//
// Cforall Version 1.0.0 Copyright (C) 2020 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// io/types.hfa --
//
// Author           : Thierry Delisle
// Created On       : Fri Jul 31 16:22:47 2020
// Last Modified By :
// Last Modified On :
// Update Count     :
//

#pragma once

#if defined(CFA_HAVE_LINUX_IO_URING_H)
	extern "C" {
		#include <linux/types.h>
	}

      #include "bits/locks.hfa"

	#define LEADER_LOCK
	struct __leaderlock_t {
		struct $thread * volatile value;	// ($thread) next_leader | (bool:1) is_locked
	};

	static inline void ?{}( __leaderlock_t & this ) { this.value = 0p; }

	//-----------------------------------------------------------------------
	// Ring Data structure
      struct __submition_data {
		// Head and tail of the ring (associated with array)
		volatile __u32 * head;
		volatile __u32 * tail;
		volatile __u32 prev_head;

		// The actual kernel ring which uses head/tail
		// indexes into the sqes arrays
		__u32 * array;

		// number of entries and mask to go with it
		const __u32 * num;
		const __u32 * mask;

		// Submission flags (Not sure what for)
		__u32 * flags;

		// number of sqes not submitted (whatever that means)
		__u32 * dropped;

		// Like head/tail but not seen by the kernel
		volatile __u32 * ready;
		__u32 ready_cnt;
		__u32 prev_ready;

		#if defined(LEADER_LOCK)
			__leaderlock_t submit_lock;
		#else
			__spinlock_t submit_lock;
		#endif
		__spinlock_t  release_lock;

		// A buffer of sqes (not the actual ring)
		struct io_uring_sqe * sqes;

		// The location and size of the mmaped area
		void * ring_ptr;
		size_t ring_sz;
	};

	struct __completion_data {
		// Head and tail of the ring
		volatile __u32 * head;
		volatile __u32 * tail;

		// number of entries and mask to go with it
		const __u32 * mask;
		const __u32 * num;

		// number of cqes not submitted (whatever that means)
		__u32 * overflow;

		// the kernel ring
		struct io_uring_cqe * cqes;

		// The location and size of the mmaped area
		void * ring_ptr;
		size_t ring_sz;
	};

	struct __io_data {
		struct __submition_data submit_q;
		struct __completion_data completion_q;
		__u32 ring_flags;
		int fd;
		bool eager_submits:1;
		bool poller_submits:1;
	};


	//-----------------------------------------------------------------------
	// IO user data
	struct __io_user_data_t {
		__s32 result;
		oneshot sem;
	};

	//-----------------------------------------------------------------------
	// Misc
	// Weirdly, some systems that do support io_uring don't actually define these
	#ifdef __alpha__
		/*
		* alpha is the only exception, all other architectures
		* have common numbers for new system calls.
		*/
		#ifndef __NR_io_uring_setup
			#define __NR_io_uring_setup           535
		#endif
		#ifndef __NR_io_uring_enter
			#define __NR_io_uring_enter           536
		#endif
		#ifndef __NR_io_uring_register
			#define __NR_io_uring_register        537
		#endif
	#else /* !__alpha__ */
		#ifndef __NR_io_uring_setup
			#define __NR_io_uring_setup           425
		#endif
		#ifndef __NR_io_uring_enter
			#define __NR_io_uring_enter           426
		#endif
		#ifndef __NR_io_uring_register
			#define __NR_io_uring_register        427
		#endif
	#endif

	struct epoll_event;
	struct $io_ctx_thread;
	void __ioctx_register($io_ctx_thread & ctx, struct epoll_event & ev);
	void __ioctx_prepare_block($io_ctx_thread & ctx, struct epoll_event & ev);
#endif