/*
   * Intel MIC Platform Software Stack (MPSS)
   *
   * This file is provided under a dual BSD/GPLv2 license.  When using or
   * redistributing this file, you may do so under either license.
   *
   * GPL LICENSE SUMMARY
   *
   * Copyright(c) 2015 Intel Corporation.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of version 2 of the GNU General Public License as
   * published by the Free Software Foundation.
   *
   * This program is distributed in the hope that 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.
   *
   * BSD LICENSE
   *
   * Copyright(c) 2015 Intel Corporation.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * * Redistributions of source code must retain the above copyright
   *   notice, this list of conditions and the following disclaimer.
   * * 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.
   * * Neither the name of Intel Corporation nor the names of its
   *   contributors may be used to endorse or promote products derived
   *   from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "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 COPYRIGHT
   * OWNER 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.
   *
   * Intel SCIF driver.
   *
   */
  #ifndef SCIF_RMA_H
  #define SCIF_RMA_H
  
  #include <linux/dma_remapping.h>
  #include <linux/mmu_notifier.h>
  
  #include "../bus/scif_bus.h"
  
  /* If this bit is set then the mark is a remote fence mark */
  #define SCIF_REMOTE_FENCE_BIT          31
  /* Magic value used to indicate a remote fence request */
  #define SCIF_REMOTE_FENCE BIT_ULL(SCIF_REMOTE_FENCE_BIT)
  
  #define SCIF_MAX_UNALIGNED_BUF_SIZE (1024 * 1024ULL)
  #define SCIF_KMEM_UNALIGNED_BUF_SIZE (SCIF_MAX_UNALIGNED_BUF_SIZE + \
  				      (L1_CACHE_BYTES << 1))
  
  #define SCIF_IOVA_START_PFN		(1)
  #define SCIF_IOVA_PFN(addr) ((addr) >> PAGE_SHIFT)
  #define SCIF_DMA_64BIT_PFN SCIF_IOVA_PFN(DMA_BIT_MASK(64))
  #define SCIF_DMA_63BIT_PFN SCIF_IOVA_PFN(DMA_BIT_MASK(63))
  
  /*
   * struct scif_endpt_rma_info - Per Endpoint Remote Memory Access Information
   *
   * @reg_list: List of registration windows for self
   * @remote_reg_list: List of registration windows for peer
   * @iovad: Offset generator
   * @rma_lock: Synchronizes access to self/remote list and also protects the
   *	      window from being destroyed while RMAs are in progress.
   * @tc_lock: Synchronizes access to temporary cached windows list
   *	     for SCIF Registration Caching.
   * @mmn_lock: Synchronizes access to the list of MMU notifiers registered
   * @tw_refcount: Keeps track of number of outstanding temporary registered
   *		 windows created by scif_vreadfrom/scif_vwriteto which have
   *		 not been destroyed.
   * @tcw_refcount: Same as tw_refcount but for temporary cached windows
   * @tcw_total_pages: Same as tcw_refcount but in terms of pages pinned
   * @mmn_list: MMU notifier so that we can destroy the windows when required
   * @fence_refcount: Keeps track of number of outstanding remote fence
   *		    requests which have been received by the peer.
   * @dma_chan: DMA channel used for all DMA transfers for this endpoint.
   * @async_list_del: Detect asynchronous list entry deletion
   * @vma_list: List of vmas with remote memory mappings
   * @markwq: Wait queue used for scif_fence_mark/scif_fence_wait
  */
  struct scif_endpt_rma_info {
  	struct list_head reg_list;
  	struct list_head remote_reg_list;
  	struct iova_domain iovad;
  	struct mutex rma_lock;
  	spinlock_t tc_lock;
  	struct mutex mmn_lock;
  	atomic_t tw_refcount;
  	atomic_t tcw_refcount;
  	atomic_t tcw_total_pages;
  	struct list_head mmn_list;
  	atomic_t fence_refcount;
  	struct dma_chan	*dma_chan;
  	int async_list_del;
  	struct list_head vma_list;
  	wait_queue_head_t markwq;
  };
  
