include/linux/qed/qed_chain.h

/* 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>

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 */
};

enum qed_chain_cnt_type {
	/* The chain's size/prod/cons are kept in 16-bit variables */
	QED_CHAIN_CNT_TYPE_U16,

	/* The chain's size/prod/cons are kept in 32-bit variables  */
	QED_CHAIN_CNT_TYPE_U32,
};

struct qed_chain_next {
	struct regpair	next_phys;
	void		*next_virt;
};

struct qed_chain_pbl_u16 {
	u16 prod_page_idx;
	u16 cons_page_idx;
};

struct qed_chain_pbl_u32 {
	u32 prod_page_idx;
	u32 cons_page_idx;
};

struct qed_chain_pbl {
	/* Base address of a pre-allocated buffer for pbl */
	dma_addr_t	p_phys_table;
	void		*p_virt_table;

	/* Table for keeping the virtual addresses of the chain pages,
	 * respectively to the physical addresses in the pbl table.
	 */
	void **pp_virt_addr_tbl;

	/* Index to current used page by producer/consumer */
	union {
		struct qed_chain_pbl_u16 pbl16;
		struct qed_chain_pbl_u32 pbl32;
	} u;
};

struct qed_chain_u16 {
	/* Cyclic index of next element to produce/consme */
	u16 prod_idx;
	u16 cons_idx;
};

struct qed_chain_u32 {
	/* Cyclic index of next element to produce/consme */
	u32 prod_idx;
	u32 cons_idx;
};

struct qed_chain {
	void			*p_virt_addr;
	dma_addr_t		p_phys_addr;
	void			*p_prod_elem;
	void			*p_cons_elem;

	enum qed_chain_mode	mode;
	enum qed_chain_use_mode intended_use; /* used to produce/consume */
	enum qed_chain_cnt_type cnt_type;

	union {
		struct qed_chain_u16 chain16;
		struct qed_chain_u32 chain32;
	} u;

	u32 page_cnt;

	/* Number of elements - capacity is for usable elements only,
	 * while size will contain total number of elements [for entire chain].
	 */
	u32 capacity;
	u32 size;

	/* Elements information for fast calculations */
	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))

#define is_chain_u16(p) ((p)->cnt_type == QED_CHAIN_CNT_TYPE_U16)
#define is_chain_u32(p) ((p)->cnt_type == QED_CHAIN_CNT_TYPE_U32)

/* Accessors */
static inline u16 qed_chain_get_prod_idx(struct qed_chain *p_chain)
{
	return p_chain->u.chain16.prod_idx;
}

static inline u16 qed_chain_get_cons_idx(struct qed_chain *p_chain)
{
	return p_chain->u.chain16.cons_idx;
}

static inline u32 qed_chain_get_cons_idx_u32(struct qed_chain *p_chain)
{
	return p_chain->u.chain32.cons_idx;
}

static inline u16 qed_chain_get_elem_left(struct qed_chain *p_chain)
{
	u16 used;

	used = (u16) (((u32)0x10000 +
		       (u32)p_chain->u.chain16.prod_idx) -
		      (u32)p_chain->u.chain16.cons_idx);
	if (p_chain->mode == QED_CHAIN_MODE_NEXT_PTR)
		used -= p_chain->u.chain16.prod_idx / p_chain->elem_per_page -
		    p_chain->u.chain16.cons_idx / p_chain->elem_per_page;

	return (u16)(p_chain->capacity - used);
}

static inline u32 qed_chain_get_elem_left_u32(struct qed_chain *p_chain)
{
	u32 used;

	used = (u32) (((u64)0x100000000ULL +
		       (u64)p_chain->u.chain32.prod_idx) -
		      (u64)p_chain->u.chain32.cons_idx);
	if (p_chain->mode == QED_CHAIN_MODE_NEXT_PTR)
		used -= p_chain->u.chain32.prod_idx / p_chain->elem_per_page -
		    p_chain->u.chain32.cons_idx / p_chain->elem_per_page;

	return p_chain->capacity - used;
}

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 u32 qed_chain_get_page_cnt(struct qed_chain *p_chain)
{
	return p_chain->page_cnt;
}

