/*
 * Copyright 2011 Stefan Lankes, Chair for Operating Systems,
 *                               RWTH Aachen University
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * This file is part of MetalSVM. 
 */

#include <metalsvm/stddef.h>
#include <metalsvm/stdio.h>
#include <metalsvm/stdlib.h>
#include <metalsvm/mmu.h>
#include <metalsvm/page.h>
#include <metalsvm/errno.h>
#include <asm/irqflags.h>
#include <asm/processor.h>
#ifdef CONFIG_ROCKCREEK
#include <asm/RCCE.h>
#include <asm/RCCE_lib.h>
#include <asm/iRCCE.h>
#include <asm/SCC_API.h>
#include <asm/icc.h>
#include <asm/svm.h>

#define SHARED_PAGES		(RCCE_SHM_SIZE_MAX >> PAGE_SHIFT)
#define OWNER_SIZE		((SHARED_PAGES * sizeof(uint8_t) + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1))

t_vcharp RC_SHM_BUFFER_START();

/*
 * This array describes the owner of a specific page.
 * Only the owner of a page is able to change the possession.
 * => No lock is needded.
 */
static volatile uint8_t*	page_owner = NULL;

// helper array to convert a physical to a virtual address
static size_t phys2virt[SHARED_PAGES] = {[0 ... SHARED_PAGES-1] = 0};
static size_t shmbegin = 0;
static int my_ue = 0;
static uint32_t emit[RCCE_MAXNP] = {[0 ... RCCE_MAXNP-1] = 0};
static uint32_t request[RCCE_MAXNP] = {[0 ... RCCE_MAXNP-1] = 0};
static uint32_t forward[RCCE_MAXNP] = {[0 ... RCCE_MAXNP-1] = 0};

int svm_init(void)
{
	size_t phyaddr;
	uint32_t flags;

	// iRCCE is not thread save => disable interrupts
	flags = irq_nested_disable();
	my_ue = RCCE_ue();
	shmbegin = (size_t)RC_SHM_BUFFER_START();
	phyaddr = (size_t) RCCE_shmalloc(OWNER_SIZE);
	irq_nested_enable(flags);

	if (BUILTIN_EXPECT(!phyaddr, 0))
		return -ENOMEM;
	if (BUILTIN_EXPECT(phyaddr & 0xFFF, 0)) {
		kprintf("RCCE_shmalloc returns not a page aligned physiacl address: 0x%x\n", phyaddr);
		return -ENOMEM;
	}

	kprintf("Shared memory starts at the physical address 0x%x\n", shmbegin);
 
	page_owner = (uint8_t*) map_region(0, phyaddr, OWNER_SIZE >> PAGE_SHIFT, MAP_KERNEL_SPACE|MAP_NO_CACHE);
	if (BUILTIN_EXPECT(!page_owner, 0)) {
		flags = irq_nested_disable();
		RCCE_shfree((t_vcharp) phyaddr);
		irq_nested_enable(flags);
		return -ENOMEM;
	}

	// per default is core 0 owner
	if (!my_ue)
		memset((void*)page_owner, 0x00, OWNER_SIZE);

	// iRCCE is not thread save => disable interrupts
	flags = irq_nested_disable();
	RCCE_barrier(&RCCE_COMM_WORLD);
	irq_nested_enable(flags);
	
	return 0;
}

/*
 * This function is called by the pagefault handler
 * => the interrupt flags is already cleared 
 */
int svm_access_request(size_t addr)
{
	size_t phyaddr = virt_to_phys(addr);
	uint32_t pageid;
	int remote_rank;
	uint8_t payload[iRCCE_MAIL_HEADER_PAYLOAD];

	if (phyaddr < shmbegin)
		return -EINVAL;
	if (phyaddr >= shmbegin + RCCE_SHM_SIZE_MAX)
		return -EINVAL;
	pageid = (phyaddr-shmbegin) >> PAGE_SHIFT;

	//svm_flush();
	if (page_owner[pageid] == my_ue)
		return 0;

	remote_rank = page_owner[pageid];
	((size_t*) payload)[0] = my_ue;
	((size_t*) payload)[1] = phyaddr;

	//kprintf("send access request to %d of 0x%x\n", remote_rank, phyaddr);
	/* send ping request */
	iRCCE_mail_send(2*sizeof(size_t), ICC_TAG_SVMREQUEST, 0, payload, remote_rank);

	request[remote_rank]++;
        NOP8;
        icc_send_irq(remote_rank);

	/* check for incoming messages */
	icc_mail_check();

	while (page_owner[pageid] != my_ue) {
		NOP4;
	}

	return change_page_permissions(addr, addr+PAGE_SIZE, VMA_READ|VMA_WRITE|VMA_CACHEABLE);
}

void* svmmalloc(size_t size, uint32_t consistency)
{
	size_t phyaddr, viraddr, i;
	uint32_t flags;
	uint32_t map_flags = MAP_KERNEL_SPACE|MAP_MPE;

	if (consistency & SVM_STRONG)
		map_flags |= MAP_SVM_STRONG;
	else if (consistency & SVM_LAZYRELEASE)
		map_flags |= MAP_SVM_LAZYRELEASE;
	else return 0;

