// SPDX-License-Identifier: GPL-2.0
/*
 * Driver for FPGA Device Feature List (DFL) PCIe device
 *
 * Copyright (C) 2017-2018 Intel Corporation, Inc.
 *
 * Authors:
 *   Zhang Yi <Yi.Z.Zhang@intel.com>
 *   Xiao Guangrong <guangrong.xiao@linux.intel.com>
 *   Joseph Grecco <joe.grecco@intel.com>
 *   Enno Luebbers <enno.luebbers@intel.com>
 *   Tim Whisonant <tim.whisonant@intel.com>
 *   Ananda Ravuri <ananda.ravuri@intel.com>
 *   Henry Mitchel <henry.mitchel@intel.com>
 */

#include <linux/pci.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/stddef.h>
#include <linux/errno.h>
#include <linux/aer.h>

#include "dfl.h"

#define DRV_VERSION	"0.8"
#define DRV_NAME	"dfl-pci"

#define PCI_VSEC_ID_INTEL_DFLS 0x43

#define PCI_VNDR_DFLS_CNT 0x8
#define PCI_VNDR_DFLS_RES 0xc

#define PCI_VNDR_DFLS_RES_BAR_MASK GENMASK(2, 0)
#define PCI_VNDR_DFLS_RES_OFF_MASK GENMASK(31, 3)

struct cci_drvdata {
	struct dfl_fpga_cdev *cdev;	/* container device */
};

static void __iomem *cci_pci_ioremap_bar0(struct pci_dev *pcidev)
{
	if (pcim_iomap_regions(pcidev, BIT(0), DRV_NAME))
		return NULL;

	return pcim_iomap_table(pcidev)[0];
}

static int cci_pci_alloc_irq(struct pci_dev *pcidev)
{
	int ret, nvec = pci_msix_vec_count(pcidev);

	if (nvec <= 0) {
		dev_dbg(&pcidev->dev, "fpga interrupt not supported\n");
		return 0;
	}

	ret = pci_alloc_irq_vectors(pcidev, nvec, nvec, PCI_IRQ_MSIX);
	if (ret < 0)
		return ret;

	return nvec;
}

static void cci_pci_free_irq(struct pci_dev *pcidev)
{
	pci_free_irq_vectors(pcidev);
}

/* PCI Device ID */
#define PCIE_DEVICE_ID_PF_INT_5_X	0xBCBD
#define PCIE_DEVICE_ID_PF_INT_6_X	0xBCC0
#define PCIE_DEVICE_ID_PF_DSC_1_X	0x09C4
#define PCIE_DEVICE_ID_INTEL_PAC_N3000	0x0B30
/* VF Device */
#define PCIE_DEVICE_ID_VF_INT_5_X	0xBCBF
#define PCIE_DEVICE_ID_VF_INT_6_X	0xBCC1
#define PCIE_DEVICE_ID_VF_DSC_1_X	0x09C5

static struct pci_device_id cci_pcie_id_tbl[] = {
	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCIE_DEVICE_ID_PF_INT_5_X),},
	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCIE_DEVICE_ID_VF_INT_5_X),},
	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCIE_DEVICE_ID_PF_INT_6_X),},
	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCIE_DEVICE_ID_VF_INT_6_X),},
	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCIE_DEVICE_ID_PF_DSC_1_X),},
	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCIE_DEVICE_ID_VF_DSC_1_X),},
	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCIE_DEVICE_ID_INTEL_PAC_N3000),},
	{0,}
};
MODULE_DEVICE_TABLE(pci, cci_pcie_id_tbl);

static int cci_init_drvdata(struct pci_dev *pcidev)
{
	struct cci_drvdata *drvdata;

	drvdata = devm_kzalloc(&pcidev->dev, sizeof(*drvdata), GFP_KERNEL);
	if (!drvdata)
		return -ENOMEM;

	pci_set_drvdata(pcidev, drvdata);

	return 0;
}

static void cci_remove_feature_devs(struct pci_dev *pcidev)
{
	struct cci_drvdata *drvdata = pci_get_drvdata(pcidev);

	/* remove all children feature devices */
	dfl_fpga_feature_devs_remove(drvdata->cdev);
	cci_pci_free_irq(pcidev);
}

static int *cci_pci_create_irq_table(struct pci_dev *pcidev, unsigned int nvec)
{
	unsigned int i;
	int *table;

	table = kcalloc(nvec, sizeof(int), GFP_KERNEL);
	if (!table)
		return table;

	for (i = 0; i < nvec; i++)
		table[i] = pci_irq_vector(pcidev, i);

	return table;
}

static int find_dfls_by_vsec(struct pci_dev *pcidev, struct dfl_fpga_enum_info *info)
{
	u32 bir, offset, vndr_hdr, dfl_cnt, dfl_res;
	int dfl_res_off, i, bars, voff = 0;
	resource_size_t start, len;

	while ((voff = pci_find_next_ext_capability(pcidev, voff, PCI_EXT_CAP_ID_VNDR))) {
		vndr_hdr = 0;
		pci_read_config_dword(pcidev, voff + PCI_VNDR_HEADER, &vndr_hdr);

