/* QLogic qed NIC Driver
   * Copyright (c) 2015 QLogic Corporation
   *
   * This software is available under the terms of the GNU General Public License
   * (GPL) Version 2, available from the file COPYING in the main directory of
   * this source tree.
   */
  
  #ifndef _QED_CHAIN_H
  #define _QED_CHAIN_H
  
  #include <linux/types.h>
  #include <asm/byteorder.h>
  #include <linux/kernel.h>
  #include <linux/list.h>
  #include <linux/slab.h>
  #include <linux/qed/common_hsi.h>
  
  /* dma_addr_t manip */
  #define DMA_LO_LE(x)            cpu_to_le32(lower_32_bits(x))
  #define DMA_HI_LE(x)            cpu_to_le32(upper_32_bits(x))
  
  #define HILO_GEN(hi, lo, type)  ((((type)(hi)) << 32) + (lo))
  #define HILO_DMA(hi, lo)        HILO_GEN(hi, lo, dma_addr_t)
  #define HILO_64(hi, lo) HILO_GEN((le32_to_cpu(hi)), (le32_to_cpu(lo)), u64)
  #define HILO_DMA_REGPAIR(regpair)       (HILO_DMA(regpair.hi, regpair.lo))
  #define HILO_64_REGPAIR(regpair)        (HILO_64(regpair.hi, regpair.lo))
  
  enum qed_chain_mode {
  	/* Each Page contains a next pointer at its end */
  	QED_CHAIN_MODE_NEXT_PTR,
  
  	/* Chain is a single page (next ptr) is unrequired */
  	QED_CHAIN_MODE_SINGLE,
  
  	/* Page pointers are located in a side list */
  	QED_CHAIN_MODE_PBL,
  };
  
  enum qed_chain_use_mode {
  	QED_CHAIN_USE_TO_PRODUCE,		/* Chain starts empty */
  	QED_CHAIN_USE_TO_CONSUME,		/* Chain starts full */
  	QED_CHAIN_USE_TO_CONSUME_PRODUCE,	/* Chain starts empty */
  };
  
  struct qed_chain_next {
  	struct regpair	next_phys;
  	void		*next_virt;
  };
  
  struct qed_chain_pbl {
  	dma_addr_t	p_phys_table;
  	void		*p_virt_table;
  	u16		prod_page_idx;
  	u16		cons_page_idx;
  };
  
  struct qed_chain {
  	void			*p_virt_addr;
  	dma_addr_t		p_phys_addr;
  	void			*p_prod_elem;
  	void			*p_cons_elem;
  	u16			page_cnt;
  	enum qed_chain_mode	mode;
  	enum qed_chain_use_mode intended_use; /* used to produce/consume */
  	u16			capacity; /*< number of _usable_ elements */
  	u16			size; /* number of elements */
  	u16			prod_idx;
  	u16			cons_idx;
  	u16			elem_per_page;
  	u16			elem_per_page_mask;
  	u16			elem_unusable;
  	u16			usable_per_page;
  	u16			elem_size;
  	u16			next_page_mask;
  	struct qed_chain_pbl	pbl;
  };
  
  #define QED_CHAIN_PBL_ENTRY_SIZE        (8)
  #define QED_CHAIN_PAGE_SIZE             (0x1000)
  #define ELEMS_PER_PAGE(elem_size)       (QED_CHAIN_PAGE_SIZE / (elem_size))
  
  #define UNUSABLE_ELEMS_PER_PAGE(elem_size, mode)     \
  	((mode == QED_CHAIN_MODE_NEXT_PTR) ?	     \
  	 (1 + ((sizeof(struct qed_chain_next) - 1) / \
  	       (elem_size))) : 0)
  
  #define USABLE_ELEMS_PER_PAGE(elem_size, mode) \
  	((u32)(ELEMS_PER_PAGE(elem_size) -     \
  	       UNUSABLE_ELEMS_PER_PAGE(elem_size, mode)))
  
  #define QED_CHAIN_PAGE_CNT(elem_cnt, elem_size, mode) \
  	DIV_ROUND_UP(elem_cnt, USABLE_ELEMS_PER_PAGE(elem_size, mode))
  
  /* Accessors */
  static inline u16 qed_chain_get_prod_idx(struct qed_chain *p_chain)
  {
  	return p_chain->prod_idx;
  }
  
  static inline u16 qed_chain_get_cons_idx(struct qed_chain *p_chain)
  {
  	return p_chain->cons_idx;
  }
  
  static inline u16 qed_chain_get_elem_left(struct qed_chain *p_chain)
  {
  	u16 used;
  
