text: // SPDX-License-Identifier: GPL-2.0
  /*
   * From setup-res.c, by:
   *	Dave Rusling (david.rusling@reo.mts.dec.com)
   *	David Mosberger (davidm@cs.arizona.edu)
   *	David Miller (davem@redhat.com)
   *	Ivan Kokshaysky (ink@jurassic.park.msu.ru)
   */
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/pci.h>
  #include <linux/errno.h>
  #include <linux/ioport.h>
  #include <linux/proc_fs.h>
  #include <linux/slab.h>
  
  #include "pci.h"
  
  void pci_add_resource_offset(struct list_head *resources, struct resource *res,
  			     resource_size_t offset)
  {
  	struct resource_entry *entry;
  
  	entry = resource_list_create_entry(res, 0);
  	if (!entry) {
  		printk(KERN_ERR "PCI: can't add host bridge window %pR\n", res);
  		return;
  	}
  
  	entry->offset = offset;
  	resource_list_add_tail(entry, resources);
  }
  EXPORT_SYMBOL(pci_add_resource_offset);
  
  void pci_add_resource(struct list_head *resources, struct resource *res)
  {
  	pci_add_resource_offset(resources, res, 0);
  }
  EXPORT_SYMBOL(pci_add_resource);
  
  void pci_free_resource_list(struct list_head *resources)
  {
  	resource_list_free(resources);
  }
  EXPORT_SYMBOL(pci_free_resource_list);
  
  void pci_bus_add_resource(struct pci_bus *bus, struct resource *res,
  			  unsigned int flags)
  {
  	struct pci_bus_resource *bus_res;
  
  	bus_res = kzalloc(sizeof(struct pci_bus_resource), GFP_KERNEL);
  	if (!bus_res) {
  		dev_err(&bus->dev, "can't add %pR resource\n", res);
  		return;
  	}
  
  	bus_res->res = res;
  	bus_res->flags = flags;
  	list_add_tail(&bus_res->list, &bus->resources);
  }
  
  struct resource *pci_bus_resource_n(const struct pci_bus *bus, int n)
  {
  	struct pci_bus_resource *bus_res;
  
  	if (n < PCI_BRIDGE_RESOURCE_NUM)
  		return bus->resource[n];
  
  	n -= PCI_BRIDGE_RESOURCE_NUM;
  	list_for_each_entry(bus_res, &bus->resources, list) {
  		if (n-- == 0)
  			return bus_res->res;
  	}
  	return NULL;
  }
  EXPORT_SYMBOL_GPL(pci_bus_resource_n);
  
  void pci_bus_remove_resources(struct pci_bus *bus)
  {
  	int i;
  	struct pci_bus_resource *bus_res, *tmp;
  
  	for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++)
  		bus->resource[i] = NULL;
  
  	list_for_each_entry_safe(bus_res, tmp, &bus->resources, list) {
  		list_del(&bus_res->list);
  		kfree(bus_res);
  	}
  }
  
  int devm_request_pci_bus_resources(struct device *dev,
  				   struct list_head *resources)
  {
  	struct resource_entry *win;
  	struct resource *parent, *res;
  	int err;
  
  	resource_list_for_each_entry(win, resources) {
  		res = win->res;
  		switch (resource_type(res)) {
  		case IORESOURCE_IO:
  			parent = &ioport_resource;
  			break;
  		case IORESOURCE_MEM:
  			parent = &iomem_resource;
  			break;
  		default:
  			continue;
  		}
  
  		err = devm_request_resource(dev, parent, res);
  		if (err)
  			return err;
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(devm_request_pci_bus_resources);
  
  static struct pci_bus_region pci_32_bit = {0, 0xffffffffULL};
  #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
  static struct pci_bus_region pci_64_bit = {0,
  				(pci_bus_addr_t) 0xffffffffffffffffULL};
  static struct pci_bus_region pci_high = {(pci_bus_addr_t) 0x100000000ULL,
  				(pci_bus_addr_t) 0xffffffffffffffffULL};
  #endif
  
