/*

Copyright 2019-2021, The Regents of the University of California.
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

   1. Redistributions of source code must retain the above copyright notice,
      this list of conditions and the following disclaimer.

   2. Redistributions in binary form must reproduce the above copyright notice,
      this list of conditions and the following disclaimer in the documentation
      and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE REGENTS OF THE UNIVERSITY OF CALIFORNIA ''AS
IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE REGENTS OF THE UNIVERSITY OF CALIFORNIA OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
OF SUCH DAMAGE.

The views and conclusions contained in the software and documentation are those
of the authors and should not be interpreted as representing official policies,
either expressed or implied, of The Regents of the University of California.

*/

#include "mqnic.h"
#include <linux/module.h>
#include <linux/version.h>
#include <linux/delay.h>

#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 4, 0)
#include <linux/pci-aspm.h>
#endif

MODULE_DESCRIPTION("mqnic driver");
MODULE_AUTHOR("Alex Forencich");
MODULE_LICENSE("Dual MIT/GPL");
MODULE_VERSION(DRIVER_VERSION);

static const struct pci_device_id mqnic_pci_id_table[] = {
	{PCI_DEVICE(0x1234, 0x1001)},
	{PCI_DEVICE(0x5543, 0x1001)},
	{0 /* end */ }
};

MODULE_DEVICE_TABLE(pci, mqnic_pci_id_table);

static LIST_HEAD(mqnic_devices);
static DEFINE_SPINLOCK(mqnic_devices_lock);

static unsigned int mqnic_get_free_id(void)
{
	struct mqnic_dev *mqnic;
	unsigned int id = 0;
	bool available = false;

	while (!available) {
		available = true;
		list_for_each_entry(mqnic, &mqnic_devices, dev_list_node) {
			if (mqnic->id == id) {
				available = false;
				id++;
				break;
			}
		}
	}

	return id;
}

static irqreturn_t mqnic_interrupt(int irq, void *data)
{
	struct mqnic_dev *mqnic = data;
	struct mqnic_priv *priv;

	int k, l;

	for (k = 0; k < ARRAY_SIZE(mqnic->ndev); k++) {
		if (unlikely(!mqnic->ndev[k]))
			continue;

		priv = netdev_priv(mqnic->ndev[k]);

		if (unlikely(!priv->port_up))
			continue;

		for (l = 0; l < priv->event_queue_count; l++) {
			if (unlikely(!priv->event_ring[l]))
				continue;

			if (priv->event_ring[l]->irq == irq) {
				mqnic_process_eq(priv->ndev, priv->event_ring[l]);
				mqnic_arm_eq(priv->event_ring[l]);
			}
		}
	}

	return IRQ_HANDLED;
}

static int mqnic_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
{
	int ret = 0;
	struct mqnic_dev *mqnic;
	struct device *dev = &pdev->dev;

	int k = 0;

	dev_info(dev, DRIVER_NAME " PCI probe");
	dev_info(dev, " Vendor: 0x%04x", pdev->vendor);
	dev_info(dev, " Device: 0x%04x", pdev->device);
	dev_info(dev, " Class: 0x%06x", pdev->class);
	dev_info(dev, " PCI ID: %04x:%02x:%02x.%d", pci_domain_nr(pdev->bus),
	         pdev->bus->number, PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
	if (pdev->pcie_cap) {
		u16 devctl;
		u32 lnkcap;
		u16 lnksta;
		pci_read_config_word(pdev, pdev->pcie_cap + PCI_EXP_DEVCTL, &devctl);
		pci_read_config_dword(pdev, pdev->pcie_cap + PCI_EXP_LNKCAP, &lnkcap);
		pci_read_config_word(pdev, pdev->pcie_cap + PCI_EXP_LNKSTA, &lnksta);
		dev_info(dev, " Max payload size: %d bytes",
		         128 << ((devctl & PCI_EXP_DEVCTL_PAYLOAD) >> 5));
		dev_info(dev, " Max read request size: %d bytes",
		         128 << ((devctl & PCI_EXP_DEVCTL_READRQ) >> 12));
		dev_info(dev, " Link capability: gen %d x%d",
		         lnkcap & PCI_EXP_LNKCAP_SLS, (lnkcap & PCI_EXP_LNKCAP_MLW) >> 4);
		dev_info(dev, " Link status: gen %d x%d",
		         lnksta & PCI_EXP_LNKSTA_CLS, (lnksta & PCI_EXP_LNKSTA_NLW) >> 4);
		dev_info(dev, " Relaxed ordering: %s",
		         devctl & PCI_EXP_DEVCTL_RELAX_EN ? "enabled" : "disabled");
		dev_info(dev, " Phantom functions: %s",
		         devctl & PCI_EXP_DEVCTL_PHANTOM ? "enabled" : "disabled");
		dev_info(dev, " Extended tags: %s",
		         devctl & PCI_EXP_DEVCTL_EXT_TAG ? "enabled" : "disabled");
		dev_info(dev, " No snoop: %s",
		         devctl & PCI_EXP_DEVCTL_NOSNOOP_EN ? "enabled" : "disabled");
	}
#ifdef CONFIG_NUMA
	dev_info(dev, " NUMA node: %d", pdev->dev.numa_node);
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 17, 0)
	pcie_print_link_status(pdev);
#endif