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, void *idx_to_inc, void *page_to_inc)

{
	struct qed_chain_next *p_next = NULL;
	u32 page_index = 0;
	switch (p_chain->mode) {
	case QED_CHAIN_MODE_NEXT_PTR:
		p_next = *p_next_elem;
		*p_next_elem = p_next->next_virt;
		if (is_chain_u16(p_chain))
			*(u16 *)idx_to_inc += p_chain->elem_unusable;
		else
			*(u32 *)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:
		if (is_chain_u16(p_chain)) {
			if (++(*(u16 *)page_to_inc) == p_chain->page_cnt)
				*(u16 *)page_to_inc = 0;
			page_index = *(u16 *)page_to_inc;
		} else {
			if (++(*(u32 *)page_to_inc) == p_chain->page_cnt)
				*(u32 *)page_to_inc = 0;
			page_index = *(u32 *)page_to_inc;
		}
		*p_next_elem = p_chain->pbl.pp_virt_addr_tbl[page_index];
	}
}

#define is_unusable_idx(p, idx)	\
	(((p)->u.chain16.idx & (p)->elem_per_page_mask) == (p)->usable_per_page)

#define is_unusable_idx_u32(p, idx) \
	(((p)->u.chain32.idx & (p)->elem_per_page_mask) == (p)->usable_per_page)
#define is_unusable_next_idx(p, idx)				 \
	((((p)->u.chain16.idx + 1) & (p)->elem_per_page_mask) == \
	 (p)->usable_per_page)

#define is_unusable_next_idx_u32(p, idx)			 \
	((((p)->u.chain32.idx + 1) & (p)->elem_per_page_mask) == \
	 (p)->usable_per_page)

#define test_and_skip(p, idx)						   \
	do {						\
		if (is_chain_u16(p)) {					   \
			if (is_unusable_idx(p, idx))			   \
				(p)->u.chain16.idx += (p)->elem_unusable;  \
		} else {						   \
			if (is_unusable_idx_u32(p, idx))		   \
				(p)->u.chain32.idx += (p)->elem_unusable;  \
		}					\
	} while (0)

/**
 * @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)
{
	if (is_chain_u16(p_chain))
		p_chain->u.chain16.cons_idx++;
	else
		p_chain->u.chain32.cons_idx++;
	test_and_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 *p_ret = NULL, *p_prod_idx, *p_prod_page_idx;

	if (is_chain_u16(p_chain)) {
		if ((p_chain->u.chain16.prod_idx &
		     p_chain->elem_per_page_mask) == p_chain->next_page_mask) {
			p_prod_idx = &p_chain->u.chain16.prod_idx;
			p_prod_page_idx = &p_chain->pbl.u.pbl16.prod_page_idx;
			qed_chain_advance_page(p_chain, &p_chain->p_prod_elem,
					       p_prod_idx, p_prod_page_idx);
		}
		p_chain->u.chain16.prod_idx++;
	} else {
		if ((p_chain->u.chain32.prod_idx &
		     p_chain->elem_per_page_mask) == p_chain->next_page_mask) {
			p_prod_idx = &p_chain->u.chain32.prod_idx;
			p_prod_page_idx = &p_chain->pbl.u.pbl32.prod_page_idx;
			qed_chain_advance_page(p_chain, &p_chain->p_prod_elem,
					       p_prod_idx, p_prod_page_idx);
		}
		p_chain->u.chain32.prod_idx++;
	}

	p_ret = p_chain->p_prod_elem;
	p_chain->p_prod_elem = (void *)(((u8 *)p_chain->p_prod_elem) +
					p_chain->elem_size);

	return p_ret;
}

/**
 * @brief qed_chain_get_capacity -
 *
 * Get the maximum number of BDs in chain
 *
 * @param p_chain
 * @param num
 *
 * @return number of unusable BDs
 */
static inline u32 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_and_skip(p_chain, prod_idx);
	if (is_chain_u16(p_chain))
		p_chain->u.chain16.prod_idx++;
	else
		p_chain->u.chain32.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 *p_ret = NULL, *p_cons_idx, *p_cons_page_idx;

