/*
 * AMD Cryptographic Coprocessor (CCP) driver
 *
 * Copyright (C) 2013,2016 Advanced Micro Devices, Inc.
 *
 * Author: Tom Lendacky <thomas.lendacky@amd.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/pci.h>
#include <linux/pci_ids.h>
#include <linux/dma-mapping.h>
#include <linux/kthread.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
#include <linux/ccp.h>

#include "ccp-dev.h"

#define IO_BAR				2
#define IO_OFFSET			0x20000

#define MSIX_VECTORS			2

struct ccp_msix {
	u32 vector;
	char name[16];
};

struct ccp_pci {
	int msix_count;
	struct ccp_msix msix[MSIX_VECTORS];
};

static int ccp_get_msix_irqs(struct ccp_device *ccp)
{
	struct ccp_pci *ccp_pci = ccp->dev_specific;
	struct device *dev = ccp->dev;
	struct pci_dev *pdev = to_pci_dev(dev);
	struct msix_entry msix_entry[MSIX_VECTORS];
	unsigned int name_len = sizeof(ccp_pci->msix[0].name) - 1;
	int v, ret;

	for (v = 0; v < ARRAY_SIZE(msix_entry); v++)
		msix_entry[v].entry = v;

	ret = pci_enable_msix_range(pdev, msix_entry, 1, v);
	if (ret < 0)
		return ret;

	ccp_pci->msix_count = ret;
	for (v = 0; v < ccp_pci->msix_count; v++) {
		/* Set the interrupt names and request the irqs */
		snprintf(ccp_pci->msix[v].name, name_len, "%s-%u",
			 ccp->name, v);
		ccp_pci->msix[v].vector = msix_entry[v].vector;
		ret = request_irq(ccp_pci->msix[v].vector,
				  ccp->vdata->perform->irqhandler,
				  0, ccp_pci->msix[v].name, dev);
		if (ret) {
			dev_notice(dev, "unable to allocate MSI-X IRQ (%d)\n",
				   ret);
			goto e_irq;
		}
	}

	return 0;

e_irq:
	while (v--)
		free_irq(ccp_pci->msix[v].vector, dev);

	pci_disable_msix(pdev);

	ccp_pci->msix_count = 0;

	return ret;
}

static int ccp_get_msi_irq(struct ccp_device *ccp)
{
	struct device *dev = ccp->dev;
	struct pci_dev *pdev = to_pci_dev(dev);
	int ret;

	ret = pci_enable_msi(pdev);
	if (ret)
		return ret;

	ccp->irq = pdev->irq;
	ret = request_irq(ccp->irq, ccp->vdata->perform->irqhandler, 0,
			  ccp->name, dev);
	if (ret) {
		dev_notice(dev, "unable to allocate MSI IRQ (%d)\n", ret);
		goto e_msi;
	}

	return 0;

e_msi:
	pci_disable_msi(pdev);

	return ret;
}

static int ccp_get_irqs(struct ccp_device *ccp)
{
	struct device *dev = ccp->dev;
	int ret;

	ret = ccp_get_msix_irqs(ccp);
	if (!ret)
		return 0;

	/* Couldn't get MSI-X vectors, try MSI */
	dev_notice(dev, "could not enable MSI-X (%d), trying MSI\n", ret);
	ret = ccp_get_msi_irq(ccp);
	if (!ret)
		return 0;

	/* Couldn't get MSI interrupt */
	dev_notice(dev, "could not enable MSI (%d)\n", ret);

	return ret;
}

static void ccp_free_irqs(struct ccp_device *ccp)
{
	struct ccp_pci *ccp_pci = ccp->dev_specific;
	struct device *dev = ccp->dev;
	struct pci_dev *pdev = to_pci_dev(dev);

	if (ccp_pci->msix_count) {
		while (ccp_pci->msix_count--)
			free_irq(ccp_pci->msix[ccp_pci->msix_count].vector,
				 dev);
		pci_disable_msix(pdev);
	} else {
		free_irq(ccp->irq, dev);
		pci_disable_msi(pdev);
	}
}

static int ccp_find_mmio_area(struct ccp_device *ccp)
{
	struct device *dev = ccp->dev;
	struct pci_dev *pdev = to_pci_dev(dev);
	resource_size_t io_len;
	unsigned long io_flags;

	io_flags = pci_resource_flags(pdev, IO_BAR);
	io_len = pci_resource_len(pdev, IO_BAR);
	if ((io_flags & IORESOURCE_MEM) && (io_len >= (IO_OFFSET + 0x800)))
		return IO_BAR;

	return -EIO;
}

static int ccp_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
	struct ccp_device *ccp;
	struct ccp_pci *ccp_pci;
	struct device *dev = &pdev->dev;
	unsigned int bar;
	int ret;

	ret = -ENOMEM;
	ccp = ccp_alloc_struct(dev);
	if (!ccp)
		goto e_err;