	mqnic = devm_kzalloc(dev, sizeof(*mqnic), GFP_KERNEL);
	if (!mqnic) {
		dev_err(dev, "Failed to allocate memory");
		return -ENOMEM;
	}

	mqnic->dev = dev;
	mqnic->pdev = pdev;
	pci_set_drvdata(pdev, mqnic);

	// assign ID and add to list
	spin_lock(&mqnic_devices_lock);
	mqnic->id = mqnic_get_free_id();
	list_add_tail(&mqnic->dev_list_node, &mqnic_devices);
	spin_unlock(&mqnic_devices_lock);

	snprintf(mqnic->name, sizeof(mqnic->name), DRIVER_NAME "%d", mqnic->id);

	// Disable ASPM
	pci_disable_link_state(pdev, PCIE_LINK_STATE_L0S |
	                       PCIE_LINK_STATE_L1 | PCIE_LINK_STATE_CLKPM);

	// Enable device
	ret = pci_enable_device_mem(pdev);
	if (ret) {
		dev_err(dev, "Failed to enable PCI device");
		goto fail_enable_device;
	}

	// Set mask
	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
	if (ret) {
		dev_warn(dev, "Warning: failed to set 64 bit PCI DMA mask");
		ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
		if (ret) {
			dev_err(dev, "Failed to set PCI DMA mask");
			goto fail_regions;
		}
	}

	// Set max segment size
	dma_set_max_seg_size(dev, DMA_BIT_MASK(32));

	// Reserve regions
	ret = pci_request_regions(pdev, DRIVER_NAME);
	if (ret) {
		dev_err(dev, "Failed to reserve regions");
		goto fail_regions;
	}

	mqnic->hw_regs_size = pci_resource_len(pdev, 0);
	mqnic->hw_regs_phys = pci_resource_start(pdev, 0);
	mqnic->app_hw_regs_size = pci_resource_len(pdev, 2);
	mqnic->app_hw_regs_phys = pci_resource_start(pdev, 2);
	mqnic->ram_hw_regs_size = pci_resource_len(pdev, 4);
	mqnic->ram_hw_regs_phys = pci_resource_start(pdev, 4);

	// Map BARs
	dev_info(dev, "Control BAR size: %llu", mqnic->hw_regs_size);
	mqnic->hw_addr = pci_ioremap_bar(pdev, 0);
	if (!mqnic->hw_addr) {
		ret = -ENOMEM;
		dev_err(dev, "Failed to map control BAR");
		goto fail_map_bars;
	}

	if (mqnic->app_hw_regs_size) {
		dev_info(dev, "Application BAR size: %llu", mqnic->app_hw_regs_size);
		mqnic->app_hw_addr = pci_ioremap_bar(pdev, 2);
		if (!mqnic->app_hw_addr) {
			ret = -ENOMEM;
			dev_err(dev, "Failed to map application BAR");
			goto fail_map_bars;
		}
	}

	if (mqnic->ram_hw_regs_size) {
		dev_info(dev, "RAM BAR size: %llu", mqnic->ram_hw_regs_size);
		mqnic->ram_hw_addr = pci_ioremap_bar(pdev, 4);
		if (!mqnic->ram_hw_addr) {
			ret = -ENOMEM;
			dev_err(dev, "Failed to map RAM BAR");
			goto fail_map_bars;
		}
	}