	if (is_chain_u16(p_chain)) {
		if ((p_chain->u.chain16.cons_idx &
		     p_chain->elem_per_page_mask) == p_chain->next_page_mask) {
			p_cons_idx = &p_chain->u.chain16.cons_idx;
			p_cons_page_idx = &p_chain->pbl.u.pbl16.cons_page_idx;
			qed_chain_advance_page(p_chain, &p_chain->p_cons_elem,
					       p_cons_idx, p_cons_page_idx);
		}
		p_chain->u.chain16.cons_idx++;
	} else {
		if ((p_chain->u.chain32.cons_idx &
		     p_chain->elem_per_page_mask) == p_chain->next_page_mask) {
			p_cons_idx = &p_chain->u.chain32.cons_idx;
			p_cons_page_idx = &p_chain->pbl.u.pbl32.cons_page_idx;
		qed_chain_advance_page(p_chain, &p_chain->p_cons_elem,
					       p_cons_idx, p_cons_page_idx);
		}
		p_chain->u.chain32.cons_idx++;
	}

	p_ret = p_chain->p_cons_elem;
	p_chain->p_cons_elem = (void *)(((u8 *)p_chain->p_cons_elem) +
					p_chain->elem_size);

	return p_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)
{
	u32 i;

	if (is_chain_u16(p_chain)) {
		p_chain->u.chain16.prod_idx = 0;
		p_chain->u.chain16.cons_idx = 0;
	} else {
		p_chain->u.chain32.prod_idx = 0;
		p_chain->u.chain32.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) {
		/* Use (page_cnt - 1) as a reset value for the prod/cons page's
		 * indices, to avoid unnecessary page advancing on the first
		 * call to qed_chain_produce/consume. Instead, the indices
		 * will be advanced to page_cnt and then will be wrapped to 0.
		 */
		u32 reset_val = p_chain->page_cnt - 1;

		if (is_chain_u16(p_chain)) {
			p_chain->pbl.u.pbl16.prod_page_idx = (u16)reset_val;
			p_chain->pbl.u.pbl16.cons_page_idx = (u16)reset_val;
		} else {
			p_chain->pbl.u.pbl32.prod_page_idx = reset_val;
			p_chain->pbl.u.pbl32.cons_page_idx = reset_val;
		}
	}

	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_params(struct qed_chain *p_chain,
					 u32 page_cnt,
					 u8 elem_size,
					 enum qed_chain_use_mode intended_use,
					 enum qed_chain_mode mode,
					 enum qed_chain_cnt_type cnt_type)
{
	/* chain fixed parameters */
	p_chain->p_virt_addr = NULL;
	p_chain->p_phys_addr = 0;
	p_chain->elem_size	= elem_size;
	p_chain->intended_use = intended_use;
	p_chain->mode		= mode;
	p_chain->cnt_type = cnt_type;

	p_chain->elem_per_page		= ELEMS_PER_PAGE(elem_size);
	p_chain->usable_per_page = USABLE_ELEMS_PER_PAGE(elem_size, mode);
	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);

	p_chain->page_cnt = page_cnt;
	p_chain->capacity = p_chain->usable_per_page * page_cnt;
	p_chain->size = p_chain->elem_per_page * page_cnt;

	p_chain->pbl.p_phys_table = 0;
	p_chain->pbl.p_virt_table = NULL;
	p_chain->pbl.pp_virt_addr_tbl = NULL;
}

/**
 * @brief qed_chain_init_mem -
 *
 * Initalizes a basic chain struct with its chain buffers
 *
 * @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
 *
 */
static inline void qed_chain_init_mem(struct qed_chain *p_chain,
				      void *p_virt_addr, dma_addr_t p_phys_addr)
{
	p_chain->p_virt_addr = p_virt_addr;
	p_chain->p_phys_addr = p_phys_addr;
}