	ccp_pci = devm_kzalloc(dev, sizeof(*ccp_pci), GFP_KERNEL);
	if (!ccp_pci)
		goto e_err;

	ccp->dev_specific = ccp_pci;
	ccp->vdata = (struct ccp_vdata *)id->driver_data;
	if (!ccp->vdata || !ccp->vdata->version) {
		ret = -ENODEV;
		dev_err(dev, "missing driver data\n");
		goto e_err;
	}
	ccp->get_irq = ccp_get_irqs;
	ccp->free_irq = ccp_free_irqs;

	ret = pci_request_regions(pdev, "ccp");
	if (ret) {
		dev_err(dev, "pci_request_regions failed (%d)\n", ret);
		goto e_err;
	}

	ret = pci_enable_device(pdev);
	if (ret) {
		dev_err(dev, "pci_enable_device failed (%d)\n", ret);
		goto e_regions;
	}

	pci_set_master(pdev);

	ret = ccp_find_mmio_area(ccp);
	if (ret < 0)
		goto e_device;
	bar = ret;

	ret = -EIO;
	ccp->io_map = pci_iomap(pdev, bar, 0);
	if (!ccp->io_map) {
		dev_err(dev, "pci_iomap failed\n");
		goto e_device;
	}
	ccp->io_regs = ccp->io_map + IO_OFFSET;

	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(48));
	if (ret) {
		ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
		if (ret) {
			dev_err(dev, "dma_set_mask_and_coherent failed (%d)\n",
				ret);
			goto e_iomap;
		}
	}

	dev_set_drvdata(dev, ccp);

	ret = ccp->vdata->perform->init(ccp);
	if (ret)
		goto e_iomap;

	dev_notice(dev, "enabled\n");

	return 0;

e_iomap:
	pci_iounmap(pdev, ccp->io_map);

e_device:
	pci_disable_device(pdev);

e_regions:
	pci_release_regions(pdev);

e_err:
	dev_notice(dev, "initialization failed\n");
	return ret;
}

static void ccp_pci_remove(struct pci_dev *pdev)
{
	struct device *dev = &pdev->dev;
	struct ccp_device *ccp = dev_get_drvdata(dev);

	if (!ccp)
		return;

	ccp->vdata->perform->destroy(ccp);

	pci_iounmap(pdev, ccp->io_map);

	pci_disable_device(pdev);

	pci_release_regions(pdev);

	dev_notice(dev, "disabled\n");
}

#ifdef CONFIG_PM
static int ccp_pci_suspend(struct pci_dev *pdev, pm_message_t state)
{
	struct device *dev = &pdev->dev;
	struct ccp_device *ccp = dev_get_drvdata(dev);
	unsigned long flags;
	unsigned int i;

	spin_lock_irqsave(&ccp->cmd_lock, flags);

	ccp->suspending = 1;

	/* Wake all the queue kthreads to prepare for suspend */
	for (i = 0; i < ccp->cmd_q_count; i++)
		wake_up_process(ccp->cmd_q[i].kthread);

	spin_unlock_irqrestore(&ccp->cmd_lock, flags);

	/* Wait for all queue kthreads to say they're done */
	while (!ccp_queues_suspended(ccp))
		wait_event_interruptible(ccp->suspend_queue,
					 ccp_queues_suspended(ccp));

	return 0;
}

static int ccp_pci_resume(struct pci_dev *pdev)
{
	struct device *dev = &pdev->dev;
	struct ccp_device *ccp = dev_get_drvdata(dev);
	unsigned long flags;
	unsigned int i;

	spin_lock_irqsave(&ccp->cmd_lock, flags);

	ccp->suspending = 0;

	/* Wake up all the kthreads */
	for (i = 0; i < ccp->cmd_q_count; i++) {
		ccp->cmd_q[i].suspended = 0;
		wake_up_process(ccp->cmd_q[i].kthread);
	}

	spin_unlock_irqrestore(&ccp->cmd_lock, flags);

	return 0;
}
#endif

static const struct pci_device_id ccp_pci_table[] = {
	{ PCI_VDEVICE(AMD, 0x1537), (kernel_ulong_t)&ccpv3 },
	/* Last entry must be zero */
	{ 0, }
};
MODULE_DEVICE_TABLE(pci, ccp_pci_table);

static struct pci_driver ccp_pci_driver = {
	.name = "ccp",
	.id_table = ccp_pci_table,
	.probe = ccp_pci_probe,
	.remove = ccp_pci_remove,
#ifdef CONFIG_PM
	.suspend = ccp_pci_suspend,
	.resume = ccp_pci_resume,
#endif
};

int ccp_pci_init(void)
{
	return pci_register_driver(&ccp_pci_driver);
}

void ccp_pci_exit(void)
{
	pci_unregister_driver(&ccp_pci_driver);
}