	// Check if device needs to be reset
	if (ioread32(mqnic->hw_addr) == 0xffffffff) {
		ret = -EIO;
		dev_err(dev, "Device needs to be reset");
		goto fail_map_bars;
	}

	// Read ID registers
	mqnic->fw_id = ioread32(mqnic->hw_addr + MQNIC_REG_FW_ID);
	dev_info(dev, "FW ID: 0x%08x", mqnic->fw_id);
	mqnic->fw_ver = ioread32(mqnic->hw_addr + MQNIC_REG_FW_VER);
	dev_info(dev, "FW version: %d.%d", mqnic->fw_ver >> 16, mqnic->fw_ver & 0xffff);
	mqnic->board_id = ioread32(mqnic->hw_addr + MQNIC_REG_BOARD_ID);
	dev_info(dev, "Board ID: 0x%08x", mqnic->board_id);
	mqnic->board_ver = ioread32(mqnic->hw_addr + MQNIC_REG_BOARD_VER);
	dev_info(dev, "Board version: %d.%d", mqnic->board_ver >> 16, mqnic->board_ver & 0xffff);

	mqnic->phc_count = ioread32(mqnic->hw_addr + MQNIC_REG_PHC_COUNT);
	dev_info(dev, "PHC count: %d", mqnic->phc_count);
	mqnic->phc_offset = ioread32(mqnic->hw_addr + MQNIC_REG_PHC_OFFSET);
	dev_info(dev, "PHC offset: 0x%08x", mqnic->phc_offset);

	if (mqnic->phc_count)
		mqnic->phc_hw_addr = mqnic->hw_addr + mqnic->phc_offset;

	mqnic->if_count = ioread32(mqnic->hw_addr + MQNIC_REG_IF_COUNT);
	dev_info(dev, "IF count: %d", mqnic->if_count);
	mqnic->if_stride = ioread32(mqnic->hw_addr + MQNIC_REG_IF_STRIDE);
	dev_info(dev, "IF stride: 0x%08x", mqnic->if_stride);
	mqnic->if_csr_offset = ioread32(mqnic->hw_addr + MQNIC_REG_IF_CSR_OFFSET);
	dev_info(dev, "IF CSR offset: 0x%08x", mqnic->if_csr_offset);

	// check BAR size
	if (mqnic->if_count * mqnic->if_stride > mqnic->hw_regs_size) {
		ret = -EIO;
		dev_err(dev, "Invalid BAR configuration (%d IF * 0x%x > 0x%llx)",
		        mqnic->if_count, mqnic->if_stride, mqnic->hw_regs_size);
		goto fail_map_bars;
	}

	// Allocate MSI IRQs
	mqnic->irq_count = pci_alloc_irq_vectors(pdev, 1, 32, PCI_IRQ_MSI);
	if (mqnic->irq_count < 0) {
		ret = -ENOMEM;
		dev_err(dev, "Failed to allocate IRQs");
		goto fail_map_bars;
	}

	// Set up interrupts
	for (k = 0; k < mqnic->irq_count; k++) {
		ret = pci_request_irq(pdev, k, mqnic_interrupt, NULL,
		                      mqnic, "%s-%d", mqnic->name, k);
		if (ret < 0) {
			dev_err(dev, "Failed to request IRQ");
			goto fail_irq;
		}

		mqnic->irq_map[k] = pci_irq_vector(pdev, k);
	}

	// Board-specific init
	ret = mqnic_board_init(mqnic);
	if (ret) {
		dev_err(dev, "Failed to initialize board");
		goto fail_board;
	}

	// Enable bus mastering for DMA
	pci_set_master(pdev);

	// register PHC
	if (mqnic->phc_count)
		mqnic_register_phc(mqnic);

	// Set up interfaces
	if (mqnic->if_count > MQNIC_MAX_IF)
		mqnic->if_count = MQNIC_MAX_IF;

	for (k = 0; k < mqnic->if_count; k++) {
		dev_info(dev, "Creating interface %d", k);
		ret = mqnic_init_netdev(mqnic, k, mqnic->hw_addr + k * mqnic->if_stride);
		if (ret) {
			dev_err(dev, "Failed to create net_device");
			goto fail_init_netdev;
		}
	}

