/*
   * Volume Management Device driver
   * Copyright (c) 2015, Intel Corporation.
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
   *
   * This program is distributed in the hope it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
   * more details.
   */
  
  #include <linux/device.h>
  #include <linux/interrupt.h>
  #include <linux/irq.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/msi.h>
  #include <linux/pci.h>

  #include <linux/srcu.h>

  #include <linux/rculist.h>
  #include <linux/rcupdate.h>
  
  #include <asm/irqdomain.h>
  #include <asm/device.h>
  #include <asm/msi.h>
  #include <asm/msidef.h>
  
  #define VMD_CFGBAR	0
  #define VMD_MEMBAR1	2
  #define VMD_MEMBAR2	4
  
  /*
   * Lock for manipulating VMD IRQ lists.
   */
  static DEFINE_RAW_SPINLOCK(list_lock);
  
  /**
   * struct vmd_irq - private data to map driver IRQ to the VMD shared vector
   * @node:	list item for parent traversal.

   * @irq:	back pointer to parent.

   * @enabled:	true if driver enabled IRQ

   * @virq:	the virtual IRQ value provided to the requesting driver.
   *
   * Every MSI/MSI-X IRQ requested for a device in a VMD domain will be mapped to
   * a VMD IRQ using this structure.
   */
  struct vmd_irq {
  	struct list_head	node;

  	struct vmd_irq_list	*irq;

  	bool			enabled;

  	unsigned int		virq;
  };
  
  /**
   * struct vmd_irq_list - list of driver requested IRQs mapping to a VMD vector
   * @irq_list:	the list of irq's the VMD one demuxes to.

   * @srcu:	SRCU struct for local synchronization.

   * @count:	number of child IRQs assigned to this vector; used to track
   *		sharing.
   */
  struct vmd_irq_list {
  	struct list_head	irq_list;

  	struct srcu_struct	srcu;

  	unsigned int		count;
  };
  
  struct vmd_dev {
  	struct pci_dev		*dev;
  
  	spinlock_t		cfg_lock;
  	char __iomem		*cfgbar;
  
  	int msix_count;

  	struct vmd_irq_list	*irqs;
  
  	struct pci_sysdata	sysdata;
  	struct resource		resources[3];
  	struct irq_domain	*irq_domain;
  	struct pci_bus		*bus;
  
  #ifdef CONFIG_X86_DEV_DMA_OPS
  	struct dma_map_ops	dma_ops;
  	struct dma_domain	dma_domain;
  #endif
  };
  
  static inline struct vmd_dev *vmd_from_bus(struct pci_bus *bus)
  {
  	return container_of(bus->sysdata, struct vmd_dev, sysdata);
  }

  static inline unsigned int index_from_irqs(struct vmd_dev *vmd,
  					   struct vmd_irq_list *irqs)
  {
  	return irqs - vmd->irqs;
  }

  /*
   * Drivers managing a device in a VMD domain allocate their own IRQs as before,
   * but the MSI entry for the hardware it's driving will be programmed with a
   * destination ID for the VMD MSI-X table.  The VMD muxes interrupts in its
   * domain into one of its own, and the VMD driver de-muxes these for the
   * handlers sharing that VMD IRQ.  The vmd irq_domain provides the operations
   * and irq_chip to set this up.
   */
  static void vmd_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
  {
  	struct vmd_irq *vmdirq = data->chip_data;
  	struct vmd_irq_list *irq = vmdirq->irq;

  	struct vmd_dev *vmd = irq_data_get_irq_handler_data(data);

  
  	msg->address_hi = MSI_ADDR_BASE_HI;

  	msg->address_lo = MSI_ADDR_BASE_LO |
  			  MSI_ADDR_DEST_ID(index_from_irqs(vmd, irq));

  	msg->data = 0;
  }
  
  /*
   * We rely on MSI_FLAG_USE_DEF_CHIP_OPS to set the IRQ mask/unmask ops.
   */
  static void vmd_irq_enable(struct irq_data *data)
  {
  	struct vmd_irq *vmdirq = data->chip_data;

  	unsigned long flags;

  	raw_spin_lock_irqsave(&list_lock, flags);