  /*
   * struct scif_fence_info - used for tracking fence requests
   *
   * @state: State of this transfer
   * @wq: Fences wait on this queue
   * @dma_mark: Used for storing the DMA mark
   */
  struct scif_fence_info {
  	enum scif_msg_state state;
  	struct completion comp;
  	int dma_mark;
  };
  
  /*
   * struct scif_remote_fence_info - used for tracking remote fence requests
   *
   * @msg: List of SCIF node QP fence messages
   * @list: Link to list of remote fence requests
   */
  struct scif_remote_fence_info {
  	struct scifmsg msg;
  	struct list_head list;
  };
  
  /*
   * Specifies whether an RMA operation can span across partial windows, a single
   * window or multiple contiguous windows. Mmaps can span across partial windows.
   * Unregistration can span across complete windows. scif_get_pages() can span a
   * single window. A window can also be of type self or peer.
   */
  enum scif_window_type {
  	SCIF_WINDOW_PARTIAL,
  	SCIF_WINDOW_SINGLE,
  	SCIF_WINDOW_FULL,
  	SCIF_WINDOW_SELF,
  	SCIF_WINDOW_PEER
  };
  
  /* The number of physical addresses that can be stored in a PAGE. */
  #define SCIF_NR_ADDR_IN_PAGE   (0x1000 >> 3)
  
  /*
   * struct scif_rma_lookup - RMA lookup data structure for page list transfers
   *
   * Store an array of lookup offsets. Each offset in this array maps
   * one 4K page containing 512 physical addresses i.e. 2MB. 512 such
   * offsets in a 4K page will correspond to 1GB of registered address space.
  
   * @lookup: Array of offsets
   * @offset: DMA offset of lookup array
   */
  struct scif_rma_lookup {
  	dma_addr_t *lookup;
  	dma_addr_t offset;
  };
  
  /*
   * struct scif_pinned_pages - A set of pinned pages obtained with
   * scif_pin_pages() which could be part of multiple registered
   * windows across different end points.
   *
   * @nr_pages: Number of pages which is defined as a s64 instead of an int
   * to avoid sign extension with buffers >= 2GB
   * @prot: read/write protections
   * @map_flags: Flags specified during the pin operation
   * @ref_count: Reference count bumped in terms of number of pages
   * @magic: A magic value
   * @pages: Array of pointers to struct pages populated with get_user_pages(..)
   */
  struct scif_pinned_pages {
  	s64 nr_pages;
  	int prot;
  	int map_flags;
  	atomic_t ref_count;
  	u64 magic;
  	struct page **pages;
  };
  
  /*
   * struct scif_status - Stores DMA status update information
   *
   * @src_dma_addr: Source buffer DMA address
   * @val: src location for value to be written to the destination
   * @ep: SCIF endpoint
   */
  struct scif_status {
  	dma_addr_t src_dma_addr;
  	u64 val;
  	struct scif_endpt *ep;
  };
  
