// SPDX-License-Identifier: GPL-2.0+
  /*
   * Copyright (C) 2017 HiSilicon Limited, All Rights Reserved.
   * Author: Gabriele Paoloni <gabriele.paoloni@huawei.com>
   * Author: Zhichang Yuan <yuanzhichang@hisilicon.com>
   */
  
  #define pr_fmt(fmt)	"LOGIC PIO: " fmt
  
  #include <linux/of.h>
  #include <linux/io.h>
  #include <linux/logic_pio.h>
  #include <linux/mm.h>
  #include <linux/rculist.h>
  #include <linux/sizes.h>
  #include <linux/slab.h>
  
  /* The unique hardware address list */
  static LIST_HEAD(io_range_list);
  static DEFINE_MUTEX(io_range_mutex);
  
  /* Consider a kernel general helper for this */
  #define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
  
  /**
   * logic_pio_register_range - register logical PIO range for a host
   * @new_range: pointer to the IO range to be registered.
   *
   * Returns 0 on success, the error code in case of failure.
   *
   * Register a new IO range node in the IO range list.
   */
  int logic_pio_register_range(struct logic_pio_hwaddr *new_range)
  {
  	struct logic_pio_hwaddr *range;
  	resource_size_t start;
  	resource_size_t end;

  	resource_size_t mmio_end = 0;

  	resource_size_t iio_sz = MMIO_UPPER_LIMIT;
  	int ret = 0;
  
  	if (!new_range || !new_range->fwnode || !new_range->size)
  		return -EINVAL;
  
  	start = new_range->hw_start;
  	end = new_range->hw_start + new_range->size;
  
  	mutex_lock(&io_range_mutex);

  	list_for_each_entry(range, &io_range_list, list) {

  		if (range->fwnode == new_range->fwnode) {
  			/* range already there */
  			goto end_register;
  		}
  		if (range->flags == LOGIC_PIO_CPU_MMIO &&
  		    new_range->flags == LOGIC_PIO_CPU_MMIO) {
  			/* for MMIO ranges we need to check for overlap */
  			if (start >= range->hw_start + range->size ||
  			    end < range->hw_start) {

  				mmio_end = range->io_start + range->size;

  			} else {
  				ret = -EFAULT;
  				goto end_register;
  			}
  		} else if (range->flags == LOGIC_PIO_INDIRECT &&
  			   new_range->flags == LOGIC_PIO_INDIRECT) {
  			iio_sz += range->size;
  		}
  	}
  
  	/* range not registered yet, check for available space */
  	if (new_range->flags == LOGIC_PIO_CPU_MMIO) {

  		if (mmio_end + new_range->size - 1 > MMIO_UPPER_LIMIT) {

  			/* if it's too big check if 64K space can be reserved */

  			if (mmio_end + SZ_64K - 1 > MMIO_UPPER_LIMIT) {

  				ret = -E2BIG;
  				goto end_register;
  			}
  			new_range->size = SZ_64K;
  			pr_warn("Requested IO range too big, new size set to 64K
  ");
  		}

  		new_range->io_start = mmio_end;

  	} else if (new_range->flags == LOGIC_PIO_INDIRECT) {
  		if (iio_sz + new_range->size - 1 > IO_SPACE_LIMIT) {
  			ret = -E2BIG;
  			goto end_register;
  		}
  		new_range->io_start = iio_sz;
  	} else {
  		/* invalid flag */
  		ret = -EINVAL;
  		goto end_register;
  	}
  
  	list_add_tail_rcu(&new_range->list, &io_range_list);
  
  end_register:
  	mutex_unlock(&io_range_mutex);
  	return ret;
  }
  
  /**

   * logic_pio_unregister_range - unregister a logical PIO range for a host
   * @range: pointer to the IO range which has been already registered.
   *
   * Unregister a previously-registered IO range node.
   */
  void logic_pio_unregister_range(struct logic_pio_hwaddr *range)
  {
  	mutex_lock(&io_range_mutex);
  	list_del_rcu(&range->list);
  	mutex_unlock(&io_range_mutex);
  	synchronize_rcu();
  }
  
  /**

   * find_io_range_by_fwnode - find logical PIO range for given FW node
   * @fwnode: FW node handle associated with logical PIO range
   *
   * Returns pointer to node on success, NULL otherwise.
   *
   * Traverse the io_range_list to find the registered node for @fwnode.
   */
  struct logic_pio_hwaddr *find_io_range_by_fwnode(struct fwnode_handle *fwnode)
  {

  	struct logic_pio_hwaddr *range, *found_range = NULL;

  	rcu_read_lock();

  	list_for_each_entry_rcu(range, &io_range_list, list) {

  		if (range->fwnode == fwnode) {
  			found_range = range;
  			break;
  		}

  	}

  	rcu_read_unlock();
  
  	return found_range;

  }
  
  /* Return a registered range given an input PIO token */
  static struct logic_pio_hwaddr *find_io_range(unsigned long pio)
  {

  	struct logic_pio_hwaddr *range, *found_range = NULL;

  	rcu_read_lock();

  	list_for_each_entry_rcu(range, &io_range_list, list) {

  		if (in_range(pio, range->io_start, range->size)) {
  			found_range = range;
  			break;
  		}

  	}

  	rcu_read_unlock();
  
  	if (!found_range)
  		pr_err("PIO entry token 0x%lx invalid
  ", pio);
  
  	return found_range;