  	WARN_ON(vmdirq->enabled);

  	list_add_tail_rcu(&vmdirq->node, &vmdirq->irq->irq_list);

  	vmdirq->enabled = true;

  	raw_spin_unlock_irqrestore(&list_lock, flags);

  
  	data->chip->irq_unmask(data);
  }
  
  static void vmd_irq_disable(struct irq_data *data)
  {
  	struct vmd_irq *vmdirq = data->chip_data;

  	unsigned long flags;

  
  	data->chip->irq_mask(data);

  	raw_spin_lock_irqsave(&list_lock, flags);

  	if (vmdirq->enabled) {
  		list_del_rcu(&vmdirq->node);
  		vmdirq->enabled = false;
  	}

  	raw_spin_unlock_irqrestore(&list_lock, flags);

  }
  
  /*
   * XXX: Stubbed until we develop acceptable way to not create conflicts with
   * other devices sharing the same vector.
   */
  static int vmd_irq_set_affinity(struct irq_data *data,
  				const struct cpumask *dest, bool force)
  {
  	return -EINVAL;
  }
  
  static struct irq_chip vmd_msi_controller = {
  	.name			= "VMD-MSI",
  	.irq_enable		= vmd_irq_enable,
  	.irq_disable		= vmd_irq_disable,
  	.irq_compose_msi_msg	= vmd_compose_msi_msg,
  	.irq_set_affinity	= vmd_irq_set_affinity,
  };
  
  static irq_hw_number_t vmd_get_hwirq(struct msi_domain_info *info,
  				     msi_alloc_info_t *arg)
  {
  	return 0;
  }
  
  /*
   * XXX: We can be even smarter selecting the best IRQ once we solve the
   * affinity problem.
   */

  static struct vmd_irq_list *vmd_next_irq(struct vmd_dev *vmd, struct msi_desc *desc)

  {

  	int i, best = 1;

  	unsigned long flags;

  	if (!desc->msi_attrib.is_msix || vmd->msix_count == 1)
  		return &vmd->irqs[0];

  	raw_spin_lock_irqsave(&list_lock, flags);

  	for (i = 1; i < vmd->msix_count; i++)
  		if (vmd->irqs[i].count < vmd->irqs[best].count)
  			best = i;
  	vmd->irqs[best].count++;

  	raw_spin_unlock_irqrestore(&list_lock, flags);

  
  	return &vmd->irqs[best];
  }
  
  static int vmd_msi_init(struct irq_domain *domain, struct msi_domain_info *info,
  			unsigned int virq, irq_hw_number_t hwirq,
  			msi_alloc_info_t *arg)
  {

  	struct msi_desc *desc = arg->desc;
  	struct vmd_dev *vmd = vmd_from_bus(msi_desc_to_pci_dev(desc)->bus);

  	struct vmd_irq *vmdirq = kzalloc(sizeof(*vmdirq), GFP_KERNEL);

  	unsigned int index, vector;

  
  	if (!vmdirq)
  		return -ENOMEM;
  
  	INIT_LIST_HEAD(&vmdirq->node);

  	vmdirq->irq = vmd_next_irq(vmd, desc);

  	vmdirq->virq = virq;

  	index = index_from_irqs(vmd, vmdirq->irq);
  	vector = pci_irq_vector(vmd->dev, index);

  	irq_domain_set_info(domain, virq, vector, info->chip, vmdirq,

  			    handle_untracked_irq, vmd, NULL);

  	return 0;
  }
  
  static void vmd_msi_free(struct irq_domain *domain,
  			struct msi_domain_info *info, unsigned int virq)
  {
  	struct vmd_irq *vmdirq = irq_get_chip_data(virq);

  	unsigned long flags;

  	synchronize_srcu(&vmdirq->irq->srcu);

  	/* XXX: Potential optimization to rebalance */

  	raw_spin_lock_irqsave(&list_lock, flags);

  	vmdirq->irq->count--;

  	raw_spin_unlock_irqrestore(&list_lock, flags);

  	kfree(vmdirq);