  /*
   * struct scif_window - Registration Window for Self and Remote
   *
   * @nr_pages: Number of pages which is defined as a s64 instead of an int
   * to avoid sign extension with buffers >= 2GB
   * @nr_contig_chunks: Number of contiguous physical chunks
   * @prot: read/write protections
   * @ref_count: reference count in terms of number of pages
   * @magic: Cookie to detect corruption
   * @offset: registered offset
   * @va_for_temp: va address that this window represents
   * @dma_mark: Used to determine if all DMAs against the window are done
   * @ep: Pointer to EP. Useful for passing EP around with messages to
  	avoid expensive list traversals.
   * @list: link to list of windows for the endpoint
   * @type: self or peer window
   * @peer_window: Pointer to peer window. Useful for sending messages to peer
   *		 without requiring an extra list traversal
   * @unreg_state: unregistration state
   * @offset_freed: True if the offset has been freed
   * @temp: True for temporary windows created via scif_vreadfrom/scif_vwriteto
   * @mm: memory descriptor for the task_struct which initiated the RMA
   * @st: scatter gather table for DMA mappings with IOMMU enabled
   * @pinned_pages: The set of pinned_pages backing this window
   * @alloc_handle: Handle for sending ALLOC_REQ
   * @regwq: Wait Queue for an registration (N)ACK
   * @reg_state: Registration state
   * @unregwq: Wait Queue for an unregistration (N)ACK
   * @dma_addr_lookup: Lookup for physical addresses used for DMA
   * @nr_lookup: Number of entries in lookup
   * @mapped_offset: Offset used to map the window by the peer
   * @dma_addr: Array of physical addresses used for Mgmt node & MIC initiated DMA
   * @num_pages: Array specifying number of pages for each physical address
   */
  struct scif_window {
  	s64 nr_pages;
  	int nr_contig_chunks;
  	int prot;
  	int ref_count;
  	u64 magic;
  	s64 offset;
  	unsigned long va_for_temp;
  	int dma_mark;
  	u64 ep;
  	struct list_head list;
  	enum scif_window_type type;
  	u64 peer_window;
  	enum scif_msg_state unreg_state;
  	bool offset_freed;
  	bool temp;
  	struct mm_struct *mm;
  	struct sg_table *st;
  	union {
  		struct {
  			struct scif_pinned_pages *pinned_pages;
  			struct scif_allocmsg alloc_handle;
  			wait_queue_head_t regwq;
  			enum scif_msg_state reg_state;
  			wait_queue_head_t unregwq;
  		};
  		struct {
  			struct scif_rma_lookup dma_addr_lookup;
  			struct scif_rma_lookup num_pages_lookup;
  			int nr_lookup;
  			dma_addr_t mapped_offset;
  		};
  	};
  	dma_addr_t *dma_addr;
  	u64 *num_pages;
  } __packed;
  
  /*
   * scif_mmu_notif - SCIF mmu notifier information
   *
   * @mmu_notifier ep_mmu_notifier: MMU notifier operations
   * @tc_reg_list: List of temp registration windows for self
   * @mm: memory descriptor for the task_struct which initiated the RMA
   * @ep: SCIF endpoint
   * @list: link to list of MMU notifier information
   */
  struct scif_mmu_notif {
  #ifdef CONFIG_MMU_NOTIFIER
  	struct mmu_notifier ep_mmu_notifier;
  #endif
  	struct list_head tc_reg_list;
  	struct mm_struct *mm;
  	struct scif_endpt *ep;
  	struct list_head list;
  };
  
  enum scif_rma_dir {
  	SCIF_LOCAL_TO_REMOTE,
  	SCIF_REMOTE_TO_LOCAL
  };
  
  extern struct kmem_cache *unaligned_cache;
  /* Initialize RMA for this EP */
  void scif_rma_ep_init(struct scif_endpt *ep);
  /* Check if epd can be uninitialized */
  int scif_rma_ep_can_uninit(struct scif_endpt *ep);
  /* Obtain a new offset. Callee must grab RMA lock */
  int scif_get_window_offset(struct scif_endpt *ep, int flags,
  			   s64 offset, int nr_pages, s64 *out_offset);
  /* Free offset. Callee must grab RMA lock */
  void scif_free_window_offset(struct scif_endpt *ep,
  			     struct scif_window *window, s64 offset);
  /* Create self registration window */
  struct scif_window *scif_create_window(struct scif_endpt *ep, int nr_pages,
  				       s64 offset, bool temp);
  /* Destroy self registration window.*/
  int scif_destroy_window(struct scif_endpt *ep, struct scif_window *window);
  void scif_unmap_window(struct scif_dev *remote_dev, struct scif_window *window);
  /* Map pages of self window to Aperture/PCI */
  int scif_map_window(struct scif_dev *remote_dev,
  		    struct scif_window *window);
  /* Unregister a self window */
  int scif_unregister_window(struct scif_window *window);
  /* Destroy remote registration window */
  void
  scif_destroy_remote_window(struct scif_window *window);
  /* remove valid remote memory mappings from process address space */
  void scif_zap_mmaps(int node);
  /* Query if any applications have remote memory mappings */
  bool scif_rma_do_apps_have_mmaps(int node);
  /* Cleanup remote registration lists for zombie endpoints */
  void scif_cleanup_rma_for_zombies(int node);
  /* Reserve a DMA channel for a particular endpoint */
  int scif_reserve_dma_chan(struct scif_endpt *ep);
  /* Setup a DMA mark for an endpoint */
  int _scif_fence_mark(scif_epd_t epd, int *mark);
  int scif_prog_signal(scif_epd_t epd, off_t offset, u64 val,
  		     enum scif_window_type type);
  void scif_alloc_req(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_alloc_gnt_rej(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_free_virt(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_recv_reg(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_recv_unreg(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_recv_reg_ack(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_recv_reg_nack(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_recv_unreg_ack(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_recv_unreg_nack(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_recv_munmap(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_recv_mark(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_recv_mark_resp(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_recv_wait(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_recv_wait_resp(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_recv_sig_local(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_recv_sig_remote(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_recv_sig_resp(struct scif_dev *scifdev, struct scifmsg *msg);
  void scif_mmu_notif_handler(struct work_struct *work);
  void scif_rma_handle_remote_fences(void);
  void scif_rma_destroy_windows(void);
  void scif_rma_destroy_tcw_invalid(void);
  int scif_drain_dma_intr(struct scif_hw_dev *sdev, struct dma_chan *chan);
  