  /*
   * @res contains CPU addresses.  Clip it so the corresponding bus addresses
   * on @bus are entirely within @region.  This is used to control the bus
   * addresses of resources we allocate, e.g., we may need a resource that
   * can be mapped by a 32-bit BAR.
   */
  static void pci_clip_resource_to_region(struct pci_bus *bus,
  					struct resource *res,
  					struct pci_bus_region *region)
  {
  	struct pci_bus_region r;
  
  	pcibios_resource_to_bus(bus, &r, res);
  	if (r.start < region->start)
  		r.start = region->start;
  	if (r.end > region->end)
  		r.end = region->end;
  
  	if (r.end < r.start)
  		res->end = res->start - 1;
  	else
  		pcibios_bus_to_resource(bus, res, &r);
  }
  
  static int pci_bus_alloc_from_region(struct pci_bus *bus, struct resource *res,
  		resource_size_t size, resource_size_t align,
  		resource_size_t min, unsigned long type_mask,
  		resource_size_t (*alignf)(void *,
  					  const struct resource *,
  					  resource_size_t,
  					  resource_size_t),
  		void *alignf_data,
  		struct pci_bus_region *region)
  {
  	int i, ret;
  	struct resource *r, avail;
  	resource_size_t max;
  
  	type_mask |= IORESOURCE_TYPE_BITS;
  
  	pci_bus_for_each_resource(bus, r, i) {
  		resource_size_t min_used = min;
  
  		if (!r)
  			continue;
  
  		/* type_mask must match */
  		if ((res->flags ^ r->flags) & type_mask)
  			continue;
  
  		/* We cannot allocate a non-prefetching resource
  		   from a pre-fetching area */
  		if ((r->flags & IORESOURCE_PREFETCH) &&
  		    !(res->flags & IORESOURCE_PREFETCH))
  			continue;
  
  		avail = *r;
  		pci_clip_resource_to_region(bus, &avail, region);
  
  		/*
  		 * "min" is typically PCIBIOS_MIN_IO or PCIBIOS_MIN_MEM to
  		 * protect badly documented motherboard resources, but if
  		 * this is an already-configured bridge window, its start
  		 * overrides "min".
  		 */
  		if (avail.start)
  			min_used = avail.start;
  
  		max = avail.end;
  
  		/* Ok, try it out.. */
  		ret = allocate_resource(r, res, size, min_used, max,
  					align, alignf, alignf_data);
  		if (ret == 0)
  			return 0;
  	}
  	return -ENOMEM;
  }
  
  /**
   * pci_bus_alloc_resource - allocate a resource from a parent bus
   * @bus: PCI bus
   * @res: resource to allocate
   * @size: size of resource to allocate
   * @align: alignment of resource to allocate
   * @min: minimum /proc/iomem address to allocate
   * @type_mask: IORESOURCE_* type flags
   * @alignf: resource alignment function
   * @alignf_data: data argument for resource alignment function
   *
   * Given the PCI bus a device resides on, the size, minimum address,
   * alignment and type, try to find an acceptable resource allocation
   * for a specific device resource.
   */
  int pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
  		resource_size_t size, resource_size_t align,
  		resource_size_t min, unsigned long type_mask,
  		resource_size_t (*alignf)(void *,
  					  const struct resource *,
  					  resource_size_t,
  					  resource_size_t),
  		void *alignf_data)
  {
  #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
  	int rc;
  
  	if (res->flags & IORESOURCE_MEM_64) {
  		rc = pci_bus_alloc_from_region(bus, res, size, align, min,
  					       type_mask, alignf, alignf_data,
  					       &pci_high);
  		if (rc == 0)
  			return 0;
  
  		return pci_bus_alloc_from_region(bus, res, size, align, min,
  						 type_mask, alignf, alignf_data,
  						 &pci_64_bit);
  	}
  #endif
  
  	return pci_bus_alloc_from_region(bus, res, size, align, min,
  					 type_mask, alignf, alignf_data,
  					 &pci_32_bit);
  }
  EXPORT_SYMBOL(pci_bus_alloc_resource);
  
  /*
   * The @idx resource of @dev should be a PCI-PCI bridge window.  If this
   * resource fits inside a window of an upstream bridge, do nothing.  If it
   * overlaps an upstream window but extends outside it, clip the resource so
   * it fits completely inside.
   */
  bool pci_bus_clip_resource(struct pci_dev *dev, int idx)
  {
  	struct pci_bus *bus = dev->bus;
  	struct resource *res = &dev->resource[idx];
  	struct resource orig_res = *res;
  	struct resource *r;
  	int i;
  
  	pci_bus_for_each_resource(bus, r, i) {
  		resource_size_t start, end;
  
  		if (!r)
  			continue;
  
  		if (resource_type(res) != resource_type(r))
  			continue;
  
  		start = max(r->start, res->start);
  		end = min(r->end, res->end);
  