  	/* we don't need to trancate upon assignmet, as we assign u32->u16 */
  	used = ((u32)0x10000u + (u32)(p_chain->prod_idx)) -
  		(u32)p_chain->cons_idx;
  	if (p_chain->mode == QED_CHAIN_MODE_NEXT_PTR)
  		used -= p_chain->prod_idx / p_chain->elem_per_page -
  			p_chain->cons_idx / p_chain->elem_per_page;
  
  	return p_chain->capacity - used;
  }
  
  static inline u8 qed_chain_is_full(struct qed_chain *p_chain)
  {
  	return qed_chain_get_elem_left(p_chain) == p_chain->capacity;
  }
  
  static inline u8 qed_chain_is_empty(struct qed_chain *p_chain)
  {
  	return qed_chain_get_elem_left(p_chain) == 0;
  }
  
  static inline u16 qed_chain_get_elem_per_page(
  	struct qed_chain *p_chain)
  {
  	return p_chain->elem_per_page;
  }
  
  static inline u16 qed_chain_get_usable_per_page(
  	struct qed_chain *p_chain)
  {
  	return p_chain->usable_per_page;
  }
  
  static inline u16 qed_chain_get_unusable_per_page(
  	struct qed_chain *p_chain)
  {
  	return p_chain->elem_unusable;
  }
  
  static inline u16 qed_chain_get_size(struct qed_chain *p_chain)
  {
  	return p_chain->size;
  }
  
  static inline dma_addr_t
  qed_chain_get_pbl_phys(struct qed_chain *p_chain)
  {
  	return p_chain->pbl.p_phys_table;
  }
  
  /**
   * @brief qed_chain_advance_page -
   *
   * Advance the next element accros pages for a linked chain
   *
   * @param p_chain
   * @param p_next_elem
   * @param idx_to_inc
   * @param page_to_inc
   */
  static inline void
  qed_chain_advance_page(struct qed_chain *p_chain,
  		       void **p_next_elem,
  		       u16 *idx_to_inc,
  		       u16 *page_to_inc)
  
  {
  	switch (p_chain->mode) {
  	case QED_CHAIN_MODE_NEXT_PTR:
  	{
  		struct qed_chain_next *p_next = *p_next_elem;
  		*p_next_elem = p_next->next_virt;
  		*idx_to_inc += p_chain->elem_unusable;
  		break;
  	}
  	case QED_CHAIN_MODE_SINGLE:
  		*p_next_elem = p_chain->p_virt_addr;
  		break;
  
  	case QED_CHAIN_MODE_PBL:
  		/* It is assumed pages are sequential, next element needs
  		 * to change only when passing going back to first from last.
  		 */
  		if (++(*page_to_inc) == p_chain->page_cnt) {
  			*page_to_inc = 0;
  			*p_next_elem = p_chain->p_virt_addr;
  		}
  	}
  }
  
  #define is_unusable_idx(p, idx)	\
  	(((p)->idx & (p)->elem_per_page_mask) == (p)->usable_per_page)
  
  #define is_unusable_next_idx(p, idx) \
  	((((p)->idx + 1) & (p)->elem_per_page_mask) == (p)->usable_per_page)
  
  #define test_ans_skip(p, idx)				\
  	do {						\
  		if (is_unusable_idx(p, idx)) {		\
  			(p)->idx += (p)->elem_unusable;	\
  		}					\
  	} while (0)
  
  /**
   * @brief qed_chain_return_multi_produced -
   *
   * A chain in which the driver "Produces" elements should use this API
   * to indicate previous produced elements are now consumed.
   *
   * @param p_chain
   * @param num
   */
  static inline void
  qed_chain_return_multi_produced(struct qed_chain *p_chain,
  				u16 num)
  {
  	p_chain->cons_idx += num;
  	test_ans_skip(p_chain, cons_idx);
  }
  
  /**
   * @brief qed_chain_return_produced -
   *
   * A chain in which the driver "Produces" elements should use this API
   * to indicate previous produced elements are now consumed.
   *
   * @param p_chain
   */
  static inline void qed_chain_return_produced(struct qed_chain *p_chain)
  {
  	p_chain->cons_idx++;
  	test_ans_skip(p_chain, cons_idx);
  }
  
  /**
   * @brief qed_chain_produce -
   *
   * A chain in which the driver "Produces" elements should use this to get
   * a pointer to the next element which can be "Produced". It's driver
   * responsibility to validate that the chain has room for new element.
   *
   * @param p_chain
   *
   * @return void*, a pointer to next element
   */
  static inline void *qed_chain_produce(struct qed_chain *p_chain)
  {
  	void *ret = NULL;
  
  	if ((p_chain->prod_idx & p_chain->elem_per_page_mask) ==
  	    p_chain->next_page_mask) {
  		qed_chain_advance_page(p_chain, &p_chain->p_prod_elem,
  				       &p_chain->prod_idx,
  				       &p_chain->pbl.prod_page_idx);
  	}
  
  	ret = p_chain->p_prod_elem;
  	p_chain->prod_idx++;
  	p_chain->p_prod_elem = (void *)(((u8 *)p_chain->p_prod_elem) +
  					p_chain->elem_size);
  
  	return ret;
  }
  
  /**
   * @brief qed_chain_get_capacity -
   *
   * Get the maximum number of BDs in chain
   *
   * @param p_chain
   * @param num
   *
   * @return u16, number of unusable BDs
   */
  static inline u16 qed_chain_get_capacity(struct qed_chain *p_chain)
  {
  	return p_chain->capacity;
  }
  