		if (PCI_VNDR_HEADER_ID(vndr_hdr) == PCI_VSEC_ID_INTEL_DFLS &&
		    pcidev->vendor == PCI_VENDOR_ID_INTEL)
			break;
	}

	if (!voff) {
		dev_dbg(&pcidev->dev, "%s no DFL VSEC found\n", __func__);
		return -ENODEV;
	}

	dfl_cnt = 0;
	pci_read_config_dword(pcidev, voff + PCI_VNDR_DFLS_CNT, &dfl_cnt);
	if (dfl_cnt > PCI_STD_NUM_BARS) {
		dev_err(&pcidev->dev, "%s too many DFLs %d > %d\n",
			__func__, dfl_cnt, PCI_STD_NUM_BARS);
		return -EINVAL;
	}

	dfl_res_off = voff + PCI_VNDR_DFLS_RES;
	if (dfl_res_off + (dfl_cnt * sizeof(u32)) > PCI_CFG_SPACE_EXP_SIZE) {
		dev_err(&pcidev->dev, "%s DFL VSEC too big for PCIe config space\n",
			__func__);
		return -EINVAL;
	}

	for (i = 0, bars = 0; i < dfl_cnt; i++, dfl_res_off += sizeof(u32)) {
		dfl_res = GENMASK(31, 0);
		pci_read_config_dword(pcidev, dfl_res_off, &dfl_res);

		bir = dfl_res & PCI_VNDR_DFLS_RES_BAR_MASK;
		if (bir >= PCI_STD_NUM_BARS) {
			dev_err(&pcidev->dev, "%s bad bir number %d\n",
				__func__, bir);
			return -EINVAL;
		}

		if (bars & BIT(bir)) {
			dev_err(&pcidev->dev, "%s DFL for BAR %d already specified\n",
				__func__, bir);
			return -EINVAL;
		}

		bars |= BIT(bir);

		len = pci_resource_len(pcidev, bir);
		offset = dfl_res & PCI_VNDR_DFLS_RES_OFF_MASK;
		if (offset >= len) {
			dev_err(&pcidev->dev, "%s bad offset %u >= %pa\n",
				__func__, offset, &len);
			return -EINVAL;
		}

		dev_dbg(&pcidev->dev, "%s BAR %d offset 0x%x\n", __func__, bir, offset);

		len -= offset;

		start = pci_resource_start(pcidev, bir) + offset;

		dfl_fpga_enum_info_add_dfl(info, start, len);
	}

	return 0;
}

/* default method of finding dfls starting at offset 0 of bar 0 */
static int find_dfls_by_default(struct pci_dev *pcidev,
				struct dfl_fpga_enum_info *info)
{
	int port_num, bar, i, ret = 0;
	resource_size_t start, len;
	void __iomem *base;
	u32 offset;
	u64 v;

	/* start to find Device Feature List from Bar 0 */
	base = cci_pci_ioremap_bar0(pcidev);
	if (!base)
		return -ENOMEM;

	/*
	 * PF device has FME and Ports/AFUs, and VF device only has one
	 * Port/AFU. Check them and add related "Device Feature List" info
	 * for the next step enumeration.
	 */
	if (dfl_feature_is_fme(base)) {
		start = pci_resource_start(pcidev, 0);
		len = pci_resource_len(pcidev, 0);

		dfl_fpga_enum_info_add_dfl(info, start, len);

		/*
		 * find more Device Feature Lists (e.g. Ports) per information
		 * indicated by FME module.
		 */
		v = readq(base + FME_HDR_CAP);
		port_num = FIELD_GET(FME_CAP_NUM_PORTS, v);

		WARN_ON(port_num > MAX_DFL_FPGA_PORT_NUM);

		for (i = 0; i < port_num; i++) {
			v = readq(base + FME_HDR_PORT_OFST(i));

			/* skip ports which are not implemented. */
			if (!(v & FME_PORT_OFST_IMP))
				continue;

			/*
			 * add Port's Device Feature List information for next
			 * step enumeration.
			 */
			bar = FIELD_GET(FME_PORT_OFST_BAR_ID, v);
			offset = FIELD_GET(FME_PORT_OFST_DFH_OFST, v);
			start = pci_resource_start(pcidev, bar) + offset;
			len = pci_resource_len(pcidev, bar) - offset;

			dfl_fpga_enum_info_add_dfl(info, start, len);
		}
	} else if (dfl_feature_is_port(base)) {
		start = pci_resource_start(pcidev, 0);
		len = pci_resource_len(pcidev, 0);

		dfl_fpga_enum_info_add_dfl(info, start, len);
	} else {
		ret = -ENODEV;
	}

	/* release I/O mappings for next step enumeration */
	pcim_iounmap_regions(pcidev, BIT(0));

	return ret;
}

/* enumerate feature devices under pci device */
static int cci_enumerate_feature_devs(struct pci_dev *pcidev)
{
	struct cci_drvdata *drvdata = pci_get_drvdata(pcidev);
	struct dfl_fpga_enum_info *info;
	struct dfl_fpga_cdev *cdev;
	int nvec, ret = 0;
	int *irq_table;