  }
  
  static int vmd_msi_prepare(struct irq_domain *domain, struct device *dev,
  			   int nvec, msi_alloc_info_t *arg)
  {
  	struct pci_dev *pdev = to_pci_dev(dev);
  	struct vmd_dev *vmd = vmd_from_bus(pdev->bus);
  
  	if (nvec > vmd->msix_count)
  		return vmd->msix_count;
  
  	memset(arg, 0, sizeof(*arg));
  	return 0;
  }
  
  static void vmd_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
  {
  	arg->desc = desc;
  }
  
  static struct msi_domain_ops vmd_msi_domain_ops = {
  	.get_hwirq	= vmd_get_hwirq,
  	.msi_init	= vmd_msi_init,
  	.msi_free	= vmd_msi_free,
  	.msi_prepare	= vmd_msi_prepare,
  	.set_desc	= vmd_set_desc,
  };
  
  static struct msi_domain_info vmd_msi_domain_info = {
  	.flags		= MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
  			  MSI_FLAG_PCI_MSIX,
  	.ops		= &vmd_msi_domain_ops,
  	.chip		= &vmd_msi_controller,
  };
  
  #ifdef CONFIG_X86_DEV_DMA_OPS
  /*
   * VMD replaces the requester ID with its own.  DMA mappings for devices in a
   * VMD domain need to be mapped for the VMD, not the device requiring
   * the mapping.
   */
  static struct device *to_vmd_dev(struct device *dev)
  {
  	struct pci_dev *pdev = to_pci_dev(dev);
  	struct vmd_dev *vmd = vmd_from_bus(pdev->bus);
  
  	return &vmd->dev->dev;
  }

  static const struct dma_map_ops *vmd_dma_ops(struct device *dev)

  {

  	return get_dma_ops(to_vmd_dev(dev));

  }
  
  static void *vmd_alloc(struct device *dev, size_t size, dma_addr_t *addr,

  		       gfp_t flag, unsigned long attrs)

  {
  	return vmd_dma_ops(dev)->alloc(to_vmd_dev(dev), size, addr, flag,
  				       attrs);
  }
  
  static void vmd_free(struct device *dev, size_t size, void *vaddr,

  		     dma_addr_t addr, unsigned long attrs)

  {
  	return vmd_dma_ops(dev)->free(to_vmd_dev(dev), size, vaddr, addr,
  				      attrs);
  }
  
  static int vmd_mmap(struct device *dev, struct vm_area_struct *vma,
  		    void *cpu_addr, dma_addr_t addr, size_t size,

  		    unsigned long attrs)

  {
  	return vmd_dma_ops(dev)->mmap(to_vmd_dev(dev), vma, cpu_addr, addr,
  				      size, attrs);
  }
  
  static int vmd_get_sgtable(struct device *dev, struct sg_table *sgt,
  			   void *cpu_addr, dma_addr_t addr, size_t size,

  			   unsigned long attrs)

  {
  	return vmd_dma_ops(dev)->get_sgtable(to_vmd_dev(dev), sgt, cpu_addr,
  					     addr, size, attrs);
  }
  
  static dma_addr_t vmd_map_page(struct device *dev, struct page *page,
  			       unsigned long offset, size_t size,
  			       enum dma_data_direction dir,

  			       unsigned long attrs)

  {
  	return vmd_dma_ops(dev)->map_page(to_vmd_dev(dev), page, offset, size,
  					  dir, attrs);
  }
  
  static void vmd_unmap_page(struct device *dev, dma_addr_t addr, size_t size,

  			   enum dma_data_direction dir, unsigned long attrs)

  {
  	vmd_dma_ops(dev)->unmap_page(to_vmd_dev(dev), addr, size, dir, attrs);
  }
  
  static int vmd_map_sg(struct device *dev, struct scatterlist *sg, int nents,

  		      enum dma_data_direction dir, unsigned long attrs)

  {
  	return vmd_dma_ops(dev)->map_sg(to_vmd_dev(dev), sg, nents, dir, attrs);
  }
  
  static void vmd_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,

  			 enum dma_data_direction dir, unsigned long attrs)