  /**
   * @brief qed_chain_recycle_consumed -
   *
   * Returns an element which was previously consumed;
   * Increments producers so they could be written to FW.
   *
   * @param p_chain
   */
  static inline void
  qed_chain_recycle_consumed(struct qed_chain *p_chain)
  {
  	test_ans_skip(p_chain, prod_idx);
  	p_chain->prod_idx++;
  }
  
  /**
   * @brief qed_chain_consume -
   *
   * A Chain in which the driver utilizes data written by a different source
   * (i.e., FW) should use this to access passed buffers.
   *
   * @param p_chain
   *
   * @return void*, a pointer to the next buffer written
   */
  static inline void *qed_chain_consume(struct qed_chain *p_chain)
  {
  	void *ret = NULL;
  
  	if ((p_chain->cons_idx & p_chain->elem_per_page_mask) ==
  	    p_chain->next_page_mask) {
  		qed_chain_advance_page(p_chain, &p_chain->p_cons_elem,
  				       &p_chain->cons_idx,
  				       &p_chain->pbl.cons_page_idx);
  	}
  
  	ret = p_chain->p_cons_elem;
  	p_chain->cons_idx++;
  	p_chain->p_cons_elem = (void *)(((u8 *)p_chain->p_cons_elem) +
  					p_chain->elem_size);
  
  	return ret;
  }
  
  /**
   * @brief qed_chain_reset - Resets the chain to its start state
   *
   * @param p_chain pointer to a previously allocted chain
   */
  static inline void qed_chain_reset(struct qed_chain *p_chain)
  {
  	int i;
  
  	p_chain->prod_idx	= 0;
  	p_chain->cons_idx	= 0;
  	p_chain->p_cons_elem	= p_chain->p_virt_addr;
  	p_chain->p_prod_elem	= p_chain->p_virt_addr;
  
  	if (p_chain->mode == QED_CHAIN_MODE_PBL) {
  		p_chain->pbl.prod_page_idx	= p_chain->page_cnt - 1;
  		p_chain->pbl.cons_page_idx	= p_chain->page_cnt - 1;
  	}
  
  	switch (p_chain->intended_use) {
  	case QED_CHAIN_USE_TO_CONSUME_PRODUCE:
  	case QED_CHAIN_USE_TO_PRODUCE:
  		/* Do nothing */
  		break;
  
  	case QED_CHAIN_USE_TO_CONSUME:
  		/* produce empty elements */
  		for (i = 0; i < p_chain->capacity; i++)
  			qed_chain_recycle_consumed(p_chain);
  		break;
  	}
  }
  
  /**
   * @brief qed_chain_init - Initalizes a basic chain struct
   *
   * @param p_chain
   * @param p_virt_addr
   * @param p_phys_addr	physical address of allocated buffer's beginning
   * @param page_cnt	number of pages in the allocated buffer
   * @param elem_size	size of each element in the chain
   * @param intended_use
   * @param mode
   */
  static inline void qed_chain_init(struct qed_chain *p_chain,
  				  void *p_virt_addr,
  				  dma_addr_t p_phys_addr,
  				  u16 page_cnt,
  				  u8 elem_size,
  				  enum qed_chain_use_mode intended_use,
  				  enum qed_chain_mode mode)
  {
  	/* chain fixed parameters */
  	p_chain->p_virt_addr	= p_virt_addr;
  	p_chain->p_phys_addr	= p_phys_addr;
  	p_chain->elem_size	= elem_size;
  	p_chain->page_cnt	= page_cnt;
  	p_chain->mode		= mode;
  
  	p_chain->intended_use		= intended_use;
  	p_chain->elem_per_page		= ELEMS_PER_PAGE(elem_size);
  	p_chain->usable_per_page =
  		USABLE_ELEMS_PER_PAGE(elem_size, mode);
  	p_chain->capacity		= p_chain->usable_per_page * page_cnt;
  	p_chain->size			= p_chain->elem_per_page * page_cnt;
  	p_chain->elem_per_page_mask	= p_chain->elem_per_page - 1;
  
  	p_chain->elem_unusable = UNUSABLE_ELEMS_PER_PAGE(elem_size, mode);
  
  	p_chain->next_page_mask = (p_chain->usable_per_page &
  				   p_chain->elem_per_page_mask);
  
  	if (mode == QED_CHAIN_MODE_NEXT_PTR) {
  		struct qed_chain_next	*p_next;
  		u16			i;
  
  		for (i = 0; i < page_cnt - 1; i++) {
  			/* Increment mem_phy to the next page. */
  			p_phys_addr += QED_CHAIN_PAGE_SIZE;
  