	/* allocate enumeration info via pci_dev */
	info = dfl_fpga_enum_info_alloc(&pcidev->dev);
	if (!info)
		return -ENOMEM;

	/* add irq info for enumeration if the device support irq */
	nvec = cci_pci_alloc_irq(pcidev);
	if (nvec < 0) {
		dev_err(&pcidev->dev, "Fail to alloc irq %d.\n", nvec);
		ret = nvec;
		goto enum_info_free_exit;
	} else if (nvec) {
		irq_table = cci_pci_create_irq_table(pcidev, nvec);
		if (!irq_table) {
			ret = -ENOMEM;
			goto irq_free_exit;
		}

		ret = dfl_fpga_enum_info_add_irq(info, nvec, irq_table);
		kfree(irq_table);
		if (ret)
			goto irq_free_exit;
	}

	ret = find_dfls_by_vsec(pcidev, info);
	if (ret == -ENODEV)
		ret = find_dfls_by_default(pcidev, info);

	if (ret)
		goto irq_free_exit;

	/* start enumeration with prepared enumeration information */
	cdev = dfl_fpga_feature_devs_enumerate(info);
	if (IS_ERR(cdev)) {
		dev_err(&pcidev->dev, "Enumeration failure\n");
		ret = PTR_ERR(cdev);
		goto irq_free_exit;
	}

	drvdata->cdev = cdev;

irq_free_exit:
	if (ret)
		cci_pci_free_irq(pcidev);
enum_info_free_exit:
	dfl_fpga_enum_info_free(info);

	return ret;
}

static
int cci_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *pcidevid)
{
	int ret;

	ret = pcim_enable_device(pcidev);
	if (ret < 0) {
		dev_err(&pcidev->dev, "Failed to enable device %d.\n", ret);
		return ret;
	}

	ret = pci_enable_pcie_error_reporting(pcidev);
	if (ret && ret != -EINVAL)
		dev_info(&pcidev->dev, "PCIE AER unavailable %d.\n", ret);

	pci_set_master(pcidev);

	if (!pci_set_dma_mask(pcidev, DMA_BIT_MASK(64))) {
		ret = pci_set_consistent_dma_mask(pcidev, DMA_BIT_MASK(64));
		if (ret)
			goto disable_error_report_exit;
	} else if (!pci_set_dma_mask(pcidev, DMA_BIT_MASK(32))) {
		ret = pci_set_consistent_dma_mask(pcidev, DMA_BIT_MASK(32));
		if (ret)
			goto disable_error_report_exit;
	} else {
		ret = -EIO;
		dev_err(&pcidev->dev, "No suitable DMA support available.\n");
		goto disable_error_report_exit;
	}

	ret = cci_init_drvdata(pcidev);
	if (ret) {
		dev_err(&pcidev->dev, "Fail to init drvdata %d.\n", ret);
		goto disable_error_report_exit;
	}

	ret = cci_enumerate_feature_devs(pcidev);
	if (!ret)
		return ret;

	dev_err(&pcidev->dev, "enumeration failure %d.\n", ret);

disable_error_report_exit:
	pci_disable_pcie_error_reporting(pcidev);
	return ret;
}

static int cci_pci_sriov_configure(struct pci_dev *pcidev, int num_vfs)
{
	struct cci_drvdata *drvdata = pci_get_drvdata(pcidev);
	struct dfl_fpga_cdev *cdev = drvdata->cdev;

	if (!num_vfs) {
		/*
		 * disable SRIOV and then put released ports back to default
		 * PF access mode.
		 */
		pci_disable_sriov(pcidev);

		dfl_fpga_cdev_config_ports_pf(cdev);

	} else {
		int ret;

		/*
		 * before enable SRIOV, put released ports into VF access mode
		 * first of all.
		 */
		ret = dfl_fpga_cdev_config_ports_vf(cdev, num_vfs);
		if (ret)
			return ret;

		ret = pci_enable_sriov(pcidev, num_vfs);
		if (ret) {
			dfl_fpga_cdev_config_ports_pf(cdev);
			return ret;
		}
	}

	return num_vfs;
}

static void cci_pci_remove(struct pci_dev *pcidev)
{
	if (dev_is_pf(&pcidev->dev))
		cci_pci_sriov_configure(pcidev, 0);

	cci_remove_feature_devs(pcidev);
	pci_disable_pcie_error_reporting(pcidev);
}

static struct pci_driver cci_pci_driver = {
	.name = DRV_NAME,
	.id_table = cci_pcie_id_tbl,
	.probe = cci_pci_probe,
	.remove = cci_pci_remove,
	.sriov_configure = cci_pci_sriov_configure,
};

module_pci_driver(cci_pci_driver);

MODULE_DESCRIPTION("FPGA DFL PCIe Device Driver");
MODULE_AUTHOR("Intel Corporation");
MODULE_LICENSE("GPL v2");