  {
  	vmd_dma_ops(dev)->unmap_sg(to_vmd_dev(dev), sg, nents, dir, attrs);
  }
  
  static void vmd_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
  				    size_t size, enum dma_data_direction dir)
  {
  	vmd_dma_ops(dev)->sync_single_for_cpu(to_vmd_dev(dev), addr, size, dir);
  }
  
  static void vmd_sync_single_for_device(struct device *dev, dma_addr_t addr,
  				       size_t size, enum dma_data_direction dir)
  {
  	vmd_dma_ops(dev)->sync_single_for_device(to_vmd_dev(dev), addr, size,
  						 dir);
  }
  
  static void vmd_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
  				int nents, enum dma_data_direction dir)
  {
  	vmd_dma_ops(dev)->sync_sg_for_cpu(to_vmd_dev(dev), sg, nents, dir);
  }
  
  static void vmd_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
  				   int nents, enum dma_data_direction dir)
  {
  	vmd_dma_ops(dev)->sync_sg_for_device(to_vmd_dev(dev), sg, nents, dir);
  }
  
  static int vmd_mapping_error(struct device *dev, dma_addr_t addr)
  {
  	return vmd_dma_ops(dev)->mapping_error(to_vmd_dev(dev), addr);
  }
  
  static int vmd_dma_supported(struct device *dev, u64 mask)
  {
  	return vmd_dma_ops(dev)->dma_supported(to_vmd_dev(dev), mask);
  }
  
  #ifdef ARCH_HAS_DMA_GET_REQUIRED_MASK
  static u64 vmd_get_required_mask(struct device *dev)
  {
  	return vmd_dma_ops(dev)->get_required_mask(to_vmd_dev(dev));
  }
  #endif
  
  static void vmd_teardown_dma_ops(struct vmd_dev *vmd)
  {
  	struct dma_domain *domain = &vmd->dma_domain;

  	if (get_dma_ops(&vmd->dev->dev))

  		del_dma_domain(domain);
  }
  
  #define ASSIGN_VMD_DMA_OPS(source, dest, fn)	\
  	do {					\
  		if (source->fn)			\
  			dest->fn = vmd_##fn;	\
  	} while (0)
  
  static void vmd_setup_dma_ops(struct vmd_dev *vmd)
  {

  	const struct dma_map_ops *source = get_dma_ops(&vmd->dev->dev);

  	struct dma_map_ops *dest = &vmd->dma_ops;
  	struct dma_domain *domain = &vmd->dma_domain;
  
  	domain->domain_nr = vmd->sysdata.domain;
  	domain->dma_ops = dest;
  
  	if (!source)
  		return;
  	ASSIGN_VMD_DMA_OPS(source, dest, alloc);
  	ASSIGN_VMD_DMA_OPS(source, dest, free);
  	ASSIGN_VMD_DMA_OPS(source, dest, mmap);
  	ASSIGN_VMD_DMA_OPS(source, dest, get_sgtable);
  	ASSIGN_VMD_DMA_OPS(source, dest, map_page);
  	ASSIGN_VMD_DMA_OPS(source, dest, unmap_page);
  	ASSIGN_VMD_DMA_OPS(source, dest, map_sg);
  	ASSIGN_VMD_DMA_OPS(source, dest, unmap_sg);
  	ASSIGN_VMD_DMA_OPS(source, dest, sync_single_for_cpu);
  	ASSIGN_VMD_DMA_OPS(source, dest, sync_single_for_device);
  	ASSIGN_VMD_DMA_OPS(source, dest, sync_sg_for_cpu);
  	ASSIGN_VMD_DMA_OPS(source, dest, sync_sg_for_device);
  	ASSIGN_VMD_DMA_OPS(source, dest, mapping_error);
  	ASSIGN_VMD_DMA_OPS(source, dest, dma_supported);
  #ifdef ARCH_HAS_DMA_GET_REQUIRED_MASK
  	ASSIGN_VMD_DMA_OPS(source, dest, get_required_mask);
  #endif
  	add_dma_domain(domain);
  }
  #undef ASSIGN_VMD_DMA_OPS
  #else
  static void vmd_teardown_dma_ops(struct vmd_dev *vmd) {}
  static void vmd_setup_dma_ops(struct vmd_dev *vmd) {}
  #endif
  