  		if (start > end)
  			continue;	/* no overlap */
  
  		if (res->start == start && res->end == end)
  			return false;	/* no change */
  
  		res->start = start;
  		res->end = end;
  		res->flags &= ~IORESOURCE_UNSET;
  		orig_res.flags &= ~IORESOURCE_UNSET;
  		pci_printk(KERN_DEBUG, dev, "%pR clipped to %pR\n",
  				 &orig_res, res);
  
  		return true;
  	}
  
  	return false;
  }
  
  void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }
  
  void __weak pcibios_bus_add_device(struct pci_dev *pdev) { }
  
  /**
   * pci_bus_add_device - start driver for a single device
   * @dev: device to add
   *
   * This adds add sysfs entries and start device drivers
   */
  void pci_bus_add_device(struct pci_dev *dev)
  {
  	int retval;
  
  	/*
  	 * Can not put in pci_device_add yet because resources
  	 * are not assigned yet for some devices.
  	 */
  	pcibios_bus_add_device(dev);
  	pci_fixup_device(pci_fixup_final, dev);
  	pci_create_sysfs_dev_files(dev);
  	pci_proc_attach_device(dev);
  	pci_bridge_d3_update(dev);
  
  	dev->match_driver = true;
  	retval = device_attach(&dev->dev);
  	if (retval < 0 && retval != -EPROBE_DEFER) {
  		pci_warn(dev, "device attach failed (%d)\n", retval);
  		pci_proc_detach_device(dev);
  		pci_remove_sysfs_dev_files(dev);
  		return;
  	}
  
  	dev->is_added = 1;
  }
  EXPORT_SYMBOL_GPL(pci_bus_add_device);
  
  /**
   * pci_bus_add_devices - start driver for PCI devices
   * @bus: bus to check for new devices
   *
   * Start driver for PCI devices and add some sysfs entries.
   */
  void pci_bus_add_devices(const struct pci_bus *bus)
  {
  	struct pci_dev *dev;
  	struct pci_bus *child;
  
  	list_for_each_entry(dev, &bus->devices, bus_list) {
  		/* Skip already-added devices */
  		if (dev->is_added)
  			continue;
  		pci_bus_add_device(dev);
  	}
  
  	list_for_each_entry(dev, &bus->devices, bus_list) {
  		/* Skip if device attach failed */
  		if (!dev->is_added)
  			continue;
  		child = dev->subordinate;
  		if (child)
  			pci_bus_add_devices(child);
  	}
  }
  EXPORT_SYMBOL(pci_bus_add_devices);
  
  /** pci_walk_bus - walk devices on/under bus, calling callback.
   *  @top      bus whose devices should be walked
   *  @cb       callback to be called for each device found
   *  @userdata arbitrary pointer to be passed to callback.
   *
   *  Walk the given bus, including any bridged devices
   *  on buses under this bus.  Call the provided callback
   *  on each device found.
   *
   *  We check the return of @cb each time. If it returns anything
   *  other than 0, we break out.
   *
   */
  void pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *),
  		  void *userdata)
  {
  	struct pci_dev *dev;
  	struct pci_bus *bus;
  	struct list_head *next;
  	int retval;
  
  	bus = top;
  	down_read(&pci_bus_sem);
  	next = top->devices.next;
  	for (;;) {
  		if (next == &bus->devices) {
  			/* end of this bus, go up or finish */
  			if (bus == top)
  				break;
  			next = bus->self->bus_list.next;
  			bus = bus->self->bus;
  			continue;
  		}
  		dev = list_entry(next, struct pci_dev, bus_list);
  		if (dev->subordinate) {
  			/* this is a pci-pci bridge, do its devices next */
  			next = dev->subordinate->devices.next;
  			bus = dev->subordinate;
  		} else
  			next = dev->bus_list.next;
  
  		retval = cb(dev, userdata);
  		if (retval)
  			break;
  	}
  	up_read(&pci_bus_sem);
  }
  EXPORT_SYMBOL_GPL(pci_walk_bus);
  
  struct pci_bus *pci_bus_get(struct pci_bus *bus)
  {
  	if (bus)
  		get_device(&bus->dev);
  	return bus;
  }
  EXPORT_SYMBOL(pci_bus_get);
  
  void pci_bus_put(struct pci_bus *bus)
  {
  	if (bus)
  		put_device(&bus->dev);
  }
  EXPORT_SYMBOL(pci_bus_put);
  