	// currently, we allocate memory in page size granulation
	size = (size + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1);

	// iRCCE is not thread save => disable interrupts
	flags = irq_nested_disable();
	phyaddr = (size_t) RCCE_shmalloc(size);

	if (RCCE_ue() && (consistency & SVM_STRONG))
		map_flags |= MAP_NO_ACCESS;
	irq_nested_enable(flags);

	if (BUILTIN_EXPECT(!phyaddr, 0))
		return NULL;
	if (BUILTIN_EXPECT(phyaddr & 0xFFF, 0)) {
		kprintf("RCCE_shmalloc returns not a page aligned physiacl address: 0x%x\n", phyaddr);
		return NULL;
	}

	viraddr = map_region(0, phyaddr, size >> PAGE_SHIFT, map_flags);
	for(i=0; i<size; i+=PAGE_SIZE)
		phys2virt[(phyaddr + i - shmbegin) >> PAGE_SHIFT] = viraddr + i;

	kprintf("svmmalloc: phyaddr 0x%x, viraddr 0x%x, size 0x%x\n", phyaddr, viraddr, size);

	return (void*) viraddr;
}

void svmfree(void* addr, size_t size)
{
	size_t phyaddr, i;
	uint32_t flags;

	if (BUILTIN_EXPECT(!addr || !size, 0))
		return;

	phyaddr = virt_to_phys((size_t) addr);

	// currently, we allocate memory in page size granulation
	size = (size + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1);

	kprintf("svmfree: phyaddr 0x%x, viraddr 0x%x, size 0x%x\n", phyaddr, addr, size);

	unmap_region((size_t) addr, size >> PAGE_SHIFT);
	for(i=0; i<size; i+=PAGE_SIZE)
		phys2virt[(phyaddr + i - shmbegin) >> PAGE_SHIFT] = 0;

	// iRCCE is not thread save => disable interrupts
	flags = irq_nested_disable();
	RCCE_shfree((t_vcharp) phyaddr);
	irq_nested_enable(flags);
}

/*
 * This function is called by icc_mail_check.
 * => Interrupt flag is alread cleared.
 */
int svm_emit_page(size_t phyaddr, int ue)
{	
	uint32_t pageid;

	//kprintf("Try to emit page 0x%x to %d\n", phyaddr, ue);

	if (phyaddr < shmbegin)
		return -EINVAL;
	if (phyaddr >= shmbegin + RCCE_SHM_SIZE_MAX)
		return -EINVAL;
	pageid = (phyaddr-shmbegin) >> PAGE_SHIFT;

	if (page_owner[pageid] != my_ue) {
		// Core is nor owner => forward request to new owner
		int remote_rank;
		uint8_t payload[iRCCE_MAIL_HEADER_PAYLOAD];

		kprintf("Ups, core %d is not owner of page 0x%x\n", my_ue, phyaddr);

		remote_rank = page_owner[pageid];
		((size_t*) payload)[0] = ue;
		((size_t*) payload)[1] = phyaddr;

		/* send ping request */
		iRCCE_mail_send(2*sizeof(size_t), ICC_TAG_SVMREQUEST, 0, payload, remote_rank);

		NOP8;
		icc_send_irq(remote_rank);

		forward[remote_rank]++;
	} else {
		size_t viraddr;

		svm_flush();
		page_owner[pageid] = ue;

		emit[ue]++;
		viraddr = phys2virt[(phyaddr - shmbegin) >> PAGE_SHIFT];
		change_page_permissions(viraddr, viraddr+PAGE_SIZE, VMA_NOACCESS|VMA_READ|VMA_CACHEABLE);
	}

	return 0;
}

#ifdef SVM_WB
void svm_flush(void)
{
	int z, tmp;

        // need to write to another line to make sure the write combine buffer gets flushed
        *(int *)RCCE_fool_write_combine_buffer = 1;
        flush_cache();

#if 0
	// try to flush L2 cache
	z = Z_PID(RC_COREID[my_ue]);
	tmp=ReadConfigReg(CRB_OWN + (z==0 ? GLCFG0 : GLCFG1));
	tmp &= ~(1 << GLCFG_XFLSHNN_BIT);
	SetConfigReg(CRB_OWN + (z==0 ? GLCFG0 : GLCFG1), tmp);

	while(!(ReadConfigReg(CRB_OWN + (z==0 ? GLCFG0 : GLCFG1)) & (1 << GLCFG_XFLSHNN_BIT))) {
		NOP8;
	}
#endif
}
#endif

int svm_statistics(void)
{
	uint32_t i;

	kprintf("emit\t:");
	for(i=0; i<RCCE_MAXNP; i++)
		kprintf("\t%u", emit[i]);
	kprintf("\nrequest\t:");
	for(i=0; i<RCCE_MAXNP; i++) 
		kprintf("\t%u", request[i]);
	kprintf("\nforward\t:");
	for(i=0; i<RCCE_MAXNP; i++)
		kprintf("\t%u", forward[i]);
	kputs("\n");

	return 0;
}

#endif