	// pass module I2C clients to net_device instances
	for (k = 0; k < mqnic->if_count; k++) {
		struct mqnic_priv *priv = netdev_priv(mqnic->ndev[k]);
		priv->mod_i2c_client = mqnic->mod_i2c_client[k];
	}

	mqnic->misc_dev.minor = MISC_DYNAMIC_MINOR;
	mqnic->misc_dev.name = mqnic->name;
	mqnic->misc_dev.fops = &mqnic_fops;
	mqnic->misc_dev.parent = dev;

	ret = misc_register(&mqnic->misc_dev);
	if (ret) {
		dev_err(dev, "misc_register failed: %d\n", ret);
		goto fail_miscdev;
	}

	dev_info(dev, "Registered device %s", mqnic->name);

	pci_save_state(pdev);

	mutex_init(&mqnic->state_lock);

	// probe complete
	return 0;

	// error handling
fail_miscdev:
fail_init_netdev:
	for (k = 0; k < ARRAY_SIZE(mqnic->ndev); k++)
		if (mqnic->ndev[k])
			mqnic_destroy_netdev(mqnic->ndev[k]);
	mqnic_unregister_phc(mqnic);
	pci_clear_master(pdev);
fail_board:
	mqnic_board_deinit(mqnic);
	for (k = 0; k < mqnic->irq_count; k++)
		pci_free_irq(pdev, k, mqnic);
fail_irq:
	pci_free_irq_vectors(pdev);
fail_map_bars:
	if (mqnic->hw_addr)
		pci_iounmap(pdev, mqnic->hw_addr);
	if (mqnic->app_hw_addr)
		pci_iounmap(pdev, mqnic->app_hw_addr);
	if (mqnic->ram_hw_addr)
		pci_iounmap(pdev, mqnic->ram_hw_addr);
	pci_release_regions(pdev);
fail_regions:
	pci_disable_device(pdev);
fail_enable_device:
	spin_lock(&mqnic_devices_lock);
	list_del(&mqnic->dev_list_node);
	spin_unlock(&mqnic_devices_lock);
	return ret;
}

static void mqnic_pci_remove(struct pci_dev *pdev)
{
	struct mqnic_dev *mqnic = pci_get_drvdata(pdev);

	int k = 0;

	dev_info(&pdev->dev, DRIVER_NAME " PCI remove");

	misc_deregister(&mqnic->misc_dev);

	spin_lock(&mqnic_devices_lock);
	list_del(&mqnic->dev_list_node);
	spin_unlock(&mqnic_devices_lock);

	for (k = 0; k < ARRAY_SIZE(mqnic->ndev); k++)
		if (mqnic->ndev[k])
			mqnic_destroy_netdev(mqnic->ndev[k]);

	mqnic_unregister_phc(mqnic);

	pci_clear_master(pdev);
	mqnic_board_deinit(mqnic);
	for (k = 0; k < mqnic->irq_count; k++)
		pci_free_irq(pdev, k, mqnic);
	pci_free_irq_vectors(pdev);
	if (mqnic->hw_addr)
		pci_iounmap(pdev, mqnic->hw_addr);
	if (mqnic->app_hw_addr)
		pci_iounmap(pdev, mqnic->app_hw_addr);
	if (mqnic->ram_hw_addr)
		pci_iounmap(pdev, mqnic->ram_hw_addr);
	pci_release_regions(pdev);
	pci_disable_device(pdev);
}

static void mqnic_pci_shutdown(struct pci_dev *pdev)
{
	dev_info(&pdev->dev, DRIVER_NAME " PCI shutdown");

	mqnic_pci_remove(pdev);
}

static struct pci_driver mqnic_pci_driver = {
	.name = DRIVER_NAME,
	.id_table = mqnic_pci_id_table,
	.probe = mqnic_pci_probe,
	.remove = mqnic_pci_remove,
	.shutdown = mqnic_pci_shutdown
};

static int __init mqnic_init(void)
{
	return pci_register_driver(&mqnic_pci_driver);
}

static void __exit mqnic_exit(void)
{
	pci_unregister_driver(&mqnic_pci_driver);
}

module_init(mqnic_init);
module_exit(mqnic_exit);