint *ep,
				       void *ptr,
				       size_t size,
				       int direction
	)
{

	dma_addr_t addr = 0;
	struct xilly_dma *this;
	int pci_direction;

	this = kmalloc(sizeof(struct xilly_dma), GFP_KERNEL);
	if (!this)
		return 0;

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

	if (pci_dma_mapping_error(ep->pdev, addr)) {
		kfree(this);
		return 0;
	}

	this->dma_addr = addr;
	this->pdev = ep->pdev;
	this->size = size;

	list_add_tail(&this->node, &mem->to_unmap);

	return addr;
}

static void xilly_unmap_single_pci(struct xilly_dma *entry)
{
	pci_unmap_single(entry->pdev,
			 entry->dma_addr,
			 entry->size,
			 entry->direction);
}

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,
	.unmap_single = xilly_unmap_single_pci
};

static int xilly_probe(struct pci_dev *pdev,
				 const struct pci_device_id *ent)
{
	struct xilly_endpoint *endpoint;
	int rc = 0;

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

	if (!endpoint)
		return -ENOMEM;

	pci_set_drvdata(pdev, endpoint);

	rc = pci_enable_device(pdev);

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

	pci_disable_link_state(pdev, PCIE_LINK_STATE_L0S);

	if (rc) {
		dev_err(endpoint->dev,
			"pci_enable_device() failed. Aborting.\n");
		goto no_enable;
	}

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

	rc = pci_request_regions(pdev, xillyname);
	if (rc) {
		dev_err(endpoint->dev,
			"pci_request_regions() failed. Aborting.\n");
		goto failed_request_regions;
	}

	endpoint->registers = pci_iomap(pdev, 0, 128);
	if (!endpoint->registers) {
		dev_err(endpoint->dev, "Failed to map BAR 0. Aborting.\n");
		rc = -EIO;
		goto failed_iomap0;
	}

	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");
		rc = -ENODEV;
		goto failed_enable_msi;
	}
	rc = request_irq(pdev->irq, xillybus_isr, 0, xillyname, endpoint);

	if (rc) {
		dev_err(endpoint->dev,
			"Failed to register MSI handler. Aborting.\n");
		rc = -ENODEV;
		goto failed_register_msi;
	}

	/*
	 * In theory, an attempt to set the DMA mask to 64 and dma_using_dac=1
	 * is the right thing. But some unclever PCIe drivers report it's OK
	 * when the hardware drops those 64-bit PCIe packets. So trust
	 * nobody and use 32 bits DMA addressing in any case.
	 */

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

	rc = xillybus_endpoint_discovery(endpoint);

	if (!rc)
		return 0;

failed_dmamask:
	free_irq(pdev->irq, endpoint);
failed_register_msi:
	pci_disable_msi(pdev);
failed_enable_msi:
	/* pci_clear_master(pdev); Nobody else seems to do this */
	pci_iounmap(pdev, endpoint->registers);
failed_iomap0:
	pci_release_regions(pdev);
failed_request_regions:
bad_bar:
	pci_disable_device(pdev);
no_enable:
	xillybus_do_cleanup(&endpoint->cleanup, endpoint);

	kfree(endpoint);
	return rc;
}

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

	xillybus_endpoint_remove(endpoint);

	free_irq(pdev->irq, endpoint);

	pci_disable_msi(pdev);
	pci_iounmap(pdev, endpoint->registers);
	pci_release_regions(pdev);
	pci_disable_device(pdev);

	xillybus_do_cleanup(&endpoint->cleanup, endpoint);

	kfree(endpoint);
}

MODULE_DEVICE_TABLE(pci, xillyids);

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

static int __init xillybus_pcie_init(void)
{
	return pci_register_driver(&xillybus_driver);
}

static void __exit xillybus_pcie_exit(void)
{
	pci_unregister_driver(&xillybus_driver);
}


module_init(xillybus_pcie_init);
module_exit(xillybus_pcie_exit);