  static char __iomem *vmd_cfg_addr(struct vmd_dev *vmd, struct pci_bus *bus,
  				  unsigned int devfn, int reg, int len)
  {
  	char __iomem *addr = vmd->cfgbar +
  			     (bus->number << 20) + (devfn << 12) + reg;
  
  	if ((addr - vmd->cfgbar) + len >=
  	    resource_size(&vmd->dev->resource[VMD_CFGBAR]))
  		return NULL;
  
  	return addr;
  }
  
  /*
   * CPU may deadlock if config space is not serialized on some versions of this
   * hardware, so all config space access is done under a spinlock.
   */
  static int vmd_pci_read(struct pci_bus *bus, unsigned int devfn, int reg,
  			int len, u32 *value)
  {
  	struct vmd_dev *vmd = vmd_from_bus(bus);
  	char __iomem *addr = vmd_cfg_addr(vmd, bus, devfn, reg, len);
  	unsigned long flags;
  	int ret = 0;
  
  	if (!addr)
  		return -EFAULT;
  
  	spin_lock_irqsave(&vmd->cfg_lock, flags);
  	switch (len) {
  	case 1:
  		*value = readb(addr);
  		break;
  	case 2:
  		*value = readw(addr);
  		break;
  	case 4:
  		*value = readl(addr);
  		break;
  	default:
  		ret = -EINVAL;
  		break;
  	}
  	spin_unlock_irqrestore(&vmd->cfg_lock, flags);
  	return ret;
  }
  
  /*
   * VMD h/w converts non-posted config writes to posted memory writes. The
   * read-back in this function forces the completion so it returns only after
   * the config space was written, as expected.
   */
  static int vmd_pci_write(struct pci_bus *bus, unsigned int devfn, int reg,
  			 int len, u32 value)
  {
  	struct vmd_dev *vmd = vmd_from_bus(bus);
  	char __iomem *addr = vmd_cfg_addr(vmd, bus, devfn, reg, len);
  	unsigned long flags;
  	int ret = 0;
  
  	if (!addr)
  		return -EFAULT;
  
  	spin_lock_irqsave(&vmd->cfg_lock, flags);
  	switch (len) {
  	case 1:
  		writeb(value, addr);
  		readb(addr);
  		break;
  	case 2:
  		writew(value, addr);
  		readw(addr);
  		break;
  	case 4:
  		writel(value, addr);
  		readl(addr);
  		break;
  	default:
  		ret = -EINVAL;
  		break;
  	}
  	spin_unlock_irqrestore(&vmd->cfg_lock, flags);
  	return ret;
  }
  
  static struct pci_ops vmd_ops = {
  	.read		= vmd_pci_read,
  	.write		= vmd_pci_write,
  };

  static void vmd_attach_resources(struct vmd_dev *vmd)
  {
  	vmd->dev->resource[VMD_MEMBAR1].child = &vmd->resources[1];
  	vmd->dev->resource[VMD_MEMBAR2].child = &vmd->resources[2];
  }
  
  static void vmd_detach_resources(struct vmd_dev *vmd)
  {
  	vmd->dev->resource[VMD_MEMBAR1].child = NULL;
  	vmd->dev->resource[VMD_MEMBAR2].child = NULL;
  }

  /*
   * VMD domains start at 0x1000 to not clash with ACPI _SEG domains.
   */
  static int vmd_find_free_domain(void)
  {
  	int domain = 0xffff;
  	struct pci_bus *bus = NULL;
  
  	while ((bus = pci_find_next_bus(bus)) != NULL)
  		domain = max_t(int, domain, pci_domain_nr(bus));
  	return domain + 1;
  }
  
  static int vmd_enable_domain(struct vmd_dev *vmd)
  {
  	struct pci_sysdata *sd = &vmd->sysdata;
  	struct resource *res;
  	u32 upper_bits;
  	unsigned long flags;
  	LIST_HEAD(resources);
  
  	res = &vmd->dev->resource[VMD_CFGBAR];
  	vmd->resources[0] = (struct resource) {
  		.name  = "VMD CFGBAR",

  		.start = 0,

  		.end   = (resource_size(res) >> 20) - 1,
  		.flags = IORESOURCE_BUS | IORESOURCE_PCI_FIXED,
  	};