  }
  
  /**
   * logic_pio_to_hwaddr - translate logical PIO to HW address
   * @pio: logical PIO value
   *
   * Returns HW address if valid, ~0 otherwise.
   *
   * Translate the input logical PIO to the corresponding hardware address.
   * The input PIO should be unique in the whole logical PIO space.
   */
  resource_size_t logic_pio_to_hwaddr(unsigned long pio)
  {
  	struct logic_pio_hwaddr *range;
  
  	range = find_io_range(pio);
  	if (range)
  		return range->hw_start + pio - range->io_start;
  
  	return (resource_size_t)~0;
  }
  
  /**
   * logic_pio_trans_hwaddr - translate HW address to logical PIO
   * @fwnode: FW node reference for the host
   * @addr: Host-relative HW address
   * @size: size to translate
   *
   * Returns Logical PIO value if successful, ~0UL otherwise
   */
  unsigned long logic_pio_trans_hwaddr(struct fwnode_handle *fwnode,
  				     resource_size_t addr, resource_size_t size)
  {
  	struct logic_pio_hwaddr *range;
  
  	range = find_io_range_by_fwnode(fwnode);
  	if (!range || range->flags == LOGIC_PIO_CPU_MMIO) {
  		pr_err("IO range not found or invalid
  ");
  		return ~0UL;
  	}
  	if (range->size < size) {
  		pr_err("resource size %pa cannot fit in IO range size %pa
  ",
  		       &size, &range->size);
  		return ~0UL;
  	}
  	return addr - range->hw_start + range->io_start;
  }
  
  unsigned long logic_pio_trans_cpuaddr(resource_size_t addr)
  {
  	struct logic_pio_hwaddr *range;

  	rcu_read_lock();

  	list_for_each_entry_rcu(range, &io_range_list, list) {
  		if (range->flags != LOGIC_PIO_CPU_MMIO)
  			continue;

  		if (in_range(addr, range->hw_start, range->size)) {
  			unsigned long cpuaddr;
  
  			cpuaddr = addr - range->hw_start + range->io_start;
  
  			rcu_read_unlock();
  			return cpuaddr;
  		}

  	}

  	rcu_read_unlock();
  
  	pr_err("addr %pa not registered in io_range_list
  ", &addr);

  	return ~0UL;
  }
  
  #if defined(CONFIG_INDIRECT_PIO) && defined(PCI_IOBASE)
  #define BUILD_LOGIC_IO(bw, type)					\
  type logic_in##bw(unsigned long addr)					\
  {									\
  	type ret = (type)~0;						\
  									\
  	if (addr < MMIO_UPPER_LIMIT) {					\
  		ret = read##bw(PCI_IOBASE + addr);			\
  	} else if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) { \
  		struct logic_pio_hwaddr *entry = find_io_range(addr);	\
  									\
  		if (entry && entry->ops)				\
  			ret = entry->ops->in(entry->hostdata,		\
  					addr, sizeof(type));		\
  		else							\
  			WARN_ON_ONCE(1);				\
  	}								\
  	return ret;							\
  }									\
  									\
  void logic_out##bw(type value, unsigned long addr)			\
  {									\
  	if (addr < MMIO_UPPER_LIMIT) {					\
  		write##bw(value, PCI_IOBASE + addr);			\
  	} else if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) {	\
  		struct logic_pio_hwaddr *entry = find_io_range(addr);	\
  									\
  		if (entry && entry->ops)				\
  			entry->ops->out(entry->hostdata,		\
  					addr, value, sizeof(type));	\
  		else							\
  			WARN_ON_ONCE(1);				\
  	}								\
  }									\
  									\
  void logic_ins##bw(unsigned long addr, void *buffer,		\
  		   unsigned int count)					\
  {									\
  	if (addr < MMIO_UPPER_LIMIT) {					\
  		reads##bw(PCI_IOBASE + addr, buffer, count);		\
  	} else if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) {	\
  		struct logic_pio_hwaddr *entry = find_io_range(addr);	\
  									\
  		if (entry && entry->ops)				\
  			entry->ops->ins(entry->hostdata,		\
  				addr, buffer, sizeof(type), count);	\
  		else							\
  			WARN_ON_ONCE(1);				\
  	}								\
  									\
  }									\
  									\
  void logic_outs##bw(unsigned long addr, const void *buffer,		\
  		    unsigned int count)					\
  {									\
  	if (addr < MMIO_UPPER_LIMIT) {					\
  		writes##bw(PCI_IOBASE + addr, buffer, count);		\
  	} else if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) {	\
  		struct logic_pio_hwaddr *entry = find_io_range(addr);	\
  									\
  		if (entry && entry->ops)				\
  			entry->ops->outs(entry->hostdata,		\
  				addr, buffer, sizeof(type), count);	\
  		else							\
  			WARN_ON_ONCE(1);				\
  	}								\
  }
  
  BUILD_LOGIC_IO(b, u8)
  EXPORT_SYMBOL(logic_inb);
  EXPORT_SYMBOL(logic_insb);
  EXPORT_SYMBOL(logic_outb);
  EXPORT_SYMBOL(logic_outsb);
  
  BUILD_LOGIC_IO(w, u16)
  EXPORT_SYMBOL(logic_inw);
  EXPORT_SYMBOL(logic_insw);
  EXPORT_SYMBOL(logic_outw);
  EXPORT_SYMBOL(logic_outsw);
  
  BUILD_LOGIC_IO(l, u32)
  EXPORT_SYMBOL(logic_inl);
  EXPORT_SYMBOL(logic_insl);
  EXPORT_SYMBOL(logic_outl);
  EXPORT_SYMBOL(logic_outsl);
  
  #endif /* CONFIG_INDIRECT_PIO && PCI_IOBASE */