/**
 * @brief qed_chain_init_pbl_mem -
 *
 * Initalizes a basic chain struct with its pbl buffers
 *
 * @param p_chain
 * @param p_virt_pbl	pointer to a pre allocated side table which will hold
 *                      virtual page addresses.
 * @param p_phys_pbl	pointer to a pre-allocated side table which will hold
 *                      physical page addresses.
 * @param pp_virt_addr_tbl
 *                      pointer to a pre-allocated side table which will hold
 *                      the virtual addresses of the chain pages.
 *
 */
static inline void qed_chain_init_pbl_mem(struct qed_chain *p_chain,
					  void *p_virt_pbl,
					  dma_addr_t p_phys_pbl,
					  void **pp_virt_addr_tbl)
{
	p_chain->pbl.p_phys_table = p_phys_pbl;
	p_chain->pbl.p_virt_table = p_virt_pbl;
	p_chain->pbl.pp_virt_addr_tbl = pp_virt_addr_tbl;
}

/**
 * @brief qed_chain_init_next_ptr_elem -
 *
 * Initalizes a next pointer element
 *
 * @param p_chain
 * @param p_virt_curr	virtual address of a chain page of which the next
 *                      pointer element is initialized
 * @param p_virt_next	virtual address of the next chain page
 * @param p_phys_next	physical address of the next chain page
 *
 */
static inline void
qed_chain_init_next_ptr_elem(struct qed_chain *p_chain,
			     void *p_virt_curr,
			     void *p_virt_next, dma_addr_t p_phys_next)
{
	struct qed_chain_next *p_next;
	u32 size;

	size = p_chain->elem_size * p_chain->usable_per_page;
	p_next = (struct qed_chain_next *)((u8 *)p_virt_curr + size);

	DMA_REGPAIR_LE(p_next->next_phys, p_phys_next);

	p_next->next_virt = p_virt_next;
}

/**
 * @brief qed_chain_get_last_elem -
 *
 * Returns a pointer to the last element of the chain
 *
 * @param p_chain
 *
 * @return void*
 */
static inline void *qed_chain_get_last_elem(struct qed_chain *p_chain)
{
	struct qed_chain_next *p_next = NULL;
	void *p_virt_addr = NULL;
	u32 size, last_page_idx;

	if (!p_chain->p_virt_addr)
		goto out;

	switch (p_chain->mode) {
	case QED_CHAIN_MODE_NEXT_PTR:
		size = p_chain->elem_size * p_chain->usable_per_page;
		p_virt_addr = p_chain->p_virt_addr;
		p_next = (struct qed_chain_next *)((u8 *)p_virt_addr + size);
		while (p_next->next_virt != p_chain->p_virt_addr) {
			p_virt_addr = p_next->next_virt;
			p_next = (struct qed_chain_next *)((u8 *)p_virt_addr +
							   size);
		}
		break;
	case QED_CHAIN_MODE_SINGLE:
		p_virt_addr = p_chain->p_virt_addr;
		break;
	case QED_CHAIN_MODE_PBL:
		last_page_idx = p_chain->page_cnt - 1;
		p_virt_addr = p_chain->pbl.pp_virt_addr_tbl[last_page_idx];
		break;
	}
	/* p_virt_addr points at this stage to the last page of the chain */
	size = p_chain->elem_size * (p_chain->usable_per_page - 1);
	p_virt_addr = (u8 *)p_virt_addr + size;
out:
	return p_virt_addr;
}

/**
 * @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,
				      u32 prod_idx, void *p_prod_elem)
{
	if (is_chain_u16(p_chain))
		p_chain->u.chain16.prod_idx = (u16) prod_idx;
	else
		p_chain->u.chain32.prod_idx = prod_idx;
	p_chain->p_prod_elem = p_prod_elem;
}

/**
 * @brief qed_chain_pbl_zero_mem - set chain memory to 0
 *
 * @param p_chain
 */
static inline void qed_chain_pbl_zero_mem(struct qed_chain *p_chain)
{
	u32 i, page_cnt;

	if (p_chain->mode != QED_CHAIN_MODE_PBL)
		return;

	page_cnt = qed_chain_get_page_cnt(p_chain);

	for (i = 0; i < page_cnt; i++)
		memset(p_chain->pbl.pp_virt_addr_tbl[i], 0,
		       QED_CHAIN_PAGE_SIZE);
}

#endif