alistair23-linux/drivers/pci/controller/dwc/pci-imx6-ep.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright 2019 NXP
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>

#define DRV_DESCRIPTION	"i.MX PCIE endpoint device driver"
#define DRV_VERSION	"version 0.1"
#define DRV_NAME	"imx_pcie_ep"

struct imx_pcie_ep_priv {
	struct pci_dev *pci_dev;
};

/**
 * imx_pcie_ep_probe - Device Initialization Routine
 * @pdev: PCI device information struct
 * @id: entry in id_tbl
 *
 * Returns 0 on success, negative on failure
 **/
static int imx_pcie_ep_probe(struct pci_dev *pdev,
		const struct pci_device_id *id)
{
	int ret = 0, index = 0, found = 0;
	unsigned int hard_wired = 0, msi_addr = 0, local_addr;
	struct resource cfg_res;
	const char *name = NULL;
	struct device_node *np = NULL;
	struct device *dev = &pdev->dev;
	struct imx_pcie_ep_priv *priv;

	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->pci_dev = pdev;
	if (pci_enable_device(pdev)) {
		ret = -ENODEV;
		goto out;
	}
	pci_set_master(pdev);
	pci_set_drvdata(pdev, priv);

	ret = pci_enable_msi(priv->pci_dev);
	if (ret < 0) {
		dev_err(dev, "can't enable msi\n");
		goto err_pci_unmap_mmio;
	}

	/* Use the first none-hard-wired port as ep */
	while ((np = of_find_node_by_type(np, "pci"))) {
		if (!of_device_is_available(np))
			continue;
		if (of_property_read_u32(np, "hard-wired", &hard_wired)) {
			if (hard_wired == 0)
				break;
		}
	}
	if (of_property_read_u32(np, "local-addr", &local_addr))
		local_addr = 0;

	while (!of_property_read_string_index(np, "reg-names", index, &name)) {
		if (strcmp("config", name)) {
			index++;
			continue;
		}
		found = 1;
		break;
	}

	if (!found) {
		dev_err(dev, "can't find config reg space.\n");
		ret = -EINVAL;
		goto err_pci_disable_msi;
	}

	ret = of_address_to_resource(np, index, &cfg_res);
	if (ret) {
		dev_err(dev, "can't get cfg_res.\n");
		ret = -EINVAL;
		goto err_pci_disable_msi;
	} else {
		msi_addr = cfg_res.start + resource_size(&cfg_res);
	}

	pr_info("msi_addr 0x%08x, local_addr 0x%08x\n", msi_addr, local_addr);
	pci_bus_write_config_dword(pdev->bus, 0, 0x54, msi_addr);
	if (local_addr) {
		msi_addr = msi_addr & 0xFFFFFFF;
		msi_addr |= (local_addr & 0xF0000000);
	}
	pci_bus_write_config_dword(pdev->bus->parent, 0, 0x820, msi_addr);
	/* configure rc's msi cap */
	pci_bus_read_config_dword(pdev->bus->parent, 0, 0x50, &ret);
	ret |= (PCI_MSI_FLAGS_ENABLE << 16);
	pci_bus_write_config_dword(pdev->bus->parent, 0, 0x50, ret);
	pci_bus_write_config_dword(pdev->bus->parent, 0, 0x828, 0x1);
	pci_bus_write_config_dword(pdev->bus->parent, 0, 0x82C, 0xFFFFFFFE);

	return 0;

err_pci_disable_msi:
	pci_disable_msi(pdev);
err_pci_unmap_mmio:
	pci_disable_device(pdev);
out:
	kfree(priv);
	return ret;
}

static void imx_pcie_ep_remove(struct pci_dev *pdev)
{
	struct imx_pcie_ep_priv *priv = pci_get_drvdata(pdev);

	if (!priv)
		return;
	pr_info("***imx pcie ep driver unload***\n");
}

static struct pci_device_id imx_pcie_ep_ids[] = {
	{
	.class =	PCI_CLASS_MEMORY_RAM << 8,
	.class_mask =	~0,
	.vendor =	0xbeaf,
	.device =	0xdead,
	.subvendor =	PCI_ANY_ID,
	.subdevice =	PCI_ANY_ID,
	},
	{ }	/* terminate list */
};
MODULE_DEVICE_TABLE(pci, imx_pcie_ep_ids);

static struct pci_driver imx_pcie_ep_driver = {
	.name = DRV_NAME,
	.id_table = imx_pcie_ep_ids,
	.probe = imx_pcie_ep_probe,
	.remove = imx_pcie_ep_remove,
};

static int __init imx_pcie_ep_init(void)
{
	int ret;

	pr_info(DRV_DESCRIPTION ", " DRV_VERSION "\n");
	ret = pci_register_driver(&imx_pcie_ep_driver);
	if (ret)
		pr_err("Unable to initialize PCI module\n");

	return ret;
}

static void __exit imx_pcie_ep_exit(void)
{
	pci_unregister_driver(&imx_pcie_ep_driver);
}

module_exit(imx_pcie_ep_exit);
module_init(imx_pcie_ep_init);

MODULE_DESCRIPTION(DRV_DESCRIPTION);
MODULE_VERSION(DRV_VERSION);
MODULE_LICENSE("GPL");
MODULE_ALIAS("imx_pcie_ep");