  struct scif_window_iter {
  	s64 offset;
  	int index;
  };
  
  static inline void
  scif_init_window_iter(struct scif_window *window, struct scif_window_iter *iter)
  {
  	iter->offset = window->offset;
  	iter->index = 0;
  }
  
  dma_addr_t scif_off_to_dma_addr(struct scif_window *window, s64 off,
  				size_t *nr_bytes,
  				struct scif_window_iter *iter);
  static inline
  dma_addr_t __scif_off_to_dma_addr(struct scif_window *window, s64 off)
  {
  	return scif_off_to_dma_addr(window, off, NULL, NULL);
  }
  
  static inline bool scif_unaligned(off_t src_offset, off_t dst_offset)
  {
  	src_offset = src_offset & (L1_CACHE_BYTES - 1);
  	dst_offset = dst_offset & (L1_CACHE_BYTES - 1);
  	return !(src_offset == dst_offset);
  }
  
  /*
   * scif_zalloc:
   * @size: Size of the allocation request.
   *
   * Helper API which attempts to allocate zeroed pages via
   * __get_free_pages(..) first and then falls back on
   * vzalloc(..) if that fails.
   */
  static inline void *scif_zalloc(size_t size)
  {
  	void *ret = NULL;
  	size_t align = ALIGN(size, PAGE_SIZE);
  
  	if (align && get_order(align) < MAX_ORDER)
  		ret = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
  					       get_order(align));
  	return ret ? ret : vzalloc(align);
  }
  
  /*
   * scif_free:
   * @addr: Address to be freed.
   * @size: Size of the allocation.
   * Helper API which frees memory allocated via scif_zalloc().
   */
  static inline void scif_free(void *addr, size_t size)
  {
  	size_t align = ALIGN(size, PAGE_SIZE);
  
  	if (is_vmalloc_addr(addr))
  		vfree(addr);
  	else
  		free_pages((unsigned long)addr, get_order(align));
  }
  
  static inline void scif_get_window(struct scif_window *window, int nr_pages)
  {
  	window->ref_count += nr_pages;
  }
  
  static inline void scif_put_window(struct scif_window *window, int nr_pages)
  {
  	window->ref_count -= nr_pages;
  }
  
  static inline void scif_set_window_ref(struct scif_window *window, int nr_pages)
  {
  	window->ref_count = nr_pages;
  }
  
  static inline void
  scif_queue_for_cleanup(struct scif_window *window, struct list_head *list)
  {
  	spin_lock(&scif_info.rmalock);
  	list_add_tail(&window->list, list);
  	spin_unlock(&scif_info.rmalock);
  	schedule_work(&scif_info.misc_work);
  }
  
  static inline void __scif_rma_destroy_tcw_helper(struct scif_window *window)
  {
  	list_del_init(&window->list);
  	scif_queue_for_cleanup(window, &scif_info.rma_tc);
  }
  
  static inline bool scif_is_iommu_enabled(void)
  {
  #ifdef CONFIG_INTEL_IOMMU
  	return intel_iommu_enabled;
  #else
  	return false;
  #endif
  }
  #endif /* SCIF_RMA_H */