  	/*
  	 * If the window is below 4GB, clear IORESOURCE_MEM_64 so we can
  	 * put 32-bit resources in the window.
  	 *
  	 * There's no hardware reason why a 64-bit window *couldn't*
  	 * contain a 32-bit resource, but pbus_size_mem() computes the
  	 * bridge window size assuming a 64-bit window will contain no
  	 * 32-bit resources.  __pci_assign_resource() enforces that
  	 * artificial restriction to make sure everything will fit.
  	 *
  	 * The only way we could use a 64-bit non-prefechable MEMBAR is
  	 * if its address is <4GB so that we can convert it to a 32-bit
  	 * resource.  To be visible to the host OS, all VMD endpoints must
  	 * be initially configured by platform BIOS, which includes setting
  	 * up these resources.  We can assume the device is configured
  	 * according to the platform needs.
  	 */

  	res = &vmd->dev->resource[VMD_MEMBAR1];
  	upper_bits = upper_32_bits(res->end);
  	flags = res->flags & ~IORESOURCE_SIZEALIGN;
  	if (!upper_bits)
  		flags &= ~IORESOURCE_MEM_64;
  	vmd->resources[1] = (struct resource) {
  		.name  = "VMD MEMBAR1",
  		.start = res->start,
  		.end   = res->end,
  		.flags = flags,

  		.parent = res,

  	};
  
  	res = &vmd->dev->resource[VMD_MEMBAR2];
  	upper_bits = upper_32_bits(res->end);
  	flags = res->flags & ~IORESOURCE_SIZEALIGN;
  	if (!upper_bits)
  		flags &= ~IORESOURCE_MEM_64;
  	vmd->resources[2] = (struct resource) {
  		.name  = "VMD MEMBAR2",
  		.start = res->start + 0x2000,
  		.end   = res->end,
  		.flags = flags,

  		.parent = res,

  	};

  	sd->vmd_domain = true;

  	sd->domain = vmd_find_free_domain();
  	if (sd->domain < 0)
  		return sd->domain;
  
  	sd->node = pcibus_to_node(vmd->dev->bus);
  
  	vmd->irq_domain = pci_msi_create_irq_domain(NULL, &vmd_msi_domain_info,

  						    x86_vector_domain);

  	if (!vmd->irq_domain)
  		return -ENODEV;
  
  	pci_add_resource(&resources, &vmd->resources[0]);
  	pci_add_resource(&resources, &vmd->resources[1]);
  	pci_add_resource(&resources, &vmd->resources[2]);
  	vmd->bus = pci_create_root_bus(&vmd->dev->dev, 0, &vmd_ops, sd,
  				       &resources);
  	if (!vmd->bus) {
  		pci_free_resource_list(&resources);
  		irq_domain_remove(vmd->irq_domain);
  		return -ENODEV;
  	}

  	vmd_attach_resources(vmd);

  	vmd_setup_dma_ops(vmd);
  	dev_set_msi_domain(&vmd->bus->dev, vmd->irq_domain);
  	pci_rescan_bus(vmd->bus);
  
  	WARN(sysfs_create_link(&vmd->dev->dev.kobj, &vmd->bus->dev.kobj,
  			       "domain"), "Can't create symlink to domain
  ");
  	return 0;
  }
  
  static irqreturn_t vmd_irq(int irq, void *data)
  {
  	struct vmd_irq_list *irqs = data;
  	struct vmd_irq *vmdirq;

  	int idx;

  	idx = srcu_read_lock(&irqs->srcu);

  	list_for_each_entry_rcu(vmdirq, &irqs->irq_list, node)
  		generic_handle_irq(vmdirq->virq);

  	srcu_read_unlock(&irqs->srcu, idx);

  
  	return IRQ_HANDLED;
  }
  
  static int vmd_probe(struct pci_dev *dev, const struct pci_device_id *id)
  {
  	struct vmd_dev *vmd;
  	int i, err;
  
  	if (resource_size(&dev->resource[VMD_CFGBAR]) < (1 << 20))
  		return -ENOMEM;
  
