drivers/char/xillybus/xillybus_pcie.c

// 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_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);