  			/* Initialize the physical address of the next page. */
  			p_next = (struct qed_chain_next *)((u8 *)p_virt_addr +
  							   elem_size *
  							   p_chain->
  							   usable_per_page);
  
  			p_next->next_phys.lo	= DMA_LO_LE(p_phys_addr);
  			p_next->next_phys.hi	= DMA_HI_LE(p_phys_addr);
  
  			/* Initialize the virtual address of the next page. */
  			p_next->next_virt = (void *)((u8 *)p_virt_addr +
  						     QED_CHAIN_PAGE_SIZE);
  
  			/* Move to the next page. */
  			p_virt_addr = p_next->next_virt;
  		}
  
  		/* Last page's next should point to beginning of the chain */
  		p_next = (struct qed_chain_next *)((u8 *)p_virt_addr +
  						   elem_size *
  						   p_chain->usable_per_page);
  
  		p_next->next_phys.lo	= DMA_LO_LE(p_chain->p_phys_addr);
  		p_next->next_phys.hi	= DMA_HI_LE(p_chain->p_phys_addr);
  		p_next->next_virt	= p_chain->p_virt_addr;
  	}
  	qed_chain_reset(p_chain);
  }
  
  /**
   * @brief qed_chain_pbl_init - Initalizes a basic pbl chain
   *        struct
   * @param p_chain
   * @param p_virt_addr	virtual address of allocated buffer's beginning
   * @param p_phys_addr	physical address of allocated buffer's beginning
   * @param page_cnt	number of pages in the allocated buffer
   * @param elem_size	size of each element in the chain
   * @param use_mode
   * @param p_phys_pbl	pointer to a pre-allocated side table
   *                      which will hold physical page addresses.
   * @param p_virt_pbl	pointer to a pre allocated side table
   *                      which will hold virtual page addresses.
   */
  static inline void
  qed_chain_pbl_init(struct qed_chain *p_chain,
  		   void *p_virt_addr,
  		   dma_addr_t p_phys_addr,
  		   u16 page_cnt,
  		   u8 elem_size,
  		   enum qed_chain_use_mode use_mode,
  		   dma_addr_t p_phys_pbl,
  		   dma_addr_t *p_virt_pbl)
  {
  	dma_addr_t *p_pbl_dma = p_virt_pbl;
  	int i;
  
  	qed_chain_init(p_chain, p_virt_addr, p_phys_addr, page_cnt,
  		       elem_size, use_mode, QED_CHAIN_MODE_PBL);
  
  	p_chain->pbl.p_phys_table = p_phys_pbl;
  	p_chain->pbl.p_virt_table = p_virt_pbl;
  
  	/* Fill the PBL with physical addresses*/
  	for (i = 0; i < page_cnt; i++) {
  		*p_pbl_dma = p_phys_addr;
  		p_phys_addr += QED_CHAIN_PAGE_SIZE;
  		p_pbl_dma++;
  	}
  }
  
  /**
   * @brief qed_chain_set_prod - sets the prod to the given
   *        value
   *
   * @param prod_idx
   * @param p_prod_elem
   */
  static inline void qed_chain_set_prod(struct qed_chain *p_chain,
  				      u16 prod_idx,
  				      void *p_prod_elem)
  {
  	p_chain->prod_idx	= prod_idx;
  	p_chain->p_prod_elem	= p_prod_elem;
  }
  
  /**
   * @brief qed_chain_get_elem -
   *
   * get a pointer to an element represented by absolute idx
   *
   * @param p_chain
   * @assumption p_chain->size is a power of 2
   *
   * @return void*, a pointer to next element
   */
  static inline void *qed_chain_sge_get_elem(struct qed_chain *p_chain,
  					   u16 idx)
  {
  	void *ret = NULL;
  
  	if (idx >= p_chain->size)
  		return NULL;
  
  	ret = (u8 *)p_chain->p_virt_addr + p_chain->elem_size * idx;
  
  	return ret;
  }
  
  /**
   * @brief qed_chain_sge_inc_cons_prod
   *
   * for sge chains, producer isn't increased serially, the ring
   * is expected to be full at all times. Once elements are
   * consumed, they are immediately produced.
   *
   * @param p_chain
   * @param cnt
   *
   * @return inline void
   */
  static inline void
  qed_chain_sge_inc_cons_prod(struct qed_chain *p_chain,
  			    u16 cnt)
  {
  	p_chain->prod_idx += cnt;
  	p_chain->cons_idx += cnt;
  }
  
  #endif