  	vmd = devm_kzalloc(&dev->dev, sizeof(*vmd), GFP_KERNEL);
  	if (!vmd)
  		return -ENOMEM;
  
  	vmd->dev = dev;
  	err = pcim_enable_device(dev);
  	if (err < 0)
  		return err;
  
  	vmd->cfgbar = pcim_iomap(dev, VMD_CFGBAR, 0);
  	if (!vmd->cfgbar)
  		return -ENOMEM;
  
  	pci_set_master(dev);
  	if (dma_set_mask_and_coherent(&dev->dev, DMA_BIT_MASK(64)) &&
  	    dma_set_mask_and_coherent(&dev->dev, DMA_BIT_MASK(32)))
  		return -ENODEV;
  
  	vmd->msix_count = pci_msix_vec_count(dev);
  	if (vmd->msix_count < 0)
  		return -ENODEV;

  	vmd->msix_count = pci_alloc_irq_vectors(dev, 1, vmd->msix_count,
  					PCI_IRQ_MSIX | PCI_IRQ_AFFINITY);

  	if (vmd->msix_count < 0)
  		return vmd->msix_count;

  	vmd->irqs = devm_kcalloc(&dev->dev, vmd->msix_count, sizeof(*vmd->irqs),
  				 GFP_KERNEL);
  	if (!vmd->irqs)
  		return -ENOMEM;

  	for (i = 0; i < vmd->msix_count; i++) {

  		err = init_srcu_struct(&vmd->irqs[i].srcu);
  		if (err)
  			return err;

  		INIT_LIST_HEAD(&vmd->irqs[i].irq_list);

  		err = devm_request_irq(&dev->dev, pci_irq_vector(dev, i),

  				       vmd_irq, 0, "vmd", &vmd->irqs[i]);
  		if (err)
  			return err;
  	}
  
  	spin_lock_init(&vmd->cfg_lock);
  	pci_set_drvdata(dev, vmd);
  	err = vmd_enable_domain(vmd);
  	if (err)
  		return err;
  
  	dev_info(&vmd->dev->dev, "Bound to PCI domain %04x
  ",
  		 vmd->sysdata.domain);
  	return 0;
  }

  static void vmd_cleanup_srcu(struct vmd_dev *vmd)
  {
  	int i;
  
  	for (i = 0; i < vmd->msix_count; i++)
  		cleanup_srcu_struct(&vmd->irqs[i].srcu);
  }

  static void vmd_remove(struct pci_dev *dev)
  {
  	struct vmd_dev *vmd = pci_get_drvdata(dev);

  	vmd_detach_resources(vmd);

  	vmd_cleanup_srcu(vmd);

  	sysfs_remove_link(&vmd->dev->dev.kobj, "domain");
  	pci_stop_root_bus(vmd->bus);
  	pci_remove_root_bus(vmd->bus);
  	vmd_teardown_dma_ops(vmd);
  	irq_domain_remove(vmd->irq_domain);
  }

  #ifdef CONFIG_PM_SLEEP

  static int vmd_suspend(struct device *dev)
  {
  	struct pci_dev *pdev = to_pci_dev(dev);
  
  	pci_save_state(pdev);
  	return 0;
  }
  
  static int vmd_resume(struct device *dev)
  {
  	struct pci_dev *pdev = to_pci_dev(dev);
  
  	pci_restore_state(pdev);
  	return 0;
  }
  #endif
  static SIMPLE_DEV_PM_OPS(vmd_dev_pm_ops, vmd_suspend, vmd_resume);
  
  static const struct pci_device_id vmd_ids[] = {
  	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x201d),},
  	{0,}
  };
  MODULE_DEVICE_TABLE(pci, vmd_ids);
  
  static struct pci_driver vmd_drv = {
  	.name		= "vmd",
  	.id_table	= vmd_ids,
  	.probe		= vmd_probe,
  	.remove		= vmd_remove,
  	.driver		= {
  		.pm	= &vmd_dev_pm_ops,
  	},
  };
  module_pci_driver(vmd_drv);
  
  MODULE_AUTHOR("Intel Corporation");
  MODULE_LICENSE("GPL v2");
  MODULE